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   2349910篇
  免费   171627篇
  国内免费   3331篇
耳鼻咽喉   32062篇
儿科学   75893篇
妇产科学   62686篇
基础医学   348182篇
口腔科学   63637篇
临床医学   211368篇
内科学   457293篇
皮肤病学   51727篇
神经病学   185273篇
特种医学   88016篇
外国民族医学   489篇
外科学   353877篇
综合类   47520篇
现状与发展   12篇
一般理论   848篇
预防医学   182754篇
眼科学   54325篇
药学   175112篇
  11篇
中国医学   4575篇
肿瘤学   129208篇
  2021年   18981篇
  2019年   19536篇
  2018年   27062篇
  2017年   20362篇
  2016年   22749篇
  2015年   25644篇
  2014年   36102篇
  2013年   53959篇
  2012年   74680篇
  2011年   79415篇
  2010年   47060篇
  2009年   44568篇
  2008年   74617篇
  2007年   79483篇
  2006年   80298篇
  2005年   77782篇
  2004年   74373篇
  2003年   71696篇
  2002年   69364篇
  2001年   108743篇
  2000年   111460篇
  1999年   93495篇
  1998年   26991篇
  1997年   23661篇
  1996年   24056篇
  1995年   22715篇
  1994年   20894篇
  1993年   19713篇
  1992年   72001篇
  1991年   70071篇
  1990年   68393篇
  1989年   65665篇
  1988年   60304篇
  1987年   59129篇
  1986年   55223篇
  1985年   53005篇
  1984年   39312篇
  1983年   33396篇
  1982年   19858篇
  1979年   35867篇
  1978年   25651篇
  1977年   21231篇
  1976年   20333篇
  1975年   21819篇
  1974年   26148篇
  1973年   24804篇
  1972年   23200篇
  1971年   22037篇
  1970年   20247篇
  1969年   19315篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A patient who had right and left atrial membranes was examined. The diagnosis and the hemodynamic significance of both membranes were detailed by transesophageal echocardiography and were confirmed by magnetic resonance imaging. Transesophageal imaging was found to be superior to routine echocardiography in visualization of these atrial structures.  相似文献   
992.
Synovial fluid phospholipase A2s and inflammation.   总被引:1,自引:1,他引:0       下载免费PDF全文
The activation of phospholipase A2 is believed to have an important role in the inflammatory process owing to its induction of eicosanoids, platelet activating factor, and other mediators. Soluble phospholipase A2 has been associated with exudates in different inflammatory conditions. In this review the general physiology and control of this enzyme and, in particular, the most recent findings on human synovial fluid phospholipase A2s are discussed.  相似文献   
993.
A variety of nutritional factors influence the bioavailability of calcium and increase a woman's risk of osteoporosis. Eight healthy women completed an 8-week metabolic study designed to investigate the effect of nonalcoholic carbonated beverage consumption on calcium metabolism. Compared with women receiving a control diet, women consuming a diet high in nonalcoholic carbonated beverages demonstrated similar mean serum levels of calcium, ionized calcium, phosphorus, alkaline phosphatase, parathyroid hormone, 1,25-dihydroxyvitamin D3, and osteocalcin. Twenty-four-hour urine volume, creatinine clearance, calcium-creatinine ratio, and phosphorus-creatinine ratio were similar during consumption of the diet high in nonalcoholic carbonated beverages and the control diet. Twenty-four-hour cyclic adenosine monophosphate-creatinine ratio was significantly lower in women consuming the diet high in nonalcoholic carbonated beverage compared with women receiving the control diet (342 +/- 27.4 nmol/mmol vs 409 +/- 22.1 nmol/mmol). Consumption of a diet high in nonalcoholic carbonated beverages on a short-term basis does not appear to affect adversely the serum or urinary markers of calcium metabolism.  相似文献   
994.
A patient with chronic renal failure presenting to the emergency department with acute pulmonary edema has a true life-threatening emergency. Whereas conventional treatment modalities may prove useful, more unusual therapeutic measures may be necessary. A case is presented followed by useful recommendations for the emergency physician faced with such a patient.  相似文献   
995.
Patients suffering from pain due to osteoarthritis of the hip and knee participated in a double-blind placebo controlled trial using daily Codetron home care units for 6 weeks over the tibial, saphenous, popliteal and sciatic nerves, and tender points. Seventy-four percent of patients in the real Codetron (Group A) and 28% of the patients in sham Codetron (Group B) improved their pain level more than 25% as measured by visual analogue scale. The difference in pain improvement in the two groups was statistically significant (p less than 0.02 using Fisher's exact probability ratio). Other functional parameters proved to be insensitive to change in this study. This is highly suggestive of beneficial effect of nonhabituating Codetron as a complementary modality in the therapy of chronic pain conditions such as osteoarthritis.  相似文献   
996.
997.
This article reviews the utility of noninvasive echocardiography in the detection of early cardiac transplant rejection before and after the use of cyclosporine. It addresses the use of Doppler and two-dimensional echocardiography in the routine cardiac evaluation of the heart-transplant patient, including the use of two-dimensional echocardiography in guiding the endomyocardial biopsy procedure.  相似文献   
998.
The acute recognition and management of CHF is challenging. A basic understanding of the determinants of cardiac performance and myocardial O2 consumption along with the pathophysiology of CHF is essential knowledge for the physician undertaking to treat this serious disorder. The basic value of the patient history and physical examination along with assessment of noninvasive tests remains unquestioned, but in addition much relevant and sophisticated information can be gained by invasive hemodynamic monitoring. The cardiopulmonary profile generated by such monitoring allows the physician to use specific hemodynamic and circulatory data for the purpose of manipulating these variables favorably for the heart and circulation. A wide array of therapeutic options is currently available, but, in general, respiratory support and pharmacotherapy are the mainstays of treatment. The traditional agents like digitalis and diuretics have assumed a lesser role during the last decade because of the availability of potent new vasodilator and inotropic agents. In addition, certain mechanical, procedural, and surgical options can be used if circumstances are urgent. In the final analysis, physicians who manage these patients must possess strong cognitive skills but also the clinical reflexes to carry them out: for every hemodynamic and circulatory action, they must be prepared to counter quickly and decisively with a clinical reaction which utilizes these principles to optimize cardiac function. It is hoped that the strategies presented in this article will allow them to perform in such a manner.  相似文献   
999.
Rift Valley fever (RVF) virus infection, dissemination, and transmission rates were determined for Aedes fowleri, Aedes mcintoshi and Culex pipiens 7 or 10 days after sequentially feeding to repletion on RVF virus immune hamsters and RVF viremic hamsters, or after feeding on a mixture of RVF virus immune sheep serum and RVF viremic hamster blood through a pledget. No significant differences in infection or dissemination rates were detected among Ae. fowleri and Cx. pipiens feeding to repletion on immune hamsters before or after feeding to repletion on a viremic hamster. Similarly, no significant differences in infection, dissemination, or transmission rates were observed among Ae. fowleri and Cx. pipiens feeding to repletion on immune hamsters or nonimmune (control) hamsters 0 or 24 hr after inoculation with RVF virus. Infection rates were significantly higher for Ae. fowleri (56/66, 85%) and Cx. pipiens (123/148, 83%) fed only on viremic hamsters than for those interrupted to complete feeding on an immune hamster (Ae. fowleri [24/49, 59%], Cx. pipiens [66/131, 50%]) or a nonimmune hamster (Ae. fowleri [32/51, 63%], Cx. pipiens [69/127, 54%]). However, no significant differences were detected in infection, dissemination, or transmission rates among Ae. fowleri, Ae. mcintoshi or Cx. pipiens fed on a viremic hamster and interrupted to complete feeding on an immune vs. a nonimmune hamster. Results from interrupted feeding experiments were significantly different from pledget feeding experiments.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
1000.
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