全文获取类型
收费全文 | 10118篇 |
免费 | 686篇 |
国内免费 | 388篇 |
专业分类
电工技术 | 584篇 |
综合类 | 394篇 |
化学工业 | 778篇 |
金属工艺 | 697篇 |
机械仪表 | 1014篇 |
建筑科学 | 378篇 |
矿业工程 | 240篇 |
能源动力 | 421篇 |
轻工业 | 212篇 |
水利工程 | 77篇 |
石油天然气 | 189篇 |
武器工业 | 56篇 |
无线电 | 2224篇 |
一般工业技术 | 812篇 |
冶金工业 | 741篇 |
原子能技术 | 95篇 |
自动化技术 | 2280篇 |
出版年
2024年 | 18篇 |
2023年 | 97篇 |
2022年 | 151篇 |
2021年 | 178篇 |
2020年 | 159篇 |
2019年 | 168篇 |
2018年 | 179篇 |
2017年 | 225篇 |
2016年 | 275篇 |
2015年 | 332篇 |
2014年 | 525篇 |
2013年 | 599篇 |
2012年 | 615篇 |
2011年 | 788篇 |
2010年 | 618篇 |
2009年 | 566篇 |
2008年 | 548篇 |
2007年 | 695篇 |
2006年 | 646篇 |
2005年 | 554篇 |
2004年 | 422篇 |
2003年 | 387篇 |
2002年 | 308篇 |
2001年 | 255篇 |
2000年 | 226篇 |
1999年 | 264篇 |
1998年 | 212篇 |
1997年 | 208篇 |
1996年 | 220篇 |
1995年 | 143篇 |
1994年 | 161篇 |
1993年 | 119篇 |
1992年 | 84篇 |
1991年 | 62篇 |
1990年 | 48篇 |
1989年 | 34篇 |
1988年 | 37篇 |
1987年 | 22篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
1.
M. R. Thompson 《Drug development and industrial pharmacy》2015,41(8):1223-1231
Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique. 相似文献
2.
Eight datasets of 1-h black carbon (BC) concentrations measured in Warsaw agglomeration (Poland), at urban background and sub-urban sites, and in Racibórz, a small town in Upper Silesia district (regional background site) were analyzed to evaluate BC levels, daily profiles and statistical distributions of concentrations in Central-Eastern European region. The observed mean levels ranged from 1483 ng m−3 in suburban site during summer to 3358 ng m−3 in regional background site in winter. Observed diurnal patterns were bimodal in the locations dominated by traffic emissions, but unimodal, with elevated evening peak in individually heated residential area. Three theoretical frequency distributions were applied to fit analyzed datasets separately. The lognormal distribution was the most appropriate to represent the middle-range values, while the high concentrations were satisfactorily predicted by the type I two-parameter exponential distribution which was used to estimate the return periods of extreme concentrations for winter months. 相似文献
3.
4.
托盘能否有效运用对物流的畅通与否关系重大,这已经引起了国内外专家和学者们的重视,并就此制定了托盘电子信息化管理系统,旨在更合理地使用托盘,推进托盘一体化和共用系统的建立。而RFID技术在托盘的电子信息化管理的应用更将大大提高物流的效率与准确性,托盘电子信息化管理将成为今后托盘管理的趋势。 相似文献
5.
6.
介绍一种经济实用的用普通磁带记录与回放超低频信号的方法,该方法在地质,建筑工程和医疗等行业中有一定的实用价值。 相似文献
7.
简要介绍世界几种主要薄板坯连铸工艺。着重叙述应用大型通用商业软件MSC.MARC。模拟液芯压下时铸坯的变形,确定最佳压下方案的有限元分析,液芯压下应该在结晶器出口处及二冷区扇形段开始部分进行,这样能减小铸坯的应变。 相似文献
8.
9.
2005年11月份邯郸钢铁厂8万煤气柜外送煤气加压机采用高压变频技术改造。其原因是该加压机外送量波动较大,采用普通阀门调节打回流,将会浪费大量电能,采用变频技术改造后,节能效果非常明显。 相似文献
10.
This paper describes the elastic response of a block sample of compressible Chicago glacial clay under a variety of stresses and its relationship with the deformation characteristics at relatively large strains. The elastic shear stiffness was obtained from bender element tests during consolidation and shearing in drained triaxial stress probe tests. An empirical correlation was established based on the elastic shear stiffness in a preyield condition. By comparing the empirical correlation with the measured elastic shear stiffness in the stress region during probing, the changes of elastic shear stiffness were investigated. The departure of elastic shear stiffness from values computed by the empirical relation based on K0 loading directly relates to the yielding characteristics of the clay. The large-scale change of soil structure at yielding alters the well-established relationship between the elastic shear stiffness and stresses in the preyield condition. The mechanical yielding response of clays can be detected based on the systematic analysis of the elastic shear wave velocities. 相似文献