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91.
The effects of shoot girdling on stomatal conductance (g
s), leaf photosynthesis (P
N), concentrations of carbohydrates, nitrogen and chlorophyll (Chl) in leaves, areal leaf mass (ALM), the diameter and length
of shoots, and bud abscission in pistachio were investigated. Girdling individual shoots at the base of the current year’s
shoot (girdle I), separating inflorescent buds on the terminal current year’s shoot from the developing fruits on the previous
year’s shoot, reduced inflorescent bud abscission by 70% in comparison to nongirdled controls. Girdle I significantly reduced
concentrations of nitrogen in leaves but increased those of nonstructural carbohydrates particularly of starch. Shoot diameter
increased by 13.1% and 26.4% at 33 and 81 days after girdling (DAG), respectively, compared to 1% and 3.4% in the control,
respectively. Both the leaf dry mass/fresh mass ratio and ALM were increased significantly by girdle I from 12 DAG. The concentrations
of Chl a, Chl b, Chl (a+b), as well as the ratio of Chl a/b, all decreased with girdle I. The greatest negative effect of girdle I was on g
s and P
N. P
N was reduced by 55% of its initial value and was 44% less than in the control leaves at 10 DAG, and fell to approximately
30% that of the control from 21 DAG. In contrast, girdling at the base of one-year-old shoots (girdle II), thus not separating
fruits from the inflorescent buds, did not significantly affect g
s or P
N. The effect of girdling on P
N and the possible factors that are involved in the reduction of photosynthesis in pistachio are discussed. 相似文献
92.
A gamma-glutamyl tripeptide containing an internally quenched fluorophore has been synthesized and shown to be a substrate for recombinant rat gamma-glutamyl hydrolase. HPLC, LC-MS, and fluorescence spectra support the conclusion that selective hydrolysis occurs at the penultimate peptide bond. Preliminary data indicate that hydrolysis of this substrate can be monitored continuously to yield steady-state kinetic data. 相似文献
93.
Chris Coward Olivier Restif Richard Dybowski Andrew J. Grant Duncan J. Maskell Pietro Mastroeni 《PLoS pathogens》2014,10(9)
Salmonella enterica infections are a significant global health issue, and development of vaccines against these bacteria requires an improved understanding of how vaccination affects the growth and spread of the bacteria within the host. We have combined in vivo tracking of molecularly tagged bacterial subpopulations with mathematical modelling to gain a novel insight into how different classes of vaccines and branches of the immune response protect against secondary Salmonella enterica infections of the mouse. We have found that a live Salmonella vaccine significantly reduced bacteraemia during a secondary challenge and restrained inter-organ spread of the bacteria in the systemic organs. Further, fitting mechanistic models to the data indicated that live vaccine immunisation enhanced both the bacterial killing in the very early stages of the infection and bacteriostatic control over the first day post-challenge. T-cell immunity induced by this vaccine is not necessary for the enhanced bacteriostasis but is required for subsequent bactericidal clearance of Salmonella in the blood and tissues. Conversely, a non-living vaccine while able to enhance initial blood clearance and killing of virulent secondary challenge bacteria, was unable to alter the subsequent bacterial growth rate in the systemic organs, did not prevent the resurgence of extensive bacteraemia and failed to control the spread of the bacteria in the body. 相似文献
94.
95.
We employed a genetic approach to study protein glycosylation in the
procyclic form of the parasite Trypanosoma brucei. Two different mutant
parasites, ConA 1-1 and ConA 4-1, were isolated from mutagenized cultures
by selecting cells which resisted killing or agglutination by concanavalin
A. Both mutant cells show reduced concanavalin A binding. However, the
mutants have different phenotypes, as indicated by the fact that ConA 1-1
binds to wheat germ agglutinin but ConA 4-1 and wild type do not. A blot
probed with concanavalin A revealed that many proteins in both mutants lost
the ability to bind this lectin, and the blots resembled one of wild type
membrane proteins treated with PNGase F. This finding suggested that the
mutants had altered asparagine- linked glycosylation. This conclusion was
confirmed by studies on a flagellar protein (Fla1) and procyclic acidic
repetitive protein (PARP). Structural analysis indicated that the N- glycan
of wild type PARP is exclusively Man5GlcNAc2 whereas that in both mutants
is predominantly a hybrid type with a terminal N- acetyllactosamine. The
occupancy of the PARP glycosylation site in ConA 4-1 was much lower than
that in ConA 1-1. These mutants will be useful for studying trypanosome
glycosylation mechanisms and function.
相似文献
96.
97.
98.
Coward JL 《Journal of biological physics》2010,36(4):405-425
As there are no published graphically presented, detailed IR spectra of nonacosan-10-ol (occurring naturally and widely in
plant epicuticular waxes of nanotube form), near IR FTIR spectroscopy (fundamentals, overtones and combinations) has been
performed on laboratory synthesized racemic nonacosan-10-ol, as a crystalline solid on Mylar and polypropylene substrates.
Room temperature, in vacuo data are presented graphically, in full, and show evidence of extensive hydrogen bonding, an orthorhombic perpendicular subcell,
a methylene wagging progression, diagnostic of all-trans conformational order, and Fermi resonance. Moderate or stronger anharmonicity is confirmed. Detailed discussion, quantitative
in parts, is given of the observed spectral features, especially as to how they inform crystal structure and molecular conformation,
and assignments given for some of the features. The results will serve as a reference for future IR studies of the natural
epicuticular wax nanotube form of (S)-nonacosan-10-ol. 相似文献
99.
Coward C Grant AJ Swift C Philp J Towler R Heydarian M Frost JA Maskell DJ 《Applied and environmental microbiology》2006,72(7):4638-4647
This study characterizes the interaction between Campylobacter jejuni and the 16 phages used in the United Kingdom typing scheme by screening spontaneous mutants of the phage-type strains and transposon mutants of the sequenced strain NCTC 11168. We show that the 16 typing phages fall into four groups based on their patterns of activity against spontaneous mutants. Screens of transposon and defined mutants indicate that the phage-bacterium interaction for one of these groups appears to involve the capsular polysaccharide (CPS), while two of the other three groups consist of flagellatropic phages. The expression of CPS and flagella is potentially phase variable in C. jejuni, and the implications of these findings for typing and intervention strategies are discussed. 相似文献
100.
MOTIVATION: Repeat sequences in ESTs are a source of problems, in particular for clustering. ESTs are therefore commonly masked against a library of known repeats. High quality repeat libraries are available for the widely studied organisms, but for most other organisms the lack of such libraries is likely to compromise the quality of EST analysis. RESULTS: We present a fast, flexible and library-less method for masking repeats in EST sequences, based on match statistics within the EST collection. The method is not linked to a particular clustering algorithm. Extensive testing on datasets using different clustering methods and a genomic mapping as reference shows that this method gives results that are better than or as good as those obtained using RepeatMasker with a repeat library. AVAILABILITY: The implementation of RBR is available under the terms of the GPL from http://www.ii.uib.no/~ketil/bioinformatics CONTACT: ketil.malde@bccs.uib.no SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online. 相似文献