全文获取类型
收费全文 | 227篇 |
免费 | 21篇 |
专业分类
化学 | 191篇 |
晶体学 | 2篇 |
力学 | 1篇 |
数学 | 15篇 |
物理学 | 39篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 8篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 21篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 15篇 |
2012年 | 27篇 |
2011年 | 22篇 |
2010年 | 14篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 18篇 |
2006年 | 15篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有248条查询结果,搜索用时 62 毫秒
11.
Nataliya Zelisko Dmytro Atamanyuk Olexandr Vasylenko Andriy Bryhas Vasyl Matiychuk Andrzej Gzella Roman Lesyk 《Tetrahedron》2014
Various novel thiopyrano[2,3-d][1,3]thiazol-2-one-6-carboxylic acids derivatives were synthesized in 54–86% yields via hetero-Diels–Alder reactions and related acylation-based tandem processes of 5-arylidene-4-thioxo-2-thiazolidinones with crotonic, propiolic, and cynnamic acids derivatives. Stereo- and regioselectivity of cycloaddition were investigated. 相似文献
12.
Ohorodnik Yulia M. Alexander Sikalov A. Khomenko Dmytro M. Doroshchuk Roman O. Raspertova Ilona V. Shova Sergiu Babak Maria V. Lampeka Rostyslav D. 《Transition Metal Chemistry》2022,47(6):213-221
Transition Metal Chemistry - The structures of new p-cymene Ru(II) complexes with 2-(1-methyl-1H-1,2,4-triazol-3-yl)pyridine and 2-(1-methyl-1H-1,2,4-triazol-5-yl)pyridine were established based on... 相似文献
13.
Dmytro Makarov András Telek Tobias Becker Marie-Kristin von Wrisberg Sabine Schneider Pavel Kielkowski 《Journal of mass spectrometry : JMS》2022,57(3):e4812
The identification and quantification of modified peptides are critical for the functional characterization of post-translational protein modifications (PTMs) to elucidate their biological function. Nowadays, quantitative mass spectrometry coupled with various bioinformatic pipelines has been successfully used for the determination of a wide range of PTMs. However, direct characterization of low abundant protein PTMs in bottom-up proteomic workflow remains challenging. Here, we present the synthesis and evaluation of tandem mass spectrometry tags (TMT) which are introduced via click-chemistry into peptides bearing alkyne handles. The fragmentation properties of the two mass tags were validated and used for screening in a model system and analysis of AMPylated proteins. The presented tags provide a valuable tool for diagnostic peak generation to increase confidence in the identification of modified peptides and potentially for direct peptide-PTM quantification from various experimental conditions. 相似文献
14.
Sara Janowska Dmytro Khylyuk Anna Bielawska Anna Szymanowska Agnieszka Gornowicz Krzysztof Bielawski Jarosaw Noworl Sawomir Mandziuk Monika Wujec 《Molecules (Basel, Switzerland)》2022,27(6)
We designed and synthesized the 1,3,4-thiadiazole derivatives differing in the structure of the substituents in C2 and C5 positions. The cytotoxic activity of the obtained compounds was then determined in biological studies using MCF-7 and MDA-MB-231 breast cancer cells and normal cell line (fibroblasts). The results showed that in both breast cancer cell lines, the strongest anti-proliferative activity was exerted by 2-(2-trifluorometylophenylamino)-5-(3-methoxyphenyl)-1,3,4-thiadiazole. The IC50 values of this compound against MCF-7 and MDA-MB-231 breast cancer cells were 49.6 µM and 53.4 µM, respectively. Importantly, all new compounds had weaker cytotoxic activity on normal cell line than on breast cancer cell lines. In silico studies demonstrated a possible multitarget mode of action for the synthesized compounds. The most likely mechanism of action for the new compounds is connected with the activities of Caspase 3 and Caspase 8 and activation of BAX proteins. 相似文献
15.
Dmytro Neshchadin Dr. Rebecca Levinn Georg Gescheidt Prof. Dr. Stephen N. Batchelor Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(23):7008-7016
Polyphenols occur naturally in a vast variety of plants. One of their predominant properties is their antioxidant activity. To provide a deeper understanding of the antioxidant mechanism, 1H CIDNP spectroscopy (CIDNP=chemically induced dynamic nuclear polarization) is used to study model hydrogen abstraction reactions with four catechin‐based polyphenols: catechin (CA), gallocatechin (GC), epigallocatechin (EGC), and epigallocatechin gallate (EGCG). The experiments involve photoinduced hydrogen‐atom transfer to a hydrogen abstractor (e.g., excited isopropylthioxanthone) followed under steady‐state conditions and in a time‐resolved fashion (resolution 500 ns–1 ms). It is found that hydrogen abstraction is an essentially stochastic process with a slight preference for the B rings in the catechin‐based polyphenols. Remarkably, analogous reactivity patterns could be followed in the “real systems”, green tea and red wine. We also show that CIDNP can be used as a semiquantitative tool to assess chemical reactivity. 相似文献
16.
Optical properties of near-stoichiometric compositions of Ba3B′B″2O9 (B′=Mg, Co or Zn and B″=Nb or Ta) perovskite type materials were studied by means of photoluminescence (PL) spectroscopy. Ba3B′B″2O9 perovskites belong to the family of perovskite materials that exhibit phase transition from a completely disordered system having space group Pm-3m to a 1:2 ordered one with space group P-3m1. As revealed by X-ray diffraction, deviation from stoichiometry results in the formation of Ba- and Nb-rich phases. Photoluminescence measurements demonstrated the presence of two broad peaks, the position of which depends on secondary phase formation: the first one, attributed to the disordered Pm-3m phase, is positioned at approximately 430 nm and the second band, positioned at lower energies (i.e., longer wavelengths, around 900 nm), was ascribed to the formation of the 1:2 ordered P-3m1 phase. The position of the first peak is influenced by the bond network through distortions in the local environment caused by the specific electronic structure of the B′ cation. 相似文献
17.
A direct computational approach for lifetime prediction of fibre-reinforced polymer (FRP) composites is presented. The approach is based on a direct method which allows predicting the fatigue life from the stabilised damage state. The classical direct method is generalised to the case of coupled plasticity with damage mechanics of the UD-FRP composite materials [1]. The constitutive model is based on a continuous damage meso-scale approach [2]. By analysing damage variables and thermodynamical forces associated with damage at the stabilised state, fatigue life prediction law is proposed as a power law function of stabilised thermodynamic forces. The obtained numerical results have been validated by experimental test results on standard glass-fibre/epoxy angle-ply and cross-ply laminate plates. The proposed approach could serve as a useful tool for the design of FRP composites. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
18.
Dmytro V. Baidiuk 《Journal of Mathematical Sciences》2013,194(5):513-531
The notions of the boundary triplet of an isometric operator V in the Pontryagin space and the corresponding function Weyl are introduced. Proper extensions of the isometric operator V, their spectra, and canonical and generalized resolvents of the operator V are described. 相似文献
19.
Benjamin Mills Dmytro Kundys Maria Farsari Sakellaris Mailis Robert W. Eason 《Applied Physics A: Materials Science & Processing》2012,108(3):651-655
Single ultra-short pulses from Gaussian and vortex beams have been used for the fabrication of complex micro-structures via multi-photon polymerization. The complexity of the resultant micro-structures stems from the modification of both transverse intensity and phase profiles of these single pulses to create modulated scaffolds and hollow cylinders. Experimental results are compared to theoretical models, and good agreement is shown. 相似文献
20.
Here we describe a non-traditional method to identify cancerous human cervical epithelial cells in a culture dish based on physical adhesion between silica beads and cells. It is a simple optical fluorescence-based technique which detects the relative difference in the amount of fluorescent silica beads physically adherent to surfaces of cancerous and normal cervical cells. The method utilizes the centripetal force gradient that occurs in a rotating culture dish. Due to the variation in the balance between adhesion and centripetal forces, cancerous and normal cells demonstrate clearly distinctive distributions of the fluorescent particles adherent to the cell surface over the culture dish. The method demonstrates higher adhesion of silica particles to normal cells compared to cancerous cells. The difference in adhesion was initially observed by atomic force microscopy (AFM). The AFM data were used to design the parameters of the rotational dish experiment. The optical method that we describe is much faster and technically simpler than AFM. This work provides proof of the concept that physical interactions can be used to accurately discriminate normal and cancer cells. 相似文献