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101.
We have compared the basic organization of the primary olfactory centre, the antennal lobe (AL), in 4 hemipteran species representing the 2 major lineages in this order. The Homoptera were represented by the psyllid Trioza apicalis and its aphid relatives the grain aphid Sitobion avenae Fabricius and the rose-grain aphid Metopolophium dirhodum Walker, whereas the Heteroptera were represented by the pentatomid stink bug Euschistus heros Fabricius. The olfactory systems of psyllids and aphids are generally very small, with low numbers of afferents in comparison to other insect groups, and the smallest described so far belongs to T. apicalis, comprising less than 50 olfactory receptor neurons (ORNs). Originally, we tried to estimate numbers of olfactory glomeruli in the AL of T. apicalis, which in insects generally correspond closely to the number of different types of ORNs. Neither immunocytochemical staining nor anterograde staining of ORNs revealed any glomerular structures in the ALs of T. apicalis or the 2 aphids that were included for comparison. In contrast, the ALs of the pentatomid stink bug E. heros displayed numerous distinct and well-delineated glomeruli, showing that aglomerular ALs are not typical of all insects within the order Hemiptera. Glomeruli are hallmark features of olfactory lobes in many different phyla, and the absence of glomerular structures in psyllids and aphids appears to be unique in insects that depend on olfactory orientation. 相似文献
102.
Abstract. Remaining deciduous forests in the Fennoscandian boreal landscape have high ecological value, and are considered as key components of the forest landscape as well as remnants of a former natural forest type. To improve our understanding of the formation of deciduous forests, we studied past disturbance regimes and vegetation dynamics in three deciduous forests in boreal Sweden using dendro‐ecology, pollen analysis and charcoal analysis. We identified three stages in the development of the studied stands. Firstly, the coniferous period (pre 1800), a long‐lasting period characterized by frequent fires, livestock grazing and extensive agriculture during which Pinus sylvestris was dominant. Secondly, the transformation period (1800 ‐ 1900), when logging removed most pines from the sites while fire and grazing continued. At the time of the last fire, the sites lacked a local seed source of pines, resulting in a post‐fire succession dominated by deciduous species with the capacity to disperse over long distances. Thirdly, the deciduous period (1900 ‐ present), with little or no disturbance from fire, grazing or logging. Thus, the present deciduous stands have their origins in a complex interaction between changes in fire regime, extensive land use patterns and logging, contrary to earlier simplified explanations. We conclude that the complexity of historical patterns of land use, vegetation dynamics and disturbance should be acknowledged in the future when selecting areas for nature conservation and developing models for ecologically oriented forestry. 相似文献
103.
Assessing the use of genomic DNA as a predictor of the maximum absorbance wavelength of avian SWS1 opsin visual pigments 总被引:1,自引:1,他引:0
Anders Ödeen Nathan S. Hart Olle Håstad 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2009,195(2):167-173
Recently, in vitro mutation studies have made it possible to predict the wavelengths of maximum absorbance (λmax) of avian UV/violet sensitive visual pigments (SWS1) from the identity of a few key amino acid residues in the opsin gene.
Given that the absorbance spectrum of a cone’s visual pigment and of its pigmented oil droplet can be predicted from just
the λmax, it may become possible to predict the entire spectral sensitivity of a bird using genetic samples from live birds or museum
specimens. However, whilst this concept is attractive, it must be validated to assess the reliability of the predictions of
λmax from opsin amino acid sequences. In this paper, we have obtained partial sequences covering three of the known spectral tuning
sites in the SWS1 opsin and predicted λmax of all bird species for which the spectral absorbance has been measured using microspectrophotometry. Our results validate
the use of molecular data from genomic DNA to predict the gross differences in λmax between the violet- and ultraviolet-sensitive subtypes of SWS1 opsin. Additionally, we demonstrate that a bird, the bobolink
Dolichonyx oryzivorus L., can have more than one SWS1 visual pigment in its retina. 相似文献
104.
Jeff A. Graves Alice Helyar Martin Biuw Mart Jüssi Ivar Jüssi Olle Karlsson 《Conservation Genetics》2009,10(1):59-68
The growing number of grey seals in the Baltic Sea has led to a dramatic increase in interactions between seals and fisheries.
The conflict has become such a problem that hunting was introduced in Finland in 1998 and the Swedish Environment Protection
Agency recommended a cull of grey seals starting in 2001. Culling has been implemented despite the lack of data on population
structure. Low levels of migration between regions would mean that intensive culling in specific geographic areas would have
disproportionate effects on local population structure and genetic diversity. We used eight microsatellite loci and a 489 bp
section of the mtDNA control region to examine the genetic variability and differentiation between three breeding sites in
the Baltic Sea and two in the UK. We found high levels of genetic variability in all sampled Baltic groups for both the microsatellites
and the control region. There were highly significant differences in microsatellite allele frequencies between all three Baltic
breeding sites and between the Baltic sites and the UK sites. However, there were no significant differences in mtDNA control
region haplotypes between the Baltic sites. This genetic substructure of the Baltic grey seal populations should be taken
into consideration when managing the seal population to prevent the hunting regime from having an adverse effect on genetic
diversity by setting hunting quotas separately for the different subpopulations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
105.
Djerf Severinsson EA Trinks C Gréen H Abdiu A Hallbeck AL Stål O Walz TM 《Biochemical and biophysical research communications》2011,(3):563-568
The ErbB receptor family has been suggested to constitute a therapeutic target for tumor-specific treatment of malignant melanoma. Here we investigate the effect of the pan-ErbB tyrosine kinase inhibitor canertinib on cell growth and survival in human melanoma cells in vitro and in vivo. Canertinib significantly inhibited growth of cultured melanoma cells, RaH3 and RaH5, in a dose-dependent manner as determined by cell counting. Half-maximum growth inhibitory dose (IC50) was approximately 0.8 μM and by 5 μM both cell lines were completely growth-arrested within 72 h of treatment. Incubation of exponentially growing RaH3 and RaH5 with 1 μM canertinib accumulated the cells in the G1-phase of the cell cycle within 24 h of treatment without induction of apoptosis as determined by flow cytometry. Immunoblot analysis showed that 1 μM canertinib inhibited ErbB1-3 receptor phosphorylation with a concomitant decrease of Akt-, Erk1/2- and Stat3 activity in both cell lines. In contrast to the cytostatic effect observed at doses ?5 μM canertinib, higher concentrations induced apoptosis as demonstrated by the Annexin V method and Western blot analysis of PARP cleavage. Furthermore, canertinib significantly inhibited growth of RaH3 and RaH5 melanoma xenografts in nude mice. Pharmacological targeting of the ErbB receptors may prove successful in the treatment of patients with metastatic melanoma. 相似文献
106.
Over-accumulation of nuclear IGF-1 receptor in tumor cells requires elevated expression of the receptor and the SUMO-conjugating enzyme Ubc9 总被引:1,自引:0,他引:1
107.
Rudh A Rogell B Håstad O Qvarnström A 《Evolution; international journal of organic evolution》2011,65(5):1271-1282
The likelihood of speciation is assumed to increase when sexually selected traits diverge together with ecologically important traits. According to sexual selection theory, the evolution of exaggerated display behavior is driven by increased mating success, but limited by natural selection, for example, through predation. However, the evolution of aposematic coloration (i.e., an ecologically important trait) could relieve the evolution of exaggerated display behavior from the bound of predation, resulting in joint divergence in aposematic coloration and sexual display behavior between populations. We tested this idea by examining conspicuousness, using color contrasts between individuals and their native backgrounds, and sexual display of 118 males from genetically diverged populations of the Strawberry poison frog, Dendrobates pumilio. Our results show that the level of conspicuousness of the population predicts the sexual display behavior of males. Males from conspicuous populations used more exposed calling sites. We argue that changes in aposematic coloration may rapidly cause not only postmating isolation due to poorly adapted hybrids, but also premating isolation through shifts in mating behaviors. 相似文献
108.
Aurore Aubail Jonas Teilmann Rune Dietz Frank Rig��t Tero Harkonen Olle Karlsson Aqqalu Rosing-Asvid Florence Caurant 《Polar Biology》2011,34(9):1411-1420
Recent studies have shown that the complementary analysis of mercury (Hg) concentrations and stable isotopic ratios of nitrogen
(δ15N) and carbon (δ13C) can be useful for investigating the trophic influence on the Hg exposure and accumulation in marine top predators. In this
study, we propose to evaluate the interspecies variability of Hg concentrations in phocids from polar areas and to compare
Hg bioaccumulation between both hemispheres. Mercury concentrations, δ15N and δ13C were measured in fur from 85 individuals representing 7 phocidae species, a Ross seal (Ommatophoca rossii), Weddell seals (Leptonychotes weddellii), crabeater seals (Lobodon carcinophagus), harbour seals (Phoca vitulina), grey seals (Halichoerus grypus), ringed seals (Pusa hispida) and a bearded seal (Erignathus barbatus), from Greenland, Denmark and Antarctica. Our results showed a positive correlation between Hg concentrations and δ15N values among all individuals. Seals from the Northern ecosystems displayed greater Hg concentrations, δ15N and δ13C values than those from the Southern waters. Those geographical differences in Hg and stable isotopes values were likely
due to higher environmental Hg concentrations and somewhat greater number of steps in Arctic food webs. Moreover, dissimilarities
in feeding habits among species were shown through δ15N and δ13C analysis, resulting in an important interspecific variation in fur Hg concentrations. A trophic segregation was observed
between crabeater seals and the other species, resulting from the very specific diet of krill of this species and leading
to the lowest observed Hg concentrations. 相似文献
109.
Karlsson EN Hachem MA Ramchuran S Costa H Holst O Svenningsen SF Hreggvidsson GO 《FEMS microbiology letters》2004,241(2):233-242
Until recently, the function of the fifth domain of the thermostable modular xylanase Xyn10A from Rhodothermus marinus was unresolved. A putative homologue to this domain was however identified in a mannanase (Man26A) from the same microorganism which raised questions regarding a common function. An extensive search of all accessible data-bases as well as the partially sequenced genomes of R. marinus and Cytophaga hutchinsonii showed that homologues of this domain were encoded by multiple genes in microorganisms in the phylum Bacteroidetes. Moreover, the domain occurred invariably at the C-termini of proteins that were predominantly extra-cellular/cell attached. A primary structure motif of three conserved regions including structurally important glycines and a proline was also identified suggesting a conserved 3D fold. This bioinformatic evidence suggested a possible role of this domain in mediating cell attachment. To confirm this theory, R. marinus was grown, and activity assays showed that the major part of the xylanase activity was connected to whole cells. Moreover, immunocytochemical detection using a Xyn10A-specific antibody proved presence of Xyn10A on the R. marinus cell surface. In the light of this, a revision of experimental data present on both Xyn10A and Man26A was performed, and the results all indicate a cell-anchoring role of the domain, suggesting that this domain represents a novel type of module that mediates cell attachment in proteins originating from members of the phylum Bacteroidetes. 相似文献
110.
Joana F. Marques Hong-Lei Wang Glenn P. Svensson Enric Frago Olle Anderbrant 《Evolutionary ecology》2014,28(5):829-848
The brown tail moth (BTM) Euproctis chrysorrhoea (Linnaeus 1758) (Lepidoptera: Erebidae) is a forest and ornamental pest in Europe and the United States. Its extreme polyphagy, and documented phenological shift associated with host use suggest the presence of distinct host-races. To test this hypothesis, we sampled BTM infesting different host species in several locations along its distribution, and used DNA sequence data (a total of 1,672 bp from cytochrome c oxidase subunit I, elongation factor 1-alpha, and wingless) to produce haplotype networks and reconstruct the phylogenetic relationships between individuals. Population genetic diversity indices pointed out a higher genetic diversity in Europe, particularly in the samples from southern Spain and southern England. Lower F ST values were found between geographically closer populations when compared to more distant ones, but analyses of molecular variance and Mantel tests failed to reveal geographically associated genetic differentiation. However, haplotype networks and phylogenetic reconstructions revealed a previously unknown genetic differentiation within the BTM, with one lineage circumscribed to southern Europe. Although BTM haplotypes did not cluster according to their host plant, host-associated haplotypes were observed within certain geographic regions. Hence, our data support the existence of host-races of BTM within southern Spain and southern England, where populations from different hosts occur in sympatry. 相似文献