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   1260篇
  免费   172篇
  国内免费   22篇
  2024年   1篇
  2023年   42篇
  2022年   6篇
  2021年   29篇
  2020年   55篇
  2019年   73篇
  2018年   69篇
  2017年   57篇
  2016年   69篇
  2015年   37篇
  2014年   44篇
  2013年   146篇
  2012年   21篇
  2011年   23篇
  2010年   34篇
  2009年   44篇
  2008年   64篇
  2007年   78篇
  2006年   78篇
  2005年   71篇
  2004年   53篇
  2003年   30篇
  2002年   45篇
  2001年   24篇
  2000年   38篇
  1999年   37篇
  1998年   21篇
  1997年   27篇
  1996年   9篇
  1995年   20篇
  1994年   12篇
  1993年   8篇
  1992年   10篇
  1991年   14篇
  1990年   16篇
  1989年   7篇
  1988年   12篇
  1987年   7篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   4篇
  1980年   1篇
  1979年   2篇
  1978年   3篇
  1977年   4篇
  1976年   2篇
  1975年   3篇
排序方式: 共有1454条查询结果,搜索用时 15 毫秒
991.
Abstract. Fritjof Capra's The Tao of Physics , one of several popularizations paralleling Eastern mysticism and modern physics, is critiqued, demonstrating that Capra gives little attention to the differing philosophies of physics he employs, utilizing whatever interpretation suits his purposes, without prior justification. The same critique is applied and similar conclusions drawn, about some recent attempts at relating theology and physics. In contrast, we propose the possibility of maintaining a cogent relationship between these disciplines by employing theological hypotheses to account for aspects of physics that are free from interpretive difficulties, such as the ability to create mathematical structures with extraordinary predictive success.  相似文献   
992.
Pigeons, trained to discriminate phencyclidine from saline under a procedure requiring the bird to track the location of a color, received cumulative doses of phencyclidine, pentobarbital, or d-amphetamine with a variety of schedules of reinforcement in effect (across phases). When the same second-order schedules were used to reinforce responding after either saline or phencyclidine administration, stimulus control by phencyclidine did not depend on the schedule parameter. When different second-order schedules were used that biased responding toward the phencyclidine-correlated key color, pigeons responded on the phencyclidine-correlated key at lower doses of phencyclidine and pentobarbital than when the second-order schedule biased responding toward the saline key color. A similar but less marked effect was obtained with d-amphetamine. Attempts to produce bias by changing reinforcement magnitude (duration of food availability) were less successful. A signal-detection analysis of dose-effect curves for phencyclidine under two of the second-order schedules employed suggested that at low doses of phencyclidine, response bias is a major determinant of responding. As doses were increased, position preferences occurred and response bias decreased; at higher doses both response bias and position preference decreased and discriminability increased. With low doses of pentobarbital, responding again was biased but increasing doses produced position preference with only small increases in discriminability. At low doses of d-amphetamine responding also was biased, but bias did not decrease consistently with dose nor did discriminability increase. These experiments suggest that the schedule of reinforcement can be used to bias responding toward or away from making the drug-correlated response in drug discrimination experiments, and that signal-detection analysis and analysis of responding at a position can be used to separate the discriminability of the drug state from other effects of the drug on responding.  相似文献   
993.
Three rats were exposed to a second-order schedule in which fixed-interval components ended either with food or with a brief stimulus that was never paired with food. Food and the brief stimulus occurred in a random sequence (variable-ratio 2 overall schedule). Another three rats were exposed to a similar second-order schedule, the only difference being that the food or the stimulus was presented independently of operant behavior (fixed-time components). The three rats exposed to the fixed-interval components licked at a water spout after each food presentation. These rats also licked in the intervals after the brief stimulus. Although the discriminative properties of food and of the brief stimulus were identical in relation to subsequent reinforcement, licking after the stimulus was less than after food. The three rats exposed to the second-order schedules with fixed-time components also licked at the water spout after food, but these rats did not lick consistently after brief stimulus presentations.  相似文献   
994.
Richard Busse 《Zygon》1998,33(1):131-145
Historian James Gilbert argues that the dialogue between science and religion is an important dynamic in the creation of contemporary American culture. He traces the dialogue not only in the confines of the academic world but also in popular culture. The science-religion dialogue reveals a basic tension between the material and the spiritual that helps define the core of the American psyche: fascination with material progress yet commitment to traditional religious beliefs. Gilbert's cultural narrative traces the dialogue in a unique way because of the attention given to popular renditions of science and religion in evangelical films used by the military, in televised science programs, in science-fiction literature, and at the Seattle World's Fair in 1962. Gilbert suggests that the discussion between science and religion is significant because it is part of the process of creating new cultural structures necessitated by social, scientific, and technological developments. The tensions between religiously informed commonsense science and professional science work to create new cultural forms in a democratic society. Religion and science in dialogue are part of the process of cultural creation. Dogmatism on the part of either scientists or religionists is countered by the democratic process itself.  相似文献   
995.
996.
现代医学的时代特征与医学的应当   总被引:5,自引:1,他引:4  
21世纪的医学将真正从生物医学发展为人的医学,医学文化将是科学文化与人文文化的统一,医学将更加社会化,国际化,信息化,市场化,生态伦理化和多元化,医学目的也必将多元化。医学是时代的医学,但医学在走向人学。  相似文献   
997.
The ideal of scientific openness — i.e. the idea that scientific information should be freely accessible to interested parties — is strongly supported throughout the scientific community. At the same time, however, this ideal does not appear to be absolute in the everyday practice of science. In order to get the credit for new scientific advances, scientists often keep information to themselves. Also, it is common practice to withhold information obtained in commissioned research when the scientist has agreed with his or her employer to do so. The secrecy may be intended for ever, as in the military area, but also temporarily until a patent application has been made. The paper explores to what extent such secrecy is undesirable, as seems to be suggested by the ideal of scientific openness. Should this ideal be interpreted as having certain exceptions which make the above-mentioned practices acceptable? Are there, on closer inspection, good arguments for the ideal of scientific openness, and for officially upholding it? Possible versions of the ideal of scientific openness are explored and the issue is found to be rather complex, allowing for wide variations depending on the acting parties, beneficiaries, types of information and moral requirements involved. We conclude that the arguments usually given in favour of this ideal are weaker than what seems to be generally believed, and that, on closer inspection, they leave plenty of room for exceptions to it. These exceptions only partly cover the actual practice of withholding scientific information, and there may still be good reason to advocate, teach and enforce the ideal of scientific openness within the scientific community.  相似文献   
998.
Rats' lever pressing produced tokens according to a 20-response fixed-ratio schedule. Sequences of token schedules were reinforced under a second-order schedule by presentation of periods when tokens could be exchanged for food pellets. When the exchange period schedule was a six-response fixed ratio, patterns of completing the component token schedules were bivalued, with relatively long and frequent pauses marking the initiation of each new sequence. Altering the exchange period schedule to a six-response variable ratio resulted in sharp reductions in the frequency and duration of these initial pauses, and increases in overall rates of lever pressing. These results are comparable to those ordinarily obtained under simple fixed-ratio and variable-ratio schedules.  相似文献   
999.
Finn  V.K. 《Studia Logica》2000,66(2):205-213
The article gives a short account of V.A. Smirnovs scientific biography, including his work in Tomsk University in Siberia and in the Department of Logic of the Institute of Philosophy in Moscow.  相似文献   
1000.
Feminist contributions to the science curricula in higher education constitute invaluable but often overlooked resources for truly effective communication about science. Here I share a sampling of feminist science studies and discuss the origins of this effort to create inclusive and less biased science curricula that serve all students and citizens. Challenges from scientists center on assumptions and values about the appropriate relationship between science and politics, while challenges from educators extend to assumptions about how science has been taught. Currently, national and local curriculum transformation efforts are producing useful insights and materials. I want to thank Jinnie Garrett for inviting me to participate in the very exciting conference (Communicating Science held at Hamilton College, Clinton, NY, USA, 3–5 October 1998) and for her encouragement in preparing this paper. I also want to thank Joan Schulz and Patricia Brown for the important discussions and assistance contributing to this work.  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