全文获取类型
收费全文 | 168542篇 |
免费 | 1200篇 |
国内免费 | 186篇 |
专业分类
电工技术 | 2556篇 |
综合类 | 121篇 |
化学工业 | 26616篇 |
金属工艺 | 9472篇 |
机械仪表 | 5715篇 |
建筑科学 | 3008篇 |
矿业工程 | 1887篇 |
能源动力 | 2706篇 |
轻工业 | 8815篇 |
水利工程 | 2742篇 |
石油天然气 | 8694篇 |
武器工业 | 12篇 |
无线电 | 14494篇 |
一般工业技术 | 38257篇 |
冶金工业 | 27795篇 |
原子能技术 | 6936篇 |
自动化技术 | 10102篇 |
出版年
2018年 | 2979篇 |
2017年 | 3091篇 |
2016年 | 3346篇 |
2015年 | 1682篇 |
2014年 | 2957篇 |
2013年 | 6338篇 |
2012年 | 4311篇 |
2011年 | 5397篇 |
2010年 | 4420篇 |
2009年 | 4894篇 |
2008年 | 4940篇 |
2007年 | 4868篇 |
2006年 | 4141篇 |
2005年 | 3819篇 |
2004年 | 3634篇 |
2003年 | 3520篇 |
2002年 | 3450篇 |
2001年 | 3463篇 |
2000年 | 3362篇 |
1999年 | 3213篇 |
1998年 | 7018篇 |
1997年 | 5149篇 |
1996年 | 3821篇 |
1995年 | 2917篇 |
1994年 | 2594篇 |
1993年 | 2720篇 |
1992年 | 2254篇 |
1991年 | 2304篇 |
1990年 | 2409篇 |
1989年 | 2316篇 |
1988年 | 2314篇 |
1987年 | 2191篇 |
1986年 | 2246篇 |
1985年 | 2292篇 |
1984年 | 2206篇 |
1983年 | 2135篇 |
1982年 | 1980篇 |
1981年 | 2193篇 |
1980年 | 2054篇 |
1979年 | 2269篇 |
1978年 | 2431篇 |
1977年 | 2430篇 |
1976年 | 3095篇 |
1975年 | 2244篇 |
1974年 | 2307篇 |
1973年 | 2342篇 |
1972年 | 2155篇 |
1971年 | 1911篇 |
1970年 | 1701篇 |
1969年 | 1632篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Kosmatski Ya. I. Fokin N. V. Barichko B. V. Yakovleva K. Yu. Nikolenko V. D. 《Metallurgist》2021,65(7-8):713-721
Metallurgist - The article presents the results of plastometric studies on hot deformation and studies on the hardening curves in cold deformation of EP450-Sh (12H12M1BFR-Sh) and EP823-Sh... 相似文献
62.
Metallurgist - The article provides a brief assessment of the current state of power supply units at metallurgical plants and prospects for their future development. The principal power-supply... 相似文献
63.
Metallurgist - The well-known technologies of remelting iron shavings lead to significant (30%) losses of metal. An electroslag smelting furnace with graphite electrodes is proposed for remelting... 相似文献
64.
Baranov D. A. Zhatkin S. S. Nikitin V. I. Deev V. B. Nikitin K. V. Barinov A. Yu. Yudin D. M. 《Russian Journal of Non-Ferrous Metals》2021,62(4):441-447
Russian Journal of Non-Ferrous Metals - The process of making a weld using the heat-resistant EP693 alloy (Ni–Cr–W–Co–Co–Mo system) to make assemblies and components... 相似文献
65.
Demirov A. P. Blinkov I. V. Kuznetsov D. V. Kuskov K. V. Kolesnikov E. A. Sedegov A. S. 《Russian Journal of Non-Ferrous Metals》2021,62(5):602-610
Russian Journal of Non-Ferrous Metals - This article discusses methods for producing a material with gradient multilevel porosity by sintering layer-by-layer distributed α-Fe2O3 nanopowders... 相似文献
66.
Lysunenko N.O. Brodnikovskyi Y.M. Mokiichuk V.M. Polishko I.O. Brodnikovskyi D.M. Chedryk V.I. Vasylyev O.D. 《Powder Metallurgy and Metal Ceramics》2021,60(5-6):352-359
Powder Metallurgy and Metal Ceramics - Fuel cells are today among the most efficient and environmentally friendly devices for the production of electricity. They are developing rapidly and are... 相似文献
67.
68.
H.J.C. Weighell Wh. Sch. C.Eng. M.I.M.E. M.I.P.E. 《The International journal of environmental studies》2013,70(1-4):237-242
Vehicle legislation for safety and emission control is led by the USA where half the world's cars and one‐third of the world's road deaths are found. The 1975/6 standards will cause confrontations between industry and government in the U.S.A. and have costly implications for the American people. The rest of the world is affected by what happens in the U.S.A. but for language and other reasons fragmented laws are normal with conflicting requirements for manufacturers who supply the many markets. The greatest force for harmonization of legislation may be the enlarged Common Market including, as it does, the four major European Car manufacturing countries. The Common Market Commission may displace WP 29 of the United Nations as the leading law‐making body. Type approval is the compliance system used in Europe, but the growth in scope of safety and other legislation is bringing into focus a weakness of the system which is reducing production efficiency to an alarming degree. American style self‐certification is not acceptable to European governments. 相似文献
69.
I.P.L. Coleman J.A. Blair M.E. Hilburn 《The International journal of environmental studies》2013,70(3-4):187-191
The effect of a number of dietary and synthetic chelating agents on the intestinal absorption of lead has been examined using the everted sac preparation and the tracer isotope 203Pb. All the agents examined increased lead transport into the serosal compartment. An explanation of the way in which these agents modify the model to describe lead transport is proposed. 相似文献
70.
Large‐span reinforced concrete (RC) shells collapses that occurred in the last decade caused many death toll as well as significant losses to national economies. The most famous cases were the collapse of the aqua park cover in Moscow on February 2004 and the 2E terminal roof destruction at Charles de Gaulle Airport near Paris on May 2004. Following the publications of the appropriate commissions that have studied the reasons of these events, the influence of concrete creep and changes in the shell geometry on buckling of RC thin‐walled shells was not properly considered in the design. This study is focused on buckling of such shells, taking into account geometrical and physical nonlinear behaviour of compressed concrete. Other important reasons of concrete shells collapse are also analysed. The study is based on available experimental and theoretical investigations of ferro‐cement shells' models previously performed by the first author. The results of these investigations, obtained for small‐scale ferro‐cement models of thin‐walled shallow RC shells, are discussed. Behaviour of the tested models is compared with that of the above‐mentioned real shells and similar structures, which also collapsed. The critical buckling loads for the shells are obtained. It is shown that these loads are lower than the actual ones; thus, the shells buckling was unavoidable. To prevent brittle shell failure, they should be designed using other dominant failure modes that appear before the buckling. Possible failure schemes of real RC shells can be predicted using dominant failure modes obtained by laboratory testing of scaled models. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献