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931.
Hall GS 《Mycopathologia》1997,140(3):141-147
Using the mitochondrial DNA miniprep technique, the identity of sixteen morphologically unusual cultures allocated to Phytophthora
nicotianae, Phytophthora mexicana or Phytophthora porri was determined by comparison with a library of mtDNA band patterns
obtained from reference cultures. Seven cultures were identified as Phytophthora nicotianae (including those assigned to Phytophthora
mexicana and Phytophthora porri), six as strains of Phytophthora palmivora with small, ovoid, weakly caducous sporangia, and
one as Phytophthora citrophthora. Some cultures of P. nicotianae had a low percentage of caducous sporangia. Percentage sporangium
caducity, but not sporangium L : B ratio, is considered a useful taxonomic criterion for separating species morphologically
similar to Phytophthora nicotianae. One culture from tobacco in New Zealand had a highly unusual morphology and a unique DNA
band pattern, but was not identifiable. One culture from Acacia mearnsii in South Africa had a unique DNA band pattern which
was identical to that of an isolate from Annona squamosa from Australia previously identified as Phytophthora palmivora, the
precise identity of which is still unclear. The identity of most isolates from diseased durian was found to be Phytophthora
palmivora, confirming its role as the main pathogen, but P. nicotianae was also identified from this host.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
932.
对水稻第9和第12染色体编号分歧的细胞学考证 总被引:1,自引:1,他引:0
在水稻细胞遗传研究中, 对于染色体编号有着较多的争议,这在几条长度较短的染色体上显得尤为突出。为有比较地研究这几条染色体在水稻染色体组中的正确编号,本研究以涉及两条较短染色体相互易位的易位杂合体RT9-12为材料,分析了易位系与普通品种日本晴减数分裂粗线期染色体的形态特征。结果表明,该易位系的易位染色体并非第9和第12染色体,而是第10和第11染色体,从而认为目前国际上统一编号的第9、12染色体,根据染色体的实际长度可能分别为第10、11染色体。
Abstract:Rice chromosomes in mitosis are usually too small to be identified clearly one from others.In recent years,pachytene chromosomes in meiosis have been in vestigated intensively for establishing unified numbering system.However,divergence in numbering system is still existing especially for some short chromosomes such as chromosome 9 and 12.In order to verify these chromosomes,a translocation line RT9-12 and a japonica variety Nipponbare were carefully investigated for all the chromosomes morphologically in late pachytene stage.It was found that the chromosomes involved in translocation were chromosome 10 and 11 in stead of chromosome 9 and 12 as being compared with the karyotype of Nipponbare.So we consider that the chromosome 9 and 12 in the present rice chromosome numbering system could be chromosome 10 and 11 according to their length,arm ratio and the relationship with nucleolus. 相似文献
933.
934.
在调查陕西、甘肃两省禾谷类三种病毒病:小麦线条花叶病毒病、小麦丛矮病毒病和玉米粗病毒病的发生危害基础上,采用超薄切片和电镜技术对发生在上述两省内的三种病毒进行了病毒粒子的直接观察。 相似文献
935.
新石器时代人骨遗骸中古代DNA的提取及X—Y染色体同源基因片段的PCR扩增 总被引:1,自引:1,他引:0
从中国新石器时代人骨遗骸中提取出古代DNA。通过聚合酶链式反应技术扩增得到X-Y染色体上的单考贝同源基因片段。由于扩增的基因片段长度具有性别多态性,从而为古代人骨和牙齿提供了分子生物学的性别鉴定。 相似文献
936.
A rapid and reproducible method has been developed for genomic fingerprinting of rhizobia and other soil microbes interacting with plants. The method is based on the use of oligonucleotide primers, corresponding to conserved motifs in naturally occurring interspersed repetitive DNA elements in bacteria (rep-elements), and the polymerase chain reaction (rep-PCR). Rep-PCR results in the amplification of inter-element genomic DNA fragments of characteristic lengths and thereby generates a genomic fingerprint. These fingerprints resemble UPC bar code patterns, and can be used to identify bacteria at the sub-species and strain level, as well as for phylogenetic analyses. Here we show that highly characteristic and very reproducible rep-PCR generated genomic fingerprints can be obtained not only from purified genomic DNA, but also directly from rhizobial cells derived from liquid cultures or from colonies on plates, as well as from nodule tissue. We examine the effect of growth phase of the bacterial cells, serial subculturing and other parameters on the reproducibility of the rep-PCR fingerprinting protocol. Moreover, we describe the results of mixing experiments designed to determine if individual genomic fingerprints can be recognized in mixtures of strains. Lastly, we review the use of computer-based fragment detection and phylogentic analysis packages to analyse rep-PCR generated genomic fingerprints of a collection of Rhizobium loti and Bradyrhizobium strains nodulating different Lotus spp.The authors are with the NSF Center for Microbial Ecology and the MSU-DOE Plant Research Laboratory. F. J. de Bruijn is also with the Microbiology Department and Genetics Program of Michigan State University, E. Lansing, MI 48824 USA. 相似文献
937.
Xiao-gang Hou Yoshiaki Kawamura Ferdousi Sultana Kenji Hirose Masaki Miyake Yoshihito Otsuka Shigeki Misawa Toyoko Oguri Hiroyuki Yamamoto Takayuki Ezaki 《Microbiology and immunology》1997,41(6):453-460
16S rRNA gene-targeted probes were designed for the identification of corynebacteria at the genus and species levels. The genus-specific probe hybridized all clinically important members of the genus Corynebacterium and could distinguish them from other coryneform bacteria and phylogenetically related high G + C% gram-positive bacteria, including Actinomyces, Rhodococcus, Gordona, Nocardia, Streptomyces, Brevibacterium and Mycobacterium. The species-specific probes for C. jeikeium and C. diphtheriae could differentiate these two species from other members of this genus. The probes were used to select corynebacteria among gram-positive clinical isolates which had been tentatively identified as corynebacteria by biochemical tests. We screened 59 strains with the genus-specific probe; 51 strains hybridized to the genus-specific probe, 8 did not. Of the 51 strains that hybridized to the genus-specific probe, 1 hybridized to the C. diphtheriae species probe and 13 hybridized to the C. jeikeium species probe. The 8 strains that did not hybridize to the genus probe were further characterized by analyzing cell wall diaminopimelic acid and partial 16S rRNA sequencing. The results indicated that these strains were distributed in the genera Arthrobacter and Brevibacterium. 相似文献
938.
Eleven of 34 sturgeons caught in the River Volga classified morphologically as Acipenser gueldenstaedtii were identified as Acipenser baerii from sequence analysis of the mitochondrial cytochrome- b gene. The Caspian Sea and its tributaries including the Volga are not native habitats of A. baerii . No A. baerii haplotype was observed in A. gueldenstaedtii from the Sea of Azov or the South Caspian Sea. Genetic contamination of A. gueldenstaedtii with A. baerii or A. baerii hybrids has occurred in the Volga. Crosses and backcrosses of these specimens with native A. gueldenstaedtii resulted in the loss of the morphological diagnostic A. baerii features. These findings are of special concern for conservation and management programmes, as well as for specimen identification for caviar trading control. 相似文献
939.
Ki Wan Nam Christine A. Maggs Lynne McIvor Michael J. Stanhope 《Journal of phycology》2000,36(4):759-772
Two species of Osmundea Stackhouse (Rhodomelaceae, Rhodophyta) that occur in Atlantic Europe have been confused under the names Osmundea ramosissima (Oeder) Athanasiadis and Osmundea truncata (Kützing) Nam et Maggs, regarded until now as a synonym of O. ramosissima. An epitype from its type locality (Stavanger, Norway) is selected for Osmundea ramosissima Athanasiadis, recognized here as a valid name for Fucus ramosissimus Oeder, nom. illeg. Details of vegetative and reproductive morphology of O. ramosissima are reported, based on material from France, the British Isles, and Helgoland. Osmundea ramosissima resembles other species of Osmundea in its vegetative axial segments with two pericentral cells and one trichoblast, spermatangial development from apical and epidermal cells (filament type), the formation of five pericentral cells in the procarp‐bearing segment of the female trichoblast, and tetrasporangial production from random epidermal cells. Among the species of Osmundea, O. ramosissima is most similar to O. truncata. Both species have discoid holdfasts, secondary pit connections between epidermal cells, and cup‐shaped spermatangial pits. They differ in that: (a) O. ramosissima lacks lenticular wall thickenings and refractive needle‐like inclusions in medullary cells, both of which are present in O. truncata; (b) O. ramosissima has branched spermatangial filaments that terminate in a cluster of several cells, whereas in O. truncata the unbranched spermatangial filaments have a single large terminal sterile cell; and (c) cystocarps of O. ramosissima lack protuberant ostioles but ostioles are remarkably protuberant in O. truncata. Phylogenetic analyses of rbcL sequences of Laurencia obtusa (Hudson) Lamouroux and all five Atlantic European species of Osmundea, including the type species, strongly support the generic status of Osmundea. Osmundea ramosissima and O. truncata are closely related (5.2% sequence divergence) and form a well‐supported clade sister to a clade consisting of O. pinnatifida (Hudson) Stackhouse, O. osmunda Stackhouse and O. hybrida (A. P. de Candolle) Nam. The formation of secondary pit connections between epidermal cells is a synapomorphy for the O. ramosissima+O. truncata clade. The close relationship between species with cup‐shaped spermatangial pits (Osmundea hybrida) and urn‐shaped pits (Osmundea pinnatifida and Osmundea osmunda) shows that spermatangial pit shape is not an important phylogenetic character. Parsimony analysis of a morphological data set also supports the genus Osmundea but conflicts with the molecular trees in infrageneric relationships, placing O. hybrida basal within the Osmundea clade and grouping O. osmunda and O. pinnatifida but not O. truncata and O. ramosissima. A key to Osmundea species is presented. 相似文献
940.
J. R. Alvarado Bremer†‡ M. G. Frisk§ T. J. Miller§ J. Turner J. Viñas K. Kwil 《Journal of fish biology》2005,66(4):1177-1182
As the morphological discrimination of winter skate Leucoraja ocellata and little skate Leucoraja erinacea juveniles is unreliable, a genetic assay, based on the restriction digest with Sty I of a segment of mitochondrial DNA cytochrome oxidase I gene, capable of discriminating the species was developed. The reliable identification of species can be used to improve the accuracy of population assessment models. 相似文献