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排序方式: 共有2214条查询结果,搜索用时 187 毫秒
1.
Molecular mapping of rice chromosomes   总被引:102,自引:0,他引:102  
Summary We report the construction of an RFLP genetic map of rice (Oryza sativa) chromosomes. The map is comprised of 135 loci corresponding to clones selected from a PstI genomic library. This molecular map covers 1,389 cM of the rice genome and exceeds the current classical maps by more than 20%. The map was generated from F2 segregation data (50 individuals) from a cross between an indica and javanica rice cultivar. Primary trisomics were used to assign linkage groups to each of the 12 rice chromosomes. Seventy-eight percent of the clones assayed revealed RFLPs between the two parental cultivars, indicating that rice contains a significant amount of RFLP variation. Strong correlations between size of hybridizing restriction fragments and level of polymorphism indicate that a significant proportion of the RFLPs in rice are generated by insertions/delections. This conclusion is supported by the occurrence of null alleles for some clones (presumably created by insertion or deletion events). One clone, RG229, hybridized to sequences in both the indica and javanica genomes, which have apparently transposed since the divergence of the two cultivars from their last common ancestor, providing evidence for sequence movement in rice. As a by product of this mapping project, we have discovered that rice DNA is less C-methylated than tomato or maize DNA. Our results also suggest the notion that a large fraction of the rice genome (approximately 50%) is single copy.  相似文献
2.
渗透胁迫下水稻幼苗中叶绿素降解的活性氧损伤作用   总被引:98,自引:0,他引:98  
水稻(Oryza sativa L.)幼苗在渗透胁迫下,随着胁迫强度的增加及时间的延长,Chl降解加剧,活性氧O-·2 、H2O2 及脂质过氧化产物丙二醛(MDA)含量明显增加,抗氧化剂抗坏血酸(AsA)还原型谷胱甘肽(GSH)及胡萝卜素(CAR)含量显著降低,叶绿素蛋白复合体(Chl-Pro)结合度松弛. Chl含量的降低和O-·2 、H2O2 及MDA 含量呈显著的负相关,与AsA、GSH及CAR含量的下降呈良好的正相关性.AsA、α-生育酚(VitE)及甘露醇预处理可使胁迫诱导的MDA 增多及Chl降解延缓,而Fe2+ 、H2O2 及Fenton 反应则刺激MDA 增加. Fenton 反应可加速Chl降解. 渗透胁迫下水稻幼苗Chl的降解可能主要是由O-·2 和H2O2 的代谢产物·OH氧化损伤之故  相似文献
3.
水稻化感作用及其生理生化特性的研究   总被引:97,自引:21,他引:76  
选用具有强化感作用的6个水稻品种为供体,大田稗草为受体,研究了水稻化感作用及生理生化特性,结果表明,提高水稻叶片浸提液浓度,可以相应增强对稗草生长的抑制效果,这种抑制效果与杂草的种植密度呈负相关;化感水稻叶片浸提液能显著抑制物质稗草体内超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性,从而影响其生长;苯丙氨酸氨解酶(PAL)的活性大小与酚类物质的含量吴正相关;多种酚类物质的化感作用之间可能是增效的,也可能是拮抗的。  相似文献
4.
Development and mapping of 2240 new SSR markers for rice (Oryza sativa L.).   总被引:86,自引:0,他引:86  
A total of 2414 new di-, tri- and tetra-nucleotide non-redundant SSR primer pairs, representing 2240 unique marker loci, have been developed and experimentally validated for rice (Oryza sativa L.). Duplicate primer pairs are reported for 7% (174) of the loci. The majority (92%) of primer pairs were developed in regions flanking perfect repeats > or = 24 bp in length. Using electronic PCR (e-PCR) to align primer pairs against 3284 publicly sequenced rice BAC and PAC clones (representing about 83% of the total rice genome), 65% of the SSR markers hit a BAC or PAC clone containing at least one genetically mapped marker and could be mapped by proxy. Additional information based on genetic mapping and "nearest marker" information provided the basis for locating a total of 1825 (81%) of the newly designed markers along rice chromosomes. Fifty-six SSR markers (2.8%) hit BAC clones on two or more different chromosomes and appeared to be multiple copy. The largest proportion of SSRs in this data set correspond to poly(GA) motifs (36%), followed by poly(AT) (15%) and poly(CCG) (8%) motifs. AT-rich microsatellites had the longest average repeat tracts, while GC-rich motifs were the shortest. In combination with the pool of 500 previously mapped SSR markers, this release makes available a total of 2740 experimentally confirmed SSR markers for rice, or approximately one SSR every 157 kb.  相似文献
5.
南方水稻氮素吸收与利用效率的基因型差异及评价   总被引:70,自引:0,他引:70       下载免费PDF全文
 以南方籼型水稻(Oryza sativa)品种为试验材料进行大田试验,以探讨提高水稻氮素吸收与利用效率的基因型潜力。结果表明,除早季分蘖期氮素积累量、干物质生产效率和抽穗期氮素积累量以及晚季氮素运转效率外,各基因型氮素吸收与利用效率存在显著或极显著的差异,提高水稻氮素吸收与利用效率的基因型潜力很大。基因型生育期对其氮素吸收与利用效率产生重要影响,生育期较长的基因型其氮素吸收效率、稻谷和干物质生产效率以及农艺效率较高。杂交稻氮素的生产效率、农艺效率、回收效率和收获指数较常规稻高,但二系杂交稻并没有比三系杂交稻明显提高。通过排序方式对各基因型氮素吸收与利用效率进行评价的结果表明,不同氮素吸收与利用效率指标的排序以及同一指标早晚季的排序均存在较大差异。氮素吸收与利用效率经标准化后的综合排序可对各基因型的氮素吸收与利用效率进行综合评价,吻合系数则可较好地反映各基因型早晚季氮素吸收与利用效率的排序。  相似文献
6.
Genetic and molecular dissection of quantitative traits in rice   总被引:54,自引:0,他引:54  
Recent progress in the generation of a molecular genetic map and markers for rice has made possible a new phase of mapping individual genes associated with complex traits. This type of analysis is often referred to as quantitative trait locus (QTL) analysis. Increasing numbers of QTL analyses are providing enormous amounts of information about QTLs, such as the numbers of loci involved, their chromosomal locations and gene effects. Clarification of genetic bases of complex traits has a big impact not only on fundamental research on rice plant development, but it also has practical benefits for rice breeding. In this review, we summarize recent progress of QTL analysis of several complex traits in rice. A strategy for positional cloning of genes at QTLs is also discussed.  相似文献
7.
An essential assumption underlying markerbased prediction of hybrid performance is a strong linear correlation between molecular marker heterozygosity and hybrid performance or heterosis. This study was intended to investigate the extent of the correlations between molecular marker heterozygosity and hybrid performance in crosses involving two sets of rice materials, 9 indica and 11 japonica varieties. These materials represent a broad spectrum of the cultivated rice gene pool including landraces, primitive cultivars, historically important cultivars, modern elite cultivars and parents of superior hybrids. Varieties within each set were intermated in all possible nonreciprocal pairs resulting in 36 crosses in the indica set and 55 in the japonica set. The F1s and their parents, 111 entries in total, were examined for performance of seven traits in a replicated field trial. The parents were surveyed for polymorphisms using 96 RFLP and ten SSR markers selected at regular intervals from a published molecular marker linkage map. Molecular marker genotypes of the F1 hybrids were deduced from the parental genotypes. The analysis showed that, with very few exceptions, correlations in the indica dataset were higher than in that of their japonica counterparts. Among the seven traits analyzed, plant height showed the highest correlation between heterozygosity and hybrid performance and heteorsis in both indica and japonica datasets. Correlations were low to intermediate between hybrid performance and heterozygosity (both general and specific) in yield and yield component traits in both indica and japonica sets, and also low to intermediate between specific heterozygosity and heterosis in the indica set, whereas very little correlation was detected between heterosis and heterozygosity (either general or specific) in the japonica set. In comparison to the results from our previous studies, we concluded that the relationship between molecular marker heterozygosity and heterosis is variable, depending on the genetic materials used in the study, the diversity of rice germplasms and the complexity of the genetic basis of heterosis.  相似文献
8.
A B-lectin receptor kinase gene conferring rice blast resistance   总被引:50,自引:0,他引:50  
Rice blast, caused by the fungal pathogen Magnaporthe grisea, is one of the most devastating diseases in rice worldwide. The dominant resistance gene, Pi-d2 [previously named Pi-d(t)2], present in the rice variety Digu, confers gene-for-gene resistance to the Chinese blast strain, ZB15. Pi-d2 was previously mapped close to the centromere of chromosome 6. In this study, the Pi-d2 gene was isolated by a map-based cloning strategy. Pi-d2 encodes a receptor-like kinase protein with a predicted extracellular domain of a bulb-type mannose specific binding lectin (B-lectin) and an intracellular serine-threonine kinase domain. Pi-d2 is a single-copy gene that is constitutively expressed in the rice variety Digu. Transgenic plants carrying the Pi-d2 transgene confer race-specific resistance to the M. grisea strain, ZB15. The Pi-d2 protein is plasma membrane localized. A single amino acid difference at position 441 of Pi-d2 distinguishes resistant and susceptible alleles of rice blast resistance gene Pi-d2. Because of its novel extracellular domain, Pi-d2 represents a new class of plant resistance genes.  相似文献
9.
应用70个微卫星标记分析了3个籼稻测验种和3个粳稻测验种的多态性,发现其中36个标记可以区分籼粳测验种。再以18个籼粳品种进一步筛选,找到了分布于12条染色体的21个籼粳特异性微卫星标记。在这21个标记中,20个在籼粳亚种间带型相异,其中7个在亚种内带型一致,13个在亚种内带型不一致;1个标记在12个籼稻品种和1个粳稻品种检测到相同的带型,其余11个粳稻品种具有另一种带型。微卫星标记和RFLP标记检测籼粳亚种不仅具有一致性,而且还有互补性。 Abstract:Six indica and japonica testers were assayed using 70 microsatellite markers.Thirty-six markers distinguishing indicas from japonicas were detected.By further-screening among 18 indica and japonica varieties,21 markers distributed on 12 rice chromosomes were found to be indica-japonica differentiated.No indica varieties shared same patterns with any japonica varieties at 20 marker loci,of which identical patterns were observed within subspecies at 7 loci while within-subspecies variations were observed at 13 loci.At the remaining locus,12 indica and 1 japonica varieties had the same allele,while other 11 japonica varieties had another allele.It also showed that SSLP was not only consistent,but also complementary,to RFLP for the subspecies identification.  相似文献
10.
 Ninety-four newly developed microsatellite markers were integrated into existing RFLP framework maps of four rice populations, including two doubled haploid, a recombinant inbred, and an interspecific backcross population. These simple sequence repeats (SSR) were predominantly poly(GA) motifs, targetted because of their abundance in rice. They were isolated from a previously described sheared library and a newly constructed enzyme-digested library. Differences in the average length of poly(GA) tracts were observed for clones isolated from the two libraries. The length of GA motifs averaged 21 repeat units for clones isolated from the Tsp-509-digested library, while motifs averaged 17 units for clones from the sheared library. There was no evidence of clustering of microsatellite markers near centromeres or telomeres. Mapping of the 94 newly developed markers as well as of 27 previously reported microsatellites provided genome-wide coverage of the 12 chromosomes, with an average distance of 1 SSLP (simple sequence repeat polymorphism) per 16–20 cM. Received: 13 February 1997/Accepted: 28 February 1997  相似文献
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