全文获取类型
收费全文 | 429篇 |
免费 | 15篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 74篇 |
金属工艺 | 17篇 |
机械仪表 | 28篇 |
建筑科学 | 5篇 |
能源动力 | 23篇 |
轻工业 | 30篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 77篇 |
一般工业技术 | 97篇 |
冶金工业 | 61篇 |
原子能技术 | 3篇 |
自动化技术 | 24篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 15篇 |
2020年 | 11篇 |
2019年 | 8篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 18篇 |
2013年 | 26篇 |
2012年 | 19篇 |
2011年 | 16篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 13篇 |
1999年 | 5篇 |
1998年 | 24篇 |
1997年 | 10篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有444条查询结果,搜索用时 140 毫秒
21.
ABSTRACT De-ashing of Indian coal samples from Bhojudih, Mandaman and Kusumunda has been studied using High Gradient Magnetic Separation (HGMS(. Coating of the ash particles with magnetite or blue dust brings down the operating magnetic field considerably. The flow velocity has a significant effect on the removal as well as Heat Value Recovery (HVR). 相似文献
22.
Ultraviolet absorption spectroscopy, has an immense potential for characterization of aromatic hydrocarbons in distillate petroleum fractions. The second derivative ultraviolet spectroscopy has improved the understanding of complex aromatic structures, such as polynuclear aromatics, which are present in gas oil fractions. Normal and second derivative ultraviolet spectroscopy of gas oils and their separated fractions are discussed in detail and conclusions are drawn regarding mono-di-and polynuclear aromatics in various gas oils. 相似文献
23.
Mangalvedekar H.A. Paithankar A.S. Chakravarthy D.P. Dixit K.P. Barve D.N. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2009,16(4):1006-1010
This paper discusses the experiments conducted for the development of 50 kV, 10 A, 10 μs duration, and rise time of 2 μs solid state pulse power modulator using toroidal amorphous steel core and low cost IGBT switches. The experiments revealed (i) the need for new design methodologies based on energy transfer between the electrical and magnetic systems and (ii) the success of low-cost switching circuit. 相似文献
24.
The application of electrogenerated iodonium ion, acting as catalytic electron carrier, has been taken into account in the intramolecular oxidative cyclization reaction of 2-nitroaniline on graphite anode in the preparation of benzofuroxan, which is of great synthetic utility. 相似文献
25.
Anupam Dikshit N.K. Dubey N.N. Tripathi S.N. Dixit 《Journal of Stored Products Research》1983,19(4):159-162
Seeds of two spices Coriandrum sativum and Foeniculum vulgare, were dressed separately with essential oil of Cedrus deodara as well as with five synthetic fungicides viz., phenylmercury acetate, 2-methoxyethyl mercury chloride, copper oxychloride, mancozeb and wettable sulphur. Treated seeds were stored in polythene bags for 12 months. On mycofloral analysis, the oil had checked the appearance of ten fungi, Absidia sp., Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. ruber, A. versicolor, Cladosporium cladosporioides, Curvularia lunata, and Paecilomyces variotii on the seeds of C. sativum, and seven fungi, Absidia sp., A. flavus, A. fumigatus, A. niger, A. ruber, A. versicolor, and Rhizopus spp., on the seeds of F. vulgare. The oil proved to be more effective than the synthetic fungicides. Further, the oil did not show any adverse effect on seed germination and seedling growth of both spices. 相似文献
26.
27.
28.
Enhancement in electrical and magnetodielectric properties of Ca‐ and Ba‐doped BiFeO3 polycrystalline ceramics 下载免费PDF全文
Ramachandran Balakrishnan Ambesh Dixit Ratna Naik Mamidanna Sri Ramachandra Rao 《Journal of the American Ceramic Society》2018,101(2):782-788
We carried out a comparative study on the electrical and magnetodielectric properties of polycrystalline BiFeO3, Bi0.9Ca0.1FeO2.95, Bi0.9Ba0.05Ca0.05FeO2.95, and Bi0.9Ba0.1FeO2.95 ceramics. The two dielectric anomalies, near 25 K and 281 K, are observed for BiFeO3. Interestingly, the anomaly near 25 K shifts towards a higher temperature above 60 K with Ca and/or Ba doping, attributed to the doping induced chemical pressure. In addition, the room temperature switchable magnetodielectric effect is witnessed for the doped BiFeO3 compounds, due to the quadratic magnetoelectric coupling. This indicates the improved magnetoelectric coupling in BiFeO3 with the Ca and Ba doping. This is essentially due to the enhanced magnetic ordering and reduced leakage current in BiFeO3 after the doping. 相似文献
29.
The use of separate transport and economic models in urban planning provides a limited view of economic impacts, restricts the testing of network design options and lengthens the planning process. Furthermore, the standard methodology for economic appraisal assumes partial economic equilibrium and cannot determine the distribution of impacts from the transport sector to households. Computable general equilibrium (CGE) models can capture general equilibrium effects and measure welfare at the household level, but mostly lack integration with transport models and do not represent all trip generators. This paper develops an integrated traffic assignment and spatial CGE model in nonlinear complementarity form, casted as a framework for economic appraisal of urban transport projects. The CGE submodel generates commuting, shopping and leisure trips as inputs into the transport submodel, which then assigns trips to the network according to user equilibrium. The resulting travel times then feed back into household prices and freight margins. Households and firms fully account for travel times in decisions on where to shop, how much labour to supply and where to source production inputs. Calibration and applications of the model are demonstrated for 14 regions and 2 industries across Sydney using GAMS/PATH on the NEOS server. The welfare of various network improvements is measured using equivalent variations. The model can be calibrated to external strategic transport models, and be extended to simulate additional trip generators and land-use. 相似文献
30.
Multimedia Tools and Applications - Heart disease patients are continuously increasing. The patients face the problem of a delayed diagnosis as the subjects do not undergo routine tests and consult... 相似文献