全文获取类型
收费全文 | 205篇 |
免费 | 14篇 |
国内免费 | 2篇 |
专业分类
化学 | 119篇 |
力学 | 2篇 |
数学 | 78篇 |
物理学 | 22篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 22篇 |
2020年 | 10篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 19篇 |
2012年 | 16篇 |
2011年 | 19篇 |
2010年 | 24篇 |
2009年 | 9篇 |
2008年 | 6篇 |
2007年 | 8篇 |
2005年 | 1篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1986年 | 2篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 4篇 |
排序方式: 共有221条查询结果,搜索用时 62 毫秒
41.
We study nonlinear wave and heat equations on ℝ
d
driven by a spatially homogeneous Wiener process. For the wave equation we consider the cases of d = 1, 2, 3. The heat equation is considered on an arbitrary ℝ
d
-space. We give necessary and sufficient conditions for the existence of a function-valued solution in terms of the covariance
kernel of the noise.
Received: 1 April 1998 / Revised version: 23 June 1999 / Published online: 7 February 2000 相似文献
42.
Szymon Poliski Sylwia Kowalska Patrycja Topka Aleksandra Szydowska-Czerniak 《Molecules (Basel, Switzerland)》2021,26(18)
In this study, dark chocolates (DCh) containing zinc lactate (ZnL) were enriched with extracts from elderberries (EFrE), elderflowers (EFlE), and chokeberries (ChFrE) to improve their functional properties. Both dried plant extracts and chocolates were analyzed for antioxidant capacity (AC) using four different analytical methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), cupric ion-reducing antioxidant capacity (CUPRAC), and ferric-reducing antioxidant power (FRAP), while total phenolic content (TPC) was determined by Folin–Ciocalteu (F–C) assay. An increase in antioxidant properties of fortified chocolates was found, and the bioaccessibility of their antioxidants was evaluated. The highest AC and TPC were found in ChFrE and chocolate with chokeberries (DCh + ChFrE) before and after simulated in vitro digestion. Bioaccessibility studies indicated that during the simulated digestion the AC of all chocolates reduced significantly, whereas insignificant differences in TPC results were observed between chemical and physiological extracts. Moreover, the influence of plant extracts on physicochemical parameters such as moisture content (MC), fat content (FC), and viscosity of chocolates was estimated. Furthermore, scanning electron microscopy with dispersive energy spectroscopy (SEM-EDS) was used to analyze surface properties and differences in the chemical composition of chocolates without and with additives. 相似文献
43.
Szymon Dziomba Magdalena Wysocka Joanna Jońca Laura Sola Aleksandra Steć Krzysztof Waleron Bartosz Wielgomas 《Electrophoresis》2021,42(20):2010-2017
The capillary zone electrophoresis (CZE) has recently been proposed by our group as a novel technique for outer membrane vesicles (OMVs) characterization (J. Chromatography 1621 (2020) 461047). In present work the impact of selected parameters of CZE method on OMVs isolates analysis was assessed. It was shown that the extension of sample injection plug length significantly improves the detectability of macromolecular aggregates in CZE. Moreover, a negligible adsorption of OMVs to both uncoated and polymer-modified (poly(DMA-GMA-MAPS)) capillary walls was proven. Finally, the relaxation effect as well as deformation/polarization of vesicles were demonstrated to affect OMVs electrophoretic mobility. The significance of these findings was discussed. 相似文献
44.
Wojtek Michalowski Marta Kersten Szymon Wilk Roman Słowiński 《European Journal of Operational Research》2007
The Mobile Emergency Triage (MET) system is a clinical triage support system that aids physicians in making triage decisions as to whether a child presenting in the Emergency Department of a hospital with a specific pain complaint should be discharged to a family physician, needs to be admitted for further investigation/observation, or requires an urgent specialist consult. The system’s mobile component is designed to work on handheld computers. This paper presents our experience and discusses our original solutions with regard to designing man–machine interactions for mobile clinical support systems. The specific interactions adopted in the MET design that are discussed in the paper were created in consultation with potential end-users and tested at the Children’s Hospital of Eastern Ontario in Ottawa. 相似文献
45.
It is shown that two real functionsf andg, defined on a real intervalI, satisfy the inequalitiesf(x + (1 – )y) g(x) + (1 – )g(y) andg(x + (1 – )y) f(x) + (1 – )f(y) for allx, y I and [0, 1], iff there exists an affine functionh: I such thatf h g. As a consequence we obtain a stability result of Hyers—Ulam type for affine functions. 相似文献
46.
Dr. Szymon Sobczak Kinga Roszak Prof. Andrzej Katrusiak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(45):e202201235
The pressure-induced transformation of plane-square complex nickel(II) bis(N,N-diethyldithiocarbamate) between its soft dithiocarbamate (form I) and thioureide (form II) mesomeres is coupled to the interchange of anagostic Ni⋅⋅⋅H−C interactions from methylene to the methyl group, respectively. At 1.23 GPa, the clearly visible giant anomalous compressibility of the crystal reveals a potential-energy difference of 5.4 kJ mol−1 between the two complex forms. The structural and spectroscopic results, which are supported by quantum-mechanical calculations, connect this solid-state phase transition with the mesomeric transition, and this is accompanied by the conformational transformation of anagostic Ni⋅⋅⋅H−C rearrangement and formation of the charge-assisted S−⋅⋅⋅H−C bond under pressure. 相似文献
47.
Szymon Pliś 《Mathematische Zeitschrift》2014,276(3-4):969-983
We study the Dirichlet problem for the Monge–Ampère equation on almost complex manifolds. We obtain the existence of the unique smooth solution in strictly pseudoconvex domains. 相似文献
48.
Synthesis and properties are described of multilayered stationary phases containing quaternary amine functional groups used for the analysis of inorganic anions by ion chromatography. The bonded phases were characterized by elemental analysis, solid state (13)C NMR spectroscopy and chromatographic methods. The surface of polyhydroxyethyl methacrylate (solid support) was coated with polymeric layers formed by condensation polymerization of primary amine with diepoxide. Each layer of the anion exchange stationary phase consisted of methylamine and 1,4-butanedioldiglycidyl ether copolymer. A series of stationary phases with different number of polymerized layers were tested. Separation of inorganic anions, such as F(-), Cl(-), NO(2) (-), Br(-), NO(3) (-), were performed. Aqueous hydroxide, carbonate and bicarbonate solutions were used as mobile phases. 相似文献
49.
Szymon Godlewski Grzegorz Goryl Jacek J. Kolodziej Marek Szymonski 《Applied Surface Science》2010,256(12):3746-3752
In this report we present results of combined high resolution LT-STM and LEED studies of ultrathin epitaxial KBr films grown on an InSb(0 0 1) c(8 × 2) substrate. Based on atomically resolved STM maps and LEED diffractograms the film structure as well as superimposed electronic effects are explained. The origin of additional 4 × 4 superstructure observed on ultrathin films is discussed. Possible application of the KBr/InSb system as a template for growing organic molecule structures is suggested. 相似文献
50.
Szymon Godlewski Antoni Tekiel Janusz Budzioch Dr. Andre Gourdon Dr. Jakub S. Prauzner‐Bechcicki Dr. Marek Szymonski Prof. 《Chemphyschem》2009,10(18):3278-3284
Behavior of large organic molecules equipped with spacer groups (Violet Landers, VL) on the TiO2(110)‐(1×1) surfaces is investigated by means of high‐resolution scanning tunneling microscopy (STM). Two distinct adsorption geometries are observed. We demonstrate that the molecule adsorption morphology can be alternated by well‐controlled STM tip‐induced manipulation. It is used to probe the mobility of molecules and reveals locking in one of the analyzed adsorption sites, thus allow to enhance or reduce the mobility along the [001] direction. Field induced hydrogen desorption is used to perform lateral STM manipulation on a hydroxyl‐free surface, which provides insight into the influence of surface hydroxyl groups on the molecule behavior. The ability to image with submolecular resolution both the central board and the spacer groups of the VL molecule is demonstrated. 相似文献