全文获取类型
收费全文 | 1605篇 |
免费 | 38篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 36篇 |
综合类 | 2篇 |
化学工业 | 456篇 |
金属工艺 | 33篇 |
机械仪表 | 15篇 |
建筑科学 | 88篇 |
矿业工程 | 8篇 |
能源动力 | 28篇 |
轻工业 | 259篇 |
水利工程 | 10篇 |
石油天然气 | 1篇 |
无线电 | 70篇 |
一般工业技术 | 223篇 |
冶金工业 | 249篇 |
原子能技术 | 7篇 |
自动化技术 | 160篇 |
出版年
2022年 | 23篇 |
2021年 | 33篇 |
2020年 | 22篇 |
2019年 | 28篇 |
2018年 | 21篇 |
2017年 | 14篇 |
2016年 | 30篇 |
2015年 | 29篇 |
2014年 | 35篇 |
2013年 | 54篇 |
2012年 | 49篇 |
2011年 | 65篇 |
2010年 | 57篇 |
2009年 | 45篇 |
2008年 | 47篇 |
2007年 | 58篇 |
2006年 | 46篇 |
2005年 | 37篇 |
2004年 | 39篇 |
2003年 | 35篇 |
2002年 | 35篇 |
2001年 | 14篇 |
2000年 | 29篇 |
1999年 | 14篇 |
1998年 | 35篇 |
1997年 | 36篇 |
1996年 | 27篇 |
1995年 | 26篇 |
1994年 | 29篇 |
1993年 | 26篇 |
1992年 | 39篇 |
1991年 | 19篇 |
1990年 | 32篇 |
1989年 | 25篇 |
1988年 | 14篇 |
1987年 | 24篇 |
1986年 | 14篇 |
1985年 | 29篇 |
1984年 | 24篇 |
1983年 | 24篇 |
1982年 | 16篇 |
1981年 | 25篇 |
1980年 | 15篇 |
1978年 | 25篇 |
1977年 | 16篇 |
1976年 | 19篇 |
1974年 | 13篇 |
1972年 | 15篇 |
1970年 | 14篇 |
1963年 | 13篇 |
排序方式: 共有1645条查询结果,搜索用时 15 毫秒
1.
Konstantinos Spyrou Matteo Calvaresi Evmorfia K. Diamanti Theodoros Tsoufis Dimitrios Gournis Petra Rudolf Francesco Zerbetto 《Advanced functional materials》2015,25(2):263-269
Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molecules prefer to covalently connect to the graphene oxide matrix via chemical grafting, while napthalene amine molecules bind with the graphene oxide surface through π–π interactions. The presence of intercalated aromatic molecules between the graphene oxide layers is demonstrated by X‐ray diffraction, while the type of interaction between graphene oxide and polycyclic organic molecules is elucidated by X‐ray photoelectron spectroscopy. Combined quantum mechanical and molecular mechanical calculations describe the intercalation mechanism and the aniline grafting, rationalizing the experimental data. The present work opens new perspectives for the interaction of various aromatic molecules with graphite oxide and the so‐called “intercalation chemistry”. 相似文献
2.
3.
Rudolf Habison 《International Journal of Project Management》1985,3(3):178-181
Meeting time and cost objectives in complex projects involves specific problems and risks. An attempt is made to analyse the components of total cost increase of a project caused by time delay. An outline is given as to how these considerations can be used to estimate cost increases in investors' decision situations as well as to ascertain fair contractual penalties and claims for compensation and for the evaluation of justified project acceleration costs. 相似文献
4.
5.
6.
7.
R. Bunk U. Leske R. Krompass Z. Pretch K. Rudolf R. Herbig K. Pitch V. A. Tsykanov O. V. Skiba V. A. Makarov L. P. Bol'shakov P. T. Porodnov A. A. Maershin S. S. Keruchen'ko 《Atomic Energy》1989,67(5):802-806
Translated from Atomnaya Énergiya, Vol. 67, No. 5, pp. 320–323, November, 1989. 相似文献
8.
This paper reports on an evaluation of real-time properties of MAP (Manufacturing Automation Protocol) networks by analytical considerations and measurements. Based on a model of the time schedule of a communication cycle figures for response times (transport system) and message delays (MAC layer) are given. The influence of some options for handling acknowledgments within the transport layer is shown. The message delay at MAC layer is separated into an implementation-dependent and a protocol-dependent protion, and an upper bound is derived. Rules for selecting protocol parameters affecting real time behavior are given. Aspects for improved implementations of communication controllers for MAP networks are discussed. 相似文献
9.
Examined pre- and posttreatment changes in life stressors and social resources and their association with treatment outcomes in a 12-mo follow-up of 424 Ss (aged 18–83 yrs) with unipolar depression. Assessment measures included the Family Environment Scale, Work Environment Scale, and Health and Daily Living Form. As expected, Ss reported significant, multidimensional improvements in their functioning at follow-up. There were modest increases in Ss' social resources but, suprisingly, no overall decrease in stressors. Life stress and resource factors were significantly related to Ss' functioning at follow-up, even after considering the severity of their dysfunction at treatment intake and their length of treatment. Implications for developing a general body of knowledge about the process of recovery and relapse in behavioral disorders are discussed. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Rudolf E. Greuer 《Fire Safety Journal》1985,9(1):81-87
Physical principles governing mine ventilation systems and state of the art ventilation modeling are initially outlined. Several computer programs for modeling the mine ventilation-mine fire interaction, which were developed during the last decade, are then described. An older program considers fires and ventilation systems as going through a sequence of steady state conditions. Airflow rates, pressure losses, temperatures, fume and methane concentrations can be determined. Newer programs allow transient state fume concentration calculations under the assumption of constant airflow rates as well as the determination of fume exposures of escaping miners. Recent work attempts the complete transient state simulation of fires and all ventilation properties. 相似文献