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   19129篇
  免费   1219篇
  国内免费   136篇
耳鼻咽喉   166篇
儿科学   446篇
妇产科学   380篇
基础医学   2234篇
口腔科学   758篇
临床医学   1808篇
内科学   4070篇
皮肤病学   400篇
神经病学   1193篇
特种医学   469篇
外国民族医学   5篇
外科学   2509篇
综合类   491篇
一般理论   15篇
预防医学   1596篇
眼科学   740篇
药学   1830篇
中国医学   213篇
肿瘤学   1161篇
  2024年   23篇
  2023年   233篇
  2022年   537篇
  2021年   1113篇
  2020年   724篇
  2019年   883篇
  2018年   1038篇
  2017年   738篇
  2016年   797篇
  2015年   806篇
  2014年   1074篇
  2013年   1233篇
  2012年   1685篇
  2011年   1734篇
  2010年   1029篇
  2009年   774篇
  2008年   1146篇
  2007年   1033篇
  2006年   866篇
  2005年   742篇
  2004年   595篇
  2003年   485篇
  2002年   421篇
  2001年   53篇
  2000年   64篇
  1999年   64篇
  1998年   52篇
  1997年   49篇
  1996年   47篇
  1995年   40篇
  1994年   24篇
  1993年   46篇
  1992年   28篇
  1991年   27篇
  1990年   21篇
  1989年   23篇
  1988年   21篇
  1987年   11篇
  1986年   16篇
  1985年   13篇
  1984年   21篇
  1983年   17篇
  1982年   16篇
  1981年   11篇
  1980年   13篇
  1979年   15篇
  1978年   11篇
  1976年   11篇
  1974年   10篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Objective: To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.

Design/Methods: VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3?h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45?min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15?ml/kg of PRBC transfusion was given over 3?h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48?h after the transfusion.

Results: Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48?h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.

Conclusions: PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24?h post-transfusion.  相似文献   
4.
ABSTRACT

Purpose

To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163+ M2 macrophages in proliferative diabetic retinopathy (PDR).  相似文献   
5.
6.
7.
8.
9.
Doxorubicin (DOX) is the most commonly used anticancer drug; however, it has limited use because prolonged administration may result in severe cardiotoxicity. Simvastatin (SIM), generally prescribed for hypercholesterolaemia, has also shown salubrious results in the monotherapy or combinational drug therapy of different cancers in various models. Nanoparticle drug delivery systems are a novel way of improving therapeutics and also improving the absorption and specificity of drugs towards tumour cells. In this study, we exploited this technology to increase drug specificity and minimize imminent adverse effects. In this study, the antitumour activity of the combination formulas of DOX and SIM, either loaded in water (DOX‐SIM‐Solution) or nanoemulsions (NEs) (DOX‐SIM‐NE), was evaluated in a Swiss albino mouse model of Ehrlich ascites carcinoma. The anticancer effect was assessed by quantifying the change in body weight, mean survival time, and percent increase in lifespan (%ILS), determining haematological and serum biochemical parameters (liver function test, kidney function test and lipid profile parameters) as well as studying the histopathological alterations in liver tissues. We observed a clear increase in %ILS of the DOX‐SIM‐Solution group (265.30) that was double the %ILS of the DOX‐SIM‐NE group (134.70). However, DOX‐SIM‐NE had a non‐toxic effect on the haematological parameters, whereas DOX‐SIM‐Solution increased the levels of haemoglobin and lymphocytes. Furthermore, the encapsulation of SIM and DOX into NEs improved the levels of all serum biochemical parameters compared to the DOX‐SIM‐Solution. A reduction in the side effects of DOX‐SIM‐NE on the liver was also established using light microscopy, which revealed that the morphologies of the hepatocytes of the mice were less affected by administration of the DOX‐SIM‐NE treatment than with the DOX‐SIM‐Solution treatment. The study showed that incorporating SIM into the DOX‐loaded‐NE formulation remarkably improved its efficiency and simultaneously reduced its adverse effects.  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