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排序方式: 共有452条查询结果,搜索用时 62 毫秒
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A Guha 《Journal of molecular biology》1971,56(1):53-62
3.
B Mukherji A Guha R Loomis M T Ergin 《Journal of immunology (Baltimore, Md. : 1950)》1987,138(6):1987-1991
The cytotoxic host immune response toward autologous human cancer may be regulated by the immunoregulatory network. Here we show that helper T cells, cloned from peripheral blood lymphocytes that were sensitized in vitro against an autologous human malignant paraganglioma, proliferated against and made interleukin 2 when cocultured with the tumor-associated antigen in the presence of autologous accessory cells. Furthermore, the helper cell clones amplified cytotoxic immune response by peripheral blood lymphocytes against the paraganglioma cells in coculture with the blood lymphocytes and the paraganglioma cells. An autologous T cell line bearing suppressor phenotype, established from a lymph node that had been infiltrated with the paraganglioma tumor cells, in contrast to the helper cells, selectively suppressed the cytotoxic immune response by the blood lymphocytes against the paraganglioma cells in identical coculture. These results, therefore, demonstrate the existence of cell-mediated immunologic regulations of the cytotoxic immune response (concurrent amplification and suppression in the same host) against an autologous human tumor. 相似文献
4.
B Mukherji S A Wilhelm A Guha M T Ergin 《Journal of immunology (Baltimore, Md. : 1950)》1986,136(5):1888-1892
The potential existence of down-regulation of cytotoxic immune response against an autologous human melanoma line was investigated as a possible explanation for cytotoxic unresponsiveness against the autologous melanoma cells. The melanoma cell line, PJ-M, was established and lymph node resident lymphocytes (LNL) were isolated from a lymph node which was partially infiltrated with the melanoma cells. Autologous peripheral blood lymphocytes (PBL) were sensitized in in vitro co-culture (IVC) against radiated PJ-M cells in the presence or absence of PJ-M-sensitized LNL and enriched suppressor (OKT8+) or inducer (OKT4+) LNL populations, and were assayed for cytotoxicity in a 4-hr 51Cr-release microcytotoxicity assay. Significant cytotoxic response against PJ-M could be generated in the PBL, but not in the LNL. The addition of sensitized, unfractionated LNL, OKT8+, or OKT4+ LNL populations abrogated cytotoxic response in the PBL against PJ-M. The suppression of cytotoxic response was induced selectively against the PJ-M targets, because IVC of PBL in the presence of the sensitized LNL did not affect the generation of polyclonal cytotoxic alloreactivities, nor did they abrogate the generation of cytotoxic response against allogeneic targets in IVC against the corresponding allogeneic targets. These results suggest the possibility that cytotoxic immune response against the autologous melanoma cells might have been suppressed by the individual's own immunoregulatory circuit. 相似文献
5.
Summary Irradiated styrene-grafted cellulose acetate membrane was used for the separation of ethanol by reverse osmosis. Ethanol separation from molasses based fermentation broth resulted in separation efficiency of 90% at an operating pressure of 1400 psig. Lower permeate flux was observed with fermented broth compared to aqueous ethanol. 相似文献
6.
A Guha W Szybalski W Salser E P Geiduschek J F Pulitzer A Bolle 《Journal of molecular biology》1971,59(2):329-349
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The use of C14-labelled substrate in histochemical demonstration of different forms of phosphorylase
Active and total phosphorylase activity, using labelled C14-glucose-1-phosphate as the substrate, is demonstrated by histoautoradiographic method. This method can demonstrate the polysaccharide
synthesizedin vitro by phosphorylase without intervention from the unlabelled pre-existing glycogen.
C14-glucose can not replace C14-glucose-1-phosphate as substrate.
The distribution of phosphorylase in tissue sections, except in cases of very low activity, is similar to that obtained by
customary dilute Lugol's iodine staining method. The relative difference of intensity between active and total phosphorylase,
as revealed by iodine staining, is also reflected by histoautoradiographic method.
Histoautoradiographic method has several advantages over the iodine staining method. This method is more sensitive for demonstration
of very low phosphorylase activity which may escape detection by iodine staining. Branching enzyme activity, especially when
it favors synthesis of glycogen type of polysaccharide instead of amylopectin type, can be better detected by this method.
Active phosphorylase substrate medium can be used to demonstrate this activity in plant tissues, where the presence of pre-existing
starch often prohibits the use of iodine staining method.
Stripping film method for autoradiography is recommended for the study of this enzyme activity. 相似文献
10.
E Waxman J B Ross T M Laue A Guha S V Thiruvikraman T C Lin W H Konigsberg Y Nemerson 《Biochemistry》1992,31(16):3998-4003
We find that the isolated, extracellular domain of tissue factor (TF1-218; sTF) exhibits only 4% of the activity of wild-type transmembrane TF (TF1-263) in an assay that measures the conversion of factor X to Xa by the TF:VIIa complex. Further, the activity of sTF is manifest only when vesicles consisting of phosphatidylserine and phosphatidylcholine (30/70 w/w) are present. To determine whether the decreased activity results from weakened affinity of sTF for VIIa, we studied their interaction using equilibrium ultracentrifugation, fluorescence anisotropy, and an activity titration. Ultracentrifugation of the sTF:VIIa complex established a stoichiometry of 1:1 and an upper limit of 1 nM for the equilibrium dissociation constant (Kd). This value is in agreement with titrations of dansyl-D-Phe-L-Phe-Arg chloromethyl ketone active site labeled VIIa (DF-VIIa) with sTF using dansyl fluorescence anisotropy as the observable. Pressure dissociation experiments were used to obtain quantitative values for the binding interaction. These experiments indicate that the Kd for the interaction of sTF with DF-VIIa is 0.59 nM (25 degrees C). This value may be compared to a Kd of 7.3 pM obtained by the same method for the interaction of DF-VIIa with TF1-263 reconstituted into phosphatidylcholine vesicles. The molar volume change of association was found to be 63 and 117 mL mol-1 for the interaction of DF-VIIa with sTF and TF1-263, respectively. These binding data show that the sTF:VIIa complex is quantitatively and qualitatively different from the complex formed by TF1-263 and VIIa. 相似文献