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   19716篇
  免费   1757篇
  国内免费   1302篇
  22775篇
  2024年   36篇
  2023年   320篇
  2022年   311篇
  2021年   399篇
  2020年   716篇
  2019年   804篇
  2018年   714篇
  2017年   863篇
  2016年   824篇
  2015年   531篇
  2014年   712篇
  2013年   2231篇
  2012年   456篇
  2011年   616篇
  2010年   457篇
  2009年   723篇
  2008年   916篇
  2007年   913篇
  2006年   868篇
  2005年   774篇
  2004年   652篇
  2003年   551篇
  2002年   519篇
  2001年   317篇
  2000年   298篇
  1999年   252篇
  1998年   207篇
  1997年   163篇
  1996年   144篇
  1995年   130篇
  1994年   117篇
  1993年   97篇
  1992年   73篇
  1991年   54篇
  1990年   53篇
  1989年   32篇
  1988年   46篇
  1985年   372篇
  1984年   418篇
  1983年   348篇
  1982年   457篇
  1981年   445篇
  1980年   444篇
  1979年   398篇
  1978年   453篇
  1977年   355篇
  1976年   359篇
  1975年   273篇
  1974年   278篇
  1973年   236篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
In contrast to the opinion of numerous authors (e.g. R. Rudner, P. Kitcher, L. R. Graham, M. Dummett, N. Chomsky, R. Lewontin, etc.) it is argued here that the formation of opinion in science should be greatly insulated from political considerations. Special attention is devoted to the view that methodological standards for evaluation of scientific theories ought to vary according to the envisaged political uses of these theories.I wish to thank the Alexander von Humboldt Foundation for having supported the work on this paper.  相似文献   
22.
This study of 20 ‘white-collar’ workers aged 20–30 measured motivation, enjoyment and access to various categories of experience in both work and leisure, and examined their relationship with psychological well-being on a number of dimensions. The method used a short questionnaire, psychological scales and the innovatory ‘experience sampling methodology’ (ESM) where respondents answer questions in a diary on the receipt of a signal from a pre-programmed watch or radio pager eight times a day for 1 week. The results show, in line with other studies, that intrinsic motivation in daily life is correlated with happiness but that, not previously reported, when motivation at work is examined both extrinsic motivation and instances where a person had to do the activity but did not wish to be doing something else, i.e. ‘positive motivational change’, are correlated with positive aspects of psychological well-being, while instances where a person wanted to do the activity but wished to be doing something else, i.e. ‘negative motivational change’, correlated with negative aspects. The results also show that enjoyment in both work and leisure correlates with aspects of psychological wellbeing; and that macro ‘flow’ experiences, where high skills and high challenges are perceived as equal, are enjoyable and interesting and come primarily from work. The study also shows that categories of experience considered important for psychological well-being and deemed to come primarily from work can be obtained in leisure. The results are discussed in the context of person—situation interactions and processes, and it is advocated that these should be studied in a variety of samples.  相似文献   
23.
A study that involved parents as reading tutors was carried out at home during the summer with four elementary children, three with learning disabilities. One purpose was to determine the effects of tutoring in the basal reader on reading rates at home. Another purpose was to determine potential generalization effects as a result of parent tutoring on different academic tasks at home and, later at school, on different and similar tasks. A combination multiple-baseline and reversal design tested for replication and generalization effects. Increases in correct rates were noted for the targeted variables across conditions. The results indicated that parents tutoring with school basal texts during the summer produced marked increases in reading rates that generalized at home to different academic tasks and at school to different and similar tasks. This suggests that parents, when using specific tutoring procedures, can increase their children's academic skills.  相似文献   
24.
Mary Anne Warren's claim that there is room for only one person with full and equal rights inside a single human skin ([1], p. 63) calls attention to the vast range of moral conflict engendered by assigning full basic moral rights to fetuses. Thereby, it serves as a goad to thinking about conflicts between pregnant women and their fetuses in a way that emphasizes relationships rather than rights. I sketch out what a care orientation might suggest about resolving gestational conflicts. I also argue that the care orientation, with its commitment to the significance of the partial and the particular, cannot be absorbed within standard, impartialist moral theory.  相似文献   
25.
Genetic counselors have participated in the Michigan Newborn Screening Program on a contractual basis since 1988. Their role includes newborn screening education and training, newborn nursery site visits, and monitoring newborn screening in hospitals. Their impact has been to improve the quality of newborn screening services by reducing errors and increasing completion of data fields on newborn screening cards, improving hospital nursery cooperation and problem solving, and enhancing health department response to specific problems.  相似文献   
26.
A new method for determining the minimum number of observations per subject needed to achieve a specific generalizability coefficient is presented. This method, which consists of a branch-and-bound algorithm, allows for the employment of constraints specified by the investigator.  相似文献   
27.
We propose a method for detecting influential observations in iterative principal factor analysis. For this purpose we derive the influence functionsI(x; LL T ) andI(x; ) for the common variance matrixT =LL T and the unique variance matrix , respectively, in the common factor decomposition =LL T + . A numerical example is given for illustration.The authors are grateful to Tomoyuki Tarumi and Atsuhiro Hayashi for their kind permission to use their software Seto/B for drawing Figures 1 and 2 and to anonymous reviewers for comments on the paper.  相似文献   
28.
Hwe Ik Zhang 《Zygon》1989,24(4):447-456
Abstract. The position and role of humanity in the world of life is examined in the light of the ontological structure of life itself. This problem is approached by considering the possible units of life representing various modes of life phenomena. I argue that the only meaningful unit of life without interposing some special external conditions is "global life" framed in a star-planet system. Any other possible unit of life exhibited by various kinds of individuals is conditional in the sense that it would leave out an essential part as "co-life." The relationship between human being and the global life should be understood in this general scheme of individual and global life. It is emphasized, however, that human being occupies a unique position in global life in the sense that humanity can promote either a cancerous situation or a healthy higher-order enhancement of the global life.  相似文献   
29.
Philip Clayton 《Zygon》1989,24(3):315-334
Abstract. Imre Lakatos's philosophy of science can provide helpful leads for theological methodology, but only when mediated by the disciplines that lie between the natural sciences and theology. The questions of relativism and truth are used as indices for comparing disciplines, and Lakatos's theory of natural science is taken as the starting point. Major modifications of Lakatos's work are demanded as one moves from the natural sciences, through economics, the interpretive social sciences, literary theory, and into theology. Although theology may consist of Lakatosian research programs, it also includes programs of interpretation and programs for living. This conclusion must influence our definition of theological truth and our assessment of theological relativism.  相似文献   
30.
Research on reaching, tracking, and catching in the pigeon has been hampered by limitations of technology. A new system was developed in which the target was a small rectangle presented on a video display terminal and the pecking response was detected with touch technology. The target moved up and down vertically with sinusoidal velocity. A coincidence between the location of the pigeon's beak and the cursor produced reinforcement. The pigeon pecked ahead and behind the target, but most pecks occurred behind the target so the dominant tracking strategy was lagging. The pigeon was adept at “catching” the target at many locations throughout the trajectory. Transfer of motor learning was tested on probe trials during which the trajectory changed from vertical to horizontal. On transfer trials the pigeons' dominant pattern of pecking immediately shifted from vertical to horizontal. The motor skill displayed by the pigeons was flexible and adaptive, suggesting that the pigeons had learned to track the cursor.  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