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91.
Bleached and unbleached forms of a rosemary oleoresin (RO) in stripped and nonstripped soybean oil behave both as antioxidant
and prooxidant in a light-induced oxidative system. At 0.02 and 0.05% levels, RO had the greatest antioxidant activity, while
at 0.01 and 0.5% levels it had the highest prooxidant activity in both stripped and nonstripped soybean oil. Treatment of
both soybean oil systems with tertiary butylhydroquinone controlled light-induced oxidation of the oil better than did the
oleoresin treatments. The prooxidant activity of the 0.5% RO level was probably due to an excess of prooxidant components
being carried into the oil at that level, whereas the reduced antioxidant activity at 0.01% was probably due to the low initial
level of active antioxidant components being added to the oil.
Published as Journal Series No. 10072, Nebraska Agricultural Research Division, Department of Food Science and Technology,
University of Nebraska, Lincoln, NE 68583-0919. 相似文献
92.
Previous work showed that females of the European tarnished plant bug, Lygus rugulipennis Poppius (Heteroptera: Miridae), produced three chemicals, hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal, and that these were suspected to be components of the female sex pheromone. In field experiments, traps baited with blends of these chemicals dispensed from polyethylene vials and sachets failed to catch significant numbers of males. Here, we report more recent field experiments in which the chemicals were released from glass microcapillary tubes. A blend of hexyl butyrate and (E)-4-oxo-2-hexenal was significantly attractive to male L. rugulipennis. In addition, whereas the mixture of all three components attracted fewer L. rugulipennis males, this tertiary blend captured significantly greater numbers of males of the congeneric species Lygus pratensis than the binary mixture. The possible reasons for the success of the microcapillaries compared with other dispensers are discussed. 相似文献
93.
Small angle scattering (SAS) techniques offer a number of advantages for the investigation of the nature and behavior of porous materials. In particular, with respect to carbons, the essentially non-intrusive nature of SAS means that along with the more traditional, pre- and post-treatment characterization of carbons, in principle, characterization can also be performed in situ during adsorption and activation processes. In the current communication, the application of the techniques of small angle X-ray (SAXS) and neutron (SANS) scattering is reviewed specifically with respect to porosity characterization in carbons. First, the basis of these techniques is presented. More recent applications of SAXS and SANS to carbon porosity are presented, and their relative attributes are contrasted, including the related technique of contrast matching with SANS to distinguish “closed” from “open” porosity, and its application to elucidation of pore development mechanisms. Applications of other related techniques, such as μSAXS and TGA/SAXS, to carbon characterization and porosity development are also discussed. 相似文献
94.
Calculation of mixture properties using the virial equation of state (VEOS) becomes tedious when the expression contains more than the second virial term. This paper describes a derivation procedure which permits relatively simple extension to any number of virial terms. We have used the fugacity derivation as an example of using the new technique and provide an equation for the fugacity coefficient using any number of terms and any number of components. 相似文献
95.
New microporous hybrid organic/inorganic materials were obtained by modification of zeolites using chlorination of their surface,
followed by treatment with a Grignard reagent. Loading of butyl groups and retained crystallinity of ZSM-5 type zeolites was
higher than for zeolites Y. In contrast to zeolites Y, the lattice parameters of zeolites ZSM-5 increased after surface modification.
The obtained hybrid materials on the basis of high-silica zeolites possess a high degree of crystallinity at increased hydrophobicity. 相似文献
96.
Cleland LG Proudman SM Hall C Stamp LK McWilliams L Wylie N Neumann M Gibson RA James MJ 《Lipids》2003,38(4):419-424
Dietary fish oil supplements have been shown to have benefits in rheumatoid arthritis (RA), other inflammatory diseases, and
in cardiovascular disease. As with any medical advice, variability will exist with regard to adherence and consequent biochemical
or pharmacophysiologic effects. The aim was to explore the utility of plasma phospholipid EPA as a measure of n−3 PUFA intake
and response to standardized therapeutic advice given in an outpatient or office practice setting, to increase dietary n−3
PUFA, including a fish oil supplement. Patients with early RA were given verbal and written advice to alter their dietary
n−3 PUFA intake, including ingestion of 20 mL of bottled fish oil on juice daily. The advice included instructions to increase
n−3 PUFA and to avoid foods rich in n−6 PUFA. Every 3 mon, blood samples were obtained for analysis of plasma phospholipid
FA. Plasma phospholipid EPA was used as the primary index of n−3 PUFA intake. A diverse response was seen, with about one-third
of patients achieving a substantial elevation of plasma phospholipid EPA over the 12-mon study period. A third had little
change, with the remainder achieving intermediate levels. Data obtained longitudinally from individual patients indicated
that substantial elevations of EPA (>5% total plasma phospholipid FA) could be maintained for more than 3 yr. Plasma phospholipid
EPA is a convenient measure of adherence to advice to take a dietary n−3 PUFA-rich fish oil supplement. This measure may prove
a useful adjunct to intention to treat analyses in determining the effect of dietary fish oil supplements on long-term outcomes
in arthritis and other chronic inflammatory diseases. It may also provide a guide to the effectiveness of therapeutic and
preventive messages designed to increase n−3 PUFA intake. 相似文献
97.
J. Richard Hall Carolyn A. L. Westerdahl Andrew T. Devine Michael J. Bodnar 《应用聚合物科学杂志》1969,13(10):2085-2096
Polyethylene, polypropylene, poly(vinyl fluoride) (Tedlar), polystyrene, nylon 6, poly(ethylene terephthalate) (Mylar), polycarbonate, cellulose acetate butyrate, and a poly(oxymethylene) copolymer were treated with activated helium and with activated oxygen. Mechanical strengths of adhesive-bonded specimens prepared from treated and from untreated coupons were compared. Polyethylene (PE) and polypropylene (PP) showed the greatest increases in bond strength. Oxygen and helium were both effective with polyethylene, but polypropylene showed no improvement when treated with activated helium. The results with excited helium parallel the effects of ionizing radiation on these two polymers, as does the appearance of unsaturation bands in the infrared (965 cm?1 in PE, and 887 and 910 cm?1 in PP). Active nitrogen produced excellent bond strength with polyethylene but not with polypropylene. Of the remaining polymers examined, Tedlar, polystyrene, and nylon 6 showed the greatest improvement in bondability after treatment, and Mylar showed moderate improvement. Polycarbonate, cellulose acetate butyrate, and the poly(oxymethylene) copolymer gave approximately two-fold increases in lap-shear bond strength. In several cases, significant differences in response to time of treatment and type of excited gas were found. 相似文献
98.
Poly(ethylene ether carbonate) polyols can be modified by chemical reactions with polyglycol modifiers under conditions of elevated temperatures and reduced pressures. The modifier becomes chemically incorporated into the modified polyol and is used to control properties such as moisture sensitivity, CO2 content, Tg, density, etc. in the resultant polyol. However, glycerol cannot be used as a modifier for poly(ethylene ether carbonate) polyols under the same conditions since it reacts with poly(ethylene ether carbonate) polyols by a transesterification reaction sequence to form glyceryl carbonate. As the temperature is increased, the glyceryl carbonate decomposes to yield glycidol and carbon dioxide. These reactions are conveniently followed by 13C-NMR. The preparation of glyceryl carbonate by this process has not been previously reported. 相似文献
99.
The degradation mechanisms of cementitious materials exposed to sulfate solutions have been controversial, despite considerable research. In this paper, two methodologies of image analysis based on scanning electron microscope and chemical mapping are used to analyse Portland cement mortars exposed to sodium sulfate solution. The effects of sulfate concentration in solution and water to cement ratio of mortar, which are considered as the most sensitive factors to sulfate attack, are investigated respectively by comparing the macro expansion with microstructure analysis. It is found that the sulfate concentration in pore solution, expressed as sulfate content in C-S-H, plays a critical role on the supersaturation with respect to ettringite and so on the expansion force generated. 相似文献
100.
Erik L. Gaskin Militza Carrero-Colón Karen A. Hudson 《Journal of the American Oil Chemists' Society》2021,98(2):221-226
Stearic acid is one of five major fatty acids found in soybean oil. It is a fully saturated lipid and is known for neutral or positive effects on LDL cholesterol when consumed by humans. Unfortunately, stearic acid only accounts for about 4% of the total seed oil produced in commodity soybean. Previous work has shown that stearic acid can reach levels as high as 28% of the total oil fraction when the SACPD-C gene, encoding the delta-9-stearoyl-acyl carrier protein desaturase responsible for most of the stearic acid variation in soybean seed, is ablated in combination with other loci. In order to increase stearic acid content and create soybeans with improved utility based on fatty acid composition, we combined mutations in SACPD-C with other mutations in the fatty acid biosynthetic pathway. Soybean plants carrying mutant alleles of both SACPD-C and FAD2-1A produce seed with stearic acid levels from 14% to 21%, and with elevated levels of oleic acid. Soybeans carrying mutations in both SACPD-C and FAD3A or FAD3C have both statistically significantly elevated levels of stearic acid (from 15–21%) and statistically reduced linolenic acid levels. Neither mutant combination appears to affect other agronomic properties such as plant morphology or seed protein levels making this a potentially viable trait. 相似文献