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Controlling the near‐infrared transparency of costal cartilage by impregnation with clearing agents and magnetite nanoparticles
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Yulia Alexandrovskaya Kirill Sadovnikov Andrey Sharov Anna Sherstneva Evgeniy Evtushenko Alexander Omelchenko Mariya Obrezkova Valery Tuchin Valery Lunin Emil Sobol 《Journal of biophotonics》2018,11(2)
Penetration depth of near‐infrared laser radiation to costal cartilage is controlled by the tissue absorption and scattering, and it is the critical parameter to provide the relaxation of mechanical stress throughout the whole thickness of cartilage implant. To enhance the penetration for the laser radiation on 1.56 μm, the optical clearing solutions of glycerol and fructose of various concentrations are tested. The effective and reversible tissue clearance was achieved. However, the increasing absorption of radiation should be concerned: 5°C‐8°C increase of tissue temperature was detected. Laser parameters used for stress relaxation in cartilage should be optimized when applying optical clearing agents. To concentrate the absorption in the superficial tissue layers, magnetite nanoparticle (NP) dispersions with the mean size 95 ± 5 nm and concentration 3.9 ± 1.1 × 1011 particles/mL are applied. The significant increase in the tissue heating rate was observed along with the decrease in its transparency. Using NPs the respective laser power can be decreased, allowing us to obtain the working temperature locally with reduced thermal effect on the surrounding tissue. 相似文献
95.
Valery Akparov Vladimir Timofeev Ilyas Khaliullin Vytas Švedas Inna Kuranova 《Journal of biomolecular structure & dynamics》2018,36(4):956-965
Carboxypeptidase B (EC 3.4.17.2) (CPB) is commonly used in the industrial insulin production and as a template for drug design. However, its ability to discriminate substrates with hydrophobic, hydrophilic, and charged side chains is not well understood. We report structure of CPB complex with a transition state analog N-sulfamoyl-L-phenylalanine solved at 1.74Å. The study provided an insight into structural basis of CPB substrate specificity. Ligand binding is affected by structure-depended conformational changes of Asp255 in S1’-subsite, interactions with Asn144 and Arg145 in C-terminal binding subsite, and Glu270 in the catalytic center. Side chain of the non-specific substrate analog SPhe in comparison with that of specific substrate analog SArg (reported earlier) not only loses favorable electrostatic interactions and two hydrogen bonds with Asp255 and three fixed water molecules, but is forced to be in the unfavorable hydrophilic environment. Thus, Ser207, Gly253, Tyr248, and Asp255 residues play major role in the substrate recognition by S1’-subsite. 相似文献
96.
Valery Andrushchenko Zoya Leonenko David Cramb Hans van de Sande Hal Wieser 《Biopolymers》2002,61(4):243-260
The interaction of natural calf thymus DNA with Cr3+ ions was studied at room temperature by means of vibrational CD (VCD) and infrared absorption (ir) spectroscopy, and atomic force microscopy (AFM). Cr3+ ion binding mainly to N7 (G) and to phosphate groups was demonstrated. ψ‐Type VCD spectra resembling electronic CD (ECD) spectra, which appear during ψ‐type DNA condensation, were observed. These spectra are characterized mainly by an anomalous, severalfold increase of VCD intensity. Such anomalous VCD spectra were assigned to DNA condensation with formation of large and dense particles of a size comparable to the wavelength of the probing ir beam and possessing large‐scale helicity. Atomic force microscopy confirmed DNA condensation by Cr3+ ions and the formation of tight DNA particles responsible for the ψ‐type VCD spectra. Upon increasing the Cr3+ ion concentration the shape of the condensates changed from loose flower‐like structures to highly packed dense spheres. No DNA denaturation was seen even at the highest concentration of Cr3+ ions studied. The secondary structure of DNA remained in a B‐form before and after the condensation. VCD and ir as well as AFM proved to be an effective combination for investigating DNA condensation. In addition to the ability of VCD to determine DNA condensation, VCD and ir can in the same experiment provide unambiguous information about the secondary structure of DNA contained in the condensed particles. © 2002 Wiley Periodicals, Inc. Biopolymers 61: 243–260, 2002 相似文献
97.
Valery Kudryashov Hyunjin M. Kim Govindaswami Ragupathi Samuel J. Danishefsky Philip O. Livingston K. O. Lloyd 《Cancer immunology, immunotherapy : CII》1998,45(6):281-286
Many human carcinomas overexpress the Lewisy (Ley) blood-group epitope [Fucα1→2Galβ1→4 (Fucα1→3)GlcNAcβ1→3Gal-]. With a view to developing Ley based vaccines we have examined the immunogenicity of Ley-protein conjugates in mice. Ley pentasaccharide was synthesized as its allyl glycoside and coupled to keyhole limpet hemocyanin (KLH) by reductive amination
or by a novel method utilizing a maleido-derivitized alkyl carboxyhydrazide as a bridging group to 2-iminothiolane-derivitized
KLH. Ley oligosaccharide was also coupled to bovine serum albumin by reductive amination. Immunization of groups of mice with the
three conjugates, together with the immunological adjuvant QS21, showed that Ley oligosaccharide directly coupled to KLH was the most efficient conjugate for eliciting IgG and IgM antibody responses to
naturally occurring forms of Ley epitopes carried on mucins and glycolipids. These antibodies were also reactive with and cytotoxic to a human breast cancer
cell line expressing Ley (MCF-7). These experiments suggest that Ley-KLH antigen and QS21 adjuvant could be considered as an immunogenic therapeutic vaccine in carcinoma patients.
Received: 28 March 1997 / Accepted: 2 September 1997 相似文献
98.
Natalia V. Povarova Nadezda M. Markina Mikhail S. Baranov Nikolay A. Barinov Dmitry V. Klinov Valery B. Kozhemyako Konstantin A. Lukyanov 《Biochemical and biophysical research communications》2018,495(2):2066-2070
Silicateins, the spicule-forming proteins from marine demosponges capable to polymerize silica, are popular objects of biomineralization studies due to their ability to form particles varied in shape and composition under physiological conditions. Despite the occurrence of the many approaches to nanomaterial synthesis using silicateins, biochemical properties of this protein family are poorly characterized. The main reason for this is that tetraethyl orthosilicate (TEOS), the commonly used silica acid precursor, is almost insoluble in water and thus is poorly available for the protein. To solve this problem, we synthesized new water-soluble silica precursor, tetra(glycerol)orthosilicate (TGS), and characterized biochemical properties of the silicatein A1 from marine sponge Latrunculia oparinae. Compared to TEOS, TGS ensured much greater activity of silicatein and was less toxic for the mammalian cell culture. We evaluated optimum conditions for the enzyme - pH range, temperature and TGS concentration. We concluded that TGS is a useful silica acid precursor that can be used for silica particles synthesis and in vivo applications. 相似文献
99.
100.
LXA4, aspirin-triggered 15-epi-LXA4, and their analogs selectively downregulate PMN azurophilic degranulation 总被引:2,自引:0,他引:2
Gewirtz Andrew T.; Fokin Valery V.; Petasis Nicos A.; Serhan Charles N.; Madara James L. 《American journal of physiology. Cell physiology》1999,276(4):C988
The eicosanoid lipoxin A4(LXA4) is biosynthesized in vivoby cells present at inflammatory sites and appears to be an endogenous anti-inflammatory mediator. Further, in the presence of aspirin, the15-epimer of LXA4(15-epi-LXA4) is biosynthesizedand may mediate some of aspirin's desirable bioactions.LXA4,15-epi-LXA4, and their stableanalogs inhibit inflammation in established animal models, indicatingthat these compounds may be useful for treating inflammatory diseasestates. To investigate the cellular mechanisms by which these lipidmediators downregulate inflammation, we investigated whether theseeicosanoids could influence receptor-mediated degranulation of humanneutrophils, an event thought to play a major causative role in severalinflammatory disease states. LXA4,15-epi-LXA4, and their stableanalogs potently (IC50 < 1 nM)and selectively downregulated neutrophil release of azurophilic granulecontents but did not affect other neutrophil secretory functions. Thus the cellular basis of action of these natural off-switches to inflammation appears to involve downregulation of neutrophilazurophilic granule release. 相似文献