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991.
Mecklenburg KL 《Molecular genetics and genomics : MGG》2007,277(5):481-489
The function of conserved novel human genes can be efficiently addressed in genetic model organisms. From a collection of
genes expressed in the Drosophila visual system, cDNAs expressed in vertebrates were identified and one similar to a novel human gene was chosen for further
investigation. The results reported here characterize the Drosophila retinophilin gene and demonstrate that a similar gene is expressed in the human retina. The Drosophila and human retinophilin sequences are 50% identical, and they share an additional 16% conserved substitutions. Examination
of the cDNA and genomic sequence indicates that it corresponds to the gene CG10233 of the annotated genome and predicts a
22.7 kDa protein. Polyclonal antibodies generated to a predicted retinophilin peptide recognize an antigen in Drosophila photoreceptor cells. The retinophilins encode 4 copies of a repeat associated with a Membrane Occupation and Recognition
Nexus (MORN) function first discovered in junctophilins, which may interact with the plasma membrane. These results therefore
show that Drosophila retinophilin is expressed in fly photoreceptor cells, demonstrate that a conserved human gene is expressed in human retina,
and suggest that a mutational analysis of the Drosophila gene would be valuable. 相似文献
992.
We propose a new elastic constitutive law for arterial tissue in which the limiting polymeric chain extensibility of both collagen and elastin fibres is accounted for. The elastic strain-energy function is separated additively into two parts: an isotropic contribution associated with the matrix (incorporating the elastin fibre network) and an anisotropic one associated with the collagen fibres. Information on the limiting extensibility in each case provides some mesoscopic input into the model. The (logarithm-based) model is compared with the Fung-Demiray exponential model and certain other recently proposed models. Some aspects of the elastic response under extension and inflation of a thin-walled circular cylindrical tube (the artery) are then examined and compared with the corresponding response of a rubber-like tube. We point out that our model, when both isotropic and anisotropic terms are included, can be developed to accommodate changing mechanical properties associated with degradation of the elastin and collagen by considering the material constants that define the limit of chain extensibility to evolve in time. 相似文献
993.
Soncini M Vesentini S Ruffoni D Orsi M Deriu MA Redaelli A 《Biomechanics and modeling in mechanobiology》2007,6(6):399-407
Alpha-actinin is a cytoskeleton-binding protein involved in the assembly and regulation of the actin filaments. In this work
molecular dynamics method was applied to investigate the mechanical behaviour of the human skeletal muscle α-actinin. Five
configurations were unfolded at an elongation speed of 0.1 nm/ps in order to investigate the conformational changes occurring
during the extension process. Moreover, a sensitivity analysis at different velocities was performed for one of the R2–R3
spectrin-like repeat configuration extracted in order to evaluate the effect of the pulling speed on the mechanical behaviour
of the molecule. Two different behaviours were recognized with respect to the pulling speed. In particular, at speed higher
than 0.025 nm/ps a continuous rearrangement without evident force peaks was obtained, on the contrary at lower speed evident
peaks in the range 500–750 pN were detected. R3 repeat resulted more stable than R2 during mechanical unfolding, due to the
lower hydrophobic surface available to the solvent. The characterization of the R2–R3 units can be useful for the development
of cytoskeleton network models based on stiffness values obtained by analyses performed at the molecular level. 相似文献
994.
995.
Hoppen J Dietz M Warsow G Rohde R Schüller HJ 《Molecular genetics and genomics : MGG》2007,278(3):317-330
996.
Recently we reported that Catalase-1 (CAT-1) played an important role in protecting conidial viability in Neurospora crassa, and interacted with a light signal transducer, nucleoside diphosphate kinase-1 (NDK-1). To disclose the functional interaction
between CAT-1 and NDK-1 at the genetic level, we created CAT-1 and NDK-1 double mutants, cat-1;ndk-1-1 and cat-1;ndk-1-2, by crossing single mutants of cat-1
RIP
and ndk-1
P72H
previously isolated in our laboratory. The double mutant strains grew normally, but showed increased CAT-2 activity. In cat-1
RIP
, NDK activity was increased when dCDP was used as a substrate. ndk-1
P72H
, cat-1;ndk-1-1, and cat-1;ndk-1-2 were more sensitive to riboflavin than the wild type and cat-1
RIP
under strong light (100 μE m−2 s−1). The pull-down experiment suggests that His-tagged NDK-1 is bound to [32P]NADH. However, his-tagged NDK-1P72H was not bound to [32P]NADH. The double mutants showed much lower conidial viability and lost all conidial germination ability much more rapidly
than cat-1
RIP
, when they were cultured under continuous light for more than 2 weeks. These results indicate that the interaction of CAT-1
with NDK-1 plays an important role in supporting the survival of conidia under oxidative and light-induced stress including
singlet oxygen, and confirm our former conclusion that reactive oxygen species play an important role in light signal transduction
via NDK-1 at the genetic level.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
997.
998.
Eleven novel polymorphic microsatellite loci developed from a microsatellite enriched genomic library, are presented for the
Australian tree frog Litoria peronii. We screened 29 individuals from a single population and detected high levels of polymorphism for all 11 loci with the number
of alleles/locus ranging from 9 to 24. Values of expected and observed heterozygosities ranged from 0.789–0.955 and 0.207–1.00,
respectively. These microsatellite markers should prove useful in determining levels of genetic diversity, measuring gene
flow and migration, assigning individuals to their most likely population of origin, and in the assignment of paternity. 相似文献
999.
Naohisa Kanda Mutsuo Goto Hidehiro Kato Megan V. McPhee Luis A. Pastene 《Conservation Genetics》2007,8(4):853-864
Bryde’s whales (Balaenoptera brydei) differ from other typical baleen whale species because they are restricted to tropical and warm temperate waters in major
oceans, and frequent trans-equatorial movement has been suggested for the species. We tested this hypothesis by analyzing
genetic variation at 17 microsatellite loci (N = 508) and 299 bp of mitochondrial DNA (mtDNA) control region sequences (N = 472) in individuals obtained from the western North Pacific, South Pacific, and eastern Indian Ocean. Combined use of microsatellite
and mtDNA markers allowed us to distinguish between contemporary gene flow and ancestral polymorphism and to describe sex-specific
philopatry. A high level of genetic diversity was found within the samples. Both nuclear and mtDNA markers displayed similar
population structure, indicating a lack of sex-specific philopatry. Spatial structuring was detected using both frequency-based
population parameters and individual-based Bayesian approaches. Whales in the samples from different oceanic regions came
from genetically distinct populations with evidence of limited gene flow. We observed low mtDNA sequence divergence among
populations and a lack of concordance between geographic and phylogenetic position of mtDNA haplotypes, suggesting recent
separation of populations rather than frequent trans-equatorial and inter-oceanic movement. We conclude that current gene
flow between Bryde’s whale populations is low and that effective management actions should treat them as separate entities
to ensure continued existence of the species. 相似文献
1000.
Various approaches have been developed to define conservation units for plant and animal species. In this study we combined
nuclear microsatellites (from a previous published study) and chloroplast microsatellites (assessed in the present study),
leaf and seed morphology traits and abiotic variables (climate and soil) to define evolutionary significant units (ESU) of
Santalum austrocaledonicum, a tree species growing in New Caledonia. Results for chloroplast microsatellites showed that the total population heterozygosity
was␣high, (H
cp = 0.84) but varied between islands. Differentiation was strong in the total population (F
stcp = 0.66) but also within the main island Grande Terre (F
stcp = 0.73) and within Iles Loyauté (F
stcp = 0.52), highlighting a limited gene flow between populations. These results confirmed those obtained with nuclear microsatellites.
The cluster analysis on molecular markers discriminated two main groups constituted by the populations of Grande Terre and
the populations of Iles Loyauté. A principal component analysis of leaf and seed morphology traits singled out the populations
of Iles Loyauté and the western populations of Grande Terre. Quantitative genetic analyses showed that the variation between
populations was under genetic control (broad sense heritability close to 80%). A high correlation between rainfall and morphological
traits suggested an impact of climate on this variation. The integration of these results allows to define two ESUs, one corresponding
to Grande Terre and Ile des Pins and the other the Iles Loyauté archipelago. This study stresses the need to restore some
populations of Grande Terre that are currently threatened by their small size. 相似文献