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71.
Maria Bercea Silvia Ioan Bogdan C. Simionescu Cristofor I. Simionescu 《Polymer Bulletin》1992,27(5):571-575
Summary Systematic studies on solution properties of ultrahigh molecular weight polymers showed the existence of some special features as compared to usual length polymers. The paper discusses the possible appearance of branched structures in the polymerization process, structures able to influence the mentioned features. From experimental data on poly(methyl methacrylate), poly(butyl methacrylate) and polyacrylonitrile it appears that branching can be excluded, and the very high molecular weight domain considered may be responsible for the modifications observed in the molecular weight dependences on 2>, A2 or []. 相似文献
72.
Giuseppe Spoto Silvia Bordiga Domenica Scarano Adriano Zecchina 《Catalysis Letters》1992,13(1-2):39-44
In this note an exchange procedure of the acidic protons of H-ZSM5 by CuI ions through reaction with CuCl in the gas phase is described. In the so obtained CuI-ZSM5 exchanged zeolite the CuI ions are in well defined configuration and form with NO mono and di-nitrosyl complexes of high structural and spectroscopic quality. The CuI(NO)2 species are transformed at RT into CuII(NO)X (X=O– and/or NO
2
–
) species which could represent an intermediate in NO decomposition. 相似文献
73.
74.
Frank Riedewald Ian Povey Killian Barton Liam Lewis Silvia Santos Maria O'Mahoney Maria Sousa-Gallagher 《化学,工程师,技术》2023,95(6):944-949
Tantalum is the crucial metal of surface-mounted (SMD) tantalum capacitors. Some 50 % of the tantalum mined is consumed in its manufacture, making waste printed circuit boards (WPCBs) an excellent source of secondary tantalum. Yet, its recycling rate is less than 1 %. This paper proposes liberating SMD capacitors from WPCBs by treating them with molten metal or salt. For both processes, the epoxy encapsulation of the capacitors did not disengage from the tantalum core. Furthermore, the molten metal process appears superior to the molten salt one. The tantalum capacitors exit the pyrolysis chamber without salt adhering to them. 相似文献
75.
Dr. Cristina Tintori Ilaria Laurenzana Francesco La Rocca Dr. Federico Falchi Prof. Fabio Carraro Alba Ruiz Prof. José A. Esté Miroslava Kissova Dr. Emmanuele Crespan Prof. Giovanni Maga Prof. Mariangela Biava Dr. Chiara Brullo Prof. Silvia Schenone Prof. Maurizio Botta 《ChemMedChem》2013,8(8):1353-1360
Hematopoietic cell kinase (Hck) is a member of the Src family of non‐receptor protein tyrosine kinases. High levels of Hck are associated with drug resistance in chronic myeloid leukemia. Furthermore, Hck activity has been connected with HIV‐1. Herein, structure‐based drug design efforts were aimed at identifying novel Hck inhibitors. First, an in‐house library of pyrazolo[3,4‐d]pyrimidine derivatives, which were previously shown to be dual Abl and c‐Src inhibitors, was analyzed by docking studies within the ATP binding site of Hck to select the best candidates to be tested in a cell‐free assay. Next, the same computational protocol was applied to screen a database of commercially available compounds. As a result, most of the selected compounds were found active against Hck, with Ki values ranging from 0.14 to 18.4 μM , confirming the suitability of the computational approach adopted. Furthermore, selected compounds showed an interesting antiproliferative activity profile against the human leukemia cell line KU‐812, and one compound was found to block HIV‐1 replication at sub‐toxic concentrations. 相似文献
76.
Dr. Stefan Peukert Dr. Feng He Miao Dai Rui Zhang Yingchuan Sun Dr. Karen Miller‐Moslin Michael McEwan Dr. Bharat Lagu Kate Wang Dr. Naeem Yusuff Aaron Bourret Arun Ramamurthy Dr. Wieslawa Maniara Adam Amaral Anthony Vattay Anlai Wang Ribo Guo Jing Yuan John Green Dr. Juliet Williams Dr. Silvia Buonamici Dr. Joseph F. Kelleher III Dr. Marion Dorsch 《ChemMedChem》2013,8(8):1261-1265
77.
Qusay Alsalhy Amil Merza Khalid Rashid Arman Adam Alberto Figoli Silvia Simone Enrico Drioli 《应用聚合物科学杂志》2013,130(2):989-1004
Hollow‐fiber ultrafiltration (UF) membranes were prepared from blends of poly(vinyl chloride) (PVC) and polystyrene (PS) with a dry/wet phase inversion method. Poly(ethylene glycol) (PEG) and N,N‐dimethylacetamide were used as the additive and solvent, respectively. The effects of the PEG concentration in the dope solution as an additive on the cross sections and inner and outer surface morphologies, permeability, and separation performance of the hollow fibers were examined. The mean pore size, pore size distribution, and mean roughness of both the inner and outer surfaces of the produced hollow fibers were determined by atomic force microscopy. Also, the mechanical properties of the hollow‐fiber membranes were investigated. UF experiments were conducted with aqueous solutions of poly(vinyl pyrrolidone) (PVP; K‐90, Mw = 360 kDa). From the results, we found that the PVC/PS hollow‐fiber membranes had two layers with a fingerlike structure. These two layers were changed from a wide and long to a thin and short morphology with increasing PEG concentration. A novel and until now undescribed shape of the nodules in the outer surfaces, which was denoted as a sea‐waves shape, was observed. The outer and inner pore sizes both increased with increasing PEG concentration. The water permeation flux of the hollow fibers increased from 104 to 367 L m?2 h?1 bar?1) at higher PEG concentrations. The PVP rejection reached the highest value at a PEG concentration of 4 wt %, whereas at higher values (from 4 to 9 wt %), the rejection decreased. The same trend was found also for the tensile stress at break, Young's modulus, and elongation at break of the hollow fibers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 989‐1004, 2013 相似文献
78.
The Atomic Force Microscope (AFM) has become a powerful apparatus for performing real-time, quantitative force measurements between materials. Recently the AFM has been used to measure adhesive interactions between probes placed on the AFM cantilever and sample surfaces. This article reviews progress in this area of adhesion measurement, and describes a new technique (Jump Mode) for obtaining adhesion maps of surfaces. Jump mode has the advantage of producing fast, quantitative adhesion maps with minimal memory usage. 相似文献
79.
Cristhiane Caroline Ferrari Silvia Pimentel Marconi Germer José Maurício de Aguirre 《Drying Technology》2013,31(2):154-163
The purpose of this work was to study the effects of spray-drying conditions on the physicochemical characteristics of blackberry powder using a central composite rotatable design. Inlet air temperature (140–180°C) and maltodextrin concentration (5–25%) were employed as independent variables. Moisture content, hygroscopicity, anthocyanin retention, color, powder morphology, and particle size were analyzed. A higher inlet air temperature significantly increased the hygroscopicity of the powder, decreased its moisture content, and led to the formation of larger particles with smooth surfaces. Powders produced with higher maltodextrin concentrations were less hygroscopic, slightly lighter and less red, and had a lower moisture content. Anthocyanin retention was mainly affected by drying temperature due to the heat sensitivity of the pigment. The optimal processing conditions were an inlet air temperature of 140–150°C and maltodextrin concentration of 5–7%. Overall, these results indicate that good quality powders can be obtained by spray drying, with potential applications for the food industry. 相似文献
80.
This article presents different ways of obtaining hybrid models, which are composed of a simplified phenomenological model and one or several neural networks. As an example, we consider free radical polymerization of methyl methacrylate, achieved through a batch bulk process, in which modeling of conversion and polymerization degrees is analyzed. Kinetics of the process is described through a simplified phenomenological model that does not take into account the gel and glass effects. This last part of the process, which is more difficult to model, is rendered by means of feed-forward neural networks with one or two hidden layers. In the present paper, the hybridization procedure is made in three ways: 1) the neural network corrects the outputs of the simplified kinetic model by modeling the residuals of conversion and polymerization degrees; 2) the neural network provides accurate values of the rate constants to the simplified kinetic model; 3) the neural network models that part of the process in which gel and glass effects appear. It is demonstrated that accurate results are obtained in all three cases, and the hybrid models are easily created and manipulated, especially because they are based on neural networks with quite simple topologies. 相似文献