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排序方式: 共有652条查询结果,搜索用时 31 毫秒
91.
Biotransformation of 2,4,6-Trinitrotoluene with Phanerochaete chrysosporium in Agitated Cultures at pH 4.5
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Jalal Hawari Annamaria Halasz Sylvie Beaudet Louise Paquet Guy Ampleman Sonia Thiboutot 《Applied microbiology》1999,65(7):2977-2986
The biotransformation of 2,4,6-trinitrotoluene (TNT) (175 μM) by Phanerochaete chrysosporium with molasses and citric acid at pH 4.5 was studied. In less than 2 weeks, TNT disappeared completely, but mineralization (liberated 14CO2) did not exceed 1%. A time study revealed the presence of several intermediates, marked by the initial formation of two monohydroxylaminodinitrotoluenes (2- and 4-HADNT) followed by their successive transformation to several other products, including monoaminodinitrotoluenes (ADNT). A group of nine acylated intermediates were also detected. They included 2-N-acetylamido-4,6-dinitrotoluene and its p isomer, 2-formylamido-4,6-dinitrotoluene and its p isomer (as acylated ADNT), 4-N-acetylamino-2-amino-6-nitrotoluene and 4-N-formylamido-2-amino-6-nitrotoluene (as acetylated DANT), 4-N-acetylhydroxy-2,6-dinitrotoluene and 4-N-acetoxy-2,6-dinitrotoluene (as acetylated HADNT), and finally 4-N-acetylamido-2-hydroxylamino-6-nitrotoluene. Furthermore, a fraction of HADNTs were found to rearrange to their corresponding phenolamines (Bamberger rearrangement), while another group dimerized to azoxytoluenes which in turn transformed to azo compounds and eventually to the corresponding hydrazo derivatives. After 30 days, all of these metabolites, except traces of 4-ADNT and the hydrazo derivatives, disappeared, but mineralization did not exceed 10% even after the incubation period was increased to 120 days. The biotransformation of TNT was accompanied by the appearance of manganese peroxidase (MnP) and lignin-dependent peroxidase (LiP) activities. MnP activity was observed almost immediately after TNT disappearance, which was the period marked by the appearance of the initial metabolites (HADNT and ADNT), whereas the LiP activity was observed after 8 days of incubation, corresponding to the appearance of the acyl derivatives. Both MnP and LiP activities reached their maximum levels (100 and 10 U/liter, respectively) within 10 to 15 days after inoculation. 相似文献
92.
Transcription originating in the long terminal repeats of the endogenous mouse mammary tumor virus MTV-3 is activated in Stat5a-null mice and picks Up hitchhiking exons.
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93.
Perturbation of maize rhizosphere microflora following seed bacterization with Burkholderia cepacia MCI 7 总被引:3,自引:0,他引:3
Carlo Nacamulli Annamaria Bevivino Claudia Dalmastri Silvia Tabacchioni Luigi Chiarini 《FEMS microbiology ecology》1997,23(3):183-193
Introduction of a large quantity of exogenous microorganisms may disrupt a local ecosystem and affect the natural microflora. In this work we investigated the effects of the introduction of a plant growth promoting strain of Burkholderia cepacia into the rhizosphere of maize on both indigenous B. cepacia populations and microbial community structure of total culturable bacteria using the concept of r/K strategy. Moreover we studied the distribution of bacterial populations in the root system at various soil depths. Seed bacterization was used as application method. Root colonization of the introduced strain occurred mainly on roots close to the plant stem, whereas indigenous B. cepacia was recovered at higher amounts from the lower parts of root systems of mature plants. As far as total culturable bacteria are concerned, an almost uniform distribution in the root system of mature plants was observed. The release of the exogenous bacterial strain affected mainly the microbial populations of young growing plants rather than mature plants. Indeed it caused only short-term perturbations in the microbial community of maize rhizosphere. Colonization of maize roots by indigenous B. cepacia was not significantly affected by the presence of the exogenous strain. 相似文献
94.
Uric Acid Amplifies Aβ Amyloid Effects Involved in the Cognitive Dysfunction/Dementia: Evidences From an Experimental Model In Vitro
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95.
96.
Annamaria Cimini Michele d'Angelo Elisabetta Benedetti Barbara D'Angelo Giulio Laurenti Andrea Antonosante Loredana Cristiano Antonella Di Mambro Marcella Barbarino Vanessa Castelli Benedetta Cinque Maria Grazia Cifone Rodolfo Ippoliti Francesca Pentimalli Antonio Giordano 《Journal of cellular physiology》2017,232(2):312-322
97.
Oversulfated chondroitin sulfate is a contaminant in heparin associated with adverse clinical events
Guerrini M Beccati D Shriver Z Naggi A Viswanathan K Bisio A Capila I Lansing JC Guglieri S Fraser B Al-Hakim A Gunay NS Zhang Z Robinson L Buhse L Nasr M Woodcock J Langer R Venkataraman G Linhardt RJ Casu B Torri G Sasisekharan R 《Nature biotechnology》2008,26(6):669-675
Recently, certain lots of heparin have been associated with an acute, rapid onset of serious side effects indicative of an allergic-type reaction. To identify potential causes for this sudden rise in side effects, we examined lots of heparin that correlated with adverse events using orthogonal high-resolution analytical techniques. Through detailed structural analysis, the contaminant was found to contain a disaccharide repeat unit of glucuronic acid linked beta1-->3 to a beta-N-acetylgalactosamine. The disaccharide unit has an unusual sulfation pattern and is sulfated at the 2-O and 3-O positions of the glucuronic acid as well as at the 4-O and 6-O positions of the galactosamine. Given the nature of this contaminant, traditional screening tests cannot differentiate between affected and unaffected lots. Our analysis suggests effective screening methods that can be used to determine whether or not heparin lots contain the contaminant reported here. 相似文献
98.
Francesca Gherardi Sandro Bertolino Marco Bodon Sandra Casellato Simone Cianfanelli Marco Ferraguti Elisabetta Lori Graziella Mura Annamaria Nocita Nicoletta Riccardi Giampaolo Rossetti Emilia Rota Riccardo Scalera Sergio Zerunian Elena Tricarico 《Biological invasions》2008,10(4):435-454
The paper provides a list of the non-indigenous animal species occurring today in Italian inland waters. Xenodiversity was
found to amount to 112 species (64 invertebrates and 48 vertebrates), which contribute for about 2% to the inland-water fauna
in Italy. Northern and central regions are most affected, and Asia, North America, and the rest of Europe are the main donor
continents. The large majority of non-indigenous species entered Italy as a direct or indirect effect of human intervention.
A difference between invertebrates and vertebrates was found for their mode of arrival (unintentional for invertebrates and
intentional for vertebrates). Accidental transport, in association with both fish (for aquaculture or stock enhancement) and
crops, has been the main vector of invertebrate introductions, whereas vertebrates were mostly released for stocking purposes.
Overall stock enhancement (47.92%) and culture (37.5%) prevailed over the other pathways. Seventeen and 7 species of our list
are included among the 100 worst invasive species of Europe (DAISIE) and of the world (IUCN), respectively. For some (but
not all) non-indigenous species recorded in Italy the multilevel impact exerted on the recipient communities and ecosystems
is known, even if rarely quantified, but knowledge on their chronic impact is still missing. Additional research is needed
to provide criteria for prioritizing intervention against well established invaders and identify which new potential invader
should be targeted as “unwanted”. 相似文献
99.
Structural and mechanical properties of UV-photo-cross-linked poly(N-vinyl-2-pyrrolidone) hydrogels 总被引:1,自引:0,他引:1
D'Errico G De Lellis M Mangiapia G Tedeschi A Ortona O Fusco S Borzacchiello A Ambrosio L 《Biomacromolecules》2008,9(1):231-240
Biocompatible poly( N-vinyl-2-pyrrolidone) (PVP) hydrogels have been produced by UV irradiation of aqueous polymer mixtures, using a high-pressure mercury lamp. The resulting materials have been characterized by a combination of experimental techniques, including rheology, small-angle neutron scattering (SANS), electron paramagnetic resonance (EPR), and pulsed gradient spin-echo nuclear magnetic resonance (PGSE-NMR), to put in evidence the relationship between the microstructural properties and the macrofunctional behavior of the gels. Viscoelastic measurements showed that UV photo-cross-linked PVP hydrogels present a strong gel mechanical behavior and viscoelastic moduli values similar to those of biological gels. The average distance between the cross-linking points of the polymer network was estimated from the hydrogels elastic modulus. However, SANS measurements showed that the network microstructure is highly inhomogeneous, presenting polymer-rich regions more densely cross-linked, surrounded by a water-rich environment. EPR and PGSE-NMR data further support the existence of these water-rich domains. Inclusion of a third component, such as glycerol, in the PVP aqueous mixture to be irradiated has been also investigated. A small amount of glycerol (<3% w/w) can be added keeping satisfactory properties of the hydrogel, while higher amounts significantly affect the cross-linking process. 相似文献
100.
Within the red blood cell the hemoglobin molecule is subjected to modulation mechanisms, namely homo- and heterotropic interactions, which optimize its functional behavior to the specific physiological requirements. At the cellular level, these modulation mechanisms are utilized to perform a number of other functions that are not minor with respect to the basic function of oxygen transport. Here we report some key examples concerning: (i) the interaction of hemoglobin with band 3 and its influence on glucose metabolism; (ii) the role of the ligand-linked quaternary transition of hemoglobin in the control of "NO bioactivity" and of gas diffusion; (iii) the interaction of plasma membrane with the various oxidative derivatives of the hemoglobin molecule. 相似文献