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   518735篇
  免费   33671篇
  国内免费   636篇
耳鼻咽喉   6924篇
儿科学   16978篇
妇产科学   13620篇
基础医学   85752篇
口腔科学   14542篇
临床医学   44723篇
内科学   94946篇
皮肤病学   12275篇
神经病学   36676篇
特种医学   18515篇
外国民族医学   63篇
外科学   77379篇
综合类   8491篇
一般理论   121篇
预防医学   39434篇
眼科学   12241篇
药学   40830篇
中国医学   1047篇
肿瘤学   28485篇
  2018年   5123篇
  2016年   4227篇
  2015年   4685篇
  2014年   6271篇
  2013年   9817篇
  2012年   13272篇
  2011年   14703篇
  2010年   8465篇
  2009年   7930篇
  2008年   13975篇
  2007年   14939篇
  2006年   15170篇
  2005年   14555篇
  2004年   14255篇
  2003年   13566篇
  2002年   13456篇
  2001年   24087篇
  2000年   25091篇
  1999年   20581篇
  1998年   5456篇
  1997年   4737篇
  1996年   5064篇
  1995年   4645篇
  1994年   4332篇
  1992年   15743篇
  1991年   16319篇
  1990年   16429篇
  1989年   15813篇
  1988年   14584篇
  1987年   14430篇
  1986年   13603篇
  1985年   12984篇
  1984年   9630篇
  1983年   8252篇
  1982年   4574篇
  1981年   4238篇
  1979年   9427篇
  1978年   6860篇
  1977年   5778篇
  1976年   5607篇
  1975年   6401篇
  1974年   7635篇
  1973年   7133篇
  1972年   6964篇
  1971年   6685篇
  1970年   6174篇
  1969年   5891篇
  1968年   5565篇
  1967年   5013篇
  1966年   4452篇
排序方式: 共有10000条查询结果,搜索用时 29 毫秒
991.
992.
From two regions differing by the levels of incidence of hepatitis B, 2019 blood serum specimens from normal population were examined for markers of HBV infection. In Moscow, among 1040 samples examined HBsAg was found in 2.0%, anti-HBs in 10.0%, anti-HBc in the absence of HBsAg and anti-HBs in 4.5%. In the Osh Province of Kirgizstan, among 979 subjects examined the same markers were found in 10.3%, 22.4%, and 14.0%, respectively. In this area, HBsAg was detected most frequently among infants (14.9% in infants under 1 year), in whom HBs-antigenemia was combined with the presence of HBeAg in 54.5% and with anti-HBc-IgM in 69.2%. Antibody to delta antigen (anti-delta) was found in 24 (25.8%) out of 93 HBsAg-positive subjects in the Osh Province but in none of 21 subjects with HBs-antigenemia in Moscow.  相似文献   
993.
I Semsei 《Gerontology》1991,37(4):199-207
The activity of ceruloplasmin (CP) increased 3-fold in rat blood between 1 week and 20 months of age, but the difference in CP activity of adult and old rats was only 14%, which still is statistically significant (p less than 0.01). The increase in NaCl and KCl concentrations in vitro resulted in the same exponential decrease in activities of CP from both young and old animals. Turpentine-induced inflammation caused an increase in blood CP levels in both young (52%) and old (25%) animals compared to age-matched controls (p less than 0.001 and p less than 0.01, respectively). These results indicate that the antioxidant activity of CP is maintained as a function of age in rat blood, which is beneficial for preventing the increase in lipid peroxidation.  相似文献   
994.
Systemic malignancies may produce a variety of ocular manifestations, reflecting both direct infiltration of ocular tissue by neoplastic cells and secondary phenomena related to tumour-induced physiological disturbances. The diagnosis and significance of these often neglected aspects of clinical oncology are discussed.  相似文献   
995.
BACKGROUND. Latex agglutination (LA) tests are ordered frequently on cerebral spinal fluid (CSF) specimens obtained from pediatric patients to identify pathogenic bacteria as early as possible in an acute infection. METHODS. Six hundred ten LA tests were performed on 176 patients suspected of having meningitis. RESULTS. Five patients with meningitis had positive LA tests. We found that the CSF white blood cell (WBC) count, and differential were the best predictors of meningitis. CONCLUSIONS. By limiting the use of LA tests to those patients having CSF with abnormal WBC counts or with positive Gram stains, the number of tests ordered would have been reduced. This practice would greatly reduce laboratory expense.  相似文献   
996.
A new technique of choledochoenterostomy was devised to solve some of the problems of enterobiliary anastomosis with a normal calibre. The distal extremity of the common bile duct is completely surrounded by the bowel mucosa to a length of 3 cm after seromyectomy of a bowel wall rectangle of 4 × 1 cm. Experimental studies in rats and dogs demonstrated that this procedure prevents the risks of anastomotic disruption and functions like a mechanical unidirectional valve, which has great efficacy in stopping enterobiliary reflux. Studies in ten patients with obstructive jaundice with an extrahepatic biliary dilation less than 1.2 cm diameter submitted to this procedure Confirmed the experimental results. All patients were asymptomatic, without jaundice and with normalization of the liver enzymes after 2 months. The permeability of the valvular anastomosis studied by cholangiography, the HIDA 99mTc test and manometry was quite similar to other classical biliary-enteric anastomosis. In contrast, anti-reflux efficacy was only demonstrated in patients with a valvular anastomosis.  相似文献   
997.
Several sets of data suggest that specific classes of anti-DNA antibodies could be implicated in the genesis of glomerular lesions in SLE. The goal of this work is to investigate if this pathogenic role could be related to the antibodies' genetic origin--from BALB/c or NZBxNZW/F1 mice--or to their physiological origin--induced either by DNA or by polyclonal B cell activation in normal mice. For this purpose, anti-DNA antibody hybridoma clones produced from different origins were subcutaneously injected in BALB/c or NZBxNZW/F1 female mice, followed by studies of immunological parameters and kidney lesions. Results concur that the induced anti-DNA antibodies can play a role in fatal disease development, related to clonal specificity but not to the way of stimulation which was either polyclonal B cell activation or DNA immunization. Also, they emphasize the possible very lethal role of serum circulating DNA.  相似文献   
998.
999.
Particular attention is given to social and regional aspects in this report on the development of special care facilities for handicapped children, infant and child mortality in Mecklenburg, and an analysis of their causes. The restricted opportunities available for influencing the relevant conditions and for introducing prophylactic measures are described. The establishment and development of medical facilities for treating sick children in Mecklenburg are outlined, special emphasis being placed on the hospitals at Ludwigslust, the importance of Schwerin's Anna Hospital and their facilities for hospital, surgical and outpatient treatment of children.  相似文献   
1000.
A study was made of the regularities and changes in the fatty acid spectrum of total lipids of the blood serum, in interaction of carbohydrate lipid metabolism, and in the hypophyseal and thyroid system in 92 patients with the nephrotic form of acute and chronic glomerulonephritis. It has been discovered that the nephrotic form of glomerulonephritis is marked by a complex of changes in the fatty acid spectrum of the blood serum, in carbohydrate lipid metabolism at the sites of their conjunction, and in the hypophyseal and thyroid system which can be regarded as metabolic potentialities of atherosclerosis formation.  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