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61.
The interaction of CD28 and its ligands (CD80, CD86) on antigen presenting cells and that of TCR/CD3-MHC are required for T lymphocyte activation. To determine whether impaired lymphocyte proliferation associated with iron deficiency is due to reduced expression of these ligands, spleen cells obtained from eight to nine C57BL/6 mice/group of iron deficient (ID), iron replete (R), control (C), pair-fed (PF), and high iron (HI) mice were labeled with anti-CD80-fluorescein isothiocyante (FITC) and anti-CD86-FITC. Diets differed only in iron concentration: 5, 50, and 125 mg/kg for the ID, C, and HI, respectively. Mean levels of hemoglobin and liver iron stores of ID and R mice were less than 50% those of C mice (P < 0.005). In non-activated and concanavalin A-treated cultures, significant differences were observed among groups in the percentage of CD80 + cells: ID>R > C = PF = HI (P < 0.05). The same trend was observed for CD86 + cells (P > 0.05). Fluorescence intensity (FI) of either marker did not significantly change by iron status. In vitro iron chelation by deferoxamine (20, 200 microg/ml) for 1, 2, and 24 h increased FI of both markers on unactivated B and T cells (P < 0.05). However, it had no effect on FI of either marker of mitogen-treated cells presumably because the maximum levels are achieved by the mitogen. Lymphocyte proliferative responses to mitogens positively and significantly correlated with CD80 and CD86 FI (r = 0.41-0.59) but negatively correlated with the percentages of CD80 + cells (r = -0.48) (P < 0.05). Data suggest that impaired lymphocyte proliferation associated with iron deficiency is not due to reduced CD80 and CD86 expression. 相似文献
62.
In HIV-infected patients, large quantities of HIV are associated with follicular dendritic cells (FDCs) in lymphoid tissue. During antiretroviral therapy, most of this virus disappears after six months of treatment, suggesting that FDC-associated virus has little influence on the eventual outcome of long-term therapy. However, a recent theoretical study using a stochastic model for the interaction of HIV with FDCs indicated that some virus may be retained on FDCs for years, where it can potentially reignite infection if treatment is interrupted. In that study, an approximate expression was used to estimate the time an individual virion remains on FDCs during therapy. Here, we determine the conditions under which this approximation is valid, and we develop expressions for the time a virion spends in any bound state and for the effect of rebinding on retention. We find that rebinding, which is influenced by diffusion, may play a major role in retention of HIV on FDCs. We also consider the possibility that HIV is retained on B cells during therapy, which like FDCs also interact with HIV. We find that virus associated with B cells is unlikely to persist during therapy. 相似文献
63.
The aim of the study was to examine the effects of zinc supplementation on some hematological parameters. Sixty newborn male
broiler chicks were utilized in the study. Zinc (Zn) was added into drinking water at levels of 0, 125, 500, and 1000 mg/kg.
In the study, there was no significant difference between control and Zn-supplemented groups in erythrocyte count, hemoglobin
amount, hematocrit levels, total leukocyte count, and differential leukocyte % levels, but the α-naphthyl acetate esterase
ANAE(+) lymphocyte rate significantly (p<0.05) increased in the 125-ppm Zn-supplemented group compared with the control group. In conclusion, the data obtained may
be beneficial in demonstrating the effects of zinc on, at least, these parameters. 相似文献
64.
Yuan J Bae D Cantrell D Nel AE Rozengurt E 《Biochemical and biophysical research communications》2002,291(3):444-452
Protein kinase D (PKD/PKCmu immunoprecipitated from either COS-7 cells or Jurkat T lymphocytes transiently transfected with a constitutively active mutant of PKCtheta AE (PKCthetaAE) exhibited a marked increase in basal activity. In contrast, coexpression of constitutively active mutant of PKCzeta does not induce PKD activation in both types of cells. PKCthetaAE does not induce kinase activity in immunocomplexes of PKD kinase-deficient mutants PKDK618N or PKDD733A. PKD activation in response to PKCthetaAE signaling was completely prevented by treatment with the protein kinase C (PKC) inhibitors, GF I or Ro 31-8220, or by mutation of Ser-744 and Ser-748 to Ala in the kinase activation loop of PKD. Our results show that PKD is a downstream target of the theta isoform of PKC in both COS-7 cells and lymphocytes. The regulation of PKD by PKCtheta reveals a new pathway in the signaling network existing between multiple members of the PKC superfamily and PKD. 相似文献
65.
Measurement of CTL-induced cytotoxicity: The caspase 3 assay 总被引:2,自引:0,他引:2
Jerome KR Sloan DD Aubert M 《Apoptosis : an international journal on programmed cell death》2003,8(6):563-571
Cytotoxic T lymphocytes (CTL) are critical effector cells of the immune system. Measurement of target cell damage has historically been an important measure of CTL function. CTL kill their target cells predominantly by inducing programmed cell death, or apoptosis. The gold standard for CTL-mediated cytotoxicity has been the 51Cr release assay. However, measurement of target cell lysis by 51Cr release does not provide mechanistic information on the fate of target cells, especially at the single cell level. Given the recent advances in our understanding of programmed cell death, newer assays are required which evaluate the status of the apoptotic pathways in target cells. We have developed a flow cytometry-based assay for CTL-mediated cytotoxicity based on specific binding of antibody to activated caspase 3 in target cells. Our assay is convenient and more sensitive than the 51Cr release assay. The use of this assay should allow mechanistic studies of the intracellular events resulting from CTL attack. 相似文献
66.
The new world primate Aotus sp. has been recommended by the World Health Organization as a model for evaluation of malaria vaccine candidates, given its susceptibility to experimental infection with the human malaria parasites Plasmodium falciparum and P. vivax. The present study examined the in vitro proliferative response of peripheral blood mononuclear cells (PBMCs) isolated from Aotus monkeys, utilizing a wide range of mitogens. Results presented herein demonstrate that the in vitro proliferative response of PBMCs from the Aotus sp. is quite variable from monkey to monkey for each of the mitogens assessed. PBMCs from the Aotus monkey exhibited a delayed kinetic proliferative response and, particularly, a different sensitivity to proliferation in response to various concentrations of Phytohemagglutinin-P and favin lectins, the phorbol ester Phorbol myristate acetate and the calcium ionophore ionomycin. Altogether, our findings are consistent with the conclusion that the in vitro proliferative response of PBMCs from the Aotus differ in their activation requirements compared with PBMCs from humans. 相似文献
67.
García JJ del Carmen Sáez M De la Fuente M Ortega E 《Molecular and cellular biochemistry》2003,254(1-2):305-309
The capacity of noradrenaline (NA) and its end metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) to modulate the chemotaxis of lymphocytes from a primary immunocompetent organ (thymus) and a secondary one (spleen) was investigated over a range of concentrations from 10–12 M to 10–5 M. Lymphocyte chemotaxis was evaluated in a Boyden chamber. The results indicated that 10–5 M of NA inhibits the chemotaxis of lymphocytes from both the immunocompetent organs studied, and that this effect is blocked by either propranolol (10–6 M) or phentolamine (10–5 M). Similarly, 10–5 M of MHPG induced a decrease in the chemotaxis capacity of the lymphocytes. In conclusion, high physiological concentrations of NA and its end metabolite modulate the mobility of lymphocytes, and the participation of both alpha and beta adrenoreceptors is necessary, showing a new aspect of neuroimmune interactions. 相似文献
68.
Heintel T Breinig F Schmitt MJ Meyerhans A 《FEMS immunology and medical microbiology》2003,39(3):279-286
The human cellular immune response against 14 distantly related yeast species was analyzed by intracellular cytokine staining of lymphocytes after ex vivo stimulation of whole blood. While the CD4 T cell response was marginal, extensive MHC class I-restricted CD8 T cell responses were detected against a number of species including spoiling, environmental and human pathogenic yeasts. The yeast-specific CD8 T cells expressed interferon-gamma but lacked expression of CD27 and CCR7, indicating that they were end-differentiated effector memory cells. Mainly intact yeast cells rather than spheroplasts were able to induce cytokine expression in T cells demonstrating that the dominant immunogens were located in the yeast cell wall. Together these data underline the importance of the cellular immune response in protecting humans against yeast and fungal infections. And, from another perspective, recombinant yeast suggests itself as a potential vaccine candidate to efficiently induce antigen-specific CD8 T cell responses. 相似文献
69.
Ortegel JW Staren ED Faber LP Warren WH Braun DP 《Cancer immunology, immunotherapy : CII》2000,48(11):627-634
The purpose of this work was to assess the capacity of tumor-infiltrating leukocytes (TIL) from human non-small-cell lung
carcinoma (NSCLC) specimens to synthesize type-1 and type-2 cytokines. Methods: TIL were isolated from tumors following digestion with collagenase/DNase and further enriched by ficoll-hypaque gradient
centrifugation. Membrane phenotypes and intracellular cytokine protein expression of TIL were assessed by flow cytometry.
Results: The majority of TIL expressed the CD3 antigen with a CD4:CD8 ratio of approximately 2:1. Other leukocytes such as macrophages
(CD14), B lymphocytes (CD20), and natural killer (NK) cells (CD56) were also found to infiltrate the tumors, but in significantly
lower numbers. Owing to the limited recovery of non-CD3+ leukocytes, our analysis of cytokine biosynthesis has focused on T lymphocytes. In the absence of activation, a small percentage
of CD3+ TIL synthesized cytokines ( <4%). Following activation with anti-CD3+interleukin-2 (IL-2), CD3+ TIL synthesized predominantly a type-1 cytokine profile; however, the type-2 cytokines, IL-6 and IL-10, were also detected
in a small percentage of infiltrating cells. Following activation with phorbol 12-myristate 13-acetate + ionomycin, CD3+ TIL also expressed more type-1 than type-2 cytokines and in significantly greater numbers of cells. The CD3+CD8+ component of the TIL synthesized only type-1 cytokines, whereas the CD3+CD4+ component synthesized both type-1 and type-2 cytokines. Conclusion: These results show that the majority of the TIL isolated from NSCLC specimens are T lymphocytes with the capacity to synthesize
type-1 cytokines.
Received: 24 March 1999 / Accepted: 9 September 1999 相似文献
70.
Fas (CD95/Apo-1) exists both in membrane-bound and in biologically active soluble (s) forms. Ligation of membrane-expressed
Fas can induce apoptosis, and Fas-mediated signaling seems to be involved in T-cell-induced apoptosis of human acute myelogenous
leukemia (AML) blasts. The local release of sFas by AML blasts may then function as a protective mechanism by competing with
membrane-bound Fas for binding sites on the common Fas ligand (FasL). sFas was released by AML blasts during in vitro culture,
and this release was modulated by several cytokines that can be secreted by activated T cells. Increased levels of sFas could
be detected during in vitro activation of T cells in the presence of native AML accessory cells, and this was observed both
for (i) mitogenic activation of CD4+ and CD8+ T cell clones derived from acute leukemia patients with therapy-induced leukopenia and (ii) allostimulated activation of
T cells derived from normal donors. However, local in vivo levels of sFas will also be influenced by variations in systemic
levels. High serum levels of sFas were detected in acute leukemia patients during chemotherapy-induced cytopenia, but these
levels decreased during complicating bacterial infections. In contrast, serum levels of sFasL were normal in leukopenic patients.
The present results support the hypothesis that local release of sFas can function as a protective mechanism against AML-reactive
T cells, but the effects of this local release are, in addition, modulated by variations in systemic levels of sFas (but not
sFasL).
Received: 9 March 2000 / Accepted: 25 May 2000 相似文献