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Table representation of search results timeline featuring number of search results per year.
Year
Number of Results
1952
1
1953
1
1954
2
1955
4
1956
1
1957
1
1958
4
1959
8
1960
4
1961
2
1962
4
1965
2
1966
16
1967
41
1968
60
1969
81
1970
61
1971
66
1972
79
1973
68
1974
62
1975
53
1976
31
1977
21
1978
33
1979
29
1980
31
1981
25
1982
27
1983
33
1984
55
1985
63
1986
61
1987
48
1988
60
1989
39
1990
53
1991
41
1992
40
1993
33
1994
38
1995
35
1996
30
1997
25
1998
29
1999
28
2000
32
2001
23
2002
27
2003
26
2004
27
2005
33
2006
32
2007
25
2008
26
2009
30
2010
14
2011
21
2012
24
2013
32
2014
26
2015
22
2016
29
2017
23
2018
27
2019
11
2020
9
2021
7
2022
1
2023
3
2024
4
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AMA
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Adaptive Clinical Trial
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Autobiography
Bibliography
Biography
Case Reports
Classical Article
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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Comment
Comparative Study
Congress
Consensus Development Conference
Consensus Development Conference, NIH
Controlled Clinical Trial
Corrected and Republished Article
Dataset
Dictionary
Directory
Duplicate Publication
Editorial
Electronic Supplementary Materials
English Abstract
Equivalence Trial
Evaluation Study
Expression of Concern
Festschrift
Government Publication
Guideline
Historical Article
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
Retracted Publication
Retraction of Publication
Scientific Integrity Review
Technical Report
Twin Study
Validation Study
Video-Audio Media
Webcast
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