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1.
空间条件对几种粮食作物的同工酶和细胞学特性的影响   总被引:47,自引:0,他引:47  
搭载1987年发射的两颗返地卫星(8月5—10日和9月9—17日)的几种小麦、大麦种子,经回收后初步研究表明:(1)对发芽率的影响:空间处理的种子,其发芽率与对照无差别;(2)对茎及生育期的影响:空间处理的种子长成的幼苗比对照强壮,植株高度有些品种明显的矮于对照。生育期有不同程度延长;(3)对染色体结构的影响:花粉母细胞减数分裂观察表明搭载卫星的种子当代可诱导出比地面更多的染色体桥、落后染色体及染色体数目异于正常体细胞数目的现象。小麦品种Cocorit—71经空间处理后花粉母细胞的染色体数目异常可高达20.51%,而地面对照组其花粉母细胞基本正常(2n=28);(4)对同工酶的影响:经空间处理的小麦种子酯酶、过氧化物酶的同工酶谱带空间处理的比地面对照减少。由此可见,空间处理可诱导纯合植物种子发生变异,为农作物育种创造一个新途径。  相似文献
2.
一种快速提取真菌染色体DNA的方法   总被引:46,自引:1,他引:45       下载免费PDF全文
介绍了一种适用于多种真菌染色体DNA的快速提取方法。该方法用石英砂振荡破壁 ,快速便捷地提取真菌染色体DNA ,提取时间仅用 1~ 2h。作者应用该方法成功地提取了粗糙脉胞菌 (Neurosporacrassa)、米曲霉 (Aspergillusoryzae)、羊肚菌 (Morchellaesculcnta)、酿酒酵母 (Saccharomycescervisae)等 4种不同真菌的染色体DNA ,所提DNA片段均大于2 0kb ,可直接用于限制性内  相似文献
3.
A binary-BAC system for plant transformation with high-molecular-weight DNA   总被引:38,自引:0,他引:38  
Carol M. Hamilton 《Gene》1997,200(1-2):107-116
A binary-BAC (BIBAC) vector suitable for Agrobacterium-mediated plant transformation with high-molecular-weight DNA was constructed. A BIBAC vector is based on the bacterial artificial chromosome (BAC) library vector and is also a binary vector for Agrobacterium-mediated plant transformation. The BIBAC vector has the minimal origin region of the Escherichia coli F plasmid and the minimal origin of replication of the Agrobacterium rhizogenes Ri plasmid, and thus replicates as a single-copy plasmid in both E. coli and in A. tumefaciens. The T-DNA of the BIBAC vector can be transferred into the plant nuclear genome. As examples, a 30-kb yeast genomic DNA fragment and a 150-kb human genomic DNA fragment were inserted into the BIBAC vector; these constructs were maintained in both E. coli and A. tumefaciens. In order to increase the efficiency of transfer of unusually large BIBAC T-DNAs, helper plasmids that carry additional copies of A. tumefaciens virulence genes virG and virE were constructed. These helper plasmids are compatible with, and can be present in addition to, the BIBAC vector in the A. tumefaciens host. This report details the components of the BIBAC system, providing information essential to the general understanding and the application of this new technology.  相似文献
4.
异源四倍体鲫鲤F9~F11染色体和性腺观察   总被引:37,自引:5,他引:32  
采用肾细胞染色体制片技术,检测了异源四倍体鲫鲤F9-F11代的染色体数目及组型,结果表明:其染色体数目为4n=200,核型公式为44m 68sm 44st 44t,证明F9—F11继续保持四倍体性。观察异源四倍体鲫鲤F9—F11成熟性腺,在这3代四倍体鱼中仍然保持正常卵巢和精巢,分别形成正常二倍体卵子和二倍体精于。在自然环境下,观察了异源四倍体鲫鲤自行产卵受精井产生存活后代过程,证明该四倍体鱼群体在自然环境下能够自行繁殖传代。异源四倍体鲫鲤稳定的染色体数目和正常的性腺结构以及自然条件下的生殖传代行为,说明该异源四倍体鲫鲤已成为一个染色体数目为4n=200、遗传性状稳定的新型四倍体鱼群体,具备形成新种所需的关键因素。  相似文献
5.
Deficiency of the wheat waxy (Wx) proteins (Wx-A1, Wx-B1 and Wx-D1) was studied in 1,960 cultivars derived from several countries. Gel electrophoretic analyses revealed that the null allele for the Wx-A1 protein occurred frequently in Korean, Japanese and Turkish wheats but was relatively rare in cultivars from other countries and regions. About 48% of the wheats deficient for the Wx-B1 protein were from Australia and India. One Chinese cultivar lacked the WxD1 protein. While 9 Japanese cultivars were deficient in both the Wx-A1 and Wx-B1 proteins, no cultivars lacked both the Wx-A1 and Wx-D1 proteins, both the Wx-B1 and Wx-D1 proteins or all three Wx proteins. Two-dimensional gel electrophoresis revealed polymorphisms of the three Wx proteins that varied according to isoelectric points or molecular weight. The Wx-A1 gene coding the Wx-A1 protein and the Wx-B1 gene coding the Wx-B1 protein were localized in the distal regions of chromosome arms 7AS and 4AL, respectively, by deletion mapping using the deletion lines developed in the common wheat cultivar Chinese Spring.  相似文献
6.
A DNA test to sex most birds   总被引:35,自引:0,他引:35  
Birds are difficult to sex. Nestlings rarely show sex-linked morphology and we estimate that adult females appear identical to males in over 50% of the world's bird species. This problem can hinder both evolutionary studies and human-assisted breeding of birds. DNA-based sex identification provides a solution. We describe a test based on two conserved CHD (chromo-helicase-DNA-binding) genes that are located on the avian sex chromosomes of all birds, with the possible exception of the ratites (ostriches, etc.; Struthioniformes). The CHD-W gene is located on the W chromosome; therefore it is unique to females. The other gene, CHD-Z, is found on the Z chromosome and therefore occurs in both sexes (female, ZW; male, ZZ). The test employs PCR with a single set of primers. It amplifies homologous sections of both genes and incorporates introns whose lengths usually differ. When examined on a gel there is a single CHD-Z band in males but females have a second, distinctive CHD-W band.  相似文献
7.
We recently identified a novel metastasis suppressor gene, BRMS1, in breast cancer. Since the BRMS1 gene maps to chromosome 11q13.1-q13.2 and since chromosome 11q defects have been described in various stages of human melanoma progression, we hypothesized that BRMS1 may function as a tumor or metastasis suppressor in melanomas as well. Quantitative real-time RT-PCR revealed that BRMS1 mRNA expression was high in melanocytes, considerably reduced in early melanoma-derived cell lines, and barely detectable in advanced/metastatic cell lines. Stable transfectants of BRMS1 in the human melanoma cell lines MelJuSo and C8161.9 did not alter the tumorigenicity of either cell line, but significantly suppressed metastasis compared to vector-only transfectants. Orthotopic tumors continued to express BRMS1, but expression was lost in lung metastases. In vitro morphology, growth rate, and histology of BRMS1 transfectants were similar to controls. BRMS1 transfectants were less invasive in a collagen sandwich assay and had restored homotypic gap junctional intercellular communication (GJIC). Thus, BRMS1 functions as a metastasis suppressor in more than one tumor type (i.e., breast carcinoma and cutaneous melanoma) by modifying several metastasis-associated phenotypes.  相似文献
8.
Genetic and epigenetic interactions in allopolyploid plants   总被引:34,自引:0,他引:34  
Allopolyploid plants are hybrids that contain two copies of the genome from each parent. Whereas wild and cultivated allopolyploids are well adapted, man-made allopolyploids are typically unstable, displaying homeotic transformation and lethality as well as chromosomal rearrangements and changes in the number and distribution of repeated DNA sequences within heterochromatin. Large increases in the length of some chromosomes has been documented in allopolyploid hybrids and could be caused by the activation of dormant retrotransposons, as shown to be the case in marsupial hybrids. Synthetic (man-made) allotetraploids of Arabidopsis exhibit rapid changes in gene regulation, including gene silencing. These regulatory abnormalities could derive from ploidy changes and/or incompatible interactions between parental genomes, although comparison of auto- and allopolyploids suggests that intergenomic incompatibilities play the major role. Models to explain intergenomic incompatibilities incorporate both genetic and epigenetic mechanisms. In one model, the activation of heterochromatic transposons (McClintock's genomic shock) may lead to widespread perturbation of gene expression, perhaps by a silencing interaction between activated transposons and euchromatic genes. Qualitatively similar responses, of lesser intensity, may occur in intraspecific hybrids. Therefore, insight into genome function gained from the study of allopolyploidy may be applicable to hybrids of any type and may even elucidate positive interactions, such as those responsible for hybrid vigor.  相似文献
9.
本文研究结果表明,亚硫酸氢钠(二氧化硫)能够引起人血淋巴细胞姊妹染色单体互换(SCE)和微核(MN)率的增加,可使淋巴细胞有丝分裂周期延迟及细胞分裂指数下降,且这些作用有显著的剂量效应关系。结果指出,亚硫酸氢钠在低浓度下仅引起细胞染色单体型畸变,在高浓度下既可引起染色单体型畸变,又可引起染色体型畸变。结果还指出,亚硫酸氢钠对染色体畸变(CA)和MN的诱发效应有明显的个体差异。硫酸钠未能引起上述细胞  相似文献
10.
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