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41.
Boris Raymond Gaël Guennebaud Pascal Barla Romain Pacanowski Xavier Granier 《Computer Graphics Forum》2014,33(2):313-321
This paper introduces a system for the direct editing of highlights produced by anisotropic BRDFs, which we call anisotropic highlights. We first provide a comprehensive analysis of the link between the direction of anisotropy and the shape of highlight curves for arbitrary object surfaces. The gained insights provide the required ingredients to infer BRDF orientations from a prescribed highlight tangent field. This amounts to a non‐linear optimization problem, which is solved at interactive framerates during manipulation. Taking inspiration from sculpting software, we provide tools that give the impression of manipulating highlight curves while actually modifying their tangents. Our solver produces desired highlight shapes for a host of lighting environments and anisotropic BRDFs. 相似文献
42.
Dale V. Stingley Raymond J. Wrobel 《Journal of the American Oil Chemists' Society》1961,38(4):201-205
Data have been presented which indicate a positive relationship between thetrans-isomer content of a hydrogenated oil and the congeal point, Wiley melting-point, and solids index. It has also been shown
that cottonseed oil and soybean oil undergo substantially the same type of reaction under identical hydrogenating conditions.
This conclusion is based on the relationship oftrans-isomer formation to total reduction in unsaturation up to the point that equilibrium is reached and saturation of thetrans-isomers occurs. This equilibrium was noted at between 60–70 iodine value.
The relationship oftrans-isomer formation to the total reduction in double bonds can be expressed as the hydrogenation index. This is a reliable indication
of the type of reaction taking place up to the point where appreciable hydrogenation of thetrans-isomers occur. 相似文献
43.
Through the study of the effects of concentration, temperature, and molar ration (of paraformaldehyde to cellulose) on solution viscosity and per cent transmittance (at 530 nm), it has been demonstrated that cellulose solutions in dimethyl sulfoxide (DMSO) are readily produced. By heating 1, 2, and 50 to 100 parts by weight of cellulose, paraformaldehyde, and DMSO, respectively, extremely viscose cellulose solutions and gels were prepared. Solutions with concentrations as high as 10% were prepared. However, the optimum conditions to effect complete cellulose solution in DMSO at 75°C were found to be 0.5% cellulose and 0.8 and 1.0% paraformaldehyde. This corresponds to a paraformaldehyde-to-cellulose molar ratio of about 10:1. 相似文献
44.
A large number of studies have been devoted in recent years to the miscibility behavior of linear polyesters with chlorinated polymers, including poly(vinyl chloride) (PVC), chlorinated PVC, chlorinated poly(ethylenes), and copolymers of vinylidene chloride (Saran). However, similar studies with aromatic polyesters are lacking. It is the purpose of this paper to compare the properties of blends made of poly(ethylene terephthalate), poly(butylene terephthalate) or poly(hexamethylene terephthalate) and of various chlorinated polymers. It is shown that a high concentration of chlorine atoms is required to achieve miscibility. Moreover, there is a “miscibility window” in terms of the carbonyl concentration of polyesters, immiscibility being found for carbonyl concentrations outside this window, A similar behavior was observed before for linear polyester/chlorinated polymer blends and for polyester/polycarbonate blends. Solid state small-angle light scattering experiments were also conducted to follow the morphology of the blends as a function of composition. Spherulites were found but their size vary with composition. 相似文献
45.
Raymond L. Venable 《Journal of the American Oil Chemists' Society》1985,62(1):128-133
In W/O microemulsions prepared by adding dry surfactant to a mixture of 85% heptane or toluene and 15% pentanol, then titrating
with water, systems using quaternary ammonium salts have been shown to be capable of solubilizing much larger amounts of water
than systems using the anionic sodium dodecyl sulfate. In homologous series in the range C12 to C16 it would appear that, with one exception, longer chain length quaternary salts are more effective at solubilizing water than
are shorter chain length compounds. With quaternary salts of equal chain length, pyridinium salts are more effective at solubilizing
water at high surfactant concentrations than are corresponding trimethyl salts. 相似文献
46.
The development of adipose tissue in the chick embryo was investigated using two groups of fertile eggs which differed by
1.7-fold in their initial yolk lipid levels. The triacylglycerol content of the subcutaneous adipose depot in both groups
increased dramatically from day 12 of the 21-day embryonic period, attaining a maximal value just prior to hatching. During
this period, the amount of triacylglycerol deposited in the adipose tissue was very highly correlated with the amount of lipid
transferred from the yolk. The triacylglycerol content of the depot was also dependent on the initial yolk lipid content.
During the hatching period, the amount of adipose triacylglycerol remained approximately constant in the group with the higher
initial yolk lipid content but, in the case of the group with the lower initial yolk lipid levels, decreased by approximately
25%. The size distribution of adipocytes isolated from the tissue was determined by computerized image analysis microscopy.
The mean adipocyte diameter increased from approximately 6 to 35 μm between days 12 and 19, irrespective of the initial yolk
content, although development within the eggs with the lower initial yolk content resulted in a decrease in cell size over
the hatching period. Both the triacylglycerol and phospholipid fractions of the isolated adipocytes contained substantial
proportions (approximately 6%, w/w) of docosahexaenoic acid (DHA) at days 12 and 14, and lower levels of this fatty acid at
the later stages. The amount (mg/depot) of DHA in adipose triacylglycerol decreased dramatically over the hatching period.
The amount (mg/brain) of DHA in brain phospholipid increased by more than 5-fold between day 12 of development and hatching.
A possible explanation for the data may be that DHA is preferentially mobilized from adipose tissue in order to deliver the
fatty acid to the developing neural tissues in a form suitable for uptake. 相似文献
47.
This report summarizes some initial results on the use of a perforated brass shim stock support to extend the useful range of dynamic mechanical testing well over 100 degrees above the traditional limiting polymer softening points of Tg or Tm. Weak secondary relaxations were observed above Tg in both polyisobutylene (PIB) and polystyrene (PS) homopolymer, copolymer, and blend systems and above Tm in gutta percha (trans-polyisoprene). The DuPont 981 Dynamic Mechanical Analyzer (DMA)–990 Thermal Analyzer system was used to characterize these weak liquid state processes. The DMA instrument deforms the specimen in flexure, thus minimizing the shear component present in some other techniques. Specimen-coating weights are typically in the range 20–40 mg. The perforations are particularly useful for polymers having low inherent adhesion to metals or systems which are very brittle in the glassy state, e.g., low MW PS's and many methacrylates. 相似文献
48.
When fibrillation occurs during peeling, the normal stress in the adhesive may gradually reduce to zero at the peel front. The shear stress also reduces to zero. Classical beam-spring (or beam-on-elastic-foundation) models do not yield solutions that have these properties. With the use of a beam-on-foundation model combined with a cohesive zone in the neighborhood of the peel front, these properties can be satisfied. In order to obtain analytical solutions, peel tests are considered in which the backing has a small slope and is linearly elastic in the adhered region, and the traction law is assumed to be piecewise linear. Cases are considered with only normal stresses in the adhesive (mode I), only shear stresses (mode II), and both stresses coupled (mixed-mode behavior). Analytical solutions are obtained for displacements of the backing, forces in the backing, and stresses between the adhesive and the backing. 相似文献
49.
50.
Phenomenological softening points were measured on a series of 13 anionic, nearly monodisperse, atactic polystyrenes using a DuPont 943 thermomechanical analyzer (TMA) in a penetration mode. Although TMA cannot identify the nature of the “transition” observed as such, the results obtained support the evidence for the Tg, Tll, and T′ll transition in polystyrene discussed in recent literature. Tg and Tll were found to vary with molecular weight in a systematic manner, while T′ll could only be observed at very high molecular weight. The technique appears to be quite useful in offering rapid and reproducible information on the various transitions in the liquid state of polystyrene. 相似文献