全文获取类型
收费全文 | 13225篇 |
免费 | 657篇 |
国内免费 | 31篇 |
专业分类
电工技术 | 171篇 |
综合类 | 23篇 |
化学工业 | 3359篇 |
金属工艺 | 248篇 |
机械仪表 | 292篇 |
建筑科学 | 609篇 |
矿业工程 | 42篇 |
能源动力 | 325篇 |
轻工业 | 801篇 |
水利工程 | 94篇 |
石油天然气 | 50篇 |
无线电 | 994篇 |
一般工业技术 | 2937篇 |
冶金工业 | 1753篇 |
原子能技术 | 136篇 |
自动化技术 | 2079篇 |
出版年
2023年 | 172篇 |
2022年 | 419篇 |
2021年 | 459篇 |
2020年 | 326篇 |
2019年 | 293篇 |
2018年 | 352篇 |
2017年 | 327篇 |
2016年 | 430篇 |
2015年 | 351篇 |
2014年 | 533篇 |
2013年 | 832篇 |
2012年 | 684篇 |
2011年 | 819篇 |
2010年 | 601篇 |
2009年 | 568篇 |
2008年 | 611篇 |
2007年 | 595篇 |
2006年 | 495篇 |
2005年 | 392篇 |
2004年 | 352篇 |
2003年 | 322篇 |
2002年 | 292篇 |
2001年 | 207篇 |
2000年 | 181篇 |
1999年 | 184篇 |
1998年 | 282篇 |
1997年 | 232篇 |
1996年 | 159篇 |
1995年 | 142篇 |
1994年 | 142篇 |
1993年 | 147篇 |
1992年 | 104篇 |
1991年 | 99篇 |
1990年 | 106篇 |
1989年 | 102篇 |
1988年 | 104篇 |
1987年 | 76篇 |
1986年 | 91篇 |
1985年 | 100篇 |
1984年 | 98篇 |
1983年 | 82篇 |
1982年 | 79篇 |
1981年 | 82篇 |
1980年 | 68篇 |
1979年 | 76篇 |
1978年 | 86篇 |
1977年 | 70篇 |
1976年 | 103篇 |
1975年 | 59篇 |
1973年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
1.
During large scale wildfires, suppression activities are carried out under the direction of an Incident Management Team (IMT). The aim of the research was to increase understanding of decision processes potentially related to IMT effectiveness. An IMT comprises four major functions: Command, Operations, Planning, and Logistics. Four methodologies were used to study IMT processes: computer simulation experiments; analyses of wildfire reports; interviews with IMT members; and cognitive ethnographic studies of IMTs. Three processes were important determinants of IMT effectiveness: information management and cognitive overload; matching component function goals to overall goals; and team metacognition to detect and counter task‐disruptive developments. These processes appear to be complex multi‐person analogues of individual Incident Command processes identified previously. The findings have implications for issues such as: creating IMTs; training IMTs; managing IMTs; and providing decision support to IMTs. 相似文献
2.
3.
Roger L. Kemp 《Cities》1985,2(3):252-255
Since the early 1970s, local governments in the USA have faced limited tax income combined with double-digit inflation. As a result, every local service from fire prevention to recreation has had to be closely scrutinized. Local administrators and politicians have evolved new and innovative retrenchment management policies to respond to both the demands of citizens and the fewer dollars available. A combination of denial of new programmes and public sector pay austerity, with public education and use of community organizations is providing ways to stretch limited funds. The reality in many communities across the USA is that local government and its services will not be growing in the future. 相似文献
4.
5.
Sabha Kesraoui-Ouki Christopher R. Cheeseman Roger Perry 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1994,59(2):121-126
This paper assesses the potential of natural zeolite utilization as a low-cost ion-exchange and sorbent material in pollution control and recovery of metals. The improvement of the purity of natural zeolites coupled with their chemical modification capabilities in order to provide specific properties may provide a cost-effective alternative for the treatment of heavy metal contaminated soil and water. The application of natural zeolites in industrial pollution control is becoming important and the level of technical effort is increasingly expanding. The extent of application is unlikely to be related solely to their low cost, but also to improved properties and performance characteristics, which will advance the practical implementation of natural zeolites' technology. 相似文献
6.
Roger Norman Rothon Christopher Mark Liauw Graham Clayton Lees Wayne Christopher Edward Schofield 《The Journal of Adhesion》2002,78(7):603-628
The interaction of ammonium stearate (AS) and γ-aminopropyltriethoxysilane (APS) treatments with a magnesium hydroxide flame retardant filler and their effects on its use in an ethylene vinyl acetate copolymer compound have been investigated. The work has shown clear evidence of changes in the structure of the surface layers formed on the filler as the amount of additive is increased and the levels at which these occur can be correlated with theoretical monolayer quantities. Infrared (IR) spectroscopy data suggest that the stearate coating changes from a half salt to a full salt as the coating level is increased and that the APS coating on the filler initially has a significant bicarbonate content, presumably due to reaction with atmospheric carbon dioxide. The effect of coating level on the melt flow rate, insoluble matrix content, crystallisation behaviour, tensile properties, limiting oxygen index, and ageing of the filled compound has been studied. Distinct trends have been observed, many of which can be correlated with the structure of the filler surface layers. Of particular importance is the observation that, unlike APS, excess stearate appears to promote detrimental ageing effects. 相似文献
7.
9.
Toshiaki Nishihata Mayumi Ishizaka Sigeharu Yokohama Alice C. Martino Roger E. Gordon 《Drug development and industrial pharmacy》1993,19(20):2679-2698
The effects of particle size and food on the absolute bioavailability of U-78875 in dogs after oral administration of either a suspension or tablet dosage form were investigated. A reduction of particle size caused a significant increase in bioavailability along with an increase in dissolution rate. Additionally, both suspension and tablet dosage forms administered after food caused an increase in bioavailability. Thus, to accelerate drug dissolution, a reduction of U-78875 particle size from the unmilled state is important for the optimization of formulation compositions. To increase the bioavailability of U-78875, postprandial dosing should be considered. 相似文献
10.