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   2232284篇
  免费   180767篇
  国内免费   4127篇
耳鼻咽喉   31688篇
儿科学   71048篇
妇产科学   64538篇
基础医学   318935篇
口腔科学   66321篇
临床医学   197048篇
内科学   430928篇
皮肤病学   47073篇
神经病学   181546篇
特种医学   89632篇
外国民族医学   632篇
外科学   341570篇
综合类   58593篇
现状与发展   5篇
一般理论   765篇
预防医学   174324篇
眼科学   52346篇
药学   168214篇
  3篇
中国医学   4257篇
肿瘤学   117712篇
  2018年   20496篇
  2015年   20992篇
  2014年   29268篇
  2013年   44695篇
  2012年   60324篇
  2011年   63549篇
  2010年   37422篇
  2009年   35566篇
  2008年   60550篇
  2007年   64659篇
  2006年   65114篇
  2005年   63564篇
  2004年   62556篇
  2003年   59960篇
  2002年   58413篇
  2001年   99579篇
  2000年   102589篇
  1999年   87130篇
  1998年   24699篇
  1997年   22591篇
  1996年   22462篇
  1995年   21681篇
  1994年   20486篇
  1993年   19266篇
  1992年   72677篇
  1991年   70598篇
  1990年   69108篇
  1989年   66769篇
  1988年   62467篇
  1987年   61474篇
  1986年   58469篇
  1985年   56581篇
  1984年   42911篇
  1983年   36901篇
  1982年   22505篇
  1981年   20317篇
  1980年   18978篇
  1979年   41987篇
  1978年   29637篇
  1977年   24960篇
  1976年   23291篇
  1975年   24850篇
  1974年   30649篇
  1973年   29389篇
  1972年   27299篇
  1971年   25714篇
  1970年   23882篇
  1969年   22739篇
  1968年   20647篇
  1967年   18851篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
A modified technique for the repair of moderate to severe cicatricial entropion has been developed. This method is unique, as it involves the creation of a bipedicled tarsoconjunctival advancement flap. The technique avoids the causes of surgical failure seen with standard tarsal fracturing procedures.  相似文献   
995.
With some, but not all, types and intensities of exercise, lactate accumulates in the blood and in the muscles engaged in the exercise. A great deal of attention has been directed towards attempting to understand the dynamics of lactate production and removal at the onset of exercise, during exercise, and during the recovery process following exercise. It has been hoped that an unravelling of these events would provide a key to understanding cellular metabolism and its regulation during exercise. The purpose of this introductory paper to a symposium on lactate is to present a brief overview of some of the conditions that influence the rate and magnitude of lactate accumulation during exercise. It is pointed out that many conditions influence the rate and magnitude of the accumulation of lactate in blood and muscles. Included are diet, state of physical fitness, and the type and duration of the exercise. We have cautioned against trying to evaluate the state of oxygen delivery to muscle and the state of tissue oxygenation from the appearance of lactate in blood. We have pointed out the positive aspects of lactate production based on how it augments the cellular supply of ATP, thereby allowing for high intensity exercise, and also the negative aspects that develop as a result the reduction in pH which adversely influences many cellular processes essential for muscular activity.  相似文献   
996.
The rearranged genes encoding immunoglobulin heavy (mu) and light (kappa) chains specific for the hapten 2,4,6-trinitrophenyl (Tnp) were introduced into a B-lymphoma line that bears surface IgG with an unknown specificity and expresses surface Ia molecules. A transformant expressing surface IgM specific for Tnp was obtained. The transformant was found to present Tnp-proteins to antigen (protein)-specific T cells far more efficiently than the parenteral B-lymphoma line. This artificial system, utilizing recombinant DNA technology and gene transfer, provides several approaches for the study of T-cell-B-cell interactions.  相似文献   
997.
998.
999.
Sex and racial predilection, social history, and histology were analyzed in a biopsy-proven adenocarcinoma of the lower esophagus/esophagogastric junction collected over a 5-year period in two teaching institutions with different patient populations. Adenocarcinoma occurred in 11% of patients with biopsy-proven esophageal cancer. The disease occurred only in males at one center, and in a 7:1 ratio of males to females at the other center. Clear racial predilection was seen, since 12 of 13 patients with adenocarcinoma of the esophagus were white, whereas less than 20% of patients with squamous carcinoma of the esophagus were white. The finding of Barrett's epithelium in eight of the 13 cases strongly supports the theory that in white males, Barrett's epithelium is a precursor lesion of adenocarcinoma of the esophagus/esophagogastric junction.  相似文献   
1000.
Fifteen patients with cutaneous signs and symptoms caused by adverse reactions to foods were treated in an open trial with ketotifen for 4 to 6 weeks. Seven subjects were allergic and 8 had food intolerance. Each patient was treated with a single dose of ketotifen daily: 2 mg half an hour before going to sleep. Clinical improvement was achieved in 6 out of 7 allergic patients and in 6 out of 8 patients with food intolerance. Since several drugs have been demonstrated to have an influence on immune response, the in vitro effects of ketotifen on some immunological parameters were also studied. Ketotifen showed a significant inhibitory effect on autologous mixed lymphocyte reaction responsiveness.  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