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   32947篇
  免费   2357篇
  国内免费   138篇
耳鼻咽喉   446篇
儿科学   788篇
妇产科学   743篇
基础医学   4274篇
口腔科学   1350篇
临床医学   2775篇
内科学   8078篇
皮肤病学   722篇
神经病学   2815篇
特种医学   967篇
外科学   5153篇
综合类   213篇
一般理论   13篇
预防医学   2266篇
眼科学   822篇
药学   1766篇
  1篇
中国医学   84篇
肿瘤学   2166篇
  2023年   205篇
  2022年   456篇
  2021年   1004篇
  2020年   587篇
  2019年   948篇
  2018年   1176篇
  2017年   746篇
  2016年   833篇
  2015年   986篇
  2014年   1299篇
  2013年   1583篇
  2012年   2527篇
  2011年   2543篇
  2010年   1444篇
  2009年   1270篇
  2008年   1997篇
  2007年   2144篇
  2006年   1904篇
  2005年   1759篇
  2004年   1510篇
  2003年   1314篇
  2002年   1195篇
  2001年   451篇
  2000年   402篇
  1999年   477篇
  1998年   291篇
  1997年   254篇
  1996年   208篇
  1995年   221篇
  1994年   201篇
  1993年   195篇
  1992年   314篇
  1991年   265篇
  1990年   220篇
  1989年   245篇
  1988年   213篇
  1987年   185篇
  1986年   199篇
  1985年   186篇
  1984年   162篇
  1983年   135篇
  1982年   108篇
  1981年   114篇
  1980年   67篇
  1979年   104篇
  1978年   87篇
  1977年   66篇
  1976年   69篇
  1975年   68篇
  1973年   76篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
The present study provides an analysis of the effects of particular patterns of teacher respose to students' entries in dialogue journals. It extended on previous research related to teacher-student instructional discourse by concentrating on written, teacher-student interactions. Second grade children who were participating in a daily dialogue journal activity were randomly subjected to two types of response patterns by their teacher. The results show that a teacher's elaborative responses to student journal entries directly lead to increase written output by students coupled with a distinct process #ophigher order#cp orientation of student entries.  相似文献   
32.
Cementoblastomas are benign lesions of the odontogenic ectomesenchyme that rarely occur related to the primary dentition, especially on the left side of the mandible. This study describes a case of a true cementoblastoma related to the left second primary mandibular molar in a 7-year-old child (the largest one seen in the left side of the mandible). Additionally, the radiographic and histologic findings of the lesion are described in details.  相似文献   
33.
Ciclesonide is an onsite-activated inhaled corticosteroid (ICS) for the treatment of asthma. This study compared the efficacy, safety and effect on quality of life (QOL) of ciclesonide 160 microg (ex-actuator; nominal dose 200 microg) vs. budesonide 400 microg (nominal dose) in children with asthma. Six hundred and twenty-one children (aged 6-11 yr) with asthma were randomized to receive ciclesonide 160 microg (ex-actuator) once daily (via hydrofluoroalkane metered-dose inhaler and AeroChamber Plus spacer) or budesonide 400 microg once daily (via Turbohaler) both given in the evening for 12 wk. The primary efficacy end-point was change in forced expiratory volume in 1 s (FEV1). Additional measurements included change in daily peak expiratory flow (PEF), change in asthma symptom score sum, change in use of rescue medication, paediatric and caregiver asthma QOL questionnaire [PAQLQ(S) and PACQLQ, respectively] scores, change in body height assessed by stadiometry, change in 24-h urinary cortisol adjusted for creatinine and adverse events. Both ciclesonide and budesonide increased FEV1, morning PEF and PAQLQ(S) and PACQLQ scores, and improved asthma symptom score sums and the need for rescue medication after 12 wk vs. baseline. The non-inferiority of ciclesonide vs. budesonide was demonstrated for the change in FEV1 (95% confidence interval: -75, 10 ml, p = 0.0009, one-sided non-inferiority, per-protocol). In addition, ciclesonide and budesonide showed similar efficacy in improving asthma symptoms, morning PEF, use of rescue medication and QOL. Ciclesonide was superior to budesonide with regard to increases in body height (p = 0.003, two-sided). The effect on the hypothalamic-pituitary-adrenal axis was significantly different in favor of ciclesonide treatment (p < 0.001, one-sided). Both ciclesonide and budesonide were well tolerated. Ciclesonide 160 microg once daily and budesonide 400 microg once daily were effective in children with asthma. In addition, in children treated with ciclesonide there was significantly less reduction in body height and suppression of 24-h urinary cortisol excretion compared with children treated with budesonide after 12 wk.  相似文献   
34.
35.
Purpose Reelin is important in the guidance of neuronal stem cells in the central nervous system during normal development. We wished to determine whether reelin is expressed in the retina and cornea after injury. Methods Mice underwent laceration of their retina as well as corneal epithelial debridement. The mice were sacrificed at 3 days, and eyes were fixed and stained for reelin expression and reelin messenger ribonucleic acid (mRNA). Results In normal eyes, reelin was expressed only at very low levels in the ganglion cell layer of the retina and the endothelial cell layer of the cornea. In injured eyes, there was marked expression in reelin immunoreactivity in the retina and cornea. Reelin gene expression was seen in the retina and cornea. Conclusions Reelin is expressed during normal retinogenesis. This study shows that reelin is also upregulated following injury to the retina and cornea. The expression of reelin following injury suggests that reelin may play an important role in regulating stem cell trafficking in neuronal and nonneuronal tissues following injury similar to its role in normal organogenesis. For consideration of publication in Graefe’s Archive for Clinical and Experimental Ophthalmology.  相似文献   
36.
37.
38.
5H-Mebendazole and some related heterocyclic methyl carbamates were synthesized and their anthelmintic activity against Caenorhabditis elegans was determined. In order to study the influence of the heteroaromatic region with regard to the carbamate moiety on biological activity, the molecular electrostatic potentials (MEP) of all structures were calculated and a structure-activity relationship (SAR) was established. The electrostatic pattern of activity includes two minima of the carbamate moiety, a third heterocyclic minimum, and a pi-electronic region.  相似文献   
39.
40.
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