全文获取类型
收费全文 | 1695篇 |
免费 | 79篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 14篇 |
化学工业 | 525篇 |
金属工艺 | 17篇 |
机械仪表 | 27篇 |
建筑科学 | 73篇 |
矿业工程 | 1篇 |
能源动力 | 55篇 |
轻工业 | 288篇 |
水利工程 | 7篇 |
石油天然气 | 4篇 |
无线电 | 106篇 |
一般工业技术 | 301篇 |
冶金工业 | 102篇 |
原子能技术 | 6篇 |
自动化技术 | 252篇 |
出版年
2023年 | 19篇 |
2022年 | 45篇 |
2021年 | 61篇 |
2020年 | 44篇 |
2019年 | 48篇 |
2018年 | 36篇 |
2017年 | 42篇 |
2016年 | 45篇 |
2015年 | 49篇 |
2014年 | 70篇 |
2013年 | 132篇 |
2012年 | 121篇 |
2011年 | 151篇 |
2010年 | 76篇 |
2009年 | 94篇 |
2008年 | 80篇 |
2007年 | 93篇 |
2006年 | 67篇 |
2005年 | 51篇 |
2004年 | 48篇 |
2003年 | 54篇 |
2002年 | 36篇 |
2001年 | 20篇 |
2000年 | 20篇 |
1999年 | 33篇 |
1998年 | 41篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 22篇 |
1994年 | 17篇 |
1993年 | 18篇 |
1992年 | 14篇 |
1991年 | 2篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 2篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有1778条查询结果,搜索用时 15 毫秒
1.
2.
Alberto Ballesteros Ester Laguna-Gutierrez Paula Cimavilla-Roman Maria Luisa Puertas Antonio Esteban-Cubillo Julio Santaren Miguel Angel Rodriguez-Perez 《应用聚合物科学杂志》2021,138(46):51373
In the present work blends of polystyrene (PS) with sepiolites have been produced using a melt extrusion process. The dispersion degree of the sepiolites in the PS has been analyzed by dynamic shear rheology and X-ray micro-computed tomography. Sepiolites treated with quaternary ammonium salts (O-QASEP) are better dispersed in the PS matrix than natural sepiolites (N-SEP) or sepiolites organo-modified with silane groups (O-SGSEP). A percolated network is obtained when using 6.0 wt% of O-QASEP, 8.0 wt% of N-SEP and 10.0 wt% of O-SGSEP. It has been shown that multiple extrusion processes have a negative effect on the polymer architecture. They produce a reduction in the length of the polymeric chains, and they do not lead to a better dispersion of the particles in the polymer matrix. Foams have been produced using a gas dissolution foaming process, where a strong effect of the dispersion degree on the cellular structure of the different foams was found. The effects on the cellular structure obtained by using different types of sepiolites, different contents of sepiolites and different extrusion conditions have been analyzed. The foams produced with the formulations containing O-QASEP present the lowest cell size and the most homogeneous cellular structures. 相似文献
3.
4.
T Ojasoo E Bignon A Crastes de Paulet JC Doré J Gilbert JF Miquel M Pons JP Raynaud 《Canadian Metallurgical Quarterly》1993,44(3):239-250
A multivariate statistical method, correspondence factorial (CF) analysis, was used to examine the correlations among the protein binding and cell proliferation effects of a series of 36 di- and triphenylethylenes (DPEs and TPEs). The analysis was applied to a study which measured their competition for estradiol binding to cytosol estrogen receptor (ER), their influence on protein kinase C (PKC) activity under different conditions of enzyme activation, their ability to promote the growth of a breast cancer cell line and to inhibit growth at high concentrations (cytotoxicity). The CF analysis revealed several levels of correlation. First, it distinguished those molecules within the population that stimulated rather than inhibited PKC activity. Second, it made apparent a strong correlation between cytotoxicity and inhibition of Ca++ and phosphatidylserine-dependent PKC activity, which was most marked when the enzyme had been activated by diacylglycerol indicating that PKC inhibition under physiological conditions might contribute to the overall cytotoxicity of these compounds. Third, a lower level of correlation was established between competition for ER binding and cytotoxicity. Taken together, the results suggest that MCF7 cells might be most sensitive to a cytotoxic effect of TPEs (via PKC and other targets) when they at the same time decrease estrogen-stimulated proliferation via an ER-mediated antiestrogenic effect. 相似文献
5.
Paul W. Angel Chandra S. Ray Delbert E. Day 《Journal of the American Ceramic Society》1986,69(6):134-C
6.
Imperfection in information can be considered a crosscutting concern that manifests itself in diverse kinds of imprecision, uncertainty, or inconsistency in the data models of a software system. The extension of existing programming and querying interfaces for the different aspects of information imperfection requires a proper modularization of the different concerns of numerical imprecision handling, so that the extensions do not interfere with existing programming practices and do not obscure the original design. Aspect‐oriented design (AOD) enables such a form of nonintrusive extensions to be added to existing software libraries, clearly separating fuzziness or other imperfections in data as a differentiated concern that can be considered from the early phases of development. In this article, a general framework for aspect‐based extension of data models and fuzzy databases is described, and some design and implementation issues of such AOD‐based extensions on OJB database libraries are described as a case study. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1199–1216, 2006. 相似文献
7.
Gerardo Gabriel Acosta Miguel Angel Mayosky José Maria Catalfo 《Applied Intelligence》1994,4(1):53-66
This article proposes a scheme for the on-line adjustment of three mode controller settings based on experimental measurements of closed-loop performance. It uses a recently developed heuristic tuning procedure to identify estimated process parameters. This method may give rise to conflicting estimates. Fuzzy Set theory is applied to manage the situation in terms of a fuzzy conjunction to combine the various estimates. PID control was chosen because of its wide use in the industrial environment due to driving simplicity and robustness. The article shows design, development, and computer simulation aspects. 相似文献
8.
德国的珠宝设计散发着一种典型的德国气质,就像德国的宝马、奔驰一样,远远看来,没有特别的装饰,朴实略显厚重,但是,近距离观察,就会因为无瑕疵的工艺和细节的经典处理而感动,心跳不已。德国人就是这样,用他们的工艺撼动人类,而不由得你不赞叹:精工亦是艺术。 相似文献
9.
This paper focuses on the harmonization of feed-in laws in the European Union as a support mechanism for the promotion of renewable electricity. In particular, it proposes a methodology for harmonization based on a feed-in law with a modular and transparent premium for renewable electricity producers. This premium considers technology costs, some grid services, political incentives and national priorities. The proposed approach includes flexibility mechanisms to update and revise premiums, to avoid windfall profits for producers, and to share technology innovation benefits with electricity consumers while maintaining incentives for innovation. Our approach is based on the review of the main features of the German and Spanish feed-in laws, and takes into account other necessary considerations for harmonization, such as grid access, funding, definitions and standards, ownership of rights derived from renewables, and exceptions for small non-commercial producers and energy-intensive industries. 相似文献
10.