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31.
采用单因素实验结合响应面法,优化了从油茶粕中提取茶皂素的工艺参数。单因素实验最佳条件:乙醇体积分数为70%、提取时间为3 h、提取温度为70℃、料液比为1∶4。在单因素的基础上,选取乙醇体积分数、提取时间、料液比为影响因子,以茶皂素提取得率作为响应值,进行3因素3水平响应面分析。结果表明:茶皂素最佳提取条件是乙醇体积分数为72%、提取时间为3.8 h、提取温度为70℃、料液比为1∶4.5,提取得率预测值为14.54%,验证实测值为14.22%,与预测值相对误差为2.20%。 相似文献
32.
以甘蔗糖蜜为原料,利用糖蜜中的糖类与辛烯基琥珀酸酐反应制备辛烯基琥珀酸糖酯,对其性质进行研究,并以辛烯基琥珀酸糖酯为主要活性成分复配手洗型餐具洗涤剂,对该餐具洗涤剂的性质和去污力进行研究.结果表明,实验制备的辛烯基琥珀酸糖酯稳定性良好,具有较好的起泡性和起泡稳定性.以辛烯基琥珀酸糖酯为主要成分制备的手洗型餐具洗涤剂具有适宜的黏度,良好的起泡性和去污力,符合国标中餐具洗涤剂的要求. 相似文献
33.
34.
Protective solid carriers are commonly added to probiotic cultures prior to drying. Their formulation is not trivial and depends on the drying conditions applied. In this study, we systematically investigated the influence of formulation parameters on the survival of Lactobacillus plantarum WCFS1 after drying. Low molecular weight carbohydrates (less than 2 kDa) with high glass transition temperatures provided the highest level of protection at both low (25 °C) and high (50 °C or higher) drying temperatures. Low molecular weight carbohydrates may provide stabilization by closely interacting with the lipid bilayer of the cell membranes. Meanwhile, carbohydrates with high glass transition temperatures probably provide stabilization via fixation of the cells in a glassy powder. Furthermore, adequate amounts of solid carrier are required to sufficiently stabilize the cells during drying. During drying, crystallization of solid carriers may occur. Depending on the crystal geometry, crystallization can be either beneficial (e.g. with mannitol or sorbitol) or detrimental (e.g. with lactose) to cell survival. Finally, the effect of formulation on cell viability during storage was studied. A decimal reduction time of approximately 300 days was observed when spray dried L. plantarum WCFS1 was stored at temperatures below 40 °C. The outcome of this study was used as a basis to construct a generalized diagram to indicate the combinations of formulation and drying conditions to maximally retain viability and operate dryers at high efficiency. 相似文献
35.
The potential of mixed colloidal dispersions for increasing the bioaccessibility of a hydrophobic bioactive agent (curcumin) was examined. Curcumin was encapsulated within zein nanoparticles (fabricated by antisolvent precipitation) to obtain a high loading capacity and good chemical stability. These protein nanoparticles were then mixed with digestible lipid nanoparticles (fabricated by microfluidization) designed to increase curcumin bioaccessibility by forming mixed micelles in the small intestine. Changes in particle properties (size, charge, and organization) were measured as the mixed colloidal dispersions were passed through a simulated gastrointestinal tract: mouth; stomach; and small intestine. Curcumin bioaccessibility increased with increasing lipid nanoparticle concentration in the mixed colloidal dispersions, which was attributed to an increase in the solubilization capacity of the mixed micelle phase. This study suggests that delivery systems containing mixed colloidal particles (protein and lipid nanoparticles) may be designed to increase the bioaccessibility of lipophilic bioactive agents. 相似文献
36.
37.
An effective method for deproteinization of bioactive polysaccharides extracted from lingzhi (Ganoderma atrum) 总被引:1,自引:0,他引:1
Yi Chen Mingyong Xie Wenjuan Li Hui Zhang Shaoping Nie Yuanxing Wang Chang Li 《Food science and biotechnology》2012,21(1):191-198
Deproteinization procedure is a fundamental step for analyzing polysaccharide from natural plants. In this study, in the course
of refining bioactive polysaccharides from lingzhi (Ganoderma atrum), an effective deproteinization method using lead acetate solution was established by comparing with other available methods.
The percentages of deproteinization, polysaccharide loss, and its antioxidant activities loss were used as the index to evaluate
and optimize the precipitation experimental conditions. The results showed that the modified method, precipitation with the
addition of 0.4–0.52%(w/v) lead acetate, was superior to the others, as evidenced by the highest deproteinization efficiency
(88%), as well as the lowest polysaccharide loss (17%). And notably its antioxidant activity also remained good (loss 15%).
It provides a simple prefractionation step for the analysis of polysaccharide from natural plants. Polysaccharide isolated
by this method is in the native state. Our method may offer a rapid method for removing protein from plant polysaccharides
in large scale. 相似文献
38.
In this study, we propose a set of new algorithms to enhance the effectiveness of classification for 5-year survivability of breast cancer patients from a massive data set with imbalanced property. The proposed classifier algorithms are a combination of synthetic minority oversampling technique (SMOTE) and particle swarm optimization (PSO), while integrating some well known classifiers, such as logistic regression, C5 decision tree (C5) model, and 1-nearest neighbor search. To justify the effectiveness for this new set of classifiers, the g-mean and accuracy indices are used as performance indexes; moreover, the proposed classifiers are compared with previous literatures. Experimental results show that the hybrid algorithm of SMOTE + PSO + C5 is the best one for 5-year survivability of breast cancer patient classification among all algorithm combinations. We conclude that, implementing SMOTE in appropriate searching algorithms such as PSO and classifiers such as C5 can significantly improve the effectiveness of classification for massive imbalanced data sets. 相似文献
39.
《Food Control》2014
Red yeast rice, produced by the fermentation of red yeast (Monascus purpureus) with white rice, has long been used in food colouring and meat preservation in Asia. Recently, powdered red yeast rice and its formulated products, used worldwide as dietary supplements, have the ability of reducing blood-lipid levels in humans. However, some Monascus strains could produce the mycotoxin citrinin as a secondary toxic metabolite so that commercial Monascus products are of a serious concern to the public now. The aim of this study was to obtain information about the occurrence of citrinin in red yeast rice and various commercial Monascus products in Taiwan from 2009 to 2012. A simple and rapid HPLC-fluorescence method was developed to detect citrinin in red yeast rice and Monascus products. The method's performance was acceptable in terms of recoveries, which ranged from 81.2% to 94.3% for citrinin-spiked samples at levels of 0.1, 1 and 10 mg/kg, and the relative standard deviation ranged from 2.5% to 5.7%. The limit of quantification of 0.05 mg/kg was achieved. The survey results showed that among total 302 samples, the incidences of citrinin contamination were 69.0%, 35.1% and 5.7% for red yeast rice (raw material), dietary supplements and red yeast rice processed products, respectively. The mean contamination levels were 13.3, 1.2 and 0.1 mg/kg for red yeast rice (raw material), dietary supplements and red yeast rice processed products, respectively. Such high citrinin contamination rate and level is worthy of note. 相似文献
40.
Hua Xiong Shen‐qi Wang Chun‐qing Bai Qiang Zhao 《International Journal of Food Science & Technology》2014,49(1):91-97
Zero‐trans interesterified fats were produced from camellia seed oil (CSO), palm stearin (PS) and coconut oil (CO) with three weight ratios (CSO/PS/CO, 50:50:10, 40:60:10 and 30:70:10) using Lipozyme TL IM. Results showed that the interesterified products contained palmitic acid (34.28–42.96%), stearic acid (3.96–4.72%), oleic acid (38.73–47.95%), linoleic acid (5.92–6.36%) and total medium‐chain fatty acids (MCFA)s (∑MCFAs, 5.03–5.50%). Compared with physical blends, triacylglycerols of OOO and PPP were decreased and formed new peaks of equivalent carbon number (ECN) 44 in the interesterified products. The product CPC3′ showed a slip melting point of 36.8 °C and a wide plastic range of solid fat content (SFC) (45.8–0.4%) at 20–40 °C. Also, the major β′ form was determined. These data indicated that the zero‐trans interesterified fats would have a potential functionality for margarine fats. Subsequently, the antioxidative stabilities of interesterified products with the addition of α‐tocopherol (α‐TOH) and ascorbyl palmitate (AP) were investigated. The results indicated that AP had a dose‐dependent effect at concentrations of 100, 200 and 400 ppm. 相似文献