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   6233篇
  免费   494篇
  国内免费   12篇
耳鼻咽喉   40篇
儿科学   298篇
妇产科学   115篇
基础医学   764篇
口腔科学   117篇
临床医学   757篇
内科学   1387篇
皮肤病学   133篇
神经病学   583篇
特种医学   257篇
外国民族医学   2篇
外科学   881篇
综合类   371篇
一般理论   12篇
预防医学   493篇
眼科学   37篇
药学   221篇
  1篇
中国医学   2篇
肿瘤学   268篇
  2021年   89篇
  2019年   51篇
  2018年   65篇
  2017年   47篇
  2016年   61篇
  2015年   110篇
  2014年   134篇
  2013年   176篇
  2012年   262篇
  2011年   253篇
  2010年   190篇
  2009年   149篇
  2008年   253篇
  2007年   251篇
  2006年   265篇
  2005年   268篇
  2004年   279篇
  2003年   212篇
  2002年   258篇
  2001年   217篇
  2000年   194篇
  1999年   184篇
  1998年   76篇
  1997年   79篇
  1996年   86篇
  1995年   61篇
  1994年   59篇
  1993年   55篇
  1992年   162篇
  1991年   144篇
  1990年   153篇
  1989年   154篇
  1988年   120篇
  1987年   122篇
  1986年   114篇
  1985年   97篇
  1984年   92篇
  1983年   61篇
  1980年   45篇
  1979年   65篇
  1978年   71篇
  1977年   55篇
  1976年   63篇
  1975年   55篇
  1974年   68篇
  1973年   55篇
  1972年   49篇
  1971年   59篇
  1970年   55篇
  1969年   55篇
排序方式: 共有6739条查询结果,搜索用时 31 毫秒
1.
2.
BACKGROUND: The present study was aimed to define the gender ratio, familial occurrence, age of onset, precipitating factors, clinical types, nail and joint involvement of psoriasis in childhood and adolescence in Turkey. METHODS: A total of 61 children with psoriasis under 18 years old were evaluated retrospectively, for age, gender, age of disease onset, family history, concomitant disease, the clinical type of psoriasis, clinical localization, nail and joint involvement and treatment modalities. RESULTS: Of the patients, 23 (37.70%) were boys and 38 (62.30%) were girls. Mean age was 9.28 +/- 4.02 years in girls and 11.18 +/- 3.85 years in boys (9.96 +/- 4.03 years in all children). Mean age at the onset of the disease was 6.81 +/- 4.11 years in girls and 7.03 +/- 4.28 years in boys (6.89 +/- 4.14 years in all patients). In 14 (23%) cases, a positive family history was detected. The most frequent probable triggering factors were upper respiratory tract infections (14.8%) and positive throat culture for A group ss-hemolytic streptococcus (21.3%). Frequency of emotional stress and psychiatric morbidity were 54% and 9.8%, respectively. The most frequent localizations at onset were trunk (44.3%), extremities (54.0%), and scalp (36.0%). Three children (4.9%) had a history of dissemination from psoriatic diaper rash. In total, 51 (83.6%) patients presented with psoriasis vulgaris, eight (13.1%) with generalized pustular psoriasis, and the remaining two (3.3%) with erythrodermic psoriasis. CONCLUSION: The incidence of psoriasis among dermatological patients in childhood and adolescence was 3.8%. The disease tends to appear earlier in girls than boys. The authors suggested that stress and upper respiratory infections are the most important triggering factors in childhood and adolescence psoriasis.  相似文献   
3.
4.
5.
6.
Experience with the P.A.S.-PORT, a peripherally implanted central venous access device, is evaluated in a retrospective review of 154 patients from July 1991 to June 1994. Blood could not be aspirated from six patients. Complications included temporary minor thrombophlebitis in seven patients (4.5%), symptomatic axillary or subclavian vein thrombosis in five patients (3.2%), clotted port in two patients (1.2%), port pocket cellulitis in two patients (1.2%), and fungal sepsis in two patients (1.2%). In six patients (3.8%) the P.A.S.-PORT had to be removed because of complications. The P.A.S.-PORT facilitated delivery of chemotherapy, parenteral nutrition, blood products, antibiotics, hydration, and blood sampling. It was demonstrated that the P.A.S.-PORT may be inserted and used with a low incidence of complications in gynecologic cancer patients.  相似文献   
7.
It is unknown among first-degree relatives of individuals with insulin-dependent diabetes mellitus (IDDM) whether the disease process occurs in relatively few but always progresses to clinical IDDM or whether subclinical disease is more common but remains nonprogressive in many cases. Islet cell antibodies (ICAs) were found in 21 of 724 (2.9%) first-degree relatives during screening in the greater Seattle area between 1983 and 1988. Measures of beta-cell function (glucose disappearance rate [Kg], fasting insulin, acute insulin response to intravenous arginine [AIRarg], acute insulin response to intravenous glucose [AIRgluc], slope of glucose potentiation of AIRarg) and insulin sensitivity were obtained. Twenty individuals, 9 ICA+ relatives and 11 ICA- relatives, were evaluated prospectively. When expressed in relation to the expected AIRgluc based on each subject's sensitivity index, AIRgluc in 18 of 20 relatives fell below 100%, indicating inappropriately low insulin secretion (subclinical beta-cell dysfunction). After a median follow-up of 42 mo, 10 of 11 ICA- relatives remained ICA-. None showed deteriorating beta-cell dysfunction, and none developed diabetes. Five ICA+ relatives showed persistent immunologic positivity. beta-Cell function remained remarkably stable in all except 2 relatives. One was a 15-yr-old boy who developed IDDM shortly after screening and before evaluation of beta-cell function could be carried out. The other was an 18-yr-old monozygotic twin who developed IDDM after 27 mo. Both of these individuals had ICAs of 80 Juvenile Diabetes Foundation U and had been discordant for less than 5 yr.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
9.
10.
Human peripheral mononuclear cells responded chemotactically to 4-carboxyl-L-glutamic acid. The maximal chemotactic response occurred at 0.1 nM. No chemotactic response was found with neutrophils or fetal bovine fibroblasts. Glutamic acid, a neuroexcitatory dicarboxylic amino acid and the parent compound of 4-carboxyglutamic acid, did not stimulate chemotaxis in any of the cells tested. However, it functioned as an antagonist to 4-carboxyglutamic acid (ED50 approximately 2 pM; ED100 approximately 10 pM). In contrast to the lack of response to glutamic acid, its dicarboxylic cyclic analogue, kainic acid, excited a chemotactic response in mononuclear cells. The data suggest that mononuclear phagocytes have receptors for dicarboxylic neuroexcitatory amino acids, and we speculate that 4-carboxyglutamic acid, a tricarboxylic acid, may have a previously unrecognized role as a neuroexcitatory amino acid.  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