全文获取类型
收费全文 | 88723篇 |
免费 | 9434篇 |
国内免费 | 6230篇 |
专业分类
电工技术 | 7705篇 |
技术理论 | 3篇 |
综合类 | 8239篇 |
化学工业 | 11750篇 |
金属工艺 | 5523篇 |
机械仪表 | 6098篇 |
建筑科学 | 7314篇 |
矿业工程 | 2950篇 |
能源动力 | 2478篇 |
轻工业 | 7594篇 |
水利工程 | 2419篇 |
石油天然气 | 3788篇 |
武器工业 | 1193篇 |
无线电 | 10401篇 |
一般工业技术 | 9008篇 |
冶金工业 | 3361篇 |
原子能技术 | 1244篇 |
自动化技术 | 13319篇 |
出版年
2024年 | 526篇 |
2023年 | 1514篇 |
2022年 | 3184篇 |
2021年 | 4251篇 |
2020年 | 3246篇 |
2019年 | 2409篇 |
2018年 | 2472篇 |
2017年 | 2804篇 |
2016年 | 2591篇 |
2015年 | 3806篇 |
2014年 | 4699篇 |
2013年 | 5562篇 |
2012年 | 6798篇 |
2011年 | 7001篇 |
2010年 | 6435篇 |
2009年 | 6265篇 |
2008年 | 6486篇 |
2007年 | 5854篇 |
2006年 | 5373篇 |
2005年 | 4353篇 |
2004年 | 3263篇 |
2003年 | 2816篇 |
2002年 | 3261篇 |
2001年 | 2893篇 |
2000年 | 1940篇 |
1999年 | 1226篇 |
1998年 | 703篇 |
1997年 | 564篇 |
1996年 | 463篇 |
1995年 | 372篇 |
1994年 | 286篇 |
1993年 | 200篇 |
1992年 | 180篇 |
1991年 | 135篇 |
1990年 | 91篇 |
1989年 | 85篇 |
1988年 | 61篇 |
1987年 | 48篇 |
1986年 | 25篇 |
1985年 | 28篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 15篇 |
1980年 | 24篇 |
1979年 | 9篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1959年 | 12篇 |
1951年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Hsu‐Wei Fang Hsien‐Chieh Wang Teh‐Hua Tsai Wei‐Bor Tsai Shao‐Yi Hou Hsuan‐Liang Liu Wun‐Hsing Lee Yung‐Chang Lu Chun‐Hsiung Huang 《应用聚合物科学杂志》2008,108(4):2428-2437
Wear of ultrahigh‐molecular‐weight polyethylene (UHMWPE) and wear‐particle‐induced osteolysis and bone resorption are the major factors causing the failure of total joint replacements. It is feasible to improve the lubrication and reduce the wear of artificial joints. We need further understanding of the lubrication mechanism of the synovial fluid. The objective of this study is to evaluate the lubricating ability of three major components in the synovial fluid: albumin, globulin, and phospholipids. An accelerated wear testing procedure in which UHMWPE is rubbed against a microfabricated surface with controlled asperities has been developed to evaluate the lubrication behavior. An analysis of the wear particle dimensions and wear amount of the tests has provided insights for comparing their lubrication performance. It is concluded that the presence of biomolecules at the articulating interface may reduce friction. A higher concentration of a biological lubricant leads to a decrease in the wear particle width. In addition, in combination with the wear results and mechanical analysis, the roles of individual biomolecules contributing to friction and wear at the articulating interface are discussed. These results can help us to identify the role of the biomolecules in the boundary lubrication of artificial joints, and further development of lubricating additives for artificial joints may be feasible. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
22.
Effect of Li+ ions on structure,properties, and actuation of cellulose electro‐active paper actuator
We have reported an electro‐active paper actuator from regenerated cellulose. After dissolving cellulose fibers with a solution of lithium chloride in N,N‐dimethylacetamide, cellulose was regenerated by combining distillation of cellulose solution along with washing with the mixture of deionized water, isopropyl alcohol, and running water. However, the effect of Li+ ions on structure, properties, and the actuation behavior of the actuator was not studied. This article describes the changes in these parameters when the Li+ ions are removed by subjecting it to different running water exposure time. The structure and properties of cellulose electro‐active paper and its actuation behavior were studied. As Li+ ions content reduced from 4354.17 to 10.26 ppm by increasing the exposure time of running water, crystallinity, Young's modulus, and bending displacement decreased. Details about the investigation have been explained. This elimination of ions is important to increase the piezoelectric effect in EAPap by decreasing the ion migration effect. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
23.
24.
25.
Transdermal absorption of zidovudine (AZT) from an ethanol-isopropyl myristate (IPM) mixed system was examined in rats. For comparison of bioavailability (BA) after topical applications, 0.25 ml of the ethanol/IPM system containing 40% ethanol and 60 mM AZT was applied as a standard formulation. Values of the area under the plasma concentration-time curves of AZT for 8 hr (AUC0-8), as indices of BA, following application of various formulations were compared with that of the standard formulation. Then the influence of content of the drug and ethanol, and application volume of the system was evaluated. BA was effectively improved only when the total amount of ethanol applied on the skin was increased. On the other hand, simultaneous transdermal application of AZT and probenecid increased the AU0-8, of AZT without necessitating the increase in ethanol content in the formulation. In addition, coadministered probenecid improved cerebrospinal fluid/plasma concentration ratio of AZT. 相似文献
26.
刘品意 《消防技术与产品信息》2005,(2):12-14
通过对西部某小城市的住宅消防设施建设和管理现状的调查 ,反映了占西部绝大部分城市面积的中小城镇的住宅消防设施十分令人担忧的现状 ,分析了造成这一现状的原因 ,提出了解决这一问题的建设管理思路 相似文献
27.
观赏草在庭园中的设计与应用 总被引:2,自引:0,他引:2
观赏草以其灵动的景观特质,草类特有的自然色调,飘逸的质感越来越受到设计师们的青睐,用于焦点、绿蒿、花镜、镶边均有不凡的表现,虽为草类,却有着灌木的功能。 相似文献
28.
29.
30.
Applied Intelligence - Personnel performance is a key factor to maintain core competitive advantages. Thus, predicting personnel future performance is a significant research domain in human... 相似文献