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61.
The characterization of a lithium supersonic nozzle beam has been made using spectroscopic techniques. It is found that at a stagnation pressure of 5.3 kPa (40 Torr) and a nozzle throat diameter of 0.4 mm the ground state vibrational population of Li(2) can be described by a Boltzmann distribution with T(v)= (195+/-30) K. The rotational temperature is found to be T(r)= (70+/-20) K by band shape analysis. Measurements by quadrupole mass spectrometer indicate that approximately 10-mol. % Li(2) dimers are present far downstream for an oven body temperature of 1370 K in the supersonic nozzle expansion. This measured mole fraction is in agreement with the existing dimerization theory. 相似文献
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64.
Electricity generation by Rhodopseudomonas palustris DX-1 总被引:4,自引:0,他引:4
Bacteria able to generate electricity in microbial fuel cells (MFCs) are of great interest, but there are few strains capable of high power production in these systems. Here we report that the phototrophic purple nonsulfur bacterium Rhodopseudomonas palustris DX-1, isolated from an MFC, produced electricity at higher power densities (2720 +/- 60 mW/m2) than mixed cultures in the same device. While Rhodopseudomonas species are known for their ability to generate hydrogen, they have not previously been shown to generate power in an MFC, and current was generated without the need for light or hydrogen production. Strain DX-1 utilizes a wide variety of substrates (volatile acids, yeast extract, and thiosulfate) for power production in different metabolic modes, making it highly useful for studying power generation in MFCs and generating power from a range of simple and complex sources of organic matter. These results demonstrate that a phototrophic purple nonsulfur bacterium can efficiently generate electricity by direct electron transfer in MFCs, providing another model microorganism for MFC investigations. 相似文献
65.
Inhibition of the behavioral responses of maleEpiphyas postvittana moths by theZ isorner of the major component of the sex pheromone,E11-14: OAc, was studied in a wind tunnel. Inhibition was detectable at a Z isomer concentration of 10% that of the major component and was greatest when it was added to the same source as the pheromone. Inhibition declined rapidly as the inhibitor was moved across-wind away from the pheromone source but was largely maintained when the sources were separated upwind or downwind. The results showed that the insects possess a high degree of temporal resolution for odor plumes of different composition. 相似文献
66.
Moossavi S Tuttle AB Vachharajani TJ Plonk G Bettmann MA Majekodunmi O Russell GB Regan JD Freedman BI 《Hemodialysis international. International Symposium on Home Hemodialysis》2008,12(1):80-84
The need for reliable, long-term hemodialysis vascular access remains critical. To determine the long-term outcomes of transposed basilic vein arteriovenous fistulae (BVT) and their comparability with other vascular accesses, we determined retrospectively the primary and secondary patency rates in 58 BVT and in a total of 58 arteriovenous fistulae (AVF) and arteriovenous grafts (AVG) at a single center. Fifty-eight BVT were placed in 57 individuals, 69% after prior vascular access failure. Ten BVT failed before initial use and 2 patients expired with functioning accesses before dialysis initiation. In all 58 BVT, 46.8+/-10.8% functioned at 3 years, with median survival 30.8 months. Limiting analyses to the 46 BVT that were ultimately accessed, 3-year primary and secondary patency rates were 38.3+/-7.7% and 56.5+/-12.6%, respectively. Lower ejection fraction (p=0.054) and greater numbers of prior permanent dialysis catheters (p=0.005) were present in those with failed BVT. Compared with AVF, BVT had similar 3-year primary and secondary patency rates. The secondary patency rate was significantly better for BVT vs. AVG over the observation period; at 3 years, the rates were 56.5+/-12.6% vs. 9.1+/-6.0% (p=0.002), respectively. Basilic vein arteriovenous fistulae are valuable hemodialysis accesses. Although nearly 20% of newly placed BVT will not function before first use, those that are functional have median survivals exceeding 6 years, and 38% will not require intervention within 3 years of initial use. 相似文献
67.
A new method for fabrication of RNA microarrays is described. The approach involves cohybridization of a short, biotinylated DNA oligonucleotide and an RNA probe sequence to DNA templates spotted onto a master array. Next, the short DNA sequence and the RNA probe are linked using a T4 DNA ligase. Finally, a poly(dimethylsiloxane) (PDMS) monolith modified on the surface with streptavidin is brought into conformal contact with the master array. This results in binding of the biotinylated DNA/RNA oligonucleotides to the PDMS surface. When the two substrates are mechanically separated, the DNA/RNA oligonucleotides transfer to the PDMS replica, and the DNA oligonucleotides remaining on the master array are ready to template another RNA replica array. This sequence can be repeated for at least 18 cycles using a single master array. RNA arrays consisting of up to three different oligonucleotide sequences and consisting of up to 2500 individual approximately 70 microm spots have been prepared. 相似文献
68.
V. Chechik R. M. Crooks C. J. M. Stirling 《Advanced materials (Deerfield Beach, Fla.)》2000,12(16):1161-1171
Self‐assembled monolayers (SAMs) are excellent models for studying interfacial reactions. Here monolayer chemistry is reviewed, focusing on the features that have no analogues in solution chemistry. The growth of surface‐attached polymers, intrafilm reactions, chemistry, photochemistry and reactivity issues are all discussed. 相似文献
69.
Daniel Dennett's philosophical abolition of mind is examined with reference to its methodology, intent, philosophic origins, and internal consistency. His treatment of the contents of perception and introspection is shown to be derivative from realist reductionist misinterpretations of physics, physiology, and phenomenology of perception. In order to rectify inconsistencies of that realistic paradigm devolved from psycho-neural identity theory of mid-twentieth century, Dennett radicalizes its logic and redefines even veridical phenomenology of exteroception to be "illusory." This measure in extremis still does not save the appearances of his predecessors, nevertheless, for Dennett tacitly presupposes the existence of veridical phenomenology in his very treatment of non-veridical sensory phenomena that he uses to argue analogically from, to thereby suggest the plausibility of a parallel illusoriness of veridical phenomena of perception and introspection. This inhering inconsistency renders unsound Dennett's radical extension of the logic of identity theory, and ironically shows up the persistence of mental phenomenology that extant reductionism appears so desirous to argumentively eliminate. Nonetheless there is much to be learned from such an analysis of Dennett's purported elimination of mental contents, for a generalization of our critique throws light on the occult assumptions underlying realism and reductionism since early identity theory and its variants, and upon the possible viability of that programme as a whole. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.
The aim of this study was to evaluate the suitability of Methylene Blue (MB) and Vitamin B12 (Vit-B12) as water soluble inner aqueous phase (W1) markers for measuring the encapsulation efficiency and stability of water-in-oil-in-water (W1/O/W2) double emulsions stabilized by sodium caseinate (NaCN). The encapsulation efficiency and stability were determined by centrifugation of the double emulsion to separate the cream phase (W1/O) and the outer aqueous phase (W2) and measuring the concentration of marker in W2 by absorbance spectrophotometry. To validate this method the marker concentration measurable and the stability of the marker in W2 were measured. Both markers could be accurately measured in W2 and there was no change in the concentration of marker on storage of a W2 solution for 7 days at 45 °C. The recovery yields of MB and Vit-B12 in the recovered W2 of an oil-in-water (O/W2) emulsion, determined using the procedure normally used for measuring encapsulation efficiency and stability, were 78% and 99%, respectively, and 52 and 100%, respectively. Double emulsions had encapsulation efficiency of 61.9 ± 21.4% and 16.6 ± 1.1% and encapsulation stability of 62.0 ± 22.6% and 10.7 ± 0.7% for MB and Vit-B12, respectively. Recovery yield and encapsulation efficiency/stability data for MB indicate that it is not a suitable marker for measuring the encapsulation properties of NaCN stabilized double emulsions while similar data for Vit-B12 indicate that it is a suitable marker for studying the encapsulation properties of double emulsions stabilized with NaCN. Methods used in other studies to measure encapsulation properties of double emulsions are discussed in light of the results obtained in this study. 相似文献