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   216篇
  免费   20篇
  国内免费   32篇
  2024年   3篇
  2023年   7篇
  2022年   15篇
  2021年   16篇
  2020年   6篇
  2019年   24篇
  2018年   16篇
  2017年   6篇
  2016年   11篇
  2015年   21篇
  2014年   20篇
  2013年   17篇
  2012年   23篇
  2011年   19篇
  2010年   13篇
  2009年   4篇
  2008年   6篇
  2007年   7篇
  2006年   9篇
  2005年   4篇
  2004年   4篇
  2003年   1篇
  2002年   1篇
  1999年   1篇
  1998年   4篇
  1997年   5篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
排序方式: 共有268条查询结果,搜索用时 15 毫秒
1.
目的研究大豆异黄酮促进骨质疏松大鼠骨形成的作用及其肠道微生态的变化。方法从60只SPF级SD雌性大鼠中随机挑选50只建立去卵巢骨质疏松大鼠模型,余下10只为假手术组。将建模成功的大鼠随机分为5组,模型组、大豆异黄酮高、中、低剂量组(320 mg/kg、160 mg/kg、80 mg/kg的大豆异黄酮)、阿仑膦酸钠组(1 mg/kg阿仑膦酸钠),每日1次,治疗10周。比较治疗前后大鼠骨密度、血清1型前胶原N端前肽(P1NP)、骨碱性磷酸酶(BALP)、血清骨钙素(BGP)水平和肠道微生物变化。结果治疗后,模型组大鼠骨密度、血清P1NP、BALP、BGP水平均低于假手术组(P<0.05),阿仑膦酸钠组和大豆异黄酮高、中、低剂量组均高于模型组(P<0.05)。治疗后,阿仑膦酸钠组和大豆异黄酮高、中、低剂量与模型组比较股骨组织病变减轻;厚壁菌门、梭菌纲、芽孢杆菌纲、毛螺菌科、乳杆菌科、普氏菌科、肠球菌科、毛螺菌属、乳杆菌属、罗氏菌属、布劳特氏菌属、粪球菌属、普氏菌属水平相对丰度模型组均低于假手术组(P<0.05),阿仑膦酸钠组和大豆异黄酮高、中、低剂量组均高于模型组(P<0.05)。拟杆菌门、变形菌门、拟杆菌纲、γ变形菌纲、毛菌纲、拟杆菌科、肠杆菌科、拟杆菌属、别样棒菌属、肠杆菌属模型组均高于假手术组(P<0.05),阿林磷酸钠组和大豆异黄酮高、中、低剂量组均低于模型组(P<0.05)。LEfSe分析结果显示,与模型组比较,阿仑膦酸钠组和大豆异黄酮高、中、低剂量组治疗后丁酸球菌属、放线菌属、拟杆菌科、拟杆菌属水平降低,消化球菌科、韦荣氏菌科、普氏菌属水平升高。结论大豆异黄酮可提高骨密度,提高血清骨形成指标水平,促进骨质疏松大鼠骨形成,还可改善大鼠肠道菌群。  相似文献   
2.
Little is known about the role of the host defensive protein short palate, lung and nasal epithelium clone 1 (SPLUNC1) in the carcinogenesis of nasopharyngeal carcinoma (NPC). Here we report that SPLUNC1 plays a role at a very early stage of NPC carcinogenesis. SPLUNC1 regulates NPC cell proliferation, differentiation and apoptosis through miR-141, which in turn regulates PTEN and p27 expression. This signaling axis is negatively regulated by the EBV-coded gene LMP1. Therefore we propose that SPLUNC1 suppresses NPC tumor formation and its inhibition by LMP1 provides a route for NPC tumorigenesis.  相似文献   
3.
This Letter details the synthesis and evaluation of imidazo[4,5-b]pyridines as inhibitors of B-Raf kinase. These compounds bind in a DFG-in, αC-helix out conformation of B-Raf, which is a binding mode associated with significant kinase selectivity. Structure–activity relationship studies involved optimization of the ATP-cleft binding region of these molecules, and led to compound 23, an inhibitor with excellent enzyme/cell potency, and kinase selectivity.  相似文献   
4.
Rice(Oryza sativa) is one of the most widely cultivated food crops, worldwide. Tissue culture is extensively used in rice breeding and functional genome research. The ability to induce callus determines whether a particular rice variety can be subjected to tissue culture and Agrobacterium-mediated transformation. Over the past two decades, many quantitative trait loci(QTLs)related to callus induction traits have been identified;however, individual genes associated with rice callus induction have not been reported. In this study, we characterized three callus-induction traits in a global collection of 510 rice accessions. A genome-wide association study of the rice population in its entirety as well as subpopulations revealed 21 significant loci located in rice callus induction QTLs. We identified three candidate callus induction genes, namely CRL1, Os BMM1, and Os SET1, which Rese are orthologs of Arabidopsis LBD17/LBD29, BBM, and SWN,respectively, which are known to affect callus formation.Furthermore, we predicted that 14 candidate genes might be involved in rice callus induction and showed that RNA interference(RNAi)-mediated disruption of Os IAA10 inhibited callus formation on tissue culture medium.Embryo growth in the Os IAA10 RNAi line was not inhibited by synthetic auxin(2,4-D) treatment, suggesting that Os IAA10 may perceive auxin and activate the expression of downstream genes, such as CRL1, to induce callus formation. The significant loci and candidate genes identified here may provide insight into the mechanism underlying callus formation in rice.  相似文献   
5.
This study was to investigate the biological function and underlying mechanisms of FENDRR in cholangiocarcinoma (CCA) cell proliferation, migration and invasion. FENDRR and survivin expression in CCA tissues or cell lines were measured by qRT-PCR. In QBC939 and HuCCTl cells, cell proliferation was detected by CCK-8, cell migration and invasion were using transwell assay. RNA pull-down and RIP assay were performed to determine whether FENDRR can combine with SETDB1 in CCA cell. The effect of SETDB1 on survivin and H3K9me1 expression in CCA cells were determined by western blotting. ChIP analysis was performed to analyze the combination of SETDB1 with survivin promoter in CCA cell. The effect of SETDB1 knockdown on survivin and H3K9me1 expression in CCA cells after transfection with FENDRR were determined by western blotting. The results showed that lncRNA FENDRR was downregulated in CCA tissues and cells, and was negatively correlated with survivin expression. Further investigation demonstrated that FENDRR represses CCA cell proliferation, migration and invasion through regulating survivin expression. FENDRR associated with SETDB1 and H3K9 to epigenetically silence survivin and then regulated cell proliferation, migration and invasion. These findings indicate an important role for FENDRR–survivin axis in CCA cell proliferation, migration and invasion, and reveal a novel epigenetic mechanism for survivin silencing. Our data indicated that FENDRR silences survivin via SETDB1-mediated H3K9 methylation, thereby represses CCA cell proliferation, migration and invasion.  相似文献   
6.
白及为兰科白及属植物。作为著名中药,白及功效多样、用途广泛,具有较高的药用价值和经济价值。随资源利用强度的增加,野生白及资源日渐萎缩,人工规模化种植是实现白及药用资源可持续利用的必由之路。优良种质及繁育技术是种植业的关键问题。为了更好地推动白及资源研究和可持续利用,本文就白及种质及快繁技术研究进展作一综述,并就白及资源再生策略进行初步探讨,为相关研究和生产提供参考。  相似文献   
7.
为了解睡莲花朵的致香物质,利用气相色谱-质谱法对62个栽培种花朵的挥发性成分进行了研究。结果表明,共检测出72种挥发性成分,以烯烃类(26种)、烷烃类(11种)和醇类(9种)较多,其中花香成分有53种(73.60%)。40个热带睡莲花朵中共检测出56种挥发性成分,其中花香成分39种;22个耐寒睡莲品种花朵共检测出37种挥发性成分,其中花香成分27种。花香成分中主要致香物质有乙酸苄酯、顺式-罗勒烯、苯甲醇、金合欢烯、月桂烯、柠檬烯、苯甲醛、α-异松油稀、α-蒎烯、肉桂醇和β-丁香醇等。利用组内联接余弦的方法,分别根据挥发性成分和花香成分,62个睡莲栽培种(品种)可分成3和4组。这为睡莲香气物质的开发利用及与传粉动物的协同进化研究提供了基础资料。  相似文献   
8.
The complete mitogenome of Haliotis iris, an economically important shellfish endemic to New Zealand, was sequenced for the first time. The mitogenome was 17,131?base pairs (bp) in length and contained 13 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes and a control region. All 13 genes were initiated by the start codon ATG, except for nad5 (ATA). Two typical stop codons, TAA and TAG, were present. All of the tRNAs could be folded into typical cloverleaf secondary structures except tRNASer1 and tRNALys, which lacked a DHU stem and complete amino acid acceptor stem, respectively. The control region was 1132?bp in length and contained six AT tandem repeats. According to the gene order of the mitogenome, the 30 analysed Vetigastropoda species could be classified into three types—type I: over half of the studied species were very similar to the gastropod ancestral gene order, and the rearrangements occurred in five tRNAs; type II: eight species were found to be missing several tRNA genes; type III: Fissurellidae, Lepetodrilidae showed a large inverted fragment.  相似文献   
9.
The stability constants for the formation of nickel(II) and cobalt(II) complexes of the ligand [1,4,7]triazecan-9-ol (L) were presented. Antitumor activity of two complexes was reported. Nuclei of [NiL]-stimulated BEL-7402 cells clearly exhibited condensation and break down into chromatin clumps typical of apoptosis. Also it exhibited perturbation effects to cell cycle, and optimal induction of apoptosis was found by Flow-Cytometric analysis. But CoL complex did not exhibit introduction effects to BEL-7402 cells apoptosis; and could not perturb cell cycle. NiL and CuL complexes could cleave supercoiled DNA (pBR 322 DNA) to nicked and linear DNA, and DNA of cells treated with NiL or CuL complex was obviously damaged; while CoL complex only could cleave supercoiled DNA (pBR 322 DNA) to nicked DNA, and DNA of cells treated with CoL complex had no significant difference with control.  相似文献   
10.

Background  

The nematode Caenorhabditis elegans is widely used for the genetic analysis of neuronal cell biology, development, and behavior. Because traditional methods for evaluating behavioral phenotypes are qualitative and imprecise, there is a need for tools that allow quantitation and standardization of C. elegans behavioral assays.  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