全文获取类型
收费全文 | 300篇 |
免费 | 74篇 |
国内免费 | 45篇 |
专业分类
化学 | 335篇 |
晶体学 | 3篇 |
综合类 | 2篇 |
物理学 | 79篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 30篇 |
2020年 | 50篇 |
2019年 | 33篇 |
2018年 | 25篇 |
2017年 | 24篇 |
2016年 | 36篇 |
2015年 | 32篇 |
2014年 | 23篇 |
2013年 | 24篇 |
2012年 | 12篇 |
2011年 | 21篇 |
2010年 | 9篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1990年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有419条查询结果,搜索用时 421 毫秒
91.
在全电子相对论BVP86/DNP水平下对CO在Au55,Ag55和Cu55团簇上的吸附进行了比较研究,并考察了电荷对吸附的影响.计算结果表明,CO在Au55团簇上吸附能最大,其次为Cu55团簇,最弱的为Ag55团簇.团簇电荷对C—O键活化和CO与团簇表面原子成键影响较小.金团簇的电荷对吸附能影响较大,而银和铜团簇的电荷对吸附能影响较小.CO吸附到团簇上导致团簇上电子向CO转移.C—O键活化强度与吸附位置密切相关,其中孔位吸附导致C—O键活化程度最大,最弱的为顶位吸附.CO在金团簇上吸附具有较好选择性,而在银和铜团簇上吸附无选择性. 相似文献
92.
Zhenzhen Huang Yu Tao Dr. Fang Pu Prof. Dr. Jinsong Ren Prof. Dr. Xiaogang Qu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(21):6663-6669
A DNA‐encoding strategy is reported for the programmable regulation of the fluorescence properties of silver nanoclusters (AgNCs). By taking advantage of the DNA‐encoding strategy, aqueous AgNCs were used as signal transducers to convert DNA inputs into fluorescence outputs for the construction of various DNA‐based logic gates (AND, OR, INHIBIT, XOR, NOR, XNOR, NAND, and a sequential logic gate). Moreover, a biomolecular keypad that was capable of constructing crossword puzzles was also fabricated. These AgNC‐based logic systems showed several advantages, including a simple transducer‐introduction strategy, universal design, and biocompatible operation. In addition, this proof of concept opens the door to a new generation of signal transducer materials and provides a general route to versatile biomolecular logic devices for practical applications. 相似文献
93.
《Analytical letters》2012,45(4):647-658
A simple and label-free fluorescent assay for the sensitive determination of biological thiols was developed using Au@Ag nanoclusters. The sensing approach was based on the strong affinity of thiols to silver on the surface of the nanoclusters. In the presence of thiol-containing amino acids, the fluorescence of the Au@Ag nanoclusters was quenched due to the formation of a non-fluorescent coordination complex via the robust Ag-S bond, which allowed the determination of thiol-containing amino acids in a very simple and rapid way. Under the optimal conditions, an excellent linear relationship was present due to quenching of the Au@Ag nanoclusters over cysteine concentrations between 20 nM and 80 µM with a low detection limit of 5.87 nM. Glutathione was determined between 2 µM and 70 µM with a detection limit of 1.01 µM. In addition, the results reveal that the fluorescent assay has excellent selectivity toward thiol-containing amino acids compared to non-thiol containing amino acids. Moreover, the assay was successfully used to determine cysteine in human plasma, and thus Au@Ag nanoclusters are a suitable fluorescent probe for biological applications. 相似文献
94.
利用真空沉积方法在高定向石墨(HOPG)基底上直接制备了粒径分布较小的金纳米粒子.超高真空扫描隧道显微镜(STM)研究发现,在74℃退火后,表观直径为2.5?nm的金纳米粒子在HOPG基底上形成了排列均匀的准一维纳米粒子链,并且此金纳米粒子链结构稳定.在122℃退火后,不同粒径的金纳米粒子在HOPG基底表面上聚合长大形成了准一维金纳米线.这一发现为制备由金粒子组成的有序纳米结构开辟了探索途径. 相似文献
95.
96.
97.
Dr. Tokuhisa Kawawaki Yukari Imai Daiki Suzuki Shun Kato Ibuki Kobayashi Taiyo Suzuki Ryo Kaneko Dr. Sakiat Hossain Prof. Yuichi Negishi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(69):16150-16193
Metal nanoclusters (NCs) have a particle size of about one nanometer, which makes them the smallest unit that can give a function to a substance. In addition, metal NCs possess physical and chemical properties that are different from those of the corresponding bulk metals. Metal NCs with such characteristics are expected to be important for use in nanotechnology. Research on the precise synthesis of metal NCs and elucidation of their physical/chemical properties and functions is being actively conducted. When metal NCs are alloyed, it is possible to obtain further various electronic and geometrical structures and functions. Thus, research on alloy NCs has become a hot topic in the study of metal NCs and the number of publications on alloy NCs has increased explosively in recent years. Such publications have provided much insight into the effects of alloying on the electronic structure and function of metal NCs. However, the rapid increase in knowledge has made it difficult for researchers (especially those new to the field) to grasp all of it. Therefore, in this review, we summarize the reported chemical composition, geometrical structure, electronic structure, and physical and chemical properties of Aun−xMx(SR)m, Agn−xMx(SR)m, Aun−xMx(PR3)l(SR)m, and Agn−xMx(PR3)l(SR)m (Au=gold, Ag=silver, M=heteroatom, PR3=phosphine, and SR=thiolate) NCs. This review is expected to help researchers understand the characteristics of alloy NCs and lead to clear design guidelines to develop new alloy NCs with intended functions. 相似文献
98.
Ting Liu Prof. Xin Huang Lingyun Zhao Zhongqing Xiao Zengbei Li Yi Xin Shanshan Yang Di Guo Wenfei Zhao Dr. Yang Mi Prof. Hongyun Li 《ChemistryOpen》2021,10(9):882-888
Lung cancer is the leading cause of cancer deaths worldwide and most cancer patients receiving conventional chemotherapy suffer from severe side effects due to the non-selective effects of chemotherapeutic drugs on normal cells. Targeted nanomaterials can obtain excellent accumulation at the tumor site through their active or passive targeting mechanisms, thereby reducing the toxicity of the drugs in various ways. In this study, hyaluronic acid (HA) which could specifically bind to CD44 on the surface of tumor cells, was used to modify amine-caged platinum nanoclusters (Pt NCs-NH2) to obtain targeting HA-Pt NCs-NH2. Based on the differential expression of CD44 on the surface of three lung cells (non-small cell lung cancer cell H1299, small cell lung cancer cell H446, and embryonic lung fibroblast HFL1), HA-Pt NCs-NH2 can differentially enter the three cells and achieve their targeting of non-small cell lung cancer cell (NSCLC) cells. Pt NCs significantly inhibited the proliferation, migration and invasion of NSCLC cells and induced their apoptosis in comparison of classical cisplatin and carboplatin, showing a bright future in early diagnosis and treatment of NSCLC. 相似文献
99.
Xue Ji 《Molecular physics》2020,118(16)
In this study, the reactivity and electronic sensitivity of the Be12O12, Mg12O12, and Zn12O12 nanoclusters were investigated for 6-thioguanine (TG) anticancer drug using density functional theory calculations at the gas phase and aqueous solution. Our results show that the electronic properties of Mg12O12 and Zn12O12 nanoclusters are significantly sensitive to the presence of TG and the nanoclusters may be a promising candidate for adsorption of this drug. The results show that all complexes are energetically favourable, especially in the aqueous phase. Also, our ultraviolet–visible results show that the electronic spectra of TG/(MO)12 complexes exhibit a blue shift toward lower wavelengths (higher energies). In order to go further and gain insight into the binding features of considered (MO)12 nanoclusters with TG drug, the Atoms in Molecules analysis was performed. Consequently, the results demonstrated that the Mg12O12 and Zn12O12 nanoclusters could be used as potential carriers for the delivery of TG drug. The results represented that the Mg12O12 and Zn12O12 nanoclusters could be used as potential carriers for delivery of 6-thioguanine drug in the nanomedicine domain. 相似文献
100.
Dr. Srestha Basu Archismita Hajra Chirantan Gayen Prof. Anumita Paul 《Chemphyschem》2020,21(8):809-813
Herein, we report discrimination of dicarboxylic acids – fumaric acid (FA) and maleic acid (MA) – exhibiting geometrical isomerism, using nanoclusters based luminescent probe having excitation under broad day light. The luminescent probe was designed via complexation reaction between zinc ions and ligands (mercaptopropioinc acid; MPA) stabilizing the gold nanoclusters. This resulted in formation of nanoaggregates exhibiting bright green luminescence upon excitation at 450 nm capable of discriminating between FA and MA upto nanomolar level. The basis of discrimination has been attributed to deprotonation of FA and MA following interaction with MPA moieties present on the surface of the nanoaggregates and being governed by the stability of the respective conjugate base of the geometrical isomers of the dicarboxylic acids. As a consequence of different extent of deprotonation of FA and MA upon interaction with the cluster aggregates, different effect on the luminescence of the aggregates was observed, thus enabling discernible fluorimetric discrimination between FA and MA under visible light excitation. 相似文献