全文获取类型
收费全文 | 365336篇 |
免费 | 46010篇 |
国内免费 | 32172篇 |
专业分类
电工技术 | 27231篇 |
技术理论 | 10篇 |
综合类 | 26862篇 |
化学工业 | 88598篇 |
金属工艺 | 13703篇 |
机械仪表 | 20469篇 |
建筑科学 | 20622篇 |
矿业工程 | 7405篇 |
能源动力 | 10336篇 |
轻工业 | 38889篇 |
水利工程 | 6067篇 |
石油天然气 | 13769篇 |
武器工业 | 3670篇 |
无线电 | 44184篇 |
一般工业技术 | 40238篇 |
冶金工业 | 10152篇 |
原子能技术 | 4524篇 |
自动化技术 | 66789篇 |
出版年
2024年 | 1295篇 |
2023年 | 5897篇 |
2022年 | 10183篇 |
2021年 | 14886篇 |
2020年 | 12522篇 |
2019年 | 11671篇 |
2018年 | 10955篇 |
2017年 | 14502篇 |
2016年 | 16567篇 |
2015年 | 18362篇 |
2014年 | 20972篇 |
2013年 | 24433篇 |
2012年 | 26800篇 |
2011年 | 28211篇 |
2010年 | 21083篇 |
2009年 | 21055篇 |
2008年 | 21450篇 |
2007年 | 25529篇 |
2006年 | 24371篇 |
2005年 | 20704篇 |
2004年 | 16817篇 |
2003年 | 14048篇 |
2002年 | 11177篇 |
2001年 | 8853篇 |
2000年 | 7651篇 |
1999年 | 6173篇 |
1998年 | 5031篇 |
1997年 | 3968篇 |
1996年 | 3210篇 |
1995年 | 2700篇 |
1994年 | 2398篇 |
1993年 | 1897篇 |
1992年 | 1504篇 |
1991年 | 1189篇 |
1990年 | 1001篇 |
1989年 | 786篇 |
1988年 | 541篇 |
1987年 | 406篇 |
1986年 | 331篇 |
1985年 | 440篇 |
1984年 | 420篇 |
1983年 | 287篇 |
1982年 | 318篇 |
1981年 | 156篇 |
1980年 | 178篇 |
1979年 | 66篇 |
1977年 | 36篇 |
1964年 | 37篇 |
1962年 | 68篇 |
1959年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
962.
Review on testers for measuring flow properties of bulk solids 总被引:3,自引:2,他引:1
Jörg Schwedes 《Granular Matter》2003,5(1):1-43
The author was asked by the International Fine Particle Research Institue (IFPRI) to write a critical review on shear testers
for IFPRI-members. The review was delivered to IFPRI in summer 1999. Following the contract with IFPRI it was not allowed
to publish the review elsewhere for at least two years. Granular Matter invited the author to submit the review in the original
form; during the refereeing process (besides other changes) it turned out that some remarks should be added here for clarification:
- Since 1999, the author is not aware of a really new device for testing bulk solid properties, which could lead to a change
of the general comments and conclusions provided in the review.
It was argued, that the review is referring too much to the work of Jenike, while the works of Johanson and Peschl were not
adequately cited. Both are excellent engineers with a lot of experience, but their basic ideas are not available in published
form, and if, they are not set in relation to alternative approaches so that an objective comparison in detail would be a
future research issue rather than a topic in this report.
A discussion on the influence of electrostatic charges was missing. There hardly is an influence, since the particles are
in continuous contact. Only with non-conducting plastic particles electrostatic charges could cause problems. But no relevant
experiments and results are known. In closed systems, the effect of electric charges is thus mainly neglected, but it is clear
that electrostatic forces are eminent in flows with a free surface – an issue not addressed in this review.
Received: 1 November 2002 相似文献
963.
964.
等径弯角挤压工艺(ECAEP)研究现状 总被引:3,自引:0,他引:3
等径弯角挤压是制备块状细晶材料的一种大塑性变形工艺,目前得到国内外高度重视.本文简要介绍了等径弯角挤压工艺的基本原理和变形特点,从理论上对其变形方式和机理进行了分析,并详细介绍了该工艺的应用领域。 相似文献
965.
966.
本文综术了集成电路工艺的Cu布线中Cu薄膜化学气相沉积(CVD)的研究背景,详细介绍了CVD生长Cu金属薄膜的国内外研究进展及CVD对前趋物的要求,并对前趋物的一些物理、化学性质进行了总结,最后,对薄膜沉积的计算机摸拟作了简要介绍。 相似文献
967.
《Particulate Science and Technology》2007,25(1):77-89
The removal of particulate contamination is a critical issue for many manufacturing processes. It is particularly critical to the electronics industry in which small pieces of microscopic debris remaining after chemical mechanical planarization (cmp) using submicron polishing particles can cause device failure. One way to enhance particle removal following the cmp process is to utilize surfactants. Recent research has shown ways to model the effect of surfactants on enhanced particle removal. However, previous research has not demonstrated the effect of ionic strength on enhanced particle removal associated with surfactant use. Past research has also not shown the combined effects of ionic strength and surfactant concentration on enhanced particle removal using surfactants. This article summarizes the parameters affecting particle removal, and it provides data and analysis on the effect of ionic strength as well as the combined effects of ionic strength and surfactant concentration on particle removal following cmp processing. 相似文献
968.
Patricio Toro Raúl Quijada Omar Murillo Mehrdad Yazdani‐Pedram 《Polymer International》2005,54(4):730-734
The mechanical, morphological behavior and water absorption characteristics of polypropylene (PP) and silica, or PP and rice‐husk, composites have been studied. The silica used in this study as filler was a commercial type produced from soluble glass or rice husks. The compatibilizing effect of PP grafted with monomethyl itaconate (PP‐g‐MMI) and/or with vinyltriethoxysilane (PP‐g‐VTES) as polar monomers on the mechanical properties and water absorption was also investigated. In general, a high loading of the studied fillers in the polymer matrix increases the stiffness and the water absorption capacity. This effect is more noticeable in the tensile modulus of the PP/silica composite with PP‐g‐VTES as compatibilizer. However, the increase of the rice‐husk charge as a natural filler in the PP matrix decreases the stiffness, and in the presence of PP‐g‐MMI as compatibilizer in PP/rice‐husk, the tensile modulus and water absorption of the composite were improved. The better adhesion and phase continuity in the PP/silica and PP/rice‐husk composites with different compatibilizers was confirmed by the morphological study. Copyright © 2004 Society of Chemical Industry 相似文献
969.
应用于空间关联规则挖掘的ILP方法 总被引:2,自引:0,他引:2
文章介绍了应用于空间关联规则挖掘的ILP方法。ILP方法全称为归纳逻辑程序设计,这种方法有利于从空间领域发现有价值的知识,系统地研究地理层的层次结构,处理诸多空间对象的空间特性。这种方法已在一个ILP系统SPADA中实现,该文将通过SPADA应用空间数据的一些实例来说明ILP方法的特点。 相似文献
970.