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排序方式: 共有695条查询结果,搜索用时 15 毫秒
51.
Zbigniew Czech 《应用聚合物科学杂志》2003,87(8):1354-1357
This article shows the influence of some chain‐transfer agents as inhibitors for acrylic solvent‐based polymerization. These chain‐transfer agents can offer significant advantages, as outlined below. The following chain‐transfer agents were studied to stop or slow down the polymerization process in the case of a runaway: n‐dodecyl mercaptan, trimethylolpropane‐trimercaptoacetate, phenothiazine, diphenylphenylen diamine, cuprum oxide, isopropanol, toluene, and carbon tetrachloride. Synthesized pressure‐sensitive adhesive based on acrylic polymers and containing 2‐ethylhexyl acrylate, methyl acrylate, and acrylic acid were used for the production of self‐adhesives with high cohesion. The polymerization was accomplished in ethyl acetate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1354–1357, 2003 相似文献
52.
Honglin Chen Hong Yang Yevgenia Briker Craig Fairbridge Oladipo Omotoso Lianhui Ding Ying Zheng Zbigniew Ring 《Catalysis Today》2007,125(3-4):256-262
Pt supported on a carbon molecular sieve (Pt/CMS) was prepared by pyrolysis of polyfurfuryl alcohol containing pre-reduced Pt particles. The catalysts were characterized by hydrogen chemisorption, XRD, N2 adsorption/desorption and TEM. Hydrogen chemisorption showed that not all the Pt particles were exposed to H2 molecules. Oxidation treatment made Pt particles more accessible to H2. Catalyst activity was evaluated by hydrogenation of 1-hexene. Hydrogen spillover was demonstrated by diluting Pt/CMS with activated carbon or hydrogen type zeolite Y. The initial conversion of 1-hexene was increased from 86.5% to 98.5% and to 100% when Pt/CMS was diluted with activated carbon and hydrogen type zeolite, respectively. The high initial conversion was sustained for 6 h in the presence of diluents while the conversion decreased quickly for Pt/CMS alone. 相似文献
53.
An ion beam milling system utilizing a Kaufman-type source to etch patterns in conductive, semiconductive and insulating materials was used to examine the surface morphology of resistive thick films, and to modify the surface topography of biomaterials. The ion beam sputter modification of the different materials presently used or under consideration for electronic and implant devices were studied. A Japan Electron Optics Laboratory, model JSM-35 scanning electron microscope was used to examine all the materials tested. 相似文献
54.
Raaja Raajan Angathevar Veluchamy Haluk Beyenal Zbigniew Lewandowski 《Water science and technology》2008,57(12):1867-1872
We used artificial neural networks (ANN) to compute parameters characterising biofilm structure from biofilm images and to interpolate a limited number of experimental data characterising the effects of nutrient concentration and flow velocity on the areal porosity of biofilms. ANN were trained using a set of experimental data characterising structural parameters of biofilms of Pseudomonas aeruginosa (ATCC #700829), Pseudomonas fluorescens (ATCC #700830) and Klebsiella pneumoniae (ATCC #700831) for various flow velocities and glucose concentrations. We used 80% of the data to train ANN and 10% of the data to validate the results, which is routinely carried out as a countermeasure against overtraining. Trained ANN were used to interpolate into the data set and evaluate the missing 10% of the data. To compare ANN accuracy in evaluating the missing data with the accuracies achieved using other interpolation algorithms, we used spline, cubic, linear and nearest-neighbour interpolation algorithms to evaluate the missing data. ANN estimates were consistently closer to the experimental data than the estimates made using the other methods. 相似文献
55.
Marcin Słoma Małgorzata Jakubowska Andrzej Kolek Krzysztof Mleczko Piotr Ptak Adam Witold Stadler Zbigniew Zawiślak Anna Młożniak 《Journal of Materials Science: Materials in Electronics》2011,22(9):1321-1329
This paper presents the results of authors investigations on elaboration of a new thick film composition filled with carbon
nanotubes (CNTs). The polymer composition consists of polymer vehicle, which is the solution of organic resin in certain combination
of solvents, and functional phase—carbon nanotubes well dispersed in the vehicle. The pastes were applied with screen-printing
on several substrates and temperature cured. The properties of obtained layers were characterized. Series of samples were
prepared with different amount of CNTs to evaluate electrical properties. Changes in resistance were investigated during periodic
mechanical and temperature stresses, realized through cyclical bending and rapid temperature change. Tensometric effect was
also investigated. Investigations have proved that polymer composites based on carbon nanotubes exhibit high resilience to
stress factors. Resistance change in function of temperature was also investigated to evaluate temperature coefficient of
resistance (TCR). All this aspects are important for elastic resistors fabrication in printed electronics microcircuits. Resistance
and noise measurements in cryostats have also been involved. 1/f type noise has been observed. Noise intensity, calculated
in decade frequency bands, rises significantly with increasing temperature. Activation energies of thermally activated noise
sources (TANS) have been revealed using low-frequency noise spectroscopy. Relatively large value of negative TCR has been
obtained from resistance versus temperature curve. Calculated dimensionless sensitivity is similar to that observed in cryogenic
temperature sensors. However, bulk noise intensity of resistive layer is larger than obtained for lead containing RuO2 based resistive layers. 相似文献
56.
This paper presents methods for improving the quality of IR images that significantly facilitate the detection of physical and structural non-uniformities in layered objects. The methods are based on wavelets transformations. Both, discrete and continuous wavelet transforms were used. The space-scale representation of thermal image are used for the detection thermal non-uniformities in the objects examined. Examples of recorded and improved images are presented in this paper. 相似文献
57.
Efficient monitoring of mine groundwater conducted with a standard methodology makes the evaluation of the influence of mine water on the environment easier. The paper examines problems of monitoring and proposes a groundwater monitoring system for existing and flooded abandoned mines. The final effect of mine waters monitoring enables ecochemical and economical evaluation. It also makes it possible to select and use the appropriate proecological technologies for mine waters. 相似文献
58.
Sorption of heavy metal ions from aqueous solutions in the presence of EDTA on monodisperse anion exchangers 总被引:2,自引:0,他引:2
Conventional precipitation methods of industrial sewage and wastewater purification are not very effective and are insufficient in many cases. This implies the necessity of searching new, effective methods exploiting cheap, accessible and ecologically safe ion exchangers and sorbents. The paper presents the studies on removal of heavy metal ions — Cu(II), Zn(II), Co(II), Ni(II) and Fe(III) — from aqueous solutions in the presence of EDTA carried out on commercially available, strongly basic monodisperse anion exchangers with the polystyrene skeleton gel, Lewatit MonoPlus M 500; and the macroporous, Lewatit MonoPlus MP 500, which are more widely applied in water purification processes. The research results indicate a high affinity of the Lewatit MonoPlus M 500 and Lewatit MonoPlus MP 500 anion exchangers in the chloride form for copper(II), nickel(II), cobalt(II) and zinc(II) complexes with EDTA. The affinity series for the heavy metal complexes in the 0.001 M M(II)/(III)–0.001 M EDTA and 0.001 M M(II)/(III)–0.001M EDTA–0.001 M–0.002 M NaOH systems were found for the Lewatit MonoPlus M 500 anion exchanger in the chloride form to be as follows: Cu(II) > Ni(II) > Co(II) > Zn(II) Fe(III). In the case of the Lewatit MonoPlus MP 500 anion exchanger in the chloride form there was found the following affinity series: Cu(II) > Co(II) > Ni(II) > Zn(II) Fe(III). These anion exchangers can be applied in the removal of copper(II) complexes from waters and wastewaters. 相似文献
59.
In this paper the embedding of gold clusters in crystallizing bisphenol-A polycarbonate is treated as diffusion with drift in inhomogeneous and changing in time medium. Initially the gold is deposited on the polymer surface, which is subsequently exposed to acetone vapour. The polymer undergoes significant crystallization, induced by diffusing agent, while gold clusters become embedded in its bulk. The paper presents a model of gold dispersion based on Smoluchowski equation. It identifies the driving force of dispersion with the gradient of stress field generated during crystallization. Numerical results of the model are found to be in good agreement with available experimental data obtained by XPS depth profiling technique. 相似文献
60.
Tomasz CiszkowskiIgor Dunajewski Zbigniew Kotulski 《Probabilistic Engineering Mechanics》2011,26(1):67-75
In this paper we propose a new optimality measure for Wireless Sensor Network-based structural monitoring systems. First, we present the results of experiments showing the reasons for random effects in Wireless Sensor Network (WSN) functioning. Then, the formulas for calculating a network’s reputation measure are given. Finally, we conclude with arguments for the application of the reputation-based optimality measure in WSNs. We propose significantly new recommendations for the design and usage of WSNs. 相似文献