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111.
Geschäftsmodelle 总被引:1,自引:1,他引:0
Prof. Dr. Daniel Veit Prof. Eric Clemons Prof. Dr. Alexander Benlian Prof. Dr. Peter Buxmann Prof. Dr. Thomas Hess Prof. Dr. Dennis Kundisch Prof. Dr. Jan Marco Leimeister Prof. Dr. Peter Loos Prof. Dr. Martin Spann 《WIRTSCHAFTSINFORMATIK》2014,56(1):55-64
The business model concept, although a relatively new topic for research, has garnered growing attention over the past decade. Whilst it has been robustly defined, the concept has so far attracted very little substantive research. In the context of the wide-spread digitization of businesses and society at large, the logic inherent in a business model has become critical for business success and, hence, a focus for academic inquiry. The business model concept is identified as the missing link between business strategy, processes, and Information Technology (IT). The authors argue that the BISE community offers distinct and unique competencies (e.g., translating business strategies into IT systems, managing business and IT processes, etc.) that can be harnessed for significant research contributions to this field. Within this research gap three distinct streams are delineated, namely, business models in IT industries, IT enabled or digital business models, and IT support for developing and managing business models. For these streams, the current state of the art, suggest critical research questions, and suitable research methodologies are outlined. 相似文献
112.
Samuel J.A. Guieu Anna Maria Manotti Lanfredi Chiara Massera Laura Durn Pachn Patrick Gamez Jan Reedijk 《Catalysis Today》2004,96(4):259-264
Poly(2,6-dimethyl-1,4-phenylene ether) (PPE), which is widely used in high-performance engineering plastics, is obtained by the copper-catalyzed oxidative coupling of 2,6-dimethylphenol. The oxidative polymerizations have been carried out in acetonitrile with structurally related [copper-(N,O-containing ligand)] complexes as the catalyst precursor compounds, which appeared to be of great interest for a better understanding of the factors influencing the catalytic activities. Steric effects (influence of a methyl group close to the metal center; ligands 4–7) or electronic effects (imino versus amino group; ligands 4, 5, 8 and 6, 7, 9, respectively) on the polymerization rates have been demonstrated. The use of mono- or dinucleating ligands has strengthened the proposed mechanism of the reaction involving dinuclear active species. 相似文献
113.
Jan Pospíil 《大分子材料与工程》1988,158(1):221-231
Inherent chemical activity, physical persistence and good compatibility are factors determining the efficiency of a stabilizer observed during the degradation of amorphous and crystalline synthetic polymers. Synthesis of macromolecular stabilizers is one of the ways used to solve the problem of physical persistency of stabilizers under severe aggressive environmental attacks on polymers. General types of macromolecular stabilizers, routes to their synthesis and characteristic examples of macromolecular antioxidants, UV absorbers, hindered amine light stabilizers, flame retarders and biostabilizers, as well as of polyfunctional systems are given. Problems connected with the use of macromolecular stabilizers are mentioned. 相似文献
114.
Jan‐Chan Huang 《应用聚合物科学杂志》2004,91(5):2894-2902
Experimental values of the Flory–Huggins parameter, χ, between polymers and solvents, are frequently used to determine the solubility parameters of the polymers. A method using nonlinear curve fitting of RTχ/V was compared to the linear regression method commonly used. It was found that the formulas for the solubility parameter were the same, but the linear method produced a slightly different entropy term. The nonlinear method gave a lower correlation coefficient and wider confidence intervals and was more effective at distinguishing systems than the linear model. The effect of the deviation of probes in the solubility parameter model is discussed. Using probes with low solubility parameters to measure the polymer solubility parameter gave wider confidence intervals. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2894–2902, 2004 相似文献
115.
Seung Bum Kil Yannick Augros Yves Leterrier Jan‐Anders E. Mnson Andreas Christel Camille Borer 《Polymer Engineering and Science》2003,43(2):329-343
The rheological properties in solution, in shear and in uniaxial elongation of poly(ethylene terephthalate) (PET) reacted together with hyperbranched polymers (HBPs) were investigated. Two different PET grades, of low and high molecular weights, were compounded with sub‐ to over‐stoichiometric concentrations of HBPs of second and fourth pseudo‐generation, and subsequently subjected to a solid‐state polycondensation (SSP). The formation of microgels, which occurs at high HBP concentration, gave rise to a large increase in melt elasticity and a related decrease in melt strength. At low HBP concentrations, the complex viscosity of the unreacted HBP/PET was considerably reduced, thus demonstrating a lubrication effect of the HBP molecules. During SSP, the intrinsic and shear viscosities exhibited a gradual increase, which was similar for both PET and HBP/PET blends, and was correlated to an increase in molecular weight, through linear‐chain extension and branching reactions. The elongational viscosity of the reactive blends was also increased as a function of reaction time, and this increase was much larger in the case of the HBP/PET blends. A 400% increase in melt strength of the PET was obtained by combining SSP and trace amounts of an HBP of second generation, without any decrease in drawability. 相似文献
116.
Peter Van Puyvelde Sachin Velankar Jan Mewis Paula Moldenaers K. U. Leuven 《Polymer Engineering and Science》2002,42(10):1956-1964
The effect of physical compatibilization on the deformation and coalescence of droplets in immiscible polymer blends is discussed. Evidence is provided for the existence of concentration gradients in block copolymers along the interface during deformation. This causes complex changes in droplet shapes during deformation and relaxation. These concentration gradients also result in Marangoni stresses, which stabilize the droplets against deformation and breakup. Coalescence experiments have been performed, varying both the compatibilizer concentration and the shear rate. Existing coalescence models have been evaluated. An empirical extension of Chesters' partially mobile interface model is presented, that treats the effects of Marangoni stresses on the coalescence process as a higher effective viscosity ratio. 相似文献
117.
Preparation of polyesteramides-poly[(ε-caprolactam)-co-(ε-caprolactone)]s by anionic polymerization of ε-caprolactam in the presence of poly(ε-caprolactone) at 150 °C was studied in this paper. ε-Caprolactam magnesium bromide was used as an initiator of polymerization and polymeric materials containing 5-25 wt% ε-caprolactone units were obtained. Thermal methods (DSC and DMA) were employed for characterization of poly[(ε-caprolactam)-co-(ε-caprolactone)]s and their mechanical properties were also evaluated. By introducing the activator with N-acyllactam structure, the polymerization rate increased and it was possible to carry out the polymerization at 110 °C. Mechanical properties of polyesteramides were influenced by both the content of ε-caprolactone units incorporated into copolymer and polymerization temperature. The mechanism of incorporation of poly(ε-caprolactone) is discussed. The results show that it is not possible to restrict exchange transacylation reactions, progressing in the course of polymerization, by kinetic tools. 相似文献
118.
Johannes G. A. Terlingen Gijsbert A. J. Takens Frederik J. Van Der Gaag Allan S. Hoffman Jan Feijen 《应用聚合物科学杂志》1994,52(1):39-53
Poly(acrylic acid) (PAAc) films were treated with either an argon or a tetrafluoromethane (CF4) plasma and subsequently analyzed with X-ray photoelectron spectroscopy (XPS). PAAc films were decarboxylated during both types of plasma treatments. In addition, during the CF4 plasma treatment, the PAAc films became fluorinated. The plasma phase during the argon plasma treatment of PAAc films was investigated with optical emission spectroscopy. It was shown that during this plasma treatment carbon dioxide, water, and possibly hydrogen were liberated from the PAAc surface. By covering the surface of PAAc films with different materials (lithium fluoride, UV fused silica, and glass) during the plasma treatment, it was possible to differentiate between photochemically induced and particle-induced changes of the surface. This method was used to show that decarboxylation during the argon plasma treatment was caused by vacuum UV radiation (wavelength < 150 nm) and the decarboxylation/fluorination during the CF4 plasma treatment was induced by reactive fluorine-containing species from the plasma phase. Furthermore, during both processes, etching of the PAAc surface occurred. Based on these mechanisms, kinetic models were derived that could be used to describe the measured kinetic data adequately. © 1994 John Wiley & Sons, Inc. 相似文献
119.
Zhong Zhiyuan Schneiderbauer Stefan Dijkstra Pieter J. Westerhausen Matthias Feijen Jan 《Polymer Bulletin》2003,50(3):175-182
Summary
Single-site calcium initiators containing chelating tmhd
(H-tmhd = 2,2,6,6-tetramethylheptane-33-dione) ligands
[(THF)Ca(tmhd)]2[-N(SiMe3)2](-tmhd)
(2) and
[(THF)Ca(tmhd)]2[-OCH(Me)Ph](-tmhd)
(3) have been synthesized and
applied for the ring-opening polymerization of L-lactide and
-caprolactone. Both 2 and
3 were highly reactive and
promoted a fast polymerization of L-lactide and -caprolactone
to high monomer conversions under mild conditions (THF as a
solvent, room temperature). More importantly, results showed
that the ring-opening polymerizations of lactides and lactones
initiated by either 3 or
2 in the presence of equivalent
2-propanol are living, to provide polymers and block copolymers
of controlled molecular weights and tailored end-groups. The
polymerizations were first-order in monomer up to high
conversions, in which the in
situ initiating system 2/2-propanol revealed no induction period
and much faster polymerization kinetics as compared to
3. 相似文献
120.
Fábio J. P. Sousa Jan C. Aurich Walter L. Weingaertner Orestes E. Alarcon 《Journal of the American Ceramic Society》2007,90(11):3468-3477
Several kinds of glossiness pattern can be seen on the surface of porcelain stoneware tiles right after the polishing process, as a function of the kinematics performed by the polishing heads. For the newest generation of industrial polishing trains, where a transverse oscillation is included, there is still a great need for literature about the resulting patterns. This paper intends to find the spatial distribution of time under polishing analytically using the kinematics equations involved in the polishing process. The measured values of glossiness collected from three polished tiles are also presented. The importance of adopting a good kinematics for the polishing process has been highlighted, and the equations developed herein are useful tools for further attempts at optimizing the polishing process. 相似文献