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   198523篇
  免费   4190篇
  国内免费   446篇
耳鼻咽喉   2792篇
儿科学   7659篇
妇产科学   5908篇
基础医学   25360篇
口腔科学   5877篇
临床医学   15382篇
内科学   35842篇
皮肤病学   4567篇
神经病学   11835篇
特种医学   10712篇
外国民族医学   97篇
外科学   30313篇
综合类   1243篇
一般理论   2篇
预防医学   16362篇
眼科学   4529篇
药学   13726篇
  2篇
中国医学   163篇
肿瘤学   10788篇
  2018年   3683篇
  2017年   3998篇
  2016年   3320篇
  2015年   4988篇
  2014年   4469篇
  2013年   3634篇
  2012年   10157篇
  2011年   5014篇
  2010年   2394篇
  2009年   3998篇
  2008年   2224篇
  2007年   2955篇
  2006年   3129篇
  2005年   11299篇
  2004年   12761篇
  2003年   8322篇
  2002年   3494篇
  2001年   4416篇
  2000年   1746篇
  1999年   5881篇
  1998年   547篇
  1995年   396篇
  1992年   6890篇
  1991年   7124篇
  1990年   7362篇
  1989年   6970篇
  1988年   6489篇
  1987年   6246篇
  1986年   5962篇
  1985年   5261篇
  1984年   3604篇
  1983年   2923篇
  1982年   1007篇
  1981年   772篇
  1980年   848篇
  1979年   3836篇
  1978年   2370篇
  1977年   1784篇
  1976年   1568篇
  1975年   2477篇
  1974年   3120篇
  1973年   2745篇
  1972年   2765篇
  1971年   2748篇
  1970年   2559篇
  1969年   2468篇
  1968年   2242篇
  1967年   2165篇
  1966年   1899篇
  1965年   1136篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
A severe foodborne outbreak of group A streptococcal disease (T28) affected 122/169 people (72%) who attended a church party or ate leftovers from the party. The median incubation time was 42 h. Muscular pain or weakness and fatigue usually preceded pharyngeal symptoms. Complications included otitis media with perforation, peritonsillitis requiring tonsillectomy, arthritis and pericarditis. A 45-year-old man died 36 h after he developed an influenza-like illness, and at necropsy there were histological signs of early streptococcal septicaemia. The strain produced erythrogenic exotoxins B and C. Streptococci were probably transmitted by sliced eggs on sandwiches. Laboratory experiments showed that there was an increment in viable count of streptococci with 6 logs after incubation in egg yolk for 24 h at room temperature. The unusually warm climate and flaws in food handling routines contributed to this large foodborne epidemic.  相似文献   
982.
983.
984.
Mechanisms of ischemic brain damage   总被引:20,自引:0,他引:20  
This article provides a brief review of recent developments regarding the pathophysiology of ischemic brain damage, and offers hypotheses explaining the pathogenesis of selective neuronal vulnerability and of tissue infarction, respectively. It is suggested that selective neuronal vulnerability, observed after brief periods of ischemia and after hypoglycemic coma, qualifies as an excitotoxic lesion, which causes postsynaptic damage to neurons innervated by excitatory amino acids by enhancing calcium influx. However, ischemic damage often involves glial and vascular cells as well, and causes infarction. It is hypothesized that this type of brain damage is related to acidosis and that enhanced acidosis is detrimental because it accelerates delocalization of protein-bound iron, with an ensuing free-radical damage to membrane lipids and proteins.  相似文献   
985.
Bellini's duct carcinoma is a very rare tumor originating from the collecting tubules of the kidney. It should be part of differential diagnosis in cases with gross hematuria, failed diagnostic proof of a tumor within the collecting system and a centrally located hypovascular mass. Analysis of the cytoskeleton by means of cytokeratin patterns enables classification as a tumor of urothelial origin.  相似文献   
986.
987.
In the period 1970-1984 alcoholic hepatitis was diagnosed by liver biopsy in 52 females. Thirty-six patients with cirrhosis were generally in a worse clinical and biochemical state than those without cirrhosis. Biochemical tests for liver function showed significant improvement from admission to the time of liver biopsy. At follow-up liver function tests were generally better in patients who had stopped drinking alcohol compared to those who continued to do so. The 5-year survival rate was 82% for females without cirrhosis, and 45% for those with cirrhosis (p less than 0.03). Considering the sex-related differences in alcohol abuse in the general population we found no evidence of increased susceptibility to the hepatotoxic effect of alcohol in females.  相似文献   
988.
In a prospective, double-blind, randomized multicenter trial the efficacy and safety of low molecular weight heparin and unfractionated heparin were compared for the prevention of postoperative deep vein thrombosis in patients undergoing abdominal surgery. Six hundred and seventy-three patients were randomly allocated to the two prophylaxis groups; 20 of these, however, did not undergo surgery and did not receive any prophylaxis. Of the remaining 653 patients 323 received one subcutaneous injection of 3,000 anti-Xa units of low molecular weight heparin and 330 received subcutaneously 5,000 U heparin three times a day. Treatment was initiated 2 h preoperatively and continued for 7 to 10 days. The occurrence of DVT was determined by the 125I-labelled fibrinogen uptake test and phlebography. Venous thrombosis was diagnosed in 24 of 323 patients (7.4%) treated with low molecular weight heparin and in 26 of 330 patients (7.9%) treated with low-dose heparin. DVT of proximal veins was detected in four patients of the low molecular weight heparin group and in three patients of the low-dose heparin group. During the observation period three pulmonary emboli - one fatal and two non-fatal - occurred in patients receiving prophylaxis with low-dose heparin. No pulmonary embolism was found in patients treated with low molecular weight heparin. Both prophylactic schemes were well tolerated. Intra- and postoperative blood loss, incidence of wound hematoma, frequency and volume of intra- and postoperative blood transfusion were similar in both groups with a slight advantage for the low molecular weight heparin group.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
989.
Sclerotherapy with 5% ethanolamine oleate was used to treat 102 hydroceles in 100 patients and 63 spermatoceles in 58 patients. Scrotal ultrasound examination was performed before the sclerotherapy and at each followup visit. Of the hydroceles 98% were cured completely and 68% were cured after only 1 sclerosant instillation, while 60% of the spermatoceles resolved completely and 33% partially, with 7% failures. No hydroceles recurred during an average followup of 43 months, whereas spermatocele recurred in 4 patients more than 1 year after successful treatment, with a mean followup of 46 months. Approximately half of the patients experienced pain after treatment, 3 had infection and 2 had hematoma. No changes in the structure or size of the testicles were found by ultrasound during followup. Ethanolamine oleate sclerotherapy is a safe, effective and economical form of outpatient therapy that can be recommended as primary treatment for hydroceles in adults and as an alternative to surgery for spermatoceles with 1 to 3 cysts in elderly men in whom fertility is not important.  相似文献   
990.
The occurrence of antinuclear antibodies (ANA) in an unselected population of pregnant women was studied by an indirect immunofluorescence method. Six women out of 116 were ANA-positive (5.2%), 2 of them having a moderately high titre (1:160 and 1:320) and 1 complement-fixing ANA. The antigenic specificity of ANA was anti-single-stranded DNA in 2 cases and RNAase-sensitive anti-extractable nuclear antigen in 1 case. Two of the ANA-positive women had pre-eclampsia laevis and 1 had a premature delivery. None of the infants of the ANA-positive women had symptoms of connective tissue disease. The occurrence of ANA among pregnant women was not significantly higher than among 70 non-pregnant female control subjects (7.1%).  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