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Table representation of search results timeline featuring number of search results per year.
Year
Number of Results
1961
2
1963
2
1964
7
1965
1
1966
2
1967
168
1968
264
1969
202
1970
137
1971
134
1972
186
1973
283
1974
312
1975
194
1976
185
1977
219
1978
312
1979
293
1980
422
1981
356
1982
411
1983
459
1984
452
1985
551
1986
506
1987
516
1988
549
1989
456
1990
451
1991
612
1992
575
1993
490
1994
616
1995
494
1996
577
1997
760
1998
842
1999
1122
2000
1301
2001
1114
2002
1042
2003
1172
2004
1390
2005
1555
2006
1707
2007
2002
2008
2104
2009
2451
2010
2471
2011
2369
2012
2365
2013
2516
2014
2311
2015
2072
2016
1867
2017
1675
2018
1546
2019
1367
2020
1080
2021
566
2022
300
2023
363
2024
281
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AMA
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Adaptive Clinical Trial
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Autobiography
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Case Reports
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Clinical Conference
Clinical Study
Clinical Trial Protocol
Clinical Trial, Phase I
Clinical Trial, Phase II
Clinical Trial, Phase III
Clinical Trial, Phase IV
Clinical Trial, Veterinary
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Consensus Development Conference
Consensus Development Conference, NIH
Controlled Clinical Trial
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English Abstract
Equivalence Trial
Evaluation Study
Expression of Concern
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Guideline
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Interactive Tutorial
Interview
Introductory Journal Article
Lecture
Legal Case
Legislation
Letter
Multicenter Study
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Newspaper Article
Observational Study
Observational Study, Veterinary
Overall
Patient Education Handout
Periodical Index
Personal Narrative
Portrait
Practice Guideline
Pragmatic Clinical Trial
Preprint
Published Erratum
Randomized Controlled Trial, Veterinary
Research Support, American Recovery and Reinvestment Act
Research Support, N.I.H., Extramural
Research Support, N.I.H., Intramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.
Research Support, U.S. Gov't
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Scientific Integrity Review
Technical Report
Twin Study
Validation Study
Video-Audio Media
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