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111.
The literature has found contradictory results regarding the impact of human resource management on project success. This paper focuses on one important human resource management process – team development – to investigate its importance in the project environment. Results show that most team development practices that work well in the operational business environment do not have a significant influence on project success. However, project duration was found to moderate the relationship between team development and project success: the effectiveness of team development increases in longer projects. The paper identifies and analyzes team development practices that have a positive impact on project success exclusively in long projects. 相似文献
112.
Nanoparticles (NPs) play an increasingly important role in the fabrication of functional advanced materials. Two major steps need to be carried out in order to achieve control of the material properties. First of all, the properties of the single NPs have to be under control, especially in relation to colloidal stability; aggregation and corrosion negate all the benefits associated to the nanoscopic dimensions. Secondly, the assembly process has to be controlled to achieve a material with the desired properties. We propose here to use stabilized ceramic NPs consisting of a magnetite core, coated by a poly(ethylene glycol) (PEG) shell and study their assembly at polar/ non-polar liquid interfaces, en route to fabricating functional NP membranes. These NPs show extraordinary stability in aqueous solutions achieved by anchoring linear PEG chains through an end-terminating nitroDOPA group to their surface. Furthermore, the core and shell sizes of these NPs can be independently varied with ease. We first describe the details of the NP synthesis and stabilization in bulk solutions, discussing the PEG molecular weight needed to achieve bulk stability. Subsequently, we demonstrate self-assembly of these particles at liquid-liquid interfaces (SALI) into monolayers of stable properties. SALI has been chosen as path for the assembly given its suitability for fabricating two-dimensional materials. We report here results from pendant drop tensiometry which illustrate the kinetics of NP adsorption at the liquid-liquid interface and highlight the role played by the molecular weight of the PEG shell in the interfacial assembly. In particular we show that the requisites to ensure particle stability at a liquid interface are more stringent compared to the bulk case. 相似文献
113.
Murtola M Zaramella S Yeheskiely E Strömberg R 《Chembiochem : a European journal of chemical biology》2010,11(18):2606-2612
Several different cationic nonapeptides have been synthesized and investigated with respect to how they can influence the thermal melting of 2′‐O‐methylRNA/RNA and DNA/DNA duplexes. Each peptide has a C‐terminal L ‐phenylalanine unit and is otherwise uniformly composed of a sequence of a specific basic D ‐amino acid that in most cases will be largely charged at neutral pH. These N‐terminal octamer stretches are composed variously of the amino acids D ‐lysine, D ‐diaminobutyric acid (D ‐Dab), D ‐diaminopropionic acid (D ‐Dap), or D ‐histidine. None of the peptides substantially affected the thermal melting of DNA/DNA duplexes, which was in sharp contrast with their effects on 2′‐O‐methylRNA/RNA duplexes. In particular, the peptides based on diaminopropionic and diaminobutyric acid units had strong positive effects on the melting temperatures of the 2′‐O‐methylRNA duplexes (up to 16 °C higher with 1 equivalent of peptide) at pH 7, whereas at pH 6 the effect was even more drastic (ΔTm up to +25 °C). The shorter R groups of the Dap and Dab groups appear to have a better length than lysine for enhancement of the thermal melting of the 2′‐O‐methylRNA/RNA duplex, an effect that is more pronounced at lower pH but substantial even at pH 7, although the Dap derivative is not likely to be fully protonated. The dramatic difference between the influence, or lack thereof, on the 2′‐O‐methylRNA/RNA and the DNA/DNA thermal meltings suggest that, although electrostatic interactions probably play a role, there is another major and structurally dependent component influencing the properties of the duplexes. This is also seen in the observation that the oligo‐Dap and oligo‐Dab peptides give greater melting point enhancements than both the lysine peptide (with a longer side chain) and a β‐linked Dap peptide with a shorter side chain and a longer backbone. 相似文献
114.
Alexandra Manos‐Turvey Esther M. M. Bulloch Dr. Peter J. Rutledge Dr. Edward N. Baker Prof. J. Shaun Lott Dr. Richard J. Payne Dr. 《ChemMedChem》2010,5(7):1067-1079
Mycobacterium tuberculosis salicylate synthase (MbtI), a member of the chorismate‐utilizing enzyme family, catalyses the first committed step in the biosynthesis of the siderophore mycobactin T. This complex secondary metabolite is essential for both virulence and survival of M. tuberculosis, the etiological agent of tuberculosis (TB). It is therefore anticipated that inhibitors of this enzyme may serve as TB therapies with a novel mode of action. Herein we describe the first inhibition study of M. tuberculosis MbtI using a library of functionalized benzoate‐based inhibitors designed to mimic the substrate (chorismate) and intermediate (isochorismate) of the MbtI‐catalyzed reaction. The most potent inhibitors prepared were those designed to mimic the enzyme intermediate, isochorismate. These compounds, based on a 2,3‐dihydroxybenzoate scaffold, proved to be low‐micromolar inhibitors of MbtI. The most potent inhibitors in this series possessed hydrophobic enol ether side chains at C3 in place of the enol‐pyruvyl side chain found in chorismate and isochorismate. 相似文献
115.
A biofilm model for flowing systems in the food industry 总被引:1,自引:0,他引:1
den Aantrekker ED Vernooij WW Reij MW Zwietering MH Beumer RR van Schothorst M Boom RM 《Journal of food protection》2003,66(8):1432-1438
When bacteria attach to the walls of pipelines, they can form biofilms, which can cause the recontamination of food products. In order to quantify such recontamination, a one-dimensional biofilm model was developed taking into account adsorption, desorption, and the growth of cells. The model consisted of two mass balances describing increases in biofilm formation at the wall and the accumulation of cells in the liquid phase. The necessary parameters for the model were obtained in laboratory biofilm experiments. These experiments involved a flowing system and the use of Staphylococcus aureus as a model pathogen and silicon tubing as a testing material. S. aureus was inoculated into the system for 2 h, and then the system was changed to a sterile medium. Both biofilm formation and the release of cells into the flowing liquid were measured until steady-state conditions were reached (for up to 9 days). The experiments were performed in duplicate for different flow conditions (i.e., for Reynolds numbers of 3.2, 32, and 170). It was shown that at higher Reynolds numbers, the biofilm developed faster, probably owing to an increase in the transfer of nutrients to the surface. The proposed biofilm model was capable of describing the data obtained for the three different flow conditions with the use of the specific growth rate in the biofilm and the desorption coefficient as fit parameters. The specific growth rates were 0.16, 0.27, and 0.49 h(-1) for Reynolds numbers of 3.2, 32, and 170, respectively, and the desorption coefficients were about 1% of these values. 相似文献
116.
A. V. Mamchenko I. M. Kosygina O. A. Savchenko 《Journal of Water Chemistry and Technology》2011,33(1):14-19
The paper presents the research results of the regeneration process of carboxylic cation exchanger Lewatit CNP 80, depleted
in water softening, by sulfuric acid in the mode of loosening its layer. It has been established that the theoretical model
of sorption intradiffusion dynamics adequately describes the regeneration process in this mode. The value of the effective
kinetic coefficient of internal mass transfer does not vary in an increase of the expansion of the layer and coincides with
this value in a dense layer. 相似文献
117.
118.
A.A. Kaverzin S.M. Strawbridge A.S. Price F. Withers A.K. Savchenko D.W. Horsell 《Carbon》2011,49(12):3829-3834
The electrical properties of graphene are known to be modified by chemical species that interact with it. We investigate the effect of doping of graphene-based devices by toluene (C6H5CH3). We show that this effect has a complicated character. Toluene is seen to act as a donor, transferring electrons to the graphene. However, the degree of doping is seen to depend on the magnitude and polarity of an electric field applied between the graphene and a nearby electrode. This can be understood in terms of an electrochemical reaction mediated by the graphene crystal. 相似文献
119.
Regional economic dynamics and convergence in the European Union 总被引:4,自引:1,他引:3
Enrique López-Bazo Esther Vayá Antonio J. Mora Jordi Suriñach 《The Annals of Regional Science》1999,33(3):343-370
This paper uses an alternative approach to convergence analysis, which, in our opinion, is richer than those traditionally
proposed. We believe that the evolution of the whole regional distribution is what matters, not that of an average or representative economy, implicit in the or convergence concepts. Moreover, when analyzing inequality among regional economies, geographic space acquires a preeminent
role. We therefore apply spatial association tests recently developed in the spatial econometrics literature and relate them
to convergence analysis. Specifically, we apply this methodology to the analysis of regional dynamics and convergence in the
European Union (EU). In this context, the progress made in the integration process has highlighted the question of economic
disparities at regional level. The process of convergence came to an end in the late seventies, coinciding with major changes
in economic activity. This paper shows how these factors appear to have provoked a regionally differentiated response which,
though significant, did not, in all likelihood, exacerbate the decrease in regional inequalities. 相似文献
120.