全文获取类型
收费全文 | 281692篇 |
免费 | 24205篇 |
国内免费 | 12329篇 |
专业分类
电工技术 | 16519篇 |
技术理论 | 34篇 |
综合类 | 27689篇 |
化学工业 | 42940篇 |
金属工艺 | 18076篇 |
机械仪表 | 13397篇 |
建筑科学 | 37486篇 |
矿业工程 | 14459篇 |
能源动力 | 9729篇 |
轻工业 | 20952篇 |
水利工程 | 12524篇 |
石油天然气 | 14180篇 |
武器工业 | 3512篇 |
无线电 | 15785篇 |
一般工业技术 | 22475篇 |
冶金工业 | 17513篇 |
原子能技术 | 2164篇 |
自动化技术 | 28792篇 |
出版年
2024年 | 1069篇 |
2023年 | 3381篇 |
2022年 | 6776篇 |
2021年 | 9111篇 |
2020年 | 8541篇 |
2019年 | 6544篇 |
2018年 | 6179篇 |
2017年 | 7759篇 |
2016年 | 9356篇 |
2015年 | 10174篇 |
2014年 | 18323篇 |
2013年 | 16671篇 |
2012年 | 20174篇 |
2011年 | 22173篇 |
2010年 | 16691篇 |
2009年 | 17073篇 |
2008年 | 15173篇 |
2007年 | 18809篇 |
2006年 | 17391篇 |
2005年 | 15130篇 |
2004年 | 12704篇 |
2003年 | 11184篇 |
2002年 | 9109篇 |
2001年 | 7478篇 |
2000年 | 6281篇 |
1999年 | 4999篇 |
1998年 | 3574篇 |
1997年 | 3138篇 |
1996年 | 2544篇 |
1995年 | 2209篇 |
1994年 | 1839篇 |
1993年 | 1327篇 |
1992年 | 1095篇 |
1991年 | 826篇 |
1990年 | 667篇 |
1989年 | 649篇 |
1988年 | 368篇 |
1987年 | 282篇 |
1986年 | 220篇 |
1985年 | 249篇 |
1984年 | 195篇 |
1983年 | 157篇 |
1982年 | 96篇 |
1981年 | 82篇 |
1980年 | 92篇 |
1979年 | 52篇 |
1978年 | 25篇 |
1977年 | 26篇 |
1964年 | 25篇 |
1959年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
171.
172.
173.
174.
175.
An effective coding approach for multiobjective integrated resource selection and operation sequences problem 总被引:3,自引:1,他引:2
In this paper, we consider an integrated Resource Selection and Operation Sequences (iRS/OS) problem in Intelligent Manufacturing
System (IMS). Several kinds of objectives are taken into account, in which the makespan for orders should be minimized; workloads
among machine tools should be balanced; the total transition times between machines in a local plant should also be minimized.
To solve this multiobjective iRS/OS model, a new two vectors-based coding approach has been proposed to improve the efficiency
by designing a chromosome containing two kinds of information, i.e., operation sequences and machine selection. Using such
kind of chromosome, we adapt multistage operation-based Genetic Algorithm (moGA) to find the Pareto optimal solutions. Moreover
a special technique called left-shift hillclimber has been used as one kind of local search to improve the efficiency of our
algorithm. Finally, the experimental results of several iRS/OS problems indicate that our proposed approach can obtain best
solutions. Further more comparing with previous approaches, moGA performs better for finding Pareto solutions.
Received: May 2005/Accepted: December 2005 相似文献
176.
Nicolas Guerda; DeSilva Angela M.; Grey Kathleen S.; Gonzalez-Eastep Diana 《Canadian Metallurgical Quarterly》2006,37(6):702
Currently, ethnic and racial minority individuals represent a large proportion of the U.S. population, and researchers expect that they will represent the majority of the population by 2050. This shift in U.S. demographics calls for a greater awareness and integration of cultural issues into the assessment and treatment of ethnically and linguistically diverse clients. This article examines the unique beliefs and manifestations of illnesses among Haitians in connection with the American Psychological Association's (APA, 2002) Multicultural Guidelines. The authors use a common culture-bound syndrome, Séizisman, to illustrate the cultural beliefs, assessment, and treatment of illnesses among Haitians. In so doing, they demonstrate how to incorporate the APA Multicultural Guidelines into treatment with clients of diverse cultural and racial backgrounds. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
177.
178.
轻质滤料滤池的试验与研究 总被引:1,自引:0,他引:1
轻质滤料滤池是以比水密度略小的滤料为滤床的滤池,通过以净水厂的原水和污水处理厂的二级处理出水为过滤试验对象,所取得的结果表明:下向流轻质滤料滤池对浊度和悬浮固体(SS)的去除率分别可以达到80%和45%,而滤床的水头损失不超过15cm。因此轻质滤料滤池可以以预过滤的形式配置在过滤处理的净水和污水的处理工艺中。 相似文献
179.
Supported metal catalysts, particularly noble metals supported on SiO2, have attracted considerable attention due to the importance of the silica–metal interface in heterogeneous catalysis and in electronic device fabrication. Several important issues, e.g., the stability of the metal–oxide interface at working temperatures and pressures, are not well-understood. In this review, the present status of our understanding of the metal–silica interface is reviewed. Recent results of model studies in our laboratories on Pd/SiO2/Mo(1 1 2) using LEED, AES and STM are reported. In this work, epitaxial, ultrathin, well-ordered SiO2 films were grown on a Mo(1 1 2) substrate to circumvent complications that frequently arise from the silica–silicon interface present in silica thin films grown on silicon. 相似文献
180.