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101.
102.
103.
Impact of coagulation and adsorption on DOC fractions of secondary effluent and resulting fouling behaviour in ultrafiltration 总被引:2,自引:0,他引:2
Membrane fouling by macromolecular dissolved organic compounds is still a fundamental drawback in low-pressure membrane filtration of secondary effluent. In this study, pre-treatment of secondary effluent by coagulation and/or adsorption was investigated in terms of removal of different dissolved organic carbon (DOC) fractions, especially macromolecular substances. DOC fractionation has been characterised by size exclusion chromatography. Adsorption tests using four commercially available activated carbons yielded a removal of small as well as larger organic compounds, revealing differences in the affinity towards macromolecules depending on the type of applied activated carbon. By contrast, coagulation removed predominantly larger molecules, i.e., biopolymers and humic substances. In terms of DOC reduction, the coagulant ferric chloride was superior to aluminium chloride. A combination of coagulation and adsorption resulted in the addition of individual removal efficiencies, suggesting that different fractions of organic compounds were involved in each of the processes. After removal of macromolecular organic compounds either by coagulation or by adsorption, a significant reduction of membrane fouling was observed in tests using two different types of ultrafiltration flat-sheet membranes in 20-h cross-flow filtration tests. 相似文献
104.
Dr. Umberto Maria Battisti Dr. Chunxia Gao Oscar Nilsson Dr. Fady Akladios Dr. Aleksei Lulla Dr. Agnieszka Bogucka Dr. Amalyn Nain-Perez Dr. Liliana Håversen Dr. Woonghee Kim Prof. Jan Boren Prof. Marko Hyvönen Prof. Mathias Uhlen Prof. Adil Mardinoglu Prof. Morten Grøtli 《Chembiochem : a European journal of chemical biology》2023,24(1):e202200339
Enzymes are effective biological catalysts that accelerate almost all metabolic reactions in living organisms. Synthetic modulators of enzymes are useful tools for the study of enzymatic reactions and can provide starting points for the design of new drugs. Here, we report on the discovery of a class of biologically active compounds that covalently modifies lysine residues in human liver pyruvate kinase (PKL), leading to allosteric activation of the enzyme (EC50=0.29 μM). Surprisingly, the allosteric activation control point resides on the lysine residue K282 present in the catalytic site of PKL. These findings were confirmed by structural data, MS/MS experiments, and molecular modelling studies. Altogether, our study provides a molecular basis for the activation mechanism and establishes a framework for further development of human liver pyruvate kinase covalent activators. 相似文献
105.
Mathias Deckers Ernst Wilhelm Pfitzinger Wilfried Ulm 《热力透平》2004,33(4):209-215
This paper presents Siemens' latest improvements in steam turbine blading and blading design tools. The technology offers improved performance and highest efficiencies for a wide range of steam turbine applications. 相似文献
106.
Mathias Herrmann Jan RäthelSören Höhn Jens EichlerAlexander Michaelis 《Journal of the European Ceramic Society》2011,31(13):2401-2406
Hexagonal boron nitride/titanium diboride composites are widely used as evaporation boats for aluminium deposition to produce functional and decorative layers on different target materials. The lifetime of such a material is limited mainly by the interaction of the metal with the ceramic substrate, but the corrosion mechanism has still not yet been thoroughly investigated and understood. In this article the corrosion mechanism for the evaporation boats used was investigated using thermodynamic calculations, FESEM, EDX and XRD phase analysis. The analysis showed that hexagonal boron nitride (hBN), which is thermodynamically less stable than TiB2, is passivated during the application process through the formation of AlN surface layers, whereas the thermodynamically more stable TiB2 phase dissolves and Ti-rich components precipitate in cooler regions of the evaporation boats. 相似文献
107.
To setup efficient wireless mesh networks, it is fundamental to limit the overhead needed to localize a mobile user. A promising
approach is to rely on a rendezvous-based location system where the current location of a mobile node is stored at specific
nodes called locators. Nevertheless, such a solution has a drawback, which happens when the locator is far from the source–destination
shortest path. This results in a triangular location problem and consequently in increased overhead of signaling messages.
One solution to prevent this problem would be to place the locator as close as possible to the mobile node. This requires
however to predict the mobile node’s location at all times. To obtain such information, we define a mobility prediction model
(an agenda) that, for each node, specifies the mesh router that is likely to be the closest to the mobile node at specific
time periods. The location service that we propose formalizes the integration of the agenda with the management of location
servers in a coherent and self-organized fashion. To evaluate the performance of our system compared to traditional approaches,
we use two real-life mobility datasets of Wi-Fi devices in the Dartmouth campus and Taxicabs in the bay area of San Francisco.
We show that our strategy significantly outperforms traditional solutions; we obtain gains ranging from 39 to 72% compared
to the centralized scheme and more than 35% compared to a traditional rendezvous-based solution. 相似文献
108.
Mathias Herrmann Sören Höhn Axel Bales 《Journal of the European Ceramic Society》2012,32(7):1313-1319
The reproducible sintering and microstructure formation of α- and α/β-Sialons is a precondition for the production of such materials with reproducible properties.The Rietveld method was used for quantitative analysis of the phase composition and the kinetics of incorporation of the rare earth into the α-Sialon structure. The analysis showed that in the early stages of sintering more rare earth cations were incorporated into the grains than would be expected from the equilibrium conditions. This was observed for all investigated rare earths (Y, Nd and Yb) with different ionic radii. The consequences for sintering and microstructure formation are the fast disappearing of the transient liquid and the formation of polytypes. The use of excess of rare earth in comparison to the stoichiometric Sialon composition results in a stable residual liquid. It allows reproducible densification, anisotropic grain growth and materials with high fracture toughness. 相似文献
109.
110.
Several carbon‐black filled styrene‐butadiene rubbers are subjected to monotonic uniaxial tension tests in order to investigate the effects of the amount of fillers and of the crosslink density on their mechanical properties. The Young modulus, the volume changes associated with material damage and the stretch to failure are extracted and discussed. Results compare well to the literature results when exist and quantitative analysis are proposed when possible. Results show that filled rubbers are not incompressible when submitted to uniaxial tension tests and their volume changes are strongly dependent of the amount of fillers but are unaffected by the crosslink density. The latter shows strong impact on the filled rubbers stretch to failure but more interestingly this impact is comparable to what is encountered in unfilled rubbers. The stretch to failure is improved by the addition of fillers with an optimum for material filled around 30 phr. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献