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   1460836篇
  免费   101095篇
  国内免费   3189篇
耳鼻咽喉   21980篇
儿科学   44927篇
妇产科学   41759篇
基础医学   204988篇
口腔科学   43678篇
临床医学   122095篇
内科学   284808篇
皮肤病学   33901篇
神经病学   118317篇
特种医学   60188篇
外国民族医学   455篇
外科学   228888篇
综合类   31953篇
现状与发展   6篇
一般理论   466篇
预防医学   98101篇
眼科学   35116篇
药学   108856篇
  3篇
中国医学   3286篇
肿瘤学   81349篇
  2018年   14131篇
  2016年   13281篇
  2015年   14892篇
  2014年   19851篇
  2013年   29732篇
  2012年   39953篇
  2011年   41329篇
  2010年   24491篇
  2009年   23216篇
  2008年   39960篇
  2007年   43681篇
  2006年   44198篇
  2005年   43290篇
  2004年   41968篇
  2003年   40870篇
  2002年   40257篇
  2001年   67605篇
  2000年   69181篇
  1999年   58815篇
  1998年   15788篇
  1997年   14337篇
  1996年   13638篇
  1995年   12779篇
  1994年   11983篇
  1992年   44197篇
  1991年   42593篇
  1990年   41877篇
  1989年   40748篇
  1988年   38006篇
  1987年   37472篇
  1986年   35834篇
  1985年   33994篇
  1984年   25541篇
  1983年   21615篇
  1982年   13082篇
  1981年   11953篇
  1979年   24701篇
  1978年   17643篇
  1977年   15307篇
  1976年   13818篇
  1975年   15839篇
  1974年   18708篇
  1973年   18129篇
  1972年   17421篇
  1971年   16301篇
  1970年   15455篇
  1969年   14826篇
  1968年   13951篇
  1967年   12453篇
  1966年   11610篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
101.
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   
102.
103.

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   
104.
105.
106.
107.
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   
108.
109.
110.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Gefahrstoffe sind in der Arbeitswelt allgegenwärtig. Beschäftigte aus allen Branchen sind bei ihrer Arbeit mit...  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