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排序方式: 共有315条查询结果,搜索用时 265 毫秒
71.
Runar Gjerp Solstad Chun Li Johan Isaksson Jostein Johansen Johan Svenson Klara Stensv?g Tor Haug 《PloS one》2016,11(3)
The global problem of microbial resistance to antibiotics has resulted in an urgent need to develop new antimicrobial agents. Natural antimicrobial peptides are considered promising candidates for drug development. Echinoderms, which rely on innate immunity factors in the defence against harmful microorganisms, are sources of novel antimicrobial peptides. This study aimed to isolate and characterise antimicrobial peptides from the Edible sea urchin Echinus esculentus. Using bioassay-guided purification and cDNA cloning, three antimicrobial peptides were characterised from the haemocytes of the sea urchin; two heterodimeric peptides and a cysteine-rich peptide. The peptides were named EeCentrocin 1 and 2 and EeStrongylocin 2, respectively, due to their apparent homology to the published centrocins and strongylocins isolated from the green sea urchin Strongylocentrotus droebachiensis. The two centrocin-like peptides EeCentrocin 1 and 2 are intramolecularly connected via a disulphide bond to form a heterodimeric structure, containing a cationic heavy chain of 30 and 32 amino acids and a light chain of 13 amino acids. Additionally, the light chain of EeCentrocin 2 seems to be N-terminally blocked by a pyroglutamic acid residue. The heavy chains of EeCentrocins 1 and 2 were synthesised and shown to be responsible for the antimicrobial activity of the natural peptides. EeStrongylocin 2 contains 6 cysteines engaged in 3 disulphide bonds. A fourth peptide (Ee4635) was also discovered but not fully characterised. Using mass spectrometric and NMR analyses, EeCentrocins 1 and 2, EeStrongylocin 2 and Ee4635 were all shown to contain post-translationally brominated Trp residues in the 6 position of the indole ring. 相似文献
72.
73.
Identification of 27-oxo-octacosanoic acid and heptacosane-1,27-dioic acid in Legionella pneumophila
Hermann Moll ers Sonesson Erik Jantzen Reinhard Marre Ulrich Zähringer 《FEMS microbiology letters》1992,97(1-2):1-6
A strain of Escherichia coli having elevated levels of cytochrome bo and lacking the cytochrome bd quinol oxidase was grown in chemostat culture at low copper levels. Such cells had lowered levels of copper and of total cytochrome b. Cytochrome o concentration was unchanged when assayed by conventional CO difference spectroscopy, but apparently diminished by 80% in copper-deficient cells as determined by photodissociation of bound CO at 193 K. This is attributed to depletion of copper in the oxidase of copper-deficient cells, causing rapid recombination of photodissociated CO to haem O. CO recombination was also more sensitive to low intensities of actinic light in copper-depleted oxidase. The results illustrate a further similarity between the active sites of o- and aa3-type terminal oxidases. 相似文献
74.
Herbert Lüers 《Molecular & general genetics : MGG》1955,87(1):93-96
Zusammenfassung Thioxanthon hat sich, in schwacher Konzentration (0,025%) oral appliziert, bei Drosophila als ein sehr schwach, aber nachweisbar wirksames Mutagen erwiesen. Seine Wirksamkeit wurde besonders an der Reaktion der unreifen Stadien der Spermatogenese nachgewiesen. Der Anteil der Chromosomenmutationen ist auffällig hoch. 相似文献
75.
Karen L Svenson Randy Von Smith Phyllis A Magnani Heather R Suetin Beverly Paigen Jürgen K Naggert Renhua Li Gary A Churchill Luanne L Peters 《Journal of applied physiology》2007,102(6):2369-2378
The breadth of genetic and phenotypic variation among inbred strains is often underappreciated because assessments include only a limited number of strains. Evaluation of a larger collection of inbred strains provides not only a greater understanding of this variation but collectively mimics much of the variation observed in human populations. We used a high-throughput phenotyping protocol to measure females and males of 43 inbred strains for body composition (weight, fat, lean tissue mass, and bone mineral density), plasma triglycerides, high-density lipoprotein and total cholesterol, glucose, insulin, and leptin levels while mice consumed a high-fat, high-cholesterol diet. Mice were fed a chow diet until they were 6-8 wk old and then fed the high-fat diet for an additional 18 wk. As expected, broad phenotypic diversity was observed among these strains. Significant variation between the sexes was also observed for most traits measured. Additionally, the response to the high-fat diet differed considerably among many strains. By the testing of such a large set of inbred strains for many traits, multiple phenotypes can be considered simultaneously and thereby aid in the selection of certain inbred strains as models for complex human diseases. These data are publicly available in the web-accessible Mouse Phenome Database (http://www.jax.org/phenome), an effort established to promote systematic characterization of biochemical and behavioral phenotypes of commonly used and genetically diverse inbred mouse strains. Data generated by this effort builds on the value of inbred mouse strains as a powerful tool for biomedical research. 相似文献
76.
The mechanistic details of mtDNA maintenance in petite-negative yeasts have remained largely unexplored. We report here that the DNA helicase Hmi1p plays a crucial role in mtDNA stability in Candida albicans. Like its counterpart in Saccharomyces cerevisiae, Hmi1p in C. albicans (CaHmi1p) contains a C-terminal mitochondrial targeting signal that is functional in both organisms. Biochemical analysis demonstrates that CaHmi1p is a protein possessing ATP-dependent 3'-5' DNA-unwinding activity. Deletion of both HMI1 alleles does not lead to complete loss of mtDNA in C. albicans; however, substantial fragmentation of the wild-type mitochondrial genome, reduction of mtDNA mass and loss of wild-type nucleoid distribution occur. Specific regions of the mitochondrial genome give rise to mtDNA molecule populations with altered characteristics upon CaHMI1 deletion. Fragmentation of the mitochondrial genome can be reversed by reintroduction of CaHmi1p. This is the first time that a gene required for wild-type mtDNA maintenance in S. cerevisiae has been demonstrated to be nonessential in a petite-negative yeast. 相似文献
77.
Cecilie L. Licht ers B. Marcussen Gregers Wegener† David H. Overstreet‡ Susana Aznar Gitte M. Knudsen 《Journal of neurochemistry》2009,109(5):1363-1374
The 5-hydroxytryptamine (5-HT4 ) receptor may be implicated in depression and is a new potential target for antidepressant treatment. We have investigated the brain 5-HT4 receptor [3 H]SB207145 binding in the Flinders Sensitive Line rat depression model by quantitative receptor autoradiography, and related this to 5-HT transporter ( S )-[ N -methyl-3 H]citalopram binding. We also determined the regulation of 5-HT4 receptor binding by 1, 14, and 21 days of paroxetine administration and subchronic 5-HT depletion, and compared this with changes in 5-HT2A receptor [3 H]MDL100907 binding. In the Flinders Sensitive Line, the 5-HT4 receptor and 5-HT transporter binding were decreased in the dorsal and ventral hippocampus, and the changes in binding were directly correlated within the dorsal hippocampus. Chronic but not acute paroxetine administration caused a 16–47% down-regulation of 5-HT4 receptor binding in all regions evaluated including the basal ganglia and hippocampus, while 5-HT depletion increased the 5-HT4 receptor binding in the dorsal hippocampus, hypothalamus, and lateral globus pallidus. In comparison, the 5-HT2A receptor binding was decreased in the frontal and cingulate cortices after chronic paroxetine administration, and markedly reduced in several regions after 5-HT depletion. Thus, the 5-HT4 receptor binding was decreased in the Flinders Sensitive Line depression model and in response to chronic paroxetine administration. 相似文献
78.
Allan E. Johnson Fredrik Jeppsson† Johan Sandell‡ David Wensbo‡ Jan A. M. Neelissen§ ers Juréus Peter Ström‡ Henrietta Norman† Lars Farde¶ Samuel P. S. Svensson† 《Journal of neurochemistry》2009,108(5):1177-1186
The presence of β‐amyloid plaques in brain is a hallmark of Alzheimer’s disease (AD) and serves as a biomarker for confirmation of diagnosis postmortem. Positron emission tomography (PET) radioligands such as Pittsburgh compound B ([11C]‐2‐(3‐fluoro‐4‐methylamino‐phenyl)‐benzothiazol‐6‐ol) (PIB) binds selectively to β‐amyloid and are promising new tools supporting the clinical diagnoses of AD. In addition, such methodology may be useful for evaluation of new drugs aiming at reduction of amyloid plaque load. The objective of this study is to develop a new amyloid selective PET radioligand with higher signal‐to‐background ratio when compared with existing amyloid PET ligands. The lead compound, AZD2184, (2‐[6‐(methylamino)pyridin‐3‐yl]‐1,3‐benzothiazol‐6‐ol) was found to have high affinity for amyloid fibrils in vitro (Kd: 8.4 ± 1.0 nM). Two minutes after i.v. administration in rats, about 1% of the dose was in brain. In vitro autoradiography on cortical brain sections from amyloid‐beta precursor protein/presenilin 1 (APP/PS1) mice and AD patients showed that while [3H]AZD2184 and [3H]PIB are mutually displaceable, [3H]AZD2184 displays a higher signal‐to‐background ratio primarily by virtue of lower background binding levels. The ratio of binding ability in prefrontal cortex (high plaque load) to subcortical white matter (background) was 4.5 for [3H]AZD2184 and 0.8 for [3H]PIB at 1 nM. In adjacent cortical sections from APP/PS1 mouse as well as from AD cortical tissue, [3H]AZD2184 and antibodies to human β‐amyloid labeled identical structures. In vivo administration of [3H]AZD2184 to APP/PS1 mice further showed that [3H]AZD2184 labels amyloid deposits with low non‐specific background binding. Taken together, the pre‐clinical profile of AZD2184 in relation to the reference ligand PIB, suggests that 11C‐labeled AZD2184 is a potential radioligand for PET‐visualization of β‐amyloid deposits in the living human brain. 相似文献
79.
80.
David W Johnson William Craig Rollin Brant Craig Mitton Larry Svenson Terry P Klassen 《Implementation science : IS》2006,1(1):1-13