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   3226篇
  免费   195篇
  国内免费   14篇
耳鼻咽喉   14篇
儿科学   95篇
妇产科学   60篇
基础医学   422篇
口腔科学   33篇
临床医学   382篇
内科学   764篇
皮肤病学   37篇
神经病学   412篇
特种医学   268篇
外科学   301篇
综合类   49篇
一般理论   1篇
预防医学   249篇
眼科学   71篇
药学   148篇
中国医学   6篇
肿瘤学   123篇
  2023年   14篇
  2022年   16篇
  2021年   41篇
  2020年   27篇
  2019年   55篇
  2018年   60篇
  2017年   44篇
  2016年   76篇
  2015年   85篇
  2014年   85篇
  2013年   131篇
  2012年   152篇
  2011年   144篇
  2010年   98篇
  2009年   91篇
  2008年   158篇
  2007年   141篇
  2006年   151篇
  2005年   148篇
  2004年   118篇
  2003年   122篇
  2002年   98篇
  2001年   114篇
  2000年   98篇
  1999年   89篇
  1998年   48篇
  1997年   66篇
  1996年   56篇
  1995年   51篇
  1994年   42篇
  1993年   37篇
  1992年   55篇
  1991年   58篇
  1990年   54篇
  1989年   67篇
  1988年   70篇
  1987年   55篇
  1986年   54篇
  1985年   34篇
  1984年   33篇
  1983年   33篇
  1982年   21篇
  1981年   14篇
  1980年   14篇
  1979年   21篇
  1978年   16篇
  1977年   15篇
  1975年   18篇
  1971年   17篇
  1968年   13篇
排序方式: 共有3435条查询结果,搜索用时 15 毫秒
71.

Purpose  

This study aimed to identify themes associated with role conflicts and moral distress experienced by cardiovascular implantable electronic device (CIED) industry-employed allied professionals (IEAPs) in the clinical setting.  相似文献   
72.
73.
74.
The purpose of this study was to learn the reasons why individuals relocate and whether relocaters differ from nonrelocaters on demographic, social, and personality factors. One hundred participants from three age groups, 34 to 46 (young/middle-aged), 54 to 66 (young-old), and 69 to 93 (older) years, were designated as relocaters or residents as a function of months of residence. Relocaters did not differ from residents in age, income, health, or marital status. Reasons provided for relocating revealed the following differences: young/middle-aged moved for employ ment reasons, young-old moved for reasons of retirement, and older adults relocated to be closer to family members. No differences in network size occurred and older relocaters selected more cards in a social partner selection task. Most interesting was the finding that relocaters scored higher on Openness to Experience and future orientation. These data suggest personality may be an important trait that explains why some individuals are more likely to relocate.  相似文献   
75.
Aims:  Gastrointestinal stromal tumours (GISTs) display genetic alterations on chromosome 22. GTn repeat (GTn) length polymorphism in the promoter of haeme oxygenase-1 gene ( HMOX-1 ) is located on chromosome 22 and associated with malignant growth. The aim was to investigate the role of HMOX-1 promoter polymorphism in GIST patients.
Methods and results:  Tumour and corresponding healthy tissue DNA of 44 patients who underwent surgical resection of GIST were analysed by polymerase chain reaction, capillary electrophoresis and DNA sequencing. GTn polymorphism was classified into short (S) and long (L) allele. There was no difference detected in GTn genotype between tumour and healthy tissue DNA. Short GTn allele (SGTn) was significantly associated with metastatic disease, higher tumour recurrence rates and high risk GIST (consensus criteria 2001). Furthermore, SGTn allele carriers had significantly shorter disease-free and overall survival (log rank test, P  < 0.0001). On multivariate Cox regression analysis, GTn polymorphism was identified as an independent prognostic factor for survival ( P  = 0.001).
Conclusions:  HMOX-1 promoter GTn polymorphism is a potential prognostic marker and may help to allocate patients to different risk groups, customized therapy and follow-up. Haeme oxygenase-1 could represent an important candidate gene in the pathogenesis and growth of GIST.  相似文献   
76.

Purpose of Review

This review examines recent randomized clinical trials evaluating the role of coenzyme Q10 (CoQ10) in the management of coronary heart disease.

Recent Findings

CoQ10 is one of the most commonly used dietary supplements in the USA. Due to its antioxidant and anti-inflammatory effects, CoQ10 has been studied extensively for possible use in managing coronary heart disease. One of the most common applications of CoQ10 is to mitigate statin-associated muscle symptoms (SAMS) based on the theory that SAMS are caused by statin depletion of CoQ10 in the muscle. Although previous studies of CoQ10 for SAMS have produced mixed results, CoQ10 appears to be safe. Because CoQ10 is a cofactor in the generation of adenosine triphosphate, supplementation has also recently been studied in patients with heart failure, which is inherently an energy deprived state. The Q-SYMBIO trial found that CoQ10 supplementation in patients with heart failure not only improved functional capacity, but also significantly reduced cardiovascular events and mortality. Despite these positive findings, a larger prospective trial is warranted to support routine use of CoQ10. Less impressive are the effects of CoQ10 on specific cardiovascular risk factors such as blood pressure, dyslipidemia, and glycemic control.

Summary

Current evidence does not support routine use of CoQ10 in patients with coronary heart disease. Additional studies are warranted to fully determine the benefit of CoQ10 in patients with heart failure before including it in guideline-directed medical therapy.
  相似文献   
77.
Bagby  GC Jr; McCall  E; Bergstrom  KA; Burger  D 《Blood》1983,62(3):663-668
Human umbilical vein endothelial cells were cultured in supernatants of peripheral blood monocytes that had been cultured for 3 days with and without lactoferrin. Colony-stimulating activity (CSA) was measured in supernatants of the endothelial cell cultures and appropriate control cultures using normal, T-lymphocyte-depleted, phagocyte-depleted, low- density bone marrow cells in colony growth (CFU-GM) assays. Monocyte- conditioned medium contained a nondialyzable, heat labile factor that enhanced 4-15--fold the production of CSA by endothelial cells. The addition of lactoferrin to monocyte cultures reduced the activity of this monokine by 69%. Lactoferrin did not inhibit CSA production by monokine-stimulated endothelial cells. Therefore, vascular endothelial cells are potent sources of CSA, the production of CSA by these cells is regulated by a stimulatory monokine, and the production and/or release of the monokine is inhibited by lactoferrin, a neutrophil- derived putative feedback inhibitor of granulopoiesis. Inasmuch as a similar monokine is known to stimulate CSA production by fibroblasts and T lymphocytes, we suggest that mononuclear phagocytes play a pivotal role in the regulation of granulopoiesis by recruiting a variety of cell types to produce CSA.  相似文献   
78.
AIMS: To investigate the association between apolipoprotein B (apoB), A-I (apoA-I), the apoB/apoA-I ratio, and the incidence of coronary events. METHODS AND RESULTS: Analysis included 1414 men and 1436 women aged 35-64 years without a prior coronary event who participated in the population-based MONICA Augsburg survey 1984-85 (median followed-up period 13 years). Incidence of fatal and non-fatal myocardial infarction, and sudden cardiac death was assessed using data of the MONICA/KORA Augsburg coronary event registry. During follow-up, 114 incident coronary events occurred in men and 31 in women. In multivariable analysis, an increase of 1 standard deviation in the serum concentration of apoB was associated with an increased risk of coronary events in men [hazard ratio (HR)=1.49; 95% confidence interval (CI); 1.25-1.78] and in women (HR=1.73; 95% CI; 1.32-2.27). By contrast, elevated concentrations of apoA-I were not associated with a significantly decreased risk of coronary events in either sex (HR=0.91). Furthermore, the predictive power of the apoB/apoA-I ratio was similar to that of the total cholesterol/HDL cholesterol ratio in men and women. CONCLUSION: ApoB and the apoB/apoA-I ratio were strong predictors of coronary events in middle-aged men and women, whereas apoA-I did not add significantly to the estimation of future coronary risk.  相似文献   
79.
80.
目的:对比初次和再发骨质疏松性椎体压缩骨折(osteoporotic vertebral compression fractures,OVCFs)患者保 守治疗的生存质量,了解再次骨折对此类患者生存质量各方面的影响。方法:回顾性观察治疗OVCFs后出现再骨折 的患者30名(再骨折组)和同时期行保守治疗OVCFs后未发生再骨折的基本条件相似的患者30例(对照组),比较两组出 院后3个月时SF-36简明健康健康状况调查表的调查结果。结果:再骨折组治疗后的8个维度均不同程度较对照组变差 (均P<0.01)。结论:再骨折组患者的生存质量明显低于对照组,并且会进一步影响患者的心理预期、情绪和社会活动 的各个方面。  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