首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   41篇
  免费   2篇
  国内免费   31篇
  2019年   1篇
  2017年   2篇
  2016年   1篇
  2015年   1篇
  2014年   5篇
  2013年   2篇
  2010年   1篇
  2008年   4篇
  2007年   2篇
  2006年   3篇
  2005年   5篇
  2004年   7篇
  2003年   2篇
  2002年   7篇
  2001年   6篇
  2000年   2篇
  1999年   4篇
  1998年   1篇
  1997年   1篇
  1996年   3篇
  1995年   1篇
  1994年   3篇
  1993年   3篇
  1987年   1篇
  1985年   2篇
  1981年   1篇
  1950年   1篇
  1948年   2篇
排序方式: 共有74条查询结果,搜索用时 0 毫秒
61.
Ovarian cancer is an important gynecological tumor, with the third highest morbidity rate and highest mor-tality rate in gynecological cancers, of which the 5-year survival rate remains at only 19%―38.7%[1]. Tumors occurring in ovary can hardly be diagnosed in the early stages for the dormant start, and approxi-mately 70% patients cannot get the final diagnosis until the advanced stages. Surgical operation and post-operational chemotherapy based on cisplatin have become the primary treatment …  相似文献   
62.
报道了AFLP标记在研究贵州小型香猪遗传多态性方面的应用和该品系猪个体基因组DNA的AFLP扩增结果,分析了贵州小型香猪的群体遗传结构.实验应用10条AFLP引物,用PstⅠ酶切,对17头猪基因组DNA进行AFLP反应,共获得116个AFLP标记,单引物获得的标记数在2~22间,贵州小型香猪群体相似系数AFLP研究结果为0.866(0.760~0.967),该研究为评价贵州小型香猪的遗传稳定性提供了相关的参数,准确评价尚待和其它品种猪对比研究后确定。 Abstract:We reported the application of AFIP markers to detect genetic polymorphic loci in Guizhou miniaturc pig and their amplified AFLP results.Their genetic construction Of the population was also analysed.TenAFLP primers were used,genomic DNAs from 17 pigs were restrictive by pst I,116 AFLP markers were obtained,the obtaining marker numbers of individual primer were between 2~22.The results indicate as the following:(1)AFLP marker is suitable for analysing genetic polymorphism in pig;(2)The similarty index of population in Guizhou miniaturc pigs was 0.866(0.760~0.967).The study provides a uscful parameter with appraise genetic stability of Guizhou miniature pigs.  相似文献   
63.
用40条多态引物对乌羊、小香羊、南江黄羊、黑山羊、川东白山羊、波尔山羊和马头山羊7个品种(或群体)进行RAPD分析,其中28条引物扩增出多态性谱带,并用于进一步对12只乌羊个体和12只小香羊个体基因组进行扩增.扩增产物以1.5%琼脂糖凝胶(含0.5μg/ml溴化乙锭)电泳分离.Nei氏公式计算品种间的遗传距离指数和品种内的遗传相似指数,NJ法构建系统聚类图.结果表明:乌羊和川东白山羊间的遗传距离最小,亲缘关系较近,而小香羊与各品种间的遗传距离都较大,亲缘关系较远.乌羊群体及小香羊品种都具有一定的遗传稳定性。 Abstract:A total of 40 primers generated polymorphic loci were used in random amplified polymorphism DNA(RAPD)analysis in seven goat breeds(or populations)including Wu goat,Small-Xiang goat,Nanjiang Brown goat,Black goat,Chuandong white goat,Boer goat,Matou goat.28 of them were selected for further amplification in individuals of 12 Wu goats and 12 Small-Xiang goats because of their different amplified patterns among seven goat breeds.Amplification products were separated by 1.5% agarose gel(contain 0.5μg/ml ethidium bromide)electrophoresis.Genetic distance indexes among breeds and genetic similarity indexes within breed were calculated by Nei,and the phylogenetic tree was constructed by NJ method.The results indicate that the genetic distance index between Wu goat population and Chuandong white goat breed is smallest,therefore Wu goat population is closely related to Chuandong white goat breed.While the genetic distance indexes between Small-Xiang goat breed and any other goat breeds are all big,so Small-Xiang goat breed is far related to any other goat breeds.The results also indicate that the genetic stability either among the Wu goat population or the Small-Xiang goat breed reaches some extent.  相似文献   
64.
近交系小鼠微卫星DNA多态性的研究   总被引:8,自引:0,他引:8  
随机选择位于小鼠不同染色体上的微卫星引物42对,用PCR技术对C3H、C57、BALB/c、DBA、TA2、T739、B615、BACB/c-nu-nu和SCID等9种实验室常用近交系小鼠微卫星DNA多态性进行了研究。结果显示有信息的40对引物中,9种近交系小鼠在各基因座上均出现一条清晰条带,28个基因座表现为多态性。其中D3Mit22、D7Nds1、D11Mit12、D12Nds2、D15Mit17、D16Mit3、D16Mit4基因座表现为显著多态性。T739、B615和TA2的遗传背景相近,其相似系数分别为90%和85%;其次为TA2、SCID和B615,其相似系数分别为80%和82.5%。结果表明所检测的小鼠符合近交要求,筛选出的引物能典型地反映9个近交系小鼠的品系特异性和遗传背景,可用于常规检测小鼠品系来源和遗传背景等。 Abstract:Forty-two microsatellites DNA loci on different chromosomes in nine kinds of inbred strain mice including C3H,C57,BALB/c,DBA,TA2,T739,B615,BALB/c-nu-nu and SCID were investigated by PCR analysis.It showed that all these mice tested display single allelic gene band with forty pairs of informative primers.Twenty-eight loci are polymorphisms,among which the polymorphisms of D3Mit22,D7Nds1,D11Mit12,D12Nds2,D15Mit17,D16Mit3,and D16Mit4 loci are significant.The genetic background of T739 was similarity with that of B615 and TA2 ,the similarity indices were 90% and 85% respectively;and that of TA2 was similarity with SCID and B615,the similarity indices were 80% and 82.5%.These results suggest that these mice tested meet the request of inbred strain.Screened primers showing marked polymorphisms topically reflect the speciality of strains and genetic backgrounds,which could be used in determining the strains origin and genetic background of mice.  相似文献   
65.
云南塔城滇金丝猴掘食行为的初步研究   总被引:2,自引:0,他引:2  
2006年3月至2007年5月,我们对云南塔城一个滇金丝猴群进行了连续跟踪,旨在调查其生境利用情况.在此期间,我们发现滇金丝猴在地面有掘土行为.通过照片分析,发现滇金丝猴的这种掘食行为旨在获取某种植物地下球茎.后分别在两个地点采用焦点动物行为记录法对这种掘食行为进行了记录.通过比较单次掘食行为的持续时间、掘食行为的发生频次以及掘取成功率,我们发现这些指标在不同年龄-性别组个体间的差异明显.成年雄猴的成功率明显高于其它两组;在单次掘食行为的时间花费上,成年雄猴和雌猴之间无差别,而亚成年个体表现为用时短和变换挖掘地点频繁的特点.就雄猴而言,成年有助于掘食成功.同时发现,带新生仔的雌猴也会下地采掘,但尚无成功采食纪录.进食植物球茎的过程中未发现分享块茎行为,但有抢食表现.  相似文献   
66.
补偿能力和适口性对放牧群落植物优势度的影响   总被引:3,自引:0,他引:3  
通过模拟刈割试验和样方调查,研究了9种植物的补偿能力及其在放牧群落中优势度变化趋势.结果表明:多数植物的补偿能力与适口性有一定的相关性,适口性较好的多枝黄芪、金花苜蓿、矮嵩草及珠芽蓼的补偿指数较高,分别为1.013、0.907、0.849和0.802,垂穗披碱草(0.668)次之,适口性差的藏蒲公英、獐牙菜及细叶亚菊的补偿指数较低,分别为0.649、0.587和0.553;中华羊茅的适口性较好,但其补偿指数最低,为0.473.优势度变化呈增加型、减少型、中性3种放牧反应类型,其中,中华羊茅为减少型,多枝黄芪、珠芽蓼、垂穗披碱草为中性型,其余5种为增加型.补偿能力、适口性在一定程度上可以解释植物在放牧群落中优势度的变化趋势.  相似文献   
67.
魏丽珠  伏洁  刘光陵  王晓燕  王兆全 《遗传》1999,21(2):13-609
为了探讨神经肌肉性疾病的发病与线粒体DNA突变的关系,采用PCR技术检测了 20例患有不同神经肌肉性疾病儿童的外周血和骨骼肌细胞中的线粒体DNA(mtDNA),发现其中6例患儿有mtDNA缺失,其中1例至少有2968bp片段的缺失, 另5例至少有2000bp片段的缺失,此缺失区位于线粒体呼吸链复合物1、 4、5、编码区,表明该突变对神经肌肉性疾病的发生有一定作用。 Abstract:To understand the relation to mechanism of neuromuscular disease and mtDNA mutation,using PCR technique,we investigated blood and /or skeletal muscle of 20 patients with neuromuscular diseases.A deletion in the length of 2000~2968bp was found in blood mitochondrial DNA of 6 patients with neuromuscular disease.The deletion region partially lies in the coding region of resoiratony chain complex 1,4,5.It is suggested that this mutation ois related with neuromuscular diseases.  相似文献   
68.
采用盆栽试验,研究了以城市污泥堆肥为主要原料的基质对观花植物香彩雀(Angelonia salicariifolia Humb.)生长和开花特性的影响,并采用熵权系数与TOPSIS集成评价法综合评价了不同基质对香彩雀的生长适应性。结果表明,经过60 d高温好氧堆制的污泥堆肥,以不同体积比与泥炭、河沙混配成的栽培基质容重和EC值比研究区的林地赤红壤低,pH值和养分含量更高。污泥堆肥混合基质栽培的香彩雀营养生长和生殖生长均优于土壤栽培,其中株高比后者增加29%~61%,分枝数增加27%~67%,鲜重增加17%~88%,干重增加4%~50%,开花时间提前2~16 d,花朵数增加49%~220%,花期延长8~22 d,花朵畸形率降低1%~5%,对氮、磷、钾的吸收能力显著提高。试验中各种污泥堆肥混合基质均适合香彩雀生长,熵权系数与TOPSIS集成评价结果显示,在所研究的污泥堆肥基质中,污泥堆肥:泥炭:河沙体积比为5∶3∶2的基质植物适应性最强,纯污泥堆肥植物适应性相对较差,但优于土壤。将污泥堆肥作为基质主要成分用于花卉生产,既可提高花卉质量,降低成本,又能消耗大量污泥,是城市污泥资源化处置和利用的重要方向。  相似文献   
69.
Transfection of cDNA in 3'untranslated region of human nuclear factor for interleukin-6 (NF-IL6 3'UTR) induced tumor suppression in a human hepatoma cell line. cDNA array analysis was used to reveal changes in gene expression profile leading to tumor suppression The results indicate that this suppression was not due to activation of dsRNA-dependent protein kinase, nor to inactivation of oncogenes; rather, all the changes in expression of known genes, induced by NF-IL6 3'UTR cDNA may be ascribed to the suppression of cellular malignancy. Therefore, our results imply that this 3'untranslated region may have played role of a regulator of gene expression profile.  相似文献   
70.
Based on the sequence information of Arabidopsis PIN1, two cDNAs encoding PIN homologues from Brassica juncea, Bjpin2 and Bjpin3, were isolated through cDNA library screening. Bjpin2 and Bjpin3 encoded proteins containing 640 and 635 amino acid residues, respectively, which shared 97.5% identities with each other and were highly homologous to Arabidopsis PIN1, PIN2 and other putative PIN proteins. BJPIN2 and BjPIN3 had similar structures as AtPIN proteins. Northern blot analysis indicated that Bjpin2 was expressed in stem, leaf and floral tissues, while Bjpin3 was expressed predominantly in stem and hypocotyls. Two promoter fragments of pin genes, Bjpin-X and Bjpin-Z, were isolated by 'genome walking' technique using primers at 5'-end of pin cDNA. Promoter-gus fusion studies revealed the GUS activities driven by Bjpin-X were at internal side of xylem and petal; while those driven by Bjpin-Z were detected at leaf vein, epidermal cell and cortex of stem, vascular tissues and anther. Results of the pin gene  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号