首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   59962篇
  免费   2336篇
  国内免费   23篇
  2019年   612篇
  2018年   869篇
  2017年   904篇
  2016年   975篇
  2015年   731篇
  2014年   858篇
  2013年   4227篇
  2012年   1605篇
  2011年   1643篇
  2010年   1070篇
  2009年   993篇
  2008年   1516篇
  2007年   1445篇
  2006年   1303篇
  2005年   1188篇
  2004年   1144篇
  2003年   1095篇
  2002年   1123篇
  2001年   1780篇
  2000年   1734篇
  1999年   1308篇
  1998年   630篇
  1997年   592篇
  1996年   582篇
  1992年   1230篇
  1991年   1176篇
  1990年   1168篇
  1989年   1047篇
  1988年   1049篇
  1987年   1008篇
  1986年   1067篇
  1985年   1128篇
  1984年   898篇
  1983年   805篇
  1982年   572篇
  1981年   585篇
  1979年   1007篇
  1978年   713篇
  1977年   655篇
  1976年   657篇
  1975年   863篇
  1974年   1033篇
  1973年   1094篇
  1972年   891篇
  1971年   875篇
  1970年   826篇
  1969年   846篇
  1968年   1102篇
  1967年   980篇
  1966年   935篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
When day-old chicks are trained on a passive avoidance task there is enhanced synthesis of glycoproteins. Bilateral intracerebral injections of 20 mumole of 2-deoxygalactose (2-D-gal), administered just before and just after training on the task, produce amnesia for the avoidance. Amnesia develops slowly over the first hour and persists for at least 24 h subsequently. If 2-D-gal injections are administered 4 h prior to the training or delayed for 3 h after training, no amnesia occurs. Apart from a brief initial suppression of pecking following injection there are no effects of 2-D-gal on other observed behaviors of the birds. Within the first hour this dose of 2-D-gal inhibits [3H]fucose incorporation into acid-insoluble material by 26% (or 68%, calculated relative to free pool fucose). The amnestic effect of 2-D-gal is not shown by galactose, glucose, fucose, or 2-D-glucose. Injecting 40 mumole of galactose simultaneously with the 2-D-gal abolishes the 2-D-gal-induced amnesia; 40 mumole of fucose, however, does not abolish the amnesia. The utility of 2-D-gal as an agent for analyzing the role of glycoproteins in memory formation is discussed.  相似文献   
922.
In four experiments we examined the effect of an irrelevant drive on classical conditioning with food and water. In the first experiment the irrelevant drive weakened the conditioned response in extinction. In Experiments 2 and 3, this suppressive effect was found also in acquisition. Furthermore, the presence of an irrelevant drive during nonreinforced presentations of the conditioned stimulus was found to protect the conditioned response from extinction. Experiment 4 showed that the depressive effect of the irrelevant drive is manifested only when the relevant drive is present. Taken together, these results suggest that an irrelevant drive can influence conditioned responding by modulating the representation of the unconditioned stimulus.  相似文献   
923.
924.
When listeners hear a sinusoidal replica of a sentence, they perceive linguistic properties despite the absence of short-time acoustic components typical of vocal signals. Is this accomplished by a postperceptual strategy that accommodates the anomalous acoustic pattern ad hoc, or is a sinusoidal sentence understood by the ordinary means of speech perception? If listeners treat sinusoidal signals as speech signals however unlike speech they may be, then perception should exhibit the commonplace sensitivity to the dimensions of the originating vocal tract. The present study, employing sinusoidal signals, raised this issue by testing the identification of target /bVt/, or b-vowel-t, syllables occurring in sentences that differed in the range of frequency variation of their component tones. Vowel quality of target syllables was influenced by this acoustic correlate of vocal-tract scale, implying that the perception of these nonvocal signals includes a process of vocal-tract scale, implying that the perception of these nonvocal signals includes a process of vocal-tract normalization. Converging evidence suggests that the perception of sinusoidal vowels depends on the relation among component tones and not on the phonetic likeness of each tone in isolation. The findings support the general claim that sinusoidal replicas of natural speech signals are perceptible phonetically because they preserve time-varying information present in natural signals.  相似文献   
925.
We investigated the psychological reality of the concept of orthographical depth and its influence on visual word recognition by examining naming performance in Hebrew, English, and Serbo-Croatian. We ran three sets of experiments in which we used native speakers and identical experimental methods in each language. Experiment 1 revealed that the lexical status of the stimulus (high-frequency words, low-frequency words, and nonwords) significantly affected naming in Hebrew (the deepest of the three orthographies). This effect was only moderate in English and nonsignificant in Serbo-Croatian (the shallowest of the three orthographies). Moreover, only in Hebrew did lexical status have similar effects on naming and lexical decision performance. Experiment 2 revealed that semantic priming effects in naming were larger in Hebrew than in English and completely absent in Serbo-Croatian. Experiment 3 revealed that a large proportion of nonlexical tokens (nonwords) in the stimulus list affects naming words in Hebrew and in English, but not in Serbo-Croatian. These results were interpreted as strong support for the orthographical depth hypothesis and suggest, in general, that in shallow orthographies phonology is generated directly from print, whereas in deep orthographies phonology is derived from the internal lexicon.  相似文献   
926.
A considerable percentage of depressed patients do not respond to antidepressive treatment. Early indicators of prognosis are needed. The aims of this study are to examine (a) whether the interpersonal behavior of patients and psychiatrist, as assessed by means of direct observation of behavior during a baseline clinical interview, might have predictive value with respect to therapeutic outcome and (b) which predictive potency measures of psychomotor activation, as assessed by less refined methods, such as global clinical judgment, might have. In the analysis used, speech-pause behavior was taken as the basic structure of the interaction. The relations of other behaviors such as looking and hand and head movement with this structure were determined. Evidence is presented that in a group of 31 depressives, improvement after a period of 10 weeks was related to observed behaviors during a baseline interview. The behaviors of the patients are interpreted as relational or nonrelational. The relational behaviors (i.e., looking yesnodding, gesturing) occur less in patients who will improve, whereas the nonrelational behaviors (i.e., intensive body touching, head movements) occur more in these patients. The nonrelational behaviors are presumed to be indicative of the state of arousal. The predictive potency of these variables could not be explained by their relationship with the baseline severity of depression, which in itself also predicted improvement. Moreover, global clinical assessment of psychomotor activation (i.e., retardation and agitation) could not be related to outcome.  相似文献   
927.
This article presents Albert Ellis' personal responses to the Survey of Rational-Emotive Therapists and his answers to a number of questions that the first and second authors asked Ellis regarding some of his responses. Ellis also commented on how adequately he thought the results of the survey appeared to represent the current philosophies and practices of RET.  相似文献   
928.
The infant's first natural response when faced with opposition or when he opposes others' actions is to cry. As this kind of behavior becomes ineffective, the responses of the individuals with which he interacts force him to adopt more conventional — especially verbal — patterns of arguing, leading him to rational argumentation. The purpose of the present paper is to observe progressions in children's earliest verbal arguments and to see how and when they learn to adjust their strategies for different kinds of opponents (peers; parents; other adults). In order to examine the emergence of such persuasive strategies, and their distribution according to the different categories of opponents, systematic audiotape recordings of two Spanish-speaking girls between 2 and 3 years were analyzed. The data suggest that, although there were some differences in how the girls argued with parents versus peers, they were only beginning to adjust their speech to make it appropriate for one or the other type of listener. In general, they resorted to one dominant strategy for all listeners (insist, repeat, cry, scream, ...). Each girl, however, developed a small number of less frequently used strategies that she reserved for a subcategory of opponents. For example, one of them, Nancy, only threatened and insulted peers, while the other, Marisa, only used please and a temporizing strategy with parents. The girls used less adaptive, more agressive strategies (e.g. threats and insults) with their peers. With one exception, all of the girls' moves were self-centered. In fact, the girls had not yet reached the stage of rational argumentation.  相似文献   
929.
This study compared the predictive validity of two types of overall assessment center ratings (clinical and mechanical) and two types of performance ratings (supervisor and subordinate). Data were gathered on approximately 50 law enforcement agency managers over a four-year time span. Results indicated that clinical predictions were not significantly better than mechanical ones and that prior performance ratings were better predictors of future performance ratings than were assessment centers. Further, dimension ratings within the assessment center were found to be unrelated to ratings of the same dimensions on the job four years later, supporting the notion of subtle criterion contamination (Klimoski & Strickland, 1977) and raising questions about the central assumptions underlying the assessment center approach.  相似文献   
930.
This paper describes three types of traps or collusive marital agreements-incompetence traps, complementarity traps, and success traps-in which the mates renounce or forgo competent functioning in vital areas of marital roles and experience. It is suggested that responsible clinical work with the couple should include a careful evaluation of such traps and the potential breakdown or dysfunction inherent in each one, and a decision as to whether or not to attempt therapeutic penetration into such collusive agreements even before the couple complain directly about their arrangement.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号