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   2770484篇
  免费   200250篇
  国内免费   4579篇
耳鼻咽喉   40543篇
儿科学   88858篇
妇产科学   79219篇
基础医学   397837篇
口腔科学   80034篇
临床医学   242482篇
内科学   528181篇
皮肤病学   59095篇
神经病学   216516篇
特种医学   108835篇
外国民族医学   720篇
外科学   426670篇
综合类   63362篇
现状与发展   4篇
一般理论   767篇
预防医学   206046篇
眼科学   64949篇
药学   214555篇
  8篇
中国医学   5917篇
肿瘤学   150715篇
  2018年   26406篇
  2016年   22973篇
  2015年   26332篇
  2014年   36597篇
  2013年   55363篇
  2012年   75318篇
  2011年   80173篇
  2010年   47269篇
  2009年   44343篇
  2008年   76055篇
  2007年   82171篇
  2006年   82872篇
  2005年   80749篇
  2004年   77907篇
  2003年   75269篇
  2002年   73343篇
  2001年   127559篇
  2000年   131031篇
  1999年   110841篇
  1998年   30995篇
  1997年   27700篇
  1996年   27638篇
  1995年   26137篇
  1994年   24454篇
  1993年   22890篇
  1992年   88868篇
  1991年   86822篇
  1990年   85414篇
  1989年   82888篇
  1988年   76601篇
  1987年   75170篇
  1986年   71473篇
  1985年   68217篇
  1984年   50980篇
  1983年   43955篇
  1982年   25953篇
  1981年   23189篇
  1979年   48587篇
  1978年   34003篇
  1977年   29499篇
  1976年   26968篇
  1975年   29904篇
  1974年   35783篇
  1973年   34548篇
  1972年   32950篇
  1971年   30728篇
  1970年   28765篇
  1969年   27918篇
  1968年   25562篇
  1967年   22926篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
As millions of people turn to social media for health information, better understanding the factors that guide health-related judgments and perceptions in this context is imperative. We report on two Web experiments (n > 400 total) examining the power of society’s widespread weight bias and related stereotypes to influence nutrition judgments in social media spaces. In Experiment 1, meals were judged as lower in nutritional quality when the person who recommended them (the source) was depicted as obese rather than of normal weight, an effect mediated by stereotypic beliefs about the source as a generally unhealthy person. Experiment 2 replicated this effect, which—notably—remained significant when controlling for objective nutritional information (calories and fat content). Results highlight spillover effects of weight bias that extend beyond person perception to color impressions of objects (here, food) that are associated with stigmatized attributes. Implications for everyday nutrition judgments and public health are considered.  相似文献   
82.
83.
84.
85.
86.
The catechol-O-methyltransferase (COMT) enzyme is a major determinant of prefrontal dopamine levels. The Val158Met polymorphism affects COMT enzymatic activity and has been associated with variation in executive function and affective processing. This study investigated the effect of COMT genotype on the flexible modulation of the balance between processing self-generated and processing stimulus-oriented information, in the presence or absence of affective distractors. Analyses included 124 healthy adult participants, who were also assessed on standard working memory (WM) tasks. Relative to Val carriers, Met homozygotes made fewer errors when selecting and manipulating self-generated thoughts. This effect was partly accounted for by an association between COMT genotype and visuospatial WM performance. We also observed a complex interaction between the influence of affective distractors, COMT genotype and sex on task accuracy: male, but not female, participants showed a sensitivity to the affective distractors that was dependent on COMT genotype. This was not accounted for by WM performance. This study provides novel evidence of the role of dopaminergic genetic variation on the ability to select and manipulate self-generated thoughts. The results also suggest sexually dimorphic effects of COMT genotype on the influence of affective distractors on executive function.  相似文献   
87.
Preimplantation genetic diagnosis (PGD) was originally developed to diagnose embryo-related genetic abnormalities for couples who present a high risk of a specific inherited disorder. Because this technology involves embryo selection, the medical, bioethical, and legal implications of the technique have been debated, particularly when it is used to select features that are not related to serious diseases. Although several initiatives have attempted to achieve regulatory harmonization, the diversity of healthcare services available and the presence of cultural differences have hampered attempts to achieve this goal. Thus, in different countries, the provision of PGD and regulatory frameworks reflect the perceptions of scientific groups, legislators, and society regarding this technology. In Brazil, several texts have been analyzed by the National Congress to regulate the use of assisted reproduction technologies. Legislative debates, however, are not conclusive, and limited information has been published on how PGD is specifically regulated. The country requires the development of new regulatory standards to ensure adequate access to this technology and to guarantee its safe practice. This study examined official documents published on PGD regulation in Brazil and demonstrated how little direct oversight of PGD currently exists. It provides relevant information to encourage reflection on a particular regulation model in a Brazilian context, and should serve as part of the basis to enable further reform of the clinical practice of PGD in the country.  相似文献   
88.
89.
90.
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