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   41937篇
  免费   1587篇
  国内免费   22篇
  2020年   434篇
  2019年   423篇
  2018年   707篇
  2017年   686篇
  2016年   712篇
  2015年   461篇
  2014年   634篇
  2013年   3070篇
  2012年   1169篇
  2011年   1278篇
  2010年   730篇
  2009年   781篇
  2008年   1096篇
  2007年   1086篇
  2006年   1008篇
  2005年   892篇
  2004年   862篇
  2003年   819篇
  2002年   822篇
  2001年   1430篇
  2000年   1421篇
  1999年   1073篇
  1998年   475篇
  1997年   410篇
  1992年   879篇
  1991年   783篇
  1990年   865篇
  1989年   771篇
  1988年   731篇
  1987年   713篇
  1986年   750篇
  1985年   819篇
  1984年   625篇
  1983年   556篇
  1982年   432篇
  1981年   385篇
  1979年   671篇
  1978年   508篇
  1977年   435篇
  1976年   410篇
  1975年   613篇
  1974年   691篇
  1973年   674篇
  1972年   570篇
  1971年   512篇
  1970年   443篇
  1969年   526篇
  1968年   619篇
  1967年   544篇
  1966年   566篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
881.
Forty normotensive subjects participated on a voluntary basis in a study designed to compare the effect of suggestions on blood pressure (BP). Two experimental groups received suggestions presumed to be specific in lowering or raising BP after simple relaxation (relaxation group) or hypnotic induction (hypnotic group). A control group was used to record the BP changes over time. The time variable was significant for both systolic (SBP) and diastolic blood pressure (DBP). Induction procedures (hypnosis or relaxation) resulted in significant decreases in DBP in both experimental groups. In the control group there was a significant decrease in SBP. A specific suggestion to increase the BP resulted only in DBP increase in the hypnotic group. This group also gave an increase of both SBP and DBP over the entire experiment, whereas the relaxation group resulted in a significant decrease in SBP. There was no significant group variable, indicating no differences between the groups. Further research is needed to enable firm conclusions of the effect of suggestions on BP.  相似文献   
882.
Attention, Perception, & Psychophysics - Speech perception abilities are modified by linguistic experience to maximize sensitivity to acoustic contrasts that are important for one’s...  相似文献   
883.
Although current theories of memory emphasize the fact that learning is an active process, there is little consensus on the role of active learning. This paper attempts to provide a more precise characterization of active learning in the acquisition of computer skills. The analysis of verbal protocols suggests that active learning varies on at least two dimensions: schema orientation and learning strategy. Schema orientation refers to the type of information the learner is acquiring and varies from relational information to procedural information. Learning strategy describes how the information is acquired. Some people prefer to be internally driven and form their own plans for learning. Others are externally driven and allow the instructional materials to guide their learning. These differences need to be taken into account in describing learning and in designing instructional materials.  相似文献   
884.
Prior surgical implantation of a venous catheter sensitized rats to coldimmobilization stress. Three of six catheterized females succumbed during the stress. The remaining rats fell into two groups in terms of their core temperature at the end of the stress period: Male uncatheterized rats had higher temperatures than rats in the other three groups. No relation was found between catheter patency and magnitude of hypothermia. Degree of gastric disease paralleled the core temperature findings in that the male uncatheterized rats had significantly fewer gastric erosions than the rats in the other three groups. Additionally, a robust effect of gender was found with uncatheterized females showing more hypothermia and more gastric disease than uncatheterized males. A subsequent experiment was conducted to evaluate whether anesthesia or wearing the protective spring was responsible in part for the sensitization seen. Here, the gender difference was less although females consistently averaged lower core temperatures after stress than did males. Despite similar core temperatures after stress, females that were prepared with the protective spring apparatus developed more gastric disease than female controls or similarly treated males. Thus, the additional sensitization exhibited by females in the first experiment may relate to the fact that both catheterization and the taping procedure were sensitizers while only catheterization was a sensitizer for males.  相似文献   
885.
Recent studies have begun to test certain fundamental assumptions underlying popular models of feature perception. This research is continued here. It was discovered that every basic assumption that was open to test in the present study was disconfirmed. However, several new characteristics of line and curve feature perception were discovered: (1) Feature perception sensitivity was inversely related to the number of features present in a stimulus pattern, and the decision criteria for reporting a feature decreased with the number of features contained in a pattern; (2) the decrements in sensitivity reported in (1) were greater for features lying inside a pattern than for those on the exterior; and (3) feature perception sensitivity actually improved if another feature was known to be correctly perceived during the same trial. Likewise, feature sensitivity decreased if another feature was missed on any trial. At the present time, a system that first extracts global and then local (more detailed) featural information provides a basis that qualitatively accounts for our findings and is also compatible with several other studies in the literature.  相似文献   
886.
R Warren  G Good  E Velten 《Adolescence》1984,19(75):643-648
This paper provides some initial normative and validity data on the Social Avoidance and Distress (SAD) and the Fear of Negative Evaluation (FNE) scales for junior high school students. Findings indicated: the level of social-evaluative anxiety does not significantly vary during the junior high school years or between sexes, junior high school students report similar levels of FNE to college students but less SAD, a significant positive correlation between treatment subjects' SAD scores and peer sociometric ratings of social-evaluative anxiety, and subjects treated for social anxiety reported significantly less SAD and FNE at follow-up assessment. Recommendations for future research and clinical use of the SAD and FNE are offered.  相似文献   
887.
The present study examined some previously reported relationships between drug use by adolescents and perceived attitudes and behaviors of their parents. An anonymous questionnaire was administered to the student body of an inner-city secondary school for difficult students. Relationships between parental use of drugs and adolescent use of the same drugs were moderate and roughly equivalent across drugs. However, parental use of marijuana was strongly related to the adolescent's use of other, harder drugs such as opiates, cocaine, amphetamines, and barbiturates. This finding is explained within the framework of Kandel's postulated stages of drug initiation. It points to a need for further study of parental influences, which may be increasingly problematic as more individuals who have grown up in our marijuana-accepting society become parents of adolescents.  相似文献   
888.
D Klein  P Belcastro  R Gold 《Adolescence》1984,19(76):805-815
Several inherent limitations to secondary school sex education program evaluations are: limited generalizability, lack of longitudinal research, and no clear consensus of program outcomes. With a Bureau of Health Education, Center for Disease Control study as the criterion for program outcomes, a study was undertaken to examine the immediate and long-term impact of sex education upon program participants. Two of the 20 schools in the CDC study identified as having exemplary sex education programs provided access to their students and alumni. Inventories which measured perceived achievement of 33 sex education outcomes were piloted for reliability and validity. Each inventory examined participant changes in knowledge, understanding of self, values, interaction skills, self-esteem, and fear of sex-related activities. Students were surveyed in school; alumni were surveyed through the mail. Response rates ranged from 30 to 100 percent for students and alumni at both schools. Overall there was no statistically significant difference between the perceptions of students and alumni as to achievement of investigated outcomes. Alumni responses at one school did, however, indicate some potentially weak areas of their school's program with respect to values and interaction skills outcomes. It appears that program impact may decrease with time. Thus, isolating and addressing the factors involved may be necessary. This would assist program planners and instructors to strengthen curricula and program activities in order to enhance the overall impact of sex education. The present study supports the notion that positive gains are achieved as a result of each school's sex education program, and these gains remained over time.  相似文献   
889.
This study examined changes in cognitive-dissonance-related variables during the professional training period. Differences in levels and change in satisfaction with career choice, importance of career, certainty of career decision, self-occupational perceptions, general attitude toward career, time since career decision, and past experience were observed when students who left a collegiate professional training program before program completion were compared with those who remained in the program. Data supports the validity of D. Hershenson and R. Roth's (1966, Journal of Counseling Psychology, 13, 368–370) and V. Harren's (1979, Journal of Vocational Behavior, 14, 119–133) theoretical models of vocational decision and the Assessment of Career Decision Making scale.  相似文献   
890.
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