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   1695325篇
  免费   123712篇
  国内免费   3781篇
耳鼻咽喉   21730篇
儿科学   55635篇
妇产科学   46152篇
基础医学   241213篇
口腔科学   48743篇
临床医学   151311篇
内科学   333527篇
皮肤病学   38653篇
神经病学   131151篇
特种医学   63873篇
外国民族医学   242篇
外科学   257256篇
综合类   38947篇
现状与发展   4篇
一般理论   531篇
预防医学   124234篇
眼科学   40211篇
药学   123605篇
  7篇
中国医学   4476篇
肿瘤学   101317篇
  2021年   12786篇
  2019年   13522篇
  2018年   19952篇
  2017年   15217篇
  2016年   16615篇
  2015年   18959篇
  2014年   26218篇
  2013年   37946篇
  2012年   52732篇
  2011年   55424篇
  2010年   32775篇
  2009年   30696篇
  2008年   51527篇
  2007年   54800篇
  2006年   55259篇
  2005年   52545篇
  2004年   50745篇
  2003年   48158篇
  2002年   46373篇
  2001年   91789篇
  2000年   93608篇
  1999年   76963篇
  1998年   19719篇
  1997年   17268篇
  1996年   17393篇
  1995年   16742篇
  1994年   15289篇
  1993年   14073篇
  1992年   57381篇
  1991年   55271篇
  1990年   52971篇
  1989年   50747篇
  1988年   46131篇
  1987年   44937篇
  1986年   42226篇
  1985年   39987篇
  1984年   29348篇
  1983年   24908篇
  1982年   13898篇
  1979年   25529篇
  1978年   17574篇
  1977年   14906篇
  1976年   13875篇
  1975年   14563篇
  1974年   17630篇
  1973年   16944篇
  1972年   15674篇
  1971年   14453篇
  1970年   13435篇
  1969年   12521篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease. Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India  相似文献   
133.
134.
We evaluated the therapeutic efficacy of miconazole (MCZ, Florid-F inj.), a new antifungal agent for parenteral use, in deep-seated fungal infections of respiratory tract system. A daily dose of 400-1,800 mg of MCZ was given intravenously for 12-38 days (mean: 23.4 days) to 7 patients: 2 patients with pulmonary aspergillosis, 1 patient with bronchial aspergillosis, 1 patient with pulmonary candidiasis and 3 patients with candidemia. One additional patient with pulmonary aspergillosis received three instillations of 20 mg of MCZ into the thoracic cavity. The clinical effects were excellent in 1, good in 4 and poor in 3 patients. The efficacy rate was 100% in 5 cases with respiratory fungal infections but 3 cases with candidemia did not respond well to the treatment. Four strains each of Aspergillus sp. and Candida sp. were identified as causative organisms. Seven of the 8 strains were eradicated by administration of MCZ. Side effects observed were irritation and heat in a leg in 1 patient, hyperlipoidemia in 2 patients and eosinophilia in 1 patient. The adverse reactions disappeared after the completion of the therapy. From the above results, we conclude that MCZ is one of the most useful antifungal agents for parenteral use as a first choice on deep-seated fungal infections in the respiratory tract.  相似文献   
135.
136.
137.
138.
The biodistribution of two recently developed tumour markers, trimethylated (CP(Me)3) and trimethoxylated (CP(OMe)3) carotenoporphyrin, was investigated by means of laser-induced fluorescence (LIF) after i.v. injection into 38 tumour-bearing (MS-2 fibrosarcoma) female Balb/c mice. At 3, 24, 48 or 96 h after administration, the carotenoporphyrin fluorescence was measured in tumoral and peritumoral tissue, as well as in the abdominal, thoracic and cranial cavities. The fluorescence was induced by a nitrogen laser-pumped dye laser, emitting light at 425 nm, and analysed by a polychromator equipped with an image-intensified CCD camera. The fluorescence was evaluated at 490, 655 and 720 nm: the second and third wavelengths represent the carotenoporphyrin (CP)-related peaks, whereas the first one is close to the peak of the tissue autofluorescence. The tumour and the liver were the two tissue types showing the strongest carotenoporphyrin-related fluorescence, whereas the cerebral cortex and muscle consistently exhibited weak substance-related fluorescence. In most tissue types, the fluorescence intensities decreased over time. A few exceptions were observed, notably the liver, in which the intensity remained remarkably constant over the time period investigated.  相似文献   
139.
Abstract Perioscan requires a plaque sample to detect the presence of enzymes capable of degrading N-benzoyl-DL-arginine-2-naphthylamide (BANA) from relatively few anaerobic periodontal pathogens. Periocheck assays the presence of neutral proteases in crevicular fluid. The aim of this study was to compare these test kits with traditional clinical methods of detecting periodontal disease and to monitor the ability of the kits to reflect the response to initial therapy. 19 patients with moderately severe chronic periodontitis were seen before and after a course of oral hygiene and root instrumentation consisting of 4 appointments. Clinical measurements and test assays were collected at 5 diseased sites and 2 healthy sites in each subject. Complete data from 125 sites were available for statistical analysis. At baseline Periocheck had a sensitivity of 88% and a specificity of 61% whereas Perioscan had a sensitivity of 99% and a specificity of 55%, when related to the clinical diagnosis. A composite clinical assessment, based on improvement or deterioration of one whole unit change of the subjective clinical indices and 2mm changes or greater in probing depth or probing attachment level, revealed 75 sites which improved following treatment, whereas 45 sites did not change and 5 sites deteriorated. The probability that the tests agreed with the clinical outcome after treatment, was calculated as 50.4% for Periocheck and 52% for Perioscan. The diagnostic kits did not reliably reflect the clinical assessment of periodontal disease in the cross sectional study, or the outcome following treatment.  相似文献   
140.
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