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   53124篇
  免费   1996篇
  国内免费   24篇
  55144篇
  2019年   603篇
  2018年   842篇
  2017年   916篇
  2016年   895篇
  2015年   656篇
  2014年   778篇
  2013年   3982篇
  2012年   1380篇
  2011年   1519篇
  2010年   1026篇
  2009年   977篇
  2008年   1403篇
  2007年   1299篇
  2006年   1229篇
  2005年   1054篇
  2004年   991篇
  2003年   1044篇
  2002年   1024篇
  2001年   1718篇
  2000年   1670篇
  1999年   1256篇
  1998年   599篇
  1997年   541篇
  1996年   523篇
  1995年   510篇
  1992年   1097篇
  1991年   1058篇
  1990年   1004篇
  1989年   946篇
  1988年   937篇
  1987年   913篇
  1986年   920篇
  1985年   966篇
  1984年   783篇
  1983年   658篇
  1981年   532篇
  1979年   818篇
  1978年   624篇
  1977年   581篇
  1976年   563篇
  1975年   713篇
  1974年   804篇
  1973年   891篇
  1972年   686篇
  1971年   648篇
  1970年   607篇
  1969年   647篇
  1968年   765篇
  1967年   691篇
  1966年   748篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
953.
954.
955.
956.
957.
We examined the effect of reducing the interval between a patient's call for an appointment and the appointment itself. In Experiment 1, patients calling a family planning unit of a public health department were assigned appointments within either 1 or 3 weeks of their call. Data on patient “shows” and “no-shows” were recorded weekly for 6 weeks. Show rates for those in the 1-week appointment group were significantly higher than those in the 3-week group. In Experiment 2, patients were assigned to appointment dates either the next operating clinic day (next-day group) or 2 weeks from the call date (2-week group). Show rates for those in the next-day group were significantly better than show rates for patients in the 2-week group. Clinic productivity, time spent with patients, and consumer satisfaction were also assessed. Implications for appointment scheduling are discussed.  相似文献   
958.
This research had two aims. The first was to test three explanations of performance on N-term series tasks by young children: the labeling model of B.DeBoysson-Bardies and K. O'Regan (1973), Nature (London), 246, 531–534, the sequential-contiguity model of L. Breslow (1981, Psychological Bulletin, 89, 325–351), and the ordered array or image model of C. A. Riley and T. Trabasso (1974, Journal of Experimental Child Psychology, 17, 187–202). In the first experiment, 5-year-old children were taught additional premises which would interfere with labeling and sequential-contiguity processes, but not with forming an ordered array. Reasoning performance was essentially comparable to previous results with the paradigm, thus supporting the ordered array model. The second aim was to reexamine children's ability to learn sets of premises which can be assembled into an ordered array, since there was reason to believe that previous studies had created false positives. In the second experiment, 3- to 7-year-old children were taught either overlapping (a > b, b > c, …) or nonoverlapping (a > b, c > d, …) premises. Overlapping premises can be integrated into an ordered array (a, b, c, d, e), but nonoverlapping premises cannot. However, the overlapping condition proved more difficult, and the success rate for preschoolers (312- to 412-year-olds) was of zero order. This raises doubts about their ability to learn a set of premises of the kind required for transitive inference. These doubts were strengthened by the third experiment which showed that when premises were not presented in serial order, preschool (312- to 412-year-old) children could not learn the premises of an N-term series task.  相似文献   
959.
In two longitudinal studies, infants were trained at 12 and 18 months to find an object hidden in one of two identical wells in a Plexiglas box. On the test trial, normal access was blocked and infants were either guided by their mother or allowed to move on their own to another opening on the opposite side. In Experiment 1 significantly more correct responding occurred after active movement than after passive at 12 months, with correct responding related to high visual tracking. In contrast, at 18 months correct search without tracking predominated among both movement conditions. A difference between the conditions in the position of the mother on the test trial was ruled out as a contributor to performance on the basis of data from Experiment 2. When opaque sides were inserted to prevent tracking in Experiment 3, active movement no longer facilitated correct search at 12 months, thus indicating that the tracking and not the active movement per se was the critical factor.  相似文献   
960.
Politicians sometimes shift the stances that they take on issues. An experiment investigated the effect of such a shift upon observers' perceptions of and feelings about an ostensible candidate for public office. The target issue (private ownership of handguns) was chosen as being relatively emotional for some subjects and unemotional for others. Subjects were also selected (independently) as being either pro or con on the issue. The position taken by the stimulus person (who, in contrast to previous research, was identified as a candidate for office) was portrayed as initially being either similar or dissimilar to that of the subject. An assessment of the candidate's position 6 months later indicated either no change or a reversal of the initial position. Subjects' evaluations of the candidate on a variety of dimensions yielded a consistent pattern. The combination of initial agreement and final agreement was viewed more favorably than any other combination. Taken together, the data suggest two conclusions. First, there was no support in this context for the notion that a shift from disagreement to agreement would be especially valued (i.e., there was no “gain” effect). Second, in the realm of politics, people value consistent agreement with their own position—but they do not reward consistency per se.  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