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31.
目的 从土壤中筛选能降解壳聚糖的微生物,并优化其产酶条件。方法利用平板筛选法对采集的土壤中的微生物进行富集培养、初筛和复筛,得到能降解壳聚糖的菌株,并对降解壳聚糖能力最强的菌株进行发酵培养,优化产酶条件。结果筛选出3株产壳聚糖酶菌株,编号为C-01、C-02和C-03,其中,C-01、C-02为细菌,C-03为霉菌。C-01菌株产酶能力最强,其最适产酶条件为:以1%粉末壳聚糖+0.1%葡萄糖为碳源,0.5%(NH4)2SO4+0.5%蛋白胨为氮源,培养基初始pH值8.0,培养温度30℃,菌株接种量2.0%,培养时间48 h。在最适条件下,壳聚糖酶活力可达7.78 U/ml。结论已筛选出1株高产壳聚糖酶的菌株,并优化了其产酶条件,为壳寡糖的生产及应用奠定了基础。 相似文献
32.
33.
Ji‐Kang Jeong Young‐Wook Kim Hye‐Sun Choi Dong Sun Lee Soon‐Ah Kang Kun‐Young Park 《International Journal of Food Science & Technology》2011,46(10):2015-2021
Kimchi was fermented in onggi and other containers at 4 °C for 4 weeks. Two types of onggi were used: glazed and nonglazed onggi. Other containers such as polyethylene plastic containers, polypropylene containers for use in a kimchi refrigerator, stainless steel and glass bottles were used. During the fermentation, kimchi fermented in onggi showed relatively stable acidity change compared with those in the other containers. Also it showed higher lactic acid bacteria multiplication (108–109 cfu g?1 at 4th week) but slower general aerobic bacteria multiplication than the others. The springiness of kimchi fermented in onggi was more than 50% at 4th week, it is higher than the others. Its carbonic acid taste and overall acceptability were excellent in sensory evaluations. The antioxidative and cancer‐cell antiproliferative activities were also greater in kimchi fermented in onggi than the others. Between the two types of onggi, nonglazed onggi showed better results in both properties and functionalities of kimchi. Onggi showed higher gas permeability than polyethylene plastic containers and glass bottles because of its porous structure, and lactic acid bacteria could have benefited from this condition. It possibly contributes to optimal ripening of kimchi resulting in better properties, especially texture and taste, and health functionalities. 相似文献
34.
《Food Reviews International》2013,29(4):317-337
Cereals represent the main crop in Africa (45% of arable land) and make an important contribution to the human diet in this continent. Cereals for humans are not consumed raw. Fermentation technology is widely used in Africa to transform cereals into edible products as well as to preserve and enhance the nutritional and safety aspects of cereals. In general, in Africa, this process is not controlled and is devoid of good manufacturing practices (GMPs). Spoilage and/or pathogenic microorganisms may compromise the final quality when the fermentation is not controlled. This article focuses on the role that the fermentation process could play in creating safe food conditions in Africa. Taking into account the increasing demand for cereals, in particular maize and rice, which contain undesired microorganisms, fermentation can play an important role in creating food security and safety. Here, the authors report a detailed analysis of the cereal market, the main transformation processes used to obtain a variety of products from cereals, the most current information on the microbial ecology of the most important traditional fermented cereals, and the safety aspects of and the technological parameters for the selection of the strains to be used as starters for African cereal-based fermented products. 相似文献
35.
The microbial dynamics and diversity during solid substrate fermentation of cassava, a case study of gari production in West Africa, was investigated. The 16S rDNA gene sequence analysis of the PCR-Denaturing Gradient Gel Electrophoresis (PCR–DGGE) analysis of microbial community DNA and Pulsed Field Gel Electrophoresis (PFGE) of selected isolates as well as culturing techniques using different selective media were used to monitor the bacterial dynamics during cassava fermentation. The V3 variable region of the 16S gene was analyzed and the closest relatives of Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus pentosus, Lactobacillus acidophilus and Lactobacillus casei were identified by sequencing of the DGGE band amplimers. The DGGE amplimers also revealed the succession and dynamics of LAB; there was a progressive increase in their population proportional to the fermentation period. The analysis of the PFGE band patterns showed that five diverse species of LAB were involved in the fermentation. The representative isolate of each of the PFGE clusters was phenotypicaly identified as L. plantarum, L. fermentum and Leuconostoc mesenteroides by the API 50 CHL sugar fermentation profile. These combinations of parameters identified heterofermentative LAB as bacteria that initiated the fermentation, reduced the pH below four and increased the acidity of the fermentation mash. Information such as this is relevant for the development of starter cultures and predictability of the process for traditional fermented foods and to aid their intermediate and large scale production. 相似文献
36.
Meriem Bensmira 《LWT》2010,43(8):1180-1184
In this study, the effects of fermentation conditions (temperature and time) as well as homogenization pressure on the rheology and EPS production in Kefir made from bovine whole milk were investigated. Results showed that the rheological characteristics and EPS production are affected significantly (p < 0.05) by the fermentation temperature but not by the incubation time. Furthermore, the homogenization pressure was found to influence significantly (p < 0.05) the rheology but not the production of EPS in Kefir. 相似文献
37.
Damien Steyer Claude Erny Patricia Claudel Geneviève Riveill Francis Karst Jean-Luc Legras 《Food microbiology》2013
Geraniol produced by grape is the main precursor of terpenols which play a key role in the floral aroma of white wines. We investigated the fate of geraniol during wine fermentation by Saccharomyces cerevisiae. The volatile compounds produced during fermentation of a medium enriched with geraniol were extracted by Stir-bar sorptive extraction and analysed by GC–MS. We were able to detect and quantify geranyl acetate but also citronellyl- and neryl-acetate. The presence of these compounds partly explains the disparition of geraniol. The amounts of terpenyl esters are strain dependant. We demonstrated both by gene overexpression and gene-deletion the involvement of ATF1 enzyme but not ATF2 in the acetylation of terpenols. The affinity of ATF1 enzyme for several terpenols and for isoamyl alcohol was compared. We also demonstrated that OYE2 is the enzyme involved in geraniol to citronellol reduction. Fermenting strain deleted from OYE2 gene produces far less citronellol than wild type strain. Moreover lab strain over-expressing OYE2 allows 87% geraniol to citronellol reduction in bioconversion experiment compared to about 50% conversion with control strain. 相似文献
38.
Ana C. M. de Sena Aquino Juliane M. Pereira Lucas B. Watanabe Edna R. Amante 《International Journal of Food Science & Technology》2013,48(9):1892-1898
This work investigated the pH, titratable acidity and total solids of the cassava starch fermentation water, using the traditional method and a method modified through the addition of glucose. Sour cassava starch production controlled by the characteristic of the fermentation water produced the best product (biscuit specific volume of 7.66 ± 0.41 mL g?1) at 33th day of fermentation in the modified method and at 85th day (biscuit specific volume of 6.53 ± 0.59 mL g?1) in traditional method. But, comparatively to the commercial sour cassava starch (biscuit specific volume of 3.48 ± 0.12 mL g?1), both traditional and modified methods, controlled by titratable acidity of fermentation water, can be retired from the fermentation tank in the 19th and 32th day of fermentation, with biscuit specific volume of 4.75 ± 0.30 and 5.17 ± 0.46 mL g?1, respectively. Determining fermentation time can help to standardise sour cassava starch and to promote future applications of the fermentation water as a raw material. 相似文献
39.
Palraj Kasinathan Dong Won Hwang Uhwang Lee Young Kyu Hwang Jong-San Chang 《Chemical engineering science》2011,(20):4549
Fermentation-derived ammonium lactate was converted into ethyl lactate by decomposition in various organic solvents followed by esterification with ethanol over Amberlyst catalyst. The ammonium lactate was decomposed more efficiently in an organic solvent with high boiling point, where the produced lactic acid was stabilized well as a monomer without oligomerization. However, only the nonreactive phosphate-type solvent such as triethyl phosphate and tributyl phosphate showed a notable ethyl lactate yield in the subsequent esterification reaction compared with dimethyl sulfoxide and N-methyl pyrolidine. The lactic acid yield in ammonium lactate decomposition and the subsequent ethyl lactate yield were also highly dependent on solvent ratio to ammonium lactate, temperature and pressure in ammonium lactate decomposition reaction. The amino acid impurity contained in the fermented ammonium lactate as well as the unreacted ammonium lactate reduced the acid strength of Amberlyst-36, which resulted in the final ethyl lactate yield. 相似文献
40.
The Great East Japan Earthquake that occurred on 11 March 2011 was the largest earthquake in recent Japanese history, and resulted in the generation of large amounts of disaster waste. As a result, many ‘outdoor storage areas’ were established within disaster areas. These piles include various combustible materials such as wood, paper, and plastics, as well as non-combustible materials from destroyed buildings. More than 30 fires occurred in succession at waste storage areas in the Tohoku region, from May to September 2011.One of the causes of these fires is believed to be the proliferation of microorganisms and fermentation of organic material present in the waste piles; the heat generated during fermentation may ultimately result in spontaneous ignition. In this study, we collected samples from outdoor storage areas at which fires have occurred. We then conducted thermal analyses to obtain basic data, and finally developed safety measures to prevent the recurrence of fire. Based on the results, it was reveal that when the amount of heat generated exceeds the amount of heat discharged, the possibility increases for the heat of fermentation that arises from the rotten tatami mats and wood chips and the like to trigger of spontaneous ignition. 相似文献