全文获取类型
收费全文 | 150篇 |
免费 | 5篇 |
专业分类
化学 | 124篇 |
力学 | 4篇 |
数学 | 14篇 |
物理学 | 13篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2019年 | 3篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 4篇 |
2012年 | 7篇 |
2011年 | 10篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2003年 | 9篇 |
2002年 | 5篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1957年 | 2篇 |
1940年 | 1篇 |
1916年 | 1篇 |
1914年 | 1篇 |
1913年 | 1篇 |
1909年 | 7篇 |
1904年 | 1篇 |
1903年 | 6篇 |
1902年 | 3篇 |
1900年 | 4篇 |
1898年 | 3篇 |
1895年 | 3篇 |
1890年 | 1篇 |
1887年 | 5篇 |
1886年 | 1篇 |
1885年 | 5篇 |
1884年 | 4篇 |
1882年 | 1篇 |
1881年 | 2篇 |
1879年 | 1篇 |
1878年 | 1篇 |
1870年 | 1篇 |
1865年 | 1篇 |
排序方式: 共有155条查询结果,搜索用时 15 毫秒
21.
22.
23.
Daniela M. Nolasco Isabel C. P. Fortes Eugênia R. Valadares 《Biomedical chromatography : BMC》2020,34(11):e4931
Quantitative analysis of amino acids in blood and urine is primarily indicated for the diagnosis of amino acid disorders. The high-performance liquid chromatography (HPLC) technique is frequently used for this detection. The frequency of sample collection on filter paper has been increasing exponentially, and there are many advantages attributed to processing biological samples in this way. The aim of this study was to validate a quantitative analysis of amino acids by HPLC in blood and urine collected on filter paper and to establish reference values in the neonatal period. Dried blood and dried urine samples of respectively 58 and 45 healthy newborns (2–9 days) were collected. Pre-treatment and extraction of samples were done according to the literature. Separation and analysis of amino acids were carried out by HPLC with fluorescence detection. The developed method demonstrated excellent separation, linearity, limits of detection and quantification, repeatability and recovery. The reference values for 17 amino acids were defined in dried blood and urine samples of newborns. This work presents a simple, fast and effective method for the simultaneous analysis of 17 amino acids in blood and urine collected on filter paper in a single run. The reference values were established and validated. 相似文献
24.
The effects of reaction conditions on the labelling of model proteins (human IgG and BSA) with an acridinium hydroxsuccinimidyl ester are studied. The effect of changes in reaction temperature were minimal. An increase in reaction time increased the amount of labelling, eventually reaching saturation. A higher label/protein ratio produced a proportionally higher label incorporation. The optimal pH of the labelling buffer was found to be pH 8.5. The acridinium-labelled proteins can be detected and quantified in the 4 × 10?18?3 × 10?14 mol range. 相似文献
25.
Eugen Schobig Eug Varenne und Em. Hebré 《Fresenius' Journal of Analytical Chemistry》1878,17(1):346-349
Ohne Zusammenfassung 相似文献
26.
Alan G. Gonçalves Diogo R. B. Ducatti T. Bruce Grindley M. Eugênia R. Duarte Miguel D. Noseda 《Journal of the American Society for Mass Spectrometry》2010,21(8):1404-1416
We have prepared a number of isomeric red seaweed galactan-derivative sulfated oligosaccharides to determine whether there
were diagnostic differences among the isomeric mass spectra obtained using ESI CID MS/MS (triple quadrupole instrument). Fragmentation
of the single or multicharged molecular ions from di-, tetra-, and hexasaccharides indicated that the relative positioning
of the sulfate groups and type of monosaccharide unit affect the rate of cleavage of the glycosidic bonds. We also performed
a comparative [M-Na]− fragmentation study of positional isomers of sulfated disaccharides that present all four monosulfation possibilities on
the galactopyranosidic ring. In this case, negative-ion ESI CID MS/MS approach gave diagnostic product ions from cross-ring
cleavages along with the same main B1 ion (from sulfated Galp), at m/z 241, for all isomers. The isomeric disaccharides were also submitted to increased spray energy conditions inducing in-source
fragmentation; preformed B1 ions were then fragmented to give similar product ions as those found in [M-Na]− analysis. Evaluation of the relative abundances mainly for cross-ring fragment ions at m/z 138, 139, 151, 153 allowed clear distinction among the members of the disaccharide series. The different ratios for m/z 151/153 ions were consistent with the predominance of m/z 153 being related to the cases when the bond involved in the cleavage process links a sulfated carbon. A quadrupole ion trap
instrument (MSn analysis) was also utilized to compare the results obtained with the triple quadrupole instrument. 相似文献
27.
1H NMR-based metabolomics approach for exploring urinary metabolome modifications after acute and chronic physical exercise 总被引:1,自引:0,他引:1
C. Enea F. Seguin J. Petitpas-Mulliez N. Boildieu N. Boisseau N. Delpech V. Diaz M. Eugène B. Dugué 《Analytical and bioanalytical chemistry》2010,396(3):1167-1176
Metabolomics is a comprehensive method for metabolite assessment that involves measuring the overall metabolic signature of
biological samples. We used this approach to investigate biochemical changes due to acute and chronic physical exercise. Twenty-two
women using identical oral contraceptives were segregated into an untrained (n = 10) or trained (n = 12) group depending on their physical training background. The subjects performed two exercises in a randomized order:
a prolonged exercise test (75% of their
\mathop V· \textO2 max \mathop V\limits^\cdot {{\text{O}}_{2\,\;\max }} until exhaustion) and a short-term, intensive exercise test (short-term, intensive exercise anaerobic test). Urine specimens
were collected before and 30 min after each test. The samples were analyzed by 1H NMR spectroscopy, and multivariate statistical techniques were utilized to process the data. Distinguishing characteristics
were observed only in the urine profiles of specimens collected before vs. 30 min after the short-term, intensive exercise
test. The metabolites responsible for such changes were creatinine, lactate, pyruvate, alanine, β-hydroxybutyrate, acetate,
and hypoxanthine. In both groups, the excretion of lactate, pyruvate, alanine, β-hydroxybutyrate, and hypoxanthine increased
similarly after the completion of the short-term, intensive exercise test (p < 0.03). However, acetate excretion increased to a lesser extent in trained than in untrained subjects (p < 0.05). In conclusion, metabolomics is a promising tool in order to gain insight into physiological status and to clarify
the changes induced by short-term, intense physical exercise. 相似文献
28.
Marta?PascoalEmail author M.?Eugénia?Captivo Jo?o?Clímaco 《4OR: A Quarterly Journal of Operations Research》2003,1(3):243-255
In this paper a variant of Murtys algorithm for ranking assignments according to cost is presented. It is shown that the worst-case computational complexity is better in this variant than in the original form of the algorithm. Computational results comparing three methods for ranking assignments are reported. They show that the behaviour of the new variant is also better in practice.Received: March 2003, Revised: March 2003, AMS classification:
90C27, 05C85Marta Pascoal: The research of Marta Pascoal was developed within CISUC and partially supported by the Portuguese Ministry of Science and Technology (MCT), under PRAXIS XXI Project of JNICT. 相似文献
29.
30.
da Silva Bruno Fonseca da Silva Karolayne Esthefany Melo de Farias Emerson Emiliano Gualberto de França Elvis Joacir Martins Mônica Cristina Barroso de Oliveira Santos Mariana Luiza de Lourdes Lacerda Buril Maria da Silva Alves Gustavo Gabriel de Oliveira Silva Andrezza Karla de Lira Júnior Ednaldo Barbalho da Silva Nicácio Herique Pereira Eugênia C. 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(9):3671-3679
Journal of Radioanalytical and Nuclear Chemistry - This study aimed to evaluate the effects of the Rn-222 progeny on the lichen Cladonia verticillaris under controlled conditions. The results... 相似文献