全文获取类型
收费全文 | 45993篇 |
免费 | 1900篇 |
国内免费 | 26篇 |
专业分类
47919篇 |
出版年
2020年 | 545篇 |
2019年 | 588篇 |
2018年 | 980篇 |
2017年 | 928篇 |
2016年 | 967篇 |
2015年 | 647篇 |
2014年 | 819篇 |
2013年 | 3771篇 |
2012年 | 1523篇 |
2011年 | 1612篇 |
2010年 | 932篇 |
2009年 | 914篇 |
2008年 | 1310篇 |
2007年 | 1316篇 |
2006年 | 1174篇 |
2005年 | 1070篇 |
2004年 | 943篇 |
2003年 | 918篇 |
2002年 | 922篇 |
2001年 | 1474篇 |
2000年 | 1430篇 |
1999年 | 1084篇 |
1998年 | 457篇 |
1997年 | 405篇 |
1996年 | 417篇 |
1992年 | 895篇 |
1991年 | 839篇 |
1990年 | 866篇 |
1989年 | 777篇 |
1988年 | 779篇 |
1987年 | 716篇 |
1986年 | 743篇 |
1985年 | 797篇 |
1984年 | 632篇 |
1983年 | 550篇 |
1982年 | 415篇 |
1979年 | 663篇 |
1978年 | 501篇 |
1977年 | 406篇 |
1976年 | 391篇 |
1975年 | 555篇 |
1974年 | 689篇 |
1973年 | 700篇 |
1972年 | 547篇 |
1971年 | 513篇 |
1970年 | 468篇 |
1969年 | 465篇 |
1968年 | 617篇 |
1967年 | 543篇 |
1966年 | 540篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
Roderick P. McDonald 《Psychometrika》1962,27(2):203-206
A general formulation of the latent structure principle is suggested, from which it is possible to derive Lazarsfeld's accounting equations in their most general form. The basic equations of Gibson's latent profile model can thence be derived in a single step. 相似文献
953.
954.
Shimp CP 《Journal of the experimental analysis of behavior》1967,10(1):57-65
When a pigeon's choices between two keys are probabilistically reinforced, as in discrete trial probability learning procedures and in concurrent variable-interval schedules, the bird tends to maximize, or to choose the alternative with the higher probability of reinforcement. In concurrent variable-interval schedules, steady-state matching, which is an approximate equality between the relative frequency of a response and the relative frequency of reinforcement of that response, has previously been obtained only as a consequence of maximizing. In the present experiment, maximizing was impossible. A choice of one of two keys was reinforced only if it formed, together with the three preceding choices, the sequence of four successive choices that had occurred least often. This sequence was determined by a Bernoulli-trials process with parameter p. Each of three pigeons matched when p was ½ or ¼. Therefore, steady-state matching by individual birds is not always a consequence of maximizing. Choice probability varied between successive reinforcements, and sequential statistics revealed dependencies which were adequately described by a Bernoulli-trials process with p depending on the time since the preceding reinforcement. 相似文献
955.
C P Shimp 《Journal of the experimental analysis of behavior》1967,10(5):425-434
Five contingencies were superimposed successively on a variable-interval schedule of reinforcement. In each of the resulting conditions, a different short, interresponse time was reinforced and an interresponse-time distribution was obtained from each of three pigeons. The lower bound of the reinforced interresponse times ranged from 0.3 to 2.4 sec. The resulting distributions were combined, according to a rationale based upon concurrent operants, induction, and a property of variable-interval schedules, to describe the interresponse-time distributions from a variable-interval schedule. 相似文献
956.
Recall of dreams and the probability of stage 1-REM sleep 总被引:1,自引:0,他引:1
957.
958.
Transpositions in short-term memory 总被引:1,自引:0,他引:1
B B Murdock 《Journal of experimental psychology. General》1967,74(1):137-143
959.
960.
James M. Richards Leonard P. Rand Lorraine M. Rand 《Journal of counseling and development : JCD》1967,45(10):987-992
This study examines the geographical distribution of various junior college characteristics. Scores for 6 factors or categories of college characteristics, identified in earlier ACT research, were computed for each of 581 accredited junior colleges. When these junior colleges were classified and analyzed by geographical region, significant differences were found among regions on all 6 factors—Cultural Affluence (or Private Control), Technological Specialization, Size, Age (or Conventionalism), Transfer Emphasis, and Business Orientation (or High Cost). The regional differences are discussed and implications are suggested for research and counseling as well as for junior college planning. 相似文献