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61.
Alternaria alternata is a common fungal parasite on fruits and other plants and produces a number of mycotoxins, including alternariol (3,7,9-trihydroxy-1-methyl-6H-dibenzo [b,d]pyran-6-one), alternariol monomethyl ether (3,7-dihydroxy-9-methoxy-1-methyl-6H-dibenzo[b,d]pyran-6-one), and the mutagen altertoxin I {[1S-(1α,12aβ,12bα)] 1,2,11,12,12a, 12b-hexahydro-1,4,9,12a-tetrahydroxy-3,10-perylenedione}.
Alternariol and alternariol monomethyl ether have previously been detected in some samples of fruit beverages. Stability studies
of these toxins as well as altertoxin I added to fruit juices and wine (10–100 ng/mL) were carried out. To include altertoxin
I in the analysis, cleanup with a polymer-based Varian Abselut solid phase extraction column was used, as recoveries from
C-18 columns were low. The stabilities of alternariol and alternariol monomethyl ether in a low acid apple juice containing
no declared vitamin C were compared with those in the same juice containing added vitamin C (60 mg/175 ml); there were no
apparent losses at room temperature over 20 days or at 80°C after 20 min. in either juice. Altertoxin I was moderately stable
in pH 3 buffer (75% remaining after a two week period). Furthermore, altertoxin I was stable or moderately stable in three
brands of apple juice tested over 1–27 day periods and in a sample of red grape juice over 7 days. It is concluded that altertoxin
I is sufficiently stable to be found in fruit juices and should be included in methods for alternariol and alternariol monomethyl
ether. 相似文献
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Human introduction or natural dispersion? Atlantic Ocean occurrence of the Indo‐Pacific whitetip reef shark Triaenodon obesus
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H. Bornatowski R. Loose C. L. S. Sampaio O. B. F. Gadig A. Carvalho‐Filho R. R. Domingues 《Journal of fish biology》2018,92(2):537-542
Occurrence of multiple whitetip reef sharks Triaenodon obesus in the Atlantic Ocean is reported for the first time from near a sunken ferry off the Paraná coast in south‐eastern Brazil. This occurrence is hypothesized to have been caused by either a human introduction or a remarkably long oceanic displacement. 相似文献
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Luiz Fernando Freire Royes Patrícia Gabbi Leandro Rodrigo Ribeiro Iuri Domingues Della-Pace Fernanda Silva Rodrigues Ana Paula de Oliveira Ferreira Mauro Eduardo Porto da Silveira Junior Luís Roberto Hart da Silva Alan Barroso Araújo Grisólia Danielle Valente Braga Fernando Dobrachinski Anderson Manoel Herculano Oliveira da Silva Félix Alexandre Antunes Soares Sara Marchesan Ana Flavia Furian Mauro Schneider Oliveira Michele Rechia Fighera 《Amino acids》2016,48(6):1373-1389
67.
Continuous ethanol fermentation of lactose by a recombinant flocculating Saccharomyces cerevisiae strain. 总被引:2,自引:0,他引:2
Alcohol fermentation of lactose was investigated using a recombinant flocculating Saccharomyces cerevisiae, expressing the LAC4 (coding for beta-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus. Data on yeast fermentation and growth on a medium containing lactose as the sole carbon source are presented. In the range of studied lactose concentrations, total lactose consumption was observed with a conversion yield of ethanol close to the expected theoretical value. For the continuously operating bioreactor, an ethanol productivity of 11 g L(-1) h(-1) (corresponding to a feed lactose concentration of 50 g L(-1) and a dilution rate of 0.55 h(-1)) was obtained, which is 7 times larger than the continuous conventional systems. The system stability was confirmed by keeping it in operation for 6 months. 相似文献
68.
A flocculent Saccharomyces cerevisiae strain with the ability to express both the LAC4 (coding for β-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus was constructed. This recombinant strain is not only able to grow on lactose, but it can also ferment this substrate. To
our knowledge this is the first time that a recombinant S. cervisiae has been found to ferment lactose in a way comparable to that of the existing lactose-fermenting yeast strains. Moreover,
the flocculating capacity of the strain used in this work gives the process several advantages. On the one hand, it allows
for operation in a continuous mode at high cell concentration, thus increasing the system's overall productivity; on the other
hand, the biomass concentration in the effluent is reduced, thus decreasing product separation/purification costs.
Received: 2 October 1998 / Received revision: 15 January 1999 / Accepted: 17 January 1999 相似文献
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Karin A. Riske Cleyton C. Domingues Bruna R. Casadei Bruno Mattei Amanda C. Caritá Rafael B. Lira Paulo S. C Preté Eneida de Paula 《Biophysical reviews》2017,9(5):649-667
Detergents are amphiphilic molecules widely used to solubilize biological membranes and/or extract their components. Nevertheless, because of the complex composition of biomembranes, their solubilization by detergents has not been systematically studied. In this review, we address the solubilization of erythrocytes, which provide a relatively simple, robust and easy to handle biomembrane, and of biomimetic models, to stress the role of the lipid composition on the solubilization process. First, results of a systematic study on the solubilization of human erythrocyte membranes by different series of non-ionic (Triton, CxEy, Brij, Renex, Tween), anionic (bile salts) and zwitterionic (ASB, CHAPS) detergents are shown. Such quantitative approach allowed us to propose Re sat—the effective detergent/lipid molar ratio in the membrane for the onset of hemolysis as a new parameter to classify the solubilization efficiency of detergents. Second, detergent-resistant membranes (DRMs) obtained as a result of the partial solubilization of erythrocytes by TX-100, C12E8 and Brij detergents are examined. DRMs were characterized by their cholesterol, sphingolipid and specific proteins content, as well as lipid packing. Finally, lipid bilayers of tuned lipid composition forming liposomes were used to investigate the solubilization process of membranes of different compositions/phases induced by Triton X-100. Optical microscopy of giant unilamellar vesicles revealed that pure phospholipid membranes are fully solubilized, whereas the presence of cholesterol renders the mixture partially or even fully insoluble, depending on the composition. Additionally, Triton X-100 induced phase separation in raft-like mixtures, and selective solubilization of the fluid phase only. 相似文献