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81.
A. Mukhopadhyay N. Arumugam A. K. Pradhan H. N. Murthy B. S. Yadav Y. S. Sodhi D. Pental 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(1):19-25
Oilseed crop Brassica carinata BBCC is a natural allotetraploid of diploid species B. nigra BB and B. oleracea CC. To transfer the nuclear and organelle genes in a concerted manner from an alien species, B. tournefortii TT, to B. carinata, we produced somatic hybrids with genomic configuration TCBB using B. nigra and B. oleracea stocks that carried selectable marker genes. B. tournefortii TT was sexually crossed with hygromycin-resistant B. oleracea CC. Protoplasts isolated from shoot cultures of hygromycin-resistant F1 hybrids of B. tournefortiixB. oleracea TC were fused with protoplasts of kanamycin-resistant B. nigra BB. In two different fusion experiments 80 colonies were obtained through selection on media containing both hygromycin and kanamycin. Of these, 39 colonies regenerated into plants. Analysis of 15 regenerants by random amplified polymorphic DNA (RAPD) markers showed the presence of all three genomes, thereby confirming these to be true hybrids. Restriction fragment length polymorphism (RFLP) analysis of organelle genomes with heterologous chloroplast (cp)and mitochondrial (mt) DNA probes showed that the chloroplast genome was inherited from either of the two parents while mitochondrial genomes predominantly showed novel configurations due to either rearrangements or intergenomic recombinations. We anticipate that the TCBB genomic configuration will provide a more conducive situation for recombination between the T and C genomes during meiosis than the TTCCBB or TCCBB type configurations that are usually produced for alien gene transfer. The agronomic aim of producing TCBB hybrids is to transfer mitochondrial genes conferring cytoplasmic male sterility and nuclear genes for fertility restoration from B. tournefortii to B. carinata. 相似文献
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84.
P. J. WETTSTEIN P. LAGER† L. JIN† J. STATES§ T. LAMB¶ R. CHAKRABORTY† 《Molecular ecology》1994,3(6):541-550
The tassel-eared squirrel, Sciurus aberti , includes six subspecies which occupy restrictive and apparently identical habitats in Ponderosa pine forests in the south-western United States and Mexico; the strict habitat requirement of this species is based on dietary requirements which are only fulfilled in these forests. To examine evolutionary relationships among certain subspecies of S. aberti , we obtained estimates of nucleotide diversity within subspecies as well as nucleotide divergence between subspecies using mitochondrial DNA (mtDNA) analysis. Restriction site polymorphisms were identified in samples of the four US subspecies: S. a. aberti (Abert), S. a. kaibabensis (Kaibab), S. a. ferreus (Ferreus), and S. a. chuscensis (Chuska) Fourteen mtDNA clones were resolved that were, with one exception, uniquely subspecific. Dendrograms constructed by neighbour-joining and maximum parsimony methods revealed two major assemblages: (1) an Abert/Kaibab group; and (2) a Ferreus/Chuska group. The Abert vs. Ferreus clones exhibited the greatest net nucleotide divergence, with a lineage separation estimate approximating 572 000 years ago assuming a nucleotide substitution rate of 7.15 × 10-9 /year/site. Five out of ten Chuska squirrels shared a clone with one Abert sample; the relative sizes of these two populations and their respective ranges as well as their close proximity support the proposal for relatively recent intermixing of Abert and Chuska populations resulting in what appears to be Abert → Chuska migration. Nucleotide diversity within subspecies ranked as Kaibab < Ferreus < Abert < Chuska; the relatively high diversity for the Chuska sample is based on the apparent introgression of Abert mtDNA. The relative diversity exhibited by Kaibab, Ferreus and Aberti samples corresponds to the range size of the respective subspecies. 相似文献
85.
T.D. Mashkova T.A. Akopian L.Y. Romanova S.P. Mitkevich Y.B. Yurov L.L. Kisselev I.A. Alexandrov 《Gene》1994,140(2):211-217
Two -satellite fragments specific for human chromosome 4 have been cloned and characterized. Under stringent annealing conditions, they hybridized in situ only to the pericentromeric region of chromosome 4, but under nonstringent conditions they hybridized to all chromosomes containing the sequences of -satellite suprachromosomal family 2 (viz., chromosomes 2, 4, 8, 9, 13, 14, 15, 18, 20, 21 and 22). Southern blot analysis reveals the 3.2-kb higher-order repeated unit which exists in two forms: as a single MspI fragment or a combination of the 2.6-kb and 0.6-kb MspI fragments. The two chromosome-4-specific cloned sequences appear to be different parts of this repeated unit. Taken together they constitute about 60% of its length. The primary structure of the higher-order repeated unit is characterized by a dimeric periodicity of the D1-D2 type which is usual to suprachromosomal family 2. At least in one site this regularity is disrupted by monomer deletion leading to the D2-D2 monomeric order. The most likely mechanism of this monomer excision is homologous unequal crossing-over. These sequences may serve as both cytogenetic and restriction-fragment length polymorphism (RFLP) markers for the pericentromeric region of chromosome 4. 相似文献
86.
87.
杂交水稻及其“三系”线粒体DNA的AP—PCR指纹图谱 总被引:23,自引:1,他引:22
为了研究水稻(Oryza sativa L.)细胞质雄性不育(CMS)与线粒体基因组的关系,应用AP-PCR 分析,用7 个任意单引物对6 种水稻品系线粒体DNA 进行了扩增。水稻线粒体DNA 的AP-PCR 产物可分为三种类型:(1)所有供试品系均能扩增的片段,它们代表了线粒体DNA 在进化上的保守性序列。有4 个引物检测到这类片段。(2)2 个以上水稻品系共同出现而在全部供试材料间存在差异的扩增片段,这类片段是检测水稻线粒体DNA多态性的主要来源。(3)一种细胞质类型所特有的扩增片段,从引物R2 和V5 的扩增产物中发现了这类片段,它们可能与CMS有关联。另外,WA型不育系珍汕97A 与其杂种之间在6 个引物的扩增图谱上均存在不同程度的差异,说明两者的线粒体DNA序列结构可能存在某种差别 相似文献
88.
Luigi R. Ceci Adolfo Saiardi Luisa Siculella Carla Quagliariello 《Plant molecular biology》1993,23(4):727-736
A tRNAVal (GAC) gene is located in opposite orientation 552 nucleotides (nt) down-stream of the cytochrome oxidase subunit III (coxIII) gene in sunflower mitochondria. The comparison with the homologous chloroplast DNA revealed that the tRNAVal gene is part of a 417 nucleotides DNA insertion of chloroplast origin in the mitochondrial genome. No tRNAVal is encoded in monocot mitochondrial DNA (mtDNA), whereas two tRNAVal species are coded for by potato mtDNA. The mitochondrial genomes of different plant species thus seem to encode unique sets of tRNAs and must thus be competent in importing the missing differing sets of tRNAs. 相似文献
89.
Richard D. Griner Rick G. Schnellmann 《In vitro cellular & developmental biology. Animal》1994,30(1):30-34
Summary We have previously shown that shaking the culture plates (SHAKE) of rabbit renal proximal tubule cells (RPTC) to maintain
adequate aeration increased aerobic metabolism and decreased the induction of glycolysis compared to RPTC cultured under standard
conditions (STILL). However, glycolysis in SHAKE RPTC remained elevated compared to glycolysis in proximal tubules in vivo.
In the present study the contribution of culture medium sugar composition and concentration to glycolytic metabolism was assessed
in RPTC. SHAKE and STILL RPTC cultured in 5 mM glucose contained lactate levels equivalent to the respective SHAKE and STILL RPTC cultured in standard culture medium which
contains 17.5 mM glucose. Similarly, the activity of lactate dehydrogenase was unchanged by lowering the medium glucose concentration. Substituting
5 mM galactose for 5 mM glucose in the culture medium significantly reduced the lactate content of both SHAKE and STILL RPTC but had no effect on
lactate dehydrogenase activity. Cell growth was equivalent under all culture conditions. Sensitivity to mitochondrial inhibition
was determined for each culture condition by measuring cell death after exposure to the respiratory inhibitor antimycin A.
The results showed a hierarchy of sensitivity to antimycin A (5 mM galactose SHAKE >5 mM glucose SHAKE >17.5 mM glucose SHAKE = 17.5 mM glucose STILL), which was generally inversely correlated with the level of glycolysis as measured by lactate content (17.5
mM glucose STILL >17.5 mM glucose SHAKE = 5 mM glucose SHAKE >5 mM galactose SHAKE). 相似文献
90.
Wilfried Bautsch 《Molecular biotechnology》1994,2(1):29-44
Macrorestriction mapping is often the first step toward a thorough physical and genetic characterization of a bacterial genome.
The problem of deducing the order of partially or completely digested macrorestriction fragments to yield a physical genome
map may readily be solved by applying twodimensional pulsed-field gel electrophoresis (2D-PFGE) techniques. These powerful
methods are quick and technically easy to perform; specifically, they are independent of DNA probes and should therefore be
applicable to any bacterial species irrespective of its prior genetic characterization. In this article, detailed step-by-step
protocols are given to set up, run, and evaluate 2D pulsed-field gels. Two basic methods are described: partial/complete 2D
gels of one restriction enzyme and complete/complete 2D gels of two different restriction enzymes. Other topics include preparation
of bacterial genomic DNA, screening for suitable rare-cutting restriction enzymes and determination of optimal running conditions.
Accompanied by many notes, these protocols are meant to offer the novice a sound and rapid access to these important methods. 相似文献