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   352747篇
  免费   286376篇
  国内免费   42534篇
耳鼻咽喉   3665篇
儿科学   5935篇
妇产科学   3020篇
基础医学   95651篇
口腔科学   4297篇
临床医学   71630篇
内科学   103625篇
皮肤病学   5845篇
神经病学   25104篇
特种医学   12870篇
外国民族医学   15篇
外科学   50970篇
综合类   80057篇
现状与发展   44篇
一般理论   7篇
预防医学   54169篇
眼科学   19915篇
药学   70108篇
  189篇
中国医学   54179篇
肿瘤学   20362篇
  2022年   6815篇
  2021年   7962篇
  2020年   9765篇
  2019年   15180篇
  2018年   15914篇
  2017年   17077篇
  2016年   15052篇
  2015年   16857篇
  2014年   17913篇
  2013年   18983篇
  2012年   21788篇
  2011年   23865篇
  2010年   25527篇
  2009年   32336篇
  2008年   20167篇
  2007年   16559篇
  2006年   15317篇
  2005年   13985篇
  2004年   14232篇
  2003年   13169篇
  2002年   12592篇
  2001年   14108篇
  2000年   9007篇
  1999年   13210篇
  1998年   14084篇
  1997年   13987篇
  1996年   14931篇
  1995年   15155篇
  1994年   14879篇
  1993年   13578篇
  1992年   12832篇
  1991年   12215篇
  1990年   11173篇
  1989年   11012篇
  1988年   10554篇
  1987年   9898篇
  1986年   9429篇
  1985年   8494篇
  1984年   6552篇
  1983年   6566篇
  1982年   7613篇
  1981年   7151篇
  1980年   6812篇
  1979年   6650篇
  1978年   5823篇
  1977年   6131篇
  1976年   5750篇
  1975年   5483篇
  1974年   5040篇
  1973年   4760篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
A retrospective analysis was conducted to determine the effects of metformin on glycosylated hemoglobin (HbA1c), body weight, and adverse events in an African-American population. Thirty-six patients who were receiving combination therapy with metformin and either a sulfonylurea or insulin were identified from a hospital pharmacy database. Nineteen patients met the criteria for efficacy analysis. The combination of metformin with either a sulfonylurea or insulin resulted in a decrease of the average HbA1c from a baseline of 10.07% to 7.92% (delta = 2.15%). The effect of combination therapy on weight was variable; however, twice as many patients lost weight compared with those who gained weight. Metformin appeared to be well-tolerated, with gastrointestinal symptoms being the most commonly reported adverse events.  相似文献   
993.
994.
本文就加热及同时增加细胞内氧自由基水平对恶性胶质瘤细胞存活、增殖和细胞间隙连结通讯的影响做初步观察。用M.T.T法测定胶质瘤细胞存活率;用Ki-67抗增殖细胞核抗原单克隆抗体,通过免疫组织化学ABC染色分析胶质瘤细胞的增殖活性;用划痕染料示踪技术观察胶质瘤细胞的细胞间隙连结通讯。结果表明,H2O2和3AT能增强加热对胶质瘤细胞存活与增殖的抑制作用,促进胶质瘤细胞间隙连结通讯的改善,存在着明显的剂量和时间效应。实验结果提示,通过内外源性增加胶质瘤细胞内的氧自由基水平,将有助于强化加热治疗胶质瘤效果,并可以减少加热的剂且,降低副作用。  相似文献   
995.
Seventy-two patients of chronic obstructive pulmonary disease (COPD) of Qi deficiency syndrome with abnormal immune indices were treated with Yiqi Mianyi Granule (YQMYG) and the efficacy was compared with that of 30 cases treated with Zhenqi fuzheng Granule (ZQFZG) for control. Results showed that the markedly effective rate of symptomatic improvement of Qi deficiency in YQMYG group was 65.3%, the total effective rate 93.1%. 88.6% of the immune indices lower than normal were corrected and 43. 7% of them were normalized, while for indices that were higher than normal the rate were 78.2% and 52.9% respectively. These results suggested that YQMYG could improve symptom of Qi Deficiency markedly, strengthen cellular immunity and regulate immune dysfunction. Its therapeutic efficacy was obviously superior to ZQFZG (P<0.Q5).  相似文献   
996.
During the last decade, kala-azar, which used to be a sporadic disease, became endemic in parts of East-Azerbaijan province in north-west Iran. Many of the 1051 cases observed between 1985 and 1990 were in the district of Meshkin-Shahr (800 cases). The diagnosis was based on symptoms and signs of the disease plus a positive serological test (indirect immunofluorescence assay or direct agglutination test) and, in some cases, the finding of parasites in bone marrow smears. About 90% of the cases were children under 5 years of age. The disease incidence in 1990 was almost ten times that in 1985. New cases are diagnosed throughout the year, but mostly from January till April. Cases were treated with meglumine antimoniate with very satisfactory results; deaths were few among the treated children.  相似文献   
997.
Respiratory muscle function in cystic fibrosis.   总被引:1,自引:0,他引:1       下载免费PDF全文
A Mier  A Redington  C Brophy  M Hodson    M Green 《Thorax》1990,45(10):750-752
Maximal static expiratory and inspiratory mouth pressures (PEmax and PImax) and quadriceps femoris muscle strength were measured in 25 patients aged 16-28 years with cystic fibrosis (mean FEV1 46% predicted). Mean (SD) PEmax was 64% (18%) predicted (below 75% predicted in 16 of the 25 patients), and PImax was 64% (24%) predicted (below 75% predicted in 14 patients). Quadriceps muscle strength was 68% (20%) predicted (below 75% predicted in 17 patients). The relatively small reduction in respiratory muscle strength in these patients was unlikely to have contributed appreciably to their respiratory problems.  相似文献   
998.
The present work tries to establish the antioxidant capacity of the peripheral nervous tissue of the rat, in terms of the enzymatic activities present in this tissue that either prevent the formation of activated species as the semiquinone radical (DT-diaphorase), protect against activated oxygen species (superoxide dismutase, glutathione peroxidase), conjugate natural toxic products or xenobiotics (glutathione S-transferases, especially the activity conjugating 4-hydroxy-nonenal), or complete the glutathione system metabolism (glutathione disulfide reductase, γ-glutamyl transpeptidase). All the activities studied are lower in this tissue than they are in liver, except for γ-glutamyl transpeptidase. The relevance of the results obtained and its possible relationship with different neuropathies is discussed. It is concluded that the peripheral nervous tissue is by far less protected than the liver against oxidative damage.  相似文献   
999.
Using a direct isolation method Listeria spp. were detected in 101 (47.4%) of 213 houses investigated. L. monocytogenes was present in 45 houses (21.1%). Listeria spp. occurred at all sampling sites. Dish-cloths (37%) and surface samples round the drain in the bathroom (27.2%) were most frequently contaminated. Highest numbers (c. 10(4) c.f.u./object) were found in dish-cloths and washing-up brushes. Lower levels (up to 10(3) c.f.u./object) were obtained from kitchen sinks, refrigerator vegetable compartment samples and tooth brushes. In total, 132 isolations of Listeria spp. were made from 871 samples. L. innocua (53%) and L. monocytogenes (41%) were the predominant species in the positive samples. Other Listeria spp. were found in only 6% of the positive samples.  相似文献   
1000.
OBJECTIVES--To determine HLA-DR4 and DR1 allele frequencies in a series of patients with newly diagnosed early inflammatory arthritis. METHODS--HLA-DR1 and DR4 frequencies were determined by oligonucleotide typing of 208 patients classified as having either rheumatoid arthritis (RA) or undifferentiated inflammatory polyarthritis. RESULTS--The frequency of occurrence of DR4 in these patients with RA did not differ significantly from that in controls in the United Kingdom (42 v 37%). HLA-DR1 was increased in the group with inflammatory polyarthritis (25 v 18%). CONCLUSIONS--The frequency of DR4 is not increased in newly diagnosed community based patients with RA. This supports the hypothesis that DR4 is less important as a marker for susceptibility to RA than it is for disease persistence or severity.  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