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   1525篇
  免费   184篇
  国内免费   13篇
耳鼻咽喉   11篇
儿科学   34篇
妇产科学   20篇
基础医学   163篇
口腔科学   27篇
临床医学   176篇
内科学   783篇
皮肤病学   6篇
神经病学   50篇
特种医学   102篇
外科学   92篇
综合类   46篇
一般理论   1篇
预防医学   90篇
眼科学   3篇
药学   86篇
中国医学   1篇
肿瘤学   31篇
  2023年   28篇
  2022年   8篇
  2021年   13篇
  2020年   19篇
  2019年   27篇
  2018年   40篇
  2017年   20篇
  2016年   35篇
  2015年   30篇
  2014年   31篇
  2013年   44篇
  2012年   57篇
  2011年   70篇
  2010年   57篇
  2009年   60篇
  2008年   62篇
  2007年   84篇
  2006年   77篇
  2005年   76篇
  2004年   60篇
  2003年   52篇
  2002年   57篇
  2001年   70篇
  2000年   64篇
  1999年   54篇
  1998年   50篇
  1997年   42篇
  1996年   38篇
  1995年   32篇
  1994年   28篇
  1993年   27篇
  1992年   23篇
  1991年   20篇
  1990年   35篇
  1989年   37篇
  1988年   30篇
  1987年   32篇
  1986年   24篇
  1985年   16篇
  1984年   8篇
  1983年   10篇
  1982年   8篇
  1981年   6篇
  1980年   5篇
  1978年   9篇
  1977年   7篇
  1976年   5篇
  1975年   8篇
  1968年   3篇
  1967年   3篇
排序方式: 共有1722条查询结果,搜索用时 15 毫秒
1.
Trends in analgesic self-poisoning in West-Fife, 1971-1985   总被引:1,自引:0,他引:1  
All admissions for analgesic self-poisoning to a district poisons unit over a 15-year period have been reviewed. During this time overdose with analgesic drugs increased to represent almost half of all admissions for self-poisoning. The types of analgesics taken in overdose also changed significantly during the period of this review. Aspirin and Distalgesic poisoning declined in incidence and more cases of self-poisoning by paracetamol and non-steroidal anti-inflammatory agents were seen. The impact of these changes on the medical management and outcome of deliberate self-poisoning is analysed. The reasons behind the trends described in this paper are assessed and their implications for future prevention and treatment are discussed.  相似文献   
2.
3.
4.
Heart failure is a syndrome of breathlessness, fatigue and oedema. The effects of ageing on myocardial function and the prevalence of often multiple cardiac pathologies makes heart failure a disease of the elderly, usually characterized by primary or secondary myocardial systolic dysfunction. Appropriate treatment, which requires precise diagnosis, involves correction of precipitating or aggravating factors and the rational use of drug therapy. Diuretics and ACE inhibitors offer a combination of both symptom control and improvement in prognosis. Other agents such as digoxin, xamoterol and nitrates may be particularly useful in the treatment of patients with associated problems such as atrial fibrillation and angina. Because both ageing and heart failure may alter pharmacokinetics and pharmacodynamics, safe and effective treatment of heart failure in the elderly requires understanding of the clinical pharmacology of the drugs used.  相似文献   
5.
6.
报道了氯仿重结晶的棉酚的化学性质,样品在不同温度下干燥恒重后,经熔点、薄层层析、紫外光谱、红外光谱、X-射线衍射、热重量分析、元素(C,H,Cl)分析及棉酚合量测定等一系列的分析,确证了在60℃以下棉酚与氯仿成溶剂化物(solvate)。随着干燥温度的升高或在室温长时间的贮存,此现象逐渐消失,100℃真空干燥恒重后成为纯棉酚。  相似文献   
7.
8.
The organization of spinal cord motoneurons and their innervation of axial (white) muscles in the zebrafish were studied. Motoneurons can be divided into 2 classes, primary and secondary, on the basis of their cell-body sizes and positions. Each side of each spinal segment contains 3 primary motoneurons that are uniquely identifiable as individuals by their stereotyped cell-body positions and peripheral branching patterns. Moreover, these motoneurons precisely innervate cell-specific subsets of contiguous muscle fibers in mutually exclusive regions of their own body segment. Individual muscle fibers receive inputs from a single primary motoneuron and, in addition, from up to 3 secondary motoneurons. The results demonstrate that the precision of innervation previously described in invertebrates is also present in some vertebrates.  相似文献   
9.
To determine the effects of pregnancy on the cardiovascular responses to immersion and exercise in water, 12 women completed 20 min of immersion and 20 min of bicycle ergometry at 60% predicted VO2max in 30 degrees C water during their 15th, 25th, and 35th week of pregnancy as well as 8-10 weeks post partum. Immersion lowered the resting heart rate approximately 8 bts/min (P less than 0.05). Exercise in water also resulted in a lower heart rate as compared with the same level of exercise on land (132 +/- 4 vs 149 +/- 6 bts/min; P less than 0.05). Both the rest and exercise heart rate responses were independent of duration of pregnancy or pregnancy status. Post partum exercise cardiac output averaged 9.9 +/- 0.4 l/min, significantly lower (P less than 0.05) than the 15th (12.7 +/- 0.5), 25th (14.7 +/- 0.5), or 35th week (15.1 +/- 0.7 l/min). Total peripheral resistance was greatest (P less than 0.05) post partum (657 +/- 29 dyn.s/cm5) compared with either the 15th (515 +/- 27), 25th (407 +/- 18), or 35th week (450 +/- 23). The results indicate that exercise in water lowers the heart rate compared with land exercise at the same metabolic rate. The combined effect of exercise, water, and pregnancy may elevate the cardiac output more than expected on land, but the same general pattern of exercise response will be evident throughout the duration of pregnancy. The results further suggest that water alters the heart rate and blood pressure responses such that land-derived exercise target heart rates should not be used to prescribe exercise intensity in water.  相似文献   
10.
Because of rapid advances in the treatment of chronic heart failure, four important guidelines, including those from the European Society of Cardiology, have recently been updated. This review compares and contrasts the levels of evidence and classes of recommendation given to each of the key pharmacological and device therapies advocated by these guidelines. Possible explanations for discrepancies between the guidelines are discussed. Future approaches that might clarify the grade of evidence allocated and class of recommendation made are also described.  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