全文获取类型
收费全文 | 2169篇 |
免费 | 127篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 31篇 |
综合类 | 8篇 |
化学工业 | 648篇 |
金属工艺 | 40篇 |
机械仪表 | 45篇 |
建筑科学 | 117篇 |
矿业工程 | 6篇 |
能源动力 | 69篇 |
轻工业 | 198篇 |
水利工程 | 20篇 |
石油天然气 | 7篇 |
无线电 | 182篇 |
一般工业技术 | 383篇 |
冶金工业 | 169篇 |
原子能技术 | 20篇 |
自动化技术 | 358篇 |
出版年
2023年 | 27篇 |
2022年 | 35篇 |
2021年 | 44篇 |
2020年 | 35篇 |
2019年 | 46篇 |
2018年 | 52篇 |
2017年 | 52篇 |
2016年 | 72篇 |
2015年 | 67篇 |
2014年 | 83篇 |
2013年 | 117篇 |
2012年 | 102篇 |
2011年 | 145篇 |
2010年 | 106篇 |
2009年 | 96篇 |
2008年 | 113篇 |
2007年 | 101篇 |
2006年 | 78篇 |
2005年 | 79篇 |
2004年 | 58篇 |
2003年 | 68篇 |
2002年 | 50篇 |
2001年 | 37篇 |
2000年 | 34篇 |
1999年 | 38篇 |
1998年 | 60篇 |
1997年 | 36篇 |
1996年 | 36篇 |
1995年 | 33篇 |
1994年 | 28篇 |
1993年 | 31篇 |
1992年 | 18篇 |
1991年 | 22篇 |
1990年 | 22篇 |
1989年 | 20篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 20篇 |
1985年 | 22篇 |
1984年 | 18篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 17篇 |
1977年 | 9篇 |
1976年 | 17篇 |
1974年 | 12篇 |
1973年 | 8篇 |
排序方式: 共有2301条查询结果,搜索用时 31 毫秒
181.
Combining scanning force and fluorescent microscopy allows simultaneous identification of labeled biomolecules and analysis of their nanometer level architectural arrangement. Fluorescent polystyrene nano-spheres were used as reliable objects for alignment of optical and topographic images. This allowed the precise localization of different fluorescence particles within complex molecular assemblies whose structure was mapped in nanometer detail topography. Our experiments reveal the versatility of this method for analysis of proteins and protein–DNA complexes. 相似文献
182.
Roland Waitz 《真空研究与实践》1999,11(2):79-82
Titanium is the first choice material for implants, chemical apparatus and in jewellery because of its mechanical, chemical and biological behaviour. The manufacturing of complicated formed parts can only be done with very expensive machines because of the high reactivity of the molten metal. The following paper describes a inexpensive proved technology for the production of titanium parts by an inductive heated casting machine. In comparison with conventional manufactured titanium parts the mechanical strength is only little reduced, therefore these parts could be used for nearly all applications. 相似文献
183.
Dipl.‐Ing. Volker Lenz Dipl.‐Ing. Marian Schenker Dipl.‐Ing. Christian Thiel Prof. Dr. Wolf‐Dietrich Einicke M.Sc. René Bindig Dr. rer. nat. Ulf Roland 《化学,工程师,技术》2011,83(3):371-376
In addition to the reduction of particulate matter, a catalytic supported emission reduction in small scale biomass combustion systems can also enable a conversion of toxic organic components into carbon dioxide and water. For catalyst investigations under practical conditions a special test facility was designed. The results show that products of incomplete combustion like carbon monoxide from stoves can be reduced by catalytic processes. Further developments and studies are necessary to achieve the targeted emission limits. 相似文献
184.
In this article, we propose methods that increase numerical efficiency of dynamic simulation of spatial multibody systems
described in absolute coordinates. The successive coordinate projection method efficiently stabilizes the system constraints
in the case when a non-minimal set of orientation coordinates is used to describe the orientation of bodies in space. The
new procedure of generation of Newton–Euler equations is shown in detail for systems with the most popular types of joints
(prismatic joint, revolute joint, etc.). The proposed algorithms were tested with models of a governor mechanism and Yamaha
YZF-R1 motorcycle engine. The simulation results show that the successive coordinate projection method is stable and can be
implemented for complex mechanical systems. 相似文献
185.
186.
Dirk Heinrich Roland Wursche 《中国眼镜科技杂志》2007,(7):109-111
眼镜的发展史,在某种程度上说,也就是新材料、新技术的发展史,正是由于新材料、新技术的不断涌现和改进,才推动了眼镜制造工艺的不断提高。 相似文献
187.
188.
The extraction of fluids from deformable underground formations has resulted in surface subsidence above the formation in several field cases. This paper demonstrates the necessity of using the coupled Biot’s equations for deformation-flow problems in deformable fluid-saturated porous media, particularly for problems involving fluid extraction or injection in underground formations. It is shown that it is not possible to decouple the fluid flow and deformation fields from Biot’s theory except for idealized one-dimensional cases where the total stresses are constant and the deformation mode can be assumed. The deficiencies of the uncoupled approach are also shown via an analysis of a case involving production-induced subsidence in a hydrocarbon field. An important prediction of the coupled analysis is the increase of pore pressure above the initial value during continuous withdrawal of fluids from deformable formations. 相似文献
189.
Roland Combescot 《Journal of Low Temperature Physics》2002,126(1-2):409-418
Recent progress toward degeneracy in ultracold Fermi gases raise hope to reach the BCS superfluuid transition in fermionic systems, the case of
6
Li being very favorable in view of its expected large and negative scattering length. We discuss the physical situation in the high density regime where the critical temperature is expected to be large. Indirect interaction due to the exchange of density fluctuations should play an important role. We discuss the physical points involved in our approximate calculation of the critical temperature which retains the same set of diagrams as in the paramagnon model. Near the instability threshold, the attractive interaction due to density fluctuations gives rise to a strong increase in the critical temperature, providing a clear signature of the existence of fluctuation induced interactions. 相似文献
190.
The results of applying three types of analytical mashing procedure—Institute of Brewing, European Brewery Convention, and Tepral systems—to the same malts are examined. Statistical correlations of the results are made. It is concluded that the main difference between the results of the Tepral method and the other two procedures is that the first gives much lower extracts when applied to malts which would be likely to be troublesome in the brewery, and is thus more discriminatory for these. The advantages of including sparging in an analytical method are pointed out. 相似文献