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   7025篇
  免费   543篇
  国内免费   30篇
耳鼻咽喉   94篇
儿科学   151篇
妇产科学   164篇
基础医学   1229篇
口腔科学   112篇
临床医学   587篇
内科学   1529篇
皮肤病学   219篇
神经病学   875篇
特种医学   270篇
外科学   744篇
综合类   35篇
一般理论   6篇
预防医学   537篇
眼科学   145篇
药学   434篇
中国医学   8篇
肿瘤学   459篇
  2023年   72篇
  2022年   101篇
  2021年   229篇
  2020年   169篇
  2019年   219篇
  2018年   240篇
  2017年   193篇
  2016年   228篇
  2015年   244篇
  2014年   255篇
  2013年   348篇
  2012年   539篇
  2011年   543篇
  2010年   331篇
  2009年   289篇
  2008年   469篇
  2007年   378篇
  2006年   410篇
  2005年   345篇
  2004年   302篇
  2003年   260篇
  2002年   203篇
  2001年   98篇
  2000年   81篇
  1999年   95篇
  1998年   69篇
  1997年   52篇
  1996年   35篇
  1995年   33篇
  1994年   23篇
  1993年   27篇
  1992年   47篇
  1991年   45篇
  1990年   46篇
  1989年   66篇
  1988年   39篇
  1987年   40篇
  1986年   35篇
  1985年   29篇
  1984年   41篇
  1983年   20篇
  1982年   14篇
  1980年   17篇
  1979年   32篇
  1978年   14篇
  1977年   17篇
  1975年   18篇
  1974年   20篇
  1973年   15篇
  1969年   17篇
排序方式: 共有7598条查询结果,搜索用时 15 毫秒
1.
BACKGROUND The adenoma detection rate(ADR) is inversely associated with the incidence of interval colorectal cancer and serves as a benchmark quality criterion during screening colonoscopy. However, adenoma miss rates reach up to 26% and studies have shown that a second inspection of the right colon in retroflected view(RFV) can increase ADR.AIM To assess whether inspection of the whole colon in RFV compared to standard forward view(SFV) can increase ADR.METHODS Patients presenting for screening or surveillance colonoscopy were invited to participate in this randomized controlled trial and randomized into two arms. In RFV arm colonoscopy was initially performed with SFV, followed by a second inspection of the whole colon in RFV. In the SFV arm first withdrawal was performed with SFV, followed by a second inspection of the whole colon again with SFV. Number, size and morphology of polyps found during first and second inspection in each colonic segment were recorded and all polyps were removed and sent for histopathology in separate containers.RESULTS Two hundred and five patients were randomly assigned to the RFV(n = 101) and SFV(n = 104) arm. In the RFV arm, both polyp detection rate(PDR) and ADR were increased under second inspection in RFV(PDR 1~(st) SFV: 39.8%, PDR 2~(nd)RFV: 46.6%; ADR 1~(st) SFV: 35.2%, ADR 2~(nd) RFV: 42%). Likewise, in the SFV arm,PDR and ADR were increased under second inspection(PDR 1~(st) SFV: 37.5%, PDR 2~(nd) SFV: 46.6%; ADR 1~(st) SFV: 34.1%, ADR 2~(nd)SFV: 44.3%) with no significant differences in ADR and PDR between the SFV and RFV arm. Mean number of adenomas per patient(APP) was increased in the RFV and SFV(APP RFV arm: 1~(st) SFV: 1.71; 2~(nd) RFV: 2.38; APP SFV arm: 1~(st) SFV: 1.83, 2~(nd)SFV:2.2). The majority of adenomas additionally found during second inspection in RFV or in SFV were located in the transverse and left-sided colon and were 5 mm in size.CONCLUSION Second inspection of the whole colon leads to increased adenoma detection with no differences between SFV and RFV. Hence, increased detection is most likely a feature of the second inspection itself but not of the inspection mode.  相似文献   
2.
Tauchunfälle     
Notfall + Rettungsmedizin - Tauchunfälle sind vergleichsweise selten und stellen (Erst‑)Helfer vor besondere Herausforderungen. Sie müssen schnell und kompetent behandelt werden, da...  相似文献   
3.
Die Gynäkologie - Frauen im Erwachsenenalter mit einem angeborenen Herzfehler (EMAH) werden in Zukunft aufgrund des medizinischen Fortschritts eine immer größere Patientinnengruppe...  相似文献   
4.
BACKGROUND: The problems associated with rectal surgery are frequently discussed with no reference being made to the distance of the tumor from the anal verge. This study examined the effect of the location of the tumor on early postoperative results. PATIENTS AND METHODS: This was a multicenter study involving 75 German hospitals and 3756 patients, of whom 1463 had rectal carcinoma. On the basis of the location of the tumor (distance from the anal verge), four groups were distinguished: <4, 4-7.9, 8-11.9, and 12-16 cm. RESULTS: Resection and abdominoperineal resection rates and the incidence of postoperative complications depended on the location of the tumor. Significantly higher resection rates and fewer specific complications, and a significant reduction in overall postoperative morbidity were found with tumor locations more than 8 cm from the anal verge. The highest anastomotic leak rate was observed with anastomoses less than 7 cm from the anal verge. The logistic regression showed that the distance of the tumor from the anal verge is an independent variable for the development of an anastomotic leak. CONCLUSIONS: Early results are greatly affected by the location of the rectal carcinoma. This applies to both abdominoperineal resection rates and specific postoperative complications, such as anastomotic leak rate and operation morbidity in general.  相似文献   
5.
A novel assay for factor XIII is described that utilizes exclusively small synthetic peptides as substrates for the cross-linking reaction catalyzed by activated factor XIII (FXIIIa). The acyl donor substrate (selection peptide) is immobilized on a microplate via biotin while the acyl acceptor substrate (detection peptide) is labeled with the fluorochrome Oregon green to allow sensitive detection without the need for secondary enzyme systems for signal amplification. Starting with an amino acid sequence from the fibrin gamma-chain (GQQHHLGGAKQAGDV) as a prototype peptide, the influence of amino acid exchanges were investigated with respect to their impact on the FXIIIa-catalyzed reaction. It was found that FXIIIa readily accepts a broad range of substrate peptides, with a proline neighboring the essential lysine having the most detrimental effect. The assay appears to be valuable for the molecular characterization of factor XIII and may be used for a deeper investigation into the substrate requirements of this final enzyme of wound repair, and eventually also for the characterization of other transglutaminases.  相似文献   
6.
It obviously escaped the notion of Egeland and Brinchman thatthe protocols additionally differ with regard to the washingsteps and buffer components used in the  相似文献   
7.
8.
9.
This report describes a young high-myopic patient who developed rubeosis iridis with peripheral retinal neovascularization one year after a circular buckling operation. Subsequently, vitreous bleeding and exudation led to traction retinal detachment which was treated successfully by anterior vitrectomy and cryopexy. It is suggested that this case represents a mild form of anterior-segment ischemia, combined with peripheral retinal ischemia.  相似文献   
10.
A 31-year-old married man with normal male characteristics requested hormonal treatment to enlarge his breasts and nipples. He did not feel himself to be homosexual or transsexual but considered himself incomplete without female breasts and nipples. Petting of his nipples resulted in sexual excitement and he presumed that feminization of his breasts would improve this function. His wife supported his wish. After treatment with 0.150 mg ethinylestradiol per day for 9 months, moderate breast enlargement occurred and the nipples became the size of normal female nipples. One year afterwards he remained satisfied with his female-type breasts and in particular with the increased sexual function of his nipples. Stimulation of his nipples resulted in erection and ejaculation.  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