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   2436465篇
  免费   172131篇
  国内免费   3451篇
耳鼻咽喉   32670篇
儿科学   78885篇
妇产科学   64253篇
基础医学   357579篇
口腔科学   64508篇
临床医学   216889篇
内科学   476178篇
皮肤病学   52293篇
神经病学   193878篇
特种医学   91972篇
外国民族医学   492篇
外科学   368623篇
综合类   48201篇
现状与发展   12篇
一般理论   849篇
预防医学   189888篇
眼科学   55252篇
药学   179283篇
  11篇
中国医学   4598篇
肿瘤学   135733篇
  2021年   19369篇
  2019年   19824篇
  2018年   35670篇
  2017年   27331篇
  2016年   31164篇
  2015年   26279篇
  2014年   36838篇
  2013年   54810篇
  2012年   77980篇
  2011年   87783篇
  2010年   53589篇
  2009年   49542篇
  2008年   83134篇
  2007年   89875篇
  2006年   81340篇
  2005年   80191篇
  2004年   77237篇
  2003年   75439篇
  2002年   72113篇
  2001年   109054篇
  2000年   111953篇
  1999年   93752篇
  1998年   27296篇
  1997年   23984篇
  1996年   24292篇
  1995年   22937篇
  1994年   21134篇
  1993年   19909篇
  1992年   72170篇
  1991年   70246篇
  1990年   68554篇
  1989年   65796篇
  1988年   60415篇
  1987年   59244篇
  1986年   55338篇
  1985年   53132篇
  1984年   39397篇
  1983年   33478篇
  1982年   19969篇
  1979年   35982篇
  1978年   25711篇
  1977年   21253篇
  1976年   20401篇
  1975年   21824篇
  1974年   26179篇
  1973年   24812篇
  1972年   23206篇
  1971年   22040篇
  1970年   20277篇
  1969年   19347篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The Brief Symptom Inventory (BSI), a 53-item psychiatric symptom checklist, was administered to 57 alcoholic inpatients on days 2, 10, 18 and 26 of their 28-day stay in an alcoholism rehabilitation unit at a Veterans Administration hospital. The results of the test show a steady decline in the patients' psychiatric symptomatology from week 1 to week 4 with the most dramatic improvement evidenced between weeks 1 and 2.  相似文献   
992.
The authors have presented the results of a 14-day open randomized trial of the efficacy of 3 calcium inlet blocking agents: nifedipine, verapamil and phendilin in 61 patients with Raynaud's syndrome. In the group of patients receiving 30-80 mg of nifedipine (20) there was a significant decrease in the frequency and expression of Raynaud's syndrome attacks, a positive effect of varying degree was noted in 19 patients. The drug raised slightly the skin and muscular blood flow and skin temperature. The use of 120-360 mg of verapamil in 21 patients caused no significant inhibition of Raynaud's syndrome and rise of hemocirculation. Phendilin (150-300 mg) though being comparable with nifedipine in efficacy, often produced side-effects resulting in the drug cancellation (8 out of 20). The efficacy of the calcium inlet blocking agents, especially nifedipine, for therapy of Raynaud's syndrome was emphasized.  相似文献   
993.
The in vitro activities of beta-lactam antibiotics against Bacteroides fragilis and B. fragilis group isolates are presented. Clinical isolates from 1986 were compared with strains from 1979 to 1982. Imipenem, ticarcillin-clavulanic acid, and ceftizoxime were the most active agents. Cefotetan was equivalent to cefoxitin against B. fragilis but less active against B. fragilis group isolates. Enhancement of cefotaxime by its desacetyl metabolite was minimal.  相似文献   
994.
995.
996.
997.
998.
An endoscopic endonasal approach was performed to remove an intra-suprasellar Rathke's cleft cyst. Rathke's cleft cyst are benign lesions, rarely diagnosed because they are often asymptomatic. To the best of our knowledge, at least 475 cases of Rathke's cleft cysts have been reported. They seem to arise from remnants of Rathke's pouch, an invagination of the stomodeum. A 52-year-old woman, complaining of bilateral frontal headaches, was operated on by using an endoscopic endonasal approach, for an intra-suprasellar tumor. The pre-operative diagnosis was non-functioning pituitary adenoma. Intra-operatively a creamy-coloured viscous tissue was found. After the removal of the cyst contents and of the capsule, the suprasellar structures were seen well. The chiasmatic cistern, the chiasm, the pituitary stalk and the pituitary gland were visualized with 0 and 30 degree endoscopes. The pathological findings showed a well-differentiated cuboidal epithelium. The diagnosis was Rathke's cleft cyst. No post-operative complications were observed. The endoscopic technique was particularly suitable in this case, both for the Rathke's cleft features and for an excellent outcome. The Rathke's cleft cyst was easily removed by suction and the cyst wall was entirely removed with curettes and pituitary punches. The hypophysis was distinguished from the cyst and was preserved. The surgical manoeuvres were all done under direct visual control. The absence of nasal packing and of breathing difficulties made comfortable the post-operative outcome. Thus, the endoscopic endonasal approach can be considered the favourite technique in case of either intra- and/or suprasellar Rathke's cleft cysts.  相似文献   
999.
1000.
OBJECTIVE: Traditional assessments of the microbial flora associated with acute bacterial rhinosinusitis have relied on maxillary sinus punctures (taps) and culture. These taps are now considered the gold standard for obtaining cultures and are used as the method of identifying bacterial pathogens in antimicrobial trials. Maxillary sinus taps are limited by discomfort to the patients and technical concerns. Because of these factors, the standard of performing taps has limited antibiotic trials and microbial surveillance. Alternatives to maxillary sinus taps have been explored. STUDY DESIGN: We conducted a retrospective, systematic review of the literature from 1950 to 2000 of articles comparing culture techniques in the nose and paranasal sinuses for acute bacterial rhinosinusitis. RESULTS: Nasal cultures have poor correlation to maxillary sinus cultures, whereas there is 60% to 85% concordance between endoscopically guided middle meatal cultures and maxillary sinus cultures. These studies, however, are all limited by small sample sizes and therefore are inadequate to make any concrete recommendations regarding the relative role of endoscopically guided middle meatal cultures as a formal method of pathogen identification in acute bacterial rhinosinusitis. CONCLUSION: A formal prospective study with sufficient sample size to assess the concordance between the microbial flora of the maxillary sinus punctures and middle meatal cultures in acute rhinosinusitis is recommended.  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