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71.
Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) GS28 and syntaxin 5 can be reciprocally coimmunoprecipitated from Golgi extracts, suggesting that they exist in a protein complex. When Golgi extract is preincubated with soluble NSF attachment proteins (alpha-SNAP) and N-ethylmaleimide-sensitive factor (NSF) under conditions that allow ATP hydrolysis by NSF, GS28 and syntaxin 5 become dissociated. GS28 and syntaxin 5 remain in a protein complex when Golgi extract is preincubated with similar amounts of alpha-SNAP and NSF under conditions that prevent ATP hydrolysis by NSF, suggesting that ATP hydrolysis by NSF is necessary for dissociating the GS28-syntaxin 5 complex. Since preincubation of Golgi extract with either alpha-SNAP or NSF alone has no effect on the GS28-syntaxin 5 complex, a concerted action of alpha-SNAP and NSF therefore mediates the dissociation of the GS28-syntaxin 5 complex. Furthermore, GS28 but not syntaxin 5 is capable of binding to immobilized alpha-SNAP when the GS28-syntaxin 5 complex is dissociated. 相似文献
72.
D. K. H. Chua Y. C. Kog P. K. Loh E. J. Jaselskis 《Canadian Metallurgical Quarterly》1997,123(3):214-222
A neural network approach is used to identify the key management factors that affect budget performance in a project. Field data of project performance has been used to build the budget performance model. This approach allows the model to be built even if the functional interrelationships between input factors and output performance cannot be clearly defined. Altogether eight key determining factors were identified covering areas related to the project manager, project team, and planning and control efforts, namely: number of organizational levels between project manager and craftsmen, project manager experience on similar technical scope, detailed design complete at start of construction, constructability program, project team turnover rate, frequency of control meetings during construction, frequency of budget updates, and control system budget. The model is able to give good predictions even with previously unseen data and incomplete information on the key factors. The model can be used to evaluate various management strategies and thus resources can be effectively deployed to strengthen these aspects of project management. 相似文献
73.
V Olsen K Guruprasad NX Cawley HC Chen TL Blundell YP Loh 《Canadian Metallurgical Quarterly》1998,37(9):2768-2777
Yapsin 1, a novel aspartic protease with unique specificity for basic residues, was shown to cleave CCK13-33 at Lys23. Molecular modeling of yapsin 1 identified the active-site cleft to have negative residues close to or within the S6, S3, S2, S1, S1', S2', and S3' pockets and is more electronegative than rhizopuspepsin or endothiapepsin. In particular, the S2' subsite has three negative charges in and close to this pocket that can provide strong electrostatic interactions with a basic residue. The model, therefore, predicts that substrates with a basic residue in the P1 position would be favored with additional basic residues binding to the other electronegative pockets. A deletion of six residues close to the S1 pocket in yapsin 1, relative to rhizopuspepsin and other aspartic proteases of known 3D structure, is likely to affect its specificity. The model was tested using CCK13-33 analogues. We report that yapsin 1 preferentially cleaves a CCK13-33 substrate with a basic residue in the P1 position since the substrates with Ala in P1 were not cleaved. Furthermore, the cleavage efficiency of yapsin 1 was enhanced for CCK13-33 analogues with arginine residues flanking the P1 position. An alanine residue, substituting for the arginine residue in the P6 position in CCK13-33, resulted in a 50% reduction in the cleavage efficiency. Substitution with arginine residues downstream of the cleavage site at the P2', P3', or P6' position increased the cleavage efficiency by 21-, 3- and 7-fold, respectively. Substitution of Lys23 in CCK13-33 with arginine resulted not only in cleavage after the substituted arginine residue, but also forced a cleavage after Met25, suggesting that an arginine residue in the S2' pocket is so favorable that it can affect the primary specificity of yapsin 1. These results are consistent with the predictions from the molecular model of yapsin 1. 相似文献
74.
Thomas F. McNulty Victor F. Janas Ahmad Safari Roland L. Loh Richard B. Cass 《Journal of the American Ceramic Society》1995,78(11):2913-2916
Piezoelectric ceramic/polymer composites with 1-3 connectivity were made by weaving sized lead zirconate titanate (PZT) fiber bundles through a honeycomb support. Bundles comprised of fine-scale, 20-50 μm green fibers, made using the viscous suspension spinning process, were sized to increase their manageability. The sizing step comprised of soaking the green PZT fiber bundles in an aqueous solution of poly(vinyl alcohol), then pulling the wet fibers through a steel sizing die. Sizing resulted in dense and flexible fiber bundles, which facilitated composite construction and led to composites with increased volume fractons. Sintering, polymer embedding, and machining produced a composite exhibiting 1-3 connectivity. Composites with 10 vol% PZT yilded d 33 values of 230 pC/N and a dielectric constant of 130. 相似文献
75.
Neural-inspired branch predictors achieve very low branch misprediction rates. However, previously proposed implementations
have a variety of characteristics that make them challenging to implement in future high-performance processors. In particular,
the path-based neural predictor (PBNP) and the piecewise-linear (PWL) predictor require deep pipelining and additional area
to support checkpointing for misprediction recovery. The complexity of the PBNP predictor stems from the fact that the path
history length, which determines the number of tables and pipeline stages, is equal to the history length, which is typically
very long for high accuracy. We propose to decouple the path-history length from the outcome-history length through a new
technique called modulo-path history. By allowing a shorter path history, we can implement the PBNP and PWL predictors with significantly fewer tables
and pipeline stages while still exploiting a traditional long branch outcome history. 相似文献
76.
Numerical simulations performed show that polarization self-modulation in suitably designed semiconductor lasers into the tens of GHz frequency region should be possible. The calculations are based on a simple model developed to describe polarization self-modulation in a ring laser cavity with a traveling-wave semiconductor laser amplifier as the gain medium. A set of difference-differential equations is derived and numerically solved. Periodic oscillations in the two polarization modes are obtained as previously reported experimentally. An examination of the various parameters and their roles in maintaining this instability is also conducted. The results indicate that, in an appropriately designed semiconductor laser with a monolithically integrated intracavity TE-TM mode converter, ultrahigh frequency polarization self-modulation to at least 50 GHz should be possible 相似文献
77.
Chee Hoong Loh 《International journal for numerical methods in engineering》1984,20(1):182-186
Bathe's basic algorithm of subspace iteration for the solution of the symmetric eigenvalue problem is improved by including a Chebyshev filtering mechanism. To obtain satisfactory convergence for the largest eigenvalues, a shifting strategy is adopted. The shift factor is approximately computed by the Lanczos process. 相似文献
78.
The nucleotide sequences of the conjugative F plasmid transfer region genes, traV and traR, have been determined. The deduced amino acid sequence of TraV indicated that it may be a lipoprotein; this was confirmed by examining the effect of globomycin on traV-encoded polypeptides synthesized in minicells. An open reading frame that may represent a previously undetected transfer gene, now designated trbG, was identified immediately upstream of traV. The deduced product of traR was found to share amino acid similarity with proteins from the bacteriophages 186 and P2 and with the dosage-dependent dnaK suppressor DksA. 相似文献
79.
80.
The fabrication of submicrometer contacts of Al, PtSi, TiN, and CVD W to both arsenic- and boron-doped junctions using e-beam lithography and photolithography in a mix-and-match mode is described. The contact resistances obtained indicate that this will not be a major barrier for future ULSI scaling. The measured resistance values are compared to those obtained using a 2-D model and the discrepancies are discussed. A generalized scaling law for electromigration at contacts is also developed by taking into account the current distribution in the contact area 相似文献