全文获取类型
收费全文 | 281972篇 |
免费 | 22925篇 |
国内免费 | 11871篇 |
专业分类
电工技术 | 19249篇 |
技术理论 | 45篇 |
综合类 | 29569篇 |
化学工业 | 28961篇 |
金属工艺 | 10187篇 |
机械仪表 | 14154篇 |
建筑科学 | 43624篇 |
矿业工程 | 15181篇 |
能源动力 | 9806篇 |
轻工业 | 17531篇 |
水利工程 | 14346篇 |
石油天然气 | 13126篇 |
武器工业 | 3467篇 |
无线电 | 19167篇 |
一般工业技术 | 19341篇 |
冶金工业 | 15787篇 |
原子能技术 | 2088篇 |
自动化技术 | 41139篇 |
出版年
2024年 | 735篇 |
2023年 | 3108篇 |
2022年 | 5965篇 |
2021年 | 8342篇 |
2020年 | 8054篇 |
2019年 | 6057篇 |
2018年 | 5670篇 |
2017年 | 7185篇 |
2016年 | 9016篇 |
2015年 | 9884篇 |
2014年 | 20288篇 |
2013年 | 17240篇 |
2012年 | 20325篇 |
2011年 | 22499篇 |
2010年 | 16783篇 |
2009年 | 17369篇 |
2008年 | 16281篇 |
2007年 | 19791篇 |
2006年 | 17712篇 |
2005年 | 15344篇 |
2004年 | 12914篇 |
2003年 | 11327篇 |
2002年 | 9129篇 |
2001年 | 7306篇 |
2000年 | 6096篇 |
1999年 | 4714篇 |
1998年 | 3329篇 |
1997年 | 2820篇 |
1996年 | 2287篇 |
1995年 | 1914篇 |
1994年 | 1557篇 |
1993年 | 1139篇 |
1992年 | 891篇 |
1991年 | 635篇 |
1990年 | 532篇 |
1989年 | 520篇 |
1988年 | 309篇 |
1987年 | 219篇 |
1986年 | 221篇 |
1985年 | 259篇 |
1984年 | 208篇 |
1983年 | 184篇 |
1982年 | 80篇 |
1981年 | 92篇 |
1980年 | 89篇 |
1979年 | 50篇 |
1978年 | 26篇 |
1977年 | 36篇 |
1975年 | 22篇 |
1959年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
941.
目前人体工程学的应用领域主要集中于机器或生产环境等“硬”系统的研究与设计,其设计的思想、内容与程序对具有“软”系统特征的管理系统设计具有深远影响。文章对管理系统设计中的人体工程设计思想进行了讨论。 相似文献
942.
Stakeholder involvement is essential to the development of a total maximum daily load (TMDL) and its implementation plan. A tool, beyond a simulation model, is needed to support the decision making process that requires negotiation and compromise among stakeholders. The decision support system (DSS) described herein has a TMDL module to calculate various combinations of point and nonpoint loads that can meet the water quality criteria. Its Consensus module allows stakeholders to formulate, evaluate, modify, and vote for alternatives. The DSS displays bar charts for pollution loads from various subwatersheds and attributes the nonpoint loads to land uses. The water quality consequence of the pollution loads is output in maps, which shows sections meeting criteria in green and those not in red. The DSS requires a front end effort of site specific adaptation and model calibration. An Internet-based stakeholder process was developed to allow more concerned citizens to participate in management decisions. 相似文献
943.
陈德荣 《陶瓷研究与职业教育》2003,1(1):25-27
高等职业技术教育要求把握好理论教学与实践教学的关系,探索适合培养目标的教学方法,综合运用多种教学方法,十分重视搞好实践教学,适度调整教材结构和测评方法,把教书与育人结合起来。 相似文献
944.
浅谈黄土高原重点水土流失区的林业生态工程建设 总被引:5,自引:0,他引:5
黄土高原重点水土流失区林业生态工程建设的现状可以用“三低”(造林成活率低、保存率低、林木生长率低)来概括,人工林具有矮化,纤细,低产,烯疏4个特征,自然条件,适地适树、苗木质量、造林技术、抚育管护等5个方面的问题是造成“三低”的主要原因,适地适树适法是现阶段防治中造林“三低”的主要技术途径,其核心是“林水平衡”合理布局,适地适树,重视经济树种、抗旱造林以及加强病、虫、鼠、免、牛、羊、危害防治,是搞好区内林业生态建设的主要技术措施。 相似文献
945.
This paper discusses the need for interface management within construction, with particular reference to building facade interfaces. It categorizes the three different types of interface management—physical, contractual, and organizational. The implication of interface management in construction contracting is discussed; it is explained how the U.K. procurement trends have changed, affecting the interface management within projects. U.K. cladding procurement is very fragmented, and the paper maps the development of a typical cladding system showing the complexities of interface management. Finally, the paper discusses CladdISS, a U.K. government funded research project to develop a standardized strategy for the design and management of window and cladding interfaces. It explains the principles of CladdISS with reference to process maps, action plans, management strategy, bibliography, advice on standards, materials, maintenance, joints, movement, and tolerances. This will enable strategies to be developed to avoid the endemic interface problems occurring on-site. It will also guide the management of the interfaces throughout the project. 相似文献
946.
中国冷库的现状与发展趋势 总被引:8,自引:0,他引:8
张保生 《制冷与空调(四川)》2003,(2):21-24
本文从的设计建造、制冷工艺和管理维护这三个方面,介绍了近三年来中国冷库的现状,说明中国冷库正朝着灵活、自动化、节能和环保的方向进一步发展。 相似文献
947.
加强石油天然气工业的立法,是社会主义市场经济发展与油气勘查开采实践的需要。针对现行油气管理法规在矿种管理体制,相邻采矿权人关系,油气采矿人主体资格,解决采矿权纠纷等未明事项,运用法学理论进行了剖析;阐述了加强油气立法工作的必要性和紧迫性;并有针对性地提立法建议,以期引探讨和有关部门重视。 相似文献
948.
从油气勘探、开发投资的特性出发,正确选择投资绩效评价指标,是保证评价科学性以及进行中外对比研究的前提条件。 相似文献
949.
950.
We have evaluated the extent of public concerns about water management in the Palestinian Territory (PT) through a survey of the main Palestinian newspaper over the last thirteen years divided in three periods: pre (1984–1987), during (1988–1991), and post national uprising period (1992–1996). The public concern in the PT about various water management aspects was clear and influenced by the prevailing political conditions indicating (1) poor concerns in the first and second period where full Israeli military control of the PT and harsh practices prevailed with relatively more emphasis on regional water issues and (2) extensive-strong concerns in the third period when the peace process started and a partial lift of some of the Israeli water practices took place, along with an increased freedom in expressing public concerns which was granted with more emphasis on local issues and problems. Lack and limitation of water available to Palestinians, alternative solutions, and water quality and pollution control constituted the overwhelming majority of the topics of concern to the public for the three periods studied. Palestinian concerns were always greater than regional ones for the three periods and all of the topics considered. Public concern in the PT about all other water management aspects was poor and negligible especially in the first two periods. A massive increase in public concern has been observed in the third period in which the public expressed their concern over most water management aspects, indicating a possible change in public attitude toward water and water management and reflecting the change of the political status by the start of the peace process and the signing of the peace agreements. 相似文献