全文获取类型
收费全文 | 2875篇 |
免费 | 88篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 57篇 |
综合类 | 2篇 |
化学工业 | 596篇 |
金属工艺 | 89篇 |
机械仪表 | 60篇 |
建筑科学 | 35篇 |
矿业工程 | 1篇 |
能源动力 | 165篇 |
轻工业 | 143篇 |
水利工程 | 22篇 |
石油天然气 | 17篇 |
无线电 | 335篇 |
一般工业技术 | 703篇 |
冶金工业 | 313篇 |
原子能技术 | 22篇 |
自动化技术 | 413篇 |
出版年
2023年 | 30篇 |
2022年 | 71篇 |
2021年 | 98篇 |
2020年 | 83篇 |
2019年 | 70篇 |
2018年 | 93篇 |
2017年 | 91篇 |
2016年 | 86篇 |
2015年 | 57篇 |
2014年 | 108篇 |
2013年 | 184篇 |
2012年 | 129篇 |
2011年 | 161篇 |
2010年 | 130篇 |
2009年 | 149篇 |
2008年 | 118篇 |
2007年 | 112篇 |
2006年 | 76篇 |
2005年 | 68篇 |
2004年 | 59篇 |
2003年 | 60篇 |
2002年 | 47篇 |
2001年 | 48篇 |
2000年 | 44篇 |
1999年 | 38篇 |
1998年 | 68篇 |
1997年 | 58篇 |
1996年 | 41篇 |
1995年 | 41篇 |
1994年 | 45篇 |
1993年 | 40篇 |
1992年 | 22篇 |
1991年 | 27篇 |
1990年 | 22篇 |
1989年 | 21篇 |
1988年 | 28篇 |
1987年 | 24篇 |
1986年 | 19篇 |
1985年 | 37篇 |
1984年 | 32篇 |
1983年 | 20篇 |
1982年 | 23篇 |
1981年 | 20篇 |
1980年 | 24篇 |
1979年 | 15篇 |
1978年 | 11篇 |
1977年 | 20篇 |
1976年 | 26篇 |
1975年 | 12篇 |
1973年 | 16篇 |
排序方式: 共有2973条查询结果,搜索用时 0 毫秒
81.
Sangita Kumari Karthikeyan Pillai Asha Sharma Ella Mihevc Amit Srivastava Albert Chan 《Particulate Science and Technology》2015,33(5):562-566
Cryogenic aerosol cleaning is a dry cleaning method used in the back end of line (BEOL) semiconductor manufacturing to remove defects from planar hydrophobic surfaces such as SiCOH and SiCxNyHz. Cryogenic aerosol cleaning is preferred over conventional wet cleaning methods as it is a non-contact cleaning method, which uses inert gases to generate sub-micrometer-sized solid aerosol particles that physically remove nanometer-sized contaminants on wafer surfaces. Particle removal mechanism involves detachment of the particles upon impact with aerosol, diffusion, and finally entrainment away from the wafer. In BEOL metal line patterning, particles on the dielectric isolation surfaces translate through the subsequent lithography and copper fill steps in to single or multiple metal line open defects that are yield killers. In this study, we show that the particle removal performance of the standard aerosol cleaning can be enhanced by pre-heating the wafer and use of a higher molecular weight inert gas, namely Ar, for aerosol generation. Both the addition of a Pre-heat step and the use of Ar as the aerosol source showed 47–52% reduction in single and multiple line opens detected through wafer electrical tests during high volume semiconductor manufacturing process. 相似文献
82.
83.
K.M. Gangotri Om Prakash Regar Chhagan Lal Prashant Kalla Kishna Ram Genwa Rajni Meena 《国际能源研究杂志》1996,20(7):581-585
Photogalvanic effects were studied in a photogalvanic cell containing toluidine blue, glucose and tergitol-7 as a photosensitizer, reductant and surfactant, respectively. The photocurrent and photopotential generated by this system were 70 μA and 315 mV, respectively. The effects of different parameters on the electrical output of the cell were observed. Current/voltage characteristics of the cell have also been studied, and a mechanism has been proposed for the generation of photocurrent in photogalvanic cell. 相似文献
84.
Anup Srivastava Thimmappa Shivanandappa 《Journal of the science of food and agriculture》2009,89(14):2461-2466
BACKGROUND: Roots of Decalepis hamiltonii are traditionally consumed as pickles and juice for their health benefits. We have earlier demonstrated the antioxidant property of the root extract and identified the constituent antioxidant molecules. RESULTS: This paper reports the effect of multiple‐dose (7, 15, and 30 days) treatment of Decalepis hamiltonii aqueous root extract (DHA) (50 and 100 mg kg?1 body weight) on the antioxidant profile of rat liver and brain. Activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione‐S‐transferase (GST) were increased and glutathione content was elevated in both liver and brain, apart from reduction in the basal level of lipid peroxidation. DHA induced stronger antioxidant boost in brain by increasing the activities of SOD, CAT, and GPx compared to liver. CONCLUSION: As failure to grapple with oxidative stress is an important factor in the etiology of several diseases, DHA's effects on improvement of antioxidant status could provide a scientific justification for the health‐promoting properties attributed to it. Copyright © 2009 Society of Chemical Industry 相似文献
85.
D. J. Davidson S. S. Sai Raman M. V. Lototsky O. N. Srivastava 《International Journal of Hydrogen Energy》2003,28(12):1425-1431
This paper deals with computer simulation of the P–C isotherms of some ZrFe2 type (Zr(Fe1−xCrx)2, Zr1−xTixFe1.4Cr0.6, Zr1−2xMmxTixFe1.4Cr0.6 : x00.4) of hydrogen storage materials. A feasible mathematical model has been developed to simulate the P–C isotherms. The randomized variables in the model applied for simulating the P–C isotherms of the above-mentioned ZrFe2 type hydrogen storage materials correspond to change in enthalpy (ΔH) and entropy (ΔS) of hydride formation. Several ZrFe2 type materials as in above have been synthesized and their P–C isotherms, enthalpy and entropy change has been evaluated experimentally in order to have input data for simulation. A special software was developed to simulate the P–C isotherms using the said model. A close match between the experimentally observed and simulated P–C isotherms for the above said ZrFe2 type alloys has been obtained. 相似文献
86.
The major objective of this study was to determine the fracture toughness and fracture surface energy of epoxy, epoxy/fly-ash, epoxy/carbon fibre, epoxy/carbon fibre/fly-ash, epoxy/glass fibre and epoxy/glass fibre/fly-ash composites. The quality of composite specimens was evaluated by the ultrasonic method. The results show that a fly-ash particle can arrest the crack path and thus improve the fracture properties of fibre reinforced plastic (FRP) composites. The results of this study have further significance in view of the fact that fly-ash powder is far cheaper than carbon fibre, glass fibre and epoxy resin. 相似文献
87.
Treatment of 6-O-p-tolylsulfonyl starch with anhydrous potassium fluoride in boiling 1,2-dihydroxyethane afforded deoxyfluorostarches (D. S. Fluorine 0.18). Reaction of starch with hydrofluoric acid in dimethyl sulfoxide at −30 °C gave deoxyfluorostarches of high fluorine content (D. S. Fluorine 0.91). Chlorodeoxystarches have been prepared by the reaction of corn starch with (chloromethylene) dimethylimminium chloride in N, N′-dimethyl-formamide. 相似文献
88.
Different synthetic products currently available and which find wide application as lubricants, are described, and their merits and demerits compared with the mineral based lubricants are outlined. Some of the major synthetic lubricants used in Indian industries are identified. The Indian chemical industry's potential to meet some of the requirements of synthetic lubricants is discussed and the need to create additional facilities in India for the manufacture of certain critical products, is described. 相似文献
89.
P. L. Soni H. W. Sharma S. S. Bisen H. C. Srivastava M. M. Gharia 《Starch - St?rke》1987,39(12):411-413
Starch from sal seeds cake was isolated, bleached and purified. Scanning electron microscopy of the starch showed round to oval shaped granules of the size 3.5 to 12.3 μm. The starch has more nitrogen, phosphorus, lipids, amylose and water binding capacity in comparison to the other starches of forest origin. Despite its low and seemingly restricted swelling, the sal starch is much more soluble at any particular degree of swelling. Paste viscosity curve showed no drop in viscosity after full gelatinisation had taken place, i. e. the paste is stable on continued cooking. 相似文献