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991.
目的:构建携带IGF2印迹系统的腺病毒载体,并验证其在肿瘤细胞及正常细胞中的功效,为IGF2印迹在肿瘤靶向治疗中的应用提供理论基础.方法:将人源的IGF2印迹系统启动子H19、增强子enhancer及甲基化区域CTCF克隆至穿梭质粒pDC-312中构建IGF2基因印迹系统,从pDC-315-EGFP质粒中扩增出EGFP片段插入到构建好的IGF2印迹系统中,然后与腺病毒骨架Ad5通过脂质体Lipofectamine2000介导共转染HEK293细胞,包装成有感染能力的腺病毒Ad-H19-CTCF-enlmncer-EGFP,命名为Ad-EGFP;构建好的腺病毒分别感染IGF2基因印记保持的细胞MCF-7和GES-1及IGF2基因印迹丢失的细胞HRT-18,荧光显微镜下观察EGFP在三种细胞中表达的差异.结果:转染腺病毒载体的HEK293细胞表达EGFP随着时间逐渐增强,并且出现明显的细胞病变效应,EGFP在HRT-18细胞中有大量表达,在MCF-7和GES-1细胞中不表达或仅有少量表达.结论:成功构建了携带IGF2基因印迹系统的腺病毒载体,证明其在IGF2基因印迹丢失的肿瘤细胞中特异性的表达,在正常细胞及IGF2基因印迹保持细胞中不表达,为IGF2基因印迹系统应用于肿瘤细胞的靶向治疗提供了理论基础. 相似文献
992.
稻草秸秆纤维素分解菌的分离筛选 总被引:7,自引:0,他引:7
本研究基于获得高效木质纤维素分解菌的目的,以刚果红纤维素琼脂和滤纸条培养基为初筛培养基,从分离获得的124株真菌中筛选出透明圈与菌落直径比值较大、滤纸条分解能力较强的11个菌株.经液体发酵,测定其酶活力,复筛得到羧甲基纤维素酶活和滤纸酶活均较高的4个菌株;并进行了不同碳源和不同pH对筛选菌株产酶能力的影响试验,发现不同菌株对不同纤维素物质的分解能力不一样,同一菌株对不同纤维素碳源的利用能力也不相同. 相似文献
993.
Genomic imprinting, representing parent-specific expression of alleles at a locus, is mainly evident in flowering plants and
placental mammals. Most imprinted genes, including numerous non-coding RNAs, are located in clusters regulated by imprinting
control regions (ICRs). The acquisition and evolution of genomic imprinting is among the most fundamental genetic questions.
Discoveries about the transition of mammalian imprinted gene domains from their non-imprinted ancestors, especially recent
studies undertaken on the most ancient mammalian clades — the marsupials and monotremes from which model species genomes have
recently been sequenced, are of high value. By reviewing and analyzing these studies, a close connection between non-coding
RNAs and the acquisition of genomic imprinting in mammals is demonstrated. The evidence comes from two observations accompanied
with the acquisition of the imprinting: (i) many novel non-coding RNA genes emerged in imprinted regions; (ii) the expressions
of some conserved non-coding RNAs have changed dramatically. Furthermore, a systematical analysis of imprinted snoRNA (small
nucleolar RNA) genes from 15 vertebrates suggests that the origination of imprinted snoRNAs occurred after the divergence
between eutherians and marsupials, followed by a rapid expansion leading to the fixation of major gene families in the eutherian
ancestor prior to the radiation of modern placental mammals. Involved in the regulation of imprinted silencing and mediating
the chromatins epigenetic modification may be the major roles that non-coding RNAs play during the acquisition of genomic
imprinting in mammals.
Supported by National Natural Science Foundation of China (Grant No. 30830066), the Ministry of Education of China and Natural
Science Foundation of Guangdong Province (Grant No. IRT0447, NSF-05200303) and National Key Basic Research and Development
Program of China (Grant No. 2005CB724600) 相似文献
994.
995.
Hua Zhang Jian-Hua Yang Yu-Sheng Zheng Peng Zhang Xiao Chen Jun Wu Ling Xu Xue-Qun Luo Zhi-Yong Ke Hui Zhou Liang-Hu Qu Yue-Qin Chen 《PloS one》2009,4(9)
Background
MicroRNAs (miRNAs) have been proved to play an important role in various cellular processes and function as tumor suppressors or oncogenes in cancers including leukemia. The identification of a large number of novel miRNAs and other small regulatory RNAs will provide valuable insights into the roles they play in tumorgenesis.Methodology/Principal Findings
To gain further understanding of the role of miRNAs relevant to acute lymphoblastic leukemia (ALL), we employed the sequencing-by-synthesis (SBS) strategy to sequence small RNA libraries prepared from ALL patients and normal donors. In total we identified 159 novel miRNAs and 116 novel miRNA*s from both libraries. Among the 159 novel miRNAs, 42 were identified with high stringency in our data set. Furthermore, we demonstrated the different expression patterns of 20 newly identified and several known miRNAs between ALL patients and normal donors, suggesting these miRNAs may be associated with ALL and could constitute an ALL-specific miRNA signature. Interestingly, GO “biological process” classifications revealed that a set of significantly abnormally expressed miRNAs are associated with disease relapse, which implies that these dysregulated miRNAs might promote the progression of ALL by regulating genes involved in the pathway of the disease development.Conclusion/Significance
The study presents a comprehensive picture of the expression of small RNAs in human acute lymphoblastic leukemia and highlights novel and known miRNAs differentially expressed between ALL patients and normal donors. To our knowledge, this is the first study to look at genome-wide known and novel miRNA expression patterns in in human acute lymphoblastic leukemia. Our data revealed that these deregulated miRNAs may be associated with ALL or the onset of relapse. 相似文献996.
997.
目的:研究孤啡肽(N/OFQ)对大鼠顶叶皮层神经元瞬时外向钾电流(IA)的影响,初步探讨其作用的通道动力学机制。方法:采用全细胞膜片钳技术,观察N/OFQ对急性分离的大鼠顶叶皮层神经元IA的作用。结果:①0.1μmol/L N/OFQ使IA幅值由给药前的(5356.1±361.6)pA下降为(4113.3±312.7)pA,抑制率为23.20%±2.17%(P〈0.01,n=10)。②0.1μmol/L N/OFQ使IA的电流-电压(I-V)曲线降低(P〈0.01,n=10)。③0.1μmol/L N/OFQ使,IA激活曲线的半数激活电压(V1/2)和斜率因子(κ)分别由给药前的(-9.2±2.5)mV和(20.4±2.3)mV变为给药后的(30.6±3.7)mV(P〈0.01,n=8)和(22.6±2.1)mV(P〉0.05,n=8)。④0.1μmol/L N/OFQ使IA失活曲线的半数失活电压(V1/2)和斜率因子(κ)分别由给药前的(-64.1±3.2)mV和(21.5±2.1)mV变为给药后的(-55.9±1.9)mV(P〈0.05,n=5)和(19.6±2.2)mV(P〉0.05,n=5)。结论:N/OFQ可抑制大鼠顶叶皮层神经元IA,使其激活曲线、失活曲线均右移。 相似文献
998.
旨在研究蛋白G IgG Fc段结合域(PGFB)的克隆、表达及其抗体结合功能,用于抗体的纯化.根据PGFB的氨基酸序列,选择大肠杆菌偏爱的密码子,设计并合成了4个寡核苷酸片段.通过重叠延伸PCR方法合成了PGFB DNA片段,测序鉴定后克隆至原核表达系统pET-28a-c(+)上,转化大肠杆菌,获得表达菌株;IPTG诱导表达PGFB,经Ni+-NTA琼脂糖凝胶层析纯化后偶联到琼脂糖凝胶6B上,用其纯化多克隆抗体.结果显示,PGFB在大肠杆菌BL21(DE3)中获得高效表达,纯化后纯度达到90%以上,相对分子量为12.25 kD,与预期值相符.此外,偶联产物纯化多克隆抗体达到了良好的效果,每毫升基质可结合20 mg抗体.本研究克隆构建并高效表达了具有较好抗体亲和能力的PGFB,为多克隆抗体的快速纯化提供了方便. 相似文献
999.
1000.