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   1538580篇
  免费   125089篇
  国内免费   6941篇
耳鼻咽喉   18937篇
儿科学   48206篇
妇产科学   40357篇
基础医学   208995篇
口腔科学   40154篇
临床医学   141407篇
内科学   319445篇
皮肤病学   34696篇
神经病学   130905篇
特种医学   63930篇
外国民族医学   287篇
外科学   241111篇
综合类   33717篇
现状与发展   3篇
一般理论   580篇
预防医学   120907篇
眼科学   32932篇
药学   107038篇
  6篇
中国医学   2514篇
肿瘤学   84483篇
  2021年   13137篇
  2019年   13301篇
  2018年   18510篇
  2017年   14391篇
  2016年   16894篇
  2015年   19137篇
  2014年   26969篇
  2013年   39242篇
  2012年   50863篇
  2011年   54193篇
  2010年   32992篇
  2009年   31875篇
  2008年   50000篇
  2007年   53042篇
  2006年   53834篇
  2005年   52287篇
  2004年   49739篇
  2003年   47654篇
  2002年   45259篇
  2001年   67667篇
  2000年   69085篇
  1999年   58275篇
  1998年   19046篇
  1997年   16861篇
  1996年   17589篇
  1995年   17622篇
  1994年   16315篇
  1993年   15334篇
  1992年   47877篇
  1991年   46465篇
  1990年   44579篇
  1989年   42379篇
  1988年   39289篇
  1987年   38572篇
  1986年   36347篇
  1985年   35175篇
  1984年   27084篇
  1983年   22750篇
  1982年   14690篇
  1981年   13255篇
  1980年   12406篇
  1979年   23917篇
  1978年   17498篇
  1977年   14754篇
  1976年   13541篇
  1975年   14000篇
  1974年   16359篇
  1973年   15626篇
  1972年   14319篇
  1971年   13169篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males.  相似文献   
102.
From the early 1980s to the present, neoliberal doctrine has called for government policies of privatization, funding cutbacks, and deregulation of public health and other domestic social programs in the belief that the market rather than the public sector can best organize and distribute crucial societal services. Proponents of a neoliberal and deregulatory mixed approach of command and control and self-regulation argue this approach provides the most adequate means to conduct regulation in the legalistic and adversarial U.S. regulatory process. In April 1994, the Occupational Safety and Health Administration issued a proposed rule to eliminate tobacco smoking in most workplace rooms, arguing secondhand tobacco smoke annually killed up to 13,700 nonsmokers. The tobacco industry purposely delayed public hearing procedures (later halted altogether by Congress and the president) primarily to advance unhindered private property rights and profits rather than submitting to a public command-and-control regulatory framework to reduce deaths due to secondhand tobacco smoke.  相似文献   
103.
Atherosclerotic renal artery stenosis (ARAS) may cause hypertension, progressive renal failure, and recurrent pulmonary edema. It typically occurs in high risk patients with coexistent vascular disease elsewhere. Most patients with ARAS are likely to die from coronary heart disease or stroke before end-stage renal failure occurs. Recent controlled trials have shown that most patients undergoing angioplasty to treat renovascular hypertension still need antihypertensive agents 6 or 12 months after the procedure. Nevertheless, the number of antihypertensive agents required to control blood pressure adequately is lower following angioplasty than for medication alone. Trials assessing the value of revascularization for preserving renal function or preventing clinical events are only in the early recruitment phase. Revascularization should be undertaken in patients with ARAS and resistant hypertension or heart failure, and probably in those with rapidly deteriorating renal function or with an increase in plasma creatinine levels during angiotensin-converting enzyme inhibition. With or without revascularization, medical therapy using antihypertensive, hypolipidemic and antiplatelet agents is necessary in almost all cases.  相似文献   
104.
105.
106.
To understand in situ behavior of osteocytes, we characterized a model of osteocytes in their native bone matrix and demonstrated real-time biologic activity of osteocytes while bending the bone matrix. Using 43 male Sprague-Dawley rats, dumbbell-shaped explants were harvested from stainless steel femoral implants after 6-12 weeks and incubated in culture medium or fixed. Sixteen specimens were used to determine bone volume density (BV/TV), volumetric bone mineral density (BMD) and histology for different implantation periods. Osteocyte viability was evaluated by L-lactate dehydrogenase (LDH) activity in 12 cultured explants. Confocal microscopy was used to assess tracer diffusion in three explants and changes in osteocyte pH of a mechanically loaded explant. From 6 to 12 weeks, explant BV/TV and volumetric BMD trended up 92.5% and 101%, respectively. They were significantly and highly correlated. Tissues were uniformly intramembranous and all bone cell types were present. Explants maintained LDH activity through culture day 8. Diffusion at 200 microM was limited to 1,209 Da. Explants appeared capable of reproducing complex bone biology. This model may be useful in understanding osteocyte mechanotransduction in the context of a physiologically relevant bone matrix.  相似文献   
107.
We report the case of a patient with a 13-year history of pemphigus vulgaris (PV) treated with immunosuppressive agents, prednisone and mycophenolate mofetil who had developed lesions of Kaposi's sarcoma (KS) on a sole plaque of PV that had been previously treated with intralesional injections of steroids. The lesions were surgically removed and polymerase chain reaction (PCR) demonstrated human herpesvirus-8 (HHV-8) DNA. There were neither recurrences nor later dissemination of KS following gradual decrease of the immunosuppressive therapy. We suggest that the treatment with intralesional steroids may have influenced the local reactivation of a latent infection of the virus, determining the appearance of this localized KS.  相似文献   
108.
109.
Thoraxtrauma     
Chest injuries can be sustained in isolation or in association with multiple injuries. Life-threatening complications may ensue because organs that are vital to survival of the organism are situated within the thoracic cavity. These complications include airway obstruction, tension pneumothorax, wide open pneumothorax, flail chest, cardiac tamponade and massive hemothorax. The mortality of patients hospitalized with chest injury can be as high as 10%. Clinical examination and awareness of the possibility of other injuries (high level of suspicion) are essential, and standard chest X-ray, ultrasound and thoracic computed tomography may also be needed for the diagnosis. The first part of this serial paper on the management of chest injuries focuses on anatomical aspects, pathophysiology and symptoms, but mainly on the indications for the standard diagnostic procedures and further high-tech examinations.  相似文献   
110.
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