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31.
海房沟异羽叶的新联合(Anomozamites haifanggouensis (Kimura et al.) comb. nov.)是辽西和内蒙古东部中侏罗统海房沟组一种特有的本内苏铁类植物.仅发现一块标本(正、反面印痕).标本上保存3枚营养羽叶,它们同几个苞片状的小叶和一些小孢子叶联合在一起,但球果的雌蕊群部分未被保存.标本被收集于内蒙古东部的宁城县山头乡道虎村附近,产于中侏罗统海房沟组.以往在辽西葫芦岛市的南票和白马石乡上三角城等地的同一层位中也曾发现过很多分散保存的苞片状小叶和相似的小孢子叶.它们最初被潘广(1983)认为是一种双子叶的半被子植物(Cycadicotis),并将小孢子叶视为"具皱纹的雌性种囊".后来,又经Kimura等(1994)详细研究,因未找到任何与被子植物有关的证据,将它们归入一个分类位置不明的形态属Pankuangia,并被描述在P. haifanggouensis种名之下.研究结果表明,本文中被研究的标本是同本内苏铁类的Anomozamites异羽叶相连,从而为这些分散保存的生殖器官的确切分类位置的确定提供了有力的证据.  相似文献   
32.
【背景】培菌白蚁是属于白蚁科的一类与鸡枞菌属真菌共生的高等白蚁,其与体内肠道微生物和体外菌圃微生物形成三维共生体系。【目的】分析培菌白蚁菌圃和粪便的微生物多样性,并与肠道微生物进行比较。【方法】通过Illumina MiSeq高通量测序方法对培菌白蚁菌圃和粪便样品进行细菌16S rRNA基因和真菌ITS测序分析。【结果】高通量测序获得培菌白蚁菌圃和粪便样品细菌和真菌的有效序列和OTU数目。5个样品细菌OTU数目在90-199之间,而真菌OTU在10-58之间,细菌的种类多样性明显大于真菌。不论是细菌还是真菌,粪便样品的OTU数目多于菌圃样品。经物种分类分析,菌圃样品主要优势细菌是变形菌门(Proteobacteria),其相对含量超过82.4%;其次是拟杆菌门(Bacteroidetes)和厚壁菌门(Firmicutes);粪便样品中优势细菌为拟杆菌门,其次是变形菌门,粪便优势菌属为别样杆菌属和营发酵单胞菌属,这与培菌白蚁肠道菌多样性组成一致。培菌白蚁菌圃和粪便样品共生真菌主要为担子菌门(Basidiomycota)和子囊菌门(Ascomycota)。菌圃优势真菌为鸡枞菌属(Termi...  相似文献   
33.
Sphondylothamnion multifidum (Huds.) Naeg., while a typical member of the Ceramiaceae in its structure and reproduction, differs in post-fertilisation details from other known genera. The sterile cells associated with the procarp system, i.e. the apical cell, the sterile cell on the supporting cell, and the sterile pericentral cell, all divide actively after fertilisation to produce branched involucral systems which surround the gonimoblast.  相似文献   
34.
A new genus,Aurantiosporium Piepenbring, Vánky & Oberwinkler (Ustilaginales), is proposed for the smut speciesUstilago subnitens Schröter & Hennings onScleria melaleuca Reichb. The soral morphology, teliospore development, the ultrastructure of the teliospore wall and teliospore germination ofAurantiosporium subnitens, studied on collections from Costa Rica, are described for the first time. The character set ofA. subnitens including intercellular teliospore development, spores in irregular groups and light coloured spore walls with numerous layers in TEM is neither known fromUstilago norCintractia nor any other smut species.Part 113 in the series Studies inHeterobasidiomycetes from the Botanical Institute, University of Tübingen.  相似文献   
35.
The species Thuris depressus Sakakibara (1975) is proposed as a syn. n. of Thuris binodosus (Goding 1926), comb. n. The distribution of the genus is expanded from Brazil and Peru to include Ecuador and Venezuela, and the immature is described based on 75 characters.  相似文献   
36.
In this and three further papers 205 yeasts and yeast states of Basidiomycetes and presumed relatives were investigated comparatively on the basis of the carbohydrate (neutral sugars) pattern of purified cell walls, urease-activity, diazonium blue B reaction on the production of extracellular amyloid compounds (EAS), fermentation of carbohydrates, and ubiquinone data. A clustering leading to the Protomyces-, the Microbotryum-, the Ustilago-, the Dacrymyces-, and the Tremella-type became apparent, especially from the qualitative and quantitative cell wall carbohydrate pattern. The different yeast types correspond well with 5S rRNA clusters known from the literature. 31 strains clustering within the Microbotryum-type comprise the phragmobasidial smut fungi of dicotyledonous hosts (Microbotryum. Sphacelotheca), the phragmobasidial Rhodosporidium- and Leucosporidium-species including some anamorph Rhodotorula-species, which lack an oxidative degradation of myo-inositol, the genera Sporobolomyces and Sporidiobolus, the Septobasidiales and some simple septate Auriculariales e.g. Agaricostilbum, Platygloea. Main characteristics of the Microbotryum-type are: 1. The absence of extracellular amyloid compounds. 2. The dominance of mannose and the presence of fucose as cell wall constituents. 3. A positive DBB-reaction and splitting of urea. Four Ustilago species parasitic on dicotyledonous hosts were transfered to Microbotryum (M. scabiosae, M. scorzonerae, M. cordae, M. vinosum) as a consequence from cell wall carbohydrate composition, production of rhodotorulic acid, and 5S rRNA sequence data from the literature. The predominance of mannose in the cell wall — otherwise only known from ascomycetous yeasts –, a type A secondary structure of 5S rRNA, a simple unifactorial mating system in all parasitic smut species suggest that the Microbotryum-type might be ancestral to the Ustilago-type. An evolution of simple (“siphonal”) holobasidia from “pseudotrichal” phragmobasidia will be discussed.  相似文献   
37.
Males developing relatively large, costly sexually selected traits may be of superior body condition compared to small-ornamented males. Thus, males developing the largest secondary sexual trait in a given environment may also be able to augment their investment into ejaculate quality, and fertilize a larger proportion of a female's eggs. We tested the prediction that the degree of expression of a condition-dependent secondary sexual trait, the male sex comb, in a Cape Tribulation (northeastern Australia) population of Drosophila bipectinata Duda, reveals male ability to fertilize eggs in the absence of sperm competition. This test permitted us also to evaluate whether pre-copulatory sexual selection and fertilization efficiency might act additively to influence male reproductive success because a previous study of the same population demonstrated a positive association between comb size and copulation probability. The results obtained indicate that, although genotypes developing smaller sex combs collectively had a significantly higher rate of insemination failure compared to larger comb genotypes, the hatch rate and the number of eggs laid by females inseminated by the two genotypic categories were not statistically different. The results fail to support the prediction that comb size reveals noncompetitive fertilization efficiency of males in this Australian population.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 406–413.  相似文献   
38.
We investigated three rare haptorid ciliates, viz., Lagynophrya gibba Kahl (1935), Enchelys lajacola nov. spec., and Spathidium implicatum Kahl (1930), using live observation, silver impregnation, morphometry, and scanning electron microscopy. Lagynophrya gibba, which was rediscovered in peatland soil from Iceland, is referred to a new genus, Kamburophrys, and a new family, Kamburophryidae, based on a unique organelle, the brush membranoid. This structure is near the dorsal brush and composed of very narrowly spaced cilia, about 5 μm long. The genus Kamburophrys has a unique combination of features, viz., an oral cone on the oral bulge, an oblique circumoral kinety, and a subapical hump carrying the three-rowed dorsal brush and the brush membranoid. The Kamburophryidae possibly belong to the order Spathidiida. Enchelys lajacola was discovered in mud from granitic rock-pools (Lajas) in Venezuela, South America. The new species is characterized by a bottle-like shape, a macronucleus with the shape of a curved strand, a heterostichad dorsal brush, and rod-shaped toxicysts. Spathidium implicatum, which was rediscovered in an ephemeral meadow puddle near Salzburg city centre, is neotypified and referred to the genus Apertospathula because it has an open circumoral kinety.  相似文献   
39.
40.
本文给出了一类种群增长模型——带有Dirac梳的广义Logistic模型,然后对该模型进行了准确的离散化,并分析了离散后模型的动力学。  相似文献   
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