全文获取类型
收费全文 | 2164篇 |
免费 | 17篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 19篇 |
综合类 | 1篇 |
化学工业 | 325篇 |
金属工艺 | 41篇 |
机械仪表 | 41篇 |
建筑科学 | 82篇 |
矿业工程 | 15篇 |
能源动力 | 51篇 |
轻工业 | 188篇 |
水利工程 | 32篇 |
石油天然气 | 18篇 |
无线电 | 126篇 |
一般工业技术 | 259篇 |
冶金工业 | 579篇 |
原子能技术 | 12篇 |
自动化技术 | 395篇 |
出版年
2022年 | 12篇 |
2021年 | 12篇 |
2019年 | 14篇 |
2018年 | 13篇 |
2017年 | 13篇 |
2016年 | 22篇 |
2015年 | 13篇 |
2014年 | 29篇 |
2013年 | 106篇 |
2012年 | 56篇 |
2011年 | 74篇 |
2010年 | 60篇 |
2009年 | 57篇 |
2008年 | 77篇 |
2007年 | 78篇 |
2006年 | 86篇 |
2005年 | 78篇 |
2004年 | 80篇 |
2003年 | 71篇 |
2002年 | 60篇 |
2001年 | 55篇 |
2000年 | 40篇 |
1999年 | 31篇 |
1998年 | 45篇 |
1997年 | 54篇 |
1996年 | 62篇 |
1995年 | 52篇 |
1994年 | 35篇 |
1993年 | 63篇 |
1992年 | 63篇 |
1991年 | 34篇 |
1990年 | 38篇 |
1989年 | 57篇 |
1988年 | 40篇 |
1987年 | 49篇 |
1986年 | 31篇 |
1985年 | 33篇 |
1984年 | 53篇 |
1983年 | 41篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 24篇 |
1979年 | 24篇 |
1978年 | 28篇 |
1977年 | 22篇 |
1976年 | 20篇 |
1975年 | 22篇 |
1974年 | 29篇 |
1973年 | 17篇 |
1971年 | 12篇 |
排序方式: 共有2184条查询结果,搜索用时 31 毫秒
1.
Larry Gillard 《电子产品世界》2003,(14):31-32
从电力与精确数字、模拟信号,到高压气态和液态介质,如今的用户定制电缆几乎无所不传。线缆制造商们现在可以提供的连接线缆材料可谓五花八门,从多种规格的传统铜线和光纤,到各类软管和导管,甚至包括碳纤维等半导体材料。在对一种专用电缆的设计作出最终决定前,要做一点“外形匹配”的工作。通常要回答的问题包括:“要传输些什么?”、“有什么限制条件?”、“完成任务应该采用何种连接物”。在进行优化的阶段,还要另外考虑使用环境,包括可能存在的电磁干扰、机械应力影响(如扭曲和/或摩擦)、化学和/或高温的损伤。细绞合铜导线在进行大功率… 相似文献
2.
Larry Bennett 《Journal of Urban Affairs》1987,9(3):263-276
ABSTRACT: In 1983 Chicago elected its first black mayor, Harold Washington. During Washington's first term of office, his administration not only reordered municipal priorities in such a fashion as to benefit his core, minority voting constituency, but also defined a municipal agenda emphasizing greater attention to neighborhood needs and more open government. In 1984 an important neighborhood coalition, the Save Our Neighborhoods/Save Our City Coalition (SON/SOC), proposed a linked development policy to tap downtown investment for neighborhood projects. Although SON/SOC's proposal was compatible with the Washington neighborhood agenda, this mainly white organization and the Washington administration experienced considerable difficulty in forging a mutually acceptable proposal The linked development debate in Chicago demonstrates the salience of race, class-cultural factors, and alternative approaches to neighborhood mobilization as barriers to the development of progressive coalitions in city politics. 相似文献
3.
The increasing complecity of many expert system application areas calls for the integration of the knowledge of multiple experts. The use of multiple experts introduces some interesting new problems during the process of knowledge acquisition. The problems are further complicated when the experts are geographically dispersed or unavailable for face-to-face interactions.
This article discusses the motivations for acquiring the knowledge of multiple experts, the problems related to knowledge acquisition, new issues that arise whens multiple experts interact, solutions that can be brought to bear in building multiple expert systems (particularly when experts are geographically dispersed), and new tools for knowledge engineers to use when dealing with multiple experts. 相似文献
4.
5.
Larry D. Philips 《中国宝石》2006,15(1):204-206
珠宝首饰的评估在美国的发展也是循序渐进的,依据市场与需求进行的,珠宝评估业的规模正在不断扩大,所提供的服务也正在细化,并向更加专业化的方向发展。 相似文献
6.
Malik Mary L.; Beutler Larry E.; Alimohamed Shabia; Gallagher-Thompson Dolores; Thompson Larry 《Canadian Metallurgical Quarterly》2003,71(1):150
The definition of an empirically supported treatment (EST) arguably embodies 2 untested assumptions: (a) that different manualized renditions of the same therapy are functionally equivalent and (b) that therapies can be reliably applied independently of therapist, setting, and format. These assumptions were tested as applied to cognitive therapy (CT), using process data from a large multisite study (N=235) that included 3 cognitive and 6 alternative therapies. Although the non-CTs were more variable than the CTs on 2 of 4 dimensions studied (directiveness and emotional arousal), there was considerable variation among the 3 CTs, even when implemented in the current context of rigorous training, manualization, and adherence checks. Results are discussed as related to the assumptions underlying EST criteria. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
8.
9.
Barry Steinhardt 《突发事故与危机管理杂志》2003,11(1):32-36
A few years ago, Sun Microsystems CEO Scott McNealy created uproar by declaring: ‘You have zero privacy. Get over it.’ ( Sprenger, 1999 ) The question, at least for Americans, is did the 11 September terrorist attacks – and the response to them – prove him right? Is privacy really dead? 相似文献
10.