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   179425篇
  免费   10361篇
  国内免费   462篇
耳鼻咽喉   2319篇
儿科学   5706篇
妇产科学   3732篇
基础医学   24611篇
口腔科学   8324篇
临床医学   13122篇
内科学   40092篇
皮肤病学   4535篇
神经病学   15009篇
特种医学   5489篇
外国民族医学   26篇
外科学   22078篇
综合类   1417篇
现状与发展   1篇
一般理论   62篇
预防医学   18533篇
眼科学   3241篇
药学   11020篇
中国医学   769篇
肿瘤学   10162篇
  2023年   942篇
  2022年   2119篇
  2021年   3941篇
  2020年   2611篇
  2019年   3692篇
  2018年   5155篇
  2017年   3904篇
  2016年   3645篇
  2015年   4259篇
  2014年   5821篇
  2013年   7296篇
  2012年   11400篇
  2011年   11945篇
  2010年   6096篇
  2009年   5426篇
  2008年   9159篇
  2007年   9751篇
  2006年   8983篇
  2005年   9220篇
  2004年   8645篇
  2003年   7872篇
  2002年   5910篇
  2001年   5141篇
  2000年   5139篇
  1999年   4485篇
  1998年   1580篇
  1997年   1316篇
  1996年   1309篇
  1995年   1099篇
  1994年   1098篇
  1993年   996篇
  1992年   2722篇
  1991年   2625篇
  1990年   2374篇
  1989年   2381篇
  1988年   2130篇
  1987年   1973篇
  1986年   1849篇
  1985年   1772篇
  1984年   1272篇
  1983年   1031篇
  1982年   571篇
  1981年   521篇
  1980年   512篇
  1979年   939篇
  1978年   619篇
  1977年   487篇
  1975年   550篇
  1974年   549篇
  1973年   556篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
To our knowledge, only 3 patients with an extragonadal germ cell tumor of the prostate have been described in the literature until now. We here present a patient with a germ cell tumor arising in the retroperitoneum, invading the prostate, which was successfully treated by a combination of chemotherapy and nonmutilating surgery.  相似文献   
82.
83.
The laryngeal mask in failed intubation   总被引:1,自引:0,他引:1  
  相似文献   
84.
85.
86.
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   
87.
88.
BACKGROUND: The development of a pressure ulcer is of great significance to the life-long rehabilitative management of the person with a spinal cord injury, and may indeed delay and repeatedly interfere with that process. That the period preceding admission to the specialized spinal injury unit is crucial with regard to pressure ulcer development is evident in the professional literature. Both anecdotal and empirical evidence indicates that a significant number of pressure ulcers occur as a result of management provided prior to admission, and that such ulcers are more likely to occur in those patients who have undergone a transfer process from a hospital distal to the specialist unit on a hard spinal board. AIM: In consideration of this and of the fact that, in Ireland, the interhospital transfer of spinal injured patients has usually involved the employment of such spinal boards to achieve immobilization, this study sought to identify whether or not the pressure experienced by individuals at two anatomical locations was dependent on the support surface employed. METHODOLOGY: Pressure under the occiput and sacrum of three healthy volunteers immobilized on three support surfaces was measured using air-filled pressure-measuring sacks. The surfaces employed were an uncovered spinal board; a spinal board with inflatable raft devise; and a full-body vacuum splint. DISCUSSION: Marked reductions in pressure were measured when using the inflatable raft and the vacuum mattress. The results of this study will provide a basis for a larger study and, through that, the formulation of recommendations for standardized practice along a national care pathway.  相似文献   
89.
90.
OBJECTIVES: The object of this study was to investigate the diversity among streptococcal species isolated from root canals in conjunction with endodontic therapy and to characterize their production of extracellular proteins. STUDY DESIGN: Consecutive root canal samples (RCS) taken as bacteriological controls during root canal treatment of teeth with apical periodontitis were analyzed in a total of 100 clinical cases. Bacteria were isolated and classified by selective media and gas liquid chromatography. Streptococcal strains were identified by carbohydrate fermentation, hydrolysis of aesculin/arginine, and production of enzymes. Releases of extracellular proteins by streptococci and Enterococcus spp in fluid culture media were examined with SDS-PAGE and 2-dimension gel electrophoresis (2 DE). Extracellular proteins produced were quantified and qualitatively analyzed. Specific proteins were targeted with Western immunoblot assays. Comparisons were made with type strains. RESULTS: Of a total of 241 bacterial strains recovered in the first samples submitted, Streptococcus gordonii, S anginosus, and S oralis were the most frequently isolated streptococci. In 49 of 89 resubmitted samples showing bacterial growth, S gordonii and S oralis still predominated among streptococci. Other common bacterial isolates were Enterococcus spp, Lactobacillus paracasei, and Olsenella uli. Quantitative and qualitative differences in extracellular protein production were observed among clinical isolates and laboratory streptococcal strains. In similar conditions for growth, S intermedius, S anginosus, S oralis, and S gordonii were strong producers of extracellular proteins (>3.0 microg/mL), while Enterococcus spp and S mutans were weak. Whole cell protein extracts showed a different profile from that of extracellular proteins. The chaperone protein DnaK was recognized to be produced extracellularly by S gordonii, S oralis, S anginosus, and S parasanguis. CONCLUSIONS: Being strong producers of extracellular proteins and by virtue of common presence in teeth undergoing endodontic therapy, S gordonii, S anginosus, and S oralis may be of pathogenic significance in posttreatment apical periodontitis.  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