全文获取类型
收费全文 | 650097篇 |
免费 | 55175篇 |
国内免费 | 34286篇 |
学科分类
工业技术 | 739558篇 |
出版年
2024年 | 2597篇 |
2023年 | 7584篇 |
2022年 | 13835篇 |
2021年 | 17288篇 |
2020年 | 18218篇 |
2019年 | 14472篇 |
2018年 | 13573篇 |
2017年 | 17672篇 |
2016年 | 20390篇 |
2015年 | 22239篇 |
2014年 | 40518篇 |
2013年 | 36671篇 |
2012年 | 45340篇 |
2011年 | 49034篇 |
2010年 | 37209篇 |
2009年 | 38357篇 |
2008年 | 36075篇 |
2007年 | 45418篇 |
2006年 | 41896篇 |
2005年 | 36379篇 |
2004年 | 30794篇 |
2003年 | 27145篇 |
2002年 | 22218篇 |
2001年 | 18744篇 |
2000年 | 15893篇 |
1999年 | 12747篇 |
1998年 | 9659篇 |
1997年 | 8481篇 |
1996年 | 7311篇 |
1995年 | 6049篇 |
1994年 | 5258篇 |
1993年 | 3870篇 |
1992年 | 3313篇 |
1991年 | 2488篇 |
1990年 | 2096篇 |
1989年 | 1805篇 |
1988年 | 1325篇 |
1987年 | 893篇 |
1986年 | 701篇 |
1985年 | 639篇 |
1984年 | 628篇 |
1983年 | 470篇 |
1982年 | 387篇 |
1981年 | 295篇 |
1980年 | 260篇 |
1979年 | 208篇 |
1978年 | 122篇 |
1977年 | 138篇 |
1975年 | 81篇 |
1959年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
951.
某医院净化手术部空调设计 总被引:1,自引:0,他引:1
介绍了各净化间的设计参数,送、回、排风系统和自控系统的设计,以及运行情况。探讨了基于手术部湿度优先控制模式下的新风系统的设计及控制。 相似文献
952.
953.
954.
介绍了一种生产效率高、加工质量稳定、利用单片机控制液压传动系列带式输送机托辊管筒自动加工机床的设计过程。 相似文献
955.
956.
This article describes the role of certification by the American Board of Professional Psychology (ABPP) in easing the process by which psychologists move beyond their original jurisdictional boundaries to practice psychology. Meeting the requirements for licensure or certification in the various jurisdictions can be a difficult task because these requirements vary considerably from jurisdiction to jurisdiction. Other mechanisms that are available to facilitate this process include the Certificate of Professional Qualification in Psychology issued by the Association of State and Provincial Psychology Boards and certification by the National Register of Health Service Providers in Psychology. The ABPP certificate/diploma has been regarded by many state psychological associations and state boards of psychology as an appropriate way in which to recognize psychologists who are eligible for licensure/certification in a jurisdiction because of the examination requirements for board certification. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
957.
958.
The Error-in-Variables Model (EVM) applies to a large class of problems in parameter estimation in which there is error in all the variables. This property makes it of more general applicability than the widely used technique of ordinary Least Squares. While there is a voluminous literature on EVM there is nothing on a general method for designing experiments when EVM applies. In this paper we present an extension of the concept of D-optimality to provide such a general method. It is illustrated by applying it to the estimation of copolymer reactivity ratios and to fitting an ellipse. 相似文献
959.
Contemporary approaches to the certification of measurement provision software are considered in domestic and overseas publications.
Normative documentation is analyzed and a scheme is proposed for certification that takes account of the features of programs
used for metrological purposes.
__________
Translated from Izmeritel’naya Tekhnika, No. 5, pp. 65–68, May, 2007. 相似文献
960.
F. L. Lewis 《Journal of Intelligent and Robotic Systems》2007,48(4):513-523
This is an outline of research in neural networks for feedback control done since the mid 1990s at the Automation and Robotics
Research Institute (ARRI) of The University of Texas at Arlington (UTA). It shows how the developments of Intelligent Control
Systems based on neural networks have followed three main generations. This statement provides a short, broad-brush perspective
on the development of intelligent neural feedback controllers. 相似文献