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   5051篇
  免费   290篇
  国内免费   2篇
  2023年   47篇
  2022年   42篇
  2021年   69篇
  2020年   109篇
  2019年   153篇
  2018年   169篇
  2017年   191篇
  2016年   185篇
  2015年   126篇
  2014年   170篇
  2013年   640篇
  2012年   233篇
  2011年   296篇
  2010年   149篇
  2009年   168篇
  2008年   235篇
  2007年   181篇
  2006年   177篇
  2005年   165篇
  2004年   197篇
  2003年   162篇
  2002年   136篇
  2001年   71篇
  2000年   70篇
  1999年   44篇
  1998年   65篇
  1997年   55篇
  1996年   53篇
  1995年   45篇
  1994年   42篇
  1993年   29篇
  1992年   49篇
  1991年   35篇
  1990年   40篇
  1989年   35篇
  1988年   40篇
  1987年   42篇
  1986年   38篇
  1985年   38篇
  1984年   47篇
  1983年   54篇
  1982年   32篇
  1981年   30篇
  1980年   40篇
  1979年   38篇
  1978年   30篇
  1977年   34篇
  1976年   30篇
  1975年   21篇
  1974年   24篇
排序方式: 共有5343条查询结果,搜索用时 15 毫秒
101.
Science asks that a theory state its basic terms and operations with economy and precision. Twenty-two terms and operations of Zuk's Go-Between Process are defined. It is desirable in science also to carefully distinguish among related theories. Go-Between Process and Structural-Strategic Family Therapy are related theories, and differences are described.  相似文献   
102.
This report describes the use of an animal model for testing the relationship between the effects of ingesting food additives and hyperactivity. Telomian × beagle hybrid dogs were chosen as subjects because this breed has been observed to exhibit behavior seen as analogous to the hyperactivity of children. Two studies were conducted by adding or deleting butylated hydroxyanisole and Food, Drug, and Cosmetic red dye number 40 to the diet of each dog. A test of sitting was performed to measure the level of activity. While a relationship was not observed between the ingestion of the additive and the level of activity, several issues pertaining to the use of the animal model became apparent. These issues and the use of animals for future research in this area are discussed.  相似文献   
103.
104.
In the 1940's two forms of intelligence, fluid and crystallized, were postulated. Active mental processing (WAIS performance subtests) were fluid while well learned abilities (WAIS verbal subtests) were crystallized. Brain damage was considered to affect fluid abilities more than crystallized. WAIS scores comparing normal and diffusely organically damaged subjects indicated that, as hypothesized, the verbal subtests were more affected than the performance subtests.  相似文献   
105.
The present studies assessed the degree of stimulus control exerted by S+ and S? without confoundings of stimulus novelty and stimulus ambiguity. In Experiment 1, rats were trained on two intercurrent simultaneous discrimination problems with nine times more training given on one than the other. Then the animals were given transfer tests with re-paired stimuli. The results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination. Experiment 2 provided a test of the possibility that the relative degree of control by S? varies with different amounts of training. Three groups were trained on two intercurrent simultaneous discrimination problems; each group was given 7, 11, or 15 times more training on one problem than the other. Then transfer tests were given with re-paired stimuli. Again the results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination.  相似文献   
106.
107.
The communication disorder in dialysis dementia is an integral feature of the syndrome. This report describes the communication disorder in a 67-year-old man over a period of 4 months from his admission to the hospital to his death. In the early stage of the syndrome, the most prominent feature was a speech problem, the characteristics of which may vary among cases. In the middle stage, it was difficult to distinguish among aphemia, aphasia, or a combination of dysarthria and confusional state. The severity of the problems in these stages was temporally related to the dialysis treatments. The final stage was characterized by constant mutism and was unrelated to the dialysis treatments. Death occurred 10 months after the communication problems emerged. Communication studies of dialysis dementia patients may offer a systematic method to monitor the course of the syndrome, its response to therapeutic trials, and a clinical model for the study of communication disorders in general.  相似文献   
108.
Presentence reports on 628 offenders were content analyzed. Regression analysis found that remorseful offenders received less severe sentences than non-remorseful offenders. Offenders convicted of minor offenses received more lenient sentences if they had used alcohol in conjunction with their crimes than if they did not use alcohol. The opposite was the case for offenders commiting serious crimes. Remorseful offenders with few prior alcohol-related convictions received less severe sanctioning than non-remorseful offenders with similar conviction records. In contrast, recidivists who were remorseful were dealt with more harshly than their non-remorseful counterparts.  相似文献   
109.
This study is concerned with the manner in which Western mathematics is assimilated by children raised in traditional African cultures. It was predicted that after an initial period of difficulty in learning school arithmetic, African children (Baoulé and Dioula from the Ivory Coast) acquire basic concepts, develop invented strategies, and make errors similar to those of American children. Further, it was predicted that Dioula children, since they are members of a commercial culture, perform at a somewhat higher level than the Baoulé, members of a farming culture which does not seem to stress computational activity. To investigate these hypotheses, American, Baoulé, and Dioula children at two age levels were given a variety of arithmetic problems involving basic skills (e.g., reading numbers), number knowledge (e.g., place value), and calculational abilities (e.g., written computation). The results showed that, in general, older African and American children (fifth- and sixth-graders) were quite similar in all respects. The only large and significant differences occurred in the case of younger children (second- and third-graders). At this level American children generally performed at a higher level than Africans, as predicted, and Dioula occasionally at a higher level than Baoulé, also as predicted. At the same time, qualitative aspects of African and American children's performance were similar: for example, both groups made the same types and proportions of errors in written calculations. The results generally support the hypotheses and can be explained in terms of both educational and cognitive factors.  相似文献   
110.
Motivating developmentally disabled children to participate in educational activities can be very difficult. This is especially true for children diagnosed autistic. Because there is some evidence to suggest that stimulus variation may influence motivation, the present study investigated the effects of constant vs. varied reinforcer presentation on correct responding and on-task behavior. Results from a reversal design showed declining trends in both correct responding and on-task behavior when the same reinforcer was consistently presented, whereas, varying the reinforcers produced significantly improved and stable responding. The results are discussed in relation to the literature on stimulus variation and its effects on responsivity.  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