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   8863篇
  免费   166篇
  国内免费   46篇
  2018年   22篇
  2014年   15篇
  2013年   14篇
  2012年   969篇
  2011年   1062篇
  2010年   257篇
  2009年   136篇
  2008年   806篇
  2007年   802篇
  2006年   778篇
  2005年   584篇
  2004年   558篇
  2003年   566篇
  2002年   435篇
  2001年   310篇
  2000年   387篇
  1999年   186篇
  1998年   43篇
  1997年   60篇
  1996年   28篇
  1995年   38篇
  1994年   36篇
  1993年   26篇
  1992年   33篇
  1991年   48篇
  1990年   40篇
  1989年   43篇
  1988年   41篇
  1987年   38篇
  1986年   37篇
  1985年   35篇
  1984年   24篇
  1983年   29篇
  1982年   27篇
  1981年   25篇
  1979年   13篇
  1978年   24篇
  1965年   17篇
  1964年   18篇
  1959年   19篇
  1958年   55篇
  1957年   53篇
  1956年   32篇
  1955年   34篇
  1954年   20篇
  1953年   22篇
  1952年   27篇
  1951年   25篇
  1950年   22篇
  1949年   19篇
排序方式: 共有9075条查询结果,搜索用时 31 毫秒
81.
Leikin S 《Ethics & behavior》1995,5(2):193-194, 196-199
Case vignette: sharing unanticipated genetic information. The Questor family has experienced an unusual number of malignancies in the past two generations and has been advised by an oncologist that the p53 oncogene known as Li-Fraumeni Syndrome may be present in the family genome. The option of predictive genetic testing has been raised and several branches of the family have chosen to undergo screening to determine whether they are at risk for cancer because of the gene. Roger and Liz Questor have arranged for screening of themselves and their three children, ages 12, 10, and 7. The couple has, by all appearances, been happily married for 14 years. None of the family members are found to carry the oncogene; however, the geneticist conducting the analyses has made an interesting incidental discovery. The 10-year-old child is not the biological progeny of Roger Questor. Although the 12-and 7-year-olds are clearly the biological children of the couple, it is evident that the 10-year-old born to Liz Questor was fathered by a person other than Roger. What are the ethical obligations of the geneticist with respect to any sharing or disclosure of the information that has been discovered incidentally? What course of action, if any, do you recommend?  相似文献   
82.
Scarr S 《Ethics & behavior》1994,4(2):147-155
The articles by Brooks-Gunn, Fisher, Hoagwood, Liss and Scott-Jones (all in this issue) present a panoply of real-world ethical issues in conducting scientific research on risky behaviors of children, adolescents, and their parents, particularly those from vulnerable populations. The universal, ethical principles of beneficence, justice, and respect for others are always applicable, but they do not resolve issues of child assent, parental consent, legal reporting requirements for illegal behaviors, and the special problems of studying risky behaviors in risky populations. Taken as a group, the articles raise some of the most interesting ethical problems that arise in developmental research. My discussion elaborates some issues and fails to resolve others. I hold the view that both science and ethics can be served by thoughtfully designed and implemented research on important social issues, but that the studies themselves cannot simultaneously solve the many societal problems of participants and be scientifically credible.  相似文献   
83.
The importance of consulting with other professionals to maintain acceptable standards of care is well documented in many health care professions. However, evidence indicates that many psychologists fail to utilize consultation when needed, and that consultation use varies along dimensions such as the education and training of the consultee, the type of setting, number of years in practice, and proximity to available consultants. In this article, we review the research on the use of consultation by psychologists as well as other health care professionals. We discuss the clinical, ethical, and legal implications of seeking consultation as a professional psychologist. Finally, a detailed and practical model for the regular use of consultation is given to improve the routine use of consultation in clinical practice.  相似文献   
84.
维特根斯坦在第一次世界大战的战壕中写完他的第一本书——《逻辑哲学论》,当时他在奥地利军队中服役.一系列精雕细刻的格言由一个复杂的排列体系联结起来,并且一切都按照从形而上学到形式逻辑的方向排列.此书被罗素誉为是一部杰作.人们很快就广泛认识到这本书的重要性,特别是通过石里克、卡纳普和魏斯曼,维也纳学派认识到了它的重要性.《逻辑哲学论》立刻使维特根斯坦在哲学家的神殿中占有了一席之地.《逻辑哲学论》是维特根斯坦自己出版的唯一的一本书.有一段时间他放弃哲学去当了一名小学教师,后来又在奥地利做一名建筑师,1929年他回到剑桥,在那里断断续续地工作一直到他1951年去世.他的思想交流实际上仅局限于课堂,他在由学生和同事组成的非常亲密的  相似文献   
85.
86.
87.
88.
The skill of rhythmically juggling a ball on a racket was investigated from the viewpoint of nonlinear dynamics. The difference equations that model the dynamical system were analyzed by means of local and nonlocal stability analyses. These analyses showed that the task dynamics offer an economical juggling pattern that is stable even for open-loop actuator motion. For this pattern, two types of predictions were extracted: (a) Stable periodic bouncing is sufficiently characterized by a negative acceleration of the racket at the moment of impact with the ball, and (b) a nonlinear scaling relation maps different juggling trajectories onto one topologically equivalent dynamical system. The relevance of these results for the human control of action was evaluated in an experiment in which subjects (N = 6) performed a comparable task of juggling a ball on a paddle. Task manipulations involved different juggling heights and gravity conditions of the ball. The following predictions were confirmed: (a) For stable rhythmic performance, the paddle's acceleration at impact is negative and fluctuations of the impact acceleration follow predictions from global stability analysis; and (b) for each subject, the realizations of juggling for the different experimental conditions are related by the scaling relation. These results permit one to conclude that humans reliably exploit the stable solutions inherent to the dynamics of the given task and do not overrule these dynamics by other control mechanisms. The dynamical scaling serves as an efficient principle for generating different movement realizations from only a few parameter changes and is discussed as a dynamical formalization of the principle of motor equivalence.  相似文献   
89.
Five rats and 4 pigeons responded for food delivered by several concurrent variable-interval schedules. The sum of the rates of reinforcement programmed for the two components varied from 15 to 480 reinforcers per hour in different conditions. Rates of responding usually changed within the experimental session in a similar manner for the two components of each concurrent schedule. The within-session changes were similar to previously reported changes during simple schedules that provided rates of reinforcement equal to the sum of all reinforcers obtained from the concurrent schedules. The number of changeovers also changed within sessions in a manner similar to the changes in instrumental responding. These results suggest that changeovers are governed by the same variables that govern instrumental responding. They also suggest that the within-session change in responding during each component of a concurrent schedule is determined by approximately the sum of the reinforcers obtained from both components when both components provide the same type of reinforcer.  相似文献   
90.
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