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   3618篇
  免费   283篇
  国内免费   19篇
耳鼻咽喉   14篇
儿科学   68篇
妇产科学   127篇
基础医学   607篇
口腔科学   35篇
临床医学   349篇
内科学   677篇
皮肤病学   78篇
神经病学   493篇
特种医学   126篇
外科学   338篇
综合类   28篇
一般理论   5篇
预防医学   330篇
眼科学   54篇
药学   229篇
中国医学   5篇
肿瘤学   357篇
  2024年   1篇
  2023年   27篇
  2022年   68篇
  2021年   129篇
  2020年   92篇
  2019年   89篇
  2018年   107篇
  2017年   103篇
  2016年   140篇
  2015年   148篇
  2014年   190篇
  2013年   223篇
  2012年   350篇
  2011年   375篇
  2010年   172篇
  2009年   164篇
  2008年   264篇
  2007年   241篇
  2006年   231篇
  2005年   229篇
  2004年   180篇
  2003年   173篇
  2002年   137篇
  2001年   14篇
  2000年   7篇
  1999年   16篇
  1998年   15篇
  1997年   12篇
  1996年   6篇
  1995年   1篇
  1993年   4篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1985年   1篇
  1980年   2篇
  1979年   2篇
排序方式: 共有3920条查询结果,搜索用时 984 毫秒
61.
Delayed childbearing is currently a major challenge in reproductive medicine as increased age has an important impact on successful conception, both in natural and in assisted reproduction. There is a lack of knowledge about the impact of age on fertility, even in highly educated populations. A number of initiatives have been taken to increase fertility awareness. Health care providers have been encouraged to talk with patients about their reproductive life plan (RLP) for almost a decade based on recommendations from the Centres for Disease Control and Prevention. This concept has been explored successfully in Swedish contraception counselling. A growing number of online interventions aim to raise fertility awareness. These websites or interactive tools provide relevant information for individuals and couples as they consider whether they want children, when they should have them, and how many they may wish to have. These interventions are important, because research depicts that knowledge helps people in their decision-making process. With new fertility preservations such as egg freezing now available, additional education is needed to be sure that women and couples are well informed about the cost and low success rates of this intervention.  相似文献   
62.
63.
64.
Background Different reasons influence the current low birth-rate and the postponement of the birth of the first child throughout Europe. The aim of this study was to explore how highly educated women and men in Sweden reflect on fertility and postponed parenthood.Methods We interviewed women (n = 22) and men (n = 18) who had started their professional careers and still had no children. Data were analysed with qualitative content analysis.Results Fertility was perceived as an unconsidered capacity, sometimes unpredictable, and different for women and men, but nevertheless taken for granted. The participants were of the opinion that fertility could be restored by assisted reproductive technologies or replaced by alternatives to a biological child. Postponed parenthood was described as an adaptation to societal changes and current discourses about parenthood as well as a consequence of a contemporary lifestyle with many competing priorities.Conclusion Highly educated young women and men in contemporary Sweden have competing priorities when planning and setting goals for their lives, and having children is one of them. They describe fertility as an imperceptible and retrievable capacity and postponed parenthood as a rational adaptation to changes in society. These findings suggest that increased information about the limitations of human reproduction is needed, but also that societal support for younger parents is of utmost importance.  相似文献   
65.
BackgroundSkin derived precursors (SKP) comprise a subset of specialized dermal cells that can be distinguished from fibroblast by their capacity for spheroidal growth. Recent investigations have shown that hair follicles constitute a niche for this cell type, but their localization and their definite function in non-follicular skin remains largely unknown.ObjectiveTo identify the dermal niche of non-follicular SKPs and to analyze whether functional aspects correlate with this localization.MethodsSKPs were isolated from separate anatomical regions of human abdominal skin. Fluorescence activated cell sorting then was used to obtain a pure population of non-follicular SKPs. Functional characterization of these cells was performed applying differentiation and proliferation assays. Information on specific in vivo functions was derived from histological evaluation of quantity and localization patterns.ResultsSphere forming capacity and differentiation assays show that SKPs reside in the papillary part of the dermis. Further delineation revealed that the dermal capillaries represent a niche for these cells which subsequently could be isolated by FACS utilizing a perivascular marker. Whereas functional properties described for follicular SKPs could also be detected in the perivascular SKP population, histological analyses additionally point to a cross-talk with epidermal stem cells and a reduction during chronological aging.ConclusionOur data show that SKPs isolated from non-follicular skin originate from a perivascular niche. Compared to their follicular counterparts, no functional differences could be observed upon cultivation, but ex vivo analyses also point to unique functions and a contribution to the phenotype of aged skin.  相似文献   
66.
Multiple chromosomal regions and polymorphisms of several candidate genes have been linked to or associated with atopic diseases (hayfever, asthma, allergic eczema and rhinitis). In this mini-review, we present data demonstrating that the genetic regulation of the inflammatory response makes a major contribution to the risk of atopy. These data also suggest that the quantity (or quality) of the inflammation affects the priming phase of atopy, i.e., that induced by allergens or infectious agents in early childhood.  相似文献   
67.
68.
69.
ABSTRACT: BACKGROUND: Socioeconomic inequalities in cardiovascular disease are pervasive, yet much remains to be understood about how they originate. The objective of this study was to explore the relations of socioeconomic status to lipid and glucose metabolism as indicators of cardiovascular health in 5-6 year olds. Additionally to explore the explanatory role of maternal factors, birth outcome, and child factors. METHODS: In 1308 5-6 year old ethnic Dutch children from the ABCD cohort study, lipids (cholesterol, LDL, HDL, triglycerides), glucose and C-peptide were measured after an overnight-fast. RESULTS: There were no differences in cholesterol, HDL, LDL, and triglycerides between socioeconomic groups, as indicated by maternal education and income adequacy. However, children of low educated mothers had on average a higher glucose (beta = 0.15; 95% confidence interval (CI) 0.03 - 0.27), logC-peptide (beta = 0.07; 95% CI 0.04 - 0.09), and calculated insulin resistance (HOMA-IR) (beta = 0.15; 95% CI 0.08 - 0.22) compared to children of high educated mothers. Only childhood BMI partly explained these differences (models controlled for age, height, and sex). CONCLUSIONS: The socioeconomic gradient in cardiovascular risk factors seems to emerge in early childhood. In absence of underlying mechanisms these empirical findings are relevant for public health care and further explanatory research.  相似文献   
70.
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