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   974篇
  免费   70篇
  国内免费   17篇
电工技术   3篇
综合类   22篇
化学工业   383篇
金属工艺   8篇
机械仪表   18篇
建筑科学   22篇
能源动力   10篇
轻工业   427篇
水利工程   1篇
石油天然气   14篇
无线电   14篇
一般工业技术   47篇
冶金工业   47篇
原子能技术   3篇
自动化技术   42篇
  2024年   26篇
  2023年   46篇
  2022年   197篇
  2021年   170篇
  2020年   35篇
  2019年   47篇
  2018年   33篇
  2017年   33篇
  2016年   40篇
  2015年   43篇
  2014年   44篇
  2013年   43篇
  2012年   31篇
  2011年   36篇
  2010年   27篇
  2009年   20篇
  2008年   20篇
  2007年   25篇
  2006年   16篇
  2005年   20篇
  2004年   13篇
  2003年   13篇
  2002年   18篇
  2001年   4篇
  2000年   6篇
  1999年   4篇
  1998年   8篇
  1997年   3篇
  1996年   2篇
  1995年   3篇
  1994年   8篇
  1993年   2篇
  1992年   11篇
  1991年   6篇
  1990年   1篇
  1989年   1篇
  1987年   4篇
  1986年   1篇
  1984年   1篇
排序方式: 共有1061条查询结果,搜索用时 15 毫秒
91.
92.
93.
With the progress of sequencing technologies, an ever-increasing number of variants of unknown functional and clinical significance (VUS) have been identified in both coding and non-coding regions of the main Breast Cancer (BC) predisposition genes. The aim of this study is to identify a mutational profile of coding and intron-exon junction regions of 12 moderate penetrance genes (ATM, BRIP1, CDH1, CHEK2, NBN, PALB2, PTEN, RAD50, RAD51C, RAD51D, STK11, TP53) in a cohort of 450 Italian patients with Hereditary Breast/Ovarian Cancer Syndrome, wild type for germline mutation in BRCA1/2 genes. The analysis was extended to 5′UTR and 3′UTR of all the genes listed above and to the BRCA1 and BRCA2 known regulatory regions in a subset of 120 patients. The screening was performed through NGS target resequencing on the Illumina platform MiSeq. 8.7% of the patients analyzed is carriers of class 5/4 coding variants in the ATM (3.6%), BRIP1 (1.6%), CHEK2 (1.8%), PALB2 (0.7%), RAD51C (0.4%), RAD51D (0.4%), and TP53 (0.2%) genes, while variants of uncertain pathological significance (VUSs)/class 3 were identified in 9.1% of the samples. In intron-exon junctions and in regulatory regions, variants were detected respectively in 5.1% and in 32.5% of the cases analyzed. The average age of disease onset of 44.4 in non-coding variant carriers is absolutely similar to the average age of disease onset in coding variant carriers for each proband’s group with the same cancer type. Furthermore, there is not a statistically significant difference in the proportion of cases with a tumor onset under age of 40 between the two groups, but the presence of multiple non-coding variants in the same patient may affect the aggressiveness of the tumor and it is worth underlining that 25% of patients with an aggressive tumor are carriers of a PTEN 3′UTR-variant. This data provides initial information on how important it might be to extend mutational screening to the regulatory regions in clinical practice.  相似文献   
94.
Amyotrophic Lateral Sclerosis (ALS), neurodegenerative motor neuron disorder is characterized as multisystem disease with important contribution of genetic factors. The etiopahogenesis of ALS is not fully elucidate, but the dominant theory at present relates to RNA processing, as well as protein aggregation and miss-folding, oxidative stress, glutamate excitotoxicity, inflammation and epigenetic dysregulation. Additionally, as mitochondria plays a leading role in cellular homeostasis maintenance, a rising amount of evidence indicates mitochondrial dysfunction as a substantial contributor to disease onset and progression. The aim of this review is to summarize most relevant findings that link genetic factors in ALS pathogenesis with different mechanisms with mitochondrial involvement (respiratory chain, OXPHOS control, calcium buffering, axonal transport, inflammation, mitophagy, etc.). We highlight the importance of a widening perspective for better understanding overlapping pathophysiological pathways in ALS and neurodegeneration in general. Finally, current and potentially novel therapies, especially gene specific therapies, targeting mitochondrial dysfunction are discussed briefly.  相似文献   
95.
96.
Six novel linear peptides, named “rhabdopeptides”, have been identified in the entomopathogenic bacterium Xenorhabdus nematophila after the discovery of the corresponding rdp gene cluster by using a promoter trap strategy for the detection of insect‐inducible genes. The structures of these rhabdopeptides were deduced from labeling experiments combined with detailed MS analysis. Detailed analysis of an rdp mutant revealed that these compounds participate in virulence towards insects and are produced upon bacterial infection of a suitable insect host. Furthermore, two additional rhabdopeptide derivatives produced by Xenorhabdus cabanillasii were isolated, these showed activity against insect hemocytes thereby confirming the virulence of this novel class of compounds.  相似文献   
97.
不同实验条件下差异表达基因(DEGs)的识别是微阵列数据分析的主要目标之一,针对分析结果中具有高排名的基因往往表现出较低差异表达水平的缺点,提出了一种基于简单统计排名模型的差异表达基因识别算法MRP(Matrix rank product)。算法可直接处理基因芯片原始数据,排除了数据预处理方法对算法的干扰;另外,通过对基因芯片数据形成的矩阵进行整体排序计算,得到具有高准确度的差异表达性排名结果。  相似文献   
98.
侯慧  李春 《化工进展》2016,35(6):1837-1844
提高生物基产品的产量和生产效率是生物制造发展的目标。由于微生物具有生长快、营养要求简单和基因操作简便等特点,常用作生物基产品制造过程中的底盘宿主,因此,产品制造过程中微生物细胞的生长与调控尤为重要,其生长调控会直接或间接地影响生物基产品的合成效率。微生物的生长不仅受外界环境如温度、溶氧量、pH等的影响,而且还受微生物本身的生长与调控机制如细胞分裂调控、必需基因表达调控、程序化死亡等的影响。本文综述了利用分子生物学、合成生物学和系统生物学等方法对微生物细胞生长和分裂过程进行分子调控,以提高生物反应速率和目标产物的产量,为化工、食品、生物医药以及环境保护等领域构建高效的生物制造工艺提供新思路。  相似文献   
99.
Aberration during the development of the central nervous system (CNS) due to environmental factors underlies a variety of adverse developmental outcomes. Paraquat (PQ) is a widely studied neurotoxicant that perturbs the normal structure/function of adult CNS. Yet, the impacts of PQ exposure on the developing CNS remain unclear. miRNAs represent a class of small non-coding RNA molecules involved in the regulation of neural development. Thus in the present study, we analyzed the impacts of PQ on the miRNome of human neural progenitor cells (hNPCs) during proliferation by using the Exiqon miRCURY™ LNA Array. A total of 66 miRNAs were identified as differentially expressed in proliferating hNPCs upon PQ treatment. miRTarBase prediction identified 1465 mRNAs, including several genes (e.g., nestin, sox1, ngn1) previously proved to be associated with the neural proliferation and differentiation, as target genes of PQ-induced differentially expressed miRNAs. The database for annotation, visualization and integrated discovery (DAVID) bioinformatics analysis showed that target genes were enriched in regulation of cell proliferation and differentiation, cell cycle and apoptosis as well as tumor protein 53 (p53), Wnt, Notch and mitogen-activated protein kinases (MAPK) signaling pathways (p < 0.001). These findings were confirmed by real-time RT-PCR. Based on our results we conclude that PQ-induced impacts on the miRNA profiling of hNPCs undergoing proliferation may underlie the developmental neurotoxicity of PQ.  相似文献   
100.
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