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101.
Ganesh Skandan Nick Glumac Yi-Jia Chen Fredric Cosandey Eric Heims Bernard H. Kear 《Journal of the American Ceramic Society》1998,81(10):2753-2756
The influence of electroless nickel plating on lead-based relaxor ferroelectric multilayer ceramic capacitors (MLCs) was studied by a comparison experiment. It was found that the influence is related to reactions in the electroless plating. It is proposed that adsorbed hydrogen atoms generated in electroless plating can diffuse into the ceramic bodies of MLCs and undergo some reduction reaction with them, resulting in the failure of electroless nickel plating. The implications for the negative influence of electroplating on MLCs and for the degradation in MLCs are also included, in which much attention is paid to the reduction reaction of hydrogen atoms generated by electrolysis of water. 相似文献
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Mandy J. Hetherington Alan Martin Douglas B. MacDougall Keith R. Langley Nick Bratchell 《Food quality and preference》1990,2(4):243-254
Knowledge of the inter-relationships among objective physical and optical measurements and their relation with sensory perception of foods can be applied to improve quality control and consumer acceptance. Changes in the optical and mechanical properties of tomatoes were found to be related to the perceived ripeness of the fruit over a storage period. The sensory attributes and instrumental parameters significant in the assessment of ripening tomatoes were translucency, green, orange, lightness, hue and chroma. The chromatic co-ordinate a* was significantly correlated with the mechanical modulus of the fruit, which in turn was inversely related to ripening associated with colour changes from green to red. It is feasible that mechanical and optical data may be combined to provide an on-line system for the evaluation of ripeness of tomato fruit. 相似文献
105.
Jose Guadarrama Edward L. Dreizin Nick Glumac 《Propellants, Explosives, Pyrotechnics》2016,41(4):605-611
Cylindrical reactive liners filled with powders of aluminum, aluminum‐magnesium alloys, and aluminum‐magnesium powder blends were prepared and initiated by a centrally located explosive charge. The experiments were performed in a cubic chamber. Several transient pressure measurements were taken in addition to the quasistatic pressure caused by the explosion. Results were compared against a reference case with an inert liner filled with aluminum oxide powder. For all reactive liners, an increase in both quasistatic pressure and blast wave strength were observed compared to the case of an inert liner. In experiments with mechanically alloyed Al ⋅ Mg powders, the quasistatic pressure is effectively the same as in experiments with pure aluminum. An improvement in the achieved quasistatic pressure is observed for the liners with a cast alloyed Al ⋅ Mg powder. Most interestingly, a substantial contribution to the air blast indicative of very early reaction occurring in sub‐millisecond time scale is observed for all experiments with reactive liners. The most substantial improvement in the blast characteristics is observed in experiments with mechanically alloyed Al ⋅ Mg powders. While the mechanisms of prompt reactions of metals and alloys remain largely unexplored, the present results highlight the importance of such reactions for reactive liners and other components of energetic systems. 相似文献
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Teresa Gonzalo Dr. Maria Isabel Clemente Louis Chonco Nick D. Weber Dr. Laura Díaz Dr. María Jesús Serramía Rafael Gras Paula Ortega Dr. F. Javier de la Mata Dr. Rafael Gómez Dr. Luis A. Lopez‐Fernández Dr. Maria Ángeles Muñoz‐Fernández Dr. José Luís Jiménez Dr. 《ChemMedChem》2010,5(6):921-929
The ability of dendrimer 2G‐[Si{O(CH2)2N(Me)2+(CH2)2NMe3+(I?)2}]8 (NN16) to transfect a wide range of cell types, as well as the possible biomedical application in direct or indirect inhibition of HIV replication, was investigated. Cells implicated in HIV infection such as primary peripheral blood mononuclear cells (PBMC) and immortalized suspension cells (lymphocytes), primary macrophages and dendritic cells, and immortalized adherent cells (astrocytes and trophoblasts) were analyzed. Dendrimer toxicity was evaluated by mitochondrial activity, cell membrane rupture, release of lactate dehydrogenase, erythrocyte hemolysis, and the effect on global gene expression profiles using whole‐genome human microarrays. Cellular uptake of genetic material was determined using flow cytometry and confocal microscopy. Transfection efficiency and gene knockdown was investigated using dendrimer‐delivered antisense oligonucleotides and small interfering RNA (siRNA). Very little cytotoxicity was detected in a variety of cells relevant to HIV infection and erythrocytes after NN16 dendrimer treatment. Imaging of cellular uptake showed high transfection efficiency of genetic material in all cells tested. Interestingly, NN16 further enhanced the reduction of HIV protein 24 antigen release by antisense oligonucleotides due to improved transfection efficiency. Finally, the dendrimer complexed with siRNA exhibited therapeutic potential by specifically inhibiting cyclooxygenase‐2 gene expression in HIV‐infected nervous system cells. NN16 dendrimers demonstrated the ability to transfect genetic material into a vast array of cells relevant to HIV pathology, combining high efficacy with low toxicity. These results suggest that NN16 dendrimers have the potential to be used as a versatile non‐viral vector for gene therapy against HIV infection. 相似文献
108.
The reinstatement of natural flow regimes is a rapidly emerging issue in river restoration worldwide. In northern Victoria, Australia, efforts are presently underway to restore a natural, intermittent flow regime to several streams which have received perennial diversions for both irrigation and stock and domestic water‐supplies for over 100 years. A pipeline to deliver water to landholders will significantly reduce transmission losses throughout the system allowing irrigation canals and diversion weirs to be decommissioned. The motivation for flow alteration in this system lies primarily in reducing inefficiencies in water delivery which, in turn, will be used to meet escalating demands on water resources. The ecological impact of the flow regime shift on these streams is likely to be substantial. This study utilized an existing artificial hydrological gradient (from perennial to intermittent) in two creek systems, to explore relationships between flow regime and a range of ecological variables. These data provide a benchmark against which to assess ecological changes once flow has been altered and form the basis for predicting changes that can assist future management decisions. Data collected from 10 sites across a strong hydrological gradient detected clear differences in geomorphology, water quality and biotic assemblages (macrophytes, macroinvertebrates and fish). By examining the relationship between flow regime and the distribution of biota we identify both the positive and negative outcomes of restoring naturally intermittent flow regimes within artificially perennial lowland streams. The reinstatement of intermittent flow regimes in artificially perennial streams will continue in many parts of the world as water delivery via these systems becomes increasingly uneconomical. While flow restoration may in principle be regarded as a positive step, these findings emphasize the need to consider fully the ecological consequences of restoring historical hydrological regimes to streams within the context of other human induced catchment disturbances. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
109.
Brominated powdered activated carbon sorbents have been shown to be quite effective for mercury capture when injected into the flue gas duct at coal-fired power plants and are especially useful when burning Western low-chlorine subbituminous coals. X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) have been used to determine information about the speciation and binding of mercury on two commercially available brominated activated carbons. The results are compared with similar analysis of a conventional (non-halogenated) and chlorinated activated carbon. Both the XAS and XPS results indicate that the mercury, though introduced as elemental vapor, is consistently bound on the carbon in the oxidized form. The conventional and chlorinated activated carbons appeared to contain mercury bound to chlorinated sites and possibly to sulfate species that have been incorporated onto the carbon from adsorbed SO2. The mercury-containing brominated sorbents appear to contain mercury bound primarily at bromination sites. The mechanism of capture for the sorbents likely consists of surface-enhanced oxidation of the elemental mercury vapor via interaction with surface-bound halide species with subsequent binding by surface halide or sulfate species. 相似文献
110.
Nick Kalogeropoulos Nikolaos K Andrikopoulos Maria Hassapidou 《Journal of the science of food and agriculture》2004,84(13):1750-1758
The effect of domestic pan‐frying in virgin olive oil (VOO) on the proximate composition, energy content, cholesterol, squalene and fatty acids in the edible portion of six species of finfish, common squid and mussels just caught from several regions of the Aegean Sea (Mediterranean Sea) was investigated. The species selected are traditionally consumed pan‐fried in VOO by the Greeks. On a fresh weight basis, pan‐frying caused significant water loss and increase of total fat, crude protein and energy content. The amount of VOO absorbed during frying ranged from 4.5 to 14.2% of fresh matter, showing a non‐linear negative correlation with initial fat, fish length and fish weight. Cholesterol content increased from 25 to 106 mg 100 g?1 fresh weight (fw) to 33–130 mg 100 g?1 fw after frying. VOO absorbed during frying resulted in a 20–78 times increase of squalene content and in significant alteration of fatty acid composition, the major change being the increase of monounsaturated fatty acids which became predominant in all fried samples. The intakes of fat and major fatty acid classes by consuming the pan‐fried seafood were comparable with the respective average Greek values. Frying in VOO resulted in a two to three times decrease of the atherogenic index and a slightly less decrease of the thrombogenic index. Both indices remained lower than 0.45 in all fried samples. The cholesterol‐saturated fat index and the cholesterol index increased up to twice after frying, ranging between 3.4–9.9 and 2.9–9.3, respectively. From the results obtained it is concluded that fish and shellfish pan‐fried in VOO present a healthy lipid profile in terms of the n‐6/n‐3 ratio, major fatty acid classes and total fat content. Copyright © 2004 Society of Chemical Industry 相似文献