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   19篇
  免费   0篇
  国内免费   5篇
化学   14篇
综合类   1篇
数学   3篇
物理学   6篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   1篇
  2014年   3篇
  2013年   1篇
  2012年   1篇
  2011年   4篇
  2010年   1篇
  2009年   1篇
  2004年   1篇
  1999年   3篇
  1993年   1篇
排序方式: 共有24条查询结果,搜索用时 140 毫秒
1.
本研究选取了分化型甲状腺癌(DTC)患者106例为甲状腺癌组,同期106例甲状腺腺瘤患者为甲状腺腺瘤组,检测比较了两组患者的超声弹性成像参数(弹性比值、蓝色面积比值)、血清中期因子(midkine,MK)、血管内皮生长因子(VEGF)水平.研究结果发现,弹性比值、蓝色面积比值、血清MK和VEGF水平与DTC患者淋巴结转...  相似文献   
2.
在多标度人工色模型框架下计算了荷电PG玻色子  相似文献   
3.
1,3,4,6-tetramethylpiperazine-2,5-dione was synthesized, and the crystal structure was characterized by single-crystal X-ray diffraction method, vibrational spectral measurements were obtained by Fourier transform infrared spectroscopy and Fourier transform Raman spectroscopy. The measurements agree well with the calculated geometrical structure and harmonic vibrational wavenumbers (usingab initio and density functional theory Becke’s three parameters hybrid method with the Lee, Yang, and Parr non-local functions methods with 6-311G and 6-311G** basis sets).  相似文献   
4.
In this paper, we consider the zero-norm minimization problem with linear equation and nonnegativity constraints. By introducing the concept of generalized Z-matrix for a rectangular matrix, we show that this zero-norm minimization with such a kind of measurement matrices and nonnegative observations can be exactly solved via the corresponding p-norm minimization with p in the open interval from zero to one. Moreover, the lower bound of sample number for exact recovery is allowed to be the same as the sparsity of the original image or signal by the underlying zero-norm minimization. A practical application in communications is presented, which satisfies the generalized Z-matrix recovery condition.  相似文献   
5.
Mimicking the structures and functions of cells to create artificial organelles has spurred the development of efficient strategies for production of hollow nanoreactors with biomimetic catalytic functions. However, such structure are challenging to fabricate and are thus rarely reported. We report the design of hollow nanoreactors with hollow multishelled structure (HoMS) and spatially loaded metal nanoparticles. Starting from a molecular-level design strategy, well-defined hollow multishelled structure phenolic resins (HoMS-PR) and carbon (HoMS-C) submicron particles were accurately constructed. HoMS-C serves as an excellent, versatile platform, owing to its tunable properties with tailored functional sites for achieving precise spatial location of metal nanoparticles, internally encapsulated (Pd@HoMS-C) or externally supported (Pd/HoMS-C). Impressively, the combination of the delicate nanoarchitecture and spatially loaded metal nanoparticles endow the pair of nanoreactors with size–shape-selective molecular recognition properties in catalytic semihydrogenation, including high activity and selectivity of Pd@HoMS-C for small aliphatic substrates and Pd/HoMS-C for large aromatic substrates. Theoretical calculations provide insight into the pair of nanoreactors with distinct behaviors due to the differences in energy barrier of substrate adsorption. This work provides guidance on the rational design and accurate construction of hollow nanoreactors with precisely located active sites and a finely modulated microenvironment by mimicking the functions of cells.  相似文献   
6.
计算了人工色荷电PG玻色子π±1和π±8对稀有衰变过程B→η′Xs中η′单举产率的贡献.计算结果表明:QCD胶子反常和人工色新物理贡献能够提供较大的分枝比,以解释CLEO实验结果.  相似文献   
7.
基于非离子表面活性剂Triton X-100,以浊点萃取结合荧光光度法测定水中的苯酚,考察影响浊点萃取的各种因素。在pH=3.0的磷酸氢二钠-磷酸二氢钾缓冲溶液中,采用2.0mL Triton X-100(5%)、82℃平衡温度、8min平衡时间的条件下,苯酚被萃取到Triton X-100表面活性剂相与水相分开,用于环境水样中苯酚的测定,结果令人满意。  相似文献   
8.
食品包装中的化学问题   总被引:1,自引:0,他引:1  
从化学的角度考察塑料包装、金属包装、纸包装和玻璃包装等传统的食品包装,寻找影响食品包装安全的因素以及食品包装的发展方向——开发新型包装材料,实现绿色包装。  相似文献   
9.
10.
从新疆吐鲁番盆地分离出十二株嗜热(生长温度为:25℃~73℃,最适温度为:45℃~60℃)、革兰氏阳性芽孢杆菌,经鉴定为Bacillus spp。  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