全文获取类型
收费全文 | 403914篇 |
免费 | 4765篇 |
国内免费 | 1341篇 |
专业分类
电工技术 | 7591篇 |
综合类 | 321篇 |
化学工业 | 59860篇 |
金属工艺 | 16427篇 |
机械仪表 | 13488篇 |
建筑科学 | 8357篇 |
矿业工程 | 2154篇 |
能源动力 | 11532篇 |
轻工业 | 28489篇 |
水利工程 | 4273篇 |
石油天然气 | 7916篇 |
武器工业 | 17篇 |
无线电 | 49267篇 |
一般工业技术 | 83022篇 |
冶金工业 | 74960篇 |
原子能技术 | 9193篇 |
自动化技术 | 33153篇 |
出版年
2022年 | 2561篇 |
2021年 | 3888篇 |
2020年 | 2972篇 |
2019年 | 3809篇 |
2018年 | 6490篇 |
2017年 | 6487篇 |
2016年 | 6932篇 |
2015年 | 4322篇 |
2014年 | 7144篇 |
2013年 | 20033篇 |
2012年 | 11418篇 |
2011年 | 15276篇 |
2010年 | 12152篇 |
2009年 | 13718篇 |
2008年 | 14052篇 |
2007年 | 13820篇 |
2006年 | 12416篇 |
2005年 | 11112篇 |
2004年 | 10506篇 |
2003年 | 10417篇 |
2002年 | 9829篇 |
2001年 | 9733篇 |
2000年 | 9133篇 |
1999年 | 9522篇 |
1998年 | 24328篇 |
1997年 | 16708篇 |
1996年 | 12797篇 |
1995年 | 9517篇 |
1994年 | 8362篇 |
1993年 | 8379篇 |
1992年 | 6055篇 |
1991年 | 5695篇 |
1990年 | 5679篇 |
1989年 | 5318篇 |
1988年 | 5043篇 |
1987年 | 4420篇 |
1986年 | 4299篇 |
1985年 | 4812篇 |
1984年 | 4422篇 |
1983年 | 3994篇 |
1982年 | 3654篇 |
1981年 | 3730篇 |
1980年 | 3435篇 |
1979年 | 3326篇 |
1978年 | 3334篇 |
1977年 | 3750篇 |
1976年 | 4847篇 |
1975年 | 2850篇 |
1974年 | 2663篇 |
1973年 | 2730篇 |
排序方式: 共有10000条查询结果,搜索用时 119 毫秒
131.
S. A. Selishcheva M. Yu. Lebedev S. I. Reshetnikov L. I. Trusov V. A. Yakovlev 《Catalysis in Industry》2014,6(1):60-66
To establish principal regularities of the hydrotreatment of rapeseed oil fatty acid triglycerides (FATs), the kinetics of this process has been studied at temperatures of 300–380°C, contact times of 0.38–0.10 h, and a hydrogen pressure of 1.0 MPa in a flow fixed-bed reactor. The process is performed over nonsulfided nickel catalysts, which are of great practical interest for the production of green diesel. The kinetic scheme of the process with consideration for target products (alkanes) and all oxygen-containing by-products has been proposed. The quantitative estimate, which enables the prediction of the composition of products for other process conditions, has been obtained for the principal paths of the hydrotreatment of rapeseed oil FATs. 相似文献
132.
I.?I.?SalakhovEmail author A.?Z.?Batyrshin S.?A.?Sergeev G.?D.?Bukatov A.?A.?Barabanov A.?G.?Sakhabutdinov V.?A.?Zakharov Kh.?Kh.?Gilmanov 《Catalysis in Industry》2014,6(3):198-201
A comparative study of propylene polymerization in liquid monomer is performed under laboratory conditions using the IK-8-21 Ti-Mg catalyst designed at the Boreskov Institute of Catalysis and imported industrial catalysts (conditionally labeled TMC-1, -2, and -3). The activity and stereospecificity of the catalysts are estimated along with properties of the resulting polypropylene (granular composition and physicomechanical characteristics). It is shown that the IK-8-21 catalyst is not inferior to imported counterparts in terms of catalytic properties in the synthesis of polypropylene. The polypropylene powder formed on IK-8-21 is homogeneous and has good morphology. The physicomechanical characteristics of polypropylene synthesized on the domestic IK-8-21 catalyst are similar to those for polypropylene prepared with the imported TMK-1 catalyst. 相似文献
133.
134.
Shaldaev V. S. Malofeeva A. N. Davydov A. D. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(1):136-141
Protection of Metals and Physical Chemistry of Surfaces - Pitting formation in carbon steel in saturated Ca(OH)2 solutions containing different concentrations of added NaCl is studied... 相似文献
135.
Drozdov V. A. Pyanova L. G. Lavrenov A. V. Likholobov V. A. Kudrya E. N. Luzyanina L. S. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(6):1035-1043
Protection of Metals and Physical Chemistry of Surfaces - A method for introducing small amounts of betulin (up to 1 wt %) into a mesoporous carbon material with a preset specific surface area of... 相似文献
136.
Emel’yanov A. S. Rodin A. V. Belova E. V. Vidanov V. L. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(6):1044-1049
Protection of Metals and Physical Chemistry of Surfaces - The thermal stability of KU-2*8 cation exchanger mixed with 4 and 12 mol/L nitric acids is studied via differential scanning calorimetry... 相似文献
137.
Rudnev V. S. Lukiyanchuk I. V. Vasilyeva M. S. Zvereva A. A. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(4):719-728
Protection of Metals and Physical Chemistry of Surfaces - The effect of the temperature of annealing in air on the surface architecture and composition of oxide layers has been studied.... 相似文献
138.
Leonova A. A. Ayupov A. B. Mel’gunov M. S. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(2):316-320
Protection of Metals and Physical Chemistry of Surfaces - By means of elemental and X-ray powder diffraction analysis, N2 adsorption at –196°C and CO2 adsorption at 0°C the textural... 相似文献
139.
Raja S.R.Gajjela Arthur L.Hendriks James O.Douglas Elisa M.Sala Petr Steindl Petr Klenovsky Paul A.J.Bagot Michael P.Moody Dieter Bimberg Paul M.Koenraad 《光:科学与应用(英文版)》2021,10(7):1313-1325
We investigated metal-organic vapor phase epitaxy grown (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots (QDs) with potential applications in QD-Flash memo... 相似文献
140.
R. Satheeskumar Bonam Raghavaiah S. Geerthik T. Senthil Kumar 《Concurrency and Computation》2024,36(1):e7873
This article proposes a high efficiency video coding (HEVC) standard hardware using block matching motion estimation algorithm. A hybrid parallel spiral and adaptive threshold star diamond search algorithm (Hyb PS-ATSDSA) proposes for fast motion estimation in HEVC. Parallel spiral search approach utilizes spiral pattern for searching from center to the surroundings and adaptive threshold SDA consists of two phases, they are adaptive threshold and star diamond algorithm. To lower computational complexities in HEVC architecture, parallel spiral search algorithm uses several blocks matching schemes. Adaptive threshold and star diamond algorithm are used to reduce the matching errors and remove the invalid blocks early from the procedure of motion estimation and finally predicts the final motion of the image. Speed is increased while using this hybrid algorithm. Proposed structure is carried out in Xilinx; ISE 14.5 design suit, then the experimental outcomes are analyzed to existing motion estimation strategies in field-programmable gate array devices. Experimental performance of the proposed Hyb-PS-ATSDSA-ME-HEVC method attains lower delay 33.97%, 32.97%, 62.97, and 26.97%, and lower area 34.867%, 45.97%, 27.97%, and 43.967% compared with the existing methods, such as FSA-ME-HEVC, TZSA-ME-HEVC, hyb TZSA-IME-HEVC, and IBMSA-ME-HEVC, respectively. 相似文献