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排序方式: 共有311条查询结果,搜索用时 31 毫秒
1.
R.N. ARNOLD K.K. SCHELLER S.C. ARP S.N. WILLIAMS D.M. SCHAEFER 《Journal of food science》1993,58(1):28-33
The effect of long-term feeding (252 days) of three supplemental levels of α-tocopheryl acetate (actual 0, 360 and 1290 IU/head/day) on meat quality was evaluated in Holstein and beef breed steers. Tissue vitamin E concentrations were increased by each increment of supplementation. The color display life of fresh beef under simulated retail conditions was extended 2 to 5 days by vitamin E and lipid oxidation was markedly reduced. Microbial population was not affected by level of supplementation. No deterioration in sensory quality occurred for steaks from supplemented steers that were displayed until the time steaks from unsupplemented steers discolored. 相似文献
2.
J. T. DICKINSON L. C. JENSEN W. DAVID WILLIAMS 《Journal of the American Ceramic Society》1985,68(5):235-240
We present measurements of the electron, positive ion, and photon emission accompanying the fracture in vacuum of poly-crystalline 95/5 lead zirconate-titanate. The intensities of the charged-particle components of this fractoemission are shown to depend strongly on the direction (relative to the direction of fracture) and magnitude of polarization. The most intense emission is observed when the fracture surfaces are perpendicular to the polarization direction. The emission intensity increases monotonically with polarization. These results are interpreted in terms of a model involving charge separation on the fracture surfaces leading to a microdischarge during fracture. Implications to the interpretation of triboluminesence effects are discussed. 相似文献
3.
OPAL J. WILLIAMS G.S. VIYAYA RAGHAVAN VALÉRIE ORSAT JIANMING DAI 《Journal of Food Biochemistry》2004,28(2):113-122
The applicability of microwave irradiation to assist the extraction of capsaicinoids from capsicum fruit was investigated. The procedure involved irradiation of 2 g samples in a closed-vessel followed by gas chromatography of capsaicinoid derivatives. The optimum conditions for extraction were determined to be acetone at 30% power for 7 min irrespective of ground or whole tissue.
The yield of the compounds extracted was significantly greater (P < 0.05) using microwave-assisted extraction (MAE) compared to traditional reflux and shaken flask methods. A single extraction step was efficient in recovering approximately 95% of the total capsaicinoid fraction in 15 min compared with 2 h for the reflux and 24 h for the shaken flask methods. Due to the considerable savings in time and energy as well as reliability, this technique is suitable for fast extraction of capsaicinoids from large samples. 相似文献
The yield of the compounds extracted was significantly greater (P < 0.05) using microwave-assisted extraction (MAE) compared to traditional reflux and shaken flask methods. A single extraction step was efficient in recovering approximately 95% of the total capsaicinoid fraction in 15 min compared with 2 h for the reflux and 24 h for the shaken flask methods. Due to the considerable savings in time and energy as well as reliability, this technique is suitable for fast extraction of capsaicinoids from large samples. 相似文献
4.
The boundedness of the solutions of delay-differential systems with large retardation is proved. The result is obtained by comparing with a system whose exact solutions are obtained. 相似文献
5.
6.
E. L. WILLIAMS 《Journal of the American Ceramic Society》1965,48(4):190-194
Oxygen diffusion in fused silica was measured over the range 850° to 1250°C by means of heterogeneous isotope exchange. In this temperature range and at 1 atm oxygen pressure the diffusion coefficients can be represented by the relation: D = 2 × 10−9 exp (-29 kcal/ RT). The oxygen diffusion coefficients are almost directly proportional to the oxygen pressure which suggests that the oxygen is diffusing in a molecular form. 相似文献
7.
TERRY WILLIAMS 《Construction Management & Economics》2013,31(4):441-447
This paper describes a method for apportioning contingency in a probabilistic network. It distinguishes between two requirements for contingency: for high variance crucial activities, and for high float noncritical activities. This enables a logical two-step apportionment, the first based upon the idea of ‘cruciality’, which has become established as an important indicator of an activity's importance in risk terms, and the second based upon standard ideas about float. A numerical example is given based on data used by previous work, so that a comparison of the methods can be made. 相似文献
8.
A new quantitative thin‐film X‐ray analysis procedure termed the ζ‐factor method is proposed. This new ζ‐factor method overcomes the two major limitations of the conventional Cliff‐Lorimer method for quantification: (1) use of pure‐element rather than multielement, thin‐specimen standards and (2) built‐in X‐ray absorption correction with simultaneous thickness determination. Combined with a universal, standard, thin specimen, a series of ζ‐factors covering a significant fraction of the periodic table can be estimated. This ζ‐factor estimation can also provide information about both the detector efficiency and the microscope–detector interface system. Light‐element analysis can also be performed more easily because of the built‐in absorption correction. Additionally, the new ζ‐factor method has several advantages over the Cliff‐Lorimer ratio method because information on the specimen thickness at the individual analysis points is produced simultaneously with compositions, thus permitting concurrent determination of the spatial resolution and the analytical sensitivity. In this work, details of the ζ‐factor method and how it improves on the Cliff‐Lorimer approach are demonstrated, along with several applications. 相似文献
9.
IN ORDER TO IDENTIFY UNDERLYING DIMENSIONS OF PERSONAL BACKGROUND DATA, 3 SUCCESSIVE FACTOR ANALYSES WERE PERFORMED ON THE RESPONSES OF A VOCATIONALLY HETEROGENEOUS SAMPLE OF 680 MALE SS TO A WIDE SPECTRUM OF COMMONLY USED PERSONAL-BACKGROUND-DATA ITEMS. USING THE FINAL FACTORING, AN ANALYSIS OF VARIANCE OF SCORES DERIVED FROM 15 INTERPRETABLE 1ST-ORDER FACTORS ACROSS 10 OCCUPATIONAL GROUPS SHOWED SIGNIFICANT F RATIOS (P 相似文献
10.