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A cryptic RNA-binding domain in the Pol region of the L-A double-stranded RNA virus Gag-Pol fusion protein. 总被引:5,自引:2,他引:3 下载免费PDF全文
The Pol region of the Gag-Pol fusion protein of the L-A double-stranded (ds) RNA virus of Saccharomyces cerevisiae has (i) a domain essential for packaging viral positive strands, (ii) consensus amino acid sequence patterns typical of RNA-dependent RNA polymerases, and (iii) two single-stranded RNA binding domains. We describe here a third single-stranded RNA binding domain (Pol residues 374 to 432), which is unique in being cryptic. Its activity is revealed only after deletion of an inhibitory region C terminal to the binding domain itself. This cryptic RNA binding domain is necessary for propagation of M1 satellite dsRNA, but it is not necessary for viral particle assembly or for packaging of viral positive-strand single-stranded RNA. The cryptic RNA binding domain includes a sequence pattern common among positive-strand single-stranded RNA and dsRNA viral RNA-dependent RNA polymerases, suggesting that it has a role in RNA polymerase activity. 相似文献
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Carles Campmajó Jordi Joan Cairó Anna Sanfeliu Esteve Martínez Salvador Alegret Francesc Gòdia 《Cytotechnology》1994,14(3):177-182
A flow injection anlytical system based on a gas diffusion membrane module for ammonia and an ammonium flow-through potentiometric detector has been set up for measurement of L-glutamine and ammonium ions in hybridoma cell cultures. The main feature of the system is that the same basic analytical concept and equipment is used in both measurements, the only difference being for the determination of L-glutamine, in which the sample flows through an immobilized glutaminase cartridge. The conditions to enable the performance of both analysis consecutively, avoiding potential interferences by unwanted deamination of other compounds in the samples, have been determined. Finally, the proposed system has been compared with reference analytical methods for batch hybridoma cell culture experiments. 相似文献
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Longitudinal patterns of dissolved organic carbon concentration and suspended bacterial density along a blackwater river 总被引:2,自引:0,他引:2
Dissolved organic carbon (DOC) is the dominant form of carbon in transport in blackwater rivers, and bacteria are the major
biological agents of its utilization. This study describes longitudinal patterns in DOC concentration and relates them to
suspended bacterial populations in the channel. Concentrations of total DOC, three molecular weight fractions, and bacterial
numbers were determined at 12 sites along the Ogeechee River in 1985–1986 and 1989 during periods of low and high discharge.
Suspended bacterial populations were compared with DOC concentrations to determine if differences in bacterial abundance were
related to longitudinal patterns of DOC concentration. Three distinct longitudinal patterns were observed: (1) The longitudinal
pattern followed by both total and intermediate molecular weight DOC concentrations was a linear function of the geographic
distance along the river. (2) During low flow conditions, there was a high degree of correspondence between patterns of bacterial
numbers and low MW DOC (< 1000 apparent MW). (3) During periods of high discharge, the proportion of high (> 10,000) and intermediate
(1000–10,000) MW fractions increased, and there was no longer a clear relationship between bacterial cells and low MW DOC. 相似文献
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Sílvia Bronsoms Josep Villanueva Francesc Canals Enrique Querol Francesc X Aviles 《European journal of biochemistry》2003,270(17):3641-3650
Protein folding can be modulated in vivo by many factors. While chaperones act as folding catalysts and show broad substrate specificity, some pro-peptides specifically facilitate the folding of the mature protein to which they are bound. Potato carboxypeptidase inhibitor (PCI), a 39-residue protein carboxypeptidase inhibitor, is synthesized in vivo as a precursor protein that includes a 27-residue N-terminal and a seven-residue C-terminal pro-regions. In this work the disulfide-coupled folding of mature PCI in vitro has been compared with that of the same protein extended with either the N-terminal pro-sequence (ProNtPCI) or both N- and C-terminal pro-sequences (ProPCI), and also with the N-terminal pro-sequence in trans (ProNt + PCI). No significant differences can be observed in the folding kinetics or efficiencies of all these molecules. In addition, in vivo folding studies in Escherichia coli have been performed using wild-type PCI and three PCI mutant forms with and without the N-terminal pro-sequence, the mutations had been previously reported to affect folding of the PCI mature form. The extent to which the 'native-like' form was secreted to the media by each construction was not affected by the presence of the N-terminal pro-sequence. These results indicate that PCI does not depend on the N-terminal pro-sequence for its folding in both, in vitro and in vivo in E. coli. However, structural analysis by spectroscopy, hydrogen exchange and limited proteolysis by mass spectrometry, indicate the capability of such N-terminal pro-sequence to fold within the precursor form. 相似文献
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Isolation and re-association of the subunits from the pro-(carboxypeptidase A)–pro-(proteinase E) binary complex from pig pancreas 下载免费PDF全文
Josep Vendrell Francesc X. Aviles Blanca San Segundo Claudi M. Cuchillo 《The Biochemical journal》1982,205(2):449-452
The component subunits of the pro-(carboxypeptidase A)–pro-(proteinase E) binary complex from pig pancreas were separated with a high recovery (80–95%) of their original potential activity. The isolated subunits and the reconstituted complex have properties similar to those of the corresponding natural species. The tryptic activation course of the pro-(carboxypeptidase A) subunit is substantially modified when bound to pro-(proteinase E), whereas the activation of pro-(proteinase E) is not dependent on this association. 相似文献
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Proteomic analysis of microvesicles from plasma of healthy donors reveals high individual variability 总被引:1,自引:0,他引:1
Bastos-Amador P Royo F Gonzalez E Conde-Vancells J Palomo-Diez L Borras FE Falcon-Perez JM 《Journal of Proteomics》2012,75(12):3574-3584
Healthy blood plasma is required for several therapeutic procedures. To maximize successful therapeutic outcomes it is critical to control the quality of blood plasma. Clearly initiatives to improve the safety of blood transfusions will have a high economical and social impact. A detailed knowledge of the composition of healthy blood plasma is essential to facilitate such improvements. Apart from free proteins, lipids and metabolites, blood plasma also contains cell-derived microvesicles, including exosomes and microparticles from several different cellular origins. In this study, we have purified microvesicles smaller than 220nm from plasma of healthy donors and performed proteomic, ultra-structural, biochemical and functional analyses. We have detected 161 microvesicle-associated proteins, including many associated with the complement and coagulation signal-transduction cascades. Several proteases and protease inhibitors associated with acute phase responses were present, indicating that these microvesicles may be involved in these processes. There was a remarkably high variability in the protein content of plasma from different donors. In addition, we report that this variability could be relevant for their interaction with cellular systems. This work provides valuable information on plasma microvesicles and a foundation to understand microvesicle biology and clinical implications. 相似文献
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Shanna Bitencourt Fernanda Mesquita Bruno Basso Júlia Schmid Gabriela Ferreira Lucas Rizzo Moises Bauer Ramon Bartrons Francesc Ventura Jose Luis Rosa Inge Mannaerts Leo Adrianus van Grunsven Jarbas Oliveira 《Cell biochemistry and biophysics》2014,68(2):387-396
Capsaicin, the active component of chili pepper, has been reported to have antiproliferative and anti-inflammatory effects on a variety of cell lines. In the current study, we aimed to investigate the effects of capsaicin during HSC activation and maintenance. Activated and freshly isolated HSCs were treated with capsaicin. Proliferation was measured by incorporation of EdU. Cell cycle arrest and apoptosis were investigated using flow cytometry. The migratory response to chemotactic stimuli was evaluated by a modified Boyden chamber assay. Activation markers and inflammatory cytokines were determined by qPCR, immunocytochemistry, and flow cytometry. Our results show that capsaicin reduces HSC proliferation, migration, and expression of profibrogenic markers of activated and primary mouse HSCs. In conclusion, the present study shows that capsaicin modulates proliferation, migration, and activation of HSC in vitro. 相似文献