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   89篇
  免费   13篇
  国内免费   7篇
化学   71篇
晶体学   1篇
力学   15篇
数学   6篇
物理学   16篇
  2023年   6篇
  2022年   8篇
  2021年   10篇
  2020年   9篇
  2019年   6篇
  2018年   8篇
  2017年   7篇
  2016年   8篇
  2015年   4篇
  2014年   4篇
  2013年   5篇
  2012年   6篇
  2011年   5篇
  2010年   7篇
  2008年   3篇
  2007年   3篇
  2006年   3篇
  2005年   1篇
  1996年   2篇
  1993年   1篇
  1988年   1篇
  1987年   1篇
  1971年   1篇
排序方式: 共有109条查询结果,搜索用时 17 毫秒
81.
We present a solution framework based on discrete-event simulation and enhanced robust design technique to address a multi-response optimization problem inherent in logistics management. The objective is to design a robust configuration for a cross-docking distribution center so that the system is insensitive to the disturbances of supply uncertainty, and provides steady parts supply to downstream assembly plants. In the proposed approach, we first construct a simulation model using factorial design and central composite design (CCD), and then identify the models that best describe the relationship between the simulation responses and system factors. We employ the response surface methodology (RSM) to identify factor levels that would maximize system potential.  相似文献   
82.
Pentaindenocorannulene (C50H20 , 1 ), a deep bowl polynuclear aromatic hydrocarbon, accepts 4 electrons, crystallizes in columnar bowl‐in‐bowl assemblies and forms a nested C60@ 1 2 complex. Spectra, structures and computations are presented.  相似文献   
83.
Pentaindenocorannulene (C50H20 , 1 ), a deep bowl polynuclear aromatic hydrocarbon, accepts 4 electrons, crystallizes in columnar bowl‐in‐bowl assemblies and forms a nested C60@ 1 2 complex. Spectra, structures and computations are presented.  相似文献   
84.
Chemically highly stable MOFs incorporating multiple functionalities are of great interest for applications under harsh environments. Herein, we presented a facile one‐pot synthetic strategy to incorporate multiple functionalities into stable Zr‐MOFs from mixed ligands of different geometry and connectivity. Via our strategy, tetratopic tetrakis(4‐carboxyphenyl)porphyrin (TCPP) ligands were successfully integrated into UiO‐66 while maintaining the crystal structure, morphology, and ultrahigh chemical stability of UiO‐66. The amount of incorporated TCPP is controllable. Through various combinations of BDC derivatives and TCPP, 49 MOFs with multiple functionalities were obtained. Among them, MOFs modified with FeTCPPCl were demonstrated to be catalytically active for the oxidation of ABTS. We anticipate our strategy to provide a facile route to introduce multiple functionalities into stable Zr‐MOFs for a wide variety of potential applications.  相似文献   
85.
Small-molecule subcellular organelle-targeting theranostic probes are crucial for early disease diagnosis and treatment. The imaging window of these molecules is mainly focused on the visible and near-infrared region (below ∼900 nm) which limits the tissue penetration depth and therapeutic effects. Herein, a novel NIR-II small-molecule probe H4–PEG-Glu with a thiopyrylium cation was synthesized. H4–PEG-Glu not only can quickly and effectively image mitochondria in acute myeloid leukemia (AML) cells, and induce G0/G1 phase arrest by the intrinsic mitochondrial apoptosis pathway w/o irradiation, but also exhibit moderate cytotoxicity against AML cancer cells in a dose dependent-manner without laser irradiation. The THP-1 cells treated with H4–PEG-Glu upon NIR laser irradiation showed enhanced chemo- and photothermal therapy (CPTT) with 93.07% ± 6.43 apoptosis by Annexin V staining. Meanwhile, H4–PEG-Glu displayed high synergistic CPTT effects in vivo, as well as specific NIR-II tumor imaging in AML patient derived PDX mouse models for the first time. Our work lays down a solid foundation for designing small-molecule NIR-II mitochondria-selective theranostic probes.

Small-molecule subcellular organelle-targeting theranostic probes are crucial for early disease diagnosis and treatment.  相似文献   
86.
Both surface microstructure and low surface energy modification play a vital role in the preparation of superhydrophobic surfaces. In this study, a safe and simple electrochemical method was developed to fabricate superhydrophobic surfaces of Zr-based metallic glasses with high corrosion resistance. First, micro–nano composite structures were generated on the surface of Zr-based metallic glasses by electrochemical etching in NaCl solution. Next, stearic acid was used to decrease surface energy. The effects of electrochemical etching time on surface morphology and wettability were also investigated through scanning electron microscopy and contact angle measurements. Furthermore, the influence of micro–nano composite structures and roughness on the wettability of Zr-based metallic glasses was analysed on the basis of the Cassie–Baxter model. The water contact angle of the surface was 154.3° ± 2.2°, and the sliding angle was <5°, indicating good superhydrophobicity. Moreover, the potentiodynamic polarisation test and electrochemical impedance spectroscopy suggested excellent corrosion resistance performance, and the inhibition efficiency of the superhydrophobic surface reached 99.6%. Finally, the prepared superhydrophobic surface revealed excellent temperature-resistant and self-cleaning properties.  相似文献   
87.
本文采用直流磁控溅射分层溅射制备了氧化铟锡(ITO)/银(Ag)/ITO多层复合薄膜。系统研究了溅射温度对ITO/Ag/ITO多层复合薄膜的结构和光电性能影响。采用ITO(m(In2O3)∶m(SnO2)=9∶1;直径60 mm)靶材和Ag(纯度99.999%;直径60 mm)靶材分层溅射,使ITO薄膜和Ag薄膜依次沉积在钠-钙玻璃基片上。结果表明,溅射温度对该薄膜的形貌和结构具有显著的影响。在中间Ag薄膜和顶层ITO薄膜的溅射温度均为120 ℃时,薄膜表面晶粒形貌由类球形转变为菱形,此时薄膜方阻为3.68 Ω/Sq,在488 nm处透射率为88.98%,且品质因数为0.03 Ω-1,实现了低方阻高可见光透射率ITO/Ag/ITO多层复合薄膜的制备。  相似文献   
88.
89.
We report a single‐molecule mechanistic investigation into 2‐cyanobenzothiazole (CBT) chemistry within a protein nanoreactor. When simple thiols reacted reversibly with CBT, the thioimidate monoadduct was approximately 80‐fold longer‐lived than the tetrahedral bisadduct, with important implications for the design of molecular walkers. Irreversible condensation between CBT derivatives and N‐terminal cysteine residues has been established as a biocompatible reaction for site‐selective biomolecular labeling and imaging. During the reaction between CBT and aminothiols, we resolved two transient intermediates, the thioimidate and the cyclic precursor of the thiazoline product, and determined the rate constants associated with the stepwise condensation, thereby providing critical information for a variety of applications, including the covalent inhibition of protein targets and dynamic combinatorial chemistry.  相似文献   
90.
建立了QuEChERS结合超高效液相色谱-四极杆静电场轨道离子阱质谱测定鱼肉中15种降血脂药残留量的方法。样品前处理采用优化的QuEChERS法,通过响应面法优化了吸附剂材料乙二胺-N-丙基硅烷(PSA)(20、60、100、140和180 mg)、C18(40、100、160、220和280 mg)及乙酸钠(0.2、0.6、1.0、1.4和1.8 g)的用量。液相色谱采用XBridge-C18色谱柱(100 mm×2.1 mm,3.5 μm),以乙腈-0.1%(v/v)甲酸水溶液(含1.5 mmol/L乙酸铵)为流动相进行梯度洗脱,采用加热电喷雾电离(HESI)源,在正、负离子同时检测模式下以全扫描(full-MS)和二级质谱扫描(dd-MS2)方式对目标物进行定性和定量分析。15种降血脂药在各自范围内线性关系良好,相关系数(R2)大于0.99;检出限(LOD,S/N=3)和定量限(LOQ,S/N=10)分别为0.2~1.0 μg/kg和0.3~3.1 μg/kg;鱼肉样品中15种降血脂药在LOQ、2倍LOQ和10倍LOQ水平下的加标回收率为76.4%~116.0%,日内日精密度为1.0%~7.9%,日间精密度为1.7%~18.4%。该法前处理简单,灵敏度高,回收率高,适用于鱼肉中降血脂药的检测。  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