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   26305篇
  免费   269篇
  国内免费   129篇
教育   18323篇
科学研究   2692篇
各国文化   167篇
体育   2696篇
综合类   25篇
文化理论   241篇
信息传播   2559篇
  2021年   180篇
  2020年   295篇
  2019年   436篇
  2018年   1220篇
  2017年   1242篇
  2016年   989篇
  2015年   406篇
  2014年   499篇
  2013年   4026篇
  2012年   553篇
  2011年   823篇
  2010年   653篇
  2009年   550篇
  2008年   673篇
  2007年   672篇
  2006年   478篇
  2005年   420篇
  2004年   673篇
  2003年   576篇
  2002年   561篇
  2001年   687篇
  2000年   502篇
  1999年   402篇
  1998年   233篇
  1997年   253篇
  1996年   257篇
  1995年   275篇
  1994年   229篇
  1993年   229篇
  1992年   368篇
  1991年   310篇
  1990年   325篇
  1989年   363篇
  1988年   325篇
  1987年   310篇
  1986年   303篇
  1985年   331篇
  1984年   290篇
  1983年   330篇
  1982年   256篇
  1981年   238篇
  1980年   238篇
  1979年   349篇
  1978年   256篇
  1977年   226篇
  1976年   231篇
  1975年   183篇
  1974年   185篇
  1973年   186篇
  1971年   164篇
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
941.
Blocked practice engenders more trial-to-trial response stability, which is thought to be crucial for developing the generalized motor program (GMP) but not parameter learning (Lai, Shea, Wulf, & Wright, 2000). It was hypothesized that reducing the difficulty of the GMP might permit additional cognitive resources to be allocated to learning the parameter requirements. However, GMP theory maintains the independence of the memories governing the GMP and parameters. This notion suggests that manipulating the difficulty of the GMP should have no effect on the blocked practice participant's ability to successfully specify the appropriate parameters. Participants learned a simple or complex relative timing pattern under either blocked or random practice conditions. Smaller GMP errors were exhibited for the simple relative timing patterns, but this was not associated with improvements in parameter specification following blocked practice. A clear advantage for parameter specification was evident in transfer following random practice. Taken together, these data support the theoretical separation of the GMP and parameter processes.  相似文献   
942.
The most important points in grand slam singles tennis   总被引:1,自引:0,他引:1  
A computerized data management system was used to enter details of points played in 252 tennis matches from the men's and women's singles events of all four Grand Slam tournaments over a 2-year period. A supplementary data analysis system was developed to determine the proportion of points won by each player on serve at each game score from love all to deuce as well as the proportion of games the player went on to win from each score. Analysis of the 43 matches in which both players served at each score from love all to deuce revealed that the proportion of points won by the server was not significantly influenced by score, F(15, 495) = 0.8, p > .05. A further analysis of the 175 matches consisting of at least 100 points revealed that the proportion of points won by the superior player was not significantly influenced by gender, F(1, 165) = 0.1, p > .05, or surface, F(3, 165) = 0.1, p > .05. However, the proportion of points won when serving was significantly greater in men's singles than women's singles, F(1, 165) = 69.7, p < .001, R2 = .30. Surface also had a significant influence on the proportion of points won when serving, F(3, 165) = 8.1, p < .001, R2 = .13, with a significantly greater proportion of points won when serving by both winning and losing players at Wimbledon than at the Australian and French Opens, p < .05. This suggests that gender and surface should be accounted for when determining the importance of points in Grand Slam tennis.  相似文献   
943.
944.
This chapter traces the way in which Nellie Kleinsmidt, known as the grandmother of karate in Africa, has negotiated discriminatory practices and overcome race and gender-related struggles, including the struggle to free the female body, in pursuit of empowerment. It explores her expectations and the constraints and frustrations she experienced, as well as the many contributions she has made to women's karate in South Africa. Nellie Kleinsmidt's karate career, which began in 1965, coincided with the early developments of South African karate. As a woman of colour her life and karate career were significantly shaped by apartheid legislation. It divided the country into areas of occupancy and residency according to race and was designed to prevent contact between the people of the government defined race groups. Black karate-kas were prohibited by law from practising karate in white designated areas. Lack of facilities and qualified instructors in areas allocated to Kleinsmidt's race group meant that she received very little formal karate instruction between 1966 and 1973. Soon after, she met Johan Roux, a white male. He was to become her chief karate instructor and life-long companion. They defied the apartheid legislation and in 1978 set up home together. They organized defiance campaigns, resisting the pressures from government to close their dojo because of its non-racial policies. Freeing her body at the broader political level involved the abolition of the race categories and all other apartheid legislation which impacted on her life choices and experiences. Initially this struggle and that of freeing her body occurred simultaneously. In her ongoing struggle against gender discrimination in the sport, it was in karate that Nellie Kleinsmidt could strive for the personal empowerment she sought. She could however not translate this into freedom in South African society itself. The impact of apartheid legislation together with the imposition of a sports moratorium by the South African Council on Sports (SACOS), hindered the growth of Nellie Kleinsmidt's karate career, yet she managed to obtain her sixth Dan Black Belt in 1998. This was a remarkable achievement given the constraints she had to overcome. In karate, Kleinsmidt was often viewed as a female first. The problem of female access is exacerbated by the overwhelming number of male instructors perpetuating the notion that the martial arts are inherently male sports. Accessing the various levels of karate has involved claiming physical and symbolic space on the dojo floor as well as involvement in the decision-making arenas of karate. In 1992 with the unification of karate in South Africa, Sensei Nellie began to extend her involvement with the refereeing arena and jointly established a Women's Karate Forum in her province. She has subsequently become a South African national referee and has earned the status of continental judge with the Union of African Karate Federation (UFAK). Nellie Kleinsmidt is the first and only woman of colour to have been appointed to the Referee's Board of South Africa and the only woman of colour in Africa to have obtained a sixth Dan Black belt.  相似文献   
945.
In the early 1970s physicians engaged in fierce debates over the most appropriate method of evaluating the efficacy of coronary artery bypass grafting (CABG). With millions of patients and billions of dollars at stake, CABG sparked fierce controversy. Skeptics demanded that randomized controlled trials (RCTs) be performed, while enthusiasts argued that they already had visual proof of CABG's efficacy. When RCTs appeared, they did not settle the controversy. Participants simply reasserted their preconceptions, defending a trial's strengths or exploiting its flaws. The debate centered on standards of knowledge for the evaluation of therapeutic efficacy. Specifically, cardiologists and cardiac surgeons struggled to assess the relevance of different measures of therapeutic success: physiological or clinical, visual or statistical. Many factors contributed to participants' decisions, including disciplinary affiliation, traditions of research, personal experience with angiography, and assessments of the history of cardiac therapeutics. Physicians had to decide whether angiography provided a meaningful representation of the disease and its treatment or whether demonstrations of therapeutic success could come only from long-term statistical evaluation of mortality data.  相似文献   
946.
OBJECTIVE: To study the circulation of monographs during the first three years of shelf life at an academic health sciences library. METHOD: A record was kept of monographs added to the circulating collection from mid-1994 to mid-1995. After three years, each monograph was located and the number of times it circulated during the first, second, and third year of shelf life determined by counting checkout stamps on the circulation slip. RESULTS: Of the 1,958 monographs studied, 1,674 had complete data for the first three years of shelf life. Of those 1,674 titles, 81.48% circulated at least once. A total of 7,659 circulations were recorded; 38.69% occurred in the first year of shelf life, 32.37% in the second year, and 28.95% in the third year. The data did not fit the well-known 80/20 rule. Instead, approximately 38% of monographs accounted for 80% of circulation. A small percentage, 2.21%, of monographs accounted for a substantial percentage of circulation, 21.84%. CONCLUSIONS: A large percentage of the monographs circulated and use did not decline sharply with age within the first three years of shelf life, indicating a high demand for monographs at this academic health sciences library. These results, combined with the findings of earlier studies, suggested two possibilities. First, academic health sciences libraries might exhibit use of a higher percentage of monograph acquisitions than other types of libraries; or, second, a low monograph-to-user ratio might result in a higher percentage of monographs being used. Perhaps both factors contributed to the results found in this study. Further investigation would be needed to determine the extent to which library type and monograph-to-user ratio influenced monograph use.  相似文献   
947.
948.
949.
The aim of this study was to distinguish between the roles of uncontrollability and failure on learned helplessness in a perceptual-motor task. Forty-eight junior high school students were randomly assigned in a 2 x 2 (Controllability: Contingent vs. Yoked Noncontingent Feedback x Type of Outcome: Success vs. Failure) factorial design to complete a gun-shooting task on a moving target using a computer screen. Twelve other participants (control group) simply read a passage. After filling out causal attribution and self-efficacy expectations questionnaires, all participants carried out another gun-shooting task (test task). Results showed that contingency led to higher performances than noncontingency. Success conditions elicited higher self-efficacy expectations than failure conditions. Failure entailed less persistence than success did for participants who had been assigned to the contingency condition. Internalization of failure was negatively correlated with persistence. Comparisons with the control group showed that expectations and performance deficits of learned helplessness were provoked by failure in noncontingent situations; persistence deficits were due to failure in contingent situations. These results reveal that both uncontrollability and failure can be responsible for different forms of learned helplessness.  相似文献   
950.
From novice to no know-how: a longitudinal study of implicit motor learning   总被引:1,自引:1,他引:0  
The aim of this study was to ascertain whether the performances of implicit and explicit learners would converge over an extended period of learning. Participants practised a complex motor skill--golf putting--for 3000 trials, either with a concurrent secondary, tone-counting task (implicit learning) or without such a task (explicit learning). The cognitive demands of the secondary task were predicted to prevent the accumulation of verbalizable rules about the motor task. The implicit group reported significantly fewer rules than the explicit group on subsequent verbal protocols. The performance of the implicit group remained below that of the explicit group throughout the learning phase. However, no significant differences were found between groups during a delayed retention test. Additionally, for the participants in the explicit group only, a Reinvestment Scale score correlated positively with the number of rules accrued and negatively with overall putting performance during the learning phase. We use the results to argue against the excessive use of verbal instruction during skill acquisition, which might be unnecessary and ultimately might hamper performance under stressful conditions.  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