全文获取类型
收费全文 | 3012篇 |
免费 | 17篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 185篇 |
金属工艺 | 23篇 |
机械仪表 | 16篇 |
建筑科学 | 21篇 |
能源动力 | 47篇 |
轻工业 | 43篇 |
水利工程 | 11篇 |
石油天然气 | 7篇 |
无线电 | 65篇 |
一般工业技术 | 162篇 |
冶金工业 | 2400篇 |
原子能技术 | 11篇 |
自动化技术 | 35篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 20篇 |
2020年 | 17篇 |
2019年 | 10篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 25篇 |
2015年 | 17篇 |
2014年 | 28篇 |
2013年 | 37篇 |
2012年 | 34篇 |
2011年 | 66篇 |
2010年 | 62篇 |
2009年 | 22篇 |
2008年 | 37篇 |
2007年 | 31篇 |
2006年 | 22篇 |
2005年 | 10篇 |
2004年 | 12篇 |
2003年 | 15篇 |
2002年 | 12篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 67篇 |
1998年 | 685篇 |
1997年 | 375篇 |
1996年 | 263篇 |
1995年 | 146篇 |
1994年 | 118篇 |
1993年 | 164篇 |
1992年 | 37篇 |
1991年 | 28篇 |
1990年 | 25篇 |
1989年 | 38篇 |
1988年 | 41篇 |
1987年 | 40篇 |
1986年 | 34篇 |
1985年 | 42篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 29篇 |
1978年 | 12篇 |
1977年 | 70篇 |
1976年 | 198篇 |
1975年 | 8篇 |
1955年 | 2篇 |
排序方式: 共有3031条查询结果,搜索用时 15 毫秒
101.
Conjugated linoleic acid, a fatty acid found in milk fat and ruminant meat is one of the functional food components. Modifying fatty acid composition so as to increase CLA and other beneficial PUFA/MUFA level and reducing SFA levels might be a key to enhance the neutraceutical and therapeutic value of ruminant-derived food products. In the present experiment, the effect of supplementation of polyphenol rich Terminalia chebula plant extract at different concentrations (1.06 g/kg and 3.18 g/kg of body weight in T1 and T2 groups, respectively) was investigated on fatty acid composition of rumen fluid, plasma, intramuscular fat and Δ9-desaturase activity in longissimus dorsi muscle of crossbred kids. Total MUFA and PUFA content in muscle were enhanced by 25 and 35%, respectively, whereas SFA was reduced by 20% thereby improving the desaturation index. Δ9-desaturase activity also increased by 47% resulting in an enhancement of total CLA content (58.73%) in muscle. 相似文献
102.
103.
105.
106.
Electrochemical oxidation of Inosine has been studied in the phosphate buffers of pH range 3.3-10.9 at pyrolytic graphite electrode. In the entire pH range a single well-defined oxidation peak (Ia) was observed, when the sweep was initiated in the positive direction. In the reverse sweep no cathodic peak was obtained. The peak potential of the oxidation peak was dependent on pH and shifted to less positive potential with increase in pH. The kinetics of the UV absorbing intermediate was followed spectrophotometrically and the decay occurred in a pseudo first order reaction having k values in the range 0.50-0.92 × 10−3 s−1 in the entire pH range studied. The value of n was found to be 2.95 ± 0.3. The products of oxidation were silylated and characterized by using GC-Mass. Two tetramers having CC, CN, NN, CON and COOC linkages were identified. A plausible mechanism for the electrooxidation of Inosine has been suggested. 相似文献
107.
Sathi Rajachandran Nair Ram Dayal Purohit Avesh Kumar Tyagi Pankaj Kumar Sinha Beant Prakash Sharma 《Journal of the American Ceramic Society》2008,91(1):88-91
Ultrafine La(Ca)CrO3 (LCC) powder was prepared through the glycine–nitrate gel combustion process. It was shown for the first time that the use of relatively inexpensive CrO3 as a starting material for chromium has potential for the bulk preparation of sinter-active LCC powder. As-prepared powder, when calcined at 700°C, resulted in LCC along with a small amount of CaCrO4 . The calcined powder was found to be composed of soft agglomerates with a particle size of ≈70–290 nm. The cold pressing and sintering of the calcined powder at 1200°C resulted in the mono-phasic La0.7 Ca0.3 CrO3 with density ≈98% of its theoretical value. This is the lowest sintering temperature ever reported for La0.7 Ca0.3 CrO3 . The conductivity of the sintered La0.7 Ca0.3 CrO3 at 1000°C was found to be ≈57 S/cm in air. The sintering and electrical behavior achieved for La0.7 Ca0.3 CrO3 may find application as an interconnect material for high-temperature solid oxide fuel cells if problems with chemical expansion and poor conductivity in fuel can be overcome. 相似文献
108.
109.
110.
Nowadays, energy is key consideration in discussions of sustainable development. So, sustainable development requires a sustainable supply of clean and affordable renewable energy sources that do not cause negative societal impacts. Energy sources such as solar radiation, the winds, waves and tides are generally considered renewable and, therefore, sustainable over the relatively long term. Wastes and biomass fuels are usually viewed as sustainable energy sources. Wastes are convertible to useful energy forms like hydrogen (biohydrogen), biogas, bioalcohol, etc., through waste-to-energy technologies.In this article, possible future energy utilization patterns and related environmental impacts, potential solutions to current environmental problems and renewable energy technologies and their relation to sustainable development are discussed with great emphasis on waste-to-energy routes (WTERs). 相似文献