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11.
ABSTRACT The extraction of palladium (II) from chloride solutions (over a wide region of aqueous acidity) by di(2-ethylhexyl)dithiophosphates of tetraoctylammonium, tri-n-octylammonium and di-n-octylammonium in toluene at the constant chloride concentration has been studied. A synergistic effect was shown to be observed in these systems and it is explained by the formation of unusual complexes with mixed ligands. It has been established the palladium complexes, such as (R3NH)[PdCl2A], (R3NH)[PdCl2A] and (R2NH2)[PdCl2A], involving both alkylammonium cation and dialkyldithiophosphate anion are extracted under conditions of the loaded organic phase using distribution methods depending on a composition of aqueous and organic phase. At the excess of R3NHA or R2NH·HA, PdA2 is extracted into the organic phase. Table 8 reports the results obtained and indicates the domains of existence of the various species of palladium (II) extracted into the organic phase in the binary ex-tractant systems in comparison with the initial systems 相似文献
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13.
Andrey A. Buglak Alexey V. Samokhvalov Anatoly V. Zherdev Boris B. Dzantiev 《International journal of molecular sciences》2020,21(22)
Aptamers are nucleic acid analogues of antibodies with high affinity to different targets, such as cells, viruses, proteins, inorganic materials, and coenzymes. Empirical approaches allow the design of in vitro aptamers that bind particularly to a target molecule with high affinity and selectivity. Theoretical methods allow significant expansion of the possibilities of aptamer design. In this study, we review theoretical and joint theoretical-experimental studies dedicated to aptamer design and modeling. We consider aptamers with different targets, such as proteins, antibiotics, organophosphates, nucleobases, amino acids, and drugs. During nucleic acid modeling and in silico design, a full set of in silico methods can be applied, such as docking, molecular dynamics (MD), and statistical analysis. The typical modeling workflow starts with structure prediction. Then, docking of target and aptamer is performed. Next, MD simulations are performed, which allows for an evaluation of the stability of aptamer/ligand complexes and determination of the binding energies with higher accuracy. Then, aptamer/ligand interactions are analyzed, and mutations of studied aptamers made. Subsequently, the whole procedure of molecular modeling can be reiterated. Thus, the interactions between aptamers and their ligands are complex and difficult to understand using only experimental approaches. Docking and MD are irreplaceable when aptamers are studied in silico. 相似文献
14.
Zhen-Kun Huang Anatoly Rosenflanz I-Wei Chen 《Journal of the American Ceramic Society》1997,80(5):1256-1262
Using intermediate, liquid-forming compositions in the (Y,La)2 O3 -AlN system as additives, fully dense Si3 N4 ceramics with high strength at high temperature have been obtained by pressureless sintering. The ceramics contain rod-shaped β-Si3 N4 with M' or K' solid solutions as grain-boundary phases. The strength of these ceramics is 1150 MPa at 1200°C, and the room-temperature toughness is maintained at }7 MPa·m1/2 . Phase relations that are pertinent to the new additive compositions are delineated to rationalize their beneficial effects on sinterability and mechanical properties. 相似文献
15.
In this minireview we highlight a recent progress in preparation of DNA-based matrices that can be used as reactors for templating of inorganic nanomaterials and, in particular, highlight catalytic applications of such hybrid materials. We also discuss advantages and disadvantages of DNA utilization as a material and outline prospects of DNA-based technologies in future. 相似文献
16.
Zinchenko AA Tanahashi M Murata S 《Chembiochem : a European journal of chemical biology》2012,13(1):105-111
A group of azobenzene derivatives containing two quaternary ammonium groups with various intercharge distances between them was synthesised and used to control photochemically the conformation of genomic DNA by switching the distance between cationic ammonium groups in the dications. It was found that isomerisation of either dication from the trans form to cis resulted in an increase in the dication's efficiency for DNA compaction; this is associated with a decrease in intercharge distance between ammonium groups and leads to a better match of the binder's cationic groups to adjacent phosphate groups of DNA. Ammonium dications have several important advantages over the photosensitive surfactant type of diazobenzene reported earlier: they can be used at significantly lower (>100-fold) concentrations than photosensitive surfactants, and DNA conformation control can be performed over a broader concentration range of dications. The influence of intercharge distance in photosensitive dications on photo-induced DNA binding discrimination is discussed, and the molecular mechanism is proposed. 相似文献
17.
Igor V. Zagaynov Ivan V. Shelepin Anatoly A. Konovalov Ekaterina A. Obraztsova Alexander V. Naumkin Alexey V. Bykov Vladimir G. Leontiev 《Ceramics International》2021,47(6):8142-8149
Ceria based solid solutions doped by Gd, Bi, and the third dopant were synthesized by the co-precipitation method with ultrasonic treatment, followed by calcination at the temperature of 500°С. Characterization of the synthesized nanosystems by XRD, TEM, TG, Raman spectroscopy, FTIR, XPS was carried out. It is shown that all obtained powders of solid solutions crystallized into a cubic structure of the fluorite type, with an average particle size of 5–15 nm. The samples had a mesoporous structure of the pore diameter of 2–5 nm. The catalytic activity of Gd-Bi-M-Ce-O (M = Cu, Zr, Ni, Co, Mn) solid solutions was carried out. The catalyst Gd0.05Bi0.15Mn0.20Ce0.60O2 has the lowest oxidation temperature. 相似文献
18.
Anatoly A. VostrikovOxana N. Fedyaeva Dmitry Y. DubovSergey A. Psarov Mikhail Y. Sokol 《Energy》2011,36(4):1948-1955
A study of conversion of organic matter of brown coal in supercritical water (SCW) at 30 MPa, 400−760 °C and continuous supply of coal-water slurry (CWS) into a tubular reactor is presented. It was found that 48−63% (depending on the SCW temperature) of coal organic matter (COM) is ejected from CWS coal particles as liquid and gaseous products when they move through the reactor. We termed this stage of SCW conversion as dynamic conversion (DC) of coal. It turns out that the particles which underwent the DC stage did not aggregate in the reactor during static conversion (SC) within a coal layer due to continuous pumping through this layer. The experimental data on the composition of DC and SC products, degree of coal conversion, and the data on the degree of combustion of carbon in the presence of oxygen are given. 相似文献
19.
Boris F. Belokopytov Kestutis S. Laurinavichius Tatyana V. Laurinavichene Maria L. Ghirardi Michael Seibert Anatoly A. Tsygankov 《International Journal of Hydrogen Energy》2009
Eight natural microbial consortia collected from different sites were tested for dark, hydrogen production during starch degradation. The most active consortium was from silo pit liquid under mesophilic (37 °C) conditions. The fermentation medium for this consortium was optimized (Fe, NH4+, phosphates, peptone, and starch content) for both dark fermentation and for subsequent purple photosynthetic bacterial H2 photoproduction [Laurinavichene TV, Tekucheva DN, Laurinavichius KS, Ghirardi ML, Seibert M, Tsygankov AA. Towards the integration of dark and photo fermentative waste treatment. 1. Hydrogen photoproduction by purple bacterium Rhodobacter capsulatus using potential products of starch fermentation. Int J Hydrogen Energy 2008;33(23):7020–26], in the presence of the spent dark, fermentation effluent. The addition of Zn (10 mg L−1), as a methanogenesis inhibitor that does not inhibit purple bacteria at this concentration, also did not inhibit dark, fermentative H2 production. The influence of various fermentation end products at different concentrations (up to 30 g L−1) on dark, H2 production was also examined. Added lactate stimulated, but added isobutyrate and butanol strongly inhibited gas production. Under optimal conditions the fermentation of starch (30 g L−1) resulted in 5.7 L H2 L−1 of culture (1.6 mol H2 per mole of hexose) with the co-production mainly of butyrate and acetate. 相似文献
20.