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   6102篇
  免费   308篇
  国内免费   28篇
耳鼻咽喉   105篇
儿科学   222篇
妇产科学   65篇
基础医学   700篇
口腔科学   107篇
临床医学   507篇
内科学   1480篇
皮肤病学   205篇
神经病学   464篇
特种医学   211篇
外科学   992篇
综合类   75篇
预防医学   306篇
眼科学   125篇
药学   424篇
中国医学   20篇
肿瘤学   430篇
  2023年   42篇
  2022年   102篇
  2021年   231篇
  2020年   127篇
  2019年   160篇
  2018年   175篇
  2017年   130篇
  2016年   183篇
  2015年   202篇
  2014年   321篇
  2013年   371篇
  2012年   537篇
  2011年   534篇
  2010年   295篇
  2009年   249篇
  2008年   377篇
  2007年   361篇
  2006年   287篇
  2005年   319篇
  2004年   294篇
  2003年   267篇
  2002年   210篇
  2001年   59篇
  2000年   49篇
  1999年   58篇
  1998年   46篇
  1997年   48篇
  1996年   34篇
  1995年   38篇
  1994年   27篇
  1993年   21篇
  1992年   26篇
  1991年   16篇
  1990年   21篇
  1989年   19篇
  1988年   12篇
  1987年   12篇
  1986年   6篇
  1985年   15篇
  1984年   19篇
  1983年   7篇
  1982年   13篇
  1981年   13篇
  1980年   6篇
  1979年   17篇
  1978年   12篇
  1977年   11篇
  1973年   5篇
  1970年   5篇
  1969年   5篇
排序方式: 共有6438条查询结果,搜索用时 15 毫秒
91.
92.
It is generally believed that the work of Bowlby and Robertson was new and decisive in changing the hospital conditions for young children. The fact that parents in the UK and other European countries can now visit their sick child at any time they wish or even room-in is attributed to an acquaintance with Bowlby's findings and Robertson's well-known films about the potentially detrimental effects of hospital stays for young children. In this paper we shall argue that this picture is incomplete and that, historically, things were rather more intricate. Bowlby and Robertson were neither the first nor the only researchers who tried to change hospital policies. Moreover, the older hospital policies were not uniformly bad. Long before Bowlby and Robertson began their plea for reforms, several individuals and hospitals had already introduced conditions that we now still regard as exemplary. The whole change towards more liberal, flexible, and humane practices in children's wards took place over several decades and was fuelled by both worried medical doctors, pressure groups of parents, sympathetic editors of medical journals, and emerging new research findings such as those provided by Bowlby and Robertson. In that societal debate, the voices of Bowlby and Robertson were influential but not necessarily new or decisive.  相似文献   
93.
94.
BackgroundAlthough intensive blood pressure reduction has cardiovascular benefits, the absolute benefit is greater in those at higher cardiovascular disease (CVD) risk.ObjectivesThis study examined whether N-terminal pro–B-type natriuretic peptide (NT-proBNP) helps identify subjects at higher risk for CVD events across systolic blood pressure (SBP), diastolic blood pressure (DBP), or pulse pressure (PP) categories.MethodsParticipants from the ARIC (Atherosclerosis Risk In Communities) study visit 4 (1996 to 98) were grouped according to SBP, DBP, or PP categories and further stratified by NT-proBNP categories. Cox regression models were used to estimate hazard ratios for incident CVD (coronary heart disease, ischemic stroke, or heart failure hospitalization) and mortality across combined NT-proBNP and/or BP categories, adjusting for CVD risk factors.ResultsThere were 9,309 participants (age: 62.6 ± 5.6 years; 58.3% women) with 2,416 CVD events over a median follow-up of 16.7 years. Within each SBP, DBP, or PP category, a higher category of NT-proBNP (100 to <300 or 300 pg/ml, compared with NT-proBNP <100 pg/ml) was associated with a graded increased risk for CVD events and mortality. Participants with SBP 130 to 139 mm Hg but NT-proBNP ≥300 pg/ml had a hazards ratio of 3.4 for CVD (95% confidence interval: 2.44 to 4.77) compared with a NT-proBNP of <100 pg/ml and SBP of 140 to 149 mm Hg.ConclusionsElevated NT-proBNP is independently associated with CVD and mortality across SBP, DBP, and PP categories and helps identify subjects at the highest risk. Participants with stage 1 hypertension but elevated NT-proBNP had greater cardiovascular risk compared with those with stage 2 SBP but lower NT-proBNP. Future studies are needed to evaluate use of biomarker-based strategies for CVD risk assessment to assist with initiation or intensification of BP treatment.  相似文献   
95.
96.
97.
98.
Spina bifida (SB) affects children worldwide. Studies from developed nations have explored the impact of SB on the quality of life of children and their parents. However, there are no such studies available from developing countries. We have therefore undertaken to document the impact of the disability on the families of affected children in Kenya. A questionnaire was administered to 40 mothers and their children, who were receiving treatment for SB at our institution. The results of this study should indicate where community and governmental resources and educational efforts for the disabled should be directed.  相似文献   
99.
Medullary thyroid cancer (MTC) shares biochemical features with other neuroendocrine tumors but the particular characteristics are largely unexplored. We investigated the biochemical neuroendocrine profile of MTC and whether specific markers could be useful in follow-up. In addition to the standard tumor marker calcitonin, plasma carcino-embryonic antigen (CEA), plasma catecholamines, (platelet) serotonin, chromogranin A, tryptase, and urinary markers of catecholamine, histamine, and serotonin metabolism were prospectively determined in 46 patients with histologically proven MTC. Patients were divided according to the stage of disease: group 1, no evidence; group 2, stable disease (SD); and group 3, progressive disease (PD). Plasma dopamine was increased in the majority of the patients with SD and PD; however it did not correlate with extent of disease. Elevated plasma platelet levels of serotonin were only present in patients with multiple endocrine neoplasia 2 with SD or PD but did not differ between those groups. Histamine metabolites were elevated in 20% of patients with SD and PD. In addition to plasma calcitonin, only CEA and chromogranin A could differentiate between stable and progressive MTC. MTCs are capable of synthesizing catecholamines, serotonin, and histamine metabolites underscoring that MTCs have metabolic characteristics in common with other neuroendocrine tumors. Thus far, clinical usefulness and relevance seems limited. The most useful markers in the follow-up of MTC are plasma calcitonin and CEA.  相似文献   
100.
FOXP3+ Tregs are central for the maintenance of self-tolerance and can be defective in autoimmunity. In multiple sclerosis and type-1 diabetes, dysfunctional self-tolerance is partially mediated by a population of IFNγ-secreting Tregs. It was previously reported that increased NaCl concentrations promote the induction of proinflammatory Th17 cells and that high-salt diets exacerbate experimental models of autoimmunity. Here, we have shown that increasing NaCl, either in vitro or in murine models via diet, markedly impairs Treg function. NaCl increased IFNγ secretion in Tregs, and reducing IFNγ — either by neutralization with anti-IFNγ antibodies or shRNA-mediated knockdown — restored suppressive activity in Tregs. The heightened IFNγ secretion and loss of Treg function were mediated by the serum/glucocorticoid-regulated kinase (SGK1). A high-salt diet also impaired human Treg function and was associated with the induction of IFNγ-secreting Tregs in a xenogeneic graft-versus-host disease model and in adoptive transfer models of experimental colitis. Our results demonstrate a putative role for an environmental factor that promotes autoimmunity by inducing proinflammatory responses in CD4 effector cells and Treg pathways.  相似文献   
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