全文获取类型
收费全文 | 10718篇 |
免费 | 823篇 |
国内免费 | 286篇 |
专业分类
电工技术 | 144篇 |
技术理论 | 3篇 |
综合类 | 1317篇 |
化学工业 | 643篇 |
金属工艺 | 133篇 |
机械仪表 | 177篇 |
建筑科学 | 4307篇 |
矿业工程 | 1940篇 |
能源动力 | 197篇 |
轻工业 | 763篇 |
水利工程 | 132篇 |
石油天然气 | 128篇 |
武器工业 | 14篇 |
无线电 | 176篇 |
一般工业技术 | 664篇 |
冶金工业 | 269篇 |
原子能技术 | 23篇 |
自动化技术 | 797篇 |
出版年
2024年 | 31篇 |
2023年 | 94篇 |
2022年 | 261篇 |
2021年 | 360篇 |
2020年 | 359篇 |
2019年 | 237篇 |
2018年 | 193篇 |
2017年 | 256篇 |
2016年 | 266篇 |
2015年 | 331篇 |
2014年 | 803篇 |
2013年 | 558篇 |
2012年 | 893篇 |
2011年 | 846篇 |
2010年 | 765篇 |
2009年 | 799篇 |
2008年 | 682篇 |
2007年 | 763篇 |
2006年 | 659篇 |
2005年 | 514篇 |
2004年 | 393篇 |
2003年 | 344篇 |
2002年 | 267篇 |
2001年 | 220篇 |
2000年 | 165篇 |
1999年 | 137篇 |
1998年 | 82篇 |
1997年 | 83篇 |
1996年 | 82篇 |
1995年 | 56篇 |
1994年 | 42篇 |
1993年 | 31篇 |
1992年 | 37篇 |
1991年 | 25篇 |
1990年 | 17篇 |
1989年 | 21篇 |
1988年 | 25篇 |
1987年 | 28篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1979年 | 3篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 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.
中国的菊花主题花展(菊花展览)是最重要的赏菊形式,对我国3种主要类型的菊花展览,即综合性菊花展览(中国菊花展览会、国际博览会菊花专项展和各级城市菊花展)、菊花专类园和菊花花田花海的发展现状进行了研究,并分析了菊花展览在促进菊花产业发展、弘扬菊花文化、服务生态文明及美丽乡村建设、加强菊花非物质文化遗产保护中的重要作用,为推动我国菊花展览水平的提高提供借鉴。 相似文献
3.
The paper considers the problem of stabilization of systems possessing a multiple zero eigenvalue at the origin. The controller that we propose, uses multiple delayed measurements instead of derivative terms. Doing so, we increase the performances of the closed loop in presence of system uncertainties and/or noisy measurements. The problem formulation and the analysis is presented through a classical engineering problem which is the stabilization of an inverted pendulum on a cart moving horizontally. On one hand, we perform a nonlinear analysis of the center dynamics described by a three dimensional system of ordinary differential equations with a codimension-three triple zero bifurcation. On the other hand, we present the complementary stability analysis of the corresponding linear time invariant system with two delays describing the behavior around the equilibrium. The aim of this analysis is to characterize the possible local bifurcations. Finally, the proposed control scheme is numerically illustrated and discussed. 相似文献
4.
为解决21000工作面采空区及顶板涌水问题,根据工作面出水点的不同情况,采取了集水器导水、老塘设挡水堰截水、挖排水沟疏水等多项治水措施,经统计排水量达33~42m3/h,有效控制了水情,确保了工作面正常生产。 相似文献
5.
The aim of this paper was to determine the content of vasoactive biogenic amines in Sremski kulen and Sremska kobasica and to estimate hygienic conditions and good manufacturing practice (GMP) according to proposed criteria. Formation of dansyl chloride derivatizated vasoactive amines were determined using HPLC–DAD. Tryptamine (47.6; 34.2 mg/kg), histamine (16.1; 6.42 mg/kg) and tyramine (95.1; 45.2 mg/kg) were detected in both investigated type of traditional dry fermented sausages while phenylethylamine was not detected. Total content of vasoactive amines did not exceed the sum (200 mg/kg) proposed as a possible indicator of hygienic conditions and GMP in sausage production. 相似文献
6.
In this article, the authors study the factorial structure of 2 versions (64 items and 32 items) of the Dutch translation of the Inventory of Interpersonal Problems (IIP; L. M. Horowitz, L. E. Alden, J. S. Wiggins, & A. L. Pincus, 2000) in both a clinical sample (n = 382) and a student sample (n = 287). First, the authors test whether both inventories are constituted by correlated uni-dimensional subscales, and they conclude that this is true only for the short version. Second, the authors study whether the correlations between the subscales follow a circumplex pattern. This proves to be true for both versions. Coefficients alpha and correlations between the IIP-64 and IIP-32 subscales are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
WANG Jiqing 《声学技术》2003,22(Z1)
The traditional performing arts and theatrical buildings in China can be traced back to a long history and were well developed during Song and Yuan Dynasties, 11th-14th centuries. Pavilion stage, opened on three sides and thrusting into the audience area, was unique and the most popular form in the open-air theatres, the courtyard theatres, and the indoor theatres up to the present day. As the traditional Chinese opera is performed in an abstract way, no stage settings are required and used. Therefore, the pavilion stage including the flat or domed ceiling and the back wall is virtually functioned as a reflective shell, which increases the early reflections and also intensifies the sound in the audience area. Meanwhile, it provides sufficient self-support to the performers. Acoustical parameters including reverberation time RT, early decay time EDT, acoustic ratio C50, strength index (loudness) G, and stage support factor ST1 were measured and reported on several traditional theatrical buildings. 相似文献
8.
介绍了铁路电力试验车软件的设计思想、框架结构及其总体控制策略 ,并就其中的测试程序、数据库管理系统、串口通讯程序、复杂式样报表生成和系统安装程序的设计策略作了叙述。 相似文献
9.
蒸汽是石油化工装置中最重要的物料。随着石油化工工业的迅猛发展 ,蒸汽在其中扮演着越来越重要的多重角色。因此 ,对蒸汽系统的平稳控制 ,对石油化工生产装置平稳、高效地运行是至关重要的。传统的蒸汽减压站自控系统基建投资大 ,紧急情况下靠人工手动操作稳定蒸汽压力系统 ,往往造成生产的波动或大面积的停车。针对传统蒸汽减压站自控系统的弱点 ,提出蒸汽减压站自控系统的优化设计方案 ,该方案得以在大型生产装置成功应用。新方案不但节省了大量的基建投资 ,而且取得了良好的生产效益 相似文献
10.
介绍了大同煤矿集团公司挖金湾矿断层构造情况。总结了技术经验,针对具体条件,该矿综采过断层采煤采取了直接割煤、割顶(底)和预掘巷与割底相结合等过断层措施,取得了较好的效果。 相似文献