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   7685篇
  免费   475篇
  国内免费   34篇
耳鼻咽喉   60篇
儿科学   235篇
妇产科学   176篇
基础医学   1034篇
口腔科学   176篇
临床医学   600篇
内科学   1593篇
皮肤病学   133篇
神经病学   656篇
特种医学   297篇
外科学   874篇
综合类   35篇
一般理论   1篇
预防医学   893篇
眼科学   310篇
药学   570篇
中国医学   9篇
肿瘤学   542篇
  2023年   60篇
  2022年   70篇
  2021年   251篇
  2020年   124篇
  2019年   195篇
  2018年   212篇
  2017年   186篇
  2016年   152篇
  2015年   231篇
  2014年   216篇
  2013年   307篇
  2012年   522篇
  2011年   496篇
  2010年   260篇
  2009年   214篇
  2008年   403篇
  2007年   414篇
  2006年   430篇
  2005年   385篇
  2004年   409篇
  2003年   368篇
  2002年   340篇
  2001年   220篇
  2000年   189篇
  1999年   165篇
  1998年   75篇
  1997年   63篇
  1996年   79篇
  1995年   42篇
  1994年   39篇
  1993年   26篇
  1992年   98篇
  1991年   79篇
  1990年   77篇
  1989年   84篇
  1988年   96篇
  1987年   64篇
  1986年   63篇
  1985年   61篇
  1984年   55篇
  1983年   26篇
  1982年   19篇
  1981年   19篇
  1979年   25篇
  1978年   31篇
  1976年   22篇
  1975年   21篇
  1974年   22篇
  1973年   34篇
  1968年   19篇
排序方式: 共有8194条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
5.
Introduction

Visible light spectroscopy (VLS) represents a sensitive, non-invasive method to quantify tissue oxygen levels and detect hypoxemia. The aim of this study was to assess the microperfusion patterns of the gastric pouch during laparoscopic Roux-en-Y gastric bypass (LRYGB) using the VLS technique.

Methods

Twenty patients were enrolled. Tissue oxygenation (StO2%) measurements were performed at three different localizations of the gastric wall, prior and after the creation of the gastric pouch, and after the creation of the gastro-jejunostomy.

Results

Prior to the creation of the gastric pouch, the lowest StO2% levels were observed at the level of the distal esophagus with a median StO2% of 43 (IQR 40.8–49.5). After the creation of the gastric pouch and after the creation of the gastro-jejunostomy, the lowest StO2% levels were recorded at the level of the His angle with median values of 29% (IQR 20–38.5) and 34.5% (IQR 19–39), respectively. The highest mean StO2 reduction was recorded at the level of the His angle after the creation of the gastric pouch, and it was 18.3% (SD ± 18.1%, p < 0.001). A reduction of StO2% was recorded at all localizations after the formation of the gastro-jejunostomy compared to the beginning of the operation, but the mean differences of the StO2% levels were statistically significant only at the resection line of the pouch and at the His angle (p = 0.044 and p < 0.001, respectively).

Conclusion

Gastric pouch demonstrates reduction of StO2% during LRYGB. VLS is a useful technique to assess microperfusion patterns of the stomach during LRYGB.

Graphical abstract
  相似文献   
6.
We compared the functional status of the hypothalamic dopaminergic tone in patients given an allogeneic hematopoietic stem cell transplantation (allo-HSCT) with chronic graft-versus-host disease (GVHD) with that observed in patients with allo-HSCT without chronic GVHD and in healthy controls. The effect of acute dopaminergic blockade with intravenous metoclopramide on serum prolactin (PRL) concentrations was evaluated. Twenty volunteers, 20 to 52 years of age, seronegative for both hepatitis C virus and the human immunodeficiency virus, were studied: (1) 10 clinically healthy men (group 1), and (2) 9 patients with leukemia, and 1 patient with refractory aplastic anemia who underwent allo-HSCT, 5 of whom (3 men and 2 women) developed chronic GVHD (group 2), and 5 (3 men and 2 women) who did not develop chronic GVHD (group 3). Serum PRL concentrations were measured both fasting and after intravenous administration of metoclopramide (10-mg bolus). The area under the PRL curve was calculated. Patients in group 2 were older than those in groups 1 and 3 (P<.018), but their body mass index was similar. Fasting serum PRL concentrations were similar among the 3 groups; however, group 2 had higher PRL concentrations throughout the test (P<.001) and a greater area under the PRL curve than groups 1 and 3 (P<.001), without differences between the last 2 groups. The differences remained significant after adjustment for age (P<.01). Our results in a small group of patients with chronic GVHD after allo-HSCT suggest the existence of an increased functional level of their hypothalamic dopamine tone, which would favor a tendency toward a diminished endogenous production, release of pituitary PRL, or both. This could represent an adaptive mechanism aiming to maintain circulating PRL concentrations within a physiological range.  相似文献   
7.
8.
A monoclonal antibody raised by immunization of BALB/c mice with erythrocytic stages of Plasmodium vivax was shown to react with asexual erythrocytic stages of P. chabaudi. The cross-reactivity molecules are antigens of 200 and 148 kDa in P. vivax and of 190 and 70 kDa in P. chabaudi. Immunofluorescence studies of the erythrocytic stages of P. vivax and P. chabaudi indicated that expression of these antigens increased as the parasites' developed from the ring stage to the schizont stage. In the mature trophozoites of P. chabaudi, immunoelectron microscopy revealed clusters of antigen distributed in the cytoplasm of the parasitized erythrocyte. In the schizont, packets of antigen were found associated with the parasitophorous vacuole and the cytoplasm of the infected host cell. Received: 19 March 1996 / Accepted: 28 August 1996  相似文献   
9.
Several articles have been published that bring attention to the destructive potential of tire explosions. Although the severity of tire explosion injuries to the head and neck region is well established, only one previous article has reported injuries to the upper extremity. Fourteen patients with upper extremity tire explosion injuries have been treated by us from 1980 to 1988. Each injury was caused by single-piece wheel assemblies, as opposed to multipiece wheel assemblies, which have traditionally been associated with the injury. Three representative patient reports are discussed. Prevention of this injury can be achieved by increased public awareness, formal industrial safety training, tire servicing with dedicated equipment including restraining devices or barriers, complete evaluation of wheel/tire serviceability before tire mounting, separation of servicing of single and multipiece wheels, and complete tire deflation before servicing.  相似文献   
10.
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