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   1831篇
  免费   241篇
  国内免费   49篇
耳鼻咽喉   11篇
儿科学   136篇
妇产科学   40篇
基础医学   172篇
口腔科学   58篇
临床医学   192篇
内科学   496篇
皮肤病学   40篇
神经病学   119篇
特种医学   203篇
外科学   178篇
综合类   120篇
预防医学   99篇
眼科学   15篇
药学   165篇
中国医学   3篇
肿瘤学   74篇
  2023年   22篇
  2022年   15篇
  2021年   38篇
  2020年   31篇
  2019年   19篇
  2018年   30篇
  2017年   51篇
  2016年   51篇
  2015年   40篇
  2014年   77篇
  2013年   93篇
  2012年   44篇
  2011年   60篇
  2010年   84篇
  2009年   81篇
  2008年   57篇
  2007年   90篇
  2006年   58篇
  2005年   55篇
  2004年   46篇
  2003年   39篇
  2002年   36篇
  2001年   52篇
  2000年   49篇
  1999年   53篇
  1998年   87篇
  1997年   71篇
  1996年   72篇
  1995年   54篇
  1994年   54篇
  1993年   60篇
  1992年   31篇
  1991年   21篇
  1990年   31篇
  1989年   45篇
  1988年   48篇
  1987年   31篇
  1986年   34篇
  1985年   30篇
  1984年   18篇
  1983年   14篇
  1982年   13篇
  1980年   13篇
  1979年   15篇
  1978年   15篇
  1977年   18篇
  1976年   18篇
  1975年   9篇
  1972年   8篇
  1971年   6篇
排序方式: 共有2121条查询结果,搜索用时 15 毫秒
1.
2.
3.
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   
4.
Image-directed neurosurgery.   总被引:1,自引:0,他引:1  
  相似文献   
5.
6.
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   
7.
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   
8.
Calciphylaxis – a topical overview   总被引:3,自引:0,他引:3  
'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis.  相似文献   
9.

Backround  

Diverticulosis is a common disease in the western society with an incidence of 33–66%. 10–25% of these patients will develop diverticulitis. In order to prevent a high-risk acute operation it is advised to perform elective sigmoid resection after two episodes of diverticulitis in the elderly patient or after one episode in the younger (< 50 years) patient. Open sigmoid resection is still the gold standard, but laparoscopic colon resections seem to have certain advantages over open procedures. On the other hand, a double blind investigation has never been performed. The Sigma-trial is designed to evaluate the presumed advantages of laparoscopic over open sigmoid resections in patients with symptomatic diverticulitis.  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