全文获取类型
收费全文 | 82篇 |
免费 | 10篇 |
国内免费 | 14篇 |
专业分类
化学 | 97篇 |
晶体学 | 1篇 |
综合类 | 1篇 |
物理学 | 7篇 |
出版年
2021年 | 6篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 8篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 9篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有106条查询结果,搜索用时 46 毫秒
31.
A single, small glycerol-containing lipid sample (50–200 nmoles) after a mild hydrolysis could be used for analysis of fatty acids, glycerol, and phosphorus. The range of the assays was from 10–500 nmoles for each lipid. 相似文献
32.
Human blood coagulation factor XI (FXI) is a key enzyme in the amplification phase of blood coagulation cascade,and is recognized as an important target for anti-coagulant deve-lopment in recent years.We designed a new mutant form of FXIa catalytic domain rhFXI 370~607 (N73Q-N113Q-C123S),and report here the facile preparation,protein crystallization,and crystal structure of this protein.We highlight a few unique structural features of FXIa after comparison with the trypsin family serine proteases at sequence and structural levels.This work provides a foundation to develop new small molecular FXIa inhibitors with increased potency and specificity. 相似文献
33.
34.
Panagiotis Theodosis-Nobelos Georgios Papagiouvannis Paraskevi Tziona Panos N. Kourounakis Eleni A. Rekka 《Molecules (Basel, Switzerland)》2021,26(13)
A series of L-serine amides of antioxidant acids, such as Trolox, (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid (phenolic derivative of cinnamic acid) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (structurally similar to butylated hydroxytoluene), was synthesized. The hydroxy group of serine was esterified with two classical NSAIDs, ibuprofen and ketoprofen. The Trolox derivatives with ibuprofen (7) and ketoprofen (10) were the most potent inhibitors of lipid peroxidation (IC50 3.4 μΜ and 2.8 μΜ), several times more potent than the reference Trolox (IC50 25 μΜ). Most of the compounds decreased carrageenan-induced rat paw edema (37–67% at 150 μmol/kg). They were moderate inhibitors of soybean lipoxygenase, with the exception of ibuprofen derivative 8 (IC50 13 μΜ). The most active anti-inflammatory compounds exhibited a significant decrease in lipidemic indices in the plasma of Triton-induced hyperlipidemic rats, e.g., the most active compound 9 decreased triglycerides, total cholesterol and low-density lipoprotein cholesterol by 52%, 61% and 70%, respectively, at 150 μmol/kg (i.p.), similar to that of simvastatin, a well-known hypocholesterolemic drug. Since the designed compounds seem to exhibit multiple pharmacological actions, they may be of use for the development of agents against inflammatory and degenerative conditions. 相似文献
35.
Atsushi Nagai Bungo Ochiai Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2005,43(8):1554-1561
The secondary structure of an optically active polythiourethane [(? CH2C*H(CO2Me)NHCOS? )n] was evaluated with 1H NMR, IR, and circular dichroism (CD) spectroscopy. Hydrogen bonds between the carbonyl and NH groups in the thiourethane group constrained the main chain of the chiral polythiourethane precisely under the direction of chirality in the main chain, whereas the racemic polymer was also constrained but randomly. The secondary structure of the polythiourethane in CHCl3 changed noticeably in the presence or absence of trifluoroacetic acid, which eliminated constraining intramolecular hydrogen bonds. IR spectroscopy suggested that the secondary structure was almost identical in solid and solution states. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1554–1561, 2005 相似文献
36.
A. A. Poyarkov T. Yu. Gromovoi V. A. Pokrovskii S. A. Poyarkova V. P. Kukhar’ 《Theoretical and Experimental Chemistry》2008,44(2):75-79
Features of ion formation under the influence of laser emission under the conditions of MALDI-TOF mass spectrometry in the
glycosylated protein thrombin and the related proteases trypsin and chymotrypsin were studied for the first time. It was shown
that trypsin and chymotrypsin are ionized in the form of molecular ions with masses 23800 and 25660 Da respectively. The molecular
ion of thrombin was not detected; three main fragment ions with masses 9951, 10230, and 11982 Da were detected in the mass
spectrum of thrombin. It was suggested that these fragments relate to peptide and glycopeptides fragment ions formed as a
result of bond cleavage in the region of Asn60G during exposure to laser emission under the conditions of MALDI-TOF mass spectrometry.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 44, No. 2, pp. 74–78, March–April, 2008. 相似文献
37.
Chuleeporn Bungthong Colin Wrigley Thanathat Sonteera Sirithon Siriamornpun 《Molecules (Basel, Switzerland)》2021,26(11)
We compared the efficacy for protein extraction of water versus enzymatic extraction. The amino-acid composition, inhibitory activity against enzymes α-amylase and α-glucosidase, and anti-glycation activities of silk protein extract (SPE) were determined. We used water extraction (100 °C, six hours) and protease-enzymatic extraction. The microstructure of silk fibers was obviously different after extraction. The results showed that enzymatic extraction gave the greater values of protein content, amino acids, total phenolic content (TPC), and total flavonoid content (TFC), as well as all biological activities parameters tested, but it also provided a more bitter taste in the extract—contributing amino acids of 51% (arginine, phenylalanine, histidine, valine, tryptophan, isoleucine, and leucine) and less sweet and umami taste contributing amino acids than did water extraction, which could be more suitable to be used as concentrated nutraceuticals. 相似文献
38.
以对叔丁基苯酚为原料,经环化缩合、脱叔丁基、酚羟基醚化、甲酰化和氧化反应制得5-羧基-25,26,27,28-四正丙基杯[4]芳烃(5);5与O-苄基-N-苄氧羰基丝氨酸反应制得5-(O-丝氨酸)-25,26,27,28-四正丙基杯[4]甲酸酯(7),其结构经~1H NMR,~(13)C NMR和MS(ESI)表征。研究了溶剂和水的用量对7催化性能的影响。结果表明:水为溶剂,其用量为10 eq.时,收率和非对映选择性分别为95%和3∶97 dr;当水的用量为30 eq.时,收率和非对映选择性分别为93%和98∶2 dr。 相似文献
39.
In this work, 0.08 mmol L−1 of phthalic acid was introduced as a mobile phase additive to quantify free amino acids (AAs) by hydrophilic interaction liquid chromatography (HILIC) coupled with electrospray ionization tandem mass spectrometry (ESI-MS/MS). The addition of phthalic acid significantly increased the signal intensity of protonated AA ions, resulting from the decrease of the relative abundance of AA sodium adducts. Meanwhile, the chromatographic peak shapes of AAs were optimized. As a consequence, there was a noticeable increase in the sensitivity of detection for AAs. The limits of detection (LOD) and quantification (LOQ) of the AAs ranged from 0.0500 to 20.0 ng mL−1 and from 0.100 to 50.0 ng mL−1, respectively, which were 4–50 times lower compared to the values measured without the addition of phthalic acid. The enhanced detection and separation of AAs were obtained by merely adding phthalic acid to the mobile phase without changing other conditions. Eventually, this simple method was validated and successfully applied to the analysis of twenty-four kinds of free AAs in human thyroid carcinoma and para-carcinoma tissues, demonstrating a significant increase of most AAs in thyroid carcinoma tissues (p < 0.05). 相似文献
40.