全文获取类型
收费全文 | 39071篇 |
免费 | 1474篇 |
国内免费 | 13篇 |
出版年
2019年 | 417篇 |
2018年 | 569篇 |
2017年 | 548篇 |
2016年 | 593篇 |
2015年 | 413篇 |
2014年 | 573篇 |
2013年 | 2919篇 |
2012年 | 978篇 |
2011年 | 1075篇 |
2010年 | 696篇 |
2009年 | 682篇 |
2008年 | 997篇 |
2007年 | 958篇 |
2006年 | 919篇 |
2005年 | 771篇 |
2004年 | 800篇 |
2003年 | 767篇 |
2002年 | 774篇 |
2001年 | 1029篇 |
2000年 | 1106篇 |
1999年 | 807篇 |
1998年 | 442篇 |
1997年 | 419篇 |
1996年 | 424篇 |
1995年 | 407篇 |
1992年 | 736篇 |
1991年 | 693篇 |
1990年 | 706篇 |
1989年 | 659篇 |
1988年 | 666篇 |
1987年 | 610篇 |
1986年 | 666篇 |
1985年 | 651篇 |
1984年 | 553篇 |
1983年 | 522篇 |
1981年 | 404篇 |
1979年 | 625篇 |
1978年 | 512篇 |
1977年 | 416篇 |
1976年 | 428篇 |
1975年 | 532篇 |
1974年 | 636篇 |
1973年 | 689篇 |
1972年 | 539篇 |
1971年 | 550篇 |
1970年 | 474篇 |
1969年 | 533篇 |
1968年 | 648篇 |
1967年 | 601篇 |
1966年 | 591篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
161.
Knowledge and beliefs regarding the consequences of cigarette smoking and their relationships to smoking status in a biracial sample 总被引:3,自引:0,他引:3
R C Klesges G Somes R W Pascale L M Klesges M Murphy K Brown E Williams 《Health psychology》1988,7(5):387-401
The purpose of this investigation was to evaluate carefully smoking-related knowledge and beliefs and their relationships to smoking status in a large, heterogeneous sample of smokers and nonsmokers in two settings: (a) a large, biracial southern city and (b) a small midwestern community. Participants were 611 (198 male, 413 female) adult respondents to a random-dialing telephone survey in Fargo, North Dakota (n = 200), and Memphis, Tennessee (n = 411). Each participant was given the Smoking Attitudes Survey, which assesses generalized health beliefs as well as health-related problems associated with smoking. Participants' knowledge of smoking-associated diseases (e.g., lung cancer) and of diseases not associated with smoking (e.g., kidney stones) was assessed. Stepwise regression analysis of composite knowledge scores revealed four independent predictors of the health consequences of smoking: education, race, smoking status, and income. Smokers, compared to nonsmokers, reported less knowledge related to the health consequences of smoking, were more likely to be male, were less concerned with the health consequences of smoking, and were more concerned about the health consequences of cholesterol. The best predictor of smokers who had never attempted cessation was their greater concern over weight control when compared to smokers with a history of smoking cessation attempts. The results are discussed in terms of smoking prevention and intervention efforts. 相似文献
162.
163.
Rats were allowed to forage in a simulated natural environment made up of eight food sources (patches) each containing a fixed number of pellets. Two of the eight contained an extra supply of peanuts. The peanut patches were signaled by an olfactory/visual cue located at the bottom of the ladder leading to the patch. In successive phases the number of sessions per day, height of the patches, and availability of peanuts were manipulated. Subjects showed evidence of discrimination learning under these conditions, although the degree of discriminatory behavior varied as a function of environmental manipulations. Assessment of behavior within foraging sessions showed that subjects systematically changed their patterns of utilization of patches across time. Sampling or exploration, as well as food reinforcement, seem implicated in these results. 相似文献
164.
The present experiments were designed to teach pigeons to discriminate two locations represented by color photographs. Two sets of photographs were taken at two distinctive locations on a university campus. These sets represented several standpoints at each location. For the true-discrimination group, pictures from the two locations were differentially associated with reward; for the pseudodiscrimination group, half of the views from each location were arbitrarily but consistently associated with reward. The former group acquired the discrimination much more rapidly. These birds also showed good transfer to new views from the standpoints used in training and to a new standpoint at each location not used in training. In a second experiment, another group of pigeons could terminate any training trial by pecking an “advance” key. Three of 4 subjects used this option to reduce the duration of trials in which pictures from the negative location were presented. These data suggest that pigeons can integrate views shown in pictures into a “concept” of a location. The method used here may be the experimental analogue of a common, natural process by which animals learn to identify locations. 相似文献
165.
166.
167.
Body-frame size is an important factor in determining an optimal body weight for a given height. Previous studies have indicated that many individuals incorrectly estimate their body-frame size, and, as a result, incorrectly assess their ideal weight. The present study investigated the accuracy of estimation of body-frame size as a function of sex and actual frame size. The subjects were 66 men and 52 women participating in a community adult fitness program. Data indicated that medium-framed individuals were the most accurate in their estimations of body-frame size. Also, women were twice as likely to be accurate as were men. These results are interpreted to mean that most people assume they are medium-framed and that there is a sex difference in the way body-frame size is estimated. 相似文献
168.
Cutoff scores are used in a variety of settings to help managers make personnel decisions. Although cutoff scores are used widely, information about their derivation and appropriate use is scattered in the legal, psychometric, and professional literatures. The purpose of this paper is to analyze critically and to integrate these diverse literatures, to summarize what is known and what is unknown about the use and misuse of cutoff scores. Alternative methods are examined in relation to legal precedents set by the courts, to psychometric principles, and to the various sets of professional guidelines. Directions for future research are suggested, and we conclude with a set of recommendations regarding acceptable professional practice in this area. 相似文献
169.
170.
This research investigated the buffering role of social support in the relationship of work load to both tension-anxiety and coping for police radio dispatchers ( N = 60). Each dispatcher was observed throughout an entire 8-hour work shift by a trained observer. Objective load consisted of the hourly rate of incoming telephone calls, police radio transmissions, and face-to-face or written communications from superiors, co-workers, and others. At the end of each shift, measures were taken of dispatchers' perceived load, felt tension-anxiety, and coping actions. Hierarchical regression revealed that support from superiors moderated the effects of both objective and perceived loads; no main effects of support were found. Statistically significant interactions confirmed the hypothesized buffering role of support: under high perceived load, dispatchers with high social support engaged in more coping actions and felt less tension-anxiety than did low-support dispatchers. No differences were found when perceived load was low. Support also buffered effects of objective load on tension-anxiety but not on coping. 相似文献