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   233184篇
  免费   52006篇
  国内免费   1395篇
耳鼻咽喉   3664篇
儿科学   7053篇
妇产科学   4304篇
基础医学   39223篇
口腔科学   8102篇
临床医学   27138篇
内科学   52120篇
皮肤病学   11599篇
神经病学   24821篇
特种医学   10495篇
外国民族医学   3篇
外科学   35144篇
综合类   2382篇
现状与发展   5篇
一般理论   102篇
预防医学   13693篇
眼科学   5695篇
药学   19216篇
  3篇
中国医学   2529篇
肿瘤学   19294篇
  2023年   814篇
  2022年   2191篇
  2021年   6232篇
  2020年   7288篇
  2019年   13726篇
  2018年   13968篇
  2017年   13948篇
  2016年   15512篇
  2015年   16948篇
  2014年   18266篇
  2013年   20141篇
  2012年   16984篇
  2011年   16558篇
  2010年   15802篇
  2009年   11234篇
  2008年   11450篇
  2007年   10187篇
  2006年   9434篇
  2005年   8817篇
  2004年   7858篇
  2003年   6952篇
  2002年   6193篇
  2001年   5144篇
  2000年   4711篇
  1999年   3551篇
  1998年   1370篇
  1997年   1040篇
  1996年   980篇
  1995年   888篇
  1994年   777篇
  1993年   665篇
  1992年   1601篇
  1991年   1594篇
  1990年   1369篇
  1989年   1256篇
  1988年   1162篇
  1987年   1041篇
  1986年   1024篇
  1985年   889篇
  1984年   656篇
  1983年   569篇
  1982年   404篇
  1981年   389篇
  1980年   342篇
  1979年   527篇
  1978年   411篇
  1977年   393篇
  1976年   348篇
  1974年   363篇
  1973年   329篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Introduction: Malnutrition increases the risk of cancer treatment-related complications. Nutritional intervention is beneficial for the outcomes of outpatients with cancer. This study investigated the impacts of nutrition consultation and care on energy intake and weight change in inpatients receiving cancer treatment.

Methods: We conducted a longitudinal study, enrolling 3221 inpatients with head and neck, lung, hepatobiliary, upper gastrointestinal, colorectal, breast, or gynecological cancer who received at least two nutrition consultations between April 2010 and July 2015. In every consultation, a dietitian calculated the total energy requirement and the actual energy intake was assessed using a 24-h dietary recall.

Results: Patients with head and neck cancer lost the most weight (1.16?kg/mo). For every consultation, a 0.03-kg weight gain per month was observed (P?=?0.001). The average energy consumption percentage (% estimated energy requirement) at the third consultation was 87.0%. After controlling for potential covariates, the energy consumption percentages at the third, fourth, fifth–seventh, eighth, and subsequent consultations were significantly higher than those at the first consultation (P?<?0.05).

Conclusion: For oncology inpatients, routine screening and at least three active nutrition consultations with dietitians effectively improved energy intake and preserved body weight.  相似文献   

102.
103.
A pathological feature in atherosclerosis is the dysfunction and death of vascular endothelial cells (EC). Oxidized low‐density lipoprotein (LDL), known to accumulate in the atherosclerotic arterial walls, impairs endothelium‐dependent relaxation and causes EC apoptosis. A major bioactive ingredient of the oxidized LDL is lysophosphatidylcholine (LPC), which at higher concentrations causes apoptosis and necrosis in various EC. There is hitherto no report on LPC‐induced cytotoxicity in brain EC. In this work, we found that LPC caused cytosolic Ca2+ overload, mitochondrial membrane potential decrease, p38 activation, caspase 3 activation and eventually apoptotic death in mouse cerebral bEND.3 EC. In contrast to reported reactive oxygen species (ROS) generation by LPC in other EC, LPC did not trigger ROS formation in bEND.3 cells. Pharmacological inhibition of p38 alleviated LPC‐inflicted cell death. We examined whether heparin could be cytoprotective: although it could not suppress LPC‐triggered Ca2+ signal, p38 activation and mitochondrial membrane potential drop, it did suppress LPC‐induced caspase 3 activation and alleviate LPC‐inflicted cytotoxicity. Our data suggest LPC apoptotic death mechanisms in bEND.3 might involve mitochondrial membrane potential decrease and p38 activation. Heparin is protective against LPC cytotoxicity and might intervene steps between mitochondrial membrane potential drop/p38 activation and caspase 3 activation.  相似文献   
104.
While therapeutic approaches for psoriasis are widely available, preventive regimens are lacking. We aimed to determine whether improvements in epidermal function could prevent psoriasis relapse. Two self‐controlled cohort studies were designed, enrolling two cohorts of patients with psoriasis (n = 30 and n = 60) to be treated topically with an in‐house‐prepared emollient or ATOPALM® cream applied twice daily to one forearm for 20 and 30 days, respectively, while the same sites on the contralateral arm served as the untreated control. Epidermal function on both arms was assessed prior to and at the end of the trials. Delayed relapse on the treated arm was seen in 54.5% and 71% of patients in the first and second cohort, respectively. The time of psoriatic relapse correlated with the extent of abnormalities in baseline epidermal function. These results suggest that improvements in epidermal function with topical emollients can prevent/attenuate the development of psoriasis.  相似文献   
105.
106.
Erythema induratum of Bazin (EIB) is a form of tuberculid resulting from hypersensitivity to tuberculosis antigen. EIB occurs most commonly in middle‐aged women and is not typically seen in children. Here, we present a rare case of EIB, presenting as a chronic nodular panniculitis, in a 10‐year‐old Korean boy.  相似文献   
107.

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   
108.
109.
110.
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