全文获取类型
收费全文 | 240篇 |
免费 | 6篇 |
国内免费 | 3篇 |
专业分类
化学 | 172篇 |
晶体学 | 1篇 |
力学 | 1篇 |
数学 | 30篇 |
物理学 | 45篇 |
出版年
2019年 | 6篇 |
2018年 | 3篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 3篇 |
2013年 | 12篇 |
2012年 | 11篇 |
2011年 | 17篇 |
2010年 | 14篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 13篇 |
2006年 | 10篇 |
2005年 | 16篇 |
2004年 | 12篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 7篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1969年 | 1篇 |
1909年 | 2篇 |
1899年 | 1篇 |
1895年 | 1篇 |
1881年 | 1篇 |
1876年 | 2篇 |
1868年 | 3篇 |
1863年 | 2篇 |
排序方式: 共有249条查询结果,搜索用时 15 毫秒
81.
E. I. Voit A. V. Voit A. V. Gerasimenko V. I. Sergienko 《Journal of Structural Chemistry》2000,41(2):206-211
A correlation is established between the mean energy of fluorine addition in a particular coordination polyhedron and the
fluorine content in fluorozirconates by quantum chemical model cluster calculations and analysis of structural data for crystalline
fluorozirconates. A new energy approach to studies of complex fluorides is suggested. It is shown that the mean energy of
fluorine addition varies within a narrow range for any structural unit met in real fluorozirconate crystals. Based on the
energy approach to analysis of vibrational spectra it is found that the coordination number of zirconium in a series of barium
fluorozirconate glasses is 7 or 8.
Translated fromZhurnal Strukturmoi Khimii, Vol. 41, No. 2, pp. 255–262. March–April, 2000. 相似文献
82.
Prof. Xiaoling Liu Xueyi Wang Prof. Brigitte Voit Dr. Dietmar Appelhans 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(60):13694-13700
Stimulus-responsive polymeric nanocapsules usable as cell mimics can be engineered to precisely control cargo release. This work reports the release behavior of post-loaded nanoparticles through permeable membranes of stable pH and temperature dual-responsive polymeric nanocapsules (CP1, CP2, and CP3) with the same membrane thickness but different membrane composition, prepared by layer-by-layer assembly and surface-initiated single electron transfer living radical polymerization, respectively. These nanocapsules differ in their tunable membrane permeability for post-loaded nanoparticles as protein mimics, tailored by pH and temperature stimuli. Release mechanisms are dominated by membrane composition, such as polyelectrolyte multilayer membrane for CP1, pure cationic membrane for CP2, and valve-like functions for CP3. Thus, one can postulate the main locations of post-loaded protein mimics in the different nanocapsules. Understanding the post-loading and diffusion mechanism of nanoparticles through permeable membranes in cell mimics paves the way for the construction of new “smart” synthetic protocells with control over the exchange of bioactive nanoparticles between different compartments. 相似文献
83.
84.
Jan Stadermann Maria Riedel Hartmut Komber Frank Simon Brigitte Voit 《Journal of polymer science. Part A, Polymer chemistry》2012,50(7):1351-1361
Two phase separating block copolymers equipped with functional groups (acid and alkyne) were synthesized via reversible addition‐fragmentation chain transfer (RAFT) polymerization. Thin films of these materials were prepared and examined with regard to surface morphology, surface composition, and film stability. Self‐assembled structures with domain sizes of about 40 nm were detected through atomik force microscopy (AFM) analysis while X‐ray photoelectron spectroscopy measurements revealed a balanced surface exposure of the two segregated phases. Thus, reactive groups being present in both phases are specifically provided within nanoscopic surface areas. The films showed good stability on exposure to various solvents but the self‐organized surface patterns were only resistant toward ethanol. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
85.
Senkovskyy V Tkachov R Komber H Sommer M Heuken M Voit B Huck WT Kataev V Petr A Kiriy A 《Journal of the American Chemical Society》2011,133(49):19966-19970
Strongly electron-deficient (n-type) main-chain π-conjugated polymers are commonly prepared via well-established step-growth polycondensation protocols which enable limited control over polymerization. Here we demonstrate that activated Zn and electron-deficient brominated thiophene-naphthalene diimide oligomers form anion-radical complexes instead of conventional Zn-organic derivatives. These highly unusual zinc complexes undergo Ni-catalyzed chain-growth polymerization leading to n-type conjugated polymers with controlled molecular weight, relatively narrow polydispersities, and specific end-functions. 相似文献
86.
Palladium‐Catalyzed Chain‐Growth Polycondensation of AB‐type Monomers: High Catalyst Turnover and Polymerization Rates 下载免费PDF全文
Dr. Roman Tkachov Dr. Volodymyr Senkovskyy Dr. Tetyana Beryozkina Dr. Kseniya Boyko Prof. Dr. Vasiliy Bakulev Dr. Albena Lederer Dr. Karin Sahre Prof. Dr. Brigitte Voit Dr. Anton Kiriy 《Angewandte Chemie (International ed. in English)》2014,53(9):2402-2407
Chain‐growth catalyst‐transfer polycondensations of AB‐type monomers is a new and rapidly developing tool for the preparation of well‐defined π‐conjugated (semiconducting) polymers for various optoelectronic applications. Herein, we report the Pd/PtBu3‐catalyzed Negishi chain‐growth polycondensation of AB‐type monomers, which proceeds with unprecedented TONs of above 100 000 and TOFs of up to 280 s?1. In contrast, related AA/BB‐type step‐growth polycondensation proceeds with two orders of magnitude lower TONs and TOFs. A similar trend was observed in Suzuki‐type polycondensation. The key impact of the intramolecular (vs. intermolecular) catalyst‐transfer process on both polymerization kinetics and catalyst lifetime has been revealed. 相似文献
87.
Mona Abd Elrehim Brigitte Voit Bernd Bruchmann Klaus‐Jochen Eichhorn Karina Grundke C. Bellmann 《Journal of polymer science. Part A, Polymer chemistry》2005,43(15):3376-3393
The hydroxy end groups of aromatic and aliphatic hyperbranched poly‐(urea urethane)s prepared with an AA* + B*B2 one‐pot method were modified with phenylisocyanate, butylisocyanate, and stearylisocyanate. The success of the modification reaction was verified with 1H NMR and IR spectroscopy. Linear model poly‐(urea urethane)s were prepared, too, for comparison. The bulk properties of OH functionalized hyperbranched poly(urea urethane)s, compared with those of linear analogues and modified hyperbranched poly(urea urethane)s, were studied with differential scanning calorimetry, thermogravimetric analysis, and temperature‐dependent Fourier transform infrared measurements. Transparent and smooth thin films could be prepared from all polymer samples and were examined with a light microscope, a microglider, and an atomic force microscope. The properties of the polymer surface were examined by measurements of the contact angle and zeta potential. For all samples, the properties were mainly governed by the strong interactions of the urea and urethane units within the backbone, whereas the influence of the nature of the end groups and of the branched structure was reduced in comparison with other hyperbranched polymer systems. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3376–3393, 2005 相似文献
88.
The Jπ value of the 12C + 12C resonance at Ec.m. = 6.25 MeV has been determined to be 2+. This is in contrast to several theoretical predictions which give Jπ = 0+. In addition, Jπ values of several sub-Coulomb resonances of the 12C + 12C reaction have been determined for the first time. 相似文献
89.
The elastic scattering of 12C on 11B has been analyzed in the framework of the molecular wave function method. It turns out that a coherent sum of the direct and transfer amplitudes gives better agreement with the experimental data than an incoherent sum. Non-adiabatic and Coriolis coupling terms seem to be of little importance in this particular case. 相似文献
90.
Klajnert B Appelhans D Komber H Morgner N Schwarz S Richter S Brutschy B Ionov M Tonkikh AK Bryszewska M Voit B 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(23):7030-7041
Maltose-modified poly(propylene imine) (PPI) dendrimers were synthesized by reductive amination of unmodified second- to fifth-generation PPI dendrimers in the presence of excess maltose. The dendrimers were characterized by using (1)H NMR, (13)C NMR, and IR spectroscopies; laser-induced liquid beam ionization/desorption mass spectrometry; dynamic light scattering analyses; and polyelectrolyte titration. Their scaffolds have enhanced molecular rigidity and their outer spheres, at which two maltose units are bonded to the former primary amino groups on the surface, have hydrogen-bond-forming properties. Furthermore, the structural features reveal the presence of a dense shell. Experiments involving encapsulation (1-anilinonaphthalene-8-sulfonic acid) and biological properties (hemolysis and interactions with human serum albumin (HSA) and prion peptide 185-208) were performed to compare the modified with the unmodified dendrimers. These experiments gave the following results: 1) The modified dendrimers entrapped a low-molecular-weight fluorescent dye by means of a dendritic box effect, in contrast to the interfacial uptake characteristic of the unmodified PPI dendrimers. 2) Both low- and high-generation dendrimers containing maltose units showed markedly reduced toxicity. 3) The desirable features of bio-interactions depended on the generation of the dendrimer; they were retained after maltose substitution, but were now mainly governed by nonspecific hydrogen-bonding interactions involving the maltose units. The modified dendrimers interacted with HSA as strongly as the parent compounds and appeared to have potential use as antiprion agents. These improvements will initiate the development of the next platform of glycodendrimers in which apparently contrary properties can be combined, and this will enable, for example, therapeutic products such as more efficient and less toxic antiamyloid agents to be synthesized. 相似文献