全文获取类型
收费全文 | 1629篇 |
免费 | 57篇 |
国内免费 | 4篇 |
专业分类
化学 | 1202篇 |
晶体学 | 8篇 |
力学 | 38篇 |
数学 | 159篇 |
物理学 | 283篇 |
出版年
2023年 | 19篇 |
2022年 | 14篇 |
2021年 | 46篇 |
2020年 | 44篇 |
2019年 | 36篇 |
2018年 | 24篇 |
2017年 | 24篇 |
2016年 | 68篇 |
2015年 | 56篇 |
2014年 | 60篇 |
2013年 | 82篇 |
2012年 | 93篇 |
2011年 | 106篇 |
2010年 | 81篇 |
2009年 | 84篇 |
2008年 | 92篇 |
2007年 | 89篇 |
2006年 | 70篇 |
2005年 | 60篇 |
2004年 | 52篇 |
2003年 | 32篇 |
2002年 | 40篇 |
2001年 | 20篇 |
2000年 | 16篇 |
1999年 | 17篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 11篇 |
1993年 | 9篇 |
1991年 | 7篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1984年 | 14篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1976年 | 7篇 |
1972年 | 5篇 |
1971年 | 6篇 |
1961年 | 8篇 |
1960年 | 70篇 |
1943年 | 4篇 |
1939年 | 5篇 |
1935年 | 4篇 |
排序方式: 共有1690条查询结果,搜索用时 15 毫秒
1.
Biodistribution study of free and microencapsulated 6‐methylcoumarin in Wistar rats by HPLC
下载免费PDF全文
![点击此处可从《Biomedical chromatography : BMC》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Aura Rocío Hernández Luis Fernando Ospina Diana Marcela Aragón 《Biomedical chromatography : BMC》2015,29(2):176-181
A sensitive, specific and reproducible HPLC method has been developed and validated for the quantitative determination of 6‐methylcoumarin (6MC) in plasma and other tissues in Wistar rats. A C18 column was used with UV detection at 321 nm and a gradient system consisting of methanol‐deionized water was used as mobile phase. The retention time for 6MC was 14.921 min and no interfering peaks were observed for any of the matrices. Linear relationships (r2 > 0.997) were obtained between the peak height ratios and the corresponding biological sample concentrations over the range 0.4–12.8 µg/mL. Precision and accuracy were evaluated; the coefficient of variation and the relative error for all of the organs were <2 and 7%, respectively. The limit of quantitation was 0.20 µg/mL for the heart and 0.30 µg/mL for the other tissues evaluated. This HPLC method was successfully used in the determination of 6MC in the biodistribution study after administration of 200 mg/kg of both 6MC‐free and 6MC‐loaded polymeric microparticles. In this study, extensive 6MC was found, in both free and microencapsulated forms, in all the organs tested. The 6MC‐free showed a range of between 1.7 and 11.5 µg/g, while the microencapsulated 6MC showed concentrations of between 6.35 and 17.7 µg/g, suggesting that 6MC improved absorption rate. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
2.
de Santana Felipe Silva Gracioso Louise Hase Karolski Bruno dos Passos Galluzzi Baltazar Marcela Mendes Maria Anita do Nascimento Claudio Augusto Oller Perpetuo Elen Aquino 《Applied biochemistry and biotechnology》2019,189(1):103-115
Applied Biochemistry and Biotechnology - The human exposure to bisphenol A (BPA) occurs frequently. Once, this compound was one of the highest volume chemicals produced worldwide and used as a... 相似文献
3.
Flückiger 《Analytical and bioanalytical chemistry》1873,12(1):315-315
4.
5.
Flávio A. Pavan Yoshitaka Gushikem Celso C. Moro Tania M. Costa Edilson V. Benvenutti 《Colloid and polymer science》2003,281(2):173-177
Anilinepropylsilica xerogel was obtained by using an appropriate organosilane and tetraethyl orthosilicate as precursor reagents. The gelation was carried out using HF and NaF as catalysts. The presence of Na+ (when NaF was used) resulted in a decrease in the final organic content of the materials. This effect was interpreted as an inhibition of the organosilane polycondensation possibly due to the Na+ interaction with the SiO- groups of the hydrolyzed organosilane. The presence of Na+ also results in morphological changes in the xerogels. 相似文献
6.
Iron oxide nanoparticles made from the thermal decomposition method are highly uniform in all respects (size, shape, composition and crystallography), making them ideal candidates for many bioapplications. The surfactant coating on the as-synthesized nanoparticles renders the nanoparticles insoluble in aqueous solutions. For biological applications nanoparticles must be water soluble. Here we demonstrate the phase transfer of our nanoparticles with the biocompatible copolymer Pluronic F127. Transmission electron microscopy, Fourier transform infrared spectroscopy and dynamic light scattering indicate that the nanoparticles are coated discretely. Magnetic measurements show that the nanoparticles remain superparamagnetic with saturation magnetization ∼96% of the maximum theoretical value. 相似文献
7.
E. Liénard G. Ban J. Blieck D. Durand F. Duval X. Fléchard M. Herbane M. Labalme Y. Lemière F. Mauger A. Méry O. Naviliat-Cuncic D. Rodríguez J. C. Thomas 《Hyperfine Interactions》2006,172(1-3):29-33
We report on the status of the LPCTrap experiment, devoted to measure the β–ν angular correlation in the pure Gamow–Teller
decay of 6He. This measurement is motivated by the search for the presence of tensor type contributions to the weak interaction. The
6He ions are confined in a novel transparent Paul trap. The β particles and the recoil ions are detected in coincidence to
deduce the angular correlation parameter. The commissioning run performed in 2005 has given the proof of principle of this
experiment. Up to 105 coincidences were recorded during a second run in 2006. 相似文献
8.
Marcela Szopos 《Comptes Rendus Mathematique》2004,338(6):447-452
It is known from differential geometry that one can reconstruct a curve with n?1 prescribed curvature functions, if these functions can be differentiated a certain number of times in the usual sense and if the first n?2 functions are strictly positive. We establish here that this result still holds under the assumption that the curvature functions belong to some Sobolev spaces, by using the notion of derivative in the distributional sense. We also show that the mapping that associates with such prescribed curvature functions the reconstructed curve is of class . To cite this article: M. Szopos, C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
9.
10.
Experiments in dc supplied corona discharge in natural gas + air mixture and in combustion exhaust of natural gas + air mixture were realized. The influence of discharge on CO, CO2, NO
x
and other minority components was studied using IR absorption spectrometry. Production of NCO radicals in gas and consequent formation of NCO containing surface layers on a plate electrode was detected. In natural gas + air mixture after about 1 min oxygen poor combustion exhaust was produced due to slow combustion by corona discharge. Occurrence of various pulses in discharge current was typical. 相似文献