全文获取类型
收费全文 | 26625篇 |
免费 | 2769篇 |
国内免费 | 1354篇 |
专业分类
电工技术 | 1322篇 |
技术理论 | 3篇 |
综合类 | 2534篇 |
化学工业 | 1902篇 |
金属工艺 | 867篇 |
机械仪表 | 1889篇 |
建筑科学 | 6974篇 |
矿业工程 | 1018篇 |
能源动力 | 695篇 |
轻工业 | 1269篇 |
水利工程 | 774篇 |
石油天然气 | 2006篇 |
武器工业 | 284篇 |
无线电 | 1405篇 |
一般工业技术 | 3025篇 |
冶金工业 | 1702篇 |
原子能技术 | 193篇 |
自动化技术 | 2886篇 |
出版年
2024年 | 172篇 |
2023年 | 483篇 |
2022年 | 740篇 |
2021年 | 823篇 |
2020年 | 945篇 |
2019年 | 729篇 |
2018年 | 694篇 |
2017年 | 736篇 |
2016年 | 906篇 |
2015年 | 941篇 |
2014年 | 1569篇 |
2013年 | 1546篇 |
2012年 | 1894篇 |
2011年 | 1978篇 |
2010年 | 1613篇 |
2009年 | 1541篇 |
2008年 | 1428篇 |
2007年 | 1795篇 |
2006年 | 1626篇 |
2005年 | 1362篇 |
2004年 | 1194篇 |
2003年 | 1030篇 |
2002年 | 770篇 |
2001年 | 759篇 |
2000年 | 599篇 |
1999年 | 488篇 |
1998年 | 385篇 |
1997年 | 369篇 |
1996年 | 289篇 |
1995年 | 234篇 |
1994年 | 190篇 |
1993年 | 148篇 |
1992年 | 136篇 |
1991年 | 98篇 |
1990年 | 102篇 |
1989年 | 95篇 |
1988年 | 59篇 |
1987年 | 45篇 |
1986年 | 27篇 |
1985年 | 35篇 |
1984年 | 27篇 |
1983年 | 22篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 24篇 |
1965年 | 7篇 |
1964年 | 8篇 |
1959年 | 10篇 |
1958年 | 5篇 |
1955年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
71.
The main subject of this paper is to demonstrate the response of structural concrete to different imposed strain rates. Attention is focused on the strain rate about 10-2 s -1>, where some technical difficulties are experienced when an exact determination of mechanical properties for quasi-brittle materials is attempted. The design of a measurement system, which realizes computer acquisition, analysis, and graphic representation of data, is also presented. 相似文献
72.
Yong-Jik KimJames H. Anderson 《Information Processing Letters》2002,84(1):47-55
A simple code transformation is presented that reduces the space complexity of Yang and Anderson's local-spin mutual exclusion algorithm. In both the original and the transformed algorithm, only atomic read and write instructions are used; each process generates Θ(logN) remote memory references per lock request, where N is the number of processes. The transformed algorithm uses Θ(N) distinct variables, which is clearly optimal. 相似文献
73.
钢结构住宅的技术性探讨——以清华大学钢结构学生公寓为例 总被引:6,自引:0,他引:6
以清华大学钢结构学生公寓为实例,从结构选型、材料构成、构造技术几方面对钢结构住宅的技术性问题进行分析探讨,并提出需要进一步解决的问题。 相似文献
74.
75.
Guay Stéphane; Boisvert Jean-Marie; Freeston Mark H. 《Canadian Metallurgical Quarterly》2003,15(3):392
The goal of this study was to examine whether data from 3 different measures of communication (i.e., self-report, quasi-observational, and observational) can predict relationship adjustment and stability 1 year later when used conjointly in a sample of 62 young couples. The 3 measures of communication were the Communication Skills Test-Revised (CST-R), the Communication Box (CB), and the Demand/Withdraw Pattern Questionnaire (DWPQ). Through hierarchical multiple regression analyses, results revealed that the CST-R and the DWPQ predict both genders' relationship adjustment 1 year later when used conjointly. Logistic regression analyses revealed that none of the measures of communication significantly predicted relationship stability. In conclusion, the combination of the CST-R and the DWPQ appears to be useful for longitudinally predicting relationship adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
Tokar David M.; Withrow Jason R.; Hall Rosalie J.; Moradi Bonnie 《Canadian Metallurgical Quarterly》2003,50(1):3
Structural equation modeling was used to test theoretically based models in which psychological separation and attachment security variables were related to career indecision and those relations were mediated through vocational self-concept crystallization. In contrast to previous studies, which have found either weak or no support for a relation between separation or attachment security variables and career indecision, results based on a sample of 350 college students indicated that some components of separation and attachment security did relate to career indecision in a theoretically supportable direction. Results also revealed that regardless of whether global or component career indecision measures were used, separation and attachment security effects on indecision were at least partially mediated through vocational self-concept crystallization. The strongest mediated relations were observed for the effects of attachment anxiety and maternal separation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
77.
78.
本文介绍一种将自适应算法、遗传算法和列表调度算法结合起来应用于软硬件划分问题的算法COPARTART,并提出了一种基于约束条件的开销系数自适应调整方法,该方法所获得的划分结果能够良好体现设计目标。 相似文献
79.
复杂结构井的过套管测井技术应用 总被引:1,自引:1,他引:0
王贺林 《石油地球物理勘探》2006,41(3):357-361
过套管测井是在已下套管井中完成的用以解决油气层识别、储层物性参数计算为目的的测井系列,在复杂井中用来代替常规的裸眼测井,以便减少在大斜度井中的测井事故,缩短测井周期。本文介绍了几种常用的过套管测井技术,并将其应用于大港油田的庄海401井。结果表明,过套管测井不仅解决了油气层判别的问题,也提供了较准确的物性参数,同时降低了施工作业的难度,缩短了占井周期,这一点对海上钻井尤为重要。 相似文献
80.
Children's perceived attachments with parents, and family cohesion and adaptability were examined as predictors, mediators, and moderators in the parental problem drinking-child outcomes link. A total of 216 6- to 12-year-olds (110 boys, 106 girls) participated. Data were obtained from children and their mothers, fathers, and teachers. A higher level of family cohesion and adaptability functioned as (a) a robust protective factor against adjustment and cognitive difficulties otherwise associated with problem drinking and (b) a mediator of adjustment problems. Children's perceptions of attachments to mothers and fathers were consistent predictors of behavioral, social, and cognitive problems and further moderated relations between problem drinking and child functioning. The results support that child-parent and family functioning variables act as either pathways and/or vulnerability and protective factors for children exposed to a high-risk environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献