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   712篇
  免费   39篇
  国内免费   14篇
电工技术   5篇
综合类   80篇
化学工业   179篇
金属工艺   19篇
机械仪表   38篇
建筑科学   33篇
矿业工程   9篇
能源动力   5篇
轻工业   90篇
水利工程   12篇
石油天然气   3篇
武器工业   5篇
无线电   52篇
一般工业技术   63篇
冶金工业   115篇
原子能技术   5篇
自动化技术   52篇
  2023年   24篇
  2022年   11篇
  2021年   98篇
  2020年   32篇
  2019年   23篇
  2018年   23篇
  2017年   11篇
  2016年   17篇
  2015年   35篇
  2014年   28篇
  2013年   44篇
  2012年   37篇
  2011年   32篇
  2010年   40篇
  2009年   39篇
  2008年   31篇
  2007年   43篇
  2006年   30篇
  2005年   24篇
  2004年   37篇
  2003年   25篇
  2002年   18篇
  2001年   16篇
  2000年   6篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   9篇
  1994年   3篇
  1991年   4篇
  1990年   3篇
  1989年   1篇
  1986年   1篇
  1985年   2篇
  1982年   2篇
  1981年   1篇
  1974年   1篇
  1966年   1篇
  1965年   2篇
  1964年   2篇
  1962年   1篇
  1961年   1篇
  1960年   1篇
  1958年   1篇
排序方式: 共有765条查询结果,搜索用时 15 毫秒
81.
Non-ischemic dilated cardiomyopathy encompasses a wide spectrum of myocardial disorders, characterized by left ventricular dilatation with systolic impairment and increased risk of sudden cardiac death. In spite of all the therapeutic progress that has been made in recent years, dilated cardiomyopathy continues to be an important cause of cardiac transplant, being associated with an enormous cost burden for health care systems worldwide. Predicting the prognosis of patients with dilated cardiomyopathy is essential to individualize treatment. Late gadolinium enhancement-cardiac magnetic resonance imaging, microvolt T-wave alternans, and genetic testing have emerged as powerful tools in predicting sudden cardiac death occurrence and maximizing patient’s selection. Despite all these new diagnostic modalities, additional tests to complement or replace current tools are required for better risk stratification. Therefore, biomarkers are an easy and important tool that can help to detect patients at risk of adverse cardiovascular events. Additionally, identifying potential biomarkers involved in dilated cardiomyopathy can provide us important information regarding the diagnostic, prognostic, risk stratification, and response to treatment for these patients. Many potential biomarkers have been studied in patients with dilated cardiomyopathy, but only a few have been adopted in current practice. Therefore, the aim of our review is to provide the clinicians with an update on the well-known and novel biomarkers that can be useful for risk stratification of patients with non-ischemic dilated cardiomyopathy.  相似文献   
82.
83.
84.
A novel autophagy inhibitor, autophazole (Atz), which promoted cancer cell death via caspase activation, is described. This compound was identified from cell-based high-content screening of an imidazole library. The results showed that Atz was internalized into lysosomes of cells where it induced lysosomal membrane permeabilization (LMP). This process generated nonfunctional autolysosomes, thereby inhibiting autophagy. In addition, Atz was found to promote LMP-mediated apoptosis. Specifically, LMP induced by Atz caused release of cathepsins from lysosomes into the cytosol. Cathepsins in the cytosol cleaved Bid to generate tBid, which subsequently activated Bax to induce mitochondrial outer membrane permeabilization (MOMP). This event led to cancer cell death via caspase activation. Overall, the findings suggest that Atz will serve as a new chemical probe in efforts aimed at gaining a better understanding of the autophagic process.  相似文献   
85.
NUMERICAL ANALYSES OF DESIGN AND ASSEMBLY FOR MAIN COMPONENTS OF BESIII   总被引:1,自引:0,他引:1  
The design and manufacture of the main drift chamber(MDC) and the electro-magnetic calorimeter are most important issues in Beijing electron-positron collider upgraded projects. The whole mass of electro-magnetic calorimeter (EMC) in BESIII is 40t, thus high stiffness, strength and dynamical properties are required for the design of entire structural of electro-magnetic calorimeter. Based on numerical technique, the strength and the dynamical properties of EMC are analyzed, which provide theoretical reference for the design of entire structural of EMC. The MDC is composed of the elements with 28680 pre-stressed high-sensitive wires and during the assembly the wires are stringed layer by layer. The stretching forces of the wires vary continuously and couple with each other in the whole process. The modeling technique with high precision (especially "element birth and death") is carefully used to study the stress state during the process of assembly. So the variations of the stretching force of the wire are investigated, and several design schemes are evaluated and optimized. The research results have been adopted in the Beijing electron-positron collider's new project directly.  相似文献   
86.
Colorectal cancer (CRC) is one of the most common malignancies worldwide with substantial mortality and morbidity. Alisertib (ALS) is a selective Aurora kinase A (AURKA) inhibitor with unclear effect and molecular interactome on CRC. This study aimed to evaluate the molecular interactome and anticancer effect of ALS and explore the underlying mechanisms in HT29 and Caco-2 cells. ALS markedly arrested cells in G2/M phase in both cell lines, accompanied by remarkable alterations in the expression level of key cell cycle regulators. ALS induced apoptosis in HT29 and Caco-2 cells through mitochondrial and death receptor pathways. ALS also induced autophagy in HT29 and Caco-2 cells, with the suppression of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR), but activation of 5′ AMP-activated protein kinase (AMPK) signaling pathways. There was a differential modulating effect of ALS on p38 MAPK signaling pathway in both cell lines. Moreover, induction or inhibition of autophagy modulated basal and ALS-induced apoptosis in both cell lines. ALS potently suppressed epithelial to mesenchymal transition (EMT) in HT29 and Caco-2 cells. Collectively, it suggests that induction of cell cycle arrest, promotion of apoptosis and autophagy, and suppression of EMT involving mitochondrial, death receptor, PI3K/Akt/mTOR, p38 MAPK, and AMPK signaling pathways contribute to the cancer cell killing effect of ALS on CRC cells.  相似文献   
87.
研究了一类杂化纠缠态在两种不同类型退相干信道下的纠缠动力学行为,以及退相干过程中出现的纠缠猝死现象.计算了相位阻尼信道和退极化信道下的纠缠度,并分析了纠缠度随时间的变化.结果表明在相位阻尼信道下不会出现纠缠猝死现象;在退极化信道下杂化纠缠态会经历纠缠猝死,纠缠度在某一特定的时间内衰减为零.  相似文献   
88.
陶瓷颗粒增强镍基合金复合材料是一种性能优良的复合材料,它能够将增强相和基体的性能相结合。应用细观力学和有限元理论将复合材料简化为含两个陶瓷颗粒的单胞,对材料单向拉伸下的应力场进行模拟,分析其应力的分布情况和复合材料的性能特征。结果表明,单胞中的应力是不均匀的,高刚度颗粒的界面附近应力最大并将首先破坏。最后利用单元消去技术模拟材料开裂情况下的应力场变化及裂纹扩展路径。研究对于理论分析和实验具有一定的参考和指导作用。  相似文献   
89.
These 2 studies explore the unconscious significance of death. 5 psychoanalytically oriented theories are discussed and used as the basis for scoring fantasy material. In the first study, 25 cancer patients and matched controls hospitalized for minor illnesses were given the TAT. Major findings for the dying patients point to (a) no increase in the use of denial, (b) an increase in themes of punishment, and (c) a rise in fantasies of illicit sexuality. The possibility is raised that death itself is sexualized and that this sexualization may at times increase, at other times decrease, death anxiety. In the second study, 25 women with a variety of serious illnesses and their controls were given selected TAT cards and new pictures. Results generally supported the prior findings. (25 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
90.
γ射线诱发细胞程序性死亡的时间及剂量效应研究   总被引:5,自引:0,他引:5  
通过对辐射所致程序性细胞死亡(PCD)的研究,揭示了射线诱发小鼠胸腺细胞PCD生成的时间及剂量效应规律,采用不同的检测PCD方法(DNA片段分析法及流式细胞术),比较了不同组织的辐射敏感性差异,结果表明,照射后4~6h诱发胸腺细胞PCD生成最多。不同剂量照射,照后6h取胸腺,发现20Gy时胸腺细胞PCD生成最多,脾,胸腺对辐射影响,小剂量(1Gy)即可检测PCD形成;而心脏,大脑,肾对射线不敏感,  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