tezr retrieves, parses, caches, and checks thesis metadata from Turkiye’s National Thesis Center (NTC, Ulusal Tez Merkezi).
The NTC is the Council of Higher Education’s national portal for graduate thesis records from Turkish universities. It exposes thesis titles, authors, institutions, degree types, languages, subjects, abstracts, advisors, page counts, access status, and detail-page links through a public web interface. The portal contains close to one million records, but it has no documented public API, no bulk export, and a visible-result cap of 2,000 rows per query.
tezr turns that capped web-only archive into a scriptable R workflow. It maps the basic, advanced, and detailed search forms into R functions. It resolves valid university, institute, division, discipline, and subject labels. It retrieves detail pages, parses bilingual metadata into tibbles, deduplicates merged searches, caches repeated queries, paginates large searches by adaptive year ranges, and exposes statistics functions for retrieval checks.
tezr is not affiliated with, endorsed by, or connected to YÖK, the Council of Higher Education, or the National Thesis Center.
Installation
# install.packages("pak")
pak::pak("emraher/tezr")Quick Start
Search results use title_original and title_translation. Detail records use abstract_original and abstract_translation.
household <- search_basic(keyword = "hanehalkı")
dplyr::glimpse(household)A representative search result has this shape.
#> Rows: 8
#> Columns: 13
#> $ thesis_no <chr> "967755", "975988", "955779", "974976", "960162", "9…
#> $ title_original <chr> "Hanehalki gelir ve tuketim analizi 1", "Hanehalki g…
#> $ title_translation <chr> "Household income and consumption analysis 1", "Hous…
#> $ author <chr> "PERIHAN EZGI BALLI", "CENAP ALAYBEYI", "SECIL ALMIS…
#> $ university <chr> "Bandirma Onyedi Eylul Universitesi", "Harran Univer…
#> $ year <int> 2025, 2025, 2025, 2024, 2023, 2022, 2021, 2020
#> $ thesis_type_tr <chr> "Doktora", "Yuksek Lisans", "Yuksek Lisans", "Yuksek…
#> $ thesis_type_en <chr> "Doctorate", "Master", "Master", "Master", "Doctorat…
#> $ language_tr <chr> "Turkce", "Turkce", "Turkce", "Turkce", "Turkce", "I…
#> $ language_en <chr> "Turkish", "Turkish", "Turkish", "Turkish", "Turkish…
#> $ subject_tr <chr> "Ekonomi", "Ekonomi", "Ekonomi", "Ekonomi", "Ekonomi…
#> $ subject_en <chr> "Economics", "Economics", "Economics", "Economics", …
#> $ detail_id <chr> "TCKf4ksTOVsOBqUcPYMKWQ", "LypZzbdoWcG0f3c62wverw", …
climate_change <- search_advanced(
keyword = "iklim değişikliği",
year_start = 2015,
group = "science"
)
dplyr::glimpse(climate_change)#> Rows: 24
#> Columns: 13
#> $ thesis_no <chr> "9677551", "9759882", "9557793", "9749764", "9601625…
#> $ title_original <chr> "Iklim degisikligi 1", "Iklim degisikligi 2", "Iklim…
#> $ title_translation <chr> "Climate change 1", "Climate change 2", "Climate cha…
#> $ author <chr> "PERIHAN EZGI BALLI", "CENAP ALAYBEYI", "SECIL ALMIS…
#> $ university <chr> "Ankara Universitesi", "Istanbul Universitesi", "Ege…
#> $ year <int> 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023…
#> $ thesis_type_tr <chr> "Doktora", "Yuksek Lisans", "Yuksek Lisans", "Yuksek…
#> $ thesis_type_en <chr> "Master", "Doctorate", "Master", "Doctorate", "Maste…
#> $ language_tr <chr> "Turkce", "Turkce", "Turkce", "Turkce", "Turkce", "I…
#> $ language_en <chr> "Turkish", "Turkish", "Turkish", "Turkish", "Turkish…
#> $ subject_tr <chr> "Cevre Bilimleri; Ekonomi", "Cevre Bilimleri; Ekonom…
#> $ subject_en <chr> "Environmental Sciences; Economics", "Environmental …
#> $ detail_id <chr> "TCKf4ksTOVsOBqUcPYMKWQ", "LypZzbdoWcG0f3c62wverw", …
phd_theses <- search_detailed(
university = "Ankara Üniversitesi",
division = "İktisat Ana Bilim Dalı",
thesis_type = "phd",
year_start = 2020
)
head(phd_theses)#> # A tibble: 6 × 13
#> thesis_no title_original title_translation author university year
#> <chr> <chr> <chr> <chr> <chr> <int>
#> 1 9677551 Parasal aktarım mekanizma… Domestic credit … PERIH… Ankara Un… 2020
#> 2 9759882 1980 sonrası Türkiye'de a… Changes in sunfl… CENAP… Ankara Un… 2021
#> 3 9557793 Doğrudan yabancı yatırıml… Foreign direct i… SECIL… Ankara Un… 2022
#> 4 9749764 Enerji kullanımı ile G-20… Panel data analy… RUMEY… Ankara Un… 2023
#> 5 9601625 Finansal liberalleşme sür… Fragility during… SAMI … Ankara Un… 2024
#> 6 9465806 Azerbaycan'ın ekolojik ay… An analysis of A… ADIL … Ankara Un… 2025
#> # ℹ 7 more variables: thesis_type_tr <chr>, thesis_type_en <chr>,
#> # language_tr <chr>, language_en <chr>, subject_tr <chr>, subject_en <chr>,
#> # detail_id <chr>
details <- detail(phd_theses$detail_id[1])
details |>
tidyr::pivot_longer(
cols = dplyr::everything(),
names_to = "colname",
values_to = "colvalue"
) |>
print(n = 24)#> # A tibble: 24 × 2
#> colname colvalue
#> <chr> <chr>
#> 1 thesis_no 9677551
#> 2 title_original Parasal aktarim mekanizmasi cercevesinde ozel sektore k…
#> 3 title_translation Domestic credit to private sector and monetary transmis…
#> 4 author PERIHAN EZGI BALLI
#> 5 advisor PROF. DR. HASAN SAHIN
#> 6 co_advisor <NA>
#> 7 university Ankara Universitesi
#> 8 institute Sosyal Bilimler Enstitusu
#> 9 division Iktisat Ana Bilim Dali
#> 10 year 2020
#> 11 pages 153
#> 12 thesis_type_tr Doktora
#> 13 thesis_type_en Doctorate
#> 14 language_tr Turkce
#> 15 language_en Turkish
#> 16 subject_tr Ekonomi; Enerji
#> 17 subject_en Economics; Energy
#> 18 abstract_original Enerji piyasasi duzenlemelerinin ana ekseninde enerji a…
#> 19 abstract_translation This thesis consists of three essays on energy market r…
#> 20 keywords_tr Enerji piyasalari; Duzenleme; Elektrik
#> 21 keywords_en Energy markets; Regulation; Electricity
#> 22 access_status open
#> 23 pdf_url https://tez.yok.gov.tr/UlusalTezMerkezi/tezIndir.jsp?id…
#> 24 detail_url https://tez.yok.gov.tr/UlusalTezMerkezi/tezDetay.jsp?id…Save returned objects after large queries so later analysis does not repeat the same portal requests.
Scope
The primary rOpenSci category is data retrieval. The secondary use case is bibliometrics and thesis metadata analysis.
Adjacent packages such as rentrez and europepmc wrap formal scholarly APIs. tezr differs because the NTC only exposes a web portal and uses structured form fields rather than a query language. bibliometrix focuses on bibliometric analysis after data are already available. tezr focuses on retrieval, parsing, completeness checks, and preparation of NTC thesis metadata for analysis. Turkish higher-education data packages, when available, usually target institutional or public statistics sources rather than the NTC thesis-record portal.
Responsible Use
Use tezr for academic, reproducible research workflows. Respect the NTC portal, avoid unnecessary repeated requests, and cache or save results locally. Do not use the package to bypass access restrictions, to scrape thesis full text at scale, or to redistribute metadata in ways that conflict with the source portal’s terms.
When publishing results, cite both tezr and the NTC or Council of Higher Education data source. Also document the query terms, filters, retrieval dates, and any completeness warnings returned by tezr.
The project follows the rOpenSci Code of Conduct. Do not post private researcher data, access tokens, local cookies, or sensitive institutional details in issues or pull requests.
Request Behavior
tezr sends a package-identifying user agent by default. Override it with request_config(user_agent = "...") or TEZR_USER_AGENT if your institution or the portal requires a different header.
request_config(user_agent = "my-lab-contact@example.edu")
request_config(reset = TRUE)Set request_config(verbose = FALSE) or TEZR_VERBOSE=false to silence informational progress messages. Warnings and errors are still shown.
The package applies a two-second request delay, retries requests up to three times through httr2, refreshes sessions after 50 logical requests or 20 minutes, and caches searches, range chunks, details, and lookups in memory. Detail requests use bounded parallel fetching for uncached records.
More Than Downloading
tezr adds workflow behavior that is not available from the NTC web interface.
- Filtered basic, advanced, and detailed search functions.
- Lookup resolution for valid NTC labels and IDs.
- Adaptive pagination for queries that exceed the 2,000-row portal cap.
- Parsing of bilingual search and detail metadata into rectangular tibbles.
- Deduplication for expanded multi-value detailed searches.
- Completeness attributes that record reported totals, pagination status, and single-year overflow.
- In-memory caching for repeated searches, detail pages, range chunks, and lookup lists.
- Aggregate statistics functions that help compare retrieved records against portal counts.
Limitations
- The NTC has no public API. Markup, form fields, cookies, or JavaScript behavior may change without notice.
- Search results are capped at 2,000 rows per portal request.
- Auto-pagination cannot split below a single calendar year. Single-year overflow can still leave results incomplete.
- Metadata quality is uneven. Fields can be missing, duplicated, inconsistently translated, or encoded differently across records.
- The package retrieves metadata and detail-page links. It does not download thesis full text.
- The package depends on live portal availability. Network failures, certificate issues, and server-side blocking can affect retrieval.
Maintenance
The package is maintained as active research software. The current public API is intended to be review-ready, but the development version may still make breaking changes in response to rOpenSci review before a stable release. The maintainer commits to at least two years of maintenance after review acceptance, including fixes for NTC markup changes when feasible.