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71.
This work lies within the framework of a broader project aimed at exploring the realm of all possible folded polypeptides; the main question addressed here is whether the corresponding RNAs also assume a folded conformation. We present an investigation on the structural properties of de novo, totally random RNAs by means of the 'RNA Foster' assay. Experimental results show that all RNAs studied are folded at 37 degrees , so that fold seems to be a common feature of RNAs. Random RNAs' fold shows a surprising thermal stability with an average T(m) value at ca. 50 degrees which prompts the idea that thermo-stable structures might not be as rare as they are commonly thought to be. The results are discussed within the general framework of random RNA properties such as those that might have been produced in a prebiotic scenario. 相似文献
72.
Celegato B Capitanio D Pescatori M Romualdi C Pacchioni B Cagnin S Viganò A Colantoni L Begum S Ricci E Wait R Lanfranchi G Gelfi C 《Proteomics》2006,6(19):5303-5321
73.
Nanoporous surfaces as harvesting agents for mass spectrometric analysis of peptides in human plasma
Gaspari M Ming-Cheng Cheng M Terracciano R Liu X Nijdam AJ Vaccari L di Fabrizio E Petricoin EF Liotta LA Cuda G Venuta S Ferrari M 《Journal of proteome research》2006,5(5):1261-1266
Silica-based nanoporous surfaces have been developed in order to capture low molecular weight peptides from human plasma. Harvested peptides were subjected to mass spectrometric analysis by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a means of detecting and assessing the bound molecules. Peptide profiles consisting of about 70 peaks in the range 800-10,000 m/z were generated. The method could allow detection of small peptides at ng/mL concentration levels, either in standard solutions or in plasma. The same molecular cutoff effect was observed for mixtures of standard proteins and peptides incubated with silicon-based nanoporous surfaces. 相似文献
74.
Elisa Redaelli Rita Restano Cassulini Deyanira Fuentes Silva Herlinda Clement Emanuele Schiavon Fernando Z. Zamudio George Odell Annarosa Arcangeli Jeffrey J. Clare Alejandro Alag��n Ricardo C. Rodr��guez de la Vega Lourival D. Possani Enzo Wanke 《The Journal of biological chemistry》2010,285(6):4130-4142
75.
Tettamanti G Malagoli D Marchesini E Congiu T de Eguileor M Ottaviani E 《Cell and tissue research》2006,326(1):179-186
Functional and morphological modifications in the IPLB-LdFB insect cell line were examined following a short treatment with a reversible inhibitor of mitochondrial ATP synthase, oligomycin A, and subsequent incubation for various times in oligomycin-A-free medium. Oncosis, apoptosis and autophagy at variable percentages were observed under the various experimental conditions. Together with oncotic and apoptotic pathways that lead directly to cell death, the insect cells responded to ATP depletion with autophagy. Our results revealed that, in most cases, autophagy failed to restore cellular homeostasis, probably because of a massive sequestration of mitochondria in autophagic vacuoles. This critical event was a “point of no return” and ultimately resulted in cell necrosis. However, cells with a misshapen body and nucleus resembling “resistant forms” were observed at the end of the experiments. Our findings indicate that oligomycin-A-induced autophagy can promote cell protection or cell destruction and is an open-ended process that can lead to survival or death depending on a combination of concomitant factors.This work was supported by MIUR (Italy) grants to M.deE. and E.O. and by the Centro Grandi Attrezzature (University of Insubria, Varese, Italy).Gianluca Tettamanti and Davide Malagoli contributed equally to this work. 相似文献
76.
Agostinelli E Belli F Molinari A Condello M Palmigiani P Vedova LD Marra M Seiler N Arancia G 《Biochimica et biophysica acta》2006,1763(10):1040-1050
In situ formation of cytotoxic metabolites by an enzyme-catalyzed reaction is a recent approach in cancer chemotherapy. We demonstrate that multidrug resistant human melanoma cells (M14 ADR) are more sensitive than the corresponding wild type cells (M14 WT) to hydrogen peroxide and aldehydes, the products of bovine serum amine oxidase (BSAO)-catalyzed oxidation of spermine. Hydrogen peroxide was mainly responsible for the loss of cell viability. With about 20%, the aldehydes formed from spermine contribute also to cytotoxicity. Elevation of temperature from 37 degrees C to 42 degrees C decreased survival of both cell lines by about one log unit. Pre-treatment with N1,N4-bis(2,3-butadienyl)-1,4-butanediamine (MDL 72527), a lysosomotropic compound, sensitized cells to toxic spermine metabolites. MDL 72527 (at 300 microM) produced in M14 cells numerous cytoplasmic vacuoles which, however, disappeared by 24 h, even in the presence of the drug. Mitochondrial damage, as observed by transmission electron microscopy, correlated better with the cytotoxic effects of the treatment than vacuole formation. Since the release of lysosomal enzymes causes oxidative stress and apoptosis, we suggest that the lysosomotropic effect of MDL 72527 is the major reason for its sensitizing effect. 相似文献
77.
A fragment of a putative L-type Ca(2+) channel has been identified by molecular biology experiments in immunocytes from the mussel Mytilus galloprovincialis. Using the cell permeable and Ca(2+)-specific fluorochrome FURA 2-AM, we have demonstrated that the algal toxin yessotoxin (YTX) is able to increase intracellular Ca(2+) concentration in M. galloprovincialis immunocytes. The YTX effect on Ca(2+) increase is inhibited by the L-type Ca(2+) channel inhibitor, verapamil, which is cAMP- and cGMP-dependent, but PKA- and nitric oxide-independent. On the basis of these observations, a possible role for YTX as a potential disturber of mussel immune efficiency is suggested. 相似文献
78.
79.
Zaharenko AJ Schiavon E Ferreira WA Lecchi M de Freitas JC Richardson M Wanke E 《Peptides》2012,34(1):158-167
During their evolution, animals have developed a set of cysteine-rich peptides capable of binding various extracellular sites of voltage-gated sodium channels (VGSC). Sea anemone toxins that target VGSCs delay their inactivation process, but little is known about their selectivities. Here we report the investigation of three native type 1 toxins (CGTX-II, δ-AITX-Bcg1a and δ-AITX-Bcg1b) purified from the venom of Bunodosoma cangicum. Both δ-AITX-Bcg1a and δ-AITX-Bcg1b toxins were fully sequenced. The three peptides were evaluated by patch-clamp technique among Nav1.1-1.7 isoforms expressed in mammalian cell lines, and their preferential targets are Na(v)1.5>1.6>1.1. We also evaluated the role of some supposedly critical residues in the toxins which would interact with the channels, and observed that some substitutions are not critical as expected. In addition, CGTX-II and δ-AITX-Bcg1a evoke different shifts in activation/inactivation Boltzmann curves in Nav1.1 and 1.6. Moreover, our results suggest that the interaction region between toxins and VGSCs is not restricted to the supposed site 3 (S3-S4 linker of domain IV), and this may be a consequence of distinct surface of contact of each peptide vs. targeted channel. Our data suggest that the contact surfaces of each peptide may be related to their surface charges, as CGTX-II is more positive than δ-AITX-Bcg1a and δ-AITX-Bcg1b. 相似文献
80.
Kopittke PM de Jonge MD Menzies NW Wang P Donner E McKenna BA Paterson D Howard DL Lombi E 《Plant physiology》2012,159(3):1149-1158
Arsenic (As) is considered to be the environmental contaminant of greatest concern due to its potential accumulation in the food chain and in humans. Using novel synchrotron-based x-ray fluorescence techniques (including sequential computed tomography), short-term solution culture studies were used to examine the spatial distribution of As in hydrated and fresh roots of cowpea (Vigna unguiculata 'Red Caloona') seedlings exposed to 4 or 20 μm arsenate [As(V)] or 4 or 20 μm arsenite. For plants exposed to As(V), the highest concentrations were observed internally at the root apex (meristem), with As also accumulating in the root border cells and at the endodermis. When exposed to arsenite, the endodermis was again a site of accumulation, although no As was observed in border cells. For As(V), subsequent transfer of seedlings to an As-free solution resulted in a decrease in tissue As concentrations, but growth did not improve. These data suggest that, under our experimental conditions, the accumulation of As causes permanent damage to the meristem. In addition, we suggest that root border cells possibly contribute to the plant's ability to tolerate excess As(V) by accumulating high levels of As and limiting its movement into the root. 相似文献