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   272253篇
  免费   16582篇
  国内免费   1054篇
耳鼻咽喉   3121篇
儿科学   8912篇
妇产科学   6026篇
基础医学   38142篇
口腔科学   10392篇
临床医学   21885篇
内科学   61441篇
皮肤病学   6958篇
神经病学   24627篇
特种医学   7855篇
外国民族医学   27篇
外科学   30711篇
综合类   1836篇
现状与发展   1篇
一般理论   112篇
预防医学   27045篇
眼科学   4953篇
药学   17541篇
中国医学   998篇
肿瘤学   17306篇
  2023年   1711篇
  2022年   2805篇
  2021年   7045篇
  2020年   4571篇
  2019年   6343篇
  2018年   8166篇
  2017年   6211篇
  2016年   6360篇
  2015年   7165篇
  2014年   9546篇
  2013年   12358篇
  2012年   19017篇
  2011年   19654篇
  2010年   10351篇
  2009年   9203篇
  2008年   15522篇
  2007年   16203篇
  2006年   15007篇
  2005年   14992篇
  2004年   13777篇
  2003年   12585篇
  2002年   10124篇
  2001年   5666篇
  2000年   5485篇
  1999年   5118篇
  1998年   2357篇
  1997年   1962篇
  1996年   1851篇
  1995年   1556篇
  1994年   1526篇
  1993年   1334篇
  1992年   3067篇
  1991年   2891篇
  1990年   2652篇
  1989年   2616篇
  1988年   2383篇
  1987年   2179篇
  1986年   2063篇
  1985年   1929篇
  1984年   1443篇
  1983年   1192篇
  1982年   754篇
  1981年   636篇
  1980年   623篇
  1979年   1037篇
  1978年   715篇
  1977年   572篇
  1975年   619篇
  1974年   642篇
  1973年   623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.
3.

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 We will search the following websites for ongoing or unpublished trials: http://www.controlled-trials.com/ , http://www.clinicaltrials.gov/ , www.eudraCT.com , http://centerwatch.com/ , The Cochrane Library's CENTRAL,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   
4.
5.
6.
7.
The regulation of food intake is a complex mechanism, and the hypothalamus is the main central structure implicated. In particular, the arcuate nucleus appears to be the most critical area in the integration of multiple peripheral signals.Among these signals, those originating from the white adipose tissue and the gastrointestinal tract are known to be involved in the regulation of food intake.The present paper focuses on adiponectin, an adipokine secreted by white adipose tissue, which is reported to have a role in the control of feeding by acting centrally. The recent observation that adiponectin is also able to influence gastric motility raises the question of whether this action represents an additional peripheral mechanism that concurs with the central effects of the hormone on food intake. This possibility, which represents an emerging aspect correlating the central and peripheral effects of adiponectin in the hunger-satiety cycle, is discussed in the present paper.  相似文献   
8.
Neorickettsia helminthoeca (NH), the agent of salmon poisoning disease or canine neorickettiosis (CN), is a bacterial endosymbiont of the nematode Nanophyetus salmincola, and infections are spreading among specific fish‐eating mammalians. This article describes the pathologic and immunohistochemical findings associated with spontaneous NH‐induced infections in dogs from Southern Brazil. The principal pathologic findings were hypertrophy of Peyer patches and lymphadenopathy with lymphocytic proliferation, chronic interstitial pneumonia, and chronic enteritis associated with positive intralesional immunoreactivity to antigens of NH within macrophages and histiocytes. Positive immunoreactivity against canine parvovirus‐2 (CPV‐2) or/and canine distemper virus was not detected in the evaluated intestinal segments or in the samples from the cerebellum and lungs, respectively, from the dogs evaluated. These findings demonstrated that NH was involved in the enteric, pulmonary, and lymphoid lesions herein described, and provide additional information to confirm the occurrence of this bacterial endosymbiont within this geographical location. It is proposed that chronic pneumonia should be considered as a pathologic manifestation of NH‐induced infections. Additionally, our results show that the occurrences of CN seem to be underdiagnosed in Southern Brazil due to the confusion with the incidence of CPV‐2.  相似文献   
9.
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