全文获取类型
收费全文 | 3344篇 |
免费 | 198篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 87篇 |
综合类 | 5篇 |
化学工业 | 834篇 |
金属工艺 | 71篇 |
机械仪表 | 104篇 |
建筑科学 | 118篇 |
矿业工程 | 8篇 |
能源动力 | 137篇 |
轻工业 | 547篇 |
水利工程 | 17篇 |
石油天然气 | 16篇 |
无线电 | 223篇 |
一般工业技术 | 799篇 |
冶金工业 | 72篇 |
原子能技术 | 13篇 |
自动化技术 | 492篇 |
出版年
2023年 | 26篇 |
2022年 | 39篇 |
2021年 | 81篇 |
2020年 | 74篇 |
2019年 | 83篇 |
2018年 | 130篇 |
2017年 | 122篇 |
2016年 | 155篇 |
2015年 | 106篇 |
2014年 | 167篇 |
2013年 | 363篇 |
2012年 | 232篇 |
2011年 | 253篇 |
2010年 | 209篇 |
2009年 | 143篇 |
2008年 | 154篇 |
2007年 | 132篇 |
2006年 | 104篇 |
2005年 | 61篇 |
2004年 | 42篇 |
2003年 | 56篇 |
2002年 | 42篇 |
2001年 | 32篇 |
2000年 | 38篇 |
1999年 | 32篇 |
1998年 | 32篇 |
1997年 | 27篇 |
1996年 | 31篇 |
1995年 | 23篇 |
1994年 | 30篇 |
1993年 | 27篇 |
1992年 | 24篇 |
1991年 | 21篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 13篇 |
1985年 | 32篇 |
1984年 | 34篇 |
1983年 | 28篇 |
1982年 | 24篇 |
1981年 | 37篇 |
1980年 | 33篇 |
1979年 | 25篇 |
1978年 | 25篇 |
1977年 | 20篇 |
1976年 | 22篇 |
1975年 | 14篇 |
1974年 | 11篇 |
1973年 | 14篇 |
1972年 | 14篇 |
排序方式: 共有3543条查询结果,搜索用时 15 毫秒
81.
Z. Mandić Milena L. Mandić Jerica Grgić D. Hasenay Z. Grgić 《European Food Research and Technology》1995,201(3):209-212
Selenium levels in human milk in the winter period ranged from 5.3 μg/l to 23.8 μg/l, the mean value being 11.0 μg/l. The nursing women were divided into several groups according to the results of a questionnaire, i.e. according to their social status (refugees or otherwise), number of deliveries, post partum days, the weight they had gained during pregnancy, their age and smoking habits. The mean levels of selenium for each group are presented. Selenium was determined by hydride generation atomic absorption spectrometry. 相似文献
82.
Branislav Borovac Miomir Vukobratović Dragan Stokić 《Mechanism and Machine Theory》1983,18(2):113-122
The paper considers the influence of the complexity of the mathematical model of actuators on control synthesis and simulation of movements on a digital computer. It presents the results of the simulation of dynamics of two mechanical manipulation configurations powered by electromechanical and hydraulic actuators. 相似文献
83.
I. Budić-Leto T. Lovrić J. Gajdoš Kljusurić I. Pezo U. Vrhovšek 《European Food Research and Technology》2006,222(3-4):397-402
Identification of anthocyanins in the wine made of the Croatian autochthonous grape variety of Babić (Vitis vinifera L.) was carried out and their profile was determined by means of high-performance liquid chromatography with diode array
and mass spectrometric detection. Dependence of anthocyanins content and profile on maceration treatment conditions was investigated.
Statistically significant differences of anthocyanins concentration in wines Babić produced by various maceration treatments
were confirmed by the use of multivariate analysis of variances. The investigation results indicated that the maceration temperature
exerts higher influence on anthocyanins concentration than the duration of maceration. In addition, on the basis of anthocyanin
composition and using different multivariate statistical analyses, differentiation of wines Babić according to maceration
treatments was procured. 相似文献
84.
Bogovic Matijasić B Narat M Zoric Peternel M Rogelj I 《International journal of food microbiology》2006,107(1):92-96
The ability of Lactobacillus (Lb.) gasseri K 7 to inhibit adhesion of Escherichia coli O8:K88 to intestinal mucosa was studied on cultured Caco-2 cells and ex vivo on pigs' small intestinal tissue. Lactobacilli were added simultaneously with E. coli, before E. coli and after E. coli for competition, exclusion and displacement assays. The concentration of lactobacilli on fully differentiated Caco-2 cells was 4.5+/-0.3 x 10(8) cfu/well, while the concentration of E. coli varied from 1.5 x 10(6) to 4.3 x 10(8) cfu/well. The number of E. coli adhered to Caco-2 monolayer (cfu/well) was lineary correlated (R(2)=0.97) to the concentration of added cells. In the assay simulating exclusion, E. coli adhesion was reduced by Lb. gasseri K 7 strain by 0.1 to 0.6 log cfu/well. The binding of E. coli was inhibited even more when incubated simultaneously with lactobacilli, particularly at the lowest concentration of E. coli (ratio E. coli/lactobacilli 1:248), where five-times reduction (or 0.7 log) was observed. When adhesion to tissue derived from pigs' jejunum was tested, concentration of E. coli was constant (6.9+/-0.14 x 10(7) cfu/ml), while the concentration of Lb. gasseri K 7 was 5.9 x 10(7) and 1.3 x 10(7) cfu/ml in two independent experiments, respectively. The adhesion of E. coli and Lb. gasseri K 7 cells to jejunal mucosa was similar (1.0+/-0.17 x 10(6) and 1.54+/-0.10 x 10(6) cfu/cm(2)) when the concentrations of single strains in suspensions were approximately the same. No significant competition, exclusion or displacement of E. coli by lactobacilli was observed on jejunal tissue. In conclusion, Lb. gasseri K 7 was found to be effective in reducing E. coli adhesion to Caco-2 enterocytes, but it was not able to do so in ex vivo conditions tested for pig jejunal tissue. 相似文献
85.
86.
Novaković MM Stevanović SM Gorjanović SŽ Jovanovic PM Tešević VV Janković MA Sužnjević DŽ 《Journal of food science》2011,76(4):C663-C668
This study was conducted to investigate the influence of different drying treatments on antioxidant (AO) activity and phenolic content of raspberry (Rubus idaeus), cultivar Willamette. Whole raspberry fruits were dried convectively (air-drying), osmotically, and freeze-dried. Acetone-water extracts of fresh and dried raspberries were assessed for total phenolic content by standard Folin-Ciocalteau method. Two AO assays were applied, a recently developed direct current (DC) polarographic assay based on decrease of anodic oxidation current of hydrogen peroxide and widely used radical scavenge against the 1,1-diphenyl-2-picrylhydrazyl (DPPH). Strong correlation has been obtained between both AO assays and total phenolic content. In addition, some individual phenolic compounds present in raspberry have been assessed using DPPH and DC polarographic assay. Comparison and evaluation of drying methods has been based on preservation of AO activity and total phenolic content. Obtained results confirmed superiority of freeze-drying; convective drying caused slight changes while osmotic dehydration showed a significant decrease of phenolic compounds and AO activity. 相似文献
87.
In 2007 and 2008, a monitoring study was carried out in Poland to examine the occurrence of thermotolerant Campylobacter spp. in raw and cooked chicken products available on the retail market. A total of 912 samples were tested: 443 samples of raw chicken meat, 146 samples of giblets, and 323 ready-to-eat poultry products (150 samples of spit-roasted chicken, 56 samples of smoked chicken, and 117 samples of paté and cold meats). A high level of contamination of raw chicken meat (51.7% of samples) and chicken giblets (47.3% of samples) was detected. However, thermotolerant Campylobacter spp. were found in only 1.2% of the ready-to-eat poultry products. 相似文献
88.
The association between acyl-CoA synthetase (ACSL4) polymorphism and intramuscular fat content in (Landrace × Yorkshire) × Duroc pigs 总被引:1,自引:0,他引:1
Ruść A Sieczkowska H Krzęcio E Antosik K Zybert A Koćwin-Podsiadła M Kamiński S 《Meat science》2011,89(4):440-443
The aim of the study was to check whether different genotypes at acyl-CoA synthetase (ACSL4 locus, SNP G2645A) are associated with pork quality. 132 (Landrace × Yorkshire) × Duroc fatteners were genotyped by originally developed PCR-RFLP method. Upon the slaughter, the samples of longissimus lumborum muscle were taken from each carcass to determine the following parameters: content of water, protein and fat, pH (45 min, 24, 48, 96, and 144 h post mortem), electrical conductivity, drip loss, meat lightness, glycolytic potential, glycogen and lactate contents in meat. Among several associations observed, the highly significant (p<0.01) was found for intramuscular fat (IMF) content. Pigs with genotype GG revealed the highest content of IMF - 2.47%. 相似文献
89.
Beganović J Pavunc AL Gjuračić K Spoljarec M Sušković J Kos B 《Journal of food science》2011,76(2):M124-M129
Probiotic strain Lactobacillus plantarum L4 and strain Leuconostoc mesenteroides LMG 7954 were applied for the controlled fermentation of cabbage heads. The parameters of the controlled and spontaneous fermentations, including antimicrobial effect of cabbage brines obtained at the end of both fermentations, were monitored. To check out the influence of starter culture strains, 10 randomly chosen lactic acid bacteria, isolated at the end of controlled cabbage heads fermentation were identified by API 50 CHL test, and the presence of the probiotic culture was confirmed by Pulsed Field Gel Electrophoresis. The starter cultures applied for cabbage heads fermentation allowed lowering of NaCl concentrations from 4.0% to 2.5% (w/v), considerably accelerated fermentation process by 14 d, and improved the product quality. The produced sauerkraut heads are considered probiotic product as viable probiotic cells count in final product was higher than 10(6) colony-forming units (CFU) per gram of product. PRACTICAL APPLICATION: The results of this research could be applied in the production of fermented cabbage heads with added functional (probiotic) value and with lower NaCl concentration with expected shortened fermentation time. This could not only be of economic but also of ecological importance. 相似文献
90.
Mladen Brnčić Tomislav Bosiljkov Marko Ukrainczyk Branko Tripalo Suzana Rimac Brnčić Sven Karlović Damir Karlović Damir Ježek Dražen Vikić Topić 《Food and Bioprocess Technology》2011,4(7):1296-1306
Production of extrudates from cereals is an often-used technological process in today’s world food industry. Extrudates from corn flour produced using the twin-screw extrusion process and enriched with whey protein concentrate represent high-quality source of proteins and fats. Whey protein concentrate (WPC) as a valuable source of proteins and minerals is one of the highest-quality components for possible extrudate enrichment. In this paper, the influence of various WPC addition and some extrusion process parameters such as feed moisture content ( QtextHtext2 textO Q_{{{text{H}}_{text{2}} {text{O}}}} ) on physicochemical properties of directly expanded corn flour extrudates manufactured in twin-screw co-rotating extruder was investigated. Whey protein concentrate was added in the following ratios 7.5%, 15% and 22.5% and water in 10.08, 12.18 and 14.28 L/h. Final composition of products is determined with measuring of protein, fat and water shares, water absorption index (WAI) and water solubility index (WSI). With added WPC and with increase of water volume flow, there was a significant rise in total protein, fat and water content in final products, as well as lowering of WSI and rising of WAI indexes. The statistical analysis of the obtained data shows that the lowest WSI and the highest WAI had samples with the largest share of WPC (22.5%) and water volume flow of 14.28 L/h. Colour is measured for each sample, and results were represented with hue angle (H), chroma (C) and lightness (L) values. Process parameters, WPC and QtextHtext2 textO Q_{{{text{H}}_{text{2}} {text{O}}}} influence the increase of saturation of C and lightness of L colour value, while H value stays unchanged. Mean value of H was 90.14 ± 1.06, which corresponds to dominance of yellow colour of samples. 相似文献