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   31722篇
  免费   1285篇
  国内免费   19篇
  33026篇
  2020年   380篇
  2019年   534篇
  2018年   696篇
  2017年   639篇
  2016年   700篇
  2015年   493篇
  2014年   650篇
  2013年   3008篇
  2012年   1127篇
  2011年   1193篇
  2010年   733篇
  2009年   761篇
  2008年   1040篇
  2007年   1061篇
  2006年   1049篇
  2005年   891篇
  2004年   882篇
  2003年   860篇
  2002年   843篇
  2001年   799篇
  2000年   830篇
  1999年   621篇
  1998年   411篇
  1997年   391篇
  1996年   377篇
  1995年   337篇
  1994年   312篇
  1993年   300篇
  1992年   449篇
  1991年   476篇
  1990年   462篇
  1989年   425篇
  1988年   392篇
  1987年   378篇
  1986年   380篇
  1985年   435篇
  1984年   366篇
  1983年   357篇
  1982年   293篇
  1981年   301篇
  1980年   284篇
  1979年   372篇
  1978年   338篇
  1975年   322篇
  1974年   357篇
  1973年   364篇
  1972年   284篇
  1971年   270篇
  1968年   292篇
  1967年   280篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
941.
A two-part system for digital measurement of such diverse response parameters as latency, pulse width, amplitude, and events per unit time is described. The mainframe consists of counters with light-emitting diode (LED) numeric readouts and a quartz crystal controlled internal time base. It also contains all power supply requirements for both the mainframe electronics and the second part of the system, the plug-ins. Each plug-in is designed to use the main unit counters, timers, readouts, and power supplies to measure the desired parameter. Thus, each numeric readout channel of the mainframe may be used to measure various parameters simply by changing the plug-in attached to it. The unit has proved to be very useful in reducing experimenter error in measuring response parameters in classical nictitating membrane conditioning.  相似文献   
942.
The present experiments examined the role of imagery ability in recall of either the terminal location or the distance of a preselected horizontal linear movement following changes in the recall starting position. Subjects were selected on the basis of their scores on a shortened version of the Betts Questionnaire upon Mental Imagery (Betts Q.M.I., Sheehan 1967). Both high and low imagers were assigned to one of four groups, HIL, LIL, HID, LID, the last letter indicating the movement cue (terminal location or distance moved) to be recalled. Recall of the appropriate movement cue from one of four new recall starting positions occurred after either a 5-sec or 30-sec unfilled retention interval. Analysis of constant error indicated all groups were unable to recall the specified movement cue independent of the other source of information, even when subjects were given explicit instructions to utilise an imagery strategy. The data corroborate our earlier findings that memory for self paced movements is based on an interaction of location and distance cues derived from the criterion movement.  相似文献   
943.
944.
Holland's Self-Directed Search was administered to 247 male and 252 female high school students, aged 16 to 18 years, attending state schools in New Zealand. Principal factor analysis was used in an attempt to identify six orthogonal factors analogous to Holland's six personality types. The Social and Enterprising scales could not be split into two factors in either sample, and the Investigative and Realistic scales defined a single factor for the female students. Computed distances between pairs of the six personality types in five dimensional factorial space were compared with the relative ordering of the distances expected from Holland's hexagonal model. The positions of the types in space corresponded more closely with the model for the males than they did for the females. The results, in conjunction with those of similar studies in Israel and the United States, imply that the correspondence between some summary codes on the SDS and existing occupational classifications based on Holland's types may be less than perfect, particularly for females. Also, care should be taken when using codes on the SDS to calculate Holland's indices of “consistency,” especially for females.  相似文献   
945.
The attention demands of initiating and controlling discrete movements were examined as a function of their movement time (MT) and average movement velocity. Experiment 1 showed that the attention required to execute a movement decreased as MT decreased, although Experiment 2 through independently manipulating MT and movement velocity, revealed that movement velocity is the key determiner of attention demands rather than MT. The attention demands of preparing a high velocity movement are greater than during its execution with the reverse being the case for relatively slow velocity movements. The results are compatible with the view that it is the initiation of error corrections that are attention demanding (Keele 1973).  相似文献   
946.
Previous research has demonstrated the relationship of work stress to indices of job strain, as well as underscoring the importance of moderating variables. In the present study of a mining organization it was hypothesized that personnel associated with actual mining operations would demonstrate stress-strain relationships different from those associated with administrative and staff work. Measures of stress and strain were obtained from management staff of blue-collar and white-collar groups to assess the moderating influence of collar color. Results strongly support collar color as a moderator variable. In particular, the two groups differ significantly with respect to how role conflict, job security, quantitative work load, variation in work load, and utilization of skills impact various strains. The effect of job function on stress and strain and possible practical implications of these results are discussed.  相似文献   
947.
In two experiments, posthypnotic amnesia was suggested for a word list memorized during hypnosis. After an initial test of amnesia the subjects gave word associations (Experiment 1) or category instances (Experiment 2) to stimuli intended to elicit the critical (word list) items covered by the amnesia. The extent of initial amnesia observed was strongly associated with measured hypnotic susceptibility. Even among the most hypnotizable subjects, however, the dense amnesia did not prevent the critical items from being elicited by the semantic memory tasks, nor did it modulate the priming which these associations received by virtue of the prior learning experience. Moreover, production of the critical items did not, in general, remind the amnesic subjects of those items which they had previously learned, but could not now remember. Full memory was restored after the amnesia suggestion was canceled by a prearranged cue. Posthypnotic amnesia appears to represent a temporary dissociation of episodic features from memory traces, so that the subject has difficulty in reconstructing the context in which the target events occurred.  相似文献   
948.
Typically, citizens lack relevant information concerning possible consequences of proposed environmental projects. Despite federal requirements for citizen participation in decisions about proposed roadway projects, no systematic procedures exist for educating citizens as to the possible consequences of such projects. The effects of a consequence analysis procedure on community residents' verbal statements about the favorability of a proposed roadway project were assessed. The consequence analysis procedure involved asking residents to rate the desirability and magnitude of each of 48 possible consequences of the proposed roadway project. Following the intervention, overall ratings of favorability of the project changed for nine of ten residents. Community residents' ratings of the quality of participants' justifications of their position on the roadway issue provided evidence of generalization to this collateral behavior.  相似文献   
949.
The comprehension of sentences with “because” or “if” was investigated in children aged 2;9–11;11. Imitation, comprehension (choosing one of two picture sequences to go with a sentence), recognition (judging sentences with connective or structure differences as heard before or not), and synonymy (judging equivalence of meaning in sentences with different connectives or structures) tasks were administered, along with logical ordering, reversibility, and classification tasks. Above-chance responding in the comprehension task occurred by age 8, and in recognition and synonymy by age 10. Cognitive performance predicted 28.4% of the variance in the linguistic scores and cognitive success was concurrent with or preceded linguistic success. Comprehension of “because” and “if” appears to develop gradually, and is related to the development of certain operative rules.  相似文献   
950.
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