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171.
Low-pressure liquid chromatography, high-performance liquid chromatography, and field ionization mass spectrometry (f.i.m.s.) were used to obtain compositional information on large-ring number polycyclic aromatic hydrocarbon (PAH) present in a non-distillable coal liquid sample. A highly selective h.p.l.c. method for the separation of (PAH) from polar compounds was applied to nitrogen-compound fractions derived from a Wyodak non-distillable ( > 427 °C) coal-liquid sample. F.i.m.s. analyses revealed that the PAH subfractions isolated by the h.p.l.c. procedure contained large-ring number PAH and relatively few nitrogen compounds. The methods developed can generally be applied to the analyses of complex organic mixtures, and in conjunction with other methods, can yield detailed polycyclic aromatic hydrocarbon compositional information. 相似文献
172.
Garrett BC Dixon DA Camaioni DM Chipman DM Johnson MA Jonah CD Kimmel GA Miller JH Rescigno TN Rossky PJ Xantheas SS Colson SD Laufer AH Ray D Barbara PF Bartels DM Becker KH Bowen KH Bradforth SE Carmichael I Coe JV Corrales LR Cowin JP Dupuis M Eisenthal KB Franz JA Gutowski MS Jordan KD Kay BD Laverne JA Lymar SV Madey TE McCurdy CW Meisel D Mukamel S Nilsson AR Orlando TM Petrik NG Pimblott SM Rustad JR Schenter GK Singer SJ Tokmakoff A Wang LS Wettig C Zwier TS 《Chemical reviews》2005,105(1):355-390
173.
Five phenolic compounds produced by decomposing rice straw and sterile extracts of decomposing rice straw in soil were very inhibitory to growth of three strains ofRhizobium. The effects were additive and in several instances synergistic. The phenolic compounds also reduced nodule numbers and hemoglobin content of the nodules in two bean (Phaseolus vulgaris) varieties. Extracts of decomposing rice straw in soil (same concentration as in the soil) significantly reduced N2 fixation (acetylene reduction) in Bush Black Seeded beans. This may explain in part the great reduction in soybean yields in Taiwan following rice crops when the rice stubble is left in the field. 相似文献
174.
Responses of fig wasps to host plant volatile cues 总被引:4,自引:0,他引:4
Fig wasps (Chalcidoidea; Agaonidae) are intimately associated with the 750 or so species of fig trees (Ficus, Moraceae). Each tree species is usually pollinated by a single species of wasp belonging to the subfamily Agaoninae, while other wasps of the family are parasitoids or seed predators. Previous experiments have shown that the wasps are attracted to the trees by volatiles emanating from the figs. Using fig-bearing trees and arrays of sticky traps baited with figs, we investigated the specificity of wasp attraction and its timing. The pollinators of two closely relatedFicus species were specifically attracted to figs of their host species and only at the time when figs were ready to be pollinated. Some nonpollinating fig wasps appear to respond to the same volatile cues. 相似文献
175.
Masao Tomikawa Frank W. Harris Stephen Z. D. Cheng Edward Galentier 《Reactive and Functional Polymers》1996,30(1-3):101-107
A series of new, substituted pyromellitic dianhydrides were synthesized from 1,2,4,5-tetramethylbenzene. New soluble rigid-rod polyimides were obtained from the dianhydrides and 2,2′-bis(trifluoromethyl)-4,4′-biphenyl (PFMB) in phenolic solvents in the presence of isoquinoline as a catalyst. The polyimides are soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), m-cresol and other solvents, in spite of having no bending in their rigid structures.
UV irradiation changed color of the polyimide solutions and also their viscosity. We observed new absorbance in the 700-nm region and an ESR signal by UV irradiation. The new visible absorbance and the ESR signal are derived from the same origin. They are attributed to the anion radical of the diimide moiety in the polyimide as deduced from the hyper fine structure of the ESR signal. In addition, UV irradiation diminishes the solution viscosity. 相似文献
176.
Magat Julie Ozenne Valéry Cedilnik Nicolas Naulin Jérôme Haliot Kylian Sermesant Maxime Gilbert Stephen H. Trew Mark Haissaguerre Michel Quesson Bruno Bernus Olivier 《Magma (New York, N.Y.)》2021,34(5):741-755
Magnetic Resonance Materials in Physics, Biology and Medicine - The aim of the study is to compare structure tensor imaging (STI) with diffusion tensor imaging (DTI) of the sheep heart... 相似文献
177.
This paper describes research undertaken by the authors to develop an integrated measurement and modeling methodology for water quality management of estuaries. The approach developed utilizes modeling and measurement results in a synergistic manner. Modeling results were initially used to inform the field campaign of appropriate sampling locations and times, and field data were used to develop accurate models.Remote sensing techniques were used to capture data for both model development and model validation. Field surveys were undertaken to provide model initial conditions through data assimilation and determine nutrient fluxes into the model domain. From field data, salinity relationships were developed with various water quality parameters, and relationships between chlorophyll a concentrations, transparency, and light attenuation were also developed. These relationships proved to be invaluable in model development, particularly in modeling the growth and decay of chlorophyll a. Cork Harbour, an estuary that regularly experiences summer algal blooms due to anthropogenic sources of nutrients,was used as a case study to develop the methodology. The integration of remote sensing, conventional fieldwork, and modeling is one of the novel aspects of this research and the approach developed has widespread applicability. 相似文献
178.
Mount Emily Gaultney Daniel Vrijsen Geert Adams Michael Baek So-Young Hudek Kai Isabella Louis Crain Stephen van Rynbach Andre Maunz Peter Kim Jungsang 《Quantum Information Processing》2016,15(12):5281-5298
Quantum Information Processing - Many of the challenges of scaling quantum computer hardware lie at the interface between the qubits and the classical control signals used to manipulate them.... 相似文献
179.
In this paper, we introduce new methods for finding functions that lower bound the value function of a stochastic control problem, using an iterated form of the Bellman inequality. Our method is based on solving linear or semidefinite programs, and produces both a bound on the optimal objective, as well as a suboptimal policy that appears to works very well. These results extend and improve bounds obtained in a previous paper using a single Bellman inequality condition. We describe the methods in a general setting and show how they can be applied in specific cases including the finite state case, constrained linear quadratic control, switched affine control, and multi‐period portfolio investment. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
180.
Stephen Abell Nhan Do 《International Journal of Parallel, Emergent and Distributed Systems》2016,31(5):450-468
This article presents a GPU-based single-unit deadlock detection methodology and its algorithm, GPU-OSDDA. Our GPU-based design utilizes parallel hardware of GPU to perform computations and thus is able to overcome the major limitation of prior hardware-based approaches by having the capability of handling thousands of processes and resources, whilst achieving real-world run-times. By utilizing a bit-vector technique for storing algorithm matrices and designing novel, efficient algorithmic methods, we not only reduce memory usage dramatically but also achieve two orders of magnitude speedup over CPU equivalents. Additionally, GPU-OSDDA acts as an interactive service to the CPU, because all of the aforementioned computations and matrix management techniques take place on the GPU, requiring minimal interaction with the CPU. GPU-OSDDA is implemented on three GPU cards: Tesla C2050, Tesla K20c, and Titan X. Our design shows overall speedups of 6-595X over CPU equivalents. 相似文献