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   112716篇
  免费   7465篇
  国内免费   535篇
耳鼻咽喉   1416篇
儿科学   2689篇
妇产科学   1571篇
基础医学   14430篇
口腔科学   2889篇
临床医学   10937篇
内科学   24344篇
皮肤病学   1846篇
神经病学   10960篇
特种医学   5119篇
外国民族医学   2篇
外科学   18361篇
综合类   940篇
一般理论   198篇
预防医学   7992篇
眼科学   2151篇
药学   6617篇
中国医学   153篇
肿瘤学   8101篇
  2023年   903篇
  2022年   1570篇
  2021年   3470篇
  2020年   1939篇
  2019年   2964篇
  2018年   3533篇
  2017年   2528篇
  2016年   2740篇
  2015年   3101篇
  2014年   4304篇
  2013年   5517篇
  2012年   8296篇
  2011年   8421篇
  2010年   4703篇
  2009年   4081篇
  2008年   7065篇
  2007年   6913篇
  2006年   6644篇
  2005年   6558篇
  2004年   5903篇
  2003年   5446篇
  2002年   4968篇
  2001年   1246篇
  2000年   1071篇
  1999年   1159篇
  1998年   1074篇
  1997年   838篇
  1996年   690篇
  1995年   715篇
  1994年   577篇
  1993年   567篇
  1992年   696篇
  1991年   682篇
  1990年   597篇
  1989年   571篇
  1988年   556篇
  1987年   491篇
  1986年   539篇
  1985年   541篇
  1984年   553篇
  1983年   490篇
  1982年   460篇
  1981年   458篇
  1980年   377篇
  1979年   389篇
  1978年   346篇
  1977年   328篇
  1975年   281篇
  1974年   259篇
  1973年   244篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
Treatment of traumatically intruded teeth is based largely on empirical clinical experience rather than on scientific data. The aim of this qualitative meta-analysis was to provide an evidence base to evaluate the orthodontic repositioning approach. In a MEDLINE search of the literature in English, 14 reported patients involving 22 teeth were found to have been treated by this modality. Additionally, 3 new patients, involving 9 intruded teeth and presented herein, were combined to form a total study sample of 17 subjects (7 girls, 10 boys, aged 8.9 +/- 1.2 years). Orthodontic extrusive forces were applied in the immediate posttrauma period (up to 3 months), with a variety of orthodontic appliances. Repositioning was achieved for 90.3% of the affected teeth but failed in 9.7% because of inflammatory resorption (2 teeth) or a misdiagnosis of root fracture (1 tooth). Early complications included loss of pulp vitality and external root resorption. All intruded teeth with closed root apices lost their vitality regardless of the degree of intrusion, whereas among those with incomplete apices, 45.5% that had been moderately intruded remained vital. External resorption was encountered in 54.8% of the teeth. Loss of marginal bone support was rarely encountered. Late complications included inflammatory root resorption in teeth with closed apices, in which endodontic treatment was not initially performed, and obliteration of the pulp tissue in teeth that remained vital. The results show that this method is superior to other treatment alternatives.  相似文献   
24.
Nurses must frequently make ethical decisions. These decisions require judgment, knowledge, and skills. This article will provide one framework for ethical decision making and provide several examples of the process.  相似文献   
25.
26.
27.
28.
Mielke  H.  Daniel  W.  Deicher  H.  Drommer  W.  Fischer  M.  Fritsch  R.  M&#;ller-Vahl  H.  Sybrecht  G. W. 《Clinical rheumatology》1987,6(2):26-34
Clinical Rheumatology - Rheumatoid arthritis (RA) as a systemic disease can attack many other organs in addition to the joints. A variety of pathological lesions of the blood vessels are...  相似文献   
29.
A cytomorphometric analysis of superficial vaginal cells inwomen in three groups of different types of hormonal concentrationwas made. There were 15 women in each group. Group I was studiedduring a natural cycle, group II under oral contraceptive therapyand group III during an in-vitro fertilization (IVF) stimulationprotocol. Morphometric parameters were measured on an imageanalyser. The area, perimeter and several form factors weremeasured separately for nuclei and cytoplasm. The nucleus:cytoplasmicratio was also determined. The cytoplasmic area was significantlyreduced in group II and was associated with a statisticallysignificant reduction of the nuclear area. The nucleus:cytoplasmicratio appeared significantly increased in group II and reducedin group III. Low oestradiol impregnation obtained with an oralminidosed contraceptive interfered with vaginal cell maturation.High oestradiol concentrations obtained during IVF protocolsinduced marked nuclear pycnosis but did not induce supra-physiologicalcell enlargement. Maximal cell size is genetically regulatedaccording to Driesch's law of volume invariance and hormonalover-stimulation has no effect on cell size. The nucleus:cytoplasmicratio appears to be a powerful parameter reflecting the oppositeeffects of hormones on cell compartments.  相似文献   
30.
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