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1.
Endogenous CD8+ T cell expansion during regression of monoclonal EBV-associated posttransplant lymphoproliferative disorder. 总被引:5,自引:0,他引:5
V P Khatri R A Baiocchi R Peng A R Oberkircher J M Dolce P M Ward G P Herzig M A Caligiuri 《Journal of immunology (Baltimore, Md. : 1950)》1999,163(1):500-506
There are experimental data which suggest that the primary immune effector cell responsible for maintaining immune surveillance against the outgrowth of EBV-transformed B cells in humans is the CTL, but in vivo proof of this is lacking. In this study we perform a series of cellular and molecular assays to characterize an autologous, endogenous immune response against a transplantation-associated, monoclonal, EBV+ posttransplant lymphoproliferative disorder (PTLD). Following allogeneic bone marrow transplantation, a patient developed a monoclonal PTLD of donor B cell origin. With a decrease in immune suppression, we document the emergence of endogenous, donor-derived CD3+CD8+ CTLs, followed by regression of the PTLD. The TCR Vbeta repertoire went from a polyclonal pattern prior to the development of PTLD to a restricted TCR Vbeta pattern during the outgrowth and regression of PTLD. Donor-derived CD3+CD8+ T lymphocytes displayed MHC class I-restricted cytolytic activity against the autologous EBV+ B cells ex vivo without additional in vitro sensitization. The striking temporal relationship between the endogenous expansion of a TCR Vbeta-restricted, CD3+CD8+ population of MHC class I-restricted CTL, and the regression of an autologous monoclonal PTLD, provides direct evidence in humans that endogenous CD3+CD8+ CTLs can be responsible for effective immune surveillance against malignant transformation of EBV+ B cells. 相似文献
2.
B.S. Rathaur G.S. Khatri K.C. Gupta C.K. Narang N.K. Mathur 《Analytical biochemistry》1981,112(1):55-59
A new reagent (blue guaran) for quantitative estimation of lectins, has been derived from a galactomannan (guaran). When the lectin solution is added to an aqueous solution of blue guaran, dye-bound guaran is precipitated from the solution. The difference in absorbance of the blue guaran solution before and after the addition of lectin solution is proportional to the amount of lectin present in the sample. The method of preparation of blue guaran, its spectral characteristics and effect of pH on precipitation have also been described. It gives a simple colorimetric method for the estimation of galactose-specific lectins. 相似文献
3.
4.
Indu S. Ambudkar Timothy Lockwich Yukiharu Hiramatsu Bruce J. Baum 《Molecular and cellular biochemistry》1992,114(1-2):73-77
Conclusions While it is generally accepted that Ca2+ plays an important regulatory role in the physiology of a number of non-excitable cells, the mechanisms which regulate intracellular [Ca2+ are far from well established. Ca2+ transporting mechanisms which distribute Ca2+ intracellularly as well as those which allow influx of extracellular Ca2+ are involved in mediating intracellular Ca2+ homestasis. In this paper we have described recent studies on the regulation of the Ca2+ influx system in the data, it appears that the process of Ca2+ entry is extremely complex and may involve several levels of regulation. Understanding the molecular basis of these regulatory mechanisms presents a challeging problem for future studies. 相似文献
5.
Valerie J. Horn Paul A. Sheehy Miriam B. Goodman Indu S. Ambudkar 《Molecular and cellular biochemistry》1991,101(1):43-49
Intracellular Ca2+ mobilization events were assessed in mouse L cells, which contain native prostaglandin E1 receptors and transfected human 2 adrenergic receptors. Both Fura2 (single cell measurements) and Quin 2, (cuvette assays) were used to determine [Ca2+]i levels. Our results demonstrate that in the transfected cells there is a dose-dependent increase in [Ca2+]i in response to isoproterenol (0.1 nM–100 nM), which is inhibited by the -adrenergic antagonist, propranolol, and is a result of intracellular Ca2+ release. [Ca2+]1 in these cells was also increased by prostaglandin E1, 8 bromo cyclic AMP, and aluminum fluoride. Both 8 bromo cAMP and isoproterenol induced a rapid increase in the levels of IP1, IP2, and IP3. The data presented demonstrate that the elevation of intracellular cyclic AMP induces an increase in IP3 production which leads to an elevation in [Ca2+];. We propose that this cyclic AMP dependent activation of the IP3 generating system occurs at a post-receptor site.Abbreviations cAMP
Adenosine Cyclic 3-5-Monophosphate
- [Ca2+]i
intracellular [Ca2+]i
- 8 Br cAMP
8 Bromo Adenosine Cyclic 3-5-Monophosphate
- DAG
Diacylglycerol
- EGTA]
[Ethylene Bis (oxyethylenenitrilo)] Tetracetic acid
- BSA
Bovine Serum Albumin
- HBSS-H
Hanks' Balanced Salt Solution buffered with HEPES to pH 7.4
- HEPES
4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid
- PIP2
Phosphatidylinositol 4,5-bisphosphate
- IP2
Inositol 4 Phosphate
- IP2
Inositol 4,5 Bisphosphate
- IP3
Inositol Trisphosphate
- PGE1
Prostaglandin E1
- PBS
Phosphate Buffered Saline Solution 相似文献
6.
A. Jayakumaran Nair G. S. Khatri I. M. Santha S. L. Mehta 《Journal of plant biochemistry and biotechnology.》1994,3(2):103-106
A gene responsible for the degradation of ß-N-Oxalyl diaminopropionic acid (ODAP) was fused to the maIE gene, which codes for maltose binding protein, by cloning into an expression vector pMAL c2. The gene has been expressed as fusion protein of mol wt approximately 62 kD. It has been purified by affinity chromatography. The fusion protein has been cleaved by an endoprotease factor Xa and the presence of maltose binding protein and the product of the cloned gene confirmed. SDS-PAGE has shown that the product of the ODAP degrading gene is a single polypeptide of mol wt of about 20.7 kD. 相似文献
7.
Yukiharu Hiramatsu Indu S. Ambudkar Bruce J. Baum 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1991,1092(3):391-396
β-Adrenergic receptor stimulation of adenylyl cyclase involves the activation of a GTP-binding regulatory protein (G-protein, termed here Gs). Inactivation of this G-protein is associated with the hydrolysis of bound GTP by an intrinsic high affinity GTPase activity. In the present study, we have characterized the GTPase activity in a Gs-enriched rat parotid gland membrane fraction. Two GTPase activities were resolved; a high affinity GTPase activity displaying Michaelis-Menten kinetics with increasing concentrations of GTP, and a low affinity GTPase activity which increased linearly with GTP concentrations up to 10 mM. The β-adrenergic agonist isoproterenol (10 μM) increased the Vmax of the high affinity GTPase component approx. 50% from 90 to 140 pmol/mg protein per min, but did not change its Km value (≈ 450 nM). Isoproterenol also stimulated adenylyl cyclase activity in parotid membranes both in the absence or presence of GTP. In the presence of a non-hydrolyzable GTP analogue, guanosine 5′-(3-O-thio)triphosphate (GTPγS), isoproterenol increased cAMP formation to the same extent as that observed with AlF4?. Cholera toxin treatment of parotid membranes led to the ADP-ribosylation of two proteins (≈ 45 and 51 kDa). Cholera toxin also specifically decreased the high affinity GTPase activity in membranes and increased cAMP formation induced by GTP in the absence or the presence of isoproterenol. These data demonstrate that the high affinity GTPase characterized here is the ‘turn-off’ step for the adenylyl cyclase activation seen following β-adrenergic stimulation of rat parotid glands. 相似文献
8.
G Xu L J Huan I A Khatri D Wang A Bennick R E Fahim G G Forstner J F Forstner 《The Journal of biological chemistry》1992,267(8):5401-5407
When subjected to thiol reduction, purified intestinal mucins have been shown to undergo a decrease in molecular mass and to liberate a 118-kDa glycopeptide (Roberton, A. M., Mantle, M., Fahim, R. E. F., Specian, R., Bennick, A., Kawagishi, S., Sherman, P., and Forstner, J. F. (1989) Biochem. J. 261, 637-647). The latter has been called a putative "link" component because it is assumed to be important for disulfide bond-mediated mucin polymerization. Controversy exists as to whether the putative link is an integral mucin component or a separate mucin-associated glycopeptide. In the present study both NH2-terminal and internal amino acid sequences of the 118-kDa glycopeptide of rat intestinal mucin were used to generate opposing oligonucleotide primers for polymerase chain reaction. A specific 1.2-kilobase (kb) product was obtained, from which a 0.5-kb HindIII fragment was used as a probe to screen a lambda ZAP II cDNA library of rat intestine. A 2.6-kb cDNA (designated MLP 2677) was sequenced and revealed an open reading frame of 2.5 kb encoding 837 amino acids. The deduced amino acid sequence showed that the putative link peptide is equivalent to the carboxyl-terminal 689 amino acids of a larger peptide. Northern blots revealed a mRNA size of approximately 9 kb. Computer searches revealed no sequence homology with other proteins, but similarities were seen in the alignment of cysteine residues in the link and in several domains of human von Willebrand factor, as well as cysteine-rich areas of bovine and porcine submaxillary mucins and a frog skin mucin designated FIM-B.1. In keeping with earlier demonstrations of the presence of mannose in the 118-kDa glycopeptide, there were several (13) consensus sequences for attachment of N-linked oligosaccharides within the link domain. Further sequencing of MLP 2677 in a direction 5' to the codon specifying the NH2-terminal proline of the link has revealed a coding region for 148 amino acids, including a unique 75-amino acid domain rich in cysteine and proline, and a region containing 4.5-variable tandem repeats (each 11-12 amino acids) rich in serine, threonine, and proline. The presence of mucin-like tandem repeats suggests that the entire cysteine-rich link peptide represents the carboxyl-terminal region (75.5 kDa) of a mucin-like peptide (MLP). The latter is estimated to have a molecular mass of approximately 300 kDa. 相似文献
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10.