全文获取类型
收费全文 | 822篇 |
免费 | 46篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 293篇 |
金属工艺 | 10篇 |
机械仪表 | 16篇 |
建筑科学 | 15篇 |
能源动力 | 36篇 |
轻工业 | 90篇 |
水利工程 | 3篇 |
石油天然气 | 4篇 |
无线电 | 75篇 |
一般工业技术 | 125篇 |
冶金工业 | 49篇 |
原子能技术 | 4篇 |
自动化技术 | 143篇 |
出版年
2023年 | 7篇 |
2022年 | 40篇 |
2021年 | 60篇 |
2020年 | 31篇 |
2019年 | 26篇 |
2018年 | 29篇 |
2017年 | 24篇 |
2016年 | 37篇 |
2015年 | 28篇 |
2014年 | 44篇 |
2013年 | 56篇 |
2012年 | 60篇 |
2011年 | 55篇 |
2010年 | 44篇 |
2009年 | 40篇 |
2008年 | 27篇 |
2007年 | 27篇 |
2006年 | 18篇 |
2005年 | 16篇 |
2004年 | 16篇 |
2003年 | 19篇 |
2002年 | 14篇 |
2001年 | 12篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 19篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1971年 | 3篇 |
1933年 | 2篇 |
1916年 | 2篇 |
排序方式: 共有868条查询结果,搜索用时 15 毫秒
1.
2.
Photonic Network Communications - Optical packet switching is a prominent technology proposing not only a reduction in the energy consumption by the elimination of numerous... 相似文献
3.
Vitamin D Compounds PRI-2191 and PRI-2205 Enhance Anastrozole Activity in Human Breast Cancer Models
Beata Filip-Psurska Mateusz Psurski Artur Anisiewicz Patrycja Libako Ewa Zbrojewicz Magdalena Maciejewska Micha Chodyski Andrzej Kutner Joanna Wietrzyk 《International journal of molecular sciences》2021,22(5)
1,25-Dihydroxycholecalciferol, the hormonally active vitamin D3 metabolite, is known to exhibit therapeutic effects against breast cancer, mainly by lowering the expression of estrogen receptors and aromatase activity. Previously, the safety of the vitamin D active metabolite (24R)-1,24-dihydroxycholecalciferol (PRI-2191) and 1,25(OH)2D3 analog PRI-2205 was tested, and the in vitro activity of these analogs against different cancer cell lines was studied. We determined the effect of the two vitamin D compounds on anastrozole (An) activity against breast cancer based on antiproliferative activity, ELISA, flow cytometry, enzyme inhibition potency, PCR, and xenograft study. Both the vitamin D active metabolite and synthetic analog regulated the growth of not only estrogen receptor-positive cells (T47D and MCF-7, in vitro and in vivo), but also hormone-independent cancer cells such as SKBR-3 (HER-2-positive) and MDA-MB-231 (triple-negative), despite their relatively low VDR expression. Combined with An, PRI-2191 and PRI-2205 significantly inhibited the tumor growth of MCF-7 cells. Potentiation of the antitumor activity in combined treatment of MCF-7 tumor-bearing mice is related to the reduced activity of aromatase by both An (enzyme inhibition) and vitamin D compounds (switched off/decreased aromatase gene expression, decreased expression of other genes related to estrogen signaling) and by regulation of the expression of the estrogen receptor ERα and VDR. 相似文献
4.
Further evidence was delivered that certain impurities, which could be contained in MgO samples, might be responsible for observed variability in MgO basicity and catalytic performance in oxidative coupling of methane. The surface basicity/base strength distribution of a series of MgO samples containing or not containing Ca and Na impurities was determined by a temperature-programmed desorption of CO2. It was revealed that samples containing Ca and Na impurities have much more medium, strong and very strong basic sites. The surface basicity of MgO samples containing added alkali or alkaline earth compounds or water was characterized by a test reaction of transformation of 2-butanol. It was confirmed that the introduction of these compounds to a pure MgO enhanced both its basicity and activity in oxidative coupling of methane. 相似文献
5.
Maciej Winiewski Artur Jakubiak Jan Szymanowski 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,63(3):209-214
Decyl isonicotiniate and decyl nicotiniate permit a rapid extraction of palladium(II) from its hydrochloride solutions. Decyl picoliniate is not a suitable extractant. 4-Octylphenylamine can act as a phase transfer catalyst when its concentration in the organic phase is at least 2·5 × 10?4 M . It seems that the interfacial adsorption of pyridine carboxylates and of 4-octylphenylamine is not the decisive phenomenon in palladium(II) extraction. The negligible protonation of the pyridine-type extractants and the phase transfer catalysis explains well the quick extraction of palladium(II) with the commercial and highly hydrophobic extractant ACORGA CLX-50. 相似文献
6.
Artur Lugmayr Bjoern Stockleben Yaning Zou Sonja Anzenhofer Mika Jalonen 《Multimedia Tools and Applications》2014,71(1):119-157
“Design Thinking” – a cross-disciplinary and user centered method – is an approach towards the discovery of solutions and sparks innovative thinking in many ways. It also can be argued, that designers put themselves in the place of the user rather than co-creating with the consumer. Innovation is one of the current keywords across many industries, and many attempt to find new solutions to daily problems. Design Thinking as method allows to understand user needs and understand their principle problems in daily life. The design process uses intensive collaboration in cross-disciplinary settings and is divided into the exploration of the problem space and the solution space to achieve new ways of solving existing problems. Design Thinking has to integrate into the innovation process and into organizational structures right from the beginning. It constitutes a complement to classical analytical processes for problems that require lateral, not linear thinking. This article reviews the practical application of this energetic methodology in the academic context and presents some hands-on examples. The course series has been established by the Entertainment and Media Management Lab. (EMMi Lab.) at the Tampere University of Technology (TUT) and was held in cooperation with students from the University of Tampere (UTA), and the Tampere University of Applied Sciences (TAMK). One course has been held in cooperation with the University of Applied Sciences Magdeburg-Stendal, Germany. This article describes how to train students especially with strong technical background and analytical mind-sets in the development of innovations in the field of media, foster creative thinking, and achieve problem solutions beyond the current state of the art. We present the basic curriculum, course structure, goals & objectives, applied methods, settings, and theoretical aspects of Design Thinking. Our experience and reflections on conducting the courses concludes this article. The article shall be an introductory guide for anyone who intends to organize a similar course in the university context. 相似文献
7.
Artur Jeż 《Theory of Computing Systems》2014,55(4):685-718
In this paper, a compressed membership problem for finite automata, both deterministic (DFAs) and non-deterministic (NFAs), with compressed transition labels is studied. The compression is represented by straight-line programs (SLPs), i.e. context-free grammars generating exactly one string. A novel technique of dealing with SLPs is employed: the SLPs are recompressed, so that substrings of the input word are encoded in SLPs labelling the transitions of the NFA (DFA) in the same way, as in the SLP representing the input text. To this end, the SLPs are locally decompressed and then recompressed in a uniform way. Furthermore, in order to reflect the recompression in the NFA, we need to modify it only a little, in particular its size stays polynomial in the input size. Using this technique it is shown that the compressed membership for NFA with compressed labels is in NP, thus confirming the conjecture of Plandowski and Rytter (Jewels Are Forever, pp. 262–272, Springer, Berlin, 1999) and extending the partial result of Lohrey and Mathissen (in CSR, LNCS, vol. 6651, pp. 275–288, Springer, Berlin, 2011); as this problem is known to be NP-hard (in Plandowski and Rytter, Jewels Are Forever, pp. 262–272, Springer, Berlin, 1999), we settle its exact computational complexity. Moreover, the same technique applied to the compressed membership for DFA with compressed labels yields that this problem is in P, and this problem is known to be P-hard (in Markey and Schnoebelen, Inf. Process. Lett. 90(1):3–6, 2004; Beaudry et al., SIAM J. Comput. 26(1):138–152, 1997). 相似文献
8.
9.
10.
Juan de Lara Esther Guerra Artur Boronat Reiko Heckel Paolo Torrini 《Software and Systems Modeling》2014,13(1):209-238
Graph transformation is being increasingly used to express the semantics of domain-specific visual languages since its graphical nature makes rules intuitive. However, many application domains require an explicit handling of time to accurately represent the behaviour of a real system and to obtain useful simulation metrics to measure throughputs, utilization times and average delays. Inspired by the vast knowledge and experience accumulated by the discrete event simulation community, we propose a novel way of adding explicit time to graph transformation rules. In particular, we take the event scheduling discrete simulation world view and provide rules with the ability to schedule the occurrence of other rules in the future. Hence, our work combines standard, efficient techniques for discrete event simulation (based on the handling of a future event set) and the intuitive, visual nature of graph transformation. Moreover, we show how our formalism can be used to give semantics to other timed approaches and provide an implementation on top of the rewriting logic system Maude. 相似文献