全文获取类型
收费全文 | 616篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 21篇 |
综合类 | 1篇 |
化学工业 | 184篇 |
金属工艺 | 16篇 |
机械仪表 | 3篇 |
建筑科学 | 9篇 |
能源动力 | 10篇 |
轻工业 | 19篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 97篇 |
一般工业技术 | 188篇 |
冶金工业 | 19篇 |
原子能技术 | 8篇 |
自动化技术 | 73篇 |
出版年
2024年 | 2篇 |
2023年 | 26篇 |
2022年 | 41篇 |
2021年 | 41篇 |
2020年 | 34篇 |
2019年 | 19篇 |
2018年 | 32篇 |
2017年 | 12篇 |
2016年 | 14篇 |
2015年 | 22篇 |
2014年 | 19篇 |
2013年 | 29篇 |
2012年 | 42篇 |
2011年 | 42篇 |
2010年 | 35篇 |
2009年 | 30篇 |
2008年 | 23篇 |
2007年 | 37篇 |
2006年 | 31篇 |
2005年 | 17篇 |
2004年 | 20篇 |
2003年 | 11篇 |
2002年 | 14篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1994年 | 4篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1962年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有650条查询结果,搜索用时 15 毫秒
51.
Jessica Schulz Thomas Siegert Enrico Reimer Christian Labadie Julian Maclaren Michael Herbst Maxim Zaitsev Robert Turner 《Magma (New York, N.Y.)》2012,25(6):443-453
Object
Prospective motion correction using data from optical tracking systems has been previously shown to reduce motion artifacts in MR imaging of the head. We evaluate a novel optical embedded tracking system.Materials and methods
The home-built optical embedded tracking system performs image processing within a 7T scanner bore, enabling high speed tracking. Corrected and uncorrected in vivo MR volumes are acquired interleaved using a modified 3D FLASH sequence, and their image quality is assessed and compared.Results
The latency between motion and correction of the slice position was measured to be (19?±?5)?ms, and the tracking noise has a standard deviation no greater than 10???m/0.005° during conventional MR scanning. Prospective motion correction improved the edge strength by 16?% on average, even though the volunteers were asked to remain motionless during the acquisitions.Conclusion
Using a novel method for validating the effectiveness of in vivo prospective motion correction, we have demonstrated that prospective motion correction using motion data from the embedded tracking system considerably improved image quality. 相似文献52.
53.
Sergey Nickolayevich Mensov Gleb A. Abakumov Maxim V. Arsenyev Maxim A. Baten'kin Sergey A. Chesnokov Alexey N. Konev Yuri V. Polushtaytsev Margarita P. Shurygina Maria Yu. Zakharina 《应用聚合物科学杂志》2020,137(34):48976
The process of two-wave photopolymerization of a UV-curable composition with an optically degrading inhibitor is considered. By numerical simulation, it is shown that in the composition layer uniformly exposed to UV-radiation, such systems allow getting segments with different conversion under the action of inhomogeneous visible light. Based on the data on the photopolymerization kinetics of the compositions from triethylene glycol dimethacrylate (TEGDMA) and bisphenol-A glycidyl dimethacrylate (bis-GMA) with the UV-initiator 2,2-dimethoxy-2-phenylacetophenone (DMPA), it was shown that 3,5-di-tert-butyl-o-benzoquinone (35Q) with N,N-dimethylaniline (DMA, “Aldrich”, 99%) can serve as an inhibitor that degrades under action of visible radiation. Combining inhomogeneous visible light generated with a conventional DLP-projector and uniform UV-radiation of LED (365 nm) the two-wave lithographic process was implemented to create polymeric 2D-structures in 20 μm layer of the compositions from TEGDMA (70)/bis-GMA (30)/DMPA (0.05 wt%)/35Q (0.5 wt%)/DMA (1 wt%). 相似文献
54.
Roman S. Kovylin Maxim A. Baten’kin Tatyana I. Kulikova Catherine G. Ermolaeva Olga G. Zamyshlyayeva Sergei A. Chesnokov 《Journal of Polymer Research》2018,25(9):208
A new approach to the preparation of hydrophobic porous polymers has been proposed. Three series of porous polymers which pores equally well-absorbed as water and organic liquids (benzene and iso-octane) were synthesized by visible light polymerization from compositions based on three different dimethacrylic esters with n-butanol. Three block copolymers based on N-vinylpyrrolidone and 2,2,3,3-tetrafluoropropyl methacrylate, differing in the length of the poly-(2,2,3,3-tetrafluoropropyl methacrylate) block, were synthesized for the purpose of hydrophobization of such porous polymers. A distinctive feature of synthesized block copolymers is that they are soluble only in methanol. It has been found that the treatment of porous polymers only with 2 wt.% of block copolymer methanol solution leads to a decrease water uptake by an order of magnitude, and the absorption of organic liquids does not change. In the course of the study it was possible to obtain a hydrophobic porous polymer sample that has water contact angle θ?=?121° and a low value of the polar component of the surface Gibbs energy (\( {\gamma}_s^p=0.2 \) mJ·m?2). The fundamental possibility of using such material for purification of organic liquids from water is shown. 相似文献
55.
Pavel B. Dzhevakov Maxim A. Topchiy Daria A. Zharkova Oleg S. Morozov Andrey F. Asachenko Mikhail S. Nechaev 《Advanced Synthesis \u0026amp; Catalysis》2016,358(6):977-983
Solvent‐free protocols for Miyaura borylation and the one‐pot, two‐step homocoupling of aryl halides are reported for the first time. Bis(dibenzylideneacetone)palladium(0) [Pd(dba)2] is an optimal source of palladium for Miyaura borylation, while for one‐pot two‐step homocoupling palladium(II) acetate [Pd(OAc)2] gives highest yields. Aryl bromides are coupled most efficiently using the DPEphos ligand. Chlorides are coupled using XPhos. The developed protocols are robust, versatile and easily reproducible on a large scale.
56.
Synthesis and gas permeation parameters of metathesis polytricyclononenes with pendant Me3E‐groups (E = C,Si, Ge) 下载免费PDF全文
Maxim Bermeshev Boris Bulgakov Lyudmila Starannikova Georgii Dibrov Pavel Chapala Dmitry Demchuk Yurii Yampolskii Eugene Finkelshtein 《应用聚合物科学杂志》2015,132(5)
Metathesis polytricyclononenes were synthesized via ROMP polymerization in the presence of the 1‐st generation Grubbs catalyst and their gas‐transport properties were studied for the first time. The aim of this work was to evaluate the influence of Me3E‐groups (E = C, Si, Ge) on gas permeation parameters of ROMP materials. New metathesis poly(3‐tert‐butyltricyclononene‐7) and poly(3‐trimethylgermyltricyclononene‐7) were obtained with high yields (up to 95%) and high‐molecular weights (Mw~3–7×105 g mol?1). The glass transition temperatures of the ROMP polytricyclononenes with Me3E‐groups decreased when E was changed from C to Si and then to Ge. It was shown that the polytricyclononene containing Me3Si‐groups has the highest gas permeability while the polytricyclononene containing Me3C‐substituents has the lowest gas permeability. In addition, the gas permeation parameters were estimated for ROMP Me3Si‐ and Me3Ge‐substituted polytricyclonona‐3,7‐dienes. So the influence of the second double bond in the monomer units on the permeability of the polymers obtained was studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41395. 相似文献
57.
Maxim Stolyarchuk Julie Ledoux Elodie Maignant Alain Trouv Luba Tchertanov 《International journal of molecular sciences》2021,22(2)
Redox (reduction–oxidation) reactions control many important biological processes in all organisms, both prokaryotes and eukaryotes. This reaction is usually accomplished by canonical disulphide-based pathways involving a donor enzyme that reduces the oxidised cysteine residues of a target protein, resulting in the cleavage of its disulphide bonds. Focusing on human vitamin K epoxide reductase (hVKORC1) as a target and on four redoxins (protein disulphide isomerase (PDI), endoplasmic reticulum oxidoreductase (ERp18), thioredoxin-related transmembrane protein 1 (Tmx1) and thioredoxin-related transmembrane protein 4 (Tmx4)) as the most probable reducers of VKORC1, a comparative in-silico analysis that concentrates on the similarity and divergence of redoxins in their sequence, secondary and tertiary structure, dynamics, intraprotein interactions and composition of the surface exposed to the target is provided. Similarly, hVKORC1 is analysed in its native state, where two pairs of cysteine residues are covalently linked, forming two disulphide bridges, as a target for Trx-fold proteins. Such analysis is used to derive the putative recognition/binding sites on each isolated protein, and PDI is suggested as the most probable hVKORC1 partner. By probing the alternative orientation of PDI with respect to hVKORC1, the functionally related noncovalent complex formed by hVKORC1 and PDI was found, which is proposed to be a first precursor to probe thiol–disulphide exchange reactions between PDI and hVKORC1. 相似文献
58.
Maxim Lebedev Jun Akedo Atsushi Iwata Satoshi Sugimoto Kouichiro Inomata 《Journal of the American Ceramic Society》2004,87(9):1621-1624
This paper describes the magnetic properties of NiZnCu ferrite film deposited at room temperature by an aerosol deposition method (ADM). The thickness of the film was 6 μm and the deposition rate was estimated as 2 μm/min. The microstructure of as-deposited at room temperature films consists of randomly oriented nanocrystallites with a size of 20 nm. As-deposited and annealed films exhibited the following magnetic properties: intensity of magnetization M s = 0.147 T (117 emu/cm3 ), coercivity H c = 40.58 kA/m (510 Oe); and M s = 0.3 T (250 emu/cm3 ), H c = 14.95 kA/m (188 Oe), respectively. 相似文献
59.
Sublattice-Spin Coherent Contribution to the Conductivity of Graphene Within Quasiclassical Approach
The charge carriers in graphene are characterised by an additional quantum degree of freedom—sublattice index—which, in turn, is entangled with the quasiparticle momentum. We propose a quasiclassical model which describes kinetics of such particles. Solving accordingly modified Boltzmann kinetic equation we found a way how to distinguish between samples with the domination of short and long range scatterers from the conductivity measurements. The model proposed explains recent transport experiments with chemically doped as well as suspended graphene. 相似文献
60.
An improved PSF mapping method for EPI distortion correction in human brain at ultra high field (7T)