全文获取类型
收费全文 | 936篇 |
免费 | 42篇 |
国内免费 | 53篇 |
专业分类
电工技术 | 25篇 |
综合类 | 112篇 |
化学工业 | 20篇 |
金属工艺 | 7篇 |
机械仪表 | 60篇 |
建筑科学 | 128篇 |
矿业工程 | 35篇 |
能源动力 | 25篇 |
轻工业 | 6篇 |
水利工程 | 24篇 |
石油天然气 | 33篇 |
武器工业 | 2篇 |
无线电 | 95篇 |
一般工业技术 | 25篇 |
冶金工业 | 53篇 |
原子能技术 | 5篇 |
自动化技术 | 376篇 |
出版年
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 19篇 |
2020年 | 21篇 |
2019年 | 11篇 |
2018年 | 10篇 |
2017年 | 17篇 |
2016年 | 21篇 |
2015年 | 19篇 |
2014年 | 55篇 |
2013年 | 50篇 |
2012年 | 56篇 |
2011年 | 69篇 |
2010年 | 56篇 |
2009年 | 51篇 |
2008年 | 56篇 |
2007年 | 68篇 |
2006年 | 67篇 |
2005年 | 62篇 |
2004年 | 58篇 |
2003年 | 51篇 |
2002年 | 36篇 |
2001年 | 30篇 |
2000年 | 31篇 |
1999年 | 29篇 |
1998年 | 22篇 |
1997年 | 10篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1031条查询结果,搜索用时 15 毫秒
1.
�ҹ���Ȼ���۸����״���ĸ﷽���̽ 总被引:9,自引:6,他引:3
当今世界各国执行的商品天然气定价原则主要包括完全成本原则、平均利润原则、长期边际成本定价原则、比价合理原则和供求平衡原则等。文章分析了我国天然气价格的演变历史及现状,说明了现行价格形成的制度原因。研究了天然气商品从生产到运输再到销售各环节的价格确定方法,以此为基础给出了一个即考虑天然气商品价值又考虑竞争和政府管制因素的天然气商品的定价公式。文章最后指出,在真正的、完全竞争的天然气市场建立之前,商品天然气的价格主要应按完全成本原则进行确定。 相似文献
2.
在国际工程承包中,银行保函是一种常用的担保形式,也是商业银行表外业务的一种。笔者主要介绍保函的种类、办理银行保函的一般程序、开具银行保函的注意事项等内容,为从事国际工程承包业务的管理提供参考。 相似文献
3.
Management is aware that the value of firms is the ultimate measure of company performance. However, management has been using common accounting measures as an operating guide because the linkage between operational planning and value is vague and complex and, therefore, difficult to apply. Managers need to have clear targets and performance measures to track progress. This paper examines if a set of common accounting performance measures are linked tightly to the overall value of the firm. An abductive learning network (ALN) approach, an artificial intelligence technique, is used in this research because an ALN approach is non-parametric and can capture a subtle dynamic relationship between input and output variables, which is not obvious in linear statistical analysis. Empirical results show that an ALN model is very effective in synthesizing the value of the firm using six common accounting variables. The results also provide four strategic variables that can be used for devising strategic and operating plans to maximize the value of firms. 相似文献
4.
针对目前企业固定资产投资中存在的投资超概算问题 ,论述了实行工程预决算审计的必要性 ,结合江西铜业股份有限公司的实践阐明了如何实行工程预决算审计 ,以达到提高投资效益的目的。 相似文献
5.
对营利性医疗机构与非营利性医疗机构两者之间的同一性问题,从主导地位与组 成部分和相互促进、相互转化三个方面进行了探讨。 相似文献
6.
7.
The paper presents a model for the collaboration among independent freight forwarding entities. In the modern highly competitive transportation branch freight forwarders reduce their fulfillment costs by exploiting different execution modes (self-fulfillment and subcontraction). For self-fulfillment they use their own vehicles to execute the requests and for subcontracting they forward the orders to external freight carriers. Further enhancement of competitiveness can be achieved if the freight forwarders cooperate in coalitions in order to balance their request portfolios. Participation in such a coalition gains additional profit for the entire coalition and for each participant, therefore reinforcing the market position of the partners. The integrated operational transport problem as well as existing collaboration approaches are introduced. The presented model for collaboration is based on theoretical foundations in the field of combinatorial auctions and operational research game theory. It is applicable for coalitions of freight forwarders, especially for the collaboration of Profit Centres within large freight forwarding companies. The proposed theoretical approach and the presented collaboration model are suitable for a coalition of freight forwarding companies with nearly similar potential on the market. 相似文献
8.
By combining the theory with the practice,the dynamic current shar-ing in paralleling power MOSFET is analysed.The principles of choosing parameters in-fluencing dynamic current sharing are described,and some experiment results are given on the basis of these steps. 相似文献
9.
C. Christopher ColumbusAuthor Vitae K. Chandrasekaran Author VitaeSishaj P. Simon Author Vitae 《Applied Soft Computing》2012,12(1):145-160
This paper proposes a nodal ant colony optimization (NACO) technique to solve profit based unit commitment problem (PBUCP). Generation companies (GENCOs) in a competitive restructured power market, schedule their generators with an objective to maximize their own profit without any regard for system social benefit. Power and reserve prices become important factors in decision process. Ant colony optimization that mimics the behavior of ants foraging activities is suitably implemented to search the UCP search space. Here a search space consisting of optimal combination of binary nodes for unit ON/OFF status is represented for the movement of the ants to maintain good exploration and exploitation search capabilities. The proposed model help GENCOs to make decisions on the quantity of power and reserve that must be put up for sale in the markets and also to schedule generators in order to receive the maximum profit. The effectiveness of the proposed technique for PBUCP is validated on 10 and 36 generating unit systems available in the literature. NACO yields an increase of profit, greater than 1.5%, in comparison with the basic ACO, Muller method and hybrid LR-GA. 相似文献
10.