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   1629310篇
  免费   135906篇
  国内免费   2678篇
耳鼻咽喉   21942篇
儿科学   53776篇
妇产科学   46807篇
基础医学   232103篇
口腔科学   47746篇
临床医学   144102篇
内科学   320737篇
皮肤病学   34744篇
神经病学   133265篇
特种医学   65830篇
外国民族医学   485篇
外科学   247994篇
综合类   40054篇
现状与发展   3篇
一般理论   570篇
预防医学   125341篇
眼科学   36995篇
药学   123384篇
  2篇
中国医学   3060篇
肿瘤学   88954篇
  2018年   15700篇
  2016年   13711篇
  2015年   15889篇
  2014年   21806篇
  2013年   32831篇
  2012年   44846篇
  2011年   47124篇
  2010年   27729篇
  2009年   26409篇
  2008年   44789篇
  2007年   47152篇
  2006年   47891篇
  2005年   46344篇
  2004年   45665篇
  2003年   43532篇
  2002年   42496篇
  2001年   76132篇
  2000年   78743篇
  1999年   66789篇
  1998年   18008篇
  1997年   16533篇
  1996年   16514篇
  1995年   16202篇
  1994年   15220篇
  1993年   14338篇
  1992年   55648篇
  1991年   53979篇
  1990年   52784篇
  1989年   50997篇
  1988年   47388篇
  1987年   46751篇
  1986年   44482篇
  1985年   43043篇
  1984年   32202篇
  1983年   27693篇
  1982年   16248篇
  1981年   14537篇
  1980年   13660篇
  1979年   30629篇
  1978年   21178篇
  1977年   17867篇
  1976年   16778篇
  1975年   17656篇
  1974年   21584篇
  1973年   20772篇
  1972年   18946篇
  1971年   17856篇
  1970年   16356篇
  1969年   15315篇
  1968年   14010篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
991.
992.
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   
993.
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   
994.
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   
995.
996.
997.
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   
998.
Aseptic bone necrosis is a well known complication after corticosteroid treatment in adults and several hundred cases have been reported. Alterations in fat metabolism with vascular occlusion due to fat embolization, as well as microtraumata and osteoporosis are discussed as etiologic factors. In contrast, aseptic bone necrosis in relation to corticosteroid treatment is rare in children and adolescents. We therefore report 3 patients, aged from 10 to 18 years, suffering from severe aplastic anemia, meningeal relapse after acute lymphocytic leukemia and acute myelocytic leukemia respectively, who developed aseptic bone necrosis 6, 11, and 20 months following the onset of corticoid therapy. The patients survive from 28+ to 50+ months after diagnosis of their initial hematologic disease, as it can be expected today for increasing numbers of patients. We therefore believe, that aseptic bone necrosis may represent a serious therapy related complication and suggest that, diagnostic examination in patients with suspicious complaints of the hip, shoulder or knee should also exclude the possibility of a bone necrosis after leucemic relapse has been ruled out. Since radiological changes only develop several weeks to months after the onset of the clinical symptoms and because of the disabling consequences for patients, misdiagnosed at the beginning, a 99 technetium bone scan should be done as early as possible. Corticosteroids, despite their serious side effects are still being considered as a important part of hematologic therapy and are not being omitted in the near future, so that the earliest possible diagnosis of bone necrosis will remain of great importance.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
999.
Contact lens-induced corneal warpage   总被引:1,自引:0,他引:1  
  相似文献   
1000.
A transfer procedure is very useful in the treatment of strabismus. The most common use of this procedure is to augment an already planned resection or recession procedure so that it can be performed monocularly to reduce an accompanying hypertropia or hypotropia or to collapse the A or V pattern when horizontal surgery is being performed for estropia or exotropia. In transfer procedures, the resultant change of deviation and cosmetic improvement is good or excellent in almost all cases. Some special transfer procedures, such as the Harada-Ito or the Jensen operation, can have dramatic effects on both comfort and change of symptoms for the patient.  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