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   648篇
  免费   45篇
  国内免费   61篇
化学   574篇
晶体学   1篇
力学   4篇
综合类   61篇
数学   63篇
物理学   51篇
  2024年   1篇
  2023年   13篇
  2022年   62篇
  2021年   65篇
  2020年   26篇
  2019年   26篇
  2018年   23篇
  2017年   34篇
  2016年   27篇
  2015年   27篇
  2014年   34篇
  2013年   41篇
  2012年   30篇
  2011年   31篇
  2010年   23篇
  2009年   28篇
  2008年   41篇
  2007年   26篇
  2006年   22篇
  2005年   23篇
  2004年   22篇
  2003年   13篇
  2002年   14篇
  2001年   7篇
  2000年   14篇
  1999年   10篇
  1998年   10篇
  1997年   11篇
  1996年   8篇
  1995年   6篇
  1994年   7篇
  1993年   3篇
  1992年   5篇
  1991年   4篇
  1990年   3篇
  1989年   8篇
  1987年   1篇
  1986年   1篇
  1983年   1篇
  1981年   2篇
  1979年   1篇
排序方式: 共有754条查询结果,搜索用时 15 毫秒
11.
Four novel terminal modified antisense oligonucleotides (ODNs) were designed, synthesized and tested for their anti-influenza virus activity. Initial biological studies indicated that lipophilic and rimantadin emodificated Flutide exhibited more potent anti-H1N1 activity than Flutide. Among them, lipophilic modificated ODN (Flutide-I) showed the most antiviral activity. The EC50 value of Flutide-I for inhibiting H1N1 induced cytopathic effect (CPE) and H1N1 RNA were respectively (0.26 ± 0.16) μM and (0.11 ± 0.03) μM. The cytotoxicity of these compounds has also been assessed. No significant cytotoxicities were found for any of these compounds with the concentrations up to 20 μM.  相似文献   
12.
Respiratory syncytial virus infection (RSVI) is an acute medical and social problem in many countries globally. Infection is most dangerous for infants under one year old and the elderly. Despite its epidemiological relevance, only two drugs are registered for clinical use against RSVI: ribavirin (approved in a limited number of countries due to side effects) and palivizumab (Synagis), which is intended only for the prevention, but not the treatment, of infection. Currently, various research groups are searching for new drugs against RSV, with three main areas of research: small molecules, polymeric drugs (proteins and peptides), and plant extracts. This review is devoted to currently developed protein and peptide anti-RSV drugs.  相似文献   
13.
Post-translational modifications (PTMs) of adeno-associated virus (AAV) capsid proteins tune and regulate the AAV infective life cycle, which can impact the safety and efficacy of AAV gene therapy products. Many of these PTMs induce changes in protein charge heterogeneity, including deamidation, oxidation, glycation, and glycosylation. To characterize the charge heterogeneity of a protein, imaged capillary isoelectric focusing (icIEF) has become the gold standard method. We have previously reported an icIEF method with native fluorescence detection for denatured AAV capsid protein charge heterogeneity analysis. Although well suited for final products, the method does not have sufficient sensitivity for upstream, low-concentration AAV samples, and lacks the specificity for capsid protein detection in complex samples like cell culture supernatants and cell lysates. In contrast, the combination of icIEF, protein capture, and immunodetection affords significantly higher sensitivity and specificity, addressing the challenges of the icIEF method. By leveraging different primary antibodies, the icIEF immunoassay provides additional selectivity and affords a detailed characterization of individual AAV capsid proteins. In this study, we describe an icIEF immunoassay method for AAV analysis that is 90 times more sensitive than native fluorescence icIEF. This icIEF immunoassay provides AAV stability monitoring, where changes in individual capsid protein charge heterogeneity can be observed in response to heat stress. When applied to different AAV serotypes, this method also provides serotype identity with reproducible quantification of VP protein peak areas and apparent isoelectric point (pI). Overall, the described icIEF immunoassay is a sensitive, reproducible, quantitative, specific, and selective tool that can be used across the AAV biomanufacturing process, especially in upstream process development where complex sample types are often encountered.  相似文献   
14.
The volatile oil of the roots of Cynanchum stauntonii was examined by gas chromatography–mass spectrometry (GC–MS). Thirty-eight constituents were identified. (E,E)-2,4-Decadienal, 3-efhyl-4-methypentanol, 5-pentyl-3H-furan-2-one, (E,Z)-2,4-decadienal and 2(3H)-furanone,dihydro-5-pentyl were found to be the major components. The volatile oil exhibited the activities against influenza virus in vitro (IC50s = 64 μg/ml). In in vivo experiment, it prevented influenza virus-induced deaths in a dose-dependent manner.  相似文献   
15.
A new phenolic derivative, 4-hydroxyphenol-1-O-[6-O-(E)-feruloyl-β-d-glucopyranosyl]-(1→6)-β-d-glucopyranoside (1), and a new terpenylated coumarin, named altissimacoumarin H (2) were identified from the fruit of Ailanthus altissima (Mill.) Swingle (Simaroubaceae), together with ten known compounds (312), including two coumarins and eight phenylpropanoids. Their structures were determined on the basis of chemical method and spectroscopic data. Antiviral effect against Tobacco mosaic virus (TMV) of all the compounds obtained were evaluated using leaf-disc method.  相似文献   
16.
Ebola virus (EBOV) causes zoonotic viral infection with a potential risk of global spread and a highly fatal effect on humans. Till date, no drug has gotten market approval for the treatment of Ebola virus disease (EVD), and this perhaps allows the use of both experimental and computational approaches in the antiviral drug discovery process. The main target of potential vaccines that are recently undergoing clinical trials is trimeric glycoprotein (GP) of the EBOV and its exact crystal structure was used in this structure based virtual screening study, with the aid of consensus scoring to select three possible hit compounds from about 36 million compounds in MCULE’s database. Amongst these three compounds, (5R)-5-[[5-(4-chlorophenyl)-1,2,4-oxadiazol-3-yl]methyl]-N-[(4-methoxyphenyl)methyl]-4,5-dihydroisoxazole-3-carboxamide (SC-2, C21H19ClN4O4) showed good features with respect to drug likeness, ligand efficiency metrics, solubility, absorption and distribution properties and non-carcinogenicity to emerge as the most promising compound that can be optimized to lead compound against the GP EBOV. The binding mode showed that SC-2 is well embedded within the trimeric chains of the GP EBOV with molecular interactions with some amino acids. The SC-2 hit compound, upon its optimization to lead, might be a good potential candidate with efficacy against the EBOV pathogen and subsequently receive necessary approval to be used as antiviral drug for the treatment of EVD.  相似文献   
17.
植物病毒;抑制活性;1-取代苯基-1;4-二氢-6-甲基-4-哒嗪酮-3-酰肼的合成及其抗烟草花叶病毒活性  相似文献   
18.
A series of novel 3,3′-(3,3′-(dihydroxy/hydroxyethane-1,2-diyl)bis(7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine-6,3-diyl))bis(2H-chromen-2-ones) were prepared by the condensation of thiocarbohydrazide with tartaric acid or malic acid followed by various 3-(2-bromoacetyl)-2H-chromen-2-ones in two steps with good yields. All the synthesized compounds were characterized by analytical and spectral (IR, 1H NMR, 13C NMR, and mass) data. These synthesized bis(triazolothiadiazinyl coumarin) compounds were evaluated for broad spectrum of antiviral activity. Among all the tested compounds, compound 5f exhibited antiviral activity against H1N1 virus. The molecular docking studies of these compounds against H1N1 neuraminidase enzyme were performed. The binding affinity and binding values were compared with standard drugs.  相似文献   
19.
从豆科植物豆薯 (Pachyrrhizuserosus,Leguminosae)的种子中分离纯化了一种具有抗植物病毒活性的蛋白质 ,分子量约为 1 5kD。在 2 0 % (w/v)PEG60 0 0 ,0 .1mol/L磷酸盐缓冲液 (pH7.4)条件下得到了可供衍射用的单晶 ,在MarResearchIP上进行了衍射数据收集 ,其衍射能力达 2 .3 。经MarDenzo软件包处理 ,确定其空间群为P2 1 2 1 2 1 ,晶胞参数为 :a =2 8.80 8,b =32 .840 ,c=1 40 .397 。根据Matthews常数估算 ,每个不对称单元含 1个分子。  相似文献   
20.
《Electroanalysis》2018,30(2):220-224
M13 virus (M13) as scaffolds has a major appeal, owing to their mono‐dispersed, fibrillar morphology and engineerable surface reactive sites. Herein we had developed a facile electrocatalyst for energy application. Platinum nanostructures are directly co‐deposited from a wild‐type M13 (or) two different engineered M13 mixed electrolytes onto the ITO electrodes. The engineered M13 with 4E peptides could specifically nucleate Pt precursor thereby enables the efficient growth of teeth‐like structures at the ITO electrode. The electrocatalytic activity of the resulting electrocatalyst toward methanol oxidation in alkaline medium was investigated and found enhanced mass activity (0.321 A/mgPt) relative to the catalyst prepared from wild‐type M13, Y3E peptides engineered M13 and without M13. Our novel electrocatalyst fabrication can be extended to other metal and metal oxides and its application might be useful to develop novel clean and green energy generating and storage materials.  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