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排序方式: 共有267条查询结果,搜索用时 31 毫秒
31.
Marika E. Nissilä Hanne P. TähtiJukka A. Rintala Jaakko A. Puhakka 《International Journal of Hydrogen Energy》2011,36(2):1482-1490
Elevated temperatures (52, 60 and 65 °C) were used to enrich hydrogen producers on cellulose from cow rumen fluid. Methanogens were inhibited with two different heat treatments. Hydrogen production was considerable at 60 °C with the highest H2 yield of 0.44 mol-H2 mol-hexose−1 (1.93 mol-H2 mol-hexose-degraded−1) as obtained without heat treatment and with acetate and ethanol as the main fermentation products. H2 production rates and yields were controlled by cellulose degradation that was at the highest 21%. The optimum temperature and pH for H2 production of the rumen fluid enrichment culture were 62 °C and 7.3, respectively. The enrichments at 52 and 60 °C contained mainly bacteria from Clostridia family. At 52 °C, the bacterial diversity was larger and was not affected by heat treatments. Bacterial diversity at 60 °C remained similar between heat treatments, but decreased during enrichment. At 60 °C, the dominant microorganism was Clostridium stercorarium subsp. leptospartum. 相似文献
32.
Scope: Structural‐based recognition of foreign molecules is essential for activation of dendritic cells (DCs) that play a key role in regulation of gut mucosal immunity. Orally ingested non‐starch polysaccharides (NSP) are ascribed many health‐promoting properties, but currently we lack insight into the impact of structure and size for their capacity to affect immune responses. Methods and results: This study addresses the importance of chemical structure, size, origin and presence of contaminants for the capacity of both dietary and non‐food NSP to modulate DC. Of 28 NSP products, β‐glucans of microbial and plant origin and the galactomannan guar gum were found to modulate the DC cytokine pattern induced by the Toll‐like receptor 4‐ligand LPS giving rise to reduced IL‐12p70 and increased IL‐10 levels, whereas IL‐6 production was unaffected. A large proportion of the tested NSP were able to down‐regulate LPS‐induced IL‐12p70 production. The most potent NSP induced up‐regulation of CD86 on DC independently of LPS stimulation. Cereal‐based β‐glucans showed less potency than β‐glucans of microbial origin, but proper molecular weight composition and preparation may improve effectiveness. Conclusions: Collectively, this comparative study revealed that some plant‐derived NSP besides those of microbial origin exert modulation of the DC phenotype, with the exact structure being important for the activity. 相似文献
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Torben Leth Hanne Boskov Hansen Flemming Boisen 《European Food Research and Technology》2006,223(1):39-43
A survey for irradiation of 106 herbal food supplements was carried out in Denmark in 2003. The results from three methods, two screening methods and a specific method, were compared: Direct epifluorescent filter technique/aerobic plate count (DEFT/APC), photostimulated luminescence (PSL) and thermoluminescence (TL) standardised by Comité Européen de Normalisation (CEN). Forty samples screened positive with the DEFT/APC method. However, the TL method could only confirm irradiation of 15 samples, 11 samples wholly irradiated and 4 samples with a minor irradiated ingredient. Thus, the DEFT/APC method gave a large number of false positive results, although the number of false negative results probably was very low. Only 7 of the 15 confirmed irradiated samples screened positive with the PSL screening method, the samples with low photon counts escaping detection. For 10% of the samples also the TL method was lacking in sensitivity, as not enough minerals could be isolated to get a signal over the minimum detection level. For such clean herbal food supplements no suitable method exists at all among the CEN standardised methods for irradiation detection. 相似文献
35.
Henrik Pilegaard Flemming Nielson Hanne Riis Nielson 《Electronic Notes in Theoretical Computer Science》2007,175(1):57
In the context of process algebras it is customary to define semantics in the form of a reaction relation supported by a structural congruence relation. Recently process algebras have grown more expressive in order to meet the modelling demands of fields as diverse as business modelling and systems biology. This leads to combining various features, such as general choice and parallelism that were previously studied separately, and it often becomes difficult to define the reaction semantics. We present a general approach based on active evaluation contexts that allows the reaction semantics to be easily constructed. 相似文献
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37.
Jeppe Rass‐Hansen Hanne Falsig Betina Jørgensen Claus H Christensen 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2007,82(4):329-333
Increasing amounts of bioethanol are being produced from fermentation of biomass, mainly to counteract the continuing depletion of fossil resources and the consequential escalation of oil prices. Today, bioethanol is mainly utilized as a fuel or fuel additive in motor vehicles, but it could also be used as a versatile feedstock in the chemical industry. Currently the production of carbon‐containing commodity chemicals is dependent on fossil resources, and more than 95% of these chemicals are produced from non‐renewable carbon resources. The question is: what will be the optimal use of bioethanol in a longer perspective? Copyright © 2007 Society of Chemical Industry 相似文献
38.
Rasmussen SE Frederiksen H Struntze Krogholm K Poulsen L 《Molecular nutrition & food research》2005,49(2):159-174
The French have one of the lowest incidences of coronary heart disease in the Western world despite a diet with a relatively high fat content. This phenomenon that has puzzled researchers worldwide for more than a decade is known as the 'French paradox' and has been linked to the high consumption of red wine in France. Red wine is rich in the complex polyphenols, the proanthocyanidins, and these compounds have recently attracted attention as potential cardiac-protective compounds. The present review summarizes the literature on proanthocyanidins with focus on their chemical structure, the occurrence, the daily intake from foods, the bioavailability and metabolism, and the evidence for a protective effect against cardiovascular diseases. 相似文献
39.
In order to investigate a possible relationship between integrin degradation and water-holding capacity (WHC), integrin was quantified using western blot, and water mobility and distribution was measured by proton NMR T(2) relaxometry at 24h postmortem in pork (n=30) with a large variation in WHC (drip loss varying from 2.8% to 11.3%). Regression analyses revealed correlation coefficients of r=-0.32 (P=0.08) and r=0.40 (P=0.03) for the correlations between the content of integrin determined by western blot analysis and WHC determined as either drip loss or by NMR, respectively. Water mobility and distribution was also measured in 18 meat samples upon 7 days of aging, which revealed a correlation (r=0.54) between integrin content determined by western blot analysis 24h postmortem and the mobility of the myofibrillar water (T(21) relaxation time) at day 7. In contrast, no correlation could be established between integrin content 24h postmortem and WHC at day 7 determined by NMR as the amount of extramyofibrillar water (T(22) population) (r=-0.01). In conclusion, both visualisation by CLSM and quantification of integrin by western blot analyses of suggested that a strong link between integrin degradation and WHC in pork is questionable, whereas integrin degradation seems to have impact on the succeeding development in the mobility of the myofibrillar water. 相似文献
40.
Mette Schmedes Asker Daniel Brejnrod Eli Kristin Aadland Pia Kiilerich Karsten Kristiansen Hlne Jacques Charles Lavigne Ingvild Eide Graff
yvin Eng Asle Holthe Gunnar Mellgren Jette Feveile Young Ulrik Krmer Sundekilde Bjrn Liaset Hanne Christine Bertram 《Molecular nutrition & food research》2019,63(1)