全文获取类型
收费全文 | 265篇 |
免费 | 39篇 |
国内免费 | 4篇 |
专业分类
化学 | 105篇 |
晶体学 | 2篇 |
力学 | 2篇 |
综合类 | 1篇 |
数学 | 46篇 |
物理学 | 152篇 |
出版年
2022年 | 8篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 7篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 8篇 |
2011年 | 18篇 |
2010年 | 5篇 |
2009年 | 12篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 3篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1967年 | 2篇 |
1965年 | 3篇 |
1963年 | 4篇 |
1962年 | 2篇 |
1958年 | 3篇 |
排序方式: 共有308条查询结果,搜索用时 15 毫秒
1.
Tomáš Hložek Martin Štícha Miroslava Bursová Ivan Jelínek Petr Tůma Radomír Čabala 《Electrophoresis》2020,41(18-19):1564-1567
Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10–1000 ng/mL), with adequate accuracy (90.1–114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR. 相似文献
2.
3.
4.
分别用连续波1.319μm激光和10.6μm激光辐照PC型HgCdTe红外探测器时,得到了不同辐照光功率密度下,探测器输出的一系列实验结果。给出了在波长为1.319μm的波段内激光辐照下PC型HgCdTe探测器的饱和阈值;用波长为10.6μm的波段外CO2激光辐照探测器时,发现了一些与波段内激光辐照探测器时大不相同的实验现象;对实验结果进行了分析。简要总结了PC型HgCdTe探测器对于波段内和波段外激光辐照的响应机制。 相似文献
5.
In the framework of path integrals we present a solution to the Schrödinger equation for a free particle confined to the half-linex > 0. A solution in question corresponds to the boundary condition (/x) (0,t)= (0,t) where is a real constant. 相似文献
6.
A number of α-β acetylenic carbinols RFCCC(OH)RR′, in which the acetylenic proton was substituted by a F-alkyl group, were first prepared, from a classical reaction of (F-alkynyl)- lithium derivatives RFCCLi upon various carbonyl compounds.On another hand, the reaction of propargyl bromide metallic complexes (organoaluminic, or ultrasonic irradiation activated organozinc) upon some polyfluorinated ketones RFCOR led to the formation, in convenient yields, of the propargylic carbinols HCCCH2C(OH)RRF.The synthesis and properties of these series of new (F-alkyl) substituted acetylenic and propargylic alcohols are described and discussed. 相似文献
7.
Magnetics structures of powdered orthorhombic R(Cu, Ni)2 compounds (R = heavy rare earth) determined by neutron diffraction are described. The influence of magnetocrystalline anisotropy and exchange interactions on the type of magnetic ordering is discussed.Dedicated to Academician Vladimír Hajko on the occasion of his 65th brithday.We would like to express our thanks to Professor P. Luká for continual interest and encouragement and to . Zajac and V. Sechovský for many fruitfull discussions. 相似文献
8.
Naïma Khiri 《Tetrahedron letters》2005,46(35):5807-5810
Enantiomerically pure (E)-β-sulfinylenones are smoothly prepared from β-ketoesters in three steps with good overall yield. Since they can be the substrates of many diastereoselective reactions, they represent versatile precursors of a wide range of chiral building blocks. We propose a rationale to explain the formation of (E)-β-sulfinylenones from the corresponding δ-enol-methylethers. 相似文献
9.
D. Vogtenhuber-Pawelczak P. Herzig J. Klíma 《Zeitschrift für Physik B Condensed Matter》1991,84(2):211-219
Titanium aluminium nitrides, Ti1-x
Al
x
N, can be prepared as films by various sputtering methods. They form metastable phases in which the titanium and aluminium atoms are randomlydistributed over the metal sublattice. In the present work two ordered model structures, Ti3AlN4 and TiAlN2, have been chosen, for which LAPW band-structure calculations have been performed. The calculated densities of states (DOS) and the local partial DOS for both model structures are compared with the corresponding values for TiN. Characteristic changes in the DOS of the p band are observed which are caused by the nitrogenp orbitals that point towards the aluminium spheres. The bonding situation is investigated on the basis of electron density and difference electron density plots. The substitution of titanium atoms by aluminium atoms leads to stronger covalent Ti–Ti and N–Ti bonds and to additional ionic bonding contributions by the aluminium atoms whose ionicity increases from Ti0.50Al0.50N to Ti0.75Al0.25N. 相似文献
10.
Karolina Kucharska Marta Pilz Krzysztof Bielec Tomasz Kalwarczyk Patrycja Ku
ma Robert Hoyst 《Molecules (Basel, Switzerland)》2021,26(12)
The oxazole yellow dye, YOYO-1 (a symmetric homodimer), is a commonly used molecule for staining DNA. We applied the brightness analysis to study the intercalation of YOYO-1 into the DNA. We distinguished two binding modes of the dye to dsDNA: mono-intercalation and bis-intercalation. Bis-intercalation consists of two consecutive mono-intercalation steps, characterised by two distinct equilibrium constants (with the average number of base pair per binding site equals 3.5): and , respectively. Mono-intercalation dominates at high concentrations of YOYO-1. Bis-intercalation occurs at low concentrations. 相似文献