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   60754篇
  免费   2406篇
  国内免费   23篇
  2020年   580篇
  2019年   651篇
  2018年   917篇
  2017年   945篇
  2016年   1037篇
  2015年   771篇
  2014年   899篇
  2013年   4338篇
  2012年   1684篇
  2011年   1696篇
  2010年   1118篇
  2009年   1042篇
  2008年   1560篇
  2007年   1478篇
  2006年   1323篇
  2005年   1210篇
  2004年   1187篇
  2003年   1115篇
  2002年   1142篇
  2001年   1782篇
  2000年   1741篇
  1999年   1306篇
  1998年   633篇
  1997年   592篇
  1996年   577篇
  1992年   1230篇
  1991年   1174篇
  1990年   1171篇
  1989年   1047篇
  1988年   1048篇
  1987年   1009篇
  1986年   1066篇
  1985年   1126篇
  1984年   895篇
  1983年   804篇
  1981年   584篇
  1979年   1007篇
  1978年   710篇
  1977年   654篇
  1976年   665篇
  1975年   864篇
  1974年   1035篇
  1973年   1092篇
  1972年   891篇
  1971年   876篇
  1970年   825篇
  1969年   845篇
  1968年   1101篇
  1967年   979篇
  1966年   932篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Most knowledge of parent-offspring relations in mammals is derived from studies of mother-infant interactions. Male parental care has been less well studied. We explored maternal and paternal behavior of the California mouse, Peromyscus californicus. Six pairs of parents and their young were videotaped continuously for 12 hours/day, on alternate days from Days 1 to 31 postpartum. Males exhibit all parental activities and to the same extent as displayed by mothers, except lactation. Male parental behavior begins on the day of birth. Mothers and fathers spend substantial and equivalent amounts of time in the nest and in physical contact with pups throughout lactation. Males devote more time than females to licking pups, although females engage in more pup anogenital licking. Mothers nurse for at least 4 weeks, and fathers and mothers both build nests and carry young. The biparental care system of Peromyscus californicus affords an opportunity to develop a broader, more complete view of parent-offspring relations.  相似文献   
952.
We developed the Sheltered Care Environment Scale (SCES) to provide researchers and practitioners with a practical means of assessing the social climate in congregate residential settings for the elderly. The SCES, a 63-item yes/no questionnaire that can be completed by residents and staff members of a facility, taps their perceptions of seven dimensions of the social environment. These dimensions concern the quality of relationships, the personal growth orientation present in the facility, and maintenance and change of the social system. The SCES discriminates among settings, has moderate to high internal consistency and split-half reliability, and is sensitive to environmental change against a backdrop of relative stability over time. The SCES reflects actual, agreed-on qualities of a setting and is relatively unaffected by characteristics of the respondent. Normative data are available from a national sample of 244 facilities representing the variety of residential settings available to the elderly.  相似文献   
953.
This study is an extension of previous observational work on the social ecology of dependence and independence in the institutionalized elderly. Observations of everyday, naturally occurring interactions between elderly residents of two different long-term institutions and their social partners were extended such that, aside from the identification of type of behavior, the dyadic form and continuity of each behavior was specified. The following were among the major results: (a) Previously found interaction patterns between elderly residents and their social partners, replicated in both a nursing home and a home for the chronically ill, supported the notion of discrepant social ecologies for dependent versus independent behaviors of residents: (b) specification of each behavioral act as to its dyadic form underscored the fact that the interactions were controlled largely by social partners and not by the elderly residents; (c) coding continuity or discontinuity of behavior suggested that independent behaviors were maintained by chaining; and (d) elderly residents in the home for the chronically ill evinced, as expected, more dependence-related behaviors.  相似文献   
954.
Twenty elderly subjects (70-90 years old) and 20 young control subjects (18-24 years old) underwent three kinds of olfactory testing: absolute thresholds to three odorants (d-limonene, iso-amyl butyrate, benzaldehyde), magnitude matching of these odorants to salt tastes, and odor identification of 30 common substances. For all three odorants elderly subjects' mean threshold significantly exceeded that of the young by about ninefold for d-limonene, about threefold for benzaldehyde, and about twofold for iso-amyl butyrate. These threshold differences predict approximate concentration differences necessary to arouse the same estimated odor strength above the threshold for the elderly and the young. Young subjects also scored better than the elderly in odor identification, even when subjects were given four alternatives from which to select the correct label. Unimpaired olfactory functioning is uncommon in the elderly; correlational tests show that as a group the young have better olfactory ability and show more interindividual uniformity.  相似文献   
955.
In three experiments, 469 subjects watched a short videotape of a bank robbery and later estimated the duration of the tape. Subjects invariably overestimated the durations. Accuracy of time estimation was unrelated to amount of free recall (Experiment 1) or accuracy of memory (Experiment 2). Females overestimated to a greater degree than males (Experiments 2 and 3). A more stressful version of the event produced greater overestimates than a less stressful version (Experiment 3). The relationship between induced arousal and time estimation appears to be different for men and women.  相似文献   
956.
Elderly subjects were 41% less accurate than young subjects in localizing a point in the frontal plane. The decline could be ascribed neither to an age difference in image formation or skill acquisition nor to a difference in motivational level or trace retention. Evidently the "ambient" or "transient" visual system is compromised at an elementary level. Reasons why this deficit may not be compounded at more complex levels of spatial processing are suggested.  相似文献   
957.
We compared the effect of two approaches, family counseling and support groups, for relieving the stress and burden experienced by care givers of dementia patients. Both treatments are designed to implement features of a stress-management model that have been identified in prior research with this population: providing information about the patient's disease and its effects on behavior, teaching behavioral problem solving for managing difficult behavior, and identifying potential support for care givers. Subjects were primary care givers of dementia patients living in the community; they included husbands, wives, daughters, and other relatives. Although subjects in the treatment groups made significant gains over time, they did not differ from wait-list subjects who showed similar improvements. One-year follow-up interviews indicated that gains made during the treatment period were maintained.  相似文献   
958.
959.
The authors demonstrate the complexities and processes involved in constructing a screening test for posttraumatic stress disorder (PTSD). Discussion includes item development, field testing, and preliminary results.  相似文献   
960.
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