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31.
Tomoko Okuyama Jun Shirakawa Kazuki Tajima Yoko Ino Heidrun Vethe Yu Togashi Mayu Kyohara Ryota Inoue Daisuke Miyashita Jinghe Li Nozomi Goto Taiga Ichikawa Shingo Yamasaki Haruka Ohnuma Rie Takayanagi Yayoi Kimura Hisashi Hirano Yasuo Terauchi 《International journal of molecular sciences》2020,21(21)
32.
Dr. Ryota Hidese Dr. Kenichi Ataka Dr. Eckhard Bill Dr. Seigo Shima 《Chembiochem : a European journal of chemical biology》2015,16(13):1861-1865
[Fe]‐Hydrogenase (Hmd) catalyzes reversible hydride transfer from H2. It harbors an iron‐guanylylpyridinol as a cofactor with an FeII that is ligated to one thiolate, two COs, one acyl‐C, one pyridinol‐N, and solvent. Here, we report that CuI and H2O2 inactivate Hmd (half‐maximal rates at 1 μM CuI and 20 μM H2O2) and that FeII inhibits the enzyme with very high affinity (Ki=40 nM ). Infrared and EPR studies together with competitive inhibition studies with isocyanide indicated that CuI exerts its inhibitory effect most probably by binding to the active site iron‐thiolate ligand. Using the same methods, it was found that H2O2 binds to the active‐site iron at the solvent‐binding site and oxidizes FeII to FeIII. Also it was shown that FeII reversibly binds away from the active site iron, with binding being competitive to the organic hydride acceptor; this inhibition is specific for FeII and is reminiscent of that for the [FeFe]‐hydrogenase second iron, which specifically interacts with H2. 相似文献
33.
A total of fifteen saturated fatty acid esters were newly identified from the secretions of an unidentified Anaulaciulus sp. (Julida: Julidae). The fatty acid components of the esters were composed of normal chain acids (from C10 to C14) and of branched chain acids (from iso-C12 to iso-C15 and anteiso-C15). The alcohol moieties were all composed of normal chain alcohols varying from n-butanol to n-octanol. The most abundant component found in the total esters was n-hexyl laurate (64.7%). Novel compounds identified from the millipede secretion extracts include six branched iso- and anteiso-fatty
esters, an odd-numbered C11-fatty acid ester, a C13-fatty acid ester, and a C7-alcohol ester, all of which were previously undescribed natural products. In addition, a characteristic mixture of benzoquinones,
such as 2-methyl-1,4-benzoquinone, 2-methoxy-3-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, 2-methoxy-6-methyl-1,4-benzoquinone,
and 2,3-dimethoxy-5-methyl-1,4-benzoquinone were identified from the secretions, together with trace amounts of 1,4-benzoquinone. 相似文献
34.
Seiji Shinohara Jong-Gab Baek Tetsuhiko Isobe Mamoru Senna 《Journal of the American Ceramic Society》2000,83(12):3208-3210
Phase-pure perovskite Pb(Zn x Mg1– x )1/3 Nb2/3 O3 solid solution (PZ x M1– x N) is obtained for x ≦ 0.7 by heating a milled stoichiometric mixture of PbO, Mg(OH)2 , Nb2 O5 , and 2ZnCO3 ·3Zn(OH)2 ·H2 O at 1100°C for 1 h. Percent perovskite ( f P ) with respect to total crystalline phase decreases with increasing temperature of subsequent heating then increases to 900°C for the mixtures where x ≦ 0.8 and milled for 3 h. For mixtures with x = 0.9 and x = 1, f P decreases monotonically. Curie temperature increases almost linearly with increasing x up to x = 0.7. The maximum dielectric constant at 1 kHz is 2×104 and 1.7×104 for the mixture with x = 0.4 and x = 0.7, respectively. The stabilization mechanism of strained perovskite is discussed. 相似文献
35.
Yoshihiro Sugi Hiroyoshi Maekawa Yukio Hasegawa Akira Ito Ryota Asai Daisuke Yamamoto Kenichi Komura Yoshihiro Kubota Jong-Ho Kim Gon Seo 《Catalysis Today》2008,131(1-4):413-422
Catalytic properties of three-dimensional zeolites, Y (FAU), Beta (BEA), and CIT-1 (CON) zeolites were examined in the alkylation, isopropylation, sec-butylation, and tert-butylation, of biphenyl (BP), and compared to those of H-mordenite (MOR). The selectivities for 4,4′-dialkylbiphenyl (4,4′-DABP) varied with the types of zeolite and of alkylating agent. FAU, BEA, and CON gave only low selectivities for 4,4′-diisopropylbiphenyl (4,4′-DIPB) in the isopropylation, and predominant isomers were bulky and thermodynamically unstable 2,x′-DIPB (2,2′-, 2,3′-, and 2,4′-) at lower temperatures, and bulky and thermodynamically stable 3,4′- and 3,3′-DIPB at higher temperatures: this is quite different from catalytic features over MOR, which gave 4,4′-DIPB with high selectivities at moderate temperatures. These results suggest that FAU, BEA, and CON have no shape-selective nature in the isopropylation, and that the reaction is principally controlled kinetically at lower temperatures, and thermodynamically at higher temperatures. The sec-butylation gave similar results to the isopropylation. Although the selectivities for 4,4′-di-sec-butylbiphenyl (4,4′-DSBB) were higher than those in the isopropylation, predominant isomers were 2,x′-DSBB (2,2′-, 2,3′-, and 2,4′-) at lower temperatures, and 3,4′- and 3,3′-DSBB at higher temperatures. The tert-butylation gave 4,4′-di-tert-butylbiphenyl (4,4′-DTBB) in moderate to high selectivities over all zeolites at moderate temperatures: the selectivity for 4,4′-DTBB was higher than 80% over BEA and CON; however, it still remained at 50% over FAU. FAU channels with super cages are too large for selective formation of 4,4′-DTBB.
From these results, it is concluded that the selectivity for 4,4′-DABP in the alkylation over MOR, FAU, BEA, and CON is determined by the exclusion of bulky isomers at their transition states, and that the exclusion is caused by the steric restriction at the transition states of bulky isomers by the zeolite channels. 相似文献
36.
Lingyun Lyu Takeshi Hanada Naohiro Yamahira Jun Morita Ryota Yamamoto Ken Itomi Takumi Adachi Sho Kubouchi Shin Horiuchi 《应用聚合物科学杂志》2021,138(45):51443
The distribution of nano-sized silica in binary rubber blends is characterized by scanning transmission electron microscopy (STEM) tomography combined with energy dispersive X-ray spectrometry (EDX). 3D distribution of silica is visualized by STEM-EDX tomography with the tilt-series of silicon elemental maps, while the phase-separated morphologies of polyisoprene rubber (IR) and styrene-butadiene rubber (SBR) are visualized by STEM-tomography in high-angle-annular-dark field (HAADF) mode. The combination of STEM-EDX and STEM-HAADF tomography enables us to determine the distribution of silica between the two rubber phases quantitatively even with high contents of silica up to 70 phr (weight parts per hundred rubber). It is found that silica is preferentially distributed in the SBR phase, but it is also distributed in the IR phase when the IR fraction in the total rubber components is higher than 40 wt%. The preferential distribution of silica in the SBR phase improves the dispersion of the IR domains. This is the first use of this technique for a multicomponent polymer system, showing the advantage to characterize the complicated multicomponent polymer composite morphologies. 相似文献
37.
Norihiro Moriyama Yuta Kawano Qing Wang Ryota Inoue Meng Guo Makoto Yokoji Hiroki Nagasawa Masakoto Kanezashi Toshinori Tsuru 《American Institute of Chemical Engineers》2021,67(7):e17223
Pervaporation (PV) is a membrane technology that holds great promise for industrial applications. To better understand the PV mechanism, PV dehydrations of various types of organic solvents (methanol, ethanol, iso-propanol, tert-butanol, and acetone) were performed on five types of organosilica and two types of silicon carbide-based membranes, all with different pore sizes. Water permeance was dependent on the types of organic aqueous solutions, which suggested that organic solvents penetrated the pores and hindered the permeation of water. In addition, water permeance of various types of membranes in PV was well correlated with hydrogen permeance in single-gas permeation. Furthermore, a clear correlation was obtained between the permeance ratio in PV and that in single-gas permeation, which was confirmed via the modified-gas translation model. These correlations make it possible to use single-gas permeation properties to predict PV performance. 相似文献
38.
Kento Nishida Hiroshi Watanabe Ryota Murata Kai Tokumaru Rui Fujimura Shun Oshiro Taisei Nagasaki Masako Miyahisa Yuto Hiramoto Hiroto Nosaki Tadashi Imafuku Hitoshi Maeda Masafumi Fukagawa Toru Maruyama 《International journal of molecular sciences》2021,22(11)
An effective strategy is highly desirable for preventing acute kidney injury (AKI) to chronic kidney disease (CKD) transition. Thioredoxin-1 (Trx), a redox-active protein that has anti-oxidative and anti-inflammatory properties, would be a candidate for this but its short half-life limits its clinical application. In this study, we examined the renoprotective effect of long-acting Trx that is comprised of human albumin and Trx (HSA-Trx) against AKI to CKD transition. AKI to CKD mice were created by renal ischemia-reperfusion (IR). From day 1 to day 14 after renal IR, the recovery of renal function was accelerated by HSA-Trx administration. On day 14, HSA-Trx reduced renal fibrosis compared with PBS treatment. At the early phase of fibrogenesis (day 7), HSA-Trx treatment suppressed renal oxidative stress, pro-inflammatory cytokine production and macrophage infiltration, thus ameliorating tubular injury and fibrosis. In addition, HSA-Trx treatment inhibited G2/M cell cycle arrest and apoptosis in renal tubular cells. While renal Trx protein levels were decreased after renal IR, the levels were recovered by HSA-Trx treatment. Together, HSA-Trx has potential for use in the treatment of AKI to CKD transition via its effects of modulating oxidative stress and inflammation. 相似文献
39.
Masatoshi Kitakaze Ryota Chijimatsu Andrea Vecchione Toru Kitagawa Yuichiro Doki Hidetoshi Eguchi Hideshi Ishii 《International journal of molecular sciences》2021,22(14)
The recent advances in deciphering the human genome allow us to understand and evaluate the mechanisms of human genome age-associated transformations, which are largely unclear. Genome sequencing techniques assure comprehensive mapping of human genetics; however, understanding of gene functional interactions, specifically of time/age-dependent modifications, remain challenging. The age of the genome is defined by the sum of individual (inherited) and acquired genomic traits, based on internal and external factors that impact ontogenesis from the moment of egg fertilization and embryonic development. The biological part of genomic age opens a new perspective for intervention. The discovery of single cell-based mechanisms for genetic change indicates the possibility of influencing aging and associated disease burden, as well as metabolism. Cell populations with transformed genetic background were shown to serve as the origin of common diseases during extended life expectancy (superaging). Consequently, age-related cell transformation leads to cancer and cell degeneration (senescence). This article aims to describe current advances in the genomic mechanisms of senescence and its role in the spatiotemporal spread of epithelial clones and cell evolution. 相似文献
40.
Hiroyuki Kurachi Sashiro Uemura Jyunko Yotani Takeshi Nagasako Hiromu Yamada Tomotaka Ezaki Tsuyoshi Maesoba Takehiro Nakao Masaaki Ito Akira Sakurai Yahachi Saito Hisanori Shinohara 《Journal of the Society for Information Display》2005,13(9):727-733
Abstract— The synthesis of carbon‐nanotube (CNT) field emitters for FEDs by thermal chemical vapor deposition (CVD) and their structural and emission characterization are described. Multi‐walled nanotubes (MWNTs) were grown on patterned metal‐base electrodes by thermal CVD, and the grown CNTs formed a network structured layer covering the surfaces of the metal electrode uniformly, which realized uniform distribution of electron emission. A technique for growing narrow MWNTs was also developed in order to reduce the driving voltage. The diameter of MWNT depends on the growth temperature, and it has changed from 40 nm at the low temperature (675°C) to 10–15 nm at the high temperature (900–1000°C). Moreover, narrower MWNTs were grown by using the metal‐base electrode covered with a thin alumina layer and a metal catalyst layer. Double‐walled nanotubes (DWNTs) were also observed among narrow MWNTs. The emission from the narrow CNTs showed a low turn‐on electric field of 1.5 V/μm at the as‐grown layer. 相似文献