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   342196篇
  免费   57624篇
  国内免费   1045篇
耳鼻咽喉   4613篇
儿科学   12895篇
妇产科学   6502篇
基础医学   52455篇
口腔科学   15291篇
临床医学   34280篇
内科学   82445篇
皮肤病学   13768篇
神经病学   37191篇
特种医学   9868篇
外国民族医学   27篇
外科学   43211篇
综合类   1859篇
现状与发展   1篇
一般理论   150篇
预防医学   31524篇
眼科学   5967篇
药学   22955篇
中国医学   1976篇
肿瘤学   23887篇
  2023年   1749篇
  2022年   3874篇
  2021年   8172篇
  2020年   9103篇
  2019年   16170篇
  2018年   17392篇
  2017年   16671篇
  2016年   17537篇
  2015年   18228篇
  2014年   20576篇
  2013年   23912篇
  2012年   22836篇
  2011年   23585篇
  2010年   18962篇
  2009年   14199篇
  2008年   17665篇
  2007年   17167篇
  2006年   16062篇
  2005年   15776篇
  2004年   14683篇
  2003年   13346篇
  2002年   11028篇
  2001年   6350篇
  2000年   6101篇
  1999年   5308篇
  1998年   2461篇
  1997年   2010篇
  1996年   1892篇
  1995年   1593篇
  1994年   1564篇
  1993年   1378篇
  1992年   3007篇
  1991年   2839篇
  1990年   2602篇
  1989年   2598篇
  1988年   2334篇
  1987年   2145篇
  1986年   2014篇
  1985年   1906篇
  1984年   1421篇
  1983年   1161篇
  1982年   763篇
  1981年   672篇
  1980年   649篇
  1979年   1020篇
  1978年   723篇
  1977年   561篇
  1975年   611篇
  1974年   616篇
  1973年   591篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Journal of Medical Ultrasonics - Chronic liver disease is still a major problem because disease progression will ultimately lead to liver cirrhosis. Portal hypertension is the hallmark in advanced...  相似文献   
2.
ObjectiveSpinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two-year follow-up period.Materials and methodsThe study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two-year follow-up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries.ResultsHigher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001).ConclusionsHigher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation.  相似文献   
3.
4.
5.

Background

Hyperglycaemia is common in patients with acute brain injury admitted to an intensive care unit (ICU). Many studies have found associations between development of hyperglycaemia and increased mortality in hospitalised patients. However, the optimal target for blood glucose control is unknown. We want to conduct a systematic review with meta-analysis and trial sequential analysis to explore the beneficial and harmful effects of restrictive versus liberal glucose control on patient outcomes in adults with severe acute brain injury.

Methods

We will systematically search medical databases including CENTRAL, Embase, MEDLINE and trial registries. We will search the following websites for ongoing or unpublished trials: http://www.controlled-trials.com/ , http://www.clinicaltrials.gov/ , www.eudraCT.com , http://centerwatch.com/ , The Cochrane Library's CENTRAL, PubMed, EMBASE, Science Citation Index Expanded and CINAHL. Two authors will independently review and select trials and extract data. We will include randomised trials comparing levels of glucose control in our analyses and observational studies will be included to address potential harms. The primary outcomes are defined as all-cause mortality, functional outcome and health-related quality of life. Secondary outcomes include serious adverse events including hypoglycaemia, length of ICU stay and duration of mechanical ventilation, and explorative outcomes including intracranial pressure and infection. Trial Sequential Analysis will be used to investigate the risk of type I error due to repetitive testing and to further explore imprecision. Quality of trials will be evaluated using the Cochrane Risk of Bias tool, and quality of evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach.

Discussion

The results of the systematic review will be disseminated through peer-reviewed publication. With the review, we hope to inform future randomised clinical trials and improve clinical practice.  相似文献   
6.
7.
Metformin, a drug for type 2 diabetes mellitus, has shown therapeutic effects for various cancers. However, it had no beneficial effects on the survival rate of human malignant mesothelioma (HMM) patients. The present study was performed to elucidate the underlying mechanism of metformin resistance in HMM cells. Glucose‐starved HMM cells had enhanced resistance to metformin, demonstrated by decreased apoptosis and autophagy and increased cell survival. These cells showed abnormalities in mitochondria, such as decreased ATP synthesis, morphological elongation, altered mitochondrial permeability transition pore and hyperpolarization of mitochondrial membrane potential (MMP). Intriguingly, Mdr1 was significantly upregulated in mitochondria but not in cell membrane. The upregulated mitochondrial Mdr1 was reversed by treatment with carbonyl cyanide m‐chlorophenyl hydrazone, an MMP depolarization inducer. Furthermore, apoptosis and autophagy were increased in multidrug resistance protein 1 knockout HMM cells cultured under glucose starvation with metformin treatment. The data suggest that mitochondrial Mdr1 plays a critical role in the chemoresistance to metformin in HMM cells, which could be a potential target for improving its therapeutic efficacy.  相似文献   
8.
9.
We report a case of benign lymphoplasmacytic plaque (LPP) in a child. These asymptomatic erythematous papulonodular lesions are an emerging clinicopathological entity. Herein, we describe a previously unreported site for LPP lesions, namely, the volar wrist and the distal ipsilateral palm.  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