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   4045篇
  免费   220篇
  国内免费   10篇
  2023年   49篇
  2022年   47篇
  2021年   54篇
  2020年   100篇
  2019年   119篇
  2018年   149篇
  2017年   147篇
  2016年   174篇
  2015年   93篇
  2014年   118篇
  2013年   502篇
  2012年   194篇
  2011年   218篇
  2010年   136篇
  2009年   121篇
  2008年   149篇
  2007年   179篇
  2006年   155篇
  2005年   133篇
  2004年   120篇
  2003年   116篇
  2002年   125篇
  2001年   78篇
  2000年   61篇
  1999年   49篇
  1998年   38篇
  1997年   43篇
  1996年   29篇
  1995年   39篇
  1994年   48篇
  1993年   34篇
  1992年   41篇
  1991年   26篇
  1990年   28篇
  1989年   31篇
  1988年   33篇
  1987年   32篇
  1986年   33篇
  1985年   40篇
  1984年   25篇
  1983年   25篇
  1982年   28篇
  1981年   24篇
  1980年   25篇
  1979年   26篇
  1978年   35篇
  1977年   20篇
  1975年   15篇
  1974年   23篇
  1973年   19篇
排序方式: 共有4275条查询结果,搜索用时 15 毫秒
51.
52.
The plastic barrel suit provides complete protection of chronically implanted fistulas and electrical connectors. The lost time, expense, and the frustrations of having these devices damaged was avoided.  相似文献   
53.
54.
Bulk of liquid held in the mouth may be judged on its subjective volume. Over the range I ml-31 ml, scaling by the constant method and by ratio estimation yielded a Weber fraction which was not constant and decreased with stimulus magnitudes and a psychophysical power function with an exponent of 0.96. A “negative threshold” effect is reported.  相似文献   
55.
56.
Wayne Lee 《Psychometrika》1966,31(3):397-412
A method of design symbolization (DS) is given for a class of designs in which all factors are related by complete crossing or by nesting. Characterization of acceptable DS's, and logical relational properties are given. It is shown how the design model can be obtained from the DS.The preparation of this article was supported by NIH Grant GM-11128, and by grants to the Institute of Human Learning by NSF and NIH.  相似文献   
57.
58.
The 3RT Test consists of a simple, a choice, and a conditional reaction time (RT) task. The three tasks involve comparable visual stimuli and require identical manual responses, but they differ in the complexity of cognitive processing required. The nonverbal stimuli convey commonly known meanings. Responses can be made either on the keyboard or on response keys connected to the computer’s serial port. The computer’s internal timer/counter is used for millisecond timing. The test administration program allows flexible setting of the test conditions. The data analysis program provides summary data not only for each RT task as a whole, but also for separate trial types within each task. Summary statistics include measures of variation and central value that are not affected by extreme scores. In addition to laboratory studies with normal adults, the 3RT Test is suitable for life-span developmental studies, cross-cultural comparisons, and other uses in various clinical settings.  相似文献   
59.
Tolbutamide has previously been shown to amplify the pressor effects of “exogenous” catecholamines in conscious dogs, possibly due to sensitization of the α1-adrenoreceptor-mediated vasoconstriction. The objective of this study was to examine if tolbutamide also amplifies the pressor effects of “endogenous” catecholamines released during psychological stress (classical Pavlovian aversive conditioning). Experiments were conducted in β-adrenoreceptor-blocked (propranolol, 1 mg/kg, i.v.) conscious dogs (n=4) trained in classical aversive conditioning. Conditioning was accomplished by following a tone (CS+) with a 1/2 second shock; another tone (CS-) was not followed by any shock and served as control. With saline pretreatment, aversive conditioning (i.e., CS+) increased mean arterial pressure (MAP) only by approximately 4.7% when compared to CS-, whereas with tolbutamide (45 mg/kg, i.v.) pretreatment, the increase in MAP induced by CS+ beyond what was induced by the CS- (approximately 6.2%) was significantly (p<0.05) larger than that with saline pretreatment. In isolated canine femoral arterial segments (n=4), the vasoconstrictor effect of phenylephrine (an α1-agonist) at 5×10?6M (which was the EC50 value) was amplified by 2×10?2M of tolbutamide from 54.0±2.0% to 66.9±2.1%. In conclusion, tolbutamide amplifies the pressor effects of “endogenous” catecholamines in conscious dogs, possibly by sensitization of the α1-adrenoreceptor-mediated vasoconstriction. This mechanism of action is novel and has not been reported with other agents.  相似文献   
60.
The influence of interparental verbal and physical aggression, children's coping styles, and relevant demographic factors on children's adjustment was examined in a group of 52 families who were disputing custody and/or access arrangements after separation. It was hypothesized that parental conflict and specific children's coping strategies (i.e., cognitive redefinition and social support seeking) would be important predictors of children's adjustment. Consistent with previous research, aggressive styles of resolving conflict between parents were related to more frequent and severe behavior problems and diminished competence among children. Conversely, greater flexibility in coping and greater use of cognitive coping strategies among children were related to decreased behavioral disturbance. The unique and combined influence of these variables is discussed.This research was supported in part through a grant from the LaMarsh Research Programme on Violence and Conflict Resolution, York University, Toronto, Ontario. The author acknowledges the help of Cathy Melville and Susan Dickens in the data analyses. In addition, the author thanks the staff and families at the Toronto and London, Ontario, Family Court clinics who participated in this project.  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