全文获取类型
收费全文 | 933篇 |
免费 | 51篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 50篇 |
化学工业 | 286篇 |
金属工艺 | 20篇 |
机械仪表 | 15篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 59篇 |
轻工业 | 89篇 |
水利工程 | 5篇 |
石油天然气 | 3篇 |
无线电 | 40篇 |
一般工业技术 | 155篇 |
冶金工业 | 104篇 |
原子能技术 | 24篇 |
自动化技术 | 124篇 |
出版年
2023年 | 23篇 |
2022年 | 16篇 |
2021年 | 38篇 |
2020年 | 15篇 |
2019年 | 18篇 |
2018年 | 36篇 |
2017年 | 32篇 |
2016年 | 44篇 |
2015年 | 17篇 |
2014年 | 43篇 |
2013年 | 59篇 |
2012年 | 47篇 |
2011年 | 47篇 |
2010年 | 41篇 |
2009年 | 57篇 |
2008年 | 38篇 |
2007年 | 36篇 |
2006年 | 30篇 |
2005年 | 28篇 |
2004年 | 13篇 |
2003年 | 31篇 |
2002年 | 17篇 |
2001年 | 18篇 |
2000年 | 20篇 |
1999年 | 22篇 |
1998年 | 54篇 |
1997年 | 20篇 |
1996年 | 19篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有985条查询结果,搜索用时 15 毫秒
1.
Hiromi Eba Yuki Masuzoe Toru Sugihara Hayao Yagi Tian Liu 《International Journal of Hydrogen Energy》2021,46(18):10642-10652
Ammonia generation was studied in the reaction between water and nitrogen-containing iron at 323 K and atmospheric pressure. Similar to metallic Fe, the interstitial compound Fe3N reduced water through Fe oxidation to produce hydrogen gas, while the N combined with atomic hydrogen to produce ammonia as a byproduct. The addition of carbon dioxide to this system accelerated the reaction with concomitant consumption of carbon dioxide. The promoted ammonia production upon addition of carbon dioxide can be attributed to the generation of atomic hydrogen from the redox reaction of carbonic acid and Fe, as well as removal of used Fe from the reaction system through the formation of a soluble carbonato complex. When carbonate was added to the reaction system, the production rates of ammonia and hydrogen increased further. The results here confirmed that ammonia can be synthesized from iron nitride under mild conditions by utilizing carbon dioxide. 相似文献
2.
Ryo Hashikawa Yasuhiro Fujii Atsushi Kinomura Takeshi Saito Arifumi Okada Takashi Wakasugi Kohei Kadono 《Journal of the American Ceramic Society》2019,102(4):1642-1651
Radiophotoluminescence phenomena have been widely investigated on various types of materials for dosimetry applications. We report that an aluminoborosilicate glass containing 0.005 mol% copper exhibits intense photoluminescence in the visible region induced by X-ray and γ-ray irradiation. The luminescence is assigned to the 3d94s1 → 3d10 transition of Cu+. The proportionality of the intensity of the induced photoluminescence to the irradiation dose was confirmed up to 0.5 kGy using 60Co γ-ray irradiation. Based on the spectroscopic results, a potential mechanism was proposed for the enhancement of the photoluminescence. The exposure to the ionizing radiation generates electron-hole pairs in the glass, and the electrons are subsequently captured by the Cu2+ ions, which are converted to Cu+ and emit the luminescence. For the glass containing 0.01 mol% copper, the pronounced enhancement of the photoluminescence was not observed because the reverse reaction, ie, the capture of the holes by the Cu+ ions, becomes prominent. The photoluminescence induced by the irradiation was stably observed for the glasses kept at room temperature and even for the glasses heat-treated at 150°C. However, the induced photoluminescence could be eliminated by the heat treatment at a temperature at 500°C, and the glass returned to the initial pre-irradiation state. The Cu-doped aluminoborosilicate glass is a potential candidate for use in dosimetry applications. 相似文献
3.
Isothermal nucleic-acid amplification methods such as Loop-Mediated isothermal AMPlification (LAMP) are increasingly appealing alternatives to PCR for use in portable diagnostic system due to the low cost, weight, and power requirements of the instrumentation. As such, interest in developing new probes and other functionality based on the LAMP reaction has been intense. Here, we report on the development of duplexed LAMP assays for pathogen detection using spectrally unique Assimilating Probes. As proof of principle, we used a reaction for Salmonella enterica as a model coupled with a reaction for λ-phage DNA as an internal control, as well as a duplexed assay to sub-type specific quarantine strains of the bacterial wilt pathogen Ralstonia solanacearum. Detection limits for bacterial DNA analyzed in individual reactions was less than 100 genomic equivalents in all cases, and increased by one to two orders of magnitude when reactions were coupled in duplexed formats. Even so, due to the more robust activity of newly available strand-displacing polymerases, the duplexed assays reported here were more powerful than analogous individual reactions reported only a few years ago, and represent a significant advance for incorporation of internal controls to validate assay results in the field. 相似文献
4.
5.
Donguk Kim Author Vitae Author Vitae Kokichi Sugihara Author Vitae 《Computer aided design》2006,38(1):14-21
The Apollonius Tenth Problem, as defined by Apollonius of Perga circa 200 B.C., has been useful for various applications in addition to its theoretical interest. Even though particular cases have been handled previously, a general framework for the problem has never been reported. Presented in this paper is a theory to handle the Apollonius Tenth Problem by characterizing the spatial relationship among given circles and the desired Apollonius circles. Hence, the given three circles in this paper do not make any assumption regarding on the sizes of circles and the intersection/inclusion relationship among them. The observations made provide an easy-to-code algorithm to compute any desired Apollonius circle which is computationally efficient and robust. 相似文献
6.
Satoshi Takeuchi Ryo Sugihara 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1998,410(3):104-508
The longitudinal electric field of single and double Gaussian laser beams are used to accelerate electrons. The longitudinal field of the single beam is concentrated on the axis and is favourable for acceleration. A set of two beams is considered. Beams run parallel, collinearly, overlap partially and have a phase difference iπ in between. As a result, the transverse components of fields cancel each other while the longitudinal components are double-fold. In both schemes, the electrons are accelerated in lengths of the Rayleigh range, which is common to the plasma-based accelerators. 相似文献
7.
K Yamada K Senzaki Y Komori T Nikai H Sugihara T Nabeshima 《Canadian Metallurgical Quarterly》1997,762(1-2):72-78
The role of glial cells in nitric oxide production in the cerebellum of conscious rats was investigated with a glial selective metabolic inhibitor, fluorocitrate. The levels of nitric oxide metabolites (nitrite plus nitrate) in the dialysate following in vivo microdialysis progressively increased to more than 2-fold the basal levels during a 2-h infusion of fluorocitrate (1 mM), and the increase persisted for more than 2 h after the treatment. Pretreatment with N(G)-nitro-L-arginine methyl ester attenuated the fluorocitrate-induced increase in nitric oxide metabolite levels. None of the glutamate receptor antagonists, including D(-)-2-amino-5-phosphonopentanoic acid, 6,7-dinitroquinoxaline-2,3-dione, and (+/-)-alpha-methyl-4-carboxyphenylglycine, inhibited the fluorocitrate-induced increase. The L-arginine-induced increase was significantly reduced by fluorocitrate treatment, while N-methyl-D-aspartate, (+)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid, and trans-(+/-)-1-amino-(1S,3R)-cyclopentane-dicarboxylic acid increased nitric oxide metabolites levels in the fluorocitrate-treated rats, as much as in control animals. These results suggest that glial cells play an important role in modulating nitric oxide production in the cerebellum by regulating L-arginine availability. 相似文献
8.
Present-day power systems operate with high reliability, and it is rare that a blackout will extend over an entire system swiftly and securely. This paper considers automatic power supply to loads after a complete blackout of a system. First, taking into account characteristics of generators, loads, and initial power sources, a method is proposed of allocating several generators to each load in parallel to the system and supplying power to the load sequentially. Second, to remove the imbalance between supply and demand of power, a method is proposed of adjusting the amount of supply and generation according to a present imbalance and the sum of past ones. Third, to automatically issue orders for start-up, parallel, follow-up, stand-by, and stoppage of generators, several rules for each power station are set and an expert system is made based on them. Finally, the expert system is applied to a model power system, and it is verified that it can restore loads without any trouble for a complete blackout which occur at any time of a day and in any restoration pattern. 相似文献
9.
Dr. Daisuke Fujiwara Kousuke Mihara Ryo Takayama Yusuke Nakamura Prof. Mitsuhiro Ueda Prof. Takeshi Tsumuraya Prof. Ikuo Fujii 《Chembiochem : a European journal of chemical biology》2021,22(24):3406-3409
Conformationally constrained peptides hold promise as molecular tools in chemical biology and as a new modality in drug discovery. The construction and screening of a target-focused library could be a promising approach for the generation of de novo ligands or inhibitors against target proteins. Here, we have prepared a protein kinase-focused library by chemically modifying helix-loop-helix (HLH) peptides displayed on phage and subsequently tethered to adenosine. The library was screened against aurora kinase A (AurA). The selected HLH peptide Bip - 3 retained the α-helical structure and bound to AurA with a KD value of 13.7 μM. Bip - 3 and the adenosine-tethered peptide Bip - 3 - Adc provided IC50 values of 103 μM and 7.7 μM, respectively, suggesting that Bip - 3 - Adc bivalently inhibited AurA. In addition, the selectivity of Bip - 3 - Adc to several protein kinases was tested, and was highest against AurA. These results demonstrate that chemical modification can enable the construction of a kinase-focused library of phage-displayed HLH peptides. 相似文献
10.
The permeation and separation characteristics of aqueous polymer solutions using acrylonitrile-styrene copolymer membranes were investigated under various conditions. The membranes obtained from dimethyl sulfoxide solution of acrylonitrile-styrene copolymer have not a sufficient reproducibility and stability of permeation. These lacks were improved by adding ethylene glycol or glycerol to the casting solution and treating the membranes with pressure. The permeation and separation characteristics were influenced significantly by the additional amount of above additives, the heat treatment temperature, and the operating pressure. It was found that the concentration polarization of poly(vinyl alcohol) molecules onto the surface of the acrylonitrile-styrene copolymer membranes is smaller than that onto hydrophilic polymer membranes such as membranes of cellulose acetate, cellulose nitrate, and nylon 12, etc. Moreover, the acrylonitrile-styrene copolymer membranes show better performance for separation and concentrating of aqueous polymer solutions than hydrophilic membranes. 相似文献