全文获取类型
收费全文 | 2110篇 |
免费 | 49篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 21篇 |
综合类 | 2篇 |
化学工业 | 326篇 |
金属工艺 | 53篇 |
机械仪表 | 63篇 |
建筑科学 | 64篇 |
矿业工程 | 6篇 |
能源动力 | 58篇 |
轻工业 | 141篇 |
水利工程 | 18篇 |
石油天然气 | 15篇 |
无线电 | 222篇 |
一般工业技术 | 348篇 |
冶金工业 | 566篇 |
原子能技术 | 14篇 |
自动化技术 | 248篇 |
出版年
2022年 | 23篇 |
2021年 | 26篇 |
2020年 | 26篇 |
2019年 | 32篇 |
2018年 | 18篇 |
2017年 | 33篇 |
2016年 | 36篇 |
2015年 | 27篇 |
2014年 | 31篇 |
2013年 | 124篇 |
2012年 | 40篇 |
2011年 | 75篇 |
2010年 | 53篇 |
2009年 | 58篇 |
2008年 | 62篇 |
2007年 | 57篇 |
2006年 | 59篇 |
2005年 | 59篇 |
2004年 | 50篇 |
2003年 | 44篇 |
2002年 | 40篇 |
2001年 | 45篇 |
2000年 | 45篇 |
1999年 | 44篇 |
1998年 | 164篇 |
1997年 | 111篇 |
1996年 | 74篇 |
1995年 | 57篇 |
1994年 | 61篇 |
1993年 | 68篇 |
1992年 | 29篇 |
1991年 | 23篇 |
1990年 | 28篇 |
1989年 | 36篇 |
1988年 | 24篇 |
1987年 | 31篇 |
1986年 | 19篇 |
1985年 | 25篇 |
1984年 | 15篇 |
1983年 | 31篇 |
1982年 | 30篇 |
1981年 | 21篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 14篇 |
1977年 | 28篇 |
1976年 | 27篇 |
1974年 | 13篇 |
1973年 | 14篇 |
1972年 | 12篇 |
排序方式: 共有2165条查询结果,搜索用时 15 毫秒
1.
Darothi Bairagi Venkataramana Munukuti Pallabi Bhuyan Rajib Saha Sumantra Mandal 《工业材料与腐蚀》2021,72(5):829-838
The influence of cementite spheroidization on the impact toughness and electrochemical properties of a high-carbon steel has been thoroughly investigated in this study. Heavy warm rolling, followed by 2 h of annealing, has resulted in near-complete spheroidization, leading to a microstructure consisting of nano-cementite globules dispersed in the ultrafine-grained ferritic matrix. The Charpy impact test exhibited superior impact toughness with increased spheroidization. It is validated by the presence of abundant dimples in the fractographs of spheroidized specimens, in contrast to the as-received one that experienced a brittle failure due to its lamellar pearlitic structure. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) carried out in a 3.5% NaCl solution revealed that the corrosion resistance of the alloy gets improved with the increase in the degree of spheroidization. This is attributed to the lower susceptibility of the spheroidized specimen to microgalvanic corrosion owing to the minimum area of contact between nano-spheroidized cementite and ferrite, as elucidated with the help of EIS results aided by equivalent electrical circuit model. 相似文献
2.
Bioremediation by alkaline protease (AkP) from edible mushroom Termitomyces clypeatus: optimization approach based on statistical design and characterization for diverse applications
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
3.
van Schoor G. van Wyk J.D. Shaw I.S. 《Industrial Electronics, IEEE Transactions on》2003,50(3):546-553
A hybrid power compensator (HPC) consisting of a static VAr compensator and a dynamic compensator needs to be optimally controlled during the compensation of nonlinear loads. The HPC must be controlled to meet minimum requirements in terms of power factor and harmonic distortion, while at the same time minimizing its total cost. An artificial neural network (ANN) is used to control the HPC amidst a very dynamic power system environment. The performance of a reference ANN is evaluated while controlling an HPC connected to a typical nonlinear industrial load. The training and performance of the ANN is then optimized in terms of training set size, training set packing and ANN topology and the performance compared to the reference ANN. This paper highlights the importance of optimising the mentioned ANN parameters to achieve optimum ANN training and modeling accuracy. The results obtained reveals that the application of an ANN in controlling an HPC is feasible given that the ANN parameters are chosen appropriately. 相似文献
4.
ABSTRACT: Shellac and wax-based citrus coatings were applied to Fallglo, Robinson, Sunburst, Dancy and Murcott tangerines, Nova and Orlando tangelos, and Temple oranges. Flavor volatiles were measured before and after storage. Concentrations of ethyl acetate, ethyl butyrate, isopentanol and 2-methyl-3-buten-2-ol increased markedly for fruit with shellac-based coatings, and were highly correlated with ethanol content, but at different ratios for the different varieties. The concentration increases were relatively less for fruit coated with the wax-based coatings, and suggest that high-gloss shellac and resin-based coatings are not appropriate for tangerines. 相似文献
5.
6.
台北101层国际金融中心之结构施工技术与其设计考量概述 总被引:1,自引:0,他引:1
本文旨在简要说明目前正在施工中之超高层大楼—台北国际金融中心之结构系统、钢结构工程、钢筋混凝土工程基础与深开挖工程等特殊施工技术,并佐以相关之设计考量与施工规划概要,以供工程界做参考。 相似文献
7.
D. A. Morgan D. B. Shaw M. J. Sidebottom T. C. Soon R. S. Taylor 《Journal of the American Oil Chemists' Society》1985,62(2):292-299
The results presented in the literature, which attempt to elucidate the mechanisms by which triglyceride oils are bleached
by earths, are reviewed. The impact of this work and how the mechanistic proposals affect changes in oil properties are considered,
with particular emphasis on the needs of the palm oil processor. Important properties include color, metals and phosphorus
content and oxidative stability of the oil.
Investigations made in our own laboratories have been aimed at elucidating the effect of varying physical and chemical properties
of the bleaching earth on the quality of bleached and deodorized oils. Techniques used in this work are pore-size distribution,
surface area, scanning and transmission electron microscopy and a variety of chemical and X-ray analysis methods.
The ability to vary such parameters in montmorillonite clays by alteration of process conditions to give materials with specific
performance characteristics is demonstrated.
Comparisons are made between acid-activated montmorillonites and other clay types. 相似文献
8.
9.
10.
FM Scott AM Treston GL Shaw I Avis J Sorenson K Kelly EC Dempsey AB Cantor M Tockman JL Mulshine 《Canadian Metallurgical Quarterly》1996,14(2-3):239-251
Monitoring respiratory epithelial biology may reveal individuals with incipient lung cancer. The expression of neuroendocrine (NE) markers in pulmonary epithelium is thought to be central to lung development, repair of injury and may contribute to carcinogenesis. In this study, we evaluate several candidate NE markers to determine the feasibility of prospective analysis of clinical specimens. The potential NE markers include the enzyme L-DOPA decarboxylase (DDC), the neuropeptide gastrin releasing peptide (GRP), and peptidyl-glycine alpha-amidating monooxygenase (PAM), the bifunctional enzyme responsible for the final bioactivation step of many neuropeptides. A comparison of PAM activity and DDC levels in 30 lung cancer cell lines indicated that peptide amidating activity may be an indicator of NE status. Bronchoalveolar lavage (BAL) fluid from subjects at risk of developing second primary lung cancer and from volunteers was obtained. The activity of the first PAM enzyme, peptidylglycine alpha-hydroxylating monooxygenase (PHM), ranged from not detectable to 507 pmol/h/mg protein in 57 specimens. The second PAM enzyme, peptidylamidoglycolate lyase (PAL), ranged from not detectable to 414 pmol/h/mg protein in 56 specimens. Using cluster analysis by the average linkage method, a group of enzyme values with PHM greater than 230 pmol/h/mg protein was determined. Long-term follow-up of these patients for new second primary lung cancers may help to determine the potential predictive value of PAM detected in the BAL fluid. 相似文献