全文获取类型
收费全文 | 1142篇 |
免费 | 38篇 |
国内免费 | 36篇 |
专业分类
电工技术 | 33篇 |
综合类 | 80篇 |
化学工业 | 64篇 |
金属工艺 | 19篇 |
机械仪表 | 26篇 |
建筑科学 | 215篇 |
矿业工程 | 8篇 |
能源动力 | 18篇 |
轻工业 | 68篇 |
水利工程 | 2篇 |
石油天然气 | 19篇 |
武器工业 | 1篇 |
无线电 | 138篇 |
一般工业技术 | 211篇 |
冶金工业 | 26篇 |
原子能技术 | 2篇 |
自动化技术 | 286篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 11篇 |
2021年 | 27篇 |
2020年 | 23篇 |
2019年 | 18篇 |
2018年 | 26篇 |
2017年 | 31篇 |
2016年 | 54篇 |
2015年 | 58篇 |
2014年 | 124篇 |
2013年 | 96篇 |
2012年 | 76篇 |
2011年 | 84篇 |
2010年 | 82篇 |
2009年 | 53篇 |
2008年 | 68篇 |
2007年 | 68篇 |
2006年 | 54篇 |
2005年 | 50篇 |
2004年 | 43篇 |
2003年 | 47篇 |
2002年 | 31篇 |
2001年 | 22篇 |
2000年 | 15篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1980年 | 2篇 |
1965年 | 2篇 |
排序方式: 共有1216条查询结果,搜索用时 15 毫秒
31.
(利用虚拟仪器测试系统,对粘弹性材料力学参数进行纵向共振法测量。用激振器产生多周期正弦信号,激励棒状试样纵向振Ivibration and wave ; motorcycle ; transfer characteristic ; analysis ; test动,测量激振器输出端和材料自由端的加速度比值。通过共振频率及共振频率处加速度比的幅值,可以计算样本的杨氏模量和损耗因子。采集信号经过多次时域平均,可在最大程度上提高测试的信噪比。系统的测量结果与商用粘弹性仪结果是一致的。 相似文献
32.
33.
Agustín Martínez-Ruvalcaba Fausto Becerra-Bracamontes Juan C. Sánchez-Díaz Alejandro González-Álvarez 《Polymer Bulletin》2009,62(4):539-548
This work presents the synthesis of polyacrylamide-gelatin (PAM-G) semi-interpenetrating hydrogels, as well as the study of
the swelling capacity of this material at different pH’s, and we report its Young modulus. The hydrogels were crosslinked
with N,N′-methylenebisacrylamide and synthesized at different acrylamide/gelatin weight relationship. It was observed that the swelling
capacity of the hydrogels increases when the gelatin concentration is increased; while the Young modulus (at the swelling
equilibrium) decreases lightly. Therefore, the gelatin has a small effect in the Young modulus, unlike its influence in the
swelling ability. The swelling experiments reveal that the PAM-G hydrogels increase its swelling capacity in alkaline mediums
because the presence of the hydrophobic functional groups (mainly COO−) in the gelatin structure. 相似文献
34.
Similar to other countries, also in the Netherlands young male drivers (ages between 18 and 24 years) are overrepresented in crashes during weekend nights, thereby fatally injuring one or more of their passengers. This overrepresentation may be due to two contributing factors: (a) a higher exposure-to-risk because of dangerous trip condition, and (b) a higher tendency to take risks. Studies on these factors, mostly carried out in jurisdictions where youngsters are licensed at an earlier age than in Europe, suggest a strong –often negative– influence from peer-aged passengers. Given that in adolescence susceptibility to peer pressure reduces with age, these findings may not be applicable to late licensing countries, such as in Europe. In the Netherlands –a late licensing country– youngsters are licensed after the age of 18 years, followed by a 5 year probation period with a legal alcohol limit of 0.2 g/L. Further, designated driver schemes are in place since 2001, alcohol limits are enforced by random breath testing schemes, and no passenger and night time restrictions are in force. Against this background, we examined the incidence of dangerous trip conditions and risk taking among young male drivers and compared those with a reference group with a low passenger fatality rate. To that end, data on trip conditions and risk behavior were obtained from a data base on 18,608 randomly selected drivers during weekend nights in 2010, between 22:00 and 06:00. This data base held information for each randomly selected on breath alcohol concentration (BAC), license status, driver characteristics (age and gender), number of passengers, time of night, and level of urbanization. Binary logistic regression analysis confirmed the overrepresentation of young male drivers in traffic, carrying more frequently passengers than the reference group, especially after midnight. Urbanization level was not a modifying factor, but ‘time of night’ was, with riskier conditions after midnight in terms of: (a) a higher young male driver presence, (b) young male drivers carrying more frequently multiple passengers and (c) a higher prevalence of illegal BACs. After midnight, no evidence was found for a protective effect of the presence of one passenger on alcohol use. Of the young male drivers, 5% were over the legal limit and 3 in 5 young males who were over the limit carried passengers. However, the indicative result that young male drivers with multiple passengers were less likely to have been drinking than solo drivers or drivers with just one passenger, is suggestive of a protective effect of multiple passengers. These results may guide preventive strategies, including police enforcement and designated driver programmes. 相似文献
35.
Richard Rowe Gabriela D. Roman Frank P. McKenna Edward Barker Damian Poulter 《Accident; analysis and prevention》2015
The Driver Behavior Questionnaire (DBQ) is a self-report measure of driving behavior that has been widely used over more than 20 years. Despite this wealth of evidence a number of questions remain, including understanding the correlation between its violations and errors sub-components, identifying how these components are related to crash involvement, and testing whether a DBQ based on a reduced number of items can be effective. We address these issues using a bifactor modeling approach to data drawn from the UK Cohort II longitudinal study of novice drivers. This dataset provides observations on 12,012 drivers with DBQ data collected at .5, 1, 2 and 3 years after passing their test. A bifactor model, including a general factor onto which all items loaded, and specific factors for ordinary violations, aggressive violations, slips and errors fitted the data better than correlated factors and second-order factor structures. A model based on only 12 items replicated this structure and produced factor scores that were highly correlated with the full model. The ordinary violations and general factor were significant independent predictors of crash involvement at 6 months after starting independent driving. The discussion considers the role of the general and specific factors in crash involvement. 相似文献
36.
Though condensed between the stages of design and completion, the conventional process of designing a building is time consuming, involving various stakeholders, planning processes and a wide team of consultants and contractors. What happens, though, if the time period of an architect's involvement is expanded? How might a more process-orientated approach shift the role of the architect? Tobias Armborst, Daniel D'Oca and Georgeen Theodore , principals of Interboro Partners in New York, describe how they have developed projects that have sought opportunities in expanding the timescale and remit of traditional practice. 相似文献
37.
38.
基于SIM 900A的物联网智能家居控制系统 总被引:1,自引:0,他引:1
物联网技术是世界信息产业发展的第三次浪潮,它改变了人们的家居方式,使人们有希望拥有一个更加安全、方便、舒适、智能的家。文中设计了一种基于SIM900A和Cortex-M3的物联网智能家居控制系统。该系统采用Cortex-M3内核的STM32处理器来作为系统主控制器,可以采集多个传感器的信息,并通过SIM900A与多个移动终端实现物联网通信。实验结果表明,该系统可以正常接收来自移动终端的SMS信息,控制家用设备,在出现危险信号时可以快速发送警报短信,具有传输快、传输距离远、实时性强等优点。 相似文献
39.
刘传鹏 《江汉石油职工大学学报》2014,(2):86-87
当前,中国石化集团江汉石油管理局钻井一公司青年员工思想工作存在着少数青工思想上缺乏对企业的归属感,一些青工敬业精神有待加强,一些青工自我调节情绪能力较差等问题。加强青年员工思想工作,就必须引导青年员工树立正确的思想观念;关注青年员工的心理需求;发挥榜样力量鼓励后进;加强技能培训提升青年员工素质;优化酬薪制度、搭建晋级平台。 相似文献
40.
刘英 《江汉石油职工大学学报》2014,(2):94-95,104
中国石化江汉油田分公司勘探开发研究院的青年专业技术人才培养中存在着工作压力大、生活压力大、人才结构不合理、成才环境有待提高等问题。要加快青年专业技术人才培养,就必须要加强人文关怀,着力培养青年专业技术人才的责任感;要把人才梯队建设与核心技术体系的完善捆绑在一起;要着力加大岗位交流和培训力度,进一步优化和调整青年专业技术人才结构;要着力完善考评使用机制,为青年人快速成长畅通渠道,营造公平公正的用人环境;要着力培养树立"优秀青年专业技术人才"典型,激发青年专业技术人才干事创业的积极性。 相似文献