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   514287篇
  免费   33280篇
  国内免费   613篇
耳鼻咽喉   6894篇
儿科学   16843篇
妇产科学   13535篇
基础医学   85060篇
口腔科学   14480篇
临床医学   44352篇
内科学   93673篇
皮肤病学   12158篇
神经病学   36197篇
特种医学   18456篇
外国民族医学   63篇
外科学   77063篇
综合类   8477篇
一般理论   118篇
预防医学   38983篇
眼科学   12138篇
药学   40542篇
中国医学   1007篇
肿瘤学   28141篇
  2018年   4936篇
  2015年   4516篇
  2014年   6074篇
  2013年   9561篇
  2012年   12889篇
  2011年   14293篇
  2010年   8310篇
  2009年   7778篇
  2008年   13708篇
  2007年   14705篇
  2006年   14948篇
  2005年   14358篇
  2004年   14049篇
  2003年   13395篇
  2002年   13275篇
  2001年   24070篇
  2000年   25081篇
  1999年   20560篇
  1998年   5426篇
  1997年   4706篇
  1996年   5043篇
  1995年   4626篇
  1994年   4318篇
  1993年   4136篇
  1992年   15730篇
  1991年   16311篇
  1990年   16425篇
  1989年   15799篇
  1988年   14580篇
  1987年   14423篇
  1986年   13599篇
  1985年   12978篇
  1984年   9628篇
  1983年   8249篇
  1982年   4560篇
  1981年   4229篇
  1979年   9419篇
  1978年   6855篇
  1977年   5774篇
  1976年   5608篇
  1975年   6400篇
  1974年   7634篇
  1973年   7132篇
  1972年   6960篇
  1971年   6685篇
  1970年   6173篇
  1969年   5889篇
  1968年   5559篇
  1967年   5012篇
  1966年   4451篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
153.
The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy.  相似文献   
154.
155.
Maya families from Guatemala migrated to the United States in record numbers from the late 1970s to the early 1990s. Births to Maya immigrant women have created a sizable number of Maya American children. The height and sitting height of 5 to 12 years children (n = 431) were measured in 1999 and 2000. Leg length was estimated and the sitting height ratio was calculated. These data were compared with a sample of Maya children living in Guatemala measured in 1998 (n = 1,347). Maya American children are currently 11.54 cm taller and 6.83 cm longer‐legged, on average, than Maya children living in Guatemala. Consequently, the Maya Americans have a significantly lower average sitting height ratio (i.e., relatively longer legs in proportion to length of the head and trunk) than do the Maya in Guatemala. These results add support to the hypothesis that both the height and body proportions of human populations are sensitive indicators of the quality of the environment for growth. Am. J. Hum. Biol. 14:753–761, 2002. © 2002 Wiley‐Liss, Inc.  相似文献   
156.
BACKGROUND: Levels of an immunoregulatory and anti-inflammatory cytokine IL-10 are reduced in asthmatic airways, potentially contributing to more intense inflammation. Triamcinolone has anti-inflammatory properties and the anti-inflammatory effects of montelukast and formoterol have been discussed. OBJECTIVE: The purpose of this study was to define the effect of treatment with triamcinolone, montelukast and formoterol on the serum level of IL-10, eosinophil blood counts, eosinophil cationic response (ECP) and clinical parameters (symptom score, FEV1 and PC20H) in children with moderate asthma. METHODS: An 8-week, placebo-controlled and randomized, double-blind trial was carried out. The subjects were 91 children with moderate atopic asthma who were allergic to dust mite. Patients were randomly allocated to receive 400 microg triamcinolone (n = 19), 5 or 10 mg (according to age) montelukast (n = 18), 24 microg formoterol (n = 18) or placebo (n = 36). RESULTS: Seventy-nine children completed the study. After treatment with triamcinolone and montelukast the level of IL-10 in blood serum significantly increased, eosinophil blood counts and ECP levels significantly decreased and all clinical parameters improved; treatment with formoterol had no effect on IL-10 level, eosinophil blood counts in serum and bronchial hyper-reactivity; ECP level significantly decreased after treatment and asthma symptoms and FEV1 improved significantly. Mean IL-10 levels in serum before and after treatment with triamcinolone were 7.23 pg/mL with 95% CI, 6.74 -7.72% and 14.24 pg/mL with 95% CI, 11.6-16.88%, respectively (P < 0.001); with montelukast they were 6.59 pg/mL with 95% CI, 6.26-7.23% and 10.94 pg/mL with 95% CI, 8.24-12.65%, respectively (P < 0.002); with formoterol they were 7.06 pg/mL with 95% CI, 6.61-7.52% and 7.04 pg/mL with 95% CI, 6.15-7.93%. We found statistically significant correlations between serum level of IL-10 and serum level of ECP after treatment with triamcinolone and montelukast. CONCLUSION: This study demonstrates that one possible way by which triamcinolone and montelukast contribute to inhibition of inflammation is by increasing IL-10 levels.  相似文献   
157.
158.
Sphincter injury after anal dilatation demonstrated by anal endosonography.   总被引:5,自引:0,他引:5  
Anal dilatation is still used in the treatment of anal fissure and haemorrhoids. Using anorectal physiology and anal endosonography we have studied 12 men presenting with faecal incontinence following anal dilatation. Resting anal pressures were low, pudendal nerve latencies were normal; 11 men had a disrupted internal anal sphincter and in ten this was extensively fragmented. Three also had defects of the external anal sphincter. These findings demonstrate for the first time the nature of the structural injury which may be caused by anal dilatation.  相似文献   
159.
160.
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