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   1488836篇
  免费   98839篇
  国内免费   3315篇
耳鼻咽喉   21884篇
儿科学   46038篇
妇产科学   43396篇
基础医学   207504篇
口腔科学   44613篇
临床医学   124688篇
内科学   289093篇
皮肤病学   33698篇
神经病学   115295篇
特种医学   62415篇
外国民族医学   517篇
外科学   231490篇
综合类   31962篇
现状与发展   6篇
一般理论   438篇
预防医学   105851篇
眼科学   34928篇
药学   110477篇
  4篇
中国医学   3110篇
肿瘤学   83583篇
  2018年   14935篇
  2017年   13120篇
  2016年   13446篇
  2015年   16236篇
  2014年   20457篇
  2013年   28142篇
  2012年   41485篇
  2011年   38824篇
  2010年   22576篇
  2009年   23527篇
  2008年   35241篇
  2007年   38936篇
  2006年   39714篇
  2005年   45985篇
  2004年   46489篇
  2003年   41327篇
  2002年   36366篇
  2001年   66462篇
  2000年   66438篇
  1999年   59223篇
  1998年   15036篇
  1997年   13638篇
  1996年   13174篇
  1995年   12463篇
  1992年   47569篇
  1991年   46373篇
  1990年   45867篇
  1989年   44624篇
  1988年   41639篇
  1987年   41054篇
  1986年   39305篇
  1985年   36992篇
  1984年   27515篇
  1983年   23217篇
  1982年   13409篇
  1981年   12151篇
  1979年   26822篇
  1978年   18863篇
  1977年   16156篇
  1976年   14615篇
  1975年   17144篇
  1974年   20507篇
  1973年   19722篇
  1972年   18931篇
  1971年   17945篇
  1970年   16964篇
  1969年   16334篇
  1968年   15307篇
  1967年   13810篇
  1966年   12871篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
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   
92.
93.

Introduction

Little is known about dementia incidence in diverse populations of oldest-old, the age group with highest dementia incidence.

Methods

Incident dementia diagnoses from 1/1/2010 to 9/30/2015 were abstracted from medical records for 2350 members of an integrated health care system in California (n = 1702 whites, n = 375 blacks, n = 105 Latinos, n = 168 Asians) aged ≥90 in 2010. We estimated race/ethnicity-specific age-adjusted dementia incidence rates and implemented Cox proportional hazards models and Fine and Gray competing risk of death models adjusted for demographics and comorbidities in midlife and late-life.

Results

Dementia incidence rates (n = 771 cases) were lowest among Asians (89.9/1000 person-years), followed by whites (96.9/1000 person-years), Latinos (105.8/1000 person-years), and blacks (121.5/1000 person-years). Cox regression and competing risk models estimated 28% and 36% higher dementia risk for blacks versus whites adjusting for demographics and comorbidities.

Discussion

Patterns of racial/ethnic disparities in dementia seen in younger older adults continue after the age of 90 years, though smaller in magnitude.  相似文献   
94.
95.
96.
97.
Donor site morbidity following radial forearm flap (RFF) harvest remains a controversial issue. The aim of this meta-analysis was to answer the question “Are the range of wrist movements (range of motion, ROM) and hand strength affected after RFF harvesting?” The PubMed, Embase, Scopus, and Cochrane Library electronic databases were systematically searched (to December 2019). Self-controlled studies evaluating hand biomechanics after RFF harvest were included. Weighted mean differences with 95% confidence intervals were calculated using the random-effects model. The outcome variables were ROM, forearm movements, grip, and pinch strengths. Thirteen studies involving a total of 335 patients were included. With the exception of grip strength and supination, which showed statistically significant reductions of about 2.40 kg and 2.86° (P < 0.05), all other ROM, forearm movements, and pinch strengths showed an insignificant difference when the operated hand was compared to the non-operated hand (P > 0.05). Regression analysis showed that the method of donor site closure and size of the donor site defect had an insignificant impact on hand biomechanics. This study confirms the lack of discernible biomechanical morbidity after RFF transfer. The minimal reduction in hand biomechanics after RFF is considered to be clinically negligible.  相似文献   
98.
99.
100.
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