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691.
ABSTRACT. The phylogenetic relationships of two sphaerocerid genera, Alloborborus Duda (1923) and Crumomyia Macquart (1835), are analysed, and their taxonomic status within the tribe Copromyzini (= Copromyza Fallén s.lat.) is clarified. Accepted here are a monotypic Alloborborus , which includes A.pallifrons (FalléAn) from northern and central Europe, and twenty-six species of the Holarctic Crumomyia. Within Crumomyia , five species-groups are recognized: pedestris group: pedestris (Meigen); annulus group: immensa (Spuler), maculipennis (Spuler), annulus (Walker), nipponica (Richards), pruinosa (Richards); notabilis group: glabifrons (Meigen), glacialis (Meigen), absoloni (Bezzi), notabilis (Collin), rohaceki sp.n., zuskai (Roháček); nitida group: nitida (Meigen); setitibialis group: setitibialis (Spuler), pilosa sp.n., nigra (Meigen), parentela (Séguy), deemingi (Hackman), pollinodorsata (Papp), subaptera (Malloch), gelida (Hackman), fimetaria (Meigen), roserii (Rondani); unplaced species: hentscheli (Duda), hungarica (Duda), promethei (Nartshuk). Apterina Macquart, Fungobia Lioy and Speomyia Bezzi are synonymized with Crumomyia , and the following nominal species are synonymized: tuxeni Collin with nigra, freyi Hackman with setitibialis , and annulipes Duda with annulus. C. pruinosa is considered distinct from annulus, and Copromyza subaptera is placed in Crumomyia. The identity of C.glacialis , the type species of Crumomyia , is clarified, and lectotypes are designated for five nominal species: rufoannulata Duda, annulipes, annulus, flavipennis Haliday and pallifrons. The cladistic relationships of the species of Crumomyia and Alloborborus are established and their phylogeny and biogeography are discussed. Keys to the species of Crumomyia and to the Holarctic genera of the Copromyzinae are provided.  相似文献   
692.
ABSTRACT Within forests susceptible to wildfire and insect infestations, land managers need to balance dead tree removal and habitat requirements for wildlife species associated with snags. We used Mahalanobis distance methods to develop predictive models of white-headed woodpecker (Picoides albolarvatus) nesting habitat in postfire ponderosa pine (Pinus ponderosa)-dominated landscapes on the Fremont-Winema National Forests in south central Oregon, USA. The 1-km radius (314 ha) surrounding 45 nest sites was open-canopied before fire and a mosaic of burn severities after wildfire. The 1-ha surrounding nests of white-headed woodpeckers had fewer live trees per hectare and more decayed and larger diameter snags than at non-nest sites. The leading cause of nest failure seemed to be predation. Habitat and abiotic features were not associated with nest survival. High daily survival rates and little variation within habitat features among nest locations suggest white-headed woodpeckers were consistently selecting high suitability habitats. Management activities that open the forest canopy and create conditions conducive to a mosaic burn pattern will probably provide suitable white-headed woodpecker nesting habitat after wildfire. When making postfire salvage logging decisions, we suggest that retention of larger, more decayed snags will provide nesting habitat in recently burned forests.  相似文献   
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Twelve species of the genus Aulacorthum Mordvilko 1914 (Sternorrhyncha: Aphididae) are recognized from the Korean Peninsula. One new species, Aulacorthum ixeridis n. sp., is described for apterous and alate viviparous females on Ixeris chinensis var. graminifolia (Ledeb.) H. C. Fu and Lactuca indica L. (Asteraceae). From the allied species, Aulacorthum nepetifolii Miyazaki 1968, Aulacorthum ixeridis n. sp. is distinguished by the relatively short ultimate rostral segment (0.83–1.07 × as long as the second segment hind tarsus), the dense spinules on head and the triangular short cauda. Host plants of the Korean Aulacorthum are reviewed and the identification key to subgenera and species is also presented.  相似文献   
697.
The cellular and subcellular distribution of 3H estradiol inthe forebrain of goldfish, platyfish, lizard, turtle, and ringdove was studied by thaw-mount autoradiography. The topographicdistribution of estrogen target cells in these non-mammalianspecies corresponds to the general pattern established earlierin our laboratory for mammals. In all non-mammalians studied,accumulations of estrogen target cells exist in preoptic-septal,central hypothalamic and thalamic areas. While allocorticaldistribution of estrogen target cells is present in the avianand reptilian species, it appears to be absent in the teleosts.Differences in brain evolution probably account for it. Thisphylogenetically delayed acquisition of telencephalic steroidtarget sites seems paralleled by an ontogenetic delay, as observedin the chick embryo: early embryonic appearance of estrogenuptake (receptors) in preoptic and central hypothalamic regionsand late appearance of estrogen receptors in the amygdala. Androgendistribution in the forebrain of the dove and lizard overlapswith the estrogen distribution with some exceptions.  相似文献   
698.
1. The effects of female size on fitness of the leaf-cutter bee Megachile apicalis Spinola (Hymenoptera: Megachilidae) were examined using artificial nesting sites in the field.
2. Although female size had no significant effect on female longevity or sex ratio of progeny, it did have a significant effect on fecundity; larger females attained greater realized fecundity than did smaller females.
3. This significant effect of female size on fecundity occurred because larger females produced cells faster than did smaller females.
4. Female size also had a significant effect on egg size; larger females laid larger eggs than did smaller females.
5. Female size had a significant effect on the size of investment in each progeny. The size of investment estimated by brood cell weight was greater for larger females than for smaller females. This pattern was largely absent, however, when the size of investment was estimated by adult progeny weight.
6. Female size had a significant effect on nest usurpation behaviour; larger females had a higher capacity to usurp nests than did smaller females.  相似文献   
699.
ABSTRACT Variance in population estimates is affected by the number of samples that are chosen to genotype when multiple samples are available during a sampling period. Using genetic data obtained from noninvasive hair-snags used to sample black bears (Ursus americanus) in the Northern Lower Peninsula of Michigan, USA, we developed a bootstrapping simulation to determine how precision of population estimates varied based on the number of samples genotyped. Improvements in precision of population estimates were not monotonic over all samples sizes available for genotyping. Estimates of cost, both financially and in terms of bias associated with increasing genotyping error and benefits in terms of greater estimate precision, will vary by species and field conditions and should be determined empirically.  相似文献   
700.
Transposable elements of the mariner family are widespread and have been found in the genome of plants, animals and insects. However, most of these elements contain multiple inactivating mutations and so far, only three naturally occurring mariner elements are known to be functional. In a previous study, a mariner‐like element called Hvmar1 was discovered in the genome of the tobacco budworm Heliothis virescens. Further analysis of the Hvmar1 nucleotide sequence revealed the presence of 30‐bp imperfect inverted terminal repeats and an intact open reading frame, which is considered to encode a functional transposase. In the present study, we show that the Hvmar1 element is active using interplasmid transposition assays in Drosophila melanogaster embryos. When injected into Drosophila embryos, the helper plasmid produced a transposase that was able to mediate transposition of the Hvmar1 element from a donor to a target plasmid. The transposition efficiency of Hvmar1 in D. melanogaster is approximately 11‐fold lower than that of the well‐known Mos1 mariner transposon. However, this efficiency is comparable to those observed previously with Mos1 in non‐Drosophila insects. We identified 10 independent interplasmid transposition events, albeit the recovery of these events was rare. In each case the Hvmar1 element transposed in a precise manner, with the characteristic TA dinucleotides being duplicated on insertion. Furthermore, two of the target sites identified have been used previously by Mos1 for insertion. The active transposition of Hvmar1 in D. melanogaster provides a basis for examining the mobility of this element in its natural host as well as a starting point for comparative studies with Mos1 and other functional mariner transposons.  相似文献   
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