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排序方式: 共有143条查询结果,搜索用时 15 毫秒
91.
猪CFL2b基因主要在骨骼肌中表达,对肌肉的发育和肌纤维的形成具有一定作用。为了解猪CFL2b基因与肌纤维性状的相关性,利用定向克隆和基因转染技术获得能稳定表达猪CFL2b基因的成肌细胞株,荧光显微镜观察及Western Blotting检测CFL2b基因在成肌细胞中的表达;应用实时定量PCR技术对细胞内肌球蛋白重链基因(MyHC)的表达变化进行检测。结果显示:CFL2b基因对MyHC的表达有明显影响,其中MyHC2x基因和MyHC26基因的表达明显上调,MyHCl/slow的表达变化不明显。表明CFL2b基因与猪的肌纤维性状密切相关,推测猪CFL2b基因的高表达可能导致猪的不良肉质性状,可以考虑将CFL2b基因作为猪肉质性状的候选基因[动物学报54(6):1014—1019,2008]。  相似文献   
92.
We report here the new ‘creodont’ Lahimia selloumi gen. et sp. nov. from the late Palaeocene of the Ouled Abdoun Basin (Morocco) as the oldest known Hyaenodontidae with Tinerhodon from the Ouarzazate Basin (Morocco). By contrast to Tinerhodon, Lahimia is unexpectedly derived. Most of its specializations, such as the shortening of the anterior dentition (e.g. loss of P1) and the talonid reduction and simplification, are strikingly shared with Boualitomus from the Ypresian of the Ouled Abdoun Basin, and are distinctive from other hyaenodontids, including ‘proviverrines’. They are interpreted as synapomorphies evidencing a precociously specialized early African hyaenodontid lineage. Although Lahimia and Boualitomus remain known only by the lower dentition, their relationships with Koholia are suggested by comparison of their molar occlusal pattern. Lahimia and Boualitomus are referred to the Koholiinae, which is representative of an old African endemic lineage, as initially recognized. This remarkable lineage is characterized by synapomorphies of Lahimia and Boualitomus, and also by a shared original prevallum/postvallid shearing. The discovery of Lahimia provides direct evidence for the antiquity of the African evolution of the Hyaenodontidae. This is in agreement with an African origin of the Hyaenodontidae, and with the probable diphyletism of the ‘Creodonta’. Lahimia and the Koholiinae, as well as the diversity of the first Laurasian hyaenodontid lineages, emphasize our poor knowledge of the striking early African hyaenodontid radiation.  相似文献   
93.
The presence of anti-alpha-fodrin autoantibodies has been reported to be a highly specific and sensitive test for the diagnosis of Sj?gren's syndrome (SjS). We looked (in Nijmegen) for anti-alpha-fodrin, anti-Ro60, and anti-La autoantibodies in a cohort of 51 patients with rheumatic diseases (primary SjS [21], secondary SjS 6, rheumatoid arthritis [RA] 12, systemic lupus erythematosus [SLE] 6, and scleroderma 6) and in 28 healthy subjects, using ELISA, immunoblotting, and immunoprecipitation. The same samples were analyzed with an alternative anti-alpha-fodrin ELISA in Hanover. The Nijmegen ELISA of the sera from primary SjS showed sensitivities of 43% and 48% for IgA- and IgG-type anti-alpha-fodrin antibodies, respectively. The Hanover ELISA showed sensitivities of 38% and 10% for IgA- and IgG-type anti-alpha-fodrin antibodies, respectively. The ELISAs for alpha-fodrin showed six (Nijmegen) and four (Hanover) anti-alpha-fodrin-positive RA sera. IgA and IgG anti-fodrin antibodies were also present in four patients with secondary SjS. The sensitivities of Ro60 and La-antibodies in the Nijmegen ELISA were 67% and 62%, respectively. Unlike anti-alpha-fodrin antibodies, all anti-Ro60 and anti-La positive sera could be confirmed by immunoblotting or RNA immunoprecipitation. Thus, anti-Ro and anti-La autoantibodies were more sensitive than anti-alpha-fodrin autoantibodies in ELISA and were more frequently confirmed by other techniques. Anti-La antibodies appear to be more disease-specific than anti-alpha-fodrin antibodies, which are also found in RA sera. Therefore, the measurement of anti-alpha-fodrin autoantibodies does not add much to the diagnosis of Sj?gren's syndrome.  相似文献   
94.
本研究用Vero细胞或Vero/SLAM细胞从我国10个省(直辖市、自治区,下同)2003~2007年风疹暴发和散发病例的咽拭子标本中分离到57株风疹病毒,用RT-PCR方法扩增了57株风疹病毒E1基因1 107个核苷酸的片段,并对该PCR产物进行序列测定和分析.结果提示,在基于WHO基因定型靶序列739个核苷酸片段构建的基因亲缘关系树上,其中55株风疹病毒株属于1E基因型,相对于其他国家的1E基因型,形成一个独立分支;另外2株风疹病毒属于2B基因型.57株风疹病毒大部分核苷酸的突变为无义突变,氨基酸序列高度保守,除了2株风疹病毒在E1蛋白血凝抑制和中和位点区域第212位氨基酸由Thr变为Ser,其他病毒株均无重要抗原位点的改变;所有我国已分离到的1E基因型风疹病毒在E1蛋白第338位氨基酸共享突变位点(Leu338→Phe338),而其他基因型以及其他国家的1E基因型风疹病毒在该位点均未发生突变,提示该氨基酸(Phe338)可能是我国1E基因型风疹病毒所特有.2003~2007年在我国10个省均分离到1E基因型,而2B基因型只在2006年从四川省的越南输入病例中分离到,提示1E为绝对优势基因型,2B基因型为输入基因型.与1979~1984年和1999~2002年我国流行的风疹基因型不同,发生了基因型的更替,近年我国风疹的流行是由1E基因型为主的风疹野病毒的多个传播链引起.  相似文献   
95.
Fibroblast growth factor ligands and receptors (FGF and FGFR) play critical roles in tumorigenesis, and several drugs have been developed to target them. We report the biologic correlates of FGF/FGFR abnormalities in diverse malignancies. The medical records of patients with cancers that underwent targeted next generation sequencing (182 or 236 cancer-related genes) were reviewed. The following FGF/FGFR genes were tested: FGF3, 4, 6, 7, 10, 12, 14, 19, 23 and FGFR1, 2, 3, and 4. Of 391 patients, 56 (14.3%) had aberrant FGF (N = 38, all amplifications) and/or FGFR (N = 22 including 5 mutations and one FGFR3-TACC3 fusion). FGF/FGFR aberrations were most frequent in breast cancers (26/81, 32.1%, p = 0.0003). In multivariate analysis, FGF/FGFR abnormalities were independently associated with CCND1/2, RICTOR, ZNF703, RPTOR, AKT2, and CDK8 alterations (all P < 0.02), as well as with an increased median number of alterations (P < 0.0001). FGF3, FGF4, FGF19 and CCND1 were co-amplified in 22 of 391 patients (5.6%, P < 0.0001), most likely because they co-localize on the same chromosomal region (11q13). There was no significant difference in time to metastasis or overall survival when comparing patients harboring FGF/FGFR alterations versus those not. Overall, FGF/FGFR was one of the most frequently aberrant pathways in our population comprising patients with diverse malignancies. These aberrations frequently co-exist with anomalies in a variety of other genes, suggesting that tailored combination therapy may be necessary in these patients.  相似文献   
96.
97.
应用稳定性同位素技术(δ13C、δ15N)对2011年3月至2013年12月采自长江中游干流宜昌、荆州、石首、监利、城陵矶、鄂州、九江和湖口江段的44种鱼类及3种水生无脊椎动物进行了营养级研究。长江中游干流鱼类的δ13C值范围﹣33.83‰(鳙Aristichthys nobilis) ~ ﹣17.36‰(南方鲇Silurus meridionalis),δ15N值范围4.83‰(泥鳅Misgurnus anguillicaudatus)~ 15.13‰(翘嘴鲌Culter alburnus)。以梨形环棱螺(Bellamya purificata)的δ15N均值5.48‰作为营养级基准线(营养级 = 2),计算出该江段水生动物的营养级处于2.42 ~ 4.88,主要集中在2.83 ~ 3.61之间,鱼类平均营养级为3.28。营养级大于2.83的鱼类种类数量占了总生物种数的80.85%。大刺鳅(Mastacembelus armatus)和长春鳊(Parabramis pekinensis)营养级最低,分别为2.42 ± 0.49和2.56 ± 0.52,营养层级大于4.0的高级消费者为太湖新银鱼(Neosalanx taihuensis)、短颌鲚(Coilia brachygnathus)、鳙和长蛇鮈(Saurogobio dumerili),分别为4.88 ± 0.01、4.37 ± 0.27、4.32 ± 0.35和4.09 ± 0.78,小黄黝鱼(Micropercops swinhonis)、鱤(Elopichthys bambusa)、鱖(Siniperca chuatsi)、翘嘴鲌、青鱼(Mylopharyngodon piceus)和南方鲇的营养级分别3.99、3.92 ± 0.16、3.89 ± 0.27、3.87 ± 0.62、3.59 ± 0.69和3.59 ± 0.57。本研究旨为长江中游渔业资源评估及其合理利用提供基础科学资料,为进一步研究长江中游干流渔业资源营养结构的动态变化及受人为活动干扰影响等提供科学参考依据。  相似文献   
98.
Variation at five polymorphic microsatellite loci was used to investigate genetic diversity and differentiation of two tetraploid Canarian endemics, Bencomia exstipulata and B. caudata. Data were analysed and are discussed in terms of tetrasomic (autotetraploid) and disomic (allotetraploid) inheritance. In both cases, genetic diversity values were similar to those described in other tetraploid plant species. High genetic differentiation between the only two described natural populations of B. exstipulata was detected (FST = 0.411). Bayesian cluster analysis revealed a geographical structure with distinct genetic groups from each island. High genetic differentiation and low genetic diversity of the B. exstipulata population from Tenerife suggest a recent population bottleneck, perhaps caused by the most recent major volcanic eruption, for this natural locality. This may be heightened by possible inbreeding depression and the monoecy of these species. Polymorphic microsatellite loci were also tested across all species in the Bencomia alliance. These reliably amplified the target sequence, suggesting a high degree of conservation of the sequences flanking the microsatellites. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 429–441.  相似文献   
99.
Evidence for bacterial urea production in marine sediments   总被引:1,自引:0,他引:1  
Abstract The quantitative importance of bacteria in urea production and turnover in a defaunated sediment from a Danish estuary was studied. After collecting the sediment, benthic infauna was removed by sieving, followed by anoxic pre-incubation for a week. Yeast extract was added to half of the samples. The urea concentration, urea production/turnover rates and the net ammonium production rate, were followed during a 338 h incubation. The urea concentration was highest in the enriched sediment, although urea production and turnover rates were the same in the enriched and control sediment, indicating that the urea concentration was controlled by the urea turnover rate constant, k urea. Net ammonium production, urea concetrations and teh urea turnover declined towards the end of the experiment. Comparison of the net ammonium production rate and the urea turnover rate in the enriched and control treatments, showed that urea hydrolysis accounted for up to 100% of the ammonium produced, from all sources. More than 98% of the urea which was hydrolyzed, originated from production during incubation. This suggests that urea was a major nitrogen excretion product from bacteria in this sediment, and that bacteria could also be an important source of urea in other marine sediments.  相似文献   
100.
将汉滩病毒囊膜糖蛋白G1与核蛋白(NP)部分片段以不同方式拼 接,构建G1S0.7或S0.7G1嵌合基因,分别插入杆状病毒表达载体pFBD,转化DH10Bac致敏菌, 获得含有嵌合基因的重组穿梭质粒Bacmid,用其转染Sf9细胞,快速筛选出含有G1S0.7或S0.7 G1嵌合 基因的重组杆状病毒,在昆虫细胞中表达外源融合蛋白.利用间接免疫荧光、ELISA和免疫 印迹对表达产物进行检测.结果表明,含G1S0.7嵌合基因之重组杆状病毒可在昆虫细胞中表 达出融合蛋白,该蛋白可被抗汉滩病毒核蛋白及糖蛋白G1特异性单抗所识别,其分子量约97 kD;含S0.7G1嵌合基因之重组杆状病毒在昆虫细胞中表达的融合蛋白,只能被抗汉滩病毒核 蛋白特异性单抗所识别,其分子量约43kD.上述结果提示,G1S0.7嵌合基因可能在昆虫细胞 中表达出完整的具有生物学活性的融合蛋白,S0.7G1嵌和基因的昆虫细胞表达产物不完整 ,且生物学活性不如G1S0.7嵌合基因的表达产物.  相似文献   
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