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131.
A. Giuliani E. Calappi E. Mineo M. G. Neri A. Gallina A. Pessina 《Molecular and cellular biochemistry》1995,152(2):103-112
The murine leukemia cell lines L1210 and WEHI-3B show a very different sensitivity to the cholera toxin (CT).Thein vitro growth of L1210 is completely inhibited by 10–8 M CT, while WEHI-3B growth shows the same inhibition at 10–11 M.The analysis of membrane ganglioside pattern of the two cell lines shows that in L1210 cells the major component is the GM1a ganglioside while the monosialoganglioside fraction from WEHI-3B is entirely composed of gangliosides of the b series among which GM1b is the more represented. The total cholera toxin binding capacity of the ganglioside extract from L1210 cells is more than hundred fold higher than that of WEHI-3B and this difference is also confirmed by the number of CT receptors/cell and by the binding of FITC-B subunit of CT on the cells. These surprising data are in conflict with the poor sensitivity to CT evidenced by L1210 compared to WEHI-3B cells.In order to clarify this discrepancy we investigated the cAMP accumulation, the cell viability and the clonogenicity of these two leukemia cell lines following the treatment with CT and forskolin (FRSK).The treatment of WEHI-3B cells with CT induces a dramatic increase of intracellular cAMP which highly correlates with cell death and the decrease of clonogenicity and this result is partially obtained by the treatment with FRSK, L1210 cells do not evidence significant cAMP accumulation neither with CT nor with FRSK treatment.These data suggest that the different inhibiting effect of CT on WEHI-3B and L1210 cells does not correlate with their different pattern of gangliosides and the related toxin binding capacity. Further they indicate that the growth inhibition of WEHI-3B cells is closely related with a cAMP-dependent cell killing mechanism, while the inhibition of L1210 growth (produced by high concentration of CT) is mediated by a cAMP independent mechanism. 相似文献
132.
Luca M. Neri Frank O. Fackelmayer Marina Zweyer Terumi Kohwi-Shigematsu Alberto M. Martelli 《Chromosoma》1997,106(2):81-93
The nuclear matrix, a proteinaceous entity thought to be a scaffolding structure that determines the higher order organization
of eukaryotic chromatin, is usually prepared from intact nuclei by a series of extraction steps. In most cell types investigated,
the nuclear matrix does not spontaneously resist these extractions, but must rather be stabilized before the application of
extracting agents such as high salt solutions or lithium diiodosalicylate. We have examined the effect of two widely used
stabilization procedures on the localization of nuclear matrix proteins. Four individual polypeptides were studied, all of
which are scaffold or matrix-associated region (S/MAR)-binding proteins: SATB1, SAF-A/hnRNP-U, NuMA , and topoisomerase II
α. Nuclei were isolated from K562 human erythroleukemia cells in a buffer containing spermine, spermidine, KCl and EDTA, and
the nuclear matrix or scaffold was obtained by extraction with lithium diiodosalicylate after stabilization by heat treatment
(37° or 42°C) or incubation with Cu2+ ions. When the localization of individual proteins was determined by immunofluorescent staining and confocal scanning laser
microscopy, markedly different consequences of the two stabilization strategies became evident, ranging from a total maintenance
of the localization (NuMA and topoisomerase II α) to a marked redistribution (SATB1 and SAF-A/hnRNP-U). Our results seem to
indicate that a reevaluation of stabilization protocols employed for the preparation of the nuclear matrix is desirable, especially
by performing morphological controls.
Received: 22 January 1997; in revised form: 17 February 1997 / Accepted: 21 February 1997 相似文献
133.
134.
Luca M. Neri Caterina Cinti Spartaco Santi Marco Marchisio Silvano Capitani Nadir M. Maraldi 《Histochemistry and cell biology》1997,107(2):97-104
DNA sequences digested by HaeIII and reconstructed by in situ nick translation employing digoxigenin-labelled nucleotides are usually revealed either by
horseradish peroxidase or FITC fluorescence. To obtain a significant improvement in terms of resolution, sensitivity and specificity,
colloidal gold has been used instead of FITC (as the reporter molecule) to reveal the labelled DNA. Colloidal gold and propidium
iodide were visualised by employing the reflectance mode and the 488-nm laser line of a confocal laser scanning microscope.
In chromosomes, the fluorescent reaction pattern showed diffuse areas of labelling in which it was impossible to identify
any specific kind of banding along the arms. In some chromosomes and, in particular, 1 and 9, a C-negative banding due to
the negativity of the centromeric areas was seen. A more accurate localisation on chromosomes, including telomeric regions,
often organised in spot pairs that resembled an R-like banding, was detected using 1-nm colloidal gold. A fine labelling was
also demonstrated in nuclei, especially at their peripheral heterochromatin. The non-fading properties of colloidal gold combined
with visualisation by reflectance confocal laser scanning microscopy demonstrated the possibility of obtaining a higher spatial
resolution than when using conventional fluorophores or higher laser wavelength. This improved way to study the localization
of HaeIII digestion sites in single chromosomes and in interphase nuclei made the reaction a valuable tool for the detection of
antigens or of specific DNA sequences in biological preparations.
Accepted: 5 September 1996 相似文献
135.
136.
G Neri D F Smith E B Gilliam E F Walborg 《Archives of biochemistry and biophysics》1974,165(1):323-330
Novikoff ascites hepatoma cells were highly agglutinable by the plant lectins concanavalin A and wheat germ agglutinin. Treatment of the intact cells with papain released from the cell surface a glycopeptide fraction which possessed concanavalin A and wheat germ agglutinin receptor activity, as judged by its ability to inhibit lectin-induced hemagglutination. A component of the cell-surface glycopeptide fraction, excluded from Sephadex G-50, possessed lectin receptor activities reflecting the cytoagglutination properties of the intact cells from which it was derived. Further resolution of this component by pronase digestion, gel filtration, and ion-exchange chromatography resulted in the isolation of sialoglycopeptides which exhibited potent and specific concanavalin A receptor activity. 相似文献
137.
138.
Ilan Arad Graciela C. Lijovetzky Ruth Starinsky Neri Laufer Tirza Cohen 《Human genetics》1980,53(2):275-277
Summary It is known from the literature that total loss of the short arm causes complete Turner's signs (Hoo, 1975; Therman and Patau, 1974). Partial deletions of the short arm of the X chromosome are in some cases compatible with fertility (Fraccaro et al., 1977; Hoo, 1979), but in other cases they cause a significant ovarial insufficiency with Turner's signs (Giraud et al., 1974) or gonadal dysgenesis (Petrinelli et al., 1978). A common sign for all the patients having the Xp-wwith the break point in the dark band (p113-p21) seems to be a short stature. The presence of other clinical signs is rather irregular. In this work, a 25-year-old female patient having a Xp deficiency in region p21 (46,X,del(X) (qterp21:)) with short stature, primary amenorrhea, sterility, and clear Turner's is described. 相似文献
139.
Effect of dibutyryl cyclic AMP on interferon production by cells treated with viral or nonviral inducers. 1 总被引:2,自引:0,他引:2
140.