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   49076篇
  免费   3398篇
  国内免费   652篇
耳鼻咽喉   984篇
儿科学   793篇
妇产科学   876篇
基础医学   7357篇
口腔科学   922篇
临床医学   4050篇
内科学   10390篇
皮肤病学   1587篇
神经病学   3408篇
特种医学   3073篇
外科学   6583篇
综合类   897篇
现状与发展   2篇
一般理论   20篇
预防医学   1980篇
眼科学   1611篇
药学   3968篇
中国医学   546篇
肿瘤学   4079篇
  2023年   299篇
  2022年   812篇
  2021年   1876篇
  2020年   1003篇
  2019年   1338篇
  2018年   1609篇
  2017年   1242篇
  2016年   1746篇
  2015年   2325篇
  2014年   2812篇
  2013年   3014篇
  2012年   4511篇
  2011年   4305篇
  2010年   2663篇
  2009年   2269篇
  2008年   3038篇
  2007年   2833篇
  2006年   2598篇
  2005年   2322篇
  2004年   1866篇
  2003年   1605篇
  2002年   1408篇
  2001年   802篇
  2000年   766篇
  1999年   603篇
  1998年   256篇
  1997年   229篇
  1996年   158篇
  1995年   142篇
  1994年   126篇
  1993年   113篇
  1992年   205篇
  1991年   240篇
  1990年   179篇
  1989年   185篇
  1988年   179篇
  1987年   182篇
  1986年   136篇
  1985年   120篇
  1984年   92篇
  1983年   95篇
  1982年   50篇
  1980年   49篇
  1979年   85篇
  1978年   56篇
  1977年   67篇
  1975年   50篇
  1974年   50篇
  1973年   49篇
  1972年   46篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
3.
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   
4.
5.
Rhabdomyolysis is a syndrome of skeletal muscle injury with release of cellular constituents such as potassium,phosphate,urate and intracellular proteins such as myoglobin into the circulation,which may cause complications including acute kidney injury,electrolyte disturbance and cardiac instability.Abnormal liver function tests are frequently observed in cases of severe rhabdomyolysis.Typically,there is an increase in serum aminotransferases,namely aspartate aminotransferase and alanine aminotransferase.This raises the question of liver injury and often triggers a pathway of investigation which may lead to a liver biopsy.However,muscle can also be a source of the increased aminotransferase activity.This review discusses the dilemma of finding abnormal liver function tests in the setting of muscle injury and the potential implications of such an association.It delves into some of the clinical and experimental evidence for correlating muscle injury to raised aminotransferases,and discusses pathophysiological mechanisms such as oxidative stress which may cause actual liver injury.Serum aminotransferases lack tissue specificity to allow clinicians to distinguish primary liver injury from muscle injury.This review also explores potential approaches to improve the accuracy of our diagnostic tools,so that excessive or unnecessary liver investigations can be avoided.  相似文献   
6.
7.
In this paper, we introduce a new type of troubled-cell indicator to improve hybrid weighted essentially non-oscillatory (WENO) schemes for solving the hyperbolic conservation laws. The hybrid WENO schemes selectively adopt the high-order linear upwind scheme or the WENO scheme to avoid the local characteristic decompositions and calculations of the nonlinear weights in smooth regions. Therefore, they can reduce computational cost while maintaining non-oscillatory properties in non-smooth regions. Reliable troubled-cell indicators are essential for efficient hybrid WENO methods. Most of troubled-cell indicators require proper parameters to detect discontinuities precisely, but it is very difficult to determine the parameters automatically. We develop a new troubled-cell indicator derived from the mean value theorem that does not require any variable parameters. Additionally, we investigate the characteristics of indicator variable; one of the conserved properties or the entropy is considered as indicator variable. Detailed numerical tests for 1D and 2D Euler equations are conducted to demonstrate the performance of the proposed indicator. The results with the proposed troubled-cell indicator are in good agreement with pure WENO schemes. Also the new indicator has advantages in the computational cost compared with the other indicators.  相似文献   
8.
ABSTRACT

Purpose

Work-related eye injuries have been reported with a variety of epidemiologic and clinical characteristics. We aimed to identify epidemiologic characteristics of work-related eye injuries and risk factors associated with severe injury in a large metropolitan city.  相似文献   
9.
Abstract

Objective

Ras wild-type metastatic colorectal cancers (mCRC) may be treated with anti-vascular endothelial growth factor (VEGF) or anti-epidermal growth factor receptor (EGFR) agents. We aim to estimate patients’ preferences for mCRC treatment and relative importance of cost, efficacy improvement, avoidance of side effects and therapy convenience, and relative uptake between profiles that resemble Bevacizumab (anti-VEGF) and Cetuximab (anti-EGFR), two commonly prescribed mCRC targeted therapies.  相似文献   
10.
A classic pilomatricoma, which usually presents with an asymptomatic, solitary, firm, subcutaneous nodule in the head, neck, or extremities of the paediatric population, is easily diagnosed based on its characteristic clinical and histopathological features. However, its variants often pose particular diagnostic challenges to clinicians due to their rarity and diverse clinicopathological features. We present a new pseudocystic variant, manifesting as solid lesions floating in a fluid‐filled sac.  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