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   317560篇
  免费   18567篇
  国内免费   541篇
耳鼻咽喉   4405篇
儿科学   10852篇
妇产科学   10787篇
基础医学   48327篇
口腔科学   7811篇
临床医学   25906篇
内科学   61197篇
皮肤病学   6857篇
神经病学   23311篇
特种医学   12063篇
外国民族医学   43篇
外科学   48561篇
综合类   7845篇
现状与发展   1篇
一般理论   171篇
预防医学   21550篇
眼科学   7374篇
药学   22361篇
中国医学   840篇
肿瘤学   16406篇
  2021年   3173篇
  2019年   3001篇
  2018年   4397篇
  2017年   3254篇
  2016年   3755篇
  2015年   4212篇
  2014年   5570篇
  2013年   8351篇
  2012年   10824篇
  2011年   11264篇
  2010年   7137篇
  2009年   6460篇
  2008年   10085篇
  2007年   10946篇
  2006年   10679篇
  2005年   10188篇
  2004年   9713篇
  2003年   9132篇
  2002年   8577篇
  2001年   13404篇
  2000年   13699篇
  1999年   11525篇
  1998年   3170篇
  1997年   2898篇
  1996年   2718篇
  1995年   2621篇
  1994年   2390篇
  1992年   8345篇
  1991年   8471篇
  1990年   8279篇
  1989年   8098篇
  1988年   7331篇
  1987年   7088篇
  1986年   6736篇
  1985年   6528篇
  1984年   4769篇
  1983年   4132篇
  1982年   2482篇
  1979年   4428篇
  1978年   3235篇
  1977年   2737篇
  1976年   2507篇
  1975年   2840篇
  1974年   3358篇
  1973年   3364篇
  1972年   3122篇
  1971年   2957篇
  1970年   2841篇
  1969年   2585篇
  1968年   2541篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
991.
992.
The posterior urethral valve uropathy: Results of treatment   总被引:2,自引:0,他引:2  
Nineteen children treated for posterior urethral obstruction due to congenital valve in the University of Benin Teaching Hospital, Benin City, Nigeria, over a 9-year period have been analysed. Their ages ranged from birth to 12 years. Results show that associated kidney pathology may be irreversible even after successful excision of the valve. This determines the final prognosis, which is worse the younger the child at presentation.  相似文献   
993.
994.
The role of Chlamydia pneumoniae in 110 Sudanese children with signs of acute lower respiratory tract infections (ALRI) was investigated. Four (3.6%) had evidence of C. pneumoniae infection, of whom 3 were culture-positive, while 1 had an antibody response suggesting a recent infection. IgG antibodies at a titer of ≥1:32 to C. pneumoniae, Chlamydia psittaci and Chlamydia trachomatis were detected in 27 (24.5%), 27 (24.5%) and 7 (6.4%) of the 110 ALRI cases, respectively. C. pneumoniae, C. trachomatis or C. psittaci were not detected in nasopharyngeal secretions from any of 110 patients when fluorescence-labeled specific monoclonal antibodies were used. In a seroepidemiological survey, 318 healthy Sudanese persons aged between 1 month and 67 years were studied for C. pneumoniae antibodies.  相似文献   
995.
Abdominal magnetic resonance imaging findings were reviewed in 46 patients with Gaucher disease. All patients had hepatosplenomegaly at the time of initial imaging. Splenic nodules were present in 14 patients (30%) and varied in signal intensity. These nodules were isointense on T1-weighted and hypointense on T2-weighted images. Splenic infarcts were seen in 15 patients (33%), and four of these patients (9%) also had subcapsular fluid collections. Both nodules and infarcts were present in the spleen in four patients (9%). Pathologic correlation was performed with specimens from two patients who underwent partial splenectomy. Focal areas of abnormal signal intensity were noted in the liver in nine patients (20%). They were either stellate or segmental, and may represent fibrotic septa with ischemic changes associated with aggregates of Gaucher cells. No changes were noted in the kidneys or abdominal lymph nodes.  相似文献   
996.
997.
Thirty-five plants are listed, which are used by traditional healers in the central and southern parts of Somalia. For each species are listed: the botanical name with synonyms, collection number, vernacular name, medicinal use, preparation of remedy and dosage. Results of a literature survey are also reported including medicinal use, substances isolated and pharmacological effects.  相似文献   
998.
The structural requirements for the gastric cytoprotective activity of several sesquiterpene lactones are reported. A theoretical-experimental study on the potentially active centers is carried out. The biological evaluation of reduced analogues and the simulation of the molecular interactions between these compounds and an endogenous cysteine residue suggest that the presence of a non sterically hindered Michael acceptor seems to be an essential structural requirement for the cytoprotective activity in this family of compounds. This observation suggests that cytoprotection is mediated through a Michael reaction between the sulfhydryl-containing peptides of the mucosa and Michael acceptors present in the molecules under study. This mechanism of action is in addition to and distinct from the one proposed in our previous paper, namely, that these sesquiterpenes stimulate endogenous synthesis of prostaglandins.  相似文献   
999.
The authors developed a method for drainage of the retroperitoneal space in acute destructive pancreatitis, which includes retroperitoneal advancement of tubes to the pancreatic bed. To limit the spreading of the pyonecrotic process by creating an effective withdrawal of the exudate, the drains are introduced on both sides through the space between Toldt's fascia and the colon, and additional drains are also introduced into the paracolonic space limited by Toldt's and prerenal fascias.  相似文献   
1000.
Anaemia is a serious and common problem among young children in sub-Saharan Africa. As a first step towards developing guidelines for its recognition and treatment, we conducted a study to evaluate the ability of health workers to use clinical findings to identify children with anaemia. Health care workers examined a total of 1104 children under 5 years of age at two hospital-based outpatient clinics in rural Malawi. Blood samples were taken to determine haemoglobin concentrations. Pallor of the conjunctiva, tongue, palm or nail beds was 66% sensitive and 68% specific in distinguishing children with moderate a anaemia (haemoglobin concentration, 5-8 g/dl) and 93% sensitive and 57% specific in distinguishing those with severe anaemia (haemoglobin concentration, < 5 g/dl). Even without laboratory support, which is often unavailable in rural Africa, clinical findings can identify the majority of children with anaemia.  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