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Fiorenzo A. Peverali Maurizio D'Esposito Dario Acampora Giuseppe Bunone Mario Negri Antonio Faiella Anna Stornaiuolo Maria Pannese Enrica Migliaccio Antonio Simeone Giuliano Della Valle Edoardo Boncinelli 《Differentiation; research in biological diversity》1990,45(1):61-69
Mammalian genes containing a class-I homeobox (HOX genes) are highly expressed in the embryonic nervous system. As a first step towards the molecular analysis of the role these genes play in neural cells, we studied the expression of four human HOX genes in five neuroblastoma (NB) cell lines - SK-N-BE, CHP-134, IMR-32, SK-N-SH and LAN-1 - during the process of differentiation induced by treatment with retinoic acid (RA). The four genes, HOX1D, 2F, 3E and 4B, located at corresponding positions in the four HOX loci, share a high degree of sequence similarity with the Drosophila Deformed homeotic gene and constitute a homology group, group 10. One of these genes, HOX1D, is not expressed in the cells used, whereas the other three are highly expressed in untreated and RA-induced NB cells, even though the expression pattern in the various lines is slightly different for the three genes. Our analysis reveals a complex and specific expression pattern in these lines, paving the way to an identification of different NB-cell populations by means of specific HOX gene expression schemes. On the other hand, in every line studied, morphological maturation toward a neuronal differentiated phenotype appears to be associated with increased HOX gene expression. 相似文献
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Purification and properties of two lectins from the latex of the euphorbiaceous plants Hura crepitans L. (sand-box tree) and Euphorbia characias L. (Mediterranean spurge). 下载免费PDF全文
L Barbieri A Falasca C Franceschi F Licastro C A Rossi F Stirpe 《The Biochemical journal》1983,215(3):433-439
1. From the latex of two members of the plant family Euphorbiaceae, Hura crepitans L. (sand-box tree) and Euphorbia characias L. (Mediterranean spurge), two lectins were purified by affinity chromatography on acid-treated Sepharose 6B followed by elution with D-galactose. 2. The lectin from E. characias is a single molecular species with Mr 80 000, made up of two identical subunits with Mr 40 000, and is a glycoprotein containing 11% carbohydrate. 3. The lectin from H. creptians appears as a mixture of three isolectins with Mr 140 000, consisting of four different subunits with Mr values 37 500, 35 500, 31 000, and 29 000. 4. Both lectins have haemagglutinating activity, with no specificity for human blood groups. The haemagglutinating activity is inhibited by D-galactose and by galactose-containing oligosaccharides. 5. The lectin from H. crepitans is mitogenic to human T-, but not to B-, lymphocytes. The latex of E. characias is mitogenic to T- and, to a lesser extent, to B-, lymphocytes, but the purified E. characias lectin has no mitogenic activity. 6. The lectin from H. crepitans, but not that from E. characias, inhibits protein synthesis by a rabbit reticulocyte lysate. 相似文献
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Properties of the xanthine oxidase from human liver 总被引:4,自引:0,他引:4
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Regulation of ascorbic acid and of xylulose synthesis in rat-liver extracts. The effect of starvation on the enzymes of the glucuronic acid pathway 下载免费PDF全文
1. Control of enzyme formation has been examined in the pathways degrading mandelate and p-hydroxymandelate in Pseudomonas fluorescens. 2. The first three enzymes form a group which is common to both pathways and which is co-ordinately induced or repressed. The genes controlling these enzymes are assumed to form a ;regulon'. This group of enzymes is induced by mandelate or p-hydroxymandelate and repressed by benzoate and by p-hydroxybenzoate (the immediate end products resulting from the action of this group of enzymes). 3. Repression is independently exerted by end products of enzymes controlled by succeeding regulons, i.e. by catechol, by protocatechuate and finally by succinate and acetate. 4. The pattern is repeated further along the pathway, so that benzoate oxidase (controlled by the second regulon) is repressed by its immediate end product, catechol, and again by succinate and acetate. 5. Pyrocatechase, an enzyme controlled by the third regulon, is repressed by succinate and acetate. 6. There is a parallel system of multi-sensitive repression mechanisms controlling production of the enzymes that degrade the hydroxy compounds. Again, the enzymes of each regulon are repressed by the immediate end product of their action and by the end products of each succeeding group of enzymes. 7. Repressor activity appears to be exerted by compounds that are likely to occur as such in the external environment or that occur at points of convergence of the degradative pathways of the cell. 8. The net effect of this control system, involving both induction and end-product repression, appears to be that cells will not form inducible degradative enzymes if the end products are already being supplied from without or are being produced by degradation of some alternative source of carbon and energy. 相似文献
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G. Porro A. Bolognesi P. Caretto G. Gromo P. Lento G. Mistza T. Sciumbata F. Stirpe D. Modena 《Cancer immunology, immunotherapy : CII》1993,36(5):346-350
An anti-CD5 monoclonal antibody (mAb) was linked to the plant toxin momordin, a type-1 ribosome-inactivating protein purified fromMomordica charantia. The in vitro cytotoxicity of the immunotoxin was evaluated as the inhibition of protein and/or DNA synthesis on isolated peripheral blood mononuclear cells (PBMC) and on human T cell leukemia Jurkat. The potency of the immunotoxin on PBMC was very high (IC50 = 1–10 pM) and was not affected by blood components. The conjugate was also very efficient in the inhibition of the proliferative response in a mixed lymphocyte reaction (IC50 = 10 pM). Moreover, the in vitro performances of the immunotoxin compared favourably with those reported for other anti-CD5-based immunoconjugates containing ricin A chain. The in vivo activity of the immunotoxin was assessed in the model ofnu/nu mice bearing Jurkat leukemia. A significant inhibition of the tumour development (80%,P <0.01) in the animals treated with immunotoxin was observed. Taken together, the in vitro and in vivo results suggest that the anti-CD5-momordin conjugate may be useful for graft-versus-host disease therapy and potentially in the treatment of CD5-positive leukemias and lymphomas. 相似文献
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Ursula J. Behrens Fiorenzo Paronetto 《In vitro cellular & developmental biology. Plant》1984,20(5):391-395
Summary In our laboratory, airborne yeast contaminants of cell cultures have consistently been of the genusCandida (speciesCandida parapsilosis), which are difficult to control with fungicidal agents. To salvage cell lines that show the presence of this fungus, two
effective methods may be employed. In early stages of infection, the addition of activated mouse peritoneal macrophages (5×105 cells/ml) to the culture medium containing 5 μg Fungizone/ml eliminates all spores by phagocytosis. More heavily contaminated
cultures can be depleted of fungi by density centrifugation on a layer of 38% Percoll. Remaining single spores, often not
detectable by light microscopy, can be removed by the addition of macrophages (2×105/ml) and Fungizone (5 μg/ml) to the culture medium. Contaminated monolayer cells can be freed of blastospores by several washes
with balanced salt solution and subsequent culturing for 4 d in medium containing 10 μg Fungizone/ml without any toxic effects
to the cells. These procedures can rescue valuable cell lines and hybridomas that would otherwise be lost.
This work was supported by Veterans Administration Research Funds. 相似文献
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