全文获取类型
收费全文 | 132篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
化学 | 100篇 |
力学 | 4篇 |
数学 | 3篇 |
物理学 | 27篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 6篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 5篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 5篇 |
2003年 | 1篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1972年 | 12篇 |
1971年 | 6篇 |
1970年 | 11篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有134条查询结果,搜索用时 203 毫秒
1.
2.
3.
R.S. Sapienza P.E. Riley R.E. Davis R. Pettit 《Journal of organometallic chemistry》1976,121(2):C35-C40
A general synthesis for the preparation of medium sized cycloalkanes having 1,2-butadienyl substituents is described. The reaction sequence involved acylation of butadiene-iron tricarbonyl with a diacid chloride, reduction of the resultant diketone to a diol derivative and conversion with HBF4 to an acyclic bis-pentadienyl Fe(C0)3 dicationic complex. Upon treatment with zinc the dication undergoes intramolecular ring closure to afford the bis-Fe(C0)3 complex of the 1,2-dibutadienyl cycloalkane. Five-, six- and ten-membered cyclolalkene derivatives have been prepared in this manner. 相似文献
4.
A brief discussion is given of some factors that merit consideration in the analysis of peptides by mass spectrometry, with emphasis on sequence determination. The first systematic study of simple peptides by field ionization (FI) is described, and comparison made with the corresponding electron-impact (EI) ionization spectra, both at low resolution (approx. 1500). The substances examined were either benzyloxycarbonyl or t-butyloxycarbonyl derivatives of di-through pentapeptide methyl esters, containing the amino acids glycine, alanine, leucine, serine, threonine, proline and tyrosine. The incidences of sequence-characteristic cleavage peaks and rearrangement ion peaks were both slightly lower in the FI than the EI spectra, although the peak relative intensities generally were higher under FI conditions. 相似文献
5.
6.
Bekzat ABDIKADYR Alp KILI Onur ALEV Serkan BÜYÜKK
SE Zafer Ziya
ZTÜRK 《Turkish Journal of Chemistry》2021,45(2):295
Pristine and WO3 decorated TiO2 nanorods (NRs) were synthesised to investigate n-n-type heterojunction gas sensing properties. TiO2 NRs were fabricated via hydrothermal method on fluorine-doped tin oxide coated glass (FTO) substrates. Then, tungsten was sputtered on the TiO2 NRs and thermally oxidised to obtain WO3 nanoparticles. The heterostructure was characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy. Fabricated sensor devices were exposed to VOCs such as toluene, xylene, acetone and ethanol, and humidity at different operation temperatures. Experimental results demonstrated that the heterostructure has better sensor response toward ethanol at 200 °C. Enhanced sensing properties are attributed to the heterojunction formation by decorating TiO2 NRs with WO3. 相似文献
7.
Ersen G
KTÜRK 《Turkish Journal of Chemistry》2020,44(5):1285
In this study, the catalytic activity and stability of flowerlike hybrid horseradish peroxidase (HRP) nanobiocatalyst (HRP-Cu 2+ ) obtained from Cu 2+ ions and HRP enzyme in the polymerization reaction of guaiacol were analyzed. We demonstrated that HRP-Cu 2+ and hydrogen peroxide (H 2 O 2 ) initiator showed significantly increased catalytic activity and stability on the polymerization of guaiacol compared to that of free HRP enzyme. Poly(guaiacol) was observed with quite high yields (88%) and molecular weights (38,000 g/mol) under pH 7.4 phosphate-buffered saline (PBS) conditions at 60 °C with 5 weight% of HRP-Cu 2+ loading. HRP-Cu 2+ also shows very high thermal stability and works even at 70 °C reaction temperature; free HRP enzyme denatures at that temperature. Furthermore, HRP-Cu 2+ provided considerable repeated use and showed some degree of catalytic activity, even after the fourth recycle, in the polymerization of guaiacol. 相似文献
8.
shak ERK Gzde KILI Elif
ZTÜRK engül Alpay KARAOLU Nurettin YAYLI 《Turkish Journal of Chemistry》2020,44(6):1655
The volatile components of essential oil (EO), SPME, and SPME of solvent extracts ( n -hexane, methanol, and water) obtained from fresh Serapias orientalis subsp. orientalis ( Soo ) were analyzed by GC-FID/MS. EO of Soo gave 11 compounds in the percentage of 99.97%; capronaldehyde (37.01%), 2-( E )-hexenal (23.19%), and n -nonanal (19.05%) were found to be major constituents. SPME GC-FID/MS analyses of fresh plant and solvent extracts of Soo revealed 7, 12, 7, and 4 compounds within the range of 99.7% to 99.9%. Limonene (76.5%, 41.7%, and 61.3%) was the major compound in SPMEs of the n -hexane and methanol extracts. α -Methoxy- p -cresol (52.9%) was the main component in its water extract. The antimicrobial activity of EO and the solvent extracts of Soo were screened against 9microorganisms. EO showed the best activity against Mycobacterium smegmatis , with 79.5 µg/mL MIC value. The n -hexane, methanol, and water extracts were the most active against the Staphylococcus aureus within the range of 81.25–125.0 µg/mL (MIC). IC 50 values for the lipase enzyme inhibitory activity of EO and solvent extracts ( n -hexane, methanol, and water) were determined to be 59.87 µg/mL, 64.03 µg/mL, 101.91 µg/mL, and 121.24 µg/mL, respectively. 相似文献
9.
10.