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   1401篇
  免费   130篇
  国内免费   28篇
耳鼻咽喉   2篇
儿科学   67篇
妇产科学   33篇
基础医学   145篇
口腔科学   28篇
临床医学   144篇
内科学   265篇
皮肤病学   26篇
神经病学   106篇
特种医学   172篇
外科学   164篇
综合类   144篇
预防医学   51篇
眼科学   6篇
药学   156篇
  1篇
肿瘤学   49篇
  2023年   11篇
  2021年   17篇
  2020年   13篇
  2019年   11篇
  2018年   18篇
  2017年   18篇
  2016年   20篇
  2015年   17篇
  2014年   25篇
  2013年   47篇
  2012年   42篇
  2011年   55篇
  2010年   48篇
  2009年   47篇
  2008年   57篇
  2007年   62篇
  2006年   49篇
  2005年   48篇
  2004年   43篇
  2003年   40篇
  2002年   38篇
  2001年   36篇
  2000年   48篇
  1999年   49篇
  1998年   50篇
  1997年   44篇
  1996年   52篇
  1995年   28篇
  1994年   30篇
  1993年   39篇
  1992年   30篇
  1991年   23篇
  1990年   22篇
  1989年   47篇
  1988年   43篇
  1987年   33篇
  1986年   36篇
  1985年   31篇
  1984年   14篇
  1983年   7篇
  1982年   21篇
  1981年   9篇
  1980年   17篇
  1979年   13篇
  1978年   15篇
  1977年   22篇
  1976年   15篇
  1975年   7篇
  1972年   8篇
  1971年   6篇
排序方式: 共有1559条查询结果,搜索用时 31 毫秒
1.
2.
BACKGROUND: We have seen several patients with itchy lichenified plaques located bilaterally on the elbows and/or knees and have named this condition 'psoriatic neurodermatitis' (PN). OBJECTIVE: The purpose of this study was to compare clinical and histopathological characteristics of these patients to those of patients with typical lichen simplex chronicus (LSC). METHODS: Nineteen patients with PN and 34 patients with typical LSC were included. Besides clinical dermatological evaluation, the prick test was carried out on 49 patients; the Phadiatop test on 40 patients; the patch test with European standard series on 47 patients; histopathological evaluation on 39 patients; and clinical psychiatric examination on 38 patients. RESULTS: Almost exclusively, PN was seen in females and was located on the extremities. It caused more plaques than typical LSC did. In PN, the plaques were smaller, sharper, more keratotic and less excoriated, and had fewer lichenoid papules around them. Itching was usually more severe in the evening, while resting and in a hot environment in typical LSC, but not in PN. In plaques of PN, microabscesses in the horny layer, hypogranulosis, regular acanthosis and thinning of the suprapapillary plates were more frequent, and hyperpigmentation in the basal layer was less. In patients with PN, depressive disorder was found more frequently; and generalized anxiety disorder or psychosomatic characteristics, less. There were no significant differences in the results of prick, Phadiatop and patch tests between patients with PN and those with typical LSC. CONCLUSION: In our opinion, it is most likely that the so-called PN is itchy psoriasis superimposed by LSC.  相似文献   
3.
4.
Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/− 11 × 10(9) per L as compared with counts of 16 +/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/− 810 and 10,010 +/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/− 9 and 13 +/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/− 1410 and 1520 +/− 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
5.
1. The P1-purinoceptors mediating relaxation of the rat duodenum and inhibition of contraction of the rat urinary bladder were characterized by use of adenosine and its analogues 5'-N-ethylcarboxamidoadenosine (NECA), N6-cyclopentyladenosine (CPA) and 2-p-((carboxyethyl)phenethylamino)-5'- carboxamidoadenosine (CGS 21680), as well as the A1-selective antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX). The stable analogue of adenosine 5'-triphosphate (ATP), adenylyl 5'-(beta,gamma-methylene)diphosphonate (AMPPCP), was also used as previous work had indicated that it has a direct action on some P1 receptors in addition to its P2-purinoceptor activity. 2. In the rat duodenum, the order of potency of the adenosine agonists was NECA greater than or equal to CPA greater than AMPPCP = adenosine greater than CGS 21680, and DPCPX antagonized CPA and AMPPCP at a concentration of 1 nM whereas equivalent antagonism of NECA and adenosine required a concentration of 1 microM. This suggests the presence of a mixture of A1 and A2 receptors in this tissue, with CPA and AMPPCP acting on the A1 and NECA and adenosine acting on the A2 receptors. 3. In the rat bladder, the order of potency of the adenosine agonists for inhibition of carbachol-induced contractions was NECA much greater than adenosine greater than CPA = CGS 21680, and a concentration of DPCPX of 1 microM was required to antagonize responses to NECA and adenosine. This suggests the presence of A2 receptors in this tissue.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
6.
Image-directed neurosurgery.   总被引:1,自引:0,他引:1  
  相似文献   
7.
8.
Congenital dislocation of the hip (CDH) in an adult can accompany or cause mechanical low-back pain. This in turn, can create confusion in making the proper diagnosis. The mechanical alterations caused by CDH create an added strain to the lumbosacral spine. Manipulative treatment for back pain in these patients must not subject the dislocated hips to undue torque.  相似文献   
9.
OBJECTIVE--It was hypothesised that the endometrium might act as a reservoir for candida, thus infecting the vagina as the endometrium is shed during menstruation. DESIGN--A prospective study of women with recurrent vulvo-vaginal candidiasis. The endometrium was sampled and cultured for candida species. SETTING--Central London STD clinic. SUBJECTS--26 women were enrolled, of whom 20 completed the study. RESULTS--One patient had a positive endometrial culture for candida species, the isolate being Candida krusei. CONCLUSIONS--The endometrium is not a common resevoir for candida species and therefore, infection at this site is an unlikely cause of recurrent vaginal candidiasis.  相似文献   
10.
Solitary bronchioloalveolar carcinoma: CT criteria   总被引:14,自引:0,他引:14  
The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.  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