全文获取类型
收费全文 | 1075篇 |
免费 | 51篇 |
专业分类
电工技术 | 10篇 |
综合类 | 1篇 |
化学工业 | 294篇 |
金属工艺 | 33篇 |
机械仪表 | 49篇 |
建筑科学 | 57篇 |
矿业工程 | 1篇 |
能源动力 | 35篇 |
轻工业 | 56篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 68篇 |
一般工业技术 | 225篇 |
冶金工业 | 79篇 |
原子能技术 | 4篇 |
自动化技术 | 206篇 |
出版年
2024年 | 4篇 |
2023年 | 19篇 |
2022年 | 23篇 |
2021年 | 49篇 |
2020年 | 38篇 |
2019年 | 47篇 |
2018年 | 33篇 |
2017年 | 20篇 |
2016年 | 36篇 |
2015年 | 39篇 |
2014年 | 41篇 |
2013年 | 62篇 |
2012年 | 70篇 |
2011年 | 87篇 |
2010年 | 64篇 |
2009年 | 51篇 |
2008年 | 46篇 |
2007年 | 61篇 |
2006年 | 41篇 |
2005年 | 38篇 |
2004年 | 24篇 |
2003年 | 14篇 |
2002年 | 26篇 |
2001年 | 11篇 |
2000年 | 13篇 |
1999年 | 9篇 |
1998年 | 31篇 |
1997年 | 19篇 |
1996年 | 12篇 |
1995年 | 17篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有1126条查询结果,搜索用时 0 毫秒
151.
152.
Implementing NLP projects for noncentral languages: instructions for funding bodies, strategies for developers 总被引:1,自引:1,他引:0
This research begins by distinguishing a small number of “central” languages from the “noncentral languages”, where centrality
is measured by the extent to which a given language is supported by natural language processing tools and research. We analyse
the conditions under which noncentral language projects (NCLPs) and central language projects are conducted. We establish
a number of important differences which have far-reaching consequences for NCLPs. In order to overcome the difficulties inherent
in NCLPs, traditional research strategies have to be reconsidered. Successful styles of scientific cooperation, such as those
found in open-source software development or in the development of the Wikipedia, provide alternative views of how NCLPs might
be designed. We elaborate the concepts of free software and software pools and argue that NCLPs, in their own interests, should
embrace an open-source approach for the resources they develop and pool these resources together with other similar open-source
resources. The expected advantages of this approach are so important that we suggest that funding organizations put it as
sine qua non condition into project contracts.
All trademarks are hereby acknowledged. 相似文献
153.
154.
Summary p-Aminobenzoylcaprolactam has been polymerized anionically in a two-step process to produce aramide-amide copolymers. Both drawn fibers and unoriented films may be produced using this method. The samples were characterized using FTIR, solution NMR, thermal analysis, viscosity, and mechanical testing. FTIR and NMR revealed the incorporation of both the aramid and amide linkages into the polymer backbone. TGA results gave a lower decomposition temperature than that of both aramide and nylon 6 materials. Intrinsic viscosities averaged 0.5 dL/g for the drawn copolymer samples polymerized by the di-functional initiator. Light microscopy displayed crystalline domains that did not appear to melt even up to 300°C. Mechanical testing showed that the initial moduli of drawn fiber samples to be in the range of 30–80 MPa, while homopolymers of nylon 6 and p-benzamide possessed values of 25 MPa and 2.70×103 MPa, respectively. 相似文献
155.
Baumert M Baier V Truebner S Schirdewan A Voss A 《IEEE transactions on bio-medical engineering》2005,52(12):2112-2115
Autonomic cardiovascular control involves complex interactions of heart rate and blood pressure. In patients with dilated cardiomyopathy (DCM), this control is impaired and parameters for its quantification might be of prognostic importance. In this paper, we introduce methods based on joint symbolic dynamics (JSD) for the enhanced analysis of heart rate and blood pressure interactions. To assess the coarse-grained dynamics beat-to-beat changes of heart rate and blood pressure are encoded in symbol strings. Subsequently, the distribution properties of short symbol sequences (words) as well as the scaling properties of the whole symbol string are assessed. The comparison of joint symbolic heart rate and blood pressure dynamics in DCM (n = 75) with those in healthy controls (n = 75) showed significant changes. Both, the distribution of words and the scaling properties indicate a loss in heart rate dynamics associated with blood pressure regulation in DCM. In conclusion, the analyses of short- and long-term JSDs provide insights into complex physiological heart rate and blood pressure interactions and furthermore reveal patho-physiological cardiovascular control in DCM. 相似文献
156.
de Jesus DP Brito-Neto JG Richter EM Angnes L Gutz IG do Lago CL 《Analytical chemistry》2005,77(2):607-614
The use of two additional reservoirs to accommodate the electrodes of the power source is proposed to improve the stability of the running electrolyte in capillary electrophoresis. The basic idea is to use salt bridges to connect those reservoirs to the ones containing the capillary ends. Although simple, there are several issues that can be considered in the design and implementation of such system in order to prevent undesired transference of material between the electrolysis and the main reservoirs. The use of a sealed electrolysis reservoir without a gas phase, the use of materials that ensure volume stability, and the use of bridges as long as possible are three basic directions. A compromise is involved in the dimensions of the sectional area of the bridge, because a small area diminishes the amount of a species transferred by diffusion but leads to an undesirable increase of the electrical field during the electrophoretic running. Thus, a bridge composed of a main wide-bore tube connected to a small-bore capillary seems to give the best performance for practical use. A simple electrolysis-separated system was adapted to a preexisting capillary electrophoresis system, and its performance was evaluated with a mixture of tartaric, malic, and succinic acids that was separated in sodium benzoate solution (pH 5.5) using the original equipment and the modified one. Due to the water electrolysis and the small buffering capacity of the electrolyte, there was a significant pH change and consequently changes in the effective mobilities of the analytes and loss of resolution after a few runs using the original equipment. Using the electrolysis-separated system, no significant change in the migration time and resolution was observed even after 15 runs. Besides the freedom to prepare running electrolytes with electroactive species or unbuffered solution, high throughput and the use of small reservoirs, such as the ones used in microfluidic devices, are the main advantages of the system. 相似文献
157.
Microsatellite genotyping was evaluated as a potential tool for DNA-based tracing of ground beef product. DNA from mixtures containing different numbers of individuals was analysed with a set of cattle microsatellite markers frequently used for parentage testing. As samples contained DNA from several animals, the microsatellite markers showed multiple peaks. The method could distinguish between mixtures containing equal amounts of meat from three different individuals, meat from three individuals mixed in different proportions, ground beef mixtures purchased in different cities, and different batches of ground beef patties. Limitations occurred when batches contained large numbers of individuals (>10) and different batches used meat from the same individuals. We conclude that DNA microsatellites may be useful for DNA traceability of ground beef mixtures prepared from less than 10 individuals, but where larger numbers of animals contribute to a mixture the method is not consistently accurate. 相似文献
158.
The changes of pressure and activity coefficients with component densities are expressed in terms of statistical mechanical direct correlation function 相似文献
159.
Dr.-Ing. Dierk Raabe Dr.-Ing. Martin Hölscher Dr.-Ing. Mathias Dubke Dipl.-Ing. Karl-Heinz Hanke Dr.-Ing. Herbert Pfeifer Professor Dr. rer. nat. Dr. h.c. Kurt Lücke 《国际钢铁研究》1993,64(7):359-363
The textures and the mechanical properties of a strip cast, cold rolled and recrystallized ferritic stainless steel with 16% Cr have been investigated and compared to conventionally processed hot band. The strip cast initial material exposed three improvements. First, the textures were weaker and more homogeneous through the sheet thickness. Second, it revealed a higher Lankfort value and third, the complete elimination of the ridging phenomenon. 相似文献
160.
Friction is one of the most important parameters in sheet metal forming. Friction conditions are influenced by the texture
of the sheet surface, by the surface or coating of the tools and by the lubrication. The aluminium alloy AA 5182 with EDT
surface has been studied and tested at various angles between rolling and sliding direction. The friction behaviour observed
in experiments at different normal pressures based on Coulomb’s friction law are shown and discussed in this article. Moreover,
local surface topography and lubricant distribution in the contact area are described. 相似文献