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:      
  示例: 沙坡头地区,人工植被区,变化  检索词用空格隔开表示必须包含全部检索词,用“,”隔开表示只需满足任一检索词即可!
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   22190篇
  免费   89篇
  国内免费   4篇
管理学   3205篇
民族学   122篇
人口学   1872篇
丛书文集   86篇
教育普及   1篇
理论方法论   1863篇
综合类   274篇
社会学   10548篇
统计学   4312篇
  2024年   130篇
  2023年   166篇
  2022年   112篇
  2021年   164篇
  2020年   423篇
  2019年   599篇
  2018年   685篇
  2017年   879篇
  2016年   706篇
  2015年   466篇
  2014年   654篇
  2013年   3740篇
  2012年   838篇
  2011年   767篇
  2010年   576篇
  2009年   481篇
  2008年   605篇
  2007年   562篇
  2006年   599篇
  2005年   480篇
  2004年   475篇
  2003年   398篇
  2002年   413篇
  2001年   510篇
  2000年   457篇
  1999年   421篇
  1998年   328篇
  1997年   278篇
  1996年   290篇
  1995年   299篇
  1994年   258篇
  1993年   262篇
  1992年   308篇
  1991年   304篇
  1990年   301篇
  1989年   260篇
  1988年   250篇
  1987年   213篇
  1986年   237篇
  1985年   254篇
  1984年   223篇
  1983年   199篇
  1982年   166篇
  1981年   134篇
  1980年   159篇
  1979年   173篇
  1978年   136篇
  1977年   117篇
  1975年   95篇
  1974年   96篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
951.
Community-based rehabilitative exercise programs might be an effective means to improve functional outcomes for hip-fracture patients. The purpose of this study was to evaluate the effectiveness of a community exercise program (CEP) for older adults recovering from hip fracture. Twenty-five older adults (mean age 80.0 +/- 6.0 years; 24 women; 71 +/- 23 days post-hip fracture) participated in this pilot study (17 exercise, 8 control). The CEP involved functional stepping and lower extremity-strengthening exercises. Control participants received only standard outpatient therapy. Measures of functional mobility, balance confidence, falls efficacy, lower extremity strength, and daily physical activity were evaluated at baseline and at 16 weeks. Improvements for self-reported physical activity, mobility, balance, and knee-extensor strength were observed for the CEP group. This study demonstrated that a CEP is beneficial for community-dwelling older adults post-hip fracture.  相似文献   
952.
To determine sex and race differences in muscle power per unit of muscle contraction, knee-extensor muscle power normalized for knee-extensor muscle volume was measured in 79 middle-aged and older adults (30 men and 49 women, age range 50-85 years). Results revealed that women displayed a 38% faster peak movement velocity than men and African Americans had a 14% lower peak movement velocity than Whites of a similar age when expressed per unit of involved muscle (p < .001). As expected, men exhibited greater knee-extensor strength and peak power per unit of muscle than women, but women had a faster knee- extension movement velocity per unit of muscle than men at the same relative strength level. Moreover, African Americans had greater knee-extensor muscle volume than Whites but exhibited lower knee-extensor strength and lower movement velocity per unit of muscle when tested at the same relative strength levels.  相似文献   
953.
Falls can impair health and reduce quality of life among older adults. Although many factors are related to falling, few analyses examine causal models of this behavior. In this study, factors associated with falling were explored simultaneously using structural-equation modeling. A variety of cognitive, physical-performance, and health measures were administered to 694 older adult drivers from the state of Maryland. The observed and latent variables of age, cognitive ability, physical functioning, health, and falling behavior were used to create a causal model. The model revealed that being older was associated with declines in cognition, and such cognitive declines predicted increased falling. Similarly, poorer health was related to poorer physical functioning, which, in turn, also predicted increased falling. This model indicates that in addition to existing fall-prevention interventions aimed at improving physical functioning, interventions to improve cognition and health might also be effective. It is speculated that fear of falling, which often results in reduced mobility among older adults, might account for the lack of a direct relationship between age and falling. This hypothesis should be examined in further research.  相似文献   
954.
Trauma survivors may experience harm from participating in research on sensitive topics. The current study assessed reactions of sexual assault survivors with and without symptoms of post-traumatic stress disorder (PTSD) immediately following an experimental thought suppression task and at a 2- to 4-week follow-up period, by asking open-ended questions regarding thoughts about the experiment, feelings following the experiment, and willingness to participate in similar experiments. At both time periods, most participants reported neutral/positive thoughts (e.g., "interesting") and feelings (e.g., "fine, good") and indicated that they would participate in a similar study. Findings suggest that the majority of sexual assault survivors were not harmed in the short- or long-term by participation in a thought suppression paradigm in which the target of suppression/expression was their own trauma.  相似文献   
955.
This study examined vicarious trauma effects in male and female clinicians who treat sexual abuse survivors (n = 111) and sexual offenders (n = 272). The national survey was conducted using a random sample of clinical members of two professional organizations. Analyses tested the relationships between demographic variables, maltreatment history, client population served, and cognitions about trust of and intimacy with others, using the Trauma Stress Institute Belief Scale (TSIBS-R-L, Pearlman 2003), the Childhood Trauma Questionnaire (CTQ, Bernstein & Fink, 1998), and author-generated questions. Respondents reported high rates of multiple forms of childhood maltreatment; however there was no relationship between history of child sexual abuse and vicarious trauma effects. Scores for self-reported disruption in cognitions about intimacy with others exceeded norms for mental health professionals. Sequential regression analyses were used to examine theoretically-derived variables. Implications for practice and research are detailed.  相似文献   
956.
957.
Mutations in the DJ-1 gene are associated with rare forms of autosomal recessive early-onset Parkinson's disease (PD). Although the precise physiological function of DJ-1 remains obscure, accumulating evidence suggests that DJ-1 may normally function as a redox-sensitive molecular chaperone that can protect against the deleterious effects of oxidative stress, particularly in mitochondria. Recent studies in the fruit fly, Drosophila melanogaster, have shed further light on the biological role of DJ-1. DJ-1-deficient Drosophila models exhibit distinct phenotypes but collectively highlight a prominent neuroprotective role for DJ-1 against oxidative insult. However, Drosophila lacking DJ-1 do not consistently produce a useful PD-like phenotype (that is, they generally fail to exhibit degeneration of neurons that contain the neurotransmitter dopamine), which may reflect putative compensatory neuroprotective mechanisms. DJ-1-deficient fly models further highlight the utility of Drosophila as an important tool for elucidating protein function and for modeling neurodegenerative disease.  相似文献   
958.
959.
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