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   17590篇
  免费   1511篇
  国内免费   962篇
  2024年   31篇
  2023年   277篇
  2022年   237篇
  2021年   284篇
  2020年   595篇
  2019年   643篇
  2018年   608篇
  2017年   753篇
  2016年   726篇
  2015年   469篇
  2014年   622篇
  2013年   1985篇
  2012年   370篇
  2011年   447篇
  2010年   382篇
  2009年   583篇
  2008年   744篇
  2007年   803篇
  2006年   765篇
  2005年   658篇
  2004年   560篇
  2003年   461篇
  2002年   448篇
  2001年   278篇
  2000年   274篇
  1999年   229篇
  1998年   181篇
  1997年   153篇
  1996年   126篇
  1995年   110篇
  1994年   105篇
  1993年   84篇
  1992年   65篇
  1991年   47篇
  1990年   52篇
  1988年   42篇
  1987年   29篇
  1985年   368篇
  1984年   416篇
  1983年   344篇
  1982年   449篇
  1981年   441篇
  1980年   442篇
  1979年   394篇
  1978年   444篇
  1977年   349篇
  1976年   354篇
  1975年   272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 15 毫秒
331.
The contributions to this Special Issue illustrate research on several important types of environmental units, including psychiatric and substance abuse treatment programs, neighborhood block groups, and entire communities. They also exemplify alternative methodologies, such as assessing environments by relying on participants' appraisals, external observers' ratings, historical archives, and direct observation. I draw on these contributions and some of my own work to discuss four recurrent issues: (a) how to conceptualize environmental domains and dimensions; (b) how to understand environmental dynamics, that is, the interplay of environmental factors both within one setting and across settings; (c) how to comprehend the processes that link environmental factors to outcomes, especially with respect to the power and evanescence of environmental influence; and (d) how to use information about environments to monitor and improve them. Increased knowledge in these four areas is essential to help fulfill a major aim of community psychology: to understand social processes and improve intervention program outcomes.  相似文献   
332.
In this study it was determined whether (a) classification as opposed to absence of classification has an effect on the quality of clinical hypotheses (b) the DSM-III-R and the CBCL have a different effect on the quality of clinical hypotheses, and (c) the potential difference between the DSM-III-R and the CBCL is moderated by the different number of syndromes identified by these systems. To investigate these questions, an experiment was conducted in which 86 clinicians generated hypotheses for six cases. The clinicians were divided into a DSM-III-R, a CBCL, and a control group. Of the six cases, two were classified by both classification systems as one syndrome, two were classified as one syndrome by the DSM-III-R but as two syndromes by the CBCL, and two were classified as two syndromes by the DSM-III-R but as one syndrome by the CBCL. The quality of the hypotheses was determined by means of four dependent variables selected from an overview of qualitative criteria: explanatory value, redundancy, possibility of operationalization, and specificity. No differences between the CBCL and the control groups were found. The DSM group performed better than the control group regarding explanatory value and redundancy. The DSM-III-R group also scored better than the CBCL group regarding explanatory value, particularly when the number of identified syndromes was two for the CBCL and one for the DSM-III-R.  相似文献   
333.
A review of the literature resulted in 21 published studies that reported mean MMPI profile patterns for PTSD patients. Of these, six (29%) reported that the mean 8-2 profile pattern significantly differentiated PTSD patients from non-PTSD patients. The majority of studies found additional PTSD profile patterns reflecting nearly all of the MMPI clinical scales. The data indicate some common group profile patterns for inpatient veterans, prisoner's of war, and inpatient veteran substance abusers. The results also support the hypothesis that there is a continuum from inpatient to outpatient and veteran to civilian populations that corresponds with both symptom and stressor severity. It is concluded that although there is some typicality in similar populations, clinicians should expect heterogeneous MMPI profiles from PTSD patients representing a diversity of clinical symptoms and styles.  相似文献   
334.
A. F. Losev, one of the most important Russian philosophers and historians of ancient aesthetics and culture in the 20th century, develops in his ‘Dialectics of the Myth’ (Dialektika mifa), 1930, a personalistic ontology by using elements of neoplatonic philosophy and Orthodox Christian belief. According to Losev reality in all its different expressions and ontological strata must be understood as “mythical”, i.e. as “living mutual exchange of subject and object”. The subjective and personal aspect of reality is not grounded in man’s epistemic relation to it alone; reality in itself has to be characterized as personal and subjective. The main philosophical opponent is Descartes, the founder of “modern rationalism and mechanism”.
  相似文献   
335.
336.
Premise acceptability is conceptually connected to presumption. To say that a premise is acceptable just when there is a presumption in its favor is to give a first approximation to this connection. A number of popular principles of presumption suggest that whether there is a presumption for a premise, belief, or claim depends on the sources which vouch for it. Sources consist of internal belief-generating mechanisms and external testimony. Alvin Plantinga's notion of warrant lays down four conditions upon a source for the belief which it generates to be warranted. We argue that there is a presumption for a premise, belief, or claim if and only if there is a presumption of warrant for that premise,belief or claim. This amounts to the thesis that there is a presumption for a belief from a challenger's point of view if and only if there is a presumption from that person's point of view that her cognitive faculties which have generated the belief have been functioning properly, in an appropriate cognitive environment, in accord with a segment of her design plan aimed at the truth, and that these faculties are reliable. In light of our argument for this thesis, we may legitimately claim that one way to determine that there is a presumption for a belief is to determine that there is a presumption of warrant for that belief, and thus that in determining whether there is a presumption for a belief or premise, we may consider the source.  相似文献   
337.
本文运用个案研究方法 ,从人类理性的角度分析了企业在不同的生产经营条件下的目标设置方式 ,发现不确定性和目标难度对管理者的目标设置过程有很大的影响。在确定的 ,且任务较容易的情况下 ,目标设置是以一种与理性期望模型相一致的方式进行的 ,而在高度不确定的条件下 ,管理者则倾向于采用渐进适应的模式设置目标。对管理者的经营活动作进一步深入的分析发现 ,在高难度的任务目标情景中 ,决策者更多地从战略的层次 ,而不是从具体的层次上寻求实现目标的途径 ,从而提出了目标难度与实绩的“策略搜索层次”假设  相似文献   
338.
In teaching discriminations to persons with retardation, we often presume we will improve acquisition and generalization if we use multiple examples of boththe correct and incorrect stimuli. Two experiments were conducted to test this hypothesis. In the first experiment, 7 persons with moderate retardation learned to discriminate between functional words under two conditions. In one condition, Multiple Example of S- Only,1 example of the correct stimulus (S+) and 10 examples of the incorrect stimulus (S-) were used during acquisition. In the other condition, Multiple Examples of S+ and S-,10 examples of the S+ and 10 examples of the S- were used. Results showed that the condition which presented only a single example of S+ was superior 16 times and inferior 4 times during acquisition, generalization, and maintenance. A second experiment was conducted to (a) replicate the methodology and procedures in Experiment 1 with different participants, (b) determine whether the results were replicable, and (c) obtain efficiency data. Results replicated the findings of the first experiment. The condition which presented only a single example of S+ was superior on measures of (a) trials to criterion, (b) percent correct during acquisition, and (c) minutes to criterion. On measures of generalization, the two conditions were relatively equal. Thus, the condition which presented only a single example of the correct stimulus was more efficient and was just as effective in generalization as the condition which presented multiple examples of both the S+ and S-. These surprising results were discussed in terms of stimulus control, why students performed just as well during generalization when only one example of the S+ was used, why acquisition was also poorer for this condition, and how future studies might address these points.  相似文献   
339.
Should the nation provide expensive care and scarce organs to convicted felons? We distinguish between two fields of justice: Medical Justice and Societal Justice. Although there is general acceptance within the medical profession that physicians may distribute limited treatments based solely on potential medical benefits without regard to nonmedical factors, that does not mean that society cannot impose limits based on societal factors. If a society considers the convicted felon to be a full member, then that person would be entitled to at least a “decent minimum” level of care — which might include access to scarce life-saving organs. However, if criminals forfeit their entitlement to the same level of medical care afforded to all members of society, they still would be entitled to a kind of “rudimentary decent minimum” granted to all persons on simple humanitarian grounds. Almost certainly this entitlement would not include access to organ transplants.  相似文献   
340.
Individual and institutional conflict of interests in biomedical research have becomes matters of increasing concern in recent years. In the United States, the growth in relationships — sponsored research agreements, consultancies, memberships on boards, licensing agreements, and equity ownership — between for-profit corporations and research universities and their scientists has made the problem of conflicts, particularly financial conflicts, more acute. Conflicts can interfere with or compromise important principles and obligations of researchers and their institutions, e.g., adherence to accepted research norms, duty of care to patients, and open exchange of information. Disclosure is a key component of a successful conflict policy. Commitments which conflict with a faculty member's primary obligations to teaching, research, administrative responsibilities, or patient care also need attention. Institutional conflict of interests present different problems, some of which are discussed in an analysis of an actual problem posed by two proposed clinical trials. This paper is adapted from a lecture presented to a Symposium on Scientific Integrity, Warsaw, Poland, 23 November 1995. Daniel Steiner was Vice-President and General Counsel of Harvard University (1972–92) and in that capacity became familiar with conflict of interest issues. He is currently Counsel to the Boston law firm. Ropes and Gray, and is Adjunct Lecturer in Public Policy at the John F. Kennedy School of Government. Harvard University.  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