全文获取类型
收费全文 | 234篇 |
免费 | 5篇 |
专业分类
化学 | 209篇 |
晶体学 | 2篇 |
数学 | 5篇 |
物理学 | 23篇 |
出版年
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 5篇 |
2011年 | 17篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2008年 | 11篇 |
2007年 | 12篇 |
2006年 | 17篇 |
2005年 | 21篇 |
2004年 | 16篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1976年 | 5篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1968年 | 1篇 |
1963年 | 2篇 |
1961年 | 1篇 |
1960年 | 3篇 |
1959年 | 3篇 |
1906年 | 1篇 |
1903年 | 2篇 |
排序方式: 共有239条查询结果,搜索用时 31 毫秒
81.
82.
Demel J Pleštil J Bezdička P Janda P Klementová M Lang K 《Journal of colloid and interface science》2011,362(2):532-539
Herein, we report our analysis of the surface modification of polystyrene (PS) when treated under ambient conditions with a common biological buffer such as phosphate buffered saline (PBS) or aqueous solutions of the ionic constituents of PBS. Attenuated total reflection Fourier transform infrared spectroscopy was used for the analysis because the resultant spectra are very sensitive to minor changes in the chemical and structural properties of PS films. In addition, ultraviolet-visible spectroscopy was applied to characterize the surface modifications of PS. Treatment with PBS resulted in the most significant chemical and structural surface modifications of the PS films, as compared with each of the solutions of the constituents of PBS, which were tested separately. A multistep mechanism for the wet modification of PS is discussed. We postulate that the observed surface modifications are the result of photo-oxidation/reduction, swelling, and conformational changes and re-arrangement of the polymer chain. The resultant surface modifications could be similar to those produced by commonly used dry processes such as plasma treatments and electron, ion or ultraviolet irradiation. We found that the modifications that occurred in PBS were more stable than those initiated by dry processes. The formation of active groups on the surface of PS can be controlled by adsorption of bovine serum albumin or thermal annealing of PS before PBS treatment. This approach provides a simple and efficient method for the surface modification of PS for biomedical applications. 相似文献
83.
A cross-over inhibitor of the botulinum neurotoxin light chain B: a natural product implicating an exosite mechanism of action 总被引:1,自引:0,他引:1
Salzameda NT Eubanks LM Zakhari JS Tsuchikama K DeNunzio NJ Allen KN Hixon MS Janda KD 《Chemical communications (Cambridge, England)》2011,47(6):1713-1715
Clostridium botulinum produces the most lethal toxins known to man, as such they are high risk terrorist threats, and alarmingly there is no approved therapeutic. We report the first cross-over small molecule inhibitor of these neurotoxins and propose a mechanism by which it may impart its inhibitory activity. 相似文献
84.
In (Rie?anová and Zajac in Rep. Math. Phys. 70(2):283–290, 2012) it was shown that an effect algebra E with an ordering set $\mathcal{M}$ of states can by embedded into a Hilbert space effect algebra $\mathcal{E}(l_{2}(\mathcal{M}))$ . We consider the problem when its effect algebraic MacNeille completion $\hat{E}$ can be also embedded into the same Hilbert space effect algebra $\mathcal {E}(l_{2}(\mathcal{M}))$ . That is when the ordering set $\mathcal{M}$ of states on E can be extended to an ordering set of states on $\hat{E}$ . We give an answer for all Archimedean MV-effect algebras and Archimedean atomic lattice effect algebras. 相似文献
85.
Agnieszka Maruszewska Wojciech wiereo Marta Skrka-Majewicz Irena Baranowska-Bosiacka Agata Wszoek Katarzyna Janda Daria Kulis Patrycja Kapczuk Dariusz Chlubek Izabela Gutowska 《Molecules (Basel, Switzerland)》2021,26(14)
Breast milk has the most suitable composition for the proper development in the first year of a child’s life. However, it is often replaced with artificial milk. The aim of the study was to analyze the composition of essential elements: Na, K, Ca, P, Mg, Fe, Zn, Cu, and Mn as well as toxic elements: Ni, Pb, Sr, Li, and In in 18 formulas available in Poland. The daily supply was also estimated. The study was performed by Inductively Coupled Plasma Optical Emission Spectrometry method. The results showed the presence of all essential elements tested, but the content of P and Mn significantly differed from the concentrations declared. Such discrepancies can have significant impact on the daily dose of the bioelements taken. However, the content of elements was within the reference standards established by the EU Directive with exception of P, the amount of which exceeded the norms 5.23–18.80-times. Daily supply of P in tested milk as well as Fe and Mn provided with first and hypoallergenic formula exceeded the adequate intake. Analysis revealed the contamination with harmful elements—Pb, Sr, Li, and In were detected in almost all products. The study confirms the data concerning some discrepancies in composition and the contamination of food and may provide information on the feeding quality of children and estimation of health risk associated with exposure to toxic elements. 相似文献
86.
S. Abdul Sattar B. Seetharami Reddy V. Koteswara Rao K. Ramnarayana G. J. Naga Raju S. Bhuloka Reddy T. KD. Phanisree P. V. Madhusudhana Rao 《X射线光谱测定》2012,41(2):111-116
A trace elemental analysis was carried out in various parts of 12 anticancer medicinal plants, using the PIXE (particle‐induced X‐ray emission) technique. A 3‐MeV proton beam was used to excite the samples, and spectra were recorded using a Si (Li) detector. Data analysis was done using the GUPIX software. The elements Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br and Sr were identified, and their concentrations estimated. The results of the present study provide justification for the usage of these medicinal plants in the development of anticancer drugs. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
87.
Z.?Machala I.?Jedlovsky L.?Chládeková B.?Pongrác D.?Giertl M.?Janda L.??ikurová P.?Pol?ic 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):195-204
Three types of DC electrical discharges in atmospheric air (streamer corona, transient spark and glow discharge) were tested
for bio-decontamination of bacteria and yeasts in water solution, and spores on surfaces. Static vs. flowing treatment of
contaminated water were compared, in the latter the flowing water either covered the grounded electrode or passed through
the high voltage needle electrode. The bacteria were killed most efficiently in the flowing regime by transient spark. Streamer
corona was efficient when the treated medium flew through the active corona region. The spores on plastic foil and paper surfaces
were successfully inactivated by negative corona. The microbes were handled and their population evaluated by standard microbiology
cultivation procedures. The emission spectroscopy of the discharges and TBARS (thiobarbituric acid reactive substances) absorption
spectrometric detection of the products of lipid peroxidation of bacterial cell membranes indicated a major role of radicals
and reactive oxygen species among the bio-decontamination mechanisms. 相似文献
88.
89.
90.