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31.
乳铁蛋白和乳铁素的抗菌活性比较 总被引:2,自引:1,他引:2
牛乳铁蛋白是从牛乳中提取出来的一种铁结合性糖蛋白,牛乳铁素是从牛乳铁蛋白N-端水解下来的25个氨摹酸残荩。它们具有多种乍物学功能,其中的广谱抗菌性尤为引人注目。本实验以牛初乳中提取的乳铁蛋白及其水解产物乳铁素为研究对象,选取大肠杆菌为实验菌株,进行铁饱和乳铁蛋白和缺铁性乳铁蛋白、乳铁素对大肠杆菌生长抑制的比较研究。研究结果表明:铁饱和乳铁蛋白、缺铁性乳铁蛋白和乳铁索的最小抑菌浓度分别为6mg/ml、3mg/ml和15μg/ml,乳铁素的最小杀菌浓度为30μg/ml。乳铁蛋白水解后,经纯化获得的乳铁素,其抗菌能力较缺铁性乳铁蛋白增加200倍,较铁饱和乳铁蛋白增加400倍。 相似文献
32.
P. C. Houtsma J. C. de Wit F. M. Rombouts 《International journal of food microbiology》1993,20(4):247-257
Pathogens and spoilage organisms occuring in meat products were screened in laboratory media, according to a method of Eklund (1983), in order to determine the specific inhibitory effect of lactate on growth of these microorganisms under optimum growth conditions (pH 6.5, 20°C). In general, Gram-positive bacteria were more sensitive towards lactate than Gram-negative bacteria. It was shown especially, that strains that were able to grow at water activities of 0.95 and below in the presence of NaCl (Staphylococcus aureus, Listeria monocytogenes, Brochothrix thermosphacta) were inhibited by sodium lactate (NaL). It appeared, that yeasts were resistant to large amounts of NaL (> 10% w/v). However, NaL had a specific inhibitory effect on growth of these organisms when compared to the effect of NaCl. These results indicate that lactate addition to food products with a pH near neutrality offers good prospects for shelf life prolongation. 相似文献
33.
《腐蚀工程科学与技术》2013,48(4):257-266
AbstractThe deep sea corrosion of ferrous alloys that undergo uniform corrosion without forming a passive layer is related to the amount of dissolved ox ygen available in the sea water. The performance of some ferrous alloys at depths of 500, 1200, 3500, and 5100 m in the Indian Ocean has been studied. The results of atomic absorption spectroscopy have revealed that the corrosion product present on mild steel coupons is FeOOH. The results of experiments in shallow water have shown that micro- and macrobiological growths play a significant role in the corrosion of ferrous materials. However, in deeper waters, the absence of macrofouling was evident, and corrosion was not related to any biological product but mainly to the electrochemical reaction of these alloys with sea water. The results of morphological studies by SEM on the surfaces of ex posed specimens are also presented. 相似文献
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Elettaria cardamomum is one of the most broadly used spices in Moroccan gastronomy. Its antimicrobial activity against both Gram-positive and Gram-negative bacterial species was demonstrated. Likewise, its toxicity was investigated on Swiss albinos mice. Daily, mice were treated orally with 0.003 and 0.3 mg during 7 days. Plasmatic markers and antioxidant defence systems were assessed and histological alterations were evaluated. A significant increase in creatine phosphokinase level was observed. The microscopic evaluation shows that E. cardamomum induce morphological perturbation in mice’s heart. The results show also an inhibitory effect of glyceraldehyde 3-phosphate dehydrogenase and an important increase in the level of thiobarbituric acid reactive substances, succinate dehydrogenase and catalase activities. Results show that E. cardamomum induces toxicity at 0.3 mg/g mouse and affect energy metabolism and oxidative stress. 相似文献
35.
Sheng-Hsien Lee Ku-Shang Chang Min-Sheng Su Yung-Sheng Huang Hung-Der Jang 《Food Control》2007,18(12):1547-1554
Chinese medicinal plant extracts were screened against some fungal strains, such as Aspergillus niger, Botrytis cinerea, Fusarium moniliforme, Glomerella cingulata, and Phyllosticta caricae. Plants were extracted with hot water, 80% methanol or acetone. Aliquots of the extracts at variable concentrations were then incubated with different fungal strains, and the minimum inhibitory concentrations (MICs) of each plant extract determined. In this study, the methanol extracts of Cinnamomum cassia had MIC values of 13.3 mg ml−1, when tested against F. moniliforme and P. caricae. The acetone extracts of C. cassia had MIC values of 8.3 mg ml−1 and 10 mg ml−1 respectively, when tested against B. cinerea and G. cingulata. The hot water extracts of C. cassia inhibited significantly the growth of A. niger, B. cinerea, F. moniliforme, and P. caricae with MIC values at 10, 11.7, 5, and 6.7 mg ml−1 respectively. The acetone extracts of Curcuma longa inhibited effectively P. caricae with the MIC value at 6.7 mg ml−1. To determine the stability, various plant extracts were stored at 4 and 25 °C over a period of one month and their effects on fungal growth examined. Results show that the acetone extracts of Cu. longa and Coptidis rhizoma maintained their activity against fungal strains when stored at 4 °C, but not at 25 °C. The methanol extracts of C. cassia lost a great portion of inhibitory activities but not all, after stored at 4 °C and 25 °C for one month. The effect of various combinations of these extracts on antimicrobial activity has also been examined. The combinations of herb extracts showed higher inhibitory effect towards tested fungi than that of individual extract. Results from these findings suggest that these herbal extracts may be used as natural antifungal agents to inhibit growth of foodborne pathogen. 相似文献
36.
求解最大内切圆的一种新方法 总被引:5,自引:1,他引:4
提出了一种求解最大内切圆的新方法,给出了最大内切圆圆心坐标值的计算公式,该方法的基本思路是:首先在被测轮廓上选取初始三点,并保证这三点构成一个锐角三角形;接下来通过给出的公式计算出这三点所在圆的圆心坐标值,被测轮廓各点到该圆心的距离序列;最后判断该圆半径是否等于上述距离序列中的最小值,如果条件不满足,用最短距离所对应的被测轮廓点代替上述三点之一,并保证新的三点仍然形成一个锐角三角形,然后重复上述计算和判断过程,直至条件满足。最后一次计算所得到的圆心恰好是被测轮廓的最大内切圆圆心,该方法的优点在于不存在原理误差,速度快,一般二、三次计算即可,给出了程序流程图。 相似文献
37.
Farhaan Hafeez Xiaoying Hui Marc Selner Bert Rosenthal Howard Maibach 《Drug development and industrial pharmacy》2014,40(6):838-844
Context: Onychomycosis is a common fungal infection of the nail plate and bed that affects up to 14% of the population and can have a substantial impact on the quality of life of those affected.Objective: This study compared the onychopharmacokinetics, nail absorption, nail distribution, and nail penetration of [14C]-ciclopirox dissolved in novel lipid diffusion enhancers with that of a commercial ciclopirox nail lacquer using the in vitro finite dose model.Materials and methods: The penetration rate of ciclopirox was determined by applying doses of topical formulation twice daily to human nail plates for 11?d. Drug absorption was then measured by monitoring its rate of appearance in each nail layer and in the cotton pad/nail supporting bed.Results: After a multiple day treatment, cumulative concentrations of ciclopirox formulated with lipid enhancers in the deep nail layer and the nail bed were significantly greater than cumulative concentrations of the commercial ciclopirox lacquer (p?0.001) as well as several orders of magnitude greater than the minimal inhibitory concentration (MIC) deemed necessary to inhibit the growth of the causative dermatophyte species.Conclusion: When formulated with lipid enhancers, the amount of ciclopirox in the ventral/intermediate layer and supporting bed dramatically exceed the inhibitory concentration of ciclopirox for the most common onychomycosis organisms. These results suggest that topical ciclopirox with lipid enhancers has the potential to be an effective topical treatment for onychomycosis, and the lipidic pathway of the nail can be utilized as a means of effective transungual delivery. 相似文献
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