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   36015篇
  免费   1942篇
  国内免费   113篇
耳鼻咽喉   438篇
儿科学   2140篇
妇产科学   704篇
基础医学   4593篇
口腔科学   812篇
临床医学   2539篇
内科学   7329篇
皮肤病学   838篇
神经病学   1901篇
特种医学   814篇
外科学   4977篇
综合类   1326篇
一般理论   15篇
预防医学   2110篇
眼科学   1544篇
药学   3507篇
中国医学   274篇
肿瘤学   2209篇
  2023年   236篇
  2022年   668篇
  2021年   1162篇
  2020年   641篇
  2019年   857篇
  2018年   1050篇
  2017年   726篇
  2016年   958篇
  2015年   993篇
  2014年   1355篇
  2013年   1758篇
  2012年   2406篇
  2011年   2428篇
  2010年   1382篇
  2009年   1234篇
  2008年   1770篇
  2007年   1738篇
  2006年   1759篇
  2005年   1382篇
  2004年   1386篇
  2003年   1176篇
  2002年   1003篇
  2001年   825篇
  2000年   869篇
  1999年   734篇
  1998年   319篇
  1997年   217篇
  1996年   233篇
  1995年   222篇
  1994年   178篇
  1993年   160篇
  1992年   501篇
  1991年   405篇
  1990年   431篇
  1989年   401篇
  1988年   357篇
  1987年   359篇
  1986年   348篇
  1985年   326篇
  1984年   263篇
  1983年   224篇
  1982年   141篇
  1979年   230篇
  1978年   149篇
  1977年   180篇
  1975年   171篇
  1974年   182篇
  1973年   182篇
  1972年   173篇
  1971年   161篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Aminophylline, a bronchodilator, was considered a suitable drug for targeting to the lung to treat emphysema. Factorial concept was utilized to optimize the size and drug loading of microspheres suitable for targeting. Aminophylline-loaded albumin microspheres were prepared by heat denaturation adjusting the manufacturing variables, namely albumin concentration, drug concentration, water-oil phase ratio and stirring rate at low and high levels. For two levels of the four variables the experimentation was performed in 16 batches. A good yield of well-defined microspheres of the size range, 2-30 microns, were obtained from all the batches. The drug loading was found maximum (36.33 per cent) in batch XV of microspheres prepared with low albumin concentration, high drug concentration, low water-oil phase ratio and low stirring rate. The least number (13 per cent) of microspheres of batch XV were below 7 microns and the remaining 87 per cent were above this size. Considering the payload and size, microspheres of batch XV were found suitable for targeting to the lung.  相似文献   
83.
84.
A case of papillary adenoma of type 2 pneumocytes is reported. A 57-year-old man had an unusual coin lesion in the periphery of the right lung without any symptoms. When detected in a mass survey examination, it was approximately 1.5 cm in diameter, well circumscribed, and located in S4, involving the sixth-order bronchus of B4. Light-microscopic examination revealed cuboidal tumor cells arranged in a papillary pattern. Ultrastructurally, the cells had characteristic osmiophilic lamellar bodies. By immunoperoxidase staining, the tumor cells were shown to have intracytoplasmic surfactant apoproteins. The postoperative course was uneventful, and there is no evidence of disease 8 years later.  相似文献   
85.
H Singh  P K Soni  P J Gill  L Kaur 《Indian pediatrics》1991,28(12):1483-1487
The relationship between stressful family life events and somatic complaints in 477 school children was studied. There was a significant association between life events and somatic complaints, with a general trend for somatic complaints to increase in almost direct proportion to the number of family life events. Overall occurrence of these nonspecific symptoms was more in girls. The somatic complaints were significantly more in children from nuclear families and of illiterate or poorly educated mothers. No significant association was observed between somatic complaints and number of children in the family or socio-economic status. Assessment of psychodevelopmental tasks and family environment during routine check up of children by the school health teams and their appropriate training in this field should be stressed upon.  相似文献   
86.
Earlobe reconstruction using a Limberg flap in six ears.   总被引:2,自引:0,他引:2  
Many methods of earlobe reconstruction using one or two stages have been described. These have used (i) the superimposition of two flaps, (ii) a single flap lined with a skin graft or (iii) doubled-over single or bilobed flaps. We present a new method of earlobe reconstruction using a doubled-over Limberg flap, which we have used in six ears. This produces a good-looking earlobe, which needs defatting after 3-4 months and suffered minimal necrosis at the tip of the folded flap in three cases. There was no earlobe shrinkage on long-term follow-up.  相似文献   
87.
We report a case of eosinophilic cystitis that was responsive to prednisone but that recurred when the drug was withdrawn. The cause of eosinophilic cystitis remains an enigma but it probably represents a form of allergy. Investigation of etiology and therapeutic options are discussed.  相似文献   
88.
Our data suggest that DOX resistance in P388/R-84 cells may result, at least in part, from reduced free radical formation by both suppression of flavin reductase(s) and overexpression of certain antioxidant enzymes such as GSH peroxidase and catalase. In addition, our results, in conjunction with other studies, indicate that flavin reductase(s) and antioxidant enzymes are differentially altered in cancer cells with acquired or de novo resistance to DOX. Further studies are needed, however, to elucidate the mechanism(s) by which the gene expression of these enzymes is regulated in drug-sensitive and -resistant cells.  相似文献   
89.
90.
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