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   97354篇
  免费   45569篇
  国内免费   115篇
耳鼻咽喉   1896篇
儿科学   5002篇
妇产科学   1175篇
基础医学   18165篇
口腔科学   5654篇
临床医学   14221篇
内科学   28376篇
皮肤病学   7962篇
神经病学   15097篇
特种医学   3115篇
外国民族医学   6篇
外科学   17263篇
综合类   286篇
一般理论   30篇
预防医学   6279篇
眼科学   1768篇
药学   7084篇
中国医学   1076篇
肿瘤学   8583篇
  2023年   185篇
  2022年   479篇
  2021年   2096篇
  2020年   5461篇
  2019年   11438篇
  2018年   10920篇
  2017年   11955篇
  2016年   12652篇
  2015年   12431篇
  2014年   12696篇
  2013年   13527篇
  2012年   5923篇
  2011年   5990篇
  2010年   9981篇
  2009年   6316篇
  2008年   3455篇
  2007年   2397篇
  2006年   2366篇
  2005年   1946篇
  2004年   1893篇
  2003年   1671篇
  2002年   1670篇
  2001年   1159篇
  2000年   1095篇
  1999年   580篇
  1998年   238篇
  1997年   183篇
  1996年   169篇
  1995年   145篇
  1994年   126篇
  1993年   116篇
  1992年   130篇
  1991年   107篇
  1990年   94篇
  1989年   116篇
  1988年   84篇
  1987年   72篇
  1986年   64篇
  1985年   65篇
  1984年   132篇
  1983年   111篇
  1982年   84篇
  1981年   68篇
  1980年   75篇
  1979年   64篇
  1978年   73篇
  1977年   59篇
  1976年   55篇
  1975年   59篇
  1974年   38篇
排序方式: 共有10000条查询结果,搜索用时 288 毫秒
991.
992.
993.
Pfeiffer syndrome is a rare fibroblast growth factor receptor‐related craniosynostosis with variable clinical presentations. We describe new dental findings of hypodontia, microdontia, dilacerations, and radicular dentin dysplasia in a 19‐year‐old girl, and discuss the oral health management.  相似文献   
994.
995.
996.
997.
Temporomandibular disorders (TMD) are defined as clinical conditions that involve the masticatory muscles, temporomandibular joint (TMJ) or both. The aim of this study was to evaluate serum 17β‐oestradiol and progesterone levels in menstruating women affected by internal derangement of the TMJ. A total of 142 women (mean age 30·2 ± 6·7) who referred to medical diagnostic laboratory of Iranian Academic Centre for Education, Culture and Research (ACECR), Mashhad Branch, were enrolled during 2007 and 2008. Forty‐seven individuals had disc displacement with reduction (Group IIa) according to Research Diagnostic Criteria (RDC)/TMD Axis I diagnosis. Radioimmunoassay was used for the detection of serum 17β‐oestradiol and progesterone levels in all 142 subjects. The mean progesterone level was significantly higher in control group (11·6 ± 10·4 ng mL?1) compared to women with TMD (8·4 ± 6·8 ng mL?1, P = 0·03). No significant difference was found in two groups regarding 17β‐oestradiol level. Lower progesterone level in women with TMD can suggest the more important role of this hormone in the development of the disorder.  相似文献   
998.
999.
This paper examines the extent to which food intake in malnourished populations is affected by increasing the availability of the dietary staples. Free amounts of corn and beans were supplied to 47 families in a rural Guatemalan community during eight weeks. Relative to a six‐week baseline period, adults increased their intakes by about 400 kcal (1.68 MJ) and 15 gof protein per day. The average changes for pre‐school children were 198 kcl (0.83 MJ) and 5.8 g of protein per day. The findings suggest that it is possible for adults to satisfy their energy and protein needs by consuming more corn and beans. In children, bulk may be a limiting factor and it may be necessary to resort to additional measures, such as increasing the energy density of the diet, to satisfy needs.  相似文献   
1000.
BackgroundIn patients presenting with an acute coronary syndrome, left over right coronary dominance appears to be independently associated with increased long-term mortality. This could lead to decreasing numbers of patients with a left dominant coronary artery system in older age groups.MethodsWe assessed the type of coronary dominance in different age groups in postmortem angiograms that were routinely performed at autopsy between 1993 and 2007. Coronary dominance was determined by identifying the origin of the posterior descending artery and posterolateral branches on postmortem angiography. Age, gender, and cause of death were recorded from the autopsy database. The prevalence of left dominant, right dominant, and codominant systems was determined in three increasing age categories, with cutoffs based on tertiles.ResultsA total 1620 coronary angiograms were assessed; 167 were excluded because it was not possible to determine coronary dominance. The median age of all patients was 71 years; 56% were male. Of all deaths, 40% were classified as cardiac. Regarding coronary dominance, 81.2% was right, 9.1% was left, and 9.7% was codominant. Overall, a decrease in prevalence of left and codominant coronary systems was observed with increasing age in the three age cohorts (≤63years, 64–75 years, and ≥76 years) (P=.001 for overall comparison).ConclusionsIn this large autopsy cohort, the prevalence of a left dominant or codominant coronary system decreased with increasing age. These findings could relate to a slightly higher risk of mortality in case of left versus right coronary artery occlusion.  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