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   15427篇
  免费   317篇
  国内免费   193篇
  2012年   1529篇
  2011年   1691篇
  2010年   381篇
  2009年   193篇
  2008年   1323篇
  2007年   1251篇
  2006年   1181篇
  2005年   960篇
  2004年   866篇
  2003年   783篇
  2002年   742篇
  2001年   454篇
  2000年   548篇
  1999年   240篇
  1998年   85篇
  1997年   43篇
  1996年   63篇
  1995年   37篇
  1994年   86篇
  1993年   100篇
  1992年   106篇
  1991年   112篇
  1990年   104篇
  1989年   106篇
  1988年   127篇
  1987年   133篇
  1986年   102篇
  1985年   130篇
  1984年   118篇
  1983年   141篇
  1982年   102篇
  1981年   98篇
  1980年   83篇
  1979年   89篇
  1978年   84篇
  1966年   48篇
  1965年   133篇
  1964年   104篇
  1963年   126篇
  1962年   55篇
  1958年   151篇
  1957年   130篇
  1956年   143篇
  1955年   84篇
  1954年   81篇
  1953年   75篇
  1952年   71篇
  1951年   72篇
  1950年   44篇
  1949年   51篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
261.
Pigeons responded on two keys in each component of a multiple concurrent schedule. In one series of conditions the distribution of reinforcers between keys within one component was varied so as to produce changes in ratios of reinforcer totals for key locations when summed across components. In a second series, reinforcer allocation between components was varied so as to produce changes in ratios of reinforcer totals for components, summed across key locations. In each condition, resistance to change was assessed by presenting response-independent reinforcers during intercomponent blackouts and (for the first series) by extinction of responding on both keys in both components. Resistance to change for response totals within a component was always greater for the component with the larger total reinforcer rate. However, resistance to change for response totals at a key location was not a positive function of total reinforcement for pecking that key; indeed, relative resistance to extinction for the two locations showed a weak negative relation to ratios of reinforcer totals for key location. These results confirm the determination of resistance to change by stimulus—reinforcer contingencies.  相似文献   
262.
A review of the literature was conducted to better understand the (potential) role of mental health professionals in physician-assisted suicide. Numerous studies indicate that depression is one of the most commonly encountered psychiatric illnesses in primary care settings. Yet, depression consistently goes undetected and undiagnosed by nonpsychiatrically trained primary care physicians. Noting the well-studied link between depression and suicide, it is necessary to question giving sole responsibility of assisting patients in making end-of-life treatment decisions to these physicians. Unfortunately, the use of mental health consultation by these physicians is not a common occurrence. Greater involvement of mental health professionals in this emerging and debated area is advocated. Beyond describing mental health professionals' role in the assessment of patient competency or decision making capacity, other areas of potential involvement are described. A discussion of ethical principles relevant to this area follows, along with comments on the training necessary to adequately serve patient needs.  相似文献   
263.
对人的尊严的挑战——试论P.辛格的优先权——实利主义   总被引:2,自引:0,他引:2  
一个社会对其成员重视和承认的程度,首先表现为这个社会如何对待其成员中的弱者和受歧视的人。而在每个社会遭受歧视的人中,无疑也包括那些由于先天或后天的缘故患有精神上或肉体上的疾病而需要特别照顾的人。1989年以来,首先是这一社会群体的代言人,对他们的遭遇提出了强烈的抗议。而他们的抗议,又引发了德国舆论界对澳大利亚哲学家彼得·辛格的关注。特别是辛格关于可以对残疾人(既包括先天不足的婴儿,也包括老年人)施行强制性安乐死的论述,点燃了论战的烽火,更激起了一部分人的强烈抗议。残疾人的代盲人指出,辛格的“实用伦理学”不仅是对“残疾人”,而且从根本上讲是对人的错误认识。  相似文献   
264.
 取120名12岁儿童作被试.(a)调查外向性格、神经过敏症及场独立性之间的关系.(b)调查外向性格和场依存性对两个认知作业(推理和回忆散文)的影响.(c)研究人格特点和言语——表象学习方式之间的关系.  相似文献   
265.
A theoretical analysis of the structure and dynamics of human motor functioning is presented from the perspective of a general theory of individuality. Within multifactor-systems theory, the structural units of the six systems of integrative personality (i.e., sensory, motor, cognitive, affect, style, and value) are hierarchical factor structures. Integrative functioning, both within and among systems, is described via the principles of general systems and information-processing theory. Our theoretical synthesis of the structure and dynamics of human motor functioning involves conceptualizing the hierarchy of motor factors as: (a) the basic dimensions of individual differences in the motor domain, (b) classes of decomposable motor programs that specify the spatio-temporal organization of behavior, and (c) decomposable classes of processing components entailed by motor programs. Some of the implications for understanding the role of affect in motor functioning and some research suggestions were presented.  相似文献   
266.
267.
Key pecking of four birds was reinforced with food according to a two-component multiple variable-interval 1-minute variable-interval 4-minute schedule. In addition, key pecking was punished by a brief shock according to a variable-interval 30-second schedule during both components of the multiple schedule. The intensity of the shock was varied. For all birds, punishment had a stronger suppressive effect on the responding maintained by the leaner food schedule, and the ratio of responding during the two components of the multiple schedule became closer to the ratio of reinforcement as shock intensity was increased, as the relative law of effect predicts. At the higher shock intensity, there was some evidence that the ratio of responses overmatched the ratio of reinforcements.  相似文献   
268.
Six pigeons were trained on multiple and concurrent schedules. The reinforcement rates were varied systematically (a) when lever pressing was required in one component and key pecking in the successive component; (b) when lever pressing was required in both multiple components; (c) when key pecking was required in both multiple components; and (d) when key pecking was required on one schedule and lever pressing was required on the concurrently-available schedule. Only the absolute level of responding was changed by different response requirements. Analyzed by the generalized matching law, performance under different response requirements resulted in a bias toward key pecking, and the measured response bias was the same in multiple and concurrent schedule arrangements. The bias in time measures obtained from concurrent schedule performance was reliably smaller than the obtained response biases. The sensitivity to reinforcement-rate changes was ordered: concurrent key-lever; multiple key-key; multiple lever-key; and, the least sensitive, multiple lever-lever. The results confirm that requirements of different topographical responses can be handled by the generalized matching law mainly in the bias parameter, but problems for this type of analysis may be caused by the changing sensitivity to reinforcement in multiple schedule performance as response requirements are changed.  相似文献   
269.
270.
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