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1.
Transforming growth factor beta 1-responsive element: closely associated binding sites for USF and CCAAT-binding transcription factor-nuclear factor I in the type 1 plasminogen activator inhibitor gene. 下载免费PDF全文
A Riccio P V Pedone L R Lund T Olesen H S Olsen P A Andreasen 《Molecular and cellular biology》1992,12(4):1846-1855
2.
Type-1 inhibitor of plasminogen activators (PAI-1) occurs in purified preparations in a latent form that can be activated with denaturants; in vivo, latency is prevented by binding to vitronectin. We have compared latent, denaturant-activated and reactive centre-cleaved human PAI-1 with respect to thermal stability and affinity to monoclonal antibodies. By both criteria, latent and cleaved PAI-1 are very similar or indistinguishable, and clearly different from active PAI-1. Our findings suggest that the conformations of latent and reactive centre-cleaved PAI-1 are similar and resemble the so-called relaxed (R) serpin conformation, while that of active PAI-1 is different and resembles the stressed (S) serpin conformation. 相似文献
3.
The trunk wood of Ocotea cymbarum from the Amazon basin contains α-phellandrene, α-pinene, eugenol, dehydrodieugenol and its monomethyl ether, as well as the previously unknown dehydrodieugenol-B (4,5′-diallyl-2′-hydroxy-2,3′-dimethoxydiphenyl ether). 相似文献
4.
Activation and partial proteolysis of variant glucocorticoid receptors, studied by two-phase partitioning 总被引:1,自引:0,他引:1
In cultured lines of mouse lymphoma cells, resistant to glucocorticoids is frequently associated with the occurrence of glucocorticoid receptors with an abnormally low affinity (nt-) or an abnormally high affinity (nti) for nuclei and DNA. We have investigated whether the abnormal affinities for DNA are correlated with alterations in charge and surface properties of the receptors, that would be revealed through the partition coefficient in aqueous dextran/poly(ethylene glycol) two-phase systems. We have found that none of the receptor variants is defective in the activation step per se, and that only the nti receptors are abnormal in partition properties. Partial proteolysis of wild-type and nt- receptors with alpha-chymotrypsin produces forms which are indistinguishable from the nti receptors with respect to partition coefficients. Upon alpha-chymotrypsin treatment the wild-type receptors attain DNA-binding properties identical to those of the nti receptors, while the nt- receptors, in spite of some increase in DNA affinity, still bind less firmly to DNA than the alpha-chymotrypsin-treated wild-type receptors. alpha-Chymotrypsin treatment of the various receptor types also produces an increase in the binding to dextran sulphate, but the dextran sulphate affinity is higher and varies less between different receptor types than the DNA affinity. Trypsin-treated receptors were found to be devoid of affinity for DNA and dextran sulphate. 相似文献
5.
Peter A. Andreasen 《Biochimica et Biophysica Acta (BBA)/General Subjects》1976,428(3):792-807
The accumulation of glucocorticoid-receptor complex from rat thymocyte cytosol in a thymocyte chromatin preparation has been studied. A thymocyte 100 000 × g supernatant was prepared and the receptor stabilized by the addition of glycerol until 40%. Tritiated glucocorticoid-receptor complex was formed by incubation of this solution with tritiated glucocorticoids at −5°C. The chromatin accumulated part of the complex at incubations at 4°C. Receptor without hormone was not accumulated in the chromatin. The accumulation from cytosol diluted and preincubated at 4°C prior to the addition of the chromatin occurred with a high rate, whereas a low rate was seen without preincubation. This indicated a transformation of the complex during the preincubation. This transformation was found to be obligatory for the accumulation and to be promoted by dilution of the supernatant and by high ionic strength. The transformed and the untransformed complexes differed with respect to partition coefficients in an aqueous dextran-polyethylene glycol two-phase system and in their behaviour during adsorptions with dextran-coated charcoal, where great loss of transformed complex was observed. The accumulation of complex in the chromatin was found to be unsaturable in the concentration interval studied (0.07–0.25 nM). 相似文献
6.
Joseph W. Golden Xiankun Zeng Curtis R. Cline Jeffrey M. Smith Sharon P. Daye Brian D. Carey Candace D. Blancett Charles J. Shoemaker Jun Liu Collin J. Fitzpatrick Christopher P. Stefan Aura R. Garrison 《PLoS pathogens》2022,18(5)
Crimean-Congo hemorrhagic fever virus (CCHFV) is an important human pathogen. In cell culture, CCHFV is sensed by the cytoplasmic RNA sensor retinoic acid-inducible gene I (RIG-I) molecule and its adaptor molecule mitochondrial antiviral signaling (MAVS) protein. MAVS initiates both type I interferon (IFN-I) and proinflammatory responses. Here, we studied the role MAVS plays in CCHFV infection in mice in both the presence and absence of IFN-I activity. MAVS-deficient mice were not susceptible to CCHFV infection when IFN-I signaling was active and showed no signs of disease. When IFN-I signaling was blocked by antibody, MAVS-deficient mice lost significant weight, but were uniformly protected from lethal disease, whereas all control mice succumbed to infection. Cytokine activity in the infected MAVS-deficient mice was markedly blunted. Subsequent investigation revealed that CCHFV infected mice lacking TNF-α receptor signaling (TNFA-R-deficient), but not IL-6 or IL-1 activity, had more limited liver injury and were largely protected from lethal outcomes. Treatment of mice with an anti-TNF-α neutralizing antibody also conferred partial protection in a post-virus exposure setting. Additionally, we found that a disease causing, but non-lethal strain of CCHFV produced more blunted inflammatory cytokine responses compared to a lethal strain in mice. Our work reveals that MAVS activation and cytokine production both contribute to CCHFV pathogenesis, potentially identifying new therapeutic targets to treat this disease. 相似文献
7.
T cell-induced secretion of MHC class II-peptide complexes on B cell exosomes 总被引:4,自引:0,他引:4 下载免费PDF全文
Antigen-specific interactions between B cells and T cells are essential for the generation of an efficient immune response. Since this requires peptide–MHC class II complexes (pMHC-II) on the B cell to interact with TCR on antigen-specific T cells, we have examined the mechanisms regulating the persistence, loss, and secretion of specific pMHC-II complexes on activated B cells. Using a mAb that recognizes specific pMHC-II, we found that activated B cells degrade approximately 50% of pMHC-II every day and release 12% of these pMHC-II from the cell on small membrane vesicles termed exosomes. These exosomes directly stimulate primed, but not naïve, CD4 T cells. Interestingly, engagement of antigen-loaded B cells with specific CD4 T cells stimulates exosome release in a manner that can be mimicked by pMHC-II crosslinking. Biochemical studies revealed that the pMHC-II released on exosomes was previously expressed on the plasma membrane of the B cells, suggesting that regulated exosome release from activated B cells is a mechanism to allow pMHC-II to escape intracellular degradation and decorate secondary lymphoid organs with membrane-associated pMHC-II complexes. 相似文献
8.
Plasminogen activators catalyse conversion of inhibitor from fibrosarcoma cells to an inactive form with a lower apparent molecular mass 总被引:8,自引:0,他引:8
Purified approximately 54 kDa plasminogen activator inhibitor from human fibrosarcoma cells was converted to an inactive form with slightly higher electrophoretic mobility by incubation with catalytic amounts of urokinase-type or tissue-type plasminogen activator. Serine proteinase inhibitors and a monoclonal antibody against urokinase-type plasminogen activator inhibited the conversion, indicating that it was caused by plasminogen activator-catalyzed proteolysis. These findings represent the first demonstration of a well-defined protein apart from plasminogen, constituting a substrate for plasminogen activators. 相似文献
9.
Aura E. Star 《American journal of botany》1970,57(10):1145-1149
Meiocytes in three morphologically similar but cytologically different wild populations of Claytonia virginica L. were examined. Over a three-year period levels of spontaneous chromosome breakage were consistent for each population but differed between populations. Random samples of inflorescences from two of the populations were treated with 0.005 % aqueous solutions of nucleic acid precursors: adenine, adenosine, thymine, thymidine, guanosine 5'-monophosphate (GMP), and cytosine 5'-monophosphate (CMP). Statistically significant increases in chromosome breakage were observed in the population with little background breakage when inflorescences were treated with adenosine, thymine, thymidine, GMP, and CMP. In the population with moderate spontaneous breakage, a significant increase was observed only in plants treated with adenosine. Breakage induced with nucleic acid precursors was similar to that which occurred spontaneously; the predominant aberration was the single bridge. 相似文献
10.