全文获取类型
收费全文 | 1397篇 |
免费 | 35篇 |
专业分类
电工技术 | 22篇 |
化学工业 | 311篇 |
金属工艺 | 30篇 |
机械仪表 | 26篇 |
建筑科学 | 57篇 |
矿业工程 | 23篇 |
能源动力 | 15篇 |
轻工业 | 125篇 |
水利工程 | 21篇 |
石油天然气 | 3篇 |
无线电 | 90篇 |
一般工业技术 | 224篇 |
冶金工业 | 262篇 |
原子能技术 | 13篇 |
自动化技术 | 210篇 |
出版年
2022年 | 32篇 |
2021年 | 26篇 |
2020年 | 20篇 |
2019年 | 19篇 |
2018年 | 14篇 |
2017年 | 15篇 |
2016年 | 37篇 |
2015年 | 25篇 |
2014年 | 45篇 |
2013年 | 59篇 |
2012年 | 67篇 |
2011年 | 69篇 |
2010年 | 55篇 |
2009年 | 54篇 |
2008年 | 58篇 |
2007年 | 60篇 |
2006年 | 41篇 |
2005年 | 35篇 |
2004年 | 39篇 |
2003年 | 29篇 |
2002年 | 41篇 |
2001年 | 19篇 |
2000年 | 26篇 |
1999年 | 30篇 |
1998年 | 71篇 |
1997年 | 44篇 |
1996年 | 26篇 |
1995年 | 19篇 |
1994年 | 23篇 |
1993年 | 25篇 |
1992年 | 14篇 |
1991年 | 17篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 22篇 |
1987年 | 19篇 |
1986年 | 8篇 |
1985年 | 14篇 |
1984年 | 16篇 |
1983年 | 14篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 14篇 |
1976年 | 9篇 |
1975年 | 13篇 |
1972年 | 10篇 |
1968年 | 7篇 |
排序方式: 共有1432条查询结果,搜索用时 9 毫秒
51.
Huriye Akdas-Kilig Jean-Pierre MalvalFabrice Morlet-Savary Anu SinghLoic Toupet Isabelle Ledoux-RakJoseph Zyss Hubert Le Bozec 《Dyes and Pigments》2012,92(1):681-688
Two new 4,4′-bis(donor)-6,6′-diphenyl- 2,2′-bipyridine ligands and their corresponding D2d (CuI, AgI, ZnII) octupolar metal complexes were synthesized, and their linear and nonlinear optical properties were investigated. A single crystal X-ray structure was also determined for the bis[4,4′-bis(diethylaminostyryl)-6,6′-diphenyl-bipyridine]copper(I) complex, which revealed a distorded pseudo-tetrahedral geometry. Molecular second-order nonlinear optical properties were determined for the complexes using the Harmonic Light Scatterring technique at 1.91 μm. These metallo-chromophores display large first hyperpolarizabilities β1.91 in the range of 211-340 × 10−30 esu, which increase with the Lewis acidity of the metal ion. The two-photon absorption properties of the bipyridyl ligands and related complexes were determined using either the two-photon emission method for fluorescent compounds or the open aperture Z-scan technique for non emissive ones. The complexes display red-shifted two-photon absorption bands compared to their metal-ion free chromophores, as well as a large increase of the maximum two-photon absorption cross-sections. 相似文献
52.
53.
54.
55.
56.
J. Vogel H.-J. Feige J. Saupe S. Schubert J. Grimm 《Microsystem Technologies》2014,20(10-11):1975-1979
In addition to the development of materials and technologies for smart HARMST applications the analysis of the thermo-mechanical material properties seems to be necessary to describe the photosensitive polymers applied. To do this, a microtensile analysis system has been developed to determine stress–strain curves, Young’s modulus and Poisson’s ratio. The results are compared with those of dynamical mechanical thermal analysis and discussed. 相似文献
57.
Renata Rybakiewicz David Djurado Hubert Cybulski Ewelina Dobrzynska Irena Kulszewicz-Bajer Damien Boudinet Jean-Marie Verilhac Malgorzata Zagorska Adam Pron 《Synthetic Metals》2011,161(15-16):1600-1610
New solution processable organic semiconductors, consisting of pyrromelitic, naphthalene or perylene bisimide core and triarylamine N-substituents, have been synthesized. All three compounds are electrochemically active and undergo quasi-reversible oxidation and reduction as evidenced by cyclic voltammetry investigations. The oxidation process involves the transformation of the triarylamine substituents into radical cations as proven spectroscopically and spectroelectrochemically. The reduction process occurs at the arylene bisimide core leading to the formation of a radical anion and eventually a dianion in the second step. These findings are in perfect agreement with the DFT calculations which show that in the synthesized molecules the HOMO orbital is located on the triarylamine moiety whereas the LUMO one on the bisimide core. In all molecules studied the electrochemically determined ionization potential (IP) is slightly higher than 5.0 eV whereas in naphthalene and perylene derivatives the electron affinity (EA) is close to ?3.9 eV. These values fulfill the requirements for n-type (electron) semiconductors in air operating n-channel field effect transistors (FETs) as well as for p-type (hole) conductors in p-channel FETs. To verify whether the newly synthesized compounds exhibit the expected electrical transport properties all organic (CYTOP dielectric) test transistors were fabricated. All three semiconductors showed no field effect in the n-channel configuration. To the contrary, they could be used in p-channel FETs showing, in the saturation regime, the hole mobility approaching 10?4 cm2 V?1 s?1 – the value which slightly exceeds that measured for low molecular weight, amorphous triarylamine semiconductors. 相似文献
58.
Dr. Gabriel E. Büchel Brandon Carney Travis M. Shaffer Dr. Jun Tang Dr. Christine Austin Prof. Manish Arora Prof. Brian M. Zeglis Prof. Jan Grimm Prof. Jörg Eppinger Prof. Thomas Reiner 《ChemMedChem》2016,11(18):1978-1982
Intraoperative imaging technologies recently entered the operating room, and their implementation is revolutionizing how physicians plan, monitor, and perform surgical interventions. In this work, we present a novel surgical imaging reporter system: intraoperative chemiluminescence imaging (ICI). To this end, we have leveraged the ability of a chemiluminescent metal complex to generate near‐infrared light upon exposure to an aqueous solution of Ce4+ in the presence of reducing tissue or blood components. An optical camera spatially resolves the resulting photon flux. We describe the construction and application of a prototype imaging setup, which achieves a detection limit as low as 6.9 pmol cm?2 of the transition‐metal‐based ICI agent. As a proof of concept, we use ICI for the in vivo detection of our transition metal tracer following both systemic and subdermal injections. The very high signal‐to‐noise ratios make ICI an interesting candidate for the development of new intraoperative imaging technologies. 相似文献
59.
The voltage-dependent anion channel 1 (VDAC1) is a crucial mitochondrial transporter that controls the flow of ions and respiratory metabolites entering or exiting mitochondria. As a voltage-gated channel, VDAC1 can switch between a high-conducting “open” state and a low-conducting “closed” state emerging at high transmembrane (TM) potentials. Although cell homeostasis depends on channel gating to regulate the transport of ions and metabolites, structural hallmarks characterizing the closed states remain unknown. Here, we performed microsecond accelerated molecular dynamics to highlight a vast region of VDAC1 conformational landscape accessible at typical voltages known to promote closure. Conformers exhibiting durable subconducting properties inherent to closed states were identified. In all cases, the low conductance was due to the particular positioning of an unfolded part of the N-terminus, which obstructed the channel pore. While the N-terminal tail was found to be sensitive to voltage orientation, our models suggest that stable low-conducting states of VDAC1 predominantly take place from disordered events and do not result from the displacement of a voltage sensor or a significant change in the pore. In addition, our results were consistent with conductance jumps observed experimentally and corroborated a recent study describing entropy as a key factor for VDAC gating. 相似文献
60.