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   1000篇
  免费   33篇
  国内免费   1篇
电工技术   6篇
综合类   1篇
化学工业   137篇
金属工艺   11篇
机械仪表   64篇
建筑科学   29篇
矿业工程   2篇
能源动力   31篇
轻工业   129篇
水利工程   12篇
石油天然气   2篇
武器工业   2篇
无线电   115篇
一般工业技术   122篇
冶金工业   249篇
原子能技术   2篇
自动化技术   120篇
  2022年   10篇
  2021年   16篇
  2020年   19篇
  2019年   22篇
  2018年   28篇
  2017年   29篇
  2016年   21篇
  2015年   11篇
  2014年   31篇
  2013年   47篇
  2012年   42篇
  2011年   34篇
  2010年   35篇
  2009年   35篇
  2008年   53篇
  2007年   44篇
  2006年   28篇
  2005年   26篇
  2004年   25篇
  2003年   19篇
  2002年   22篇
  2001年   18篇
  2000年   17篇
  1999年   9篇
  1998年   44篇
  1997年   34篇
  1996年   30篇
  1995年   15篇
  1994年   21篇
  1993年   15篇
  1992年   12篇
  1991年   9篇
  1990年   18篇
  1989年   13篇
  1988年   9篇
  1987年   7篇
  1986年   10篇
  1985年   11篇
  1984年   13篇
  1983年   14篇
  1982年   11篇
  1981年   18篇
  1980年   13篇
  1979年   7篇
  1978年   8篇
  1977年   11篇
  1976年   16篇
  1972年   6篇
  1970年   4篇
  1969年   5篇
排序方式: 共有1034条查询结果,搜索用时 265 毫秒
1.
Wireless Personal Communications - Today’s high speed data processing and memory storage operations demand immediate data write and retrieval to meet up to benchmark. To act as a volatile or...  相似文献   
2.
Each year, thousands of patients die from antimicrobial‐resistant bacterial infections that fail to respond to conventional antibiotic treatment. Antimicrobial polymers are a promising new method of combating antibiotic‐resistant bacterial infections. We have previously reported the synthesis of a series of narrow‐spectrum peptidomimetic antimicrobial polyurethanes that are effective against Gram‐negative bacteria, such as Escherichia coli; however, these polymers are not effective against Gram‐positive bacteria, such as Staphylococcus aureus. With the aim of understanding the correlation between chemical structure and antibacterial activity, we have subsequently developed three structural variants of these antimicrobial polyurethanes using post‐polymerization modification with decanoic acid and oleic acid. Our results show that such modifications converted the narrow‐spectrum antibacterial activity of these polymers into broad‐spectrum activity against Gram‐positive species such as S. aureus, however, also increasing their toxicity to mammalian cells. Mechanistic studies of bacterial membrane disruption illustrate the differences in antibacterial action between the various polymers. The results demonstrate the challenge of balancing antimicrobial activity and mammalian cell compatibility in the design of antimicrobial polymer compositions. © 2019 Society of Chemical Industry  相似文献   
3.
Pattern Analysis and Applications - Action recognition is an active research area in computer vision as it has enormous applications in today’s world, out of which, recognizing violent action...  相似文献   
4.
Cardiovascular disease is the leading cause of death in the United States, accounting for nearly one in every seven deaths. Over the last decade, various targeted therapeutics have been introduced, but there has been no corresponding improvement in patient survival. Since the mortality rate of cardiovascular disease has not been significantly decreased, efforts have been made to understand the link between heart disease and novel therapeutic targets such as non-coding RNAs. Among multiple non-coding RNAs, long non-coding RNA (lncRNA) has emerged as a novel therapeutic in cardiovascular medicine. LncRNAs are endogenous RNAs that contain over 200 nucleotides and regulate gene expression. Recent studies suggest critical roles of lncRNAs in modulating the initiation and progression of cardiovascular diseases. For example, aberrant lncRNA expression has been associated with the pathogenesis of ischemic heart failure. In this article, we present a synopsis of recent discoveries that link the roles and molecular interactions of lncRNAs to cardiovascular diseases. Moreover, we describe the prevalence of circulating lncRNAs and assess their potential utilities as biomarkers for diagnosis and prognosis of heart disease.  相似文献   
5.
6.
The work reported involved the fabrication of an electrospun tubular conduit of a gelatin and polycaprolactone (PCL) blend as an adventitia‐equivalent construct. Gelatin was included as the matrix for increased biocompatibility with the addition of PCL for durability. This is contrary to most of the literature available for biomaterials based on blends of gelatin and PCL where PCL is the major matrix. The work includes the assiduous selection of key electrospinning parameters to obtain smooth bead‐free fibres with a narrow distribution of pore size and fibre diameter. Few reports elucidate the optimization of all electrospinning parameters to fabricate tubular conduits with a focus on obtaining homogeneous pores and fibres. This stepwise investigation would be unique for the fabrication of gelatin–PCL electrospun tubular constructs. The fabricated microfibrous gelatin–PCL constructs had pores of size ca 50–100 μm reportedly conducive for cell infiltration. The measured value of surface roughness of 57.99 ± 17.4 nm is reported to be favourable for protein adhesion and cell adhesion. The elastic modulus was observed to be similar to that of the tunica adventitia of the native artery. Preliminary in vitro and in vivo biocompatibility tests suggest safe applicability as a biomaterial. Minimal cytotoxicity was observed using MTT assay. Subcutaneous implantation of the scaffold demonstrated acute inflammation which decreased by day 15. The findings of this study could enable the fabrication of smooth bead‐free microfibrous gelatin–PCL tubular construct as viable biomaterial which can be included in a bilayer or a trilayer scaffold for vascular tissue engineering. © 2019 Society of Chemical Industry  相似文献   
7.
8.
Hydroxyapatite has been synthesized using eggshell membrane as bio-template along with the assistance of microwave heating. Eggshell membrane is infiltrated with calcium and phosphorous precursors before heating it in a domestic microwave oven. Hydroxyapatite formed retained the interwoven hierarchical structure of the eggshell membrane. Structural analysis was performed using X-ray diffraction, and the microstructural features are characterized by scanning electron microscopy. Distinct morphological features were present in microwave processed hydroxyapatite when compared to the conventionally processed one. Transmission electron microscopic investigations and BET surface area analysis were also carried out.  相似文献   
9.
The health impact of indoor air pollution in informal settlement households has not been extensively studied in South Africa. This cross‐sectional study investigated the association between asthma and common indoor exposures among schoolchildren from four informal settlements located in two municipalities in the Western Cape Province. A total of 590 children, aged 9‐11 years, were recruited. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was administered to caregivers. Pulmonary function assessment included spirometry and fractional exhaled nitric oxide (FeNO). Phadiatop test for atopy was done. The prevalence of doctor‐diagnosed asthma was 3.4% (n = 20) among whom only 50% were on treatment. The prevalence of current wheeze was 12.9%, and 17.6% had airway obstruction (FEV1 < lower limit of normal), while 10.2% had airway inflammation (FeNO > 35 ppb). In adjusted logistic regression models, dampness, visible mold growth, paraffin use for cooking, and passive smoking were associated with a twofold to threefold increased risk in upper and lower airway outcomes. The strongest association was that of visible mold growth with rhinitis (adjusted odds ratio—aOR 3.37, 95% CI: 1.69‐6.71). Thus, there is a need for improved diagnosis of childhood asthma and Indoor Air Quality in informal settlement households.  相似文献   
10.
Universal Access in the Information Society - Lack of Sign Language-based learning tools is a hindrance in acquiring knowledge for deaf students. Technology-based tools have introduced innovative...  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