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101.
Cross-linking of T3 (CD3) with T4 (CD4) enhances the proliferation of resting T lymphocytes 总被引:13,自引:0,他引:13
P Anderson M L Blue C Morimoto S F Schlossman 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(3):678-682
Monoclonal antibodies reactive with defined T lymphocyte surface antigens were covalently coupled to protein A-Sepharose beads using the bifunctional imidoester, dimethyl pimelimidate. Sepharose-immobilized antibody reactive with T3 induced the proliferation of resting T lymphocytes in the presence of either recombinant interleukin 2 or phorbol myristate acetate. When monoclonal antibodies reactive with T3 and T4 were coupled to the same Sepharose bead (hereafter designated Sepharose (T3:T4)), proliferation was enhanced an average of three-fold. Similarly prepared Sepharose beads coupled to anti-T3 and anti-T8 also enhanced proliferation over that observed with anti-T3 alone. Sepharose (T3:T4) similarly increased the proliferation of T4+ lymphocytes and a T4+ clone but failed to enhance the proliferation of T8+ lymphocytes. The increased proliferation of T4+ lymphocytes resulted from a preferential activation of the T4+2H4- helper population over the T4+2H4+ suppressor-inducer population. The enhanced proliferation induced by Sepharose (T3:T4) could be completely inhibited by soluble anti-T4. These results suggest that perturbation of T3 may be a minimal signal for T cell activation and that the assembly of a multimeric complex including T3 and T4 may be required for optimal T cell activation. 相似文献
102.
Phosphorylation of CD4 and CD8 molecules following T cell triggering 总被引:14,自引:0,他引:14
M L Blue D A Hafler K A Craig H Levine S F Schlossman 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(12):3949-3954
CD4 and CD8 molecules have been implicated in the regulation of T cell activation. In the present study, CD4 and CD8 were modified by increased phosphorylation when T cell clones or T cells were either exposed to phorbol-12-myristate- 13-acetate or were triggered via the CD3-T cell receptor complex. Activation of T cells through the CD2 sheep erythrocyte binding protein, using anti-T11(2) and -T11(3) antibodies, also resulted in CD4 and CD8 phosphorylation. These findings suggest that signals derived from two different receptor pathways can converge and result in similar molecular modifications of CD4 and CD8. Furthermore, phorbol myristate acetate treatment or activation via the CD2 pathway induced phosphorylation of the CD4 and CD8 molecules of thymocytes, suggesting that these molecules may be functional in thymus. Together, our findings indicate that CD4 and CD8 phosphorylation is a consequence of T cell triggering, and suggest that CD4 and CD8 phosphorylation may represent a molecular signaling mechanism among the CD3-T cell receptor complex, CD2, CD4, and CD8. 相似文献
103.
Norman L. Letvin Wayne R. Aldrich David A. Thorley-Lawson Stuart F. Schlossman Lee M. Nadler 《Cellular immunology》1984,84(1):163-170
It is shown that B-cell-specific surface antigens are conserved on lymphocytes from phylogenetically distant primate species. Characterization of the expression of those antigens on the surface of simian B lymphocytes has led to two observations with important implications for human B-cell physiology. First, lectin stimulation in vitro or antigen stimulation in situ in lymph nodes drives a population of human B lymphocytes to express the B2 but not the B1 antigen on its surface. Second, under pathologic circumstances, this activated B cell can be found in the peripheral blood of monkeys. Thus, the “B2 only” cell defines an activated B lymphocyte whose presence may provide useful diagnostic information concerning pathologic processes. 相似文献
104.
The early adaptive evolution of calmodulin 总被引:7,自引:0,他引:7
Baba ML; Goodman M; Berger-Cohn J; Demaille JG; Matsuda G 《Molecular biology and evolution》1984,1(6):442-455
Interaction between gene duplication and natural selection in molecular
evolution was investigated utilizing a phylogenetic tree constructed by the
parsimony procedure from amino acid sequences of 50 calmodulin- family
protein members. The 50 sequences, belonging to seven protein lineages
related by gene duplication (calmodulin itself, troponin-C, alkali and
regulatory light chains of myosin, parvalbumin, intestinal calcium-binding
protein, and glial S-100 phenylalanine-rich protein), came from a wide
range of eukaryotic taxa and yielded a denser tree (more branch points
within each lineage) than in earlier studies. Evidence obtained from the
reconstructed pattern of base substitutions and deletions in these
ancestral loci suggests that, during the early history of the family,
selection acted as a transforming force on expressed genes among the
duplicates to encode molecular sites with new or modified functions. In
later stages of descent, however, selection was a conserving force that
preserved the structures of many coadapted functional sites. Each branch of
the family was found to have a unique average tempo of evolutionary change,
apparently regulated through functional constraints. Proteins whose
functions dictate multiple interaction with several other macromolecules
evolved more slowly than those which display fewer protein-protein and
protein-ion interactions, e.g., calmodulin and next troponin-C evolved at
the slowest average rates, whereas parvalbumin evolved at the fastest. The
history of all lineages, however, appears to be characterized by rapid
rates of evolutionary change in earlier periods, followed by slower rates
in more recent periods. A particularly sharp contrast between such fast and
slow rates is found in the evolution of calmodulin, whose rate of change in
earlier eukaryotes was manyfold faster than the average rate over the past
1 billion years. In fact, the amino acid replacements in the nascent
calmodulin lineage occurred at residue positions that in extant metazoans
are largely invariable, lending further support to the Darwinian hypothesis
that natural selection is both a creative and a conserving force in
molecular evolution.
相似文献
105.
E L Reinherz A J Strelkauskas C O'Brien S F Schlossman 《Journal of immunology (Baltimore, Md. : 1950)》1979,123(1):83-86
Prior work has demonstrated the existence of distinct human peripheral blood T cell subsets by utilizing heterologous as well as autoimmune antisera. In the present study, the relationship between the TH2+ and JRA+ T cell subsets was examined. T cells were purified with Sephadex G-200 anti-F(ab)2' affinity chromatography and E-rosetting technique, and subsequently fractionated into TH2+ and TH2- subsets by utilizing indirect immunofluorescence on FACS. Approximately 40 to 45% of the TH2- subset was shown to be JRA+, whereas less than 5% of the TH2+ subset was JRA+. In reciprocal studies, T cells were fractionated into JRA+ and JRA- subsets and reacted with heterologous antisera with anti-TH2+ specificity and indirect immunofluorescence. FACS analysis demonstrated that the JRA+ population contained no TH2+ T cells. In contrast, the JRA- population contained TH2+ T cells and accounted for the entire TH2+ subset found in the unfractionated T cell population. Functional studies showed that the TH2+ subset, and not the JRA+ subset, contain the effector population for cell-mediated lympholysis. It is concluded that the TH2+ and JRA+ T cell subsets define distinct and different T cell populations in man. 相似文献
106.
Natural killer-like activity mediated by activated T lymphocytes 总被引:1,自引:0,他引:1
Diverse types of lymphocytes mediate in vitro cytotoxic activity. In addition to CTLs (cytotoxic T lymphocytes) and NK (natural killer) cells which differ in their activation requirements, target specificities, and lytic mechanisms, a natural killer-like activity of activated cells (A-NK) has recently been described. The data presented here suggest that an activated T lymphocyte can mediate A-NK activity. A-NK activity can be separated from resting NK activity by its requirement for activation and an effector phenotype (T12+,Ia+,Mol-) which includes the presence of the T12 and Ia antigens and the absence of the Mol antigen. In contrast, resting NK activity is mediated by T12-,Ia-,Mol+ cells. Cells that mediate A-NK activity can be differentiated from CTLs by their differing kinetics of activation and susceptibility to inhibition by monoclonal antibodies. An additional distinguishing feature is the fact that A-NK cells are predominantly Ia+ and are derived from either the T4+ or T8+ T-cell subsets whereas CTLs generated under similar conditions are predominantly T8+,T4-,Ia-. The in vivo relevance of this newly defined T-cell cytolytic activity remains to be defined. 相似文献
107.
Immune response gene control of antibody specificity 总被引:1,自引:0,他引:1
The expression of the histocompatibility-linked PLL Ir gene was investigated in guinea pig B cells. Strain 2 and F1 (2 × 13) guinea pigs, immunized with the αDnp-Lys9, produce both T cells and antibody which are equally discriminatory for αDnp-Lys9. In contrast strain 13 (PLL Ir gene negative) guinea pigs immunized with αDnp-Lys9 do not develop specific T-cell responses and the antibody produced while restricted in heterogeneity cannot differentiate the immunizing antigen from Dnp-OH. However, if in a F1 (2 × 13) environment, PLL Ir gene-negative B cells are provided with F1 (2 × 13) T cells they express the ability to make antibody as specific and discriminatory as the antibody produced by PLL Ir gene-positive B cells. These findings strongly suggest that in the guinea pigs the PLL Ir gene defect is localized to the T cells and that the repertoire of specificity of B cells is similar if not identical in both responder and nonresponder animals. In addition these observations support the notion that the cellular locus for the PLL Ir gene expression in the guinea pigs is limited to T cells and not to macrophages and B lymphocytes. 相似文献
108.
The restriction enzyme TaqI digests 0.2% of the genomic DNA from the
grasshopper Caledia captiva to a family of sequences 168 bp in length
(length of consensus sequence). The sequence variation of this "Taq family"
of repeat units was examined among four races from C. captiva to assay the
pattern of evolution within this highly repeated DNA. The Taq-family
repeats are located in C-banded heterochromatin on at least one member of
each homologous pair of chromosomes; the locations range from centromeric
to telomeric. Thirty-nine cloned repeats isolated from two population 1A
individuals along with 11 clones from seven populations taken from three of
the races demonstrated sequence variation at 72 positions. Pairwise
comparisons of the cloned repeats, both within an individual and between
different races, indicate that levels of intraspecific divergence, as
measured by reproductive incompatibility, do not correlate with sequence
divergence among the 168-bp repeats. A number of subsequences within the
repeat remain unchanged among all 50 clones; the longest of these is 18 bp.
That the same 18-bp subsequence is present in all clones examined is a
finding that departs significantly (P less than 0.01) from what would be
expected to occur at random. Two other cloned repeats, from a
reproductively isolated race of C. captiva, have sequences that show 56%
identity with this 18-bp conserved region. An analysis showed that the
frequency of occurrence of an RsaI recognition site within the 168- bp
repeat in the entire Taq family agreed with that found in the cloned
sequences. These data, along with a partial sequence for the entire Taq
family obtained by sequencing uncloned repeats, suggest that the consensus
sequence from the cloned copies is representative of this highly repeated
family and is not a biased sample resulting from the cloning procedure. The
18-bp conserved sequence is part of a 42-bp sequence that possesses dyad
symmetry typical of protein-binding sites. We speculate that this may be
significant in the evolution of the Taq family of sequences.
相似文献
109.
Morimoto S Kanno Y Tanaka Y Tokano Y Hashimoto H Jacquot S Morimoto C Schlossman SF Yagita H Okumura K Kobata T 《Journal of immunology (Baltimore, Md. : 1950)》2000,164(8):4097-4104
CD134 is a member of the TNFR family expressed on activated T cells, whose ligand, CD134L, is found preferentially on activated B cells. We have previously reported that the CD70/CD27 interaction may be more important in the induction of plasma cell differentiation after the expansion phase induced by the CD154/CD40 interaction has occurred. When CD134-transfected cells were added to PBMCs stimulated with pokeweed mitogen, IgG production was enhanced in a dose-dependent fashion. Addition of CD134-transfected cells to B cells stimulated with Staphylococcus aureus Cowan I strain/IL-2 resulted in little if any enhancement of B cell IgG production and proliferation. We found that while CD134-transfected cells induced no IgG production by themselves, it greatly enhanced IgG production in the presence of CD40 stimulation or T cell cytokines such as IL-4 and IL-10. The addition of CD134-transfected cells showed only a slight increase in the number of plasma cells compared with that in the culture without them, indicating that an increased Ig production rate per cell is responsible for the observed enhancing effect of CD134L engagement rather than increase in plasma cell generation. These results strongly suggest different and sequential roles of the TNF/TNFR family molecules in human T cell-dependent B cell responses through cell-cell contacts and the cytokine network. 相似文献
110.
The differentiation and function of human T lymphocytes 总被引:2,自引:0,他引:2