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61.
62.
A study of the physiological behaviour of the synthetic compound Orthonil (alpha-chloro-beta-(3-chloro-o-tolyl)-propionitrile revealed a strong auxin activity in higher plants. Otherwise, Orthonil appeared not to be a herbicide-auxin. It is metabolized intensively in plant tissues. Among the identified metabolites, two compounds were detected which also exert a high auxin activity. It is concluded that at least a part of the apparent auxin activity of Orthonil may be due to alpha-(3-chloro-o-tolyl) acetic acid, one metabolite of Orthonil. Although Orthonil strongly stimulates elongation growth, this growth is not accompanied by a stimulated ethylene evolution as is the case with other auxins. A possible metabolic pathway of Orthonil is discussed. 相似文献
63.
The capillary white blood cell count and differential, a test easily done in office practice, was used in unexplained febrile illness of infants and toddlers to help distinguish those babies most likely to have bacteremia who would benefit from blood culture and early bacteriologic diagnosis. Four criteria were used as indicators suggestive of bacterial infection: white blood cell count greater than or equal to 15,000/cu mm, total segmented neutrophils greater than or equal to 10,000/cu mm, total band cells greater than or equal to 500/cu mm, and total polymorphonuclear leukocytes (segmented neutrophils plus band cells) greater than or equal to 10,500/cu mm. These measurements were found helpful in separating a small group of bacteremic babies at high risk of complications from a large group of babies who recovered without antibiotic treatment and without complications. There were 146 febrile illnesses recorded in babies 3 to 24 months of age; bacteremia was proven in eight of these. Three or four blood cell count criteria were fulfilled in seven of the eight bacteremic babies and in only ten (7.2%) of the remaining 138 febrile illnesses (P < .001 by chi 2 test). 相似文献
64.
Explored the retrieval-deficit hypothesis by comparing free-recall under cued and noncued conditions in 2 groups of 36 5- and 8-yr-olds. On a 16-word list containing either 2, 4, or 8 categories, Ss received 2 trials of noncued recall. The 2nd trial was immediately followed by a test for cued recall. A comparison between cued recall performance and noncued recall performance on Trial 2 indicates that the younger children benefited more than the older children from the cuing procedure. For both age groups, there were effects of cuing on both the number of categories recalled and the number of items per category recalled. Clustering was observed at both age-levels but appeared unrelated to recall performance. Some of the results are discussed in connection with a retrieval deficit hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
The citric acid fermentation by Aspergillus niger is divided into two consecutive phases, a growth phase when the cells proliferate but do not accumulate citrate, followed by an accumulating phase when they produce citrate but do not proliferate, or else do so at a much reduced rate. When studied in a low sucrose (0.4-0.8%) mpinimal salts medium the growth-accumulation alternative was controlled by the concentration of zinc: high zinc (about 1-2 muM) maintained growth phase, while at low zinc (below 1 muM) growth became limited by zinc deficiency and the cultures passed into accumulating phase. Addition of zinc to accumulating cultures resulted in their reversion to growth phase. Iron, manganese, calcium at concentrations as high as 5-10 muM had no influence on either growth or citrate accumulation. These results suggest that zinc plays a role in the regulation of growth and citric acid accumulation. 相似文献
66.
We explore the possibility of generating high-velocity flows of nanoparticles through flat-rectangular nanochannels, which are only 50% deeper than the diameter of the particles. Using the shear-driven flow principle, 200-nm particles can, for example, be transported through a 300-nm-deep channel at velocities up to 35 mm/s (upper limit of our current setup). Working under high-pH conditions, the velocity of the carboxylated nanoparticles still respects the small-molecule velocity law, despite the high degree of confinement to which the particles are subjected. The high degree of confinement is also found to lead to a reduced band broadening. When injecting sharply delimited particle plugs, the plate heights observed for the flow of 0.2-microm particles through a 0.3-microm channel (with plate heights of the order of 1-2 microm) are, for example, approximately 1 order of magnitude smaller than for the flow of 1.0-microm particles through a 1.4-microm channel. It is also found that the band broadening is, within its statistical variation, independent of the fluid velocity over a large range of particle velocities (5-35 mm/s). The flow method distinguishes itself from pressure-driven field-flow fractionation and hydrodynamic chromatography in that the mean particle velocity is independent of the particle size over the entire range of possible particle to channel diameter ratios. 相似文献
67.
The influence of the detailed design of the sidewall region upon the over-all band-broadening in microfabricated packed-bed or collocated monolithic support structure (COMOSS) columns has been investigated using computational fluid dynamics (CFD) simulation techniques. It is shown that, under unretained solute conditions, very small structural variations of the order of only 5% of the particle diameter can give rise to a 4-fold increase of the band-broadening. A comprehensive study has been made to quantify this effect as a function of the fluid velocity, the particle diameter, the channel widths, and of course, the sidewall region design. Because the sidewall effect can be fully attributed to a mismatch between the flow rates in the column center and in the sidewall region, it is fortunately also quite straightforward to avoid it. A very simple design, yielding band-broadening values identical to that of a hypothetical sidewall-less column for all possible values of the flow velocity, the particle diameter, or the channel width is proposed. 相似文献
68.
Non-destructive Raman and Rayleigh microspectrometries were used to map nanostructural and topological variations across the diameter of the SCS-6 Textron SiC fibre. It is shown for the first time that Rayleigh imaging offers a competitive alternative to AFM measurements for materials containing carbon as a second phase. The Spatial Correlation Model has been used to decompose the SiC Raman spectra into amorphous and crystalline components. Smart Raman images, which contain the calculated structural parameters revealed the nanostructure distribution. A good agreement has been obtained at the nanoscale between these smart images and transmission electron microscopy (TEM) data. A major asset of Raman smart images is to give a non destructive and global view on the crystal quality, grain size and residual stress. The potential and the limitations of the procedure are discussed. 相似文献
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