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   14481篇
  免费   808篇
  国内免费   5篇
  2020年   256篇
  2019年   204篇
  2018年   316篇
  2017年   350篇
  2016年   360篇
  2015年   267篇
  2014年   316篇
  2013年   1340篇
  2012年   450篇
  2011年   469篇
  2010年   304篇
  2009年   299篇
  2008年   424篇
  2007年   373篇
  2006年   383篇
  2005年   291篇
  2004年   286篇
  2003年   249篇
  2002年   288篇
  2001年   445篇
  2000年   438篇
  1999年   315篇
  1998年   152篇
  1996年   157篇
  1995年   148篇
  1993年   138篇
  1992年   273篇
  1991年   279篇
  1990年   256篇
  1989年   257篇
  1988年   241篇
  1987年   228篇
  1986年   209篇
  1985年   203篇
  1984年   187篇
  1983年   157篇
  1982年   152篇
  1979年   184篇
  1978年   151篇
  1977年   154篇
  1975年   177篇
  1974年   184篇
  1973年   208篇
  1972年   170篇
  1971年   157篇
  1970年   145篇
  1969年   150篇
  1968年   196篇
  1967年   160篇
  1966年   167篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Some properties are discussed of regular polygons that may result from angular homeostatic processes in stable orbit. To characterize these homeostatic polygons we need to discuss the winding number, the sidedness (integer, fractional and irrational), multiplicity, envelopes, and density. A regular (i.e., equilateral, equiangular) polygon may be closed in one revolution about its unique center, in multiple revolutions, or not at all. A homeostatic polygon can be generated only if all vertices are included in a single polygon, which occurs if and only if the number of vertices and the number of revolutions required to complete the polygon are relatively prime. For the homeostatic polygon to have a finite number of sides (without repeating itself) the angle subtended by any two successive vertices at the center must be a rational multiple of 2. Biological implications of these properties are illustrated.  相似文献   
142.
143.
A sample of physician-referred chronic insomniacs was randomly allocated to either progressive relaxation, stimulus control, paradoxical intention, placebo or no treatment conditions. Treatment process and outcome were investigated in terms of mean and standard deviation (night to night variability) measures of sleep pattern and sleep quality. Only active treatments were associated with significant improvement, but the nature of treatment gains varied. In particular, stimulus control improved sleep pattern, whereas relaxation affected perception of sleep quality. All improvements were maintained at 17 month follow-up. Results are discussed with reference to previous research and guidelines are given for clinical practice.  相似文献   
144.
145.
The purpose of this work is to explore the phenomenon of negativism and the analyst's response to it during the course of analytic work with a patient in whom negativism is a central behavioral pattern. Melville's short story, "Bartleby the Scrivener," describing in telling detail the response of a sympathetic lawyer to profound and pervasive negativism in his legal scribe, is discussed as a literary analogy to the analyst-analysand dyad. Aspects of the concept of negativism within psychoanalysis are discussed. The potential usefulness of understanding certain unexpected countertransference responses to pervasive negativism is explored, as this is a relatively neglected area of psychoanalytic technique. A case is presented describing the analysis of a patient whose character, like Bartleby's, is a mixture of profound negativism along with schizoid, obsessional, and masochistic elements.  相似文献   
146.
In this study the Revised Fear Survey Schedule for Children was administered to 138 hearing-impaired and 134 normally hearing youths. Although both groups expressed fear of potentially dangerous stimuli, significant differences in responding were evident towards other kinds of stimuli. Whereas hearing children were more fearful of failure and criticism, the hearing-impaired children were more afraid of the unknown, injury and small animals. Girls reported significantly greater levels of fear than boys thus confirming a well established research finding. Further, significant interactions were found between hearing status and gender. In contrast to previous findings, age was not related to self-reports of fear.  相似文献   
147.
The purpose of this study was to compare our structured research-based version of marital therapy from a social learning perspective with a clinically flexible version of the same treatment where treatment plans were individually-based and there was no specific number of treatment sessions. Thirty distressed married couples were randomly assigned to one of these two treatments. Assessment of outcome was based on global marital satisfaction, spouse reports of functioning in specific areas, and direct observational measures of communication. At posttest there were no differences in efficacy between structured and flexible treatments, although both treatments led to significant improvements. At a 6-month follow-up couples treated with the structured format were more likely to have deteriorated and flexibly treated couples were more likely to have maintained their treatment gains.  相似文献   
148.
Believability and syllogistic reasoning   总被引:4,自引:0,他引:4  
In this paper we investigate the locus of believability effects in syllogistic reasoning. We identify three points in the reasoning process at which such effects could occur: the initial interpretation of premises, the examination of alternative representations of them (in all of which any valid conclusion must be true), and the "filtering" of putative conclusions. The effect of beliefs at the first of these loci is well established. In this paper we report three experiments that examine whether beliefs have an effect at the other two loci. In experiments 1 and 2 subjects drew their own conclusions from syllogisms that suggested believable or unbelievable ones. In the third experiment they evaluated conclusions that were presented to them. The data show that beliefs both affect the examination of alternative models and act as a filter on putative conclusions. We conclude by showing how some types of problem and some problem contents make the existence of alternative models more obvious than others.  相似文献   
149.
Although there has been a considerable amount of research on simultaneous and successive processing (Luria's second functional unit) by Das and others, there have been relatively few investigations into the measurement of attention and planning (the first and third functional units, respectively). The purpose of this investigation was to examine the factorial validity of tasks designed to measure cognitive processing in each of Luria's three functional units. A sample of 112 normal fourth- and fifth-grade students were administered nine experimental tasks chosen or developed according to the theoretical components of planning, attention, simultaneous, and successive processes. Principal factor analyses (orthogonal and oblique) with rotation of four factors resulted in solutions that closely matched the anticipated groupings based on a structural analysis of the tasks. General support for the feasibility of measurement of Luria's cognitive processing model, and the need to further develop and refine these and other experimental tasks, was obtained.  相似文献   
150.
A common error made by behavior genetics researchers is breeding two lines for differences in central arousal rather than for a specific behavioral feature. Two lines of rats (Riley, Freed, & Lester, 1976) were selectively bred for locomotor impairment in response to a subhypnotic dose (1.5 g/kg) of ethanol. These lines (designated "most affected" and "least affected") were compared in a variety of tests and showed differences in a number of phenotypic traits in addition to locomotor impairment to ethanol. The published findings have been interpreted in light of a hypothesis suggesting adventitiously selected differences in central arousal between the two lines. This interpretation showed that their usefulness as animal models of alcoholism is seriously compromised.  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