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1.
长期以来,螨类主要依靠其形态特征进行系统学研究。DNA标记是指能反映生物个体或物种间基因组中某种差异特征的DNA片段。近年来,DNA标记技术在螨类系统学研究中得到越来越广泛的应用。本文综述了随机扩增多态性RAPD、限制性内切酶片段长度多态性RFLP、微卫星SSR、核酸序列扩增、扩增片段长度多态性AFLP和直接扩增片段长度多态性DALP等6种DNA标记技术在螨类系统学研究中的应用现状及前景。 相似文献
2.
Assessment of genetic diversity and relationship among a collection of US sweet sorghum germplasm by SSR markers 总被引:1,自引:0,他引:1
M. L. Ali J. F. Rajewski P. S. Baenziger K. S. Gill K. M. Eskridge I. Dweikat 《Molecular breeding : new strategies in plant improvement》2008,21(4):497-509
Sweet sorghum (Sorghum bicolor L.) is a type of cultivated sorghums and has been recognized widely as potential alternative source of bio-fuel because of
its high fermentable sugar content in the stalk. A substantial variation of sugar content and related traits is known to exist
in US sweet sorghum. The objectives of the study were to assess the genetic diversity and relationship among the US sweet
sorghum cultivars and lines using SSR markers and to examine the genetic variability within sweet sorghum accessions for sugar
content. Sixty-eight sweet sorghum and four grain sorghum cultivars and lines were genotyped with 41 SSR markers that generated
132 alleles with an average of 3.22 alleles per locus. Polymorphism information content (PIC) value, a measure of gene diversity,
was 0.40 with a range of 0.03–0.87. The genetic similarity co-efficient was estimated based on the segregation of the 132
SSR alleles. Clustering analysis based on the genetic similarity (GS) grouped the 72 sorghum accessions into 10 distinct clusters.
Grouping based on clustering analysis was in good agreement with available pedigree and genetic background information. The
study has revealed the genetic relationship of cultivars with unknown parentage to those with known parentage. A number of
diverse pairs of sweet sorghum accessions were identified which were polymorphic at many SSR loci and significantly different
for sugar content as well. Information generated from this study can be used to select parents for hybrid development to maximize
the sugar content and total biomass, and development of segregating populations to map genes controlling sugar content in
sweet sorghum. 相似文献
3.
Benthic insect communities (Ephemeroptera, Plecoptera, Coleoptera, Trichoptera) were studied together with water temperature
and environmental parameters in streams between June 2000 and June 2001. The sampling area consisted of 20 sites in small
and medium-sized streams located in the lower mountainous area of Central Europe. Temperature was recorded nearly continuously
and several physicochemical and environmental variables were assessed. Macroinvertebrates were sampled both in spring and
summer. Data-sets of species abundance and occurrence were analysed using multivariate techniques and were correlated to the
thermal and environmental conditions of the streams. The temperature preferences of the species were compared to published
data-sets on their autecological characteristics. Up to 29% of the variability in the Ephemeroptera, Plecoptera, Trichoptera
and Coleoptera community was explained by summer temperature variation in the data-sets for both small and medium-sized streams.
A smaller, but significant part of the variability in species distribution was explained by conductivity, substratum type,
and the percent coverage of local riparian forest. Compared to small streams, temperature was less important for the macroinvertebrate
composition in medium-sized streams. This result is likely due to the more tolerant, eurythermic species composition in larger
streams. A total of 33 Ephemeroptera, Plecoptera, Coleoptera and Trichoptera taxa were positively correlated and 28 taxa were
negatively correlated to summer temperature patterns. The temperature preferences of taxa considered in this study were related
to species traits, such as egg dormancies and life cycle plasticity. 相似文献
4.
5.
Growth divergence – i.e. the expression of divergent growth trends of neighboring trees – has certain implications for dendrochronological research, for instance in the context of climate reconstructions but also in terms of estimating net ecosystem productivity. Thus, understanding the underlying mechanisms is essential to extend our fundamental dendroecological knowledge. In this context, the Picea genus plays an important role since several of its species were reported to exhibit growth divergence. Here, we investigate a well sampled Norway spruce (Picea abies (L.) Karst) data set for growth divergence comprising ring-width and Blue Intensity measurements from seven sites on Babia Góra Mountain, at the border between Poland and Slovakia. By means of Principal Component Gradient Analysis, inter-series correlations, and climate growth relationships, we are able to show that I) Norway spruce on Babia Góra expressed growth divergence since the 1970s, II) the definition of groups increased the strength of population signals and the stability of climate-growth relationships, and III) Blue Intensity appeared as a more robust proxy for environmental conditions. We discuss soil heterogeneity, genetics, and air pollution as possible underlying mechanisms, thereby indicating further research avenues to obtain a better understanding of growth divergence. 相似文献
6.
《Bioorganic & medicinal chemistry》2016,24(1):1-11
Four kinds of tetravalent double-headed glycoclusters [(LacNAc)4-DHGs] were designed with linkers of varying lengths consisting of alkanedioic carboxyamido groups (C6, C12, C18 and C24) between two bi-antennary LacNAc-glycosides. These glycoclusters served as high-affinity cross-linking ligands for the LacNAc-binding lectin Erythrina cristagalli agglutinin (ECA). The binding activity and cross-linking between each ligand and ECA were characterized by a hemagglutination inhibition (HI) assay, isothermal titration calorimetry (ITC), a quantitative precipitation assay and dynamic light scattering (DLS). For the precipitation assay and DLS measurement, the synthesized (LacNAc)4-DHGs were found to be capable of binding and precipitating the ECA as multivalent ligands. ITC analysis indicated the binding of (LacNAc)4-DHGs was driven by a favorable enthalpy change. Furthermore, the entropy penalty from binding (LacNAc)4-DHGs clearly decreased in a spacer length-dependent manner. The binding affinities of flexible (LacNAc)4-DHGs (C18 and C24) with long spacers were found to be more favorable than those of the clusters having short spacers (C6 and C12). These results were supported by molecular dynamics simulations with explicit water molecules for the tetravalent glycoclusters with ECA. We concluded that the subtle modification in the epitope-presenting scaffolds exerts the significant effect in the recognition efficiency involved in the LacNAc moieties by ECA. 相似文献
7.
Oxygen incorporation in the product of the reaction between YCl3 and the lithium salt of 1,3,4,6,7,8-hexahydro-2Hpyrimido[1,2-a]pyrimidine (hppH) afforded the tetrametallic cluster Y4(hpp)8Cl2(μ4-O), in which four of the guanidinate anions are involved in a previously unreported μ,η2,η2-bridging mode between two metal centres. 相似文献
8.
The aim of the present study is to clarify the taxonomic position of Teucrium euganeum Vis. vis à vis T.siculum (Rafin.) Guss. and T.scorodonia L. The study is based on an analysis of macro- and micro-morphological characters, type, and distribution of trichomes in different parts of the plant, chromosome counts, and a statistical analysis of such morphometric data. The results of the study allow one to consider the populations of the Euganean Hills (Padua, north-eastern Italy) as a sub-species of T.siculum, and, therefore, a new combination is proposed: Teucrium siculum (Rafin.) Guss. subsp. euganeum (Vis.) Tornadore, comb. et stat.nov. 相似文献
9.
Genotypic variation in seedling root architectural traits and implications for drought adaptation in wheat (Triticum aestivum L.) 总被引:1,自引:0,他引:1
Ahmad M. Manschadi Graeme L. Hammer John T. Christopher Peter deVoil 《Plant and Soil》2008,303(1-2):115-129
Root system characteristics are of fundamental importance to soil exploration and below-ground resource acquisition. Root
architectural traits determine the in situ space-filling properties of a root system or root architecture. The growth angle
of root axes is a principal component of root system architecture that has been strongly associated with acquisition efficiency
in many crop species. The aims of this study were to examine the extent of genotypic variability for the growth angle and
number of seminal roots in 27 current Australian and 3 CIMMYT wheat (Triticum aestivum L.) genotypes, and to quantify using fractal analysis the root system architecture of a subset of wheat genotypes contrasting
in drought tolerance and seminal root characteristics. The growth angle and number of seminal roots showed significant genotypic
variation among the wheat genotypes with values ranging from 36 to 56 (degrees) and 3 to 5 (plant−1), respectively. Cluster analysis of wheat genotypes based on similarity in their seminal root characteristics resulted in
four groups. The group composition reflected to some extent the genetic background and environmental adaptation of genotypes.
Wheat cultivars grown widely in the Mediterranean environments of southern and western Australia generally had wider growth
angle and lower number of seminal axes. In contrast, cultivars with superior performance on deep clay soils in the northern
cropping region, such as SeriM82, Baxter, Babax, and Dharwar Dry exhibited a narrower angle of seminal axes. The wheat genotypes
also showed significant variation in fractal dimension (D). The D values calculated for the individual segments of each root system suggested that, compared to the standard cultivar Hartog,
the drought-tolerant genotypes adapted to the northern region tended to distribute relatively more roots in the soil volume
directly underneath the plant. These findings suggest that wheat root system architecture is closely linked to the angle of
seminal root axes at the seedling stage. The implications of genotypic variation in the seminal root characteristics and fractal
dimension for specific adaptation to drought environment types are discussed with emphasis on the possible exploitation of
root architectural traits in breeding for improved wheat cultivars for water-limited environments. 相似文献
10.
Benjamin C. Blum Weiwei Lin Matthew L. Lawton Qian Liu Julian Kwan Isabella Turcinovic Ryan Hekman Pingzhao Hu Andrew Emili 《Molecular & cellular proteomics : MCP》2022,21(1):100189
Metabolism is recognized as an important driver of cancer progression and other complex diseases, but global metabolite profiling remains a challenge. Protein expression profiling is often a poor proxy since existing pathway enrichment models provide an incomplete mapping between the proteome and metabolism. To overcome these gaps, we introduce multiomic metabolic enrichment network analysis (MOMENTA), an integrative multiomic data analysis framework for more accurately deducing metabolic pathway changes from proteomics data alone in a gene set analysis context by leveraging protein interaction networks to extend annotated metabolic models. We apply MOMENTA to proteomic data from diverse cancer cell lines and human tumors to demonstrate its utility at revealing variation in metabolic pathway activity across cancer types, which we verify using independent metabolomics measurements. The novel metabolic networks we uncover in breast cancer and other tumors are linked to clinical outcomes, underscoring the pathophysiological relevance of the findings. 相似文献