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   45504篇
  免费   1858篇
  国内免费   27篇
  47389篇
  2020年   443篇
  2019年   613篇
  2018年   823篇
  2017年   761篇
  2016年   884篇
  2015年   581篇
  2014年   763篇
  2013年   3536篇
  2012年   1374篇
  2011年   1424篇
  2010年   846篇
  2009年   940篇
  2008年   1212篇
  2007年   1239篇
  2006年   1139篇
  2005年   971篇
  2004年   985篇
  2003年   906篇
  2002年   923篇
  2001年   1427篇
  2000年   1480篇
  1999年   1064篇
  1998年   507篇
  1997年   437篇
  1995年   445篇
  1992年   870篇
  1991年   830篇
  1990年   818篇
  1989年   783篇
  1988年   771篇
  1987年   696篇
  1986年   700篇
  1985年   753篇
  1984年   600篇
  1983年   582篇
  1982年   458篇
  1979年   692篇
  1978年   520篇
  1977年   444篇
  1976年   456篇
  1975年   552篇
  1974年   658篇
  1973年   701篇
  1972年   599篇
  1971年   536篇
  1970年   470篇
  1969年   510篇
  1968年   651篇
  1967年   594篇
  1966年   553篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Six hens were exposed to several concurrent (second-order) variable-interval schedules in which the response requirements on the alternatives were varied. The response requirements were one key peck versus five key pecks, one key peck versus one door push, and five key pecks versus one door push. Response- and time-allocation ratios undermatched the obtained reinforcement ratios but were well described by the generalized matching law. Time and response bias estimates from two pairs of response requirements were used to predict bias in the third pairing. The predicted values were close to those obtained; this result supports the notion that both numerically and topographically different responses act as constant sources of bias within the generalized matching law. The differences between the response and time biases could be accounted for by the different times needed to complete each response requirement. The results also suggest that the door push is a useful operant for research with domestic hens.  相似文献   
992.
For years articles have decried the lack of empathy in physicians' relationships with patients. In addition to being empathetic, physicians are called upon to assume the posture of value neutrality, i.e., not imposing one's values when dealing with patients. Empathy is clearly an expression of deeply held values; even the language used to define it is value-laden. Physicians are consistently called upon to exhibit traits which are expressions of their underlying values. However, if proponents of value-neutrality are to be taken literally one must not impose any of one's values on one's patients. But then one wonders how empathy could ever be expressed; further, it is hard to imagine what a truly value neutral physician would be like. It is time we recognize that any relationship between two persons requires the expression of values from both parties. These values help shape that relationship and define its further history. Physicians are not excluded from this process just because they consider themselves professionals. Divulging personal values to patients is both more honest and more in keeping with the concepts of justice, beneficence, non maleficence, and autonomy than to feign value-neutrality. A presentation of some type statement of values is timely and would give patients an idea of where a physician stands on a myriad of issues. Rather than being value-neutral, value non-neutrality seems a more right and reasonable posture for physicians to assume.  相似文献   
993.
In this study, we explored differences in personality and daily life experiences of traumatized (n= 26) versus nontraumatized (n= 30) college students. Study participants completed a variety of personality measures as well as a 28–day experience sampling study assessing daily activities, emotions, and physical health. Although not differing on general demographics, traumatized individuals reported more trait anxiety and lower self–esteem than nontraumatized individuals. They scored higher on Neuroticism, were more introverted, and were less emotionally stable than nontraumatized participants. Traumatized individuals also reported more cognitive disturbances, emotional blunting, and interpersonal withdrawal. They did not report being more depressed, but did endorse cognitive styles associated with heightened risk for depression. Earlier age of trauma was associated with more pathological outcomes: lower self–esteem and psychological well–being, more anxiety, more pessimism, and emotional constriction of positive mood. We compare this symptom profile to that of posttraumatic stress disorder.  相似文献   
994.
995.
Few studies have examined the correlational and structural relationships between measures of hostility that may predict coronary heart disease. Using data from a population-based study (N= 2,682), we examined the factor structure among the five subscales from Siegel's (1986) Multi-dimensional Anger Inventory, the three subscales from Spielberger et al.'s (1985) anger expression scales, a Cook-Medley (Cook & Madley, 1954) hostility subscale that measures cynicism, and items measuring hostility from four scales that assess Type A behavior. Eight separate factors were identified: hostile anger expression, perceived control over the expression of one's anger, frequency of anger, ease of anger provocation, brooding, hostile outlook, cynicism, and sullenness. These results suggest that the structure of hostility measures is more complex than previous factor analyses have suggested. Our findings point to the dangers in assuming that a factor structure can be generalized beyond the data on which it is based to provide theoretical statements about psychological structure. The new scales appear to be valid because they correlate with demographic variables and indicators of social support in the expected directions.  相似文献   
996.
997.
998.
The control of the ground reaction force vector relative to the center of gravity (CoG) was examined while subjects performed a back-lifting task. Six male subjects (aged 24.0 +/- 2.5 years) repeatedly lifted a barbell. A biomechanical analysis that used a linked segment model revealed that the summed rotations of body segments during lifting yielded a specific rate of change of the angular momentum of the entire body. This equaled the external moment provided by Fsubg; relative to CoG. This implies that multisegment movements involve control of the angular momentum of the entire body through an appropriately directed Fsubg;. Thus, in dynamic tasks Fsubg; is pointed away from rather than lined up with the CoG, as is the case in static tasks.  相似文献   
999.
Investigated the effects of a 13-week preventive, psychoeducational intervention program to improve perceived social support. Fifty-one, low-perceived support, community residents were randomly assigned to an intervention or wait-list control condition. Intervention subjects received training in social skills and cognitive reframing regarding the self and social relations. The intervention led to increased perceived social support from family, but not from friends. As hypothesized by social cognition models, increases in perceived support appeared to be mediated by changes in self-esteem and frequency of self-reinforcement. Further, such changes in cognition about the self were larger than the changes observed for perceived support, suggesting that it may be easier to change cognition about the self than perceptions of support.  相似文献   
1000.
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