全文获取类型
收费全文 | 506篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
综合类 | 1篇 |
化学工业 | 10篇 |
机械仪表 | 2篇 |
建筑科学 | 1篇 |
矿业工程 | 9篇 |
能源动力 | 3篇 |
轻工业 | 6篇 |
无线电 | 5篇 |
一般工业技术 | 5篇 |
冶金工业 | 452篇 |
自动化技术 | 16篇 |
出版年
2021年 | 5篇 |
2020年 | 4篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2005年 | 2篇 |
2002年 | 1篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 141篇 |
1997年 | 74篇 |
1996年 | 44篇 |
1995年 | 31篇 |
1994年 | 24篇 |
1993年 | 23篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1978年 | 3篇 |
1977年 | 21篇 |
1976年 | 56篇 |
1975年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有510条查询结果,搜索用时 15 毫秒
1.
2.
3.
GI Kempen MJ van Heuvelen RH van den Brink AC Kooijman M Klein PJ Houx J Ormel 《Canadian Metallurgical Quarterly》1996,25(6):458-464
Molecular electrostatic potential (MEP) maps of certain 3-methoxy flavone derivatives having different anti-picornavirus activities have been studied. Geometries of the molecules were optimised and charge distributions computed using the AM1 molecular orbital method. Hybridization displacement charges (HDC) were combined with the L?wdin charge distributions to compute the MEP maps. Reliability of the method of computing MEP maps was tested by studying certain other molecules for which ab initio MEP results are available. The anti-picornavirus activities of the flavones have been shown to be related with negative MEP values in two regions, one near the 3-methoxy group and another in a diagonally opposite region near the substituent attached to the C7 atom of the molecules. 相似文献
4.
5.
6.
7.
Aniello Leonardo Halak Basel Chai Peter Dhall Riddhi Mihalea Mircea Wilczynski Adrian 《International Journal of Information Security》2021,20(3):445-460
International Journal of Information Security - The complexity of today’s integrated circuit (IC) supply chain, organised in several tiers and including many companies located in different... 相似文献
8.
Medico-demographic processes and socio-hygienic characteristics of the population of a large city, both at an individual and familial levels, as well as territorial characteristics of residence, should be taken into consideration when developing measures for medicosocial care of the population. Analysis of the attitude of 380 city families to the activities, personality, and professional skills of local therapists and pediatricians and to the idea of primary health care rendered by a physician of a general profile demonstrated an increased activity of the families in the "physician-patient" system and confirmed the necessity of improving medicosocial care of a city family, expansion of prophylactic work with the population with due consideration for factors which have an impact on population health. 相似文献
9.
Using the consumer-oriented approach of social and commercial marketers, this article presents a process for crafting messages designed to improve people's health behaviors. The process, termed consumer-based health communications (CHC), transforms scientific recommendations into message strategies that are relevant to the consumer. The core of CHC is consumer research conducted to understand the consumer's reality, and thereby allowing six strategic questions to be answered. The immediate result of the CHC process is a strategy statement--a few pages that lay out who the target consumer is, what action should be taken, what to promise and how to make the promise credible, how and when to reach him or her, and what image to convey. The strategy statement then guides the execution of all communication efforts, be they public relations, mass media, direct marketing, media advocacy, or interpersonal influence. It identifies the most important "levers" for contact with the consumer. Everyone from creative specialists through management and program personnel can use the strategy statement as a touchstone to guide and judge the effectiveness of their efforts. The article provides a step by step illustration of the CHC process using the 5 A Day campaign as an example. 相似文献
10.
A new controller for linear multivariable ordinary systems is suggested in which distributed delays are included in the feedback loop. A general design approach to obtain this type of controller is suggested. It is shown that the resulting closed-loop system is asymptotically stable under some sufficient conditions. Sufficient conditions are derived under which the disturbance attenuation, the robustness against parameter variations, and the time-delay stability margins are improved by the proposed controller. The state feedback tracking controller and the dual-state observer are obtained by modification of the proposed controller. 相似文献