全文获取类型
收费全文 | 2972篇 |
免费 | 292篇 |
国内免费 | 138篇 |
专业分类
电工技术 | 200篇 |
综合类 | 282篇 |
化学工业 | 145篇 |
金属工艺 | 312篇 |
机械仪表 | 734篇 |
建筑科学 | 214篇 |
矿业工程 | 94篇 |
能源动力 | 237篇 |
轻工业 | 109篇 |
水利工程 | 62篇 |
石油天然气 | 94篇 |
武器工业 | 46篇 |
无线电 | 119篇 |
一般工业技术 | 512篇 |
冶金工业 | 88篇 |
原子能技术 | 37篇 |
自动化技术 | 117篇 |
出版年
2024年 | 17篇 |
2023年 | 46篇 |
2022年 | 81篇 |
2021年 | 103篇 |
2020年 | 110篇 |
2019年 | 76篇 |
2018年 | 87篇 |
2017年 | 91篇 |
2016年 | 126篇 |
2015年 | 102篇 |
2014年 | 194篇 |
2013年 | 158篇 |
2012年 | 205篇 |
2011年 | 247篇 |
2010年 | 158篇 |
2009年 | 173篇 |
2008年 | 128篇 |
2007年 | 177篇 |
2006年 | 167篇 |
2005年 | 142篇 |
2004年 | 115篇 |
2003年 | 120篇 |
2002年 | 87篇 |
2001年 | 82篇 |
2000年 | 79篇 |
1999年 | 49篇 |
1998年 | 46篇 |
1997年 | 47篇 |
1996年 | 35篇 |
1995年 | 36篇 |
1994年 | 26篇 |
1993年 | 13篇 |
1992年 | 19篇 |
1991年 | 12篇 |
1990年 | 16篇 |
1989年 | 5篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1958年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有3402条查询结果,搜索用时 31 毫秒
1.
2.
针对当前KJS-Y系列降尘器效率低的问题,通过调整叶轮轴向间隙与径向间隙参数,分别对不同安装参数的降尘器进行数值模拟,通过数值模拟分析特定截面压力分布情况,确定了叶轮最佳安装参数,大大提高了降尘器的工作效率,同时降低了设计成本。 相似文献
3.
Dr. Li Di Prof. Per Artursson Dr. Alex Avdeef Prof. Leslie Z. Benet Prof. J. Brian Houston Dr. Manfred Kansy Edward H. Kerns Prof. Hans Lennernäs Dr. Dennis A. Smith Prof. Kiyohiko Sugano 《ChemMedChem》2020,15(20):1862-1874
Passive permeability is a key property in drug disposition and delivery. It is critical for gastrointestinal absorption, brain penetration, renal reabsorption, defining clearance mechanisms and drug-drug interactions. Passive diffusion rate is translatable across tissues and animal species, while the extent of absorption is dependent on drug properties, as well as in vivo physiology/pathophysiology. Design principles have been developed to guide medicinal chemistry to enhance absorption, which combine the balance of aqueous solubility, permeability and the sometimes unfavorable compound characteristic demanded by the target. Permeability assays have been implemented that enable rapid development of structure-permeability relationships for absorption improvement. Future advances in assay development to reduce nonspecific binding and improve mass balance will enable more accurately measurement of passive permeability. Design principles that integrate potency, selectivity, passive permeability and other ADMET properties facilitate rapid advancement of successful drug candidates to patients. 相似文献
4.
5.
Y. N. Lenets 《Fatigue & Fracture of Engineering Materials & Structures》1997,20(2):249-256
Abstract— The behaviour of fatigue cracks in an Al-alloy under cyclic compression, either with or without overloads, was studied. For constant-amplitude compressive cycling, a non-catastrophic (saturation) character of the fatigue crack behaviour was confirmed, with the final depth of a crack depending on the applied load level. Single (tensile or compressive) intermittent overloads were shown to re-activate a previously arrested crack while reversed (tensile—compressive or compressive—tensile) ones were also shown to maintain continual fatigue crack extension under otherwise fully compressive cycling. 相似文献
6.
7.
A framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance 总被引:7,自引:0,他引:7
Mechanical mechanisms with clearance abound in technological fields such as robotics, machine and steam turbine industry. The dynamic performance of these mechanisms in working condition can be achieved provided that the effects of the different on the mechanisms (such as mechanism dynamics, technological effects and thermal behaviour) are thoroughly understood. Virtual prototyping provides an integration of multi-domain dynamic simulation for the design and analysis process. In the current paper, a framework of virtual prototyping environment for the design and analysis of mechanical mechanism with clearance is presented. A case study with such a simulation strategy is studied for the optimum design and analysis of the technological parameter. 相似文献
9.
10.