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   1959篇
  免费   194篇
  国内免费   6篇
耳鼻咽喉   48篇
儿科学   60篇
妇产科学   16篇
基础医学   248篇
口腔科学   19篇
临床医学   202篇
内科学   267篇
皮肤病学   37篇
神经病学   144篇
特种医学   237篇
外科学   257篇
综合类   61篇
一般理论   2篇
预防医学   201篇
眼科学   97篇
药学   135篇
中国医学   1篇
肿瘤学   127篇
  2021年   39篇
  2020年   21篇
  2019年   30篇
  2018年   46篇
  2017年   19篇
  2016年   29篇
  2015年   26篇
  2014年   49篇
  2013年   56篇
  2012年   76篇
  2011年   101篇
  2010年   63篇
  2009年   56篇
  2008年   81篇
  2007年   84篇
  2006年   86篇
  2005年   80篇
  2004年   92篇
  2003年   68篇
  2002年   58篇
  2001年   50篇
  2000年   45篇
  1999年   37篇
  1998年   30篇
  1996年   26篇
  1995年   21篇
  1994年   22篇
  1993年   19篇
  1992年   40篇
  1991年   38篇
  1990年   50篇
  1989年   42篇
  1988年   39篇
  1987年   34篇
  1986年   47篇
  1985年   24篇
  1984年   22篇
  1983年   22篇
  1982年   17篇
  1980年   17篇
  1979年   23篇
  1978年   23篇
  1977年   21篇
  1976年   17篇
  1973年   21篇
  1972年   23篇
  1971年   19篇
  1969年   18篇
  1968年   24篇
  1967年   24篇
排序方式: 共有2159条查询结果,搜索用时 15 毫秒
1.
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.  相似文献   
2.
Vasopressin (AVP) receptor binding within hypothalamic sites was compared between cycling and lactating female golden hamsters. The density of AVP receptor binding was analyzed by quantitative autoradiography within the ventrolateral hypothalamus and dorsomedial hypothalamic nucleus. Lactation was correlated with a disappearance of AVP receptor binding within the ventrolateral hypothalamus. In contrast, lactation was associated with a two- to three-fold increase in the density of AVP receptor binding within the dorsomedial hypothalamic nucleus. These results suggest that AVP receptor binding within the ventrolateral hypothalamus is responsive to gonadal hormones in female golden hamsters. However, the increase in binding observed within the dorsomedial hypothalamus may be related to other neurobiological changes associated with lactation.  相似文献   
3.
Early glottic carcinoma, specifically stage I or II, can be treated with endoscopic excision, radiation therapy, or open partial laryngectomy. Over the past two decades, this topic has received intensive interest, and controversies have often focused on techniques and outcomes comparing the use of endoscopic excision versus radiation therapy. This article will discuss philosophy, techniques, and outcomes of resection using the endoscopic approach to early glottic carcinoma. Optimization through appropriate instrumentation, staging, and technical details are critical to postoperative oncologic and vocal outcomes. The reader must remember that over 90% of T1 lesions and approximately 75% of T2 lesions are curable, and therefore adherence to the principles described below is important to achieve these outcomes.  相似文献   
4.
5.
Medial border of the perirenal space: CT and anatomic correlation   总被引:11,自引:0,他引:11  
  相似文献   
6.
Circannual variation in lymphocyte subsets, revisited   总被引:2,自引:0,他引:2  
BACKGROUND: Circadian and circannual variations in lymphocyte subsets, especially CD8+ T-lymphocytes, have been reported. This study focuses on CD4+ T-lymphocyte seasonal variation over a 6-year 8-month period. STUDY DESIGN AND METHODS: Lymphocyte subsets were quantitated monthly for four healthy individuals from 1986 through 1992 as part of a flow cytometry quality-control program. RESULTS: In general, there were no significant seasonal changes in the total number of white cells or in total lymphocyte counts. The absolute numbers of CD4+ T-lymphocytes were lowest in summer when the CD8+ T-lymphocytes were highest. Mean CD4+ T-lymphocyte counts were 846, 967, 618, and 695 per microL for Subjects 1 through 4, respectively, in winter and 432, 670, 355, and 766 per microL, respectively, in summer. Two healthy subjects had CD4+ T-lymphocyte counts lower than 300 per microL on one or more occasions during the study period. In three of the four subjects, the percentage of B-lymphocytes in winter was almost double that in summer. In one of the four subjects, no circannual rhythm was observed in these lymphocyte subpopulations. CONCLUSION: The seasonal variation in CD4+ T- lymphocyte counts demonstrated in three healthy individuals over almost 7 years is again of interest in light of renewed consideration of using surrogate tests, such as CD4+ T-lymphocyte counts, to screen for AIDS- like diseases that may be in the blood supply.  相似文献   
7.
8.
Results are reported from a parallel analysis of the association of passive smoking with respiratory symptoms and lung function (FEV1, FVC and FEV1/FVC) in 2220 US and 3855 French women from the general population examined over the same time period using similar methods. Age, city, educational level, occupational exposure and height (for lung function) were taken into account. In the US survey, being a never smoker married to a current or former smoker was significantly associated only with wheezing compared to being a true never smoker. A borderline significant association between passive smoking and dyspnoea was observed among women older than 40 in the French survey. No association was observed with cough or phlegm production. Passive smoking was significantly related to lower FVC and FEV1 values among French women 40 years or more, even among those without a history of wheeze or asthma. However, even among US women older than 40 years of age, there was no significant association between passive smoking and level of lung function. Better housing conditions, higher divorce rates, more frequent exposure to passive smoking in childhood, and different selection factors for active smoking in the US compared to France might explain the lack of association of current spousal smoking habits with lower lung function in American women.  相似文献   
9.
We measured retinal vessel diameter before and after panretinal photocoagulation in 59 eyes with diabetic retinopathy and moderate to severe optic disk neovascularization. Treatment significantly reduced mean arteriolar and venular diameter. The diameter of the retinal arterioles after treatment correlated significantly with the amount of regression in disk neovascularization. Eyes with large diameter vessels after treatment usually had little or no regression of proliferative retinopathy, whereas regression was more frequently seen in eyes with smaller diameter vessels after treatment.  相似文献   
10.
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