全文获取类型
收费全文 | 526篇 |
免费 | 32篇 |
国内免费 | 1篇 |
专业分类
化学 | 488篇 |
晶体学 | 1篇 |
力学 | 7篇 |
数学 | 34篇 |
物理学 | 29篇 |
出版年
2023年 | 8篇 |
2022年 | 30篇 |
2021年 | 27篇 |
2020年 | 15篇 |
2019年 | 23篇 |
2018年 | 7篇 |
2017年 | 15篇 |
2016年 | 28篇 |
2015年 | 22篇 |
2014年 | 26篇 |
2013年 | 35篇 |
2012年 | 46篇 |
2011年 | 37篇 |
2010年 | 37篇 |
2009年 | 18篇 |
2008年 | 34篇 |
2007年 | 31篇 |
2006年 | 29篇 |
2005年 | 27篇 |
2004年 | 9篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1978年 | 3篇 |
1962年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有559条查询结果,搜索用时 31 毫秒
51.
Pavel Jandera Jiří Urban Veronika Škeříková Pavel Langmaier Romana Kubíčková Josef Planeta 《Journal of chromatography. A》2010,1217(1):22-33
We prepared hybrid particle-monolithic polymethacrylate columns for micro-HPLC by in situ polymerization in fused silica capillaries pre-packed with 3–5 μm C18 and aminopropyl silica bonded particles, using polymerization mixtures based on laurylmethacrylate–ethylene dimethacrylate (co)polymers for the reversed-phase (RP) mode and [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl) zwitterionic (co)polymers for the hydrophilic interaction (HILIC) mode. The hybrid particle-monolithic columns showed reduced porosity and hold-up volumes, approximately 2–2.5 times lower in comparison to the pure monolithic columns prepared in the whole volume of empty capillaries. The elution volumes of sample compounds are also generally lower in comparison to packed or pure monolithic columns. The efficiency and permeability of the hybrid columns are intermediate in between the properties of the reference pure monolithic and particle-packed columns. The chemistries of the embedded solid particles and of the interparticle monolithic moiety in the hybrid capillary columns contribute to the retention to various degrees, affecting the selectivity of separation. Some hybrid columns provided improved separations of proteins in comparison to the reference particle-packed columns in the reversed-phase mode. Zwitterionic hybrid particle-monolithic columns show dual mode retention HILIC/RP behaviour depending on the composition of the mobile phase and allow separations of polar compounds such as phenolic acids in the HILIC mode at lower concentrations of acetonitrile and, often in shorter analysis time in comparison to particle-packed and full-volume monolithic columns. 相似文献
52.
Simone Göttlich Simon Hoher Patrick Schindler Veronika Schleper Alexander Verl 《Applied Mathematical Modelling》2014
In this paper a model comparison approach based on material flow systems is investigated that is divided into a microscopic and a macroscopic model scale. On the microscopic model scale particles are simulated using a model based on Newton dynamics borrowed from the engineering literature. Phenomenological observations lead to a hyperbolic partial differential equation on the macroscopic model scale. Suitable numerical algorithms are presented and both models are compared numerically and validated against real-data test settings. 相似文献
53.
Boris Remenec Silvia Dulanská Veronika Gardoňová Ľubomír Mátel 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):907-910
This paper describes a rapid method of 94Nb pre-concentration, separation and purification by using cation and anion exchange resins. The method is suitable for analyzing highly contaminated radioactive waste samples in a relatively short time and high decontamination factors. The use and effectiveness of the method was successfully tested by analysis of samples from nuclear reactor parts such as control rod drive shaft, shielding cassettes, neutron in-core measurement channels (KNI), pressure vessel construction material and fuel cassette construction material samples. 相似文献
54.
Edit Csapó Péter Buglyó Nóra Veronika Nagy M. Amélia Santos Alma Corona Etelka Farkas 《Polyhedron》2010
Two histidinehydroxamic acid derivatives (N-methyl-histidinehydroxamic acid, N-Me-Hisha and Z-histidinehydroxamic acid, Z-Hisha) have been synthesized and their complexation with Cu2+-, Ni2+- and Zn2+-ions has been studied by using pH-potentiometric, UV–Vis, CD, 1H NMR, EPR and ESI-MS methods. Both of the two new derivatives contain one donor atom less compared to the histidinehydroxamic acid (Hisha). In the case of N-Me-Hisha the hydroxamate-N as donor is eliminated, while the coordination of the amino-N of Z-Hisha is not possible at all. 相似文献
55.
Veronika Nagy Erika Turcsi Péter Molnár Zoltán Szabó József Deli 《Tetrahedron letters》2007,48(51):9012-9014
Latoxanthin was isolated as a minor carotenoid from the ripe fruits of yellow tomato shaped paprika (Capsicum annuum var. lycopersiciforme flavum) and identified as (all-E,3S,5R,6R,3′S,5′R,6′S)-5′,6′-epoxy-5,6,5′,6′-tetrahydro-β,β-carotene-3,5,6,3′-tetrol based on spectral data. 相似文献
56.
Veronika Sobotíková Miloslav Feistauer 《Numerical Methods for Partial Differential Equations》2007,23(6):1368-1395
This paper is concerned with the effect of numerical integration applied to the discontinuous Galerkin finite element discretization of nonlinear convection‐diffusion problems in 2D. In the space semidiscretization the volume and line integrals are evaluated by numerical quadratures. Our goal is to estimate the error caused by the numerical integration and to show what numerical quadratures guarantee that the accuracy of the method with exact integration is preserved. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007 相似文献
57.
58.
Next‐Generation o‐Nitrobenzyl Photolabile Groups for Light‐Directed Chemistry and Microarray Synthesis
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Nicole Kretschy Ann‐Katrin Holik Prof. Veronika Somoza Dr. Klaus‐Peter Stengele Prof. Mark M. Somoza 《Angewandte Chemie (International ed. in English)》2015,54(29):8555-8559
Light as an external trigger is a valuable and easily controllable tool for directing chemical reactions with high spatial and temporal accuracy. Two o‐nitrobenzyl derivatives, benzoyl‐ and thiophenyl‐NPPOC, undergo photo‐deprotection with significantly improved efficiency over that of the commonly used NPPOC group. The two‐ and twelvefold increase in photo‐deprotection efficiency was proven using photolithograph synthesis of microarrays. 相似文献
59.
Impedimetric Detection of DNA Damage with the Sensor Based on Silver Nanoparticles and Neutral Red
下载免费PDF全文
![点击此处可从《Electroanalysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yury Kuzin Anna Porfireva Veronika Stepanova Vladimir Evtugyn Ivan Stoikov Gennady Evtugyn Tibor Hianik 《Electroanalysis》2015,27(12):2800-2808
Novel electrochemical DNA‐sensor based on glassy carbon electrode (GCE) modified with Ag nanoparticles, Neutral red covalently attached to its surface and native DNA adsorbed on modifier coating was developed for the estimation of DNA damage on example of model system based on Fenton reagent. As was shown, the oxidation process resulted in synchronous increase of electron transfer resistance and capacitance measured by electrochemical impedance spectroscopy (EIS). The contribution of each sensor component on the signal was specified and sensitivity estimated against similar surface coatings. The shift of EIS parameters was found to be higher than that of similar biosensors reported. The DNA sensor was tested on the estimation of antioxidant capacity of green tea infusions again the results of coulometric titration with electrogenerated bromine. 相似文献
60.
Annika Höhn Petra Hartmann Veronika Gebhart Johanna Sonntag Tilman Grune Tobias Jung 《Photochemistry and photobiology》2015,91(4):887-894
In this study, the athermal effects of water‐filtered infrared A (wIRA)‐irradiation (780–1400 nm) on human dermal fibroblasts were investigated. For this purpose, cells were exposed to wIRA‐irradiation (178 mW cm?2 for 1 h), while a sophisticated experimental setup prevented warming of the samples exceeding 0.1°C. The investigated parameters were the formation of reactive oxygen species (ROS), mitochondrial membrane potential and superoxide release, protein oxidation, proliferation rate, as well as intracellular Ca2+‐release in single cells, most of them quantified via fluorescence microscopy and fluorimetric techniques. The existence of actual athermal wIRA‐effects is still intensively discussed, since their detection requires a careful experimental setup and both efficient and powerful temperature regulation of the exposed samples. Here, we can definitively show that some of the supposed athermal wIRA‐effects may be rather artifacts, since wIRA did not reveal any impact on the above mentioned parameters—as long as the temperature of the exposed cells was carefully maintained. Though, we were able to identify an athermal DNA‐protective wIRA‐effect, since the induced DNA damage (quantified via 8‐Oxo‐G‐formation) was significantly decreased after a subsequent UVB‐exposure. These results suggest that many of the supposed athermal wIRA‐effects can be induced by pure warming of the samples, independent from any wIRA‐irradiation. 相似文献