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   24720篇
  免费   1088篇
  国内免费   13篇
  25821篇
  2020年   329篇
  2019年   327篇
  2018年   527篇
  2017年   482篇
  2016年   512篇
  2015年   353篇
  2014年   474篇
  2013年   1987篇
  2012年   813篇
  2011年   869篇
  2010年   458篇
  2009年   554篇
  2008年   742篇
  2007年   723篇
  2006年   691篇
  2005年   593篇
  2004年   556篇
  2003年   558篇
  2002年   491篇
  2001年   831篇
  2000年   829篇
  1999年   626篇
  1998年   275篇
  1997年   247篇
  1996年   223篇
  1995年   219篇
  1993年   229篇
  1992年   501篇
  1991年   441篇
  1990年   502篇
  1989年   416篇
  1988年   399篇
  1987年   374篇
  1986年   399篇
  1985年   452篇
  1984年   360篇
  1983年   295篇
  1982年   236篇
  1979年   334篇
  1978年   262篇
  1977年   213篇
  1975年   302篇
  1974年   348篇
  1973年   356篇
  1972年   280篇
  1971年   241篇
  1969年   228篇
  1968年   291篇
  1967年   252篇
  1966年   272篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
We report an eye movement experiment investigating the influence of the focus operator only on syntactic processing of "long" relative clause sentences. Paterson, Liversedge, and Underwood (1999) found that readers were garden pathed by "short" reduced relative clause sentences containing the focus operator only . They argued that due to thematic differences between "short" and "long" relative clause sentences, garden path effect might not occur when "long" reduced relative clause sentences are read. Eye-tracking data show that garden path effects found during initial processing of the disambiguating verb of "long" reduced sentences without only were absent or delayed in the case of counterparts with only . We discuss our results in terms of current theories of sentence processing.  相似文献   
12.
13.
In two experiments, hungry rats were given instrumental lever-press training for an appetitive reinforcer and, in addition, were exposed to another type of food which was not contingent on lever pressing. In the first experiment, exposure to each type of food was on separate days, whereas in the second experiment rats were exposed to each type of food in strict alternation within each session. Subsequently, a food aversion was conditioned to the reinforcer for the experimental group and to the non-contingent food for the control group. In both experiments, animals with an aversion to the reinforcer responded less in an extinction test than animals with an aversion to the non-contingent food. Subsequent reacquisition tests confirmed that the aversion to the non-contingent food in the control group was of comparable strength with that to the reinforcer in the experimental group. The results were discussed in terms of whether the reinforcer is encoded in the associative structure set up by exposure to an instrumental contingency.  相似文献   
14.
15.
16.
Although perceived health risk plays a prominent role in theories of health behavior, its empirical role in risk taking is less clear. In Study 1 (N = 129), 2 measures of drivers' risk-taking behavior were found to be unrelated to self-estimates of accident concern but to be related to self-ratings of driving skill and the perceived thrill of driving. In Study 2 (N = 405), out of a wide range of potential influences, accident concern had the weakest relationship with risk taking. The authors concluded that although health risk is a key feature in many theories of health behavior and a central focus for researchers and policy makers, it may not be such a prominent factor for those actually taking the risk.  相似文献   
17.
This study evaluated cardiovascular responses (CVR) to an active speech task with blatantly discriminatory (BRC) versus neutral (NRC) stimuli and an anger recall task in a sample of Black men (N = 73; age 18 to 47). Diastolic blood pressure scores were higher for NRC versus BRC stimuli during anger recall (p = .05). Moreover, persons in the NRC group who perceived high levels of racism (vs. no racism or BRC group) during active speech showed larger increases in blood pressure across postspeech rest, anger recall, and subsequent rest (p = .03). The notable elevation in CVR in response to an ambiguous event extends current models of racism suggesting that subtle racism is a psychosocial stressor that erodes health through chronically elevated CVR.  相似文献   
18.
Do the conditions under which promises are made determine whether they ought to be kept? Philosophers have placed a number of conditions on promising which, they hold, must be met in order to make promise-keeping obligatory. In so doing, they have distinguished valid promises from invalid promises and justified promises from promises that are not justified. Considering such conditions, one by one, we argue that they are mistaken. In the first place, the conditions they lay down are not necessary for either valid or justified promise-making. In the second place, promises need not meet such conditions in order to create moral obligations. In general, such analyses of promising fail because they suffer from a confusion between promise-making and promise-keeping. Philosophers have wrongly supposed that obligations to keep promises are dependent upon, or derivable from, the quality of the promises themselves, at the time they are made, instead of focusing on conditions that must be satisfied at the time when promises are supposed to be kept. It is not the quality of a promise that determines an obligation to keep it but the rightness or wrongness of performing the promised act.  相似文献   
19.
OBJECTIVE: This report reviews the evidence that informs the role of health and mental health care providers in addressing youth smoking cessation. DESIGN: Qualitative literature review. RESULTS: Physicians do not consistently screen adolescents for tobacco use and fail to provide recommended cessation advice. Challenges to addressing smoking cessation include the need for procedures to ensure confidentiality and the existence of competing demands to provide other services. Few published studies have specifically addressed the effectiveness of clinical interventions. Interventions that require return visits or follow-up phone contacts are technically difficult to implement in this population. Successful interventions may require resources not available in nonresearch settings. Most studies have used brief clinical intervention as a control condition, making it impossible to evaluate its effectiveness. CONCLUSION: There is little evidence that supports current clinical smoking cessation guidelines for adolescents. More research is needed to develop inexpensive, efficient clinical interventions that can provide youths access to smoking cessation help. Future challenges include reorganizing clinical systems to offer greater counseling by support staff or in electronic formats and to provide effective booster messages and follow-up care in a population that is difficult to track.  相似文献   
20.
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