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81.
82.
Two geographically distinct strains of Microtus oeconomus, each consisting of an inbred (sibling mating) and an outbred treatment group, were bred in the laboratory over three generations to determine the effects of inbreeding on reproductive parameters, growth rates of young and paternal behavior The southern strain (orginating from southern Norway) suffered from depressed reproductive rate (litter size and pregnancy rates) most likely due to inbreeding, while no effects of inbreeding were detected m the northern strain (originating from northern Norway) This result questions previous generalizations about inbreeding tolerance at the species level for Microtus Growth rates and paternal behavior did not differ significantly between inbred and outbred voles in either strain Inbreeding depression rather than inbreeding avoidance is the most likely mechanism behind the depression in reproductive parameters of inbred southern voles This is suggested by the decrease in the proportion of breeding pairs with the number of generations of inbreeding, and by the reduced litter size of inbred compared with outbred pairs Field and laboratory studies have shown that behavioral and demographic traits, possibly related to the degree of inbreeding, differ between the two strains which suggests that inbreeding tolerance might be a life history adaptation 相似文献
83.
Martin Alcala Jr. Kim D. JonesJianhong Ren Thomas E. Andreassen 《Bioresource technology》2009,100(17):3991-3996
Compost based material has been proposed for use as media for biofiltration for environmental restoration in many areas to remediate contaminated water and soil. The objective of this project was to develop techniques to produce compost products for nitrate removal in storm water biofiltration applications, from typical solid waste materials. Compost products were manufactured from different feedstocks and evaluated for their nitrate removal efficiencies. Three different compost products manufactured from varying feedstock amounts of wood chips and grass clippings, along with some dry compost material from the City of Brownsville Municipal Landfill Facility (BMLF), were evaluated using column studies. Indicators of the compost product’s quality included moisture % content, pH, and conductivity measurements. The columns were loaded with water containing at least 13.5 mg/L nitrate–nitrogen and effluent water from the columns was tested to determine the nitrate reduction for the different products. All of the manufactured compost products and the BMLF material removed some nitrate. The project demonstrated that compost product materials can be effectively used for some nitrate removal for surface water quality improvement and that compost product feedstocks and blends can influence the materials capability for nitrate removal. 相似文献
84.
Lars Borre Thorvald F. Andreassen Lei Shi Harel Weinstein Ulrik Gether 《The Journal of biological chemistry》2014,289(37):25764-25773
The dopamine transporter (DAT) belongs to the family of neurotransmitter:sodium symporters and controls dopamine (DA) homeostasis by mediating Na+- and Cl−-dependent reuptake of DA. Here we used two-electrode voltage clamp measurements in Xenopus oocytes together with targeted mutagenesis to investigate the mechanistic relationship between DAT ion binding sites and transporter conductances. In Li+, DAT displayed a cocaine-sensitive cation leak current ∼10-fold larger than the substrate-induced current in Na+. Mutation of Na+ coordinating residues in the first (Na1) and second (Na2) binding sites suggested that the Li+ leak depends on Li+ interaction with Na2 rather than Na1. DA caused a marked inhibition of the Li+ leak, consistent with the ability of the substrate to interact with the Li+-occupied state of the transporter. The leak current in Li+ was also potently inhibited by low millimolar concentrations of Na+, which according to our mutational data conceivably depended on high affinity binding to Na1. The Li+ leak was further regulated by Cl− that most likely increases Li+ permeation by allosterically lowering Na2 affinity. Interestingly, mutational lowering of Na2 affinity by substituting Asp-420 with asparagine dramatically increased cation permeability in Na+ to a level higher than seen in Li+. In addition to reveal a functional link between the bound Cl− and the cation bound in the Na2 site, the data support a key role of Na2 in determining cation permeability of the transporter and thereby possibly in regulating the opening probability of the inner gate. 相似文献
85.
Erik Knutsen Tonje Fiskaa Anita Ursvik Tor Erik J?rgensen Maria Perander Eiliv Lund Ole Morten Seternes Steinar D. Johansen Morten Andreassen 《PloS one》2013,8(10)
MicroRNA profiling represents an important first-step in deducting individual RNA-based regulatory function in a cell, tissue, or at a specific developmental stage. Currently there are several different platforms to choose from in order to make the initial miRNA profiles. In this study we investigate recently developed digital microRNA high-throughput technologies. Four different platforms were compared including next generation SOLiD ligation sequencing and Illumina HiSeq sequencing, hybridization-based NanoString nCounter, and miRCURY locked nucleic acid RT-qPCR. For all four technologies, full microRNA profiles were generated from human cell lines that represent noninvasive and invasive tumorigenic breast cancer. This study reports the correlation between platforms, as well as a more extensive analysis of the accuracy and sensitivity of data generated when using different platforms and important consideration when verifying results by the use of additional technologies. We found all the platforms to be highly capable for microRNA analysis. Furthermore, the two NGS platforms and RT-qPCR all have equally high sensitivity, and the fold change accuracy is independent of individual miRNA concentration for NGS and RT-qPCR. Based on these findings we propose new guidelines and considerations when performing microRNA profiling. 相似文献
86.
Rémy A Le Galliard JF Gundersen G Steen H Andreassen HP 《The Journal of animal ecology》2011,80(5):929-937
1. Individuals should benefit from settling in high-quality habitats, but dispersers born under favourable conditions have a better physical condition and should therefore be more successful at settling in high-quality habitats. 2. We tested these predictions with root voles (Microtus oeconomus) by a manipulation of individual condition through litter-size enlargement and reduction during lactation combined with a manipulation of habitat quality through degradation of the vegetation cover. We accurately monitored movements of 149 juveniles during a settlement and breeding period of 3 months. 3. The litter size treatment had long-lasting effects on body size, life-history traits and home range size, but did not influence dispersal behaviour. 4. Different stages of dispersal were influenced by habitat quality. In low-quality patches, females dispersed earlier, spent more time prospecting their environment before settling, and settlers had a smaller adult body size than in high-quality patches. Preference and competition for high-quality patches is likely adaptive as it increased fitness both in terms of survival and reproduction. 5. We found no interactive effect of individual condition and habitat quality on natal dispersal and habitat selection. 6. These findings suggest that immediate conditions are more important determinants of dispersal decisions than conditions experienced early in life. 相似文献
87.
Petter Glorvigen Ottar N. Bjørnstad Harry P. Andreassen Rolf A. Ims 《Population Ecology》2012,54(1):55-63
Despite the recognised importance of colonisation (settlement in empty habitats) and immigration (settlement in an established
population) to species persistence and evolution few have investigated these processes in territorial mammals and how they
affect species’ traits. We translocated female bank voles (Myodes glareolus) onto an island (2.58 ha) in a two-stage experiment (stage 1: colonisation of empty population space and stage 2: immigration into an established population) to test (1) if colonisers and immigrants differ in probability of settlement and pregnancy,
and (2) if settlement is affected by cues of conspecifics, i.e., simulated deserted home ranges (SDHR) and resident presence.
Density was kept well below saturation in 8 temporally distinct population replicates over 3 years. SDHR and resident presence
neither attracted nor repelled colonisers and immigrants, respectively, and settlement was not different from a random model.
Probability of settlement tended to be higher in colonisers than immigrants and the probability of pregnancy was significantly
higher in colonisers; immigrants settling within the home range of residents had nearly zero probability of pregnancy. Colonisation
of empty habitat patches selected based on physical or resource based habitat features is apparently the optimal settlement
strategy of dispersing voles, because cues from conspecifics may provide ambiguous information and social factors may inhibit
settlement or delay reproduction in immigrants even at low population density. 相似文献
88.
89.
Ersland KM Christoforou A Stansberg C Espeseth T Mattheisen M Mattingsdal M Hardarson GA Hansen T Fernandes CP Giddaluru S Breuer R Strohmaier J Djurovic S Nöthen MM Rietschel M Lundervold AJ Werge T Cichon S Andreassen OA Reinvang I Steen VM Le Hellard S 《PloS one》2012,7(2):e31687
Background
Despite its estimated high heritability, the genetic architecture leading to differences in cognitive performance remains poorly understood. Different cortical regions play important roles in normal cognitive functioning and impairment. Recently, we reported on sets of regionally enriched genes in three different cortical areas (frontomedial, temporal and occipital cortices) of the adult rat brain. It has been suggested that genes preferentially, or specifically, expressed in one region or organ reflect functional specialisation. Employing a gene-based approach to the analysis, we used the regionally enriched cortical genes to mine a genome-wide association study (GWAS) of the Norwegian Cognitive NeuroGenetics (NCNG) sample of healthy adults for association to nine psychometric tests measures. In addition, we explored GWAS data sets for the serious psychiatric disorders schizophrenia (SCZ) (n = 3 samples) and bipolar affective disorder (BP) (n = 3 samples), to which cognitive impairment is linked.Principal Findings
At the single gene level, the temporal cortex enriched gene RAR-related orphan receptor B (RORB) showed the strongest overall association, namely to a test of verbal intelligence (Vocabulary, P = 7.7E-04). We also applied gene set enrichment analysis (GSEA) to test the candidate genes, as gene sets, for enrichment of association signal in the NCNG GWAS and in GWASs of BP and of SCZ. We found that genes differentially expressed in the temporal cortex showed a significant enrichment of association signal in a test measure of non-verbal intelligence (Reasoning) in the NCNG sample.Conclusion
Our gene-based approach suggests that RORB could be involved in verbal intelligence differences, while the genes enriched in the temporal cortex might be important to intellectual functions as measured by a test of reasoning in the healthy population. These findings warrant further replication in independent samples on cognitive traits. 相似文献90.
Rogier AM Quax Jan W Koper Pascal HP de Jong Ramona van Heerebeek Angelique E Weel Anne M Huisman Derkjen van Zeben Frank H de Jong Steven WJ Lamberts Johanna MW Hazes Richard A Feelders 《Arthritis research & therapy》2012,14(4):R195