全文获取类型
收费全文 | 107篇 |
免费 | 0篇 |
专业分类
化学 | 76篇 |
晶体学 | 1篇 |
力学 | 1篇 |
数学 | 23篇 |
物理学 | 6篇 |
出版年
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2014年 | 1篇 |
2013年 | 10篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1943年 | 1篇 |
排序方式: 共有107条查询结果,搜索用时 31 毫秒
1.
Lead has been determined in three certified reference materials (aquatic plant, olive leaves, and mussel tissue) by direct slurry atomization-graphite furnace atomic absorption spectrophotometry. The importance of using ascorbic acid as matrix modifier has been demonstrated, particularly to overcome calcium interferences. Using 0.05 M ascorbic acid and aqueous calibration standards excellent agreement was found with certified values. The method is proposed for general application in environmental analysis. 相似文献
2.
Miranda LP Lubell WD Halkes KM Groth T Grøtli M Rademann J Gotfredsen CH Meldal M 《Journal of combinatorial chemistry》2002,4(5):523-529
A novel polymer matrix for solid-phase synthesis, SPOCC(194) resin (1), was designed featuring a backbone of homogeneous tetraethylene glycol (TEG(194)) macromonomer linked by quaternary carbon junctions and terminating in primary alcohol functionality. Beaded SPOCC(194) resin was effectively prepared by suspension polymerization of oxetanylated TEG macromonomer 5 in stirred silicon oil. Mechanically stable and inert to a diverse range of reaction conditions, SPOCC(194) possessed a high hydroxyl group loading (0.9-1.2 mmol/g) for substrate attachment and swelled effectively ( approximately 2-4 mL/g) in a variety of organic and aqueous solvents. Developed for solid-phase synthesis at high reactant concentrations for driving organic and aqueous reactions to completion, SPOCC(194) exhibited high functional group density (mmol/mL) similar to that of low-loaded aminomethylated polystyrene-divinylbenzene copolymer (PS-1%DVB) yet significantly higher than that of PEGA(1900), SPOCC(1500), and TentaGel S. High-resolution MAS NMR spectra of Fmoc-derivatized SPOCC(194) indicate that monitoring of functional group transformation is possible. Moreover, by employment of a nonaromatic resin-linker combination, electrophilic chemistry, such as Lewis acid catalyzed glycosylation and Friedel-Crafts acylation, was selectively performed on substrate bound to SPOCC(194) resin. Such properties make SPOCC(194) resin a promising new polymer matrix for the support-bound construction of small organic molecules by parallel and combinatorial synthesis and the scavenging of solution-phase reactants or byproducts. 相似文献
3.
William Doherty Peter Halley Les Edye David Rogers Francisco Cardona Yoosup Park Tim Woo 《先进技术聚合物》2007,18(8):673-678
Sugarcane fiber (i.e. bagasse) lignin has a larger fraction of aromatics unsubstitution in the ortho position than hardwood or softwood lignin and hence has the greater ability to be derivatized. Furthermore, organosolv lignin has a higher purity than sulfonated and kraft lignins. This work examines the purification of organosolv lignin derived from bagasse and the physico‐chemical properties of the lignin and lignin‐phenol formaldehyde (PF) resin coatings, and composites. The wetability tests have shown that lignin and lignin‐PF resin films are effective water barrier coatings, though the contact angles of lignin‐PF resin films were considerably less than the wax films. The overall mechanical properties (i.e. peak stress, peak strain and modulus) of the bagasse fiber composites were lower than the values obtained with the composites without the inclusion of bagasse fiber. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
4.
Phosphate selective electrodes have been produced based upon rubbery membranes containing heterocylic macrocycles as sensors covalently bound to a cross-linked polystyrene-block–polybutadiene-block–polystyrene (SBS) polymer. The membranes were robust and the best HPO42−-selective membrane fabricated was composed of 7.1% (m/m) dicumyl peroxide, 28.3% (m/m) 2-nitrophenyloctylether, 9.8% (m/m) 3-(10-undecenyl)-1,5,8-triazacyclodecane-2,4-dione, 31.0% (m/m) SBS and 23.8% (m/m) PoleStar™ 200R (clay-based filler). The characteristics of this electrode were a linear Nernstian range of 3.9×10−3 to 1×10−6 mol dm−3 HPO42− with a limit of detection of 1.0×10−6 mol dm−3 HPO42−, a slope of −29.7±0.9 mV per activity decade and a pH range from 6 to 8. Selectivity coefficients for phosphate against various interfering anions (chloride, sulfate and nitrate) were determined. Response times were 2 min or under, stability of response and electrode lifetime in continuous use were also very satisfactory. The response behavior of HPO42−-ISEs based upon mobile and bound ionophores was comparable and suggests that mobility of the ionophore is not necessary to obtain a working ISE and that covalent binding of ionophores can be used to produce ISEs of increased stability and robustness. 相似文献
5.
6.
Concentrated perchloric acid is used to digest coal for subsequent determination of arsenic and selenium by hydride-generation atomic absorption and fluorescence spectrometry. Arsenic and selenium are removed from potentially interfering metal ions by coprecipitation with lanthanum hydroxide. The detection limits, 58 and 36 ng g?1 by atomic absorption and 25 and 10 ng g?1 by atomic fluorescence, for arsenic and selenium in coal, respectively, are adequate for the normal levels of these metals. 相似文献
7.
Sarah Fitzpatrick Les Ebdon Michael E. Foulkes 《International journal of environmental analytical chemistry》2013,93(11-12):835-841
A method is presented for arsenic speciation analysis of an oyster sample using ion chromatography coupled with an inductively coupled plasma mass spectrometry (ICP-MS) instrument. A strong anion exchange resin was employed with a step gradient elution of 0.1 mM/0.1 M K 2 SO 4 at pH 10.2. Arsenobetaine and dimethylarsinic acid were determined following extraction based on trypsin enzymolysis with 95-100% extraction efficiency. Limits of detection in the range 0.1-0.3 mg kg m 1 of arsenic were obtained for organic arsenic species. No inorganic arsenic was detected. Validation was performed using TORT-2 as a certified reference material. Although high performance liquid chromatography (HPLC) coupled to ICP-MS is an effective method for speciation analysis it is not always necessary to obtain such a detailed picture. A simple liquid chromatographic separation technique based upon mini-column technology is presented. It was developed to obtain a fast, efficient and reliable separation of inorganic from organic, i.e. assumed toxic from non-toxic, arsenic and selenium species suitable for use as an initial screening method for environmental analysis. Two types of strong anion exchange resin were tested. Excellent separation was obtained for both min-column resins and analysis times were within 7 min. Limits of detection obtained for inorganic arsenic, organic arsenic, selenomethionine, Se IV and Se VI were 1.6, 1.8, 66, 32 and 22 µg kg m 1 , respectively. 相似文献
8.
Wei-Gang Hu Scott Jager Damon Chau Dave Mah Les P. Nagata 《Applied biochemistry and biotechnology》2010,160(4):1206-1216
In order to develop a recombinant full-length human anti-botulinum neurotoxin A (BoNT/A) antibody, human peripheral blood
mononuclear cells (PBMC) were collected from three healthy volunteers and induced for BoNT/A-specific immune response by in
vitro immunization. The genes encoding human Fd fragment, consisting of antibody heavy chain variable region and constant
region 1 with the genes encoding antibody light chain, were cloned from the immunized PBMC. Afterwards, one combinatory human
antigen-binding fragment (Fab) library was constructed using a lambda phage vector system. The size of the constructed library
was approximately 105
Escherichia coli transformants. After screening the library by BoNT/A antigen using a plaque lifting with immunostaining approach, 55 clones
were identified as positive. The Fab gene of the most reactive clone exhibiting particularly strong BoNT/A binding signal
was further subcloned into a full-length human IgG1 antibody gene template in an adenoviral expression vector, in which the
heavy and light chains were linked by a foot-and-mouth-disease virus-derived 2A self-cleavage peptide under a single promoter.
After the full-length human IgG1 was expressed in mammalian cells and purified with protein L column, sodium dodecyl sulfate-polyacrylamide
gel electrophoresis showed that the heavy and light chains of the antibody were cleaved completely. The affinity expressed
as the dissociation constant (K
d) for the recombinant human antibody to bind to BoNT/A was determined by indirect enzyme-linked immunosorbent assay and results
confirmed that the recombinant full-length human antibody retained BoNT/A-binding specificity with K
d value of 10−7 M. 相似文献
9.
10.