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排序方式: 共有402条查询结果,搜索用时 203 毫秒
191.
192.
H Offner M Vainiene D P Gold B Celnik R Wang G A Hashim A A Vandenbark 《Journal of immunology (Baltimore, Md. : 1950)》1992,148(6):1706-1711
In Lewis rats, immunization with myelin basic protein induces two distinct encephalitogenic T cell populations, those responding to the immunodominant 72-89 epitope and those specific for a secondary epitope including residues 87-99. The 72-89 specific T cells were I-A restricted and preferentially expressed V beta 8.2 in their TCR. To determine the fine specificity, MHC restriction, and TCR V beta gene use in T cells reactive to the secondary epitope, we characterized 23 T cell clones from the lymph nodes (LN) and spinal cords (SC) of rats immunized with either whole basic protein or synthetic peptides S85-99 and S87-99 that were found to be functionally similar. The S85-99/S87-99 specific clones from LN and SC were all encephalitogenic despite differences in recognition of intact basic protein and class II MHC restriction. Unlike LN clones that overexpressed V beta 8 (46%+) and V beta 6 (31%+), however, SC clones were strongly biased (86%+) in their expression of V beta 6. This V gene bias raised the possibility of TCR peptide therapy using V beta 6 peptides. The V beta 6 sequence was similar to V beta 8.2 in the CDR2 region, and the corresponding peptides from this region were found to be cross-reactive in vivo. Moreover, both peptides were effective in the treatment of EAE induced with either S85-99, biased in V beta 6+ and V beta 8+ T cells, or guinea pig basic protein, biased only in V beta 8+ T cells. These data demonstrate the presence of common immunogenic epitopes among subsets of TCR V region gene families that possess important regulatory activity on effector T cell function. 相似文献
193.
Alpha-toxin binding to acetylcholine receptor alpha 179-191 peptides: intrinsic fluorescence studies 总被引:1,自引:0,他引:1
Interactions between two alpha-toxins and the synthetic peptides alpha 179-191 from both calf and human acetylcholine receptor alpha-subunit sequences have been studied by measurements of quenching of intrinsic fluorescence after toxin addition. Dissociation constants of approx. 5 x 10(-8) M for binding of calf peptide by both alpha-cobratoxin and erabutoxin a have been estimated. The binding of alpha-cobratoxin to calf peptide, which leads to marked quenching of fluorescence intensity, is inhibited by a 10(4) molar excess of acetylcholine. The human alpha 179-191 peptide binds to alpha-cobratoxin, but not, under comparable conditions, to erabutoxin a. 相似文献
194.
Samson D. O. Jafri M. Z. Mat Shukri A. Hashim R. Sulaiman O. Aziz M. Z. A. Yusof M. F. M. 《Radiation and environmental biophysics》2020,59(3):483-501
Radiation and Environmental Biophysics - For the first time, Rhizophora spp. (Rh. spp.) particleboard phantoms were developed using defatted soy flour (DSF) and soy protein isolate (SPI) modified... 相似文献
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Summary A new species ofTrichodorus is described from the rhizosphere of vegetables (Lycopersicon esculentum Mill. andPhaseolus vulgaris L.) in Jordan and from the rhizosphere of grape-vine (Vitis sp.) in Iran.The females are characterized by the shape of the sclerotized thickenings at the vulva. The males are characterized by the shorter body, onchiostyle and spicules and by the shape of the spicules. ac]19830124 相似文献
198.
Rangarajan M Aduse-Opoku J Paramonov N Hashim A Bostanci N Fraser OP Tarelli E Curtis MA 《Journal of bacteriology》2008,190(8):2920-2932
We previously described a cell surface anionic polysaccharide (APS) in Porphyromonas gingivalis that is required for cell integrity and serum resistance. APS is a phosphorylated branched mannan that shares a common epitope with posttranslational additions to some of the Arg-gingipains. This study aimed to determine the mechanism of anchoring of APS to the surface of P. gingivalis. APS was purified on concanavalin A affinity columns to minimize the loss of the anchoring system that occurred during chemical extraction. (1)H nuclear magnetic resonance spectroscopy of the lectin-purified APS confirmed the previous structure but also revealed additional signals that suggested the presence of a lipid A. This was confirmed by fatty acid analysis of the APS and matrix-assisted laser desorption ionization-time of flight mass spectrometry of the lipid A released by treatment with sodium acetate buffer (pH 4.5). Hence, P. gingivalis synthesizes two distinct lipopolysaccharide (LPS) macromolecules containing different glycan repeating units: O-LPS (with O-antigen tetrasaccharide repeating units) and A-LPS (with APS repeating units). Nonphosphorylated penta-acylated and nonphosphorylated tetra-acylated species were detected in lipid A from P. gingivalis total LPS and in lipid A from A-LPS. These lipid A species were unique to lipid A derived from A-LPS. Biological assays demonstrated a reduced proinflammatory activity of A-LPS compared to that of total LPS. Inactivation of a putative O-antigen ligase (waaL) at PG1051, which is required for the final step of LPS biosynthesis, abolished the linkage of both the O antigen and APS to the lipid A core of O-LPS and A-LPS, respectively, suggesting that WaaL in P. gingivalis has dual specificity for both O-antigen and APS repeating units. 相似文献
199.
Dethoff EA Hansen AL Musselman C Watt ED Andricioaei I Al-Hashimi HM 《Biophysical journal》2008,95(8):3906-3915
The HIV-1 transactivation response element (TAR) RNA binds a variety of proteins and is a target for developing anti-HIV therapies. TAR has two primary binding sites: a UCU bulge and a CUGGGA apical loop. We used NMR residual dipolar couplings, carbon spin relaxation (R1 and R2), and relaxation dispersion (R1ρ) in conjunction with molecular dynamics and mutagenesis to characterize the dynamics of the TAR apical loop and investigate previously proposed long-range interactions with the distant bulge. Replacement of the wild-type apical loop with a UUCG loop did not significantly affect the structural dynamics at the bulge, indicating that the apical loop and the bulge act largely as independent dynamical recognition centers. The apical loop undergoes complex dynamics at multiple timescales that are likely important for adaptive recognition: U31 and G33 undergo limited motions, G32 is highly flexible at picosecond-nanosecond timescales, and G34 and C30 form a dynamic Watson-Crick basepair in which G34 and A35 undergo a slow (∼30 μs) likely concerted looping in and out motion, with A35 also undergoing large amplitude motions at picosecond-nanosecond timescales. Our study highlights the power of combining NMR, molecular dynamics, and mutagenesis in characterizing RNA dynamics. 相似文献
200.
Samwel Gesase Roly D. Gosling Ramadhan Hashim Rosalynn Ord Inbarani Naidoo Rashid Madebe Jacklin F. Mosha Angel Joho Victor Mandia Hedwiga Mrema Ephraim Mapunda Zacharia Savael Martha Lemnge Frank W. Mosha Brian Greenwood Cally Roper Daniel Chandramohan 《PloS one》2009,4(2)