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   13284篇
  免费   893篇
  国内免费   47篇
耳鼻咽喉   109篇
儿科学   555篇
妇产科学   307篇
基础医学   1699篇
口腔科学   358篇
临床医学   1451篇
内科学   2426篇
皮肤病学   186篇
神经病学   1097篇
特种医学   408篇
外国民族医学   3篇
外科学   1479篇
综合类   121篇
一般理论   13篇
预防医学   1784篇
眼科学   379篇
药学   904篇
中国医学   22篇
肿瘤学   923篇
  2023年   99篇
  2022年   184篇
  2021年   400篇
  2020年   217篇
  2019年   360篇
  2018年   362篇
  2017年   292篇
  2016年   268篇
  2015年   320篇
  2014年   438篇
  2013年   573篇
  2012年   897篇
  2011年   899篇
  2010年   419篇
  2009年   402篇
  2008年   702篇
  2007年   746篇
  2006年   762篇
  2005年   745篇
  2004年   694篇
  2003年   608篇
  2002年   538篇
  2001年   320篇
  2000年   292篇
  1999年   246篇
  1998年   118篇
  1997年   92篇
  1996年   89篇
  1995年   68篇
  1994年   48篇
  1992年   159篇
  1991年   126篇
  1990年   127篇
  1989年   140篇
  1988年   133篇
  1987年   109篇
  1986年   113篇
  1985年   96篇
  1984年   86篇
  1983年   58篇
  1982年   39篇
  1979年   66篇
  1978年   61篇
  1977年   59篇
  1976年   46篇
  1975年   48篇
  1974年   49篇
  1973年   59篇
  1972年   55篇
  1970年   50篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Microsatellite replication errors (RERs), consisting in random tumour-associated allele contractions or expansions, represent a frequent genetic alteration in gastric cancer and appear to be associated with important clinicopathologic parameters. To verify the role of microsatellite instability in the initial phases of gastric carcinogenesis, we analysed the status of II microsatellites in paired microdissected samples of tumour and unaffected mucosa from 30 cases of early gastric carcinoma. Fifteen tumours (50%) demonstrated RERs: these included 7 cases with RERs at one locus and 8 cases with RERs at 2 or more loci. Cases with 2 or more RERs were more frequent among intramucosal tumours, compared to tumours with submucosal spread (43% vs. 12%) and among tumours staged T1NOMx, compared to tumours staged T1N1Mx (35% vs. 0%). RER-positive microsatellite typings were statistically more frequent among tumours with intramucosal extension, lower stage (T1NOMx) and excavated growth pattern (macroscopic type III), compared to tumours with submucosal extension, higher stage (T1N1Mx) and elevated, flat or depressed growth patterns (macroscopic types IIa-IIb-IIc respectively). The above findings indicate that microsatellite instability occurs early in the progression of sporadic gastric cancer and tends to be associated with good prognostic indicators.  相似文献   
62.
63.
The authors describe the growth from 1987 through 1996 of the Occupational Pesticide Poisoning Surveillance Program at the Texas Department of Health. The program was initially based on a Sentinel Event Notification System for Occupational Risks (SENSOR) model, using sentinel providers to report cases, supplementing the passive reporting by physicians that was required by law. The model was evaluated after five years, and significant changes were implemented to improve case ascertainment. Current active surveillance methods emphasize collaboration with a number of agencies and organizations for identification of cases and follow-up. The number of confirmed occupational cases increased from 9 workers in 1987 to 99 workers in 1996. The evolution from a passive system to an active surveillance program expanded the number of reported cases and strengthened inter-agency collaborations.  相似文献   
64.
65.
66.
BACKGROUND: The electrically stimulated gracilis neoanal sphincter was initially developed to treat refractory incontinence. Good early results were reported from the two centres that pioneered the technique. The aim of this study was to assess the operation in a prospective multicentre setting. METHODS: The procedure was performed on 64 patients from seven centres worldwide and was performed in stages. All patients were evaluated clinically and manometrically before and after operation. RESULTS: There was a high incidence of infective and hardware-related complications. At a median of 10 months following closure of the defunctioning stoma 56 per cent had experienced a good functional result. The major functional problems comprised evacuatory difficulties experienced by 25 per cent. CONCLUSION: The technique is effective in treating otherwise refractory incontinence. It is, however, a complex procedure and the morbidity rate may be high, particularly during the learning curve, factors that necessitate careful patient selection. Presented to the Association of Surgeons of Great Britain and Ireland in Bournemouth, UK, April 1997 and the European Council of Coloproctology in Edinburgh, UK, June 1997; and published in abstract form as Br J Surg 1997; 88(Suppl): 39 and Int J Colorectal Dis 1997; 12: 144  相似文献   
67.
68.
69.
Regeneration of severed rat tibial nerves was functionally and morphologically compared with repair following the use of 3 anastomosis techniques: collagen guide tubes, fibrin glue and conventional microsurgical sutures. In addition, one tibial nerve was crushed in some rats. At ten weekly intervals, functional recovery, assessed by sciatic nerve stimulated evoked contraction of the flexor digitorum muscle, was quicker and more complete following nerve crush than following the anastomosis techniques which were not different from each other. Ten weeks following the surgery, the retrograde transport morphological technique indicated that the anastomosis techniques were not different from each other. The number of labeled tibial motoneurons (tube and suture groups) was significantly less than the crush group, but the glue group was intermediate. Thus, although having less extensive recovery following crush, the quicker and easier techniques of nerve repair, i.e., collagen tubes or fibrin glue, produced comparable anatomical and functional recovery as the more time-consuming, technically demanding microsurgical repair with fine sutures.  相似文献   
70.
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