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   179856篇
  免费   9082篇
  国内免费   211篇
耳鼻咽喉   2733篇
儿科学   5794篇
妇产科学   3891篇
基础医学   27662篇
口腔科学   5649篇
临床医学   15072篇
内科学   33141篇
皮肤病学   4967篇
神经病学   18886篇
特种医学   7764篇
外国民族医学   2篇
外科学   27648篇
综合类   779篇
一般理论   49篇
预防医学   9727篇
眼科学   3543篇
药学   12337篇
中国医学   258篇
肿瘤学   9247篇
  2023年   1015篇
  2022年   801篇
  2021年   1895篇
  2020年   1645篇
  2019年   2065篇
  2018年   3659篇
  2017年   3165篇
  2016年   4023篇
  2015年   3710篇
  2014年   4274篇
  2013年   7103篇
  2012年   9183篇
  2011年   10011篇
  2010年   5798篇
  2009年   4356篇
  2008年   9912篇
  2007年   10330篇
  2006年   10049篇
  2005年   9892篇
  2004年   9328篇
  2003年   9420篇
  2002年   9303篇
  2001年   6468篇
  2000年   7831篇
  1999年   4812篇
  1998年   2035篇
  1997年   1701篇
  1996年   1340篇
  1995年   1140篇
  1994年   1123篇
  1993年   1057篇
  1992年   1392篇
  1991年   1291篇
  1990年   1278篇
  1989年   1257篇
  1988年   1072篇
  1987年   1144篇
  1986年   1003篇
  1985年   1211篇
  1984年   1065篇
  1983年   927篇
  1982年   843篇
  1981年   802篇
  1980年   720篇
  1979年   844篇
  1978年   729篇
  1977年   715篇
  1976年   593篇
  1975年   658篇
  1974年   587篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

Background  

The telomeric region of mouse chromosome 12 has previously shown frequent allelic loss in murine lymphoma. The Bcl11b gene has been identified and suggested as a candidate tumor suppressor gene within this region. In this study, we aimed to elucidate whether Bcl11b is mutated in lymphomas with allelic loss, and whether the mutations we detected conferred any effect on cell proliferation and apoptosis.  相似文献   
92.
The purpose of the present study was to investigate the influence of different drugs exhibiting different solubility on the viscoelastic properties and on the skin diffusion profile of a ringing gel. In a preliminary rheology study with the placebo gel predominating elastic properties were confirmed and a temperature influence was indicated. Fluconazole, fludrocortisone-acetate, flumethasone-pivalate, flutamide and flufenamic-acid each 1% (w/w) were incorporated into the preparation and oscillatory measurements were performed at temperatures of 25, 28, 32 and 37 degrees C. In all drug containing formulations a high elastic G' value predominated the viscous G' value. The highest G' value could be obtained with the incorporated flumethasone-pivalate. Additionally in almost all cases the G' values decreased with increasing temperature compared to the placebo gel. Additionally in vitro standard diffusion experiments using Franz-type cells and porcine skin were performed. Following rank order of the cumulative drug release after 48 h was obtained: fluconazole>flufenamic-acid>flumethasone-pivalate>flutamide>fludrocortisone-acetate. Furthermore an excellent chemical stability of all incorporated drugs was confirmed over 10 weeks.  相似文献   
93.
Abstract 10 embalmed cadaver forearms and wrists were dissected to determine the anatomical course of the superficial branch of the radial nerve in the distal forearm. The superficial radial nerve bifurcated in two branches at a mean of 54,7 mm proximal to the radial styloid. From the styloid process of the radius, the mean distance to the closest dorsal branch of the superficial radial nerve was 3,5 mm and the mean distance to the closest volar branch was 9,8 mm. The mean distance between the closest branch of the superficial radial nerve and Lister?s tubercle was 16,4 mm. The crossing point between the nerve and the cephalic vein was located at a mean of 54,3 mm proximal to the styloid process. At the level of styloid process the mean distance between the closest dorsal branch of the superficial radial nerve and the first dorsal compartment was 15,2 mm and between the closest volar branch and the first dorsal compartment 4,4 mm. Detailed knowledge of anatomic characteristics of the superficial branch of the radial nerve may help prevent injury during operations and treat traumatic lesions of the nerve. Because of great variations in the course of the superficial radial nerve we could not define an absolute safe zone for surgical procedures on the distal forearm. Iatrogenic lesions of the superficial radial nerve are described complications of percutaneous procedures. Therefore open surgical approaches are recommended. Daniela Klitscher and Lars Peter Müller contributed equally to this work.  相似文献   
94.
ZusammenfassungEinleitung In unserer Klinik wird seit über 30 Jahren die operative Behandlung von Klumpfüßen über einen dorsomedialen Zugang durchgeführt. Postoperativ erfolgt zunächst eine Gipsbehandlung, dann eine konsequente Nachbehandlung mit Orthesen und Winkeleinlagen.Material und Methode Zwischen dem 1. 6. 1986 und dem 31. 12. 2000 wurden 130 primäre Klumpfußweichteiloperationen bei 86 Patienten durchgeführt. 119 (92%) Füße konnten nach durchschnittlich 4,5 Jahren klinisch-radiologisch nachuntersucht werden. Das durchschnittliche Alter bei der Operation betrug 7,6 Monate. Klassifikation nach Dimeglio und Score nach Laaveg und Ponseti dienten zur Beurteilung. Die gemessenen Winkel in den belasteten Röntgenbildern des Fußes a.p. und seitlich prä- und postoperativ wurden verglichen, Komplikationen und Rezidive dokumentiert.Ergebnisse 29 (22,3%) Füße wiesen einen Schweregrad IV nach Dimeglio, 58 (44,6%) Grad III und 43 (33,1%) Grad II auf. Ein Klumpfußrezidiv war bei 9 (7,6%) Fällen zu beobachten. Alle Winkel verbesserten sich signifikant. Bei der Nachuntersuchung wurden durchschnittlich 95,4±9,2 Punkte nach dem Score von Laaveg und Ponseti erzielt.Schlussfolgerung Der von uns verwendete dorsomediale Zugangsweg erlaubt eine ausgezeichnete Klumpfußkorrektur mit geringer Rezidiv- und Komplikationsrate.  相似文献   
95.
96.
97.
98.
Clinical practice guidelines have been proposed to significantly reduce the gap between available scientific evidence and clinical practice. Evidence-based guidelines are also being produced at an ever-increasing pace. However, guidelines do not implement themselves, and the research to support implementation does not provide straightforward answers. What works in one setting does not necessarily work in another. In short, guideline implementation and change of practice is complex and messy. The purpose of this article is to discuss the implementation of clinical practice guidelines using the Promoting Action on Research Implementation in Health Services framework. More specifically, 3 key components are highlighted: (1) the evidence base for guideline recommendations, (2) the clinical context where guidelines are to be implemented, and (3) the nature of facilitation needed to ensure a successful change process. An overview of the literature in the field is provided, and the authors' experiences are shared, and a few recommendations are tentatively provided.  相似文献   
99.
100.
The objective of the present investigations was to develop oblong tablets which expand after contact with gastrointestinal fluids within a few minutes to a length of 4-6 cm and which should remain in the stomach for a prolonged period of time due to their size. The tablets were prepared from riboflavin-containing collagen sponges using a computer controlled single punch tablet machine. The collagen material was compressed to oblong tablets with dimensions of 3.5 mm x 9 mm x 18 mm. In vitro investigations were carried out to characterise drug release. The model drug riboflavin was released from the collagen tablets over 12h. The gastrointestinal retention time of the new dosage form was indirectly estimated by determining the duration of riboflavin excretion after oral intake of the tablet. A crossover in vivo study with 12 healthy male and female subjects was performed. The renal excretion of riboflavin was measured after oral administration of collagen tablets and small sustained release hydrocolloid tablets as reference preparation. The amount of riboflavin excreted into the urine was enhanced after administration of the expanding collagen tablets in comparison with the hydrocolloid tablets. The differences were statistically significant after 5, 6, 8, 9, 10 and 12 h.  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