全文获取类型
收费全文 | 42262篇 |
免费 | 1775篇 |
国内免费 | 11篇 |
专业分类
44048篇 |
出版年
2020年 | 428篇 |
2019年 | 550篇 |
2018年 | 771篇 |
2017年 | 775篇 |
2016年 | 792篇 |
2015年 | 577篇 |
2014年 | 707篇 |
2013年 | 3101篇 |
2012年 | 1273篇 |
2011年 | 1360篇 |
2010年 | 818篇 |
2009年 | 772篇 |
2008年 | 1160篇 |
2007年 | 1127篇 |
2006年 | 1060篇 |
2005年 | 934篇 |
2004年 | 911篇 |
2003年 | 822篇 |
2002年 | 869篇 |
2001年 | 1343篇 |
2000年 | 1250篇 |
1999年 | 938篇 |
1998年 | 481篇 |
1996年 | 391篇 |
1992年 | 726篇 |
1991年 | 725篇 |
1990年 | 704篇 |
1989年 | 709篇 |
1988年 | 706篇 |
1987年 | 655篇 |
1986年 | 658篇 |
1985年 | 719篇 |
1984年 | 592篇 |
1983年 | 530篇 |
1982年 | 457篇 |
1981年 | 417篇 |
1979年 | 650篇 |
1978年 | 462篇 |
1977年 | 400篇 |
1976年 | 440篇 |
1975年 | 549篇 |
1974年 | 631篇 |
1973年 | 671篇 |
1972年 | 537篇 |
1971年 | 503篇 |
1970年 | 482篇 |
1969年 | 520篇 |
1968年 | 634篇 |
1967年 | 531篇 |
1966年 | 543篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
161.
162.
163.
164.
GEORGE N. SCHLESINGER 《Metaphilosophy》1988,19(3-4):282-293
165.
166.
167.
A E Puente 《Perceptual and motor skills》1988,66(2):639-642
MMPI profiles of 22 chronic arthritic patients were compared to 22 control pain (nonorganic) patients. While elevations were noted in the HS, D, and Hy scales for the rheumatoid patients, the over-all profiles differed from controls on the PA scale. 相似文献
168.
Multiunit activity (MUA) was recorded chronically in the hippocampus (CA3) and the medial geniculate body (mMG) during habituation to a tone followed by conditioning (tone paired with footshock) or pseudoconditioning (tone/footshock unpaired) in rats previously trained in a lever-pressing for food task (VI 60). In the conditioned group pairing tones with footshocks rapidly induced an increase in the initial CS-evoked response in the mMG, followed by the emergence of a hippocampal response and a marked conditioned suppression of lever-pressing to the tone. In contrast, in the pseudoconditioned group, the stimulus induced only transient cellular changes in the hippocampus and in the mMG, while no behavioral suppression to the tone could be seen. Moreover, presentations of the CS 45 days later induced multiunit and behavioral responses in both structures, only in the conditioned group. These results are used for discussion of the role of learning-induced changes in the sensory structure (mMG) as compared with changes in an associative structure (hippocampus), during acquisition and retention of a conditioned response. 相似文献
169.
For 3 consecutive days cockroaches (Periplaneta americana) were exposed to either escapable, inescapable, or no shock in an escape task. Twenty-four hours later they were tested in a shuttlebox escape task. There were reliable differences between escapable and inescapable animals and between inescapable and control animals in both escape latencies and the number of failures to escape. 相似文献
170.
Previously we (Bruno & Cutting, 1988) explored the perception of spatial relations among objects laid out in a computer-generated environment. In his commentary on our article, Massaro (1988) raised several issues. The most important is from his reanalysis, which indicated that--because of a subadditive trend in the results--additive and multiplicative strategies fit our data in Experiment 1 about equally well. In reply, we performed a different analysis. Results corroborate subadditivity--and hence multiplicative information combination--in Experiment 1 but provide no evidence for it in Experiments 2 and 3. On the whole, then, the results still support additivity more strongly than any other combination rule and thus support our notion of minimodularity. 相似文献