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   396篇
  免费   11篇
  国内免费   19篇
化学   314篇
晶体学   2篇
力学   5篇
数学   13篇
物理学   92篇
  2023年   4篇
  2022年   3篇
  2021年   15篇
  2020年   8篇
  2019年   12篇
  2018年   7篇
  2017年   10篇
  2016年   10篇
  2015年   9篇
  2014年   8篇
  2013年   24篇
  2012年   14篇
  2011年   22篇
  2010年   10篇
  2009年   17篇
  2008年   12篇
  2007年   10篇
  2006年   13篇
  2005年   13篇
  2004年   12篇
  2003年   5篇
  2002年   6篇
  2001年   4篇
  2000年   6篇
  1998年   5篇
  1996年   8篇
  1995年   7篇
  1994年   3篇
  1993年   5篇
  1992年   5篇
  1991年   6篇
  1989年   5篇
  1988年   3篇
  1987年   7篇
  1986年   6篇
  1985年   4篇
  1984年   3篇
  1982年   3篇
  1981年   8篇
  1980年   8篇
  1979年   4篇
  1978年   12篇
  1977年   7篇
  1975年   6篇
  1974年   3篇
  1973年   6篇
  1972年   4篇
  1967年   3篇
  1954年   3篇
  1904年   4篇
排序方式: 共有426条查询结果,搜索用时 15 毫秒
411.
Based on the active site of lanosterol 14α-demethylase of azole antifungal agents,sixteen 1-(1H-1,2,4-triazole-1-yl)- 2-(2,4- difluorophenyl)-3-(N-n-butyl-N-1-substitutedbenzyl-4-methylene-1H-1,2,3-triazole)-2-propanols have been designed,synthesized and evaluated as antifungal agents.Results of preliminary antifungal tests against eight human pathogenic fungi in vitro showed that some of the compounds exhibited excellent activities with broad spectrum.  相似文献   
412.
A new two-photon absorption compound,2-{4-((dicyanomethylidene-5,5-dimethylcyclohexl)vinyl]phenyl}imidazo[4,5- f][l,10]phenanthroline(DDVPIP),was synthesized and characterized.The one-photon excited fluorescence(OPEF) and two-photon excited fluorescence(TPEF) of DDVPIP are sensitive to the acid/base of the solution,which arc enhanced in basic solution but weakened in acidic solution.Charge-transfer(CT) states of DDVPIP were calculated through theory methods to explain its acid/ base-sensitive fluorescent properties.  相似文献   
413.
Elemental sulfur - both in the solid, liquid, and gaseous state - shows highly unusual physical and chemical properties not matched by any other element. The reason for this unique behavior is the formation of molecules of different size -from S2 to S6, S7, and S8 up to macromolecules („S,”︁) - every size is possible. Which mixture is obtained depends on the temperature and other reaction conditions. These findings are important for the understanding of elemental sulfur produced industrially in huge quantities, certain astonishing observations made with bacteria that oxidize sulfur, the Stretford process for sulfur production, and the sulfur covering Ios surface.  相似文献   
414.
415.
以TiO2和炭黑为反应物,TiC为添加物,通过反应烧结法制备出多孔TiC陶瓷.研究了TiC的添加量对晶粒大小、孔径尺寸、开气孔率及抗弯强度的影响.研究结果表明:随着TiC的添加量从0;增大到100;,反应生成TiC的粒径从0.17μm增大到0.71μm,孔径尺寸从0.15μm增大到1.51μm,开气孔率从78;持续降到38;,抗弯强度先增加后减小,添加量为80;时最高(86 MPa).TiC生长机理主要是由于添加的TiC使TiO2周围的碳含量减少,从而导致反应生成TiC的熔点降低,扩散能力提高,晶粒粒径增大.  相似文献   
416.
417.
Responsive polymer systems have the ability to change properties or behavior in response to external stimuli. The properties of responsive polymer systems can be fine-tuned by adjusting the stimuli, enabling tailored responses for specific applications. These systems have applications in drug delivery, biosensors, tissue engineering, and more, as their ability to adapt and respond to dynamic environments leads to improved performance. However, challenges such as synthesis complexity, sensitivity limitations, and manufacturing issues need to be addressed for successful implementation. In our review, we provide a comprehensive summary on stimuli-responsive polymer systems, delving into the intricacies of their mechanisms and actions. Future developments should focus on precision medicine, multifunctionality, reversibility, bioinspired designs, and integration with advanced technologies, driving the dynamic growth of sensitive polymer systems in biomedical applications.  相似文献   
418.
Molecular Diversity - An effective technique for one-stage synthesis of new polycyclic nitrogen-containing compounds has been developed. The procedure involves refluxing mixtures of camphoric acid...  相似文献   
419.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.  相似文献   
420.
A cyclodextrin‐peptide hybrid (17NNβ) bearing two naphthalene units in the peptide side chain has been designed and synthesized as a novel chemosensor molecule. Circular dichroism study of the compound revealed that the peptide has α‐helix structure with a helix content of 41%. The peptide revealed both monomer and excimer emission and the intensity of the excimer emission increased while that of the monomer emission decreased upon addition of the guest compound. This behavior was observed for various guest molecules, suggesting that the system can be used for detecting molecules in aqueous solution.  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