全文获取类型
收费全文 | 161篇 |
免费 | 6篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 40篇 |
金属工艺 | 7篇 |
机械仪表 | 6篇 |
建筑科学 | 3篇 |
能源动力 | 1篇 |
轻工业 | 15篇 |
石油天然气 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 39篇 |
冶金工业 | 16篇 |
自动化技术 | 21篇 |
出版年
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 11篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 13篇 |
2012年 | 10篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有171条查询结果,搜索用时 31 毫秒
11.
12.
The International Conference on Titanium was begun in 1968 to assess the national significance attached to the development
of titanium in relation to the technical needs of the participating countries. The conference, held every four years, attracts
strong international participation. This article reviews the 12th World Conference on Titanium, hosted by the Nonferrous Society of China and held in Beijing, China, 19–24 June 2011. 相似文献
13.
Sutrisno A Ueda M Inui H Kawaguchi T Nakano Y Arai M Miyatake K 《Journal of Bioscience and Bioengineering》2001,91(6):599-602
A gene encoding chitinase from Aeromonas sp. no. 10S-24 was expressed using pTrc99A in Escherichia coli JM 105 which yielded a 5-fold higher activity than when pUC19 was used. Three different truncated enzymes (SA-1, SA-2 and SA-3) were obtained after purification. Their isoelectric points were 7.0, 6.9, and 6.7, respectively. The enzymes showed two optimum pHs, 4.0 and 7.0, when incubated with ethylene glycol chitin as the substrate, and were stable over a wide pH range (3.0-9.0). The optimum temperature was 60 degrees C and the enzymes were stable up to 50 degrees C. The chitinases exhibited wide substrate specificities for chitin-related compounds. 相似文献
14.
Grapefruit juice is consumed widely in today's health conscious world as a protector against cardiovascular diseases and cancers.
It has however, been found to be an inhibitor of the intestinal cytochrome P – 450 3A4 system, which is responsible for the
first pass metabolism of many drugs. The P – glycoprotein pump, found in the brush border of the intestinal wall which transports
many of these cytochrome P – 450 3A4 substrates, has also been implicated to be inhibited by grapefruit juice. By inhibiting
these enzyme systems, grapefruit juice alters the pharmacokinetics of a variety of medications, leading to elevation of their
serum concentrations. Most notable are its effects on the calcium channel antagonist and the statin group of drugs. In the
case of many drugs, the increased serum concentration has been found to be associated with increased frequency of dose dependent
adverse effects. In this review, we have discussed the phytochemistry of grapefruit juice, the various drugs involved in the
drug – grapefruit juice eraction with their mechanisms of action and have presented the clinical implications of these interactions. 相似文献
15.
Bor‐Sen Chiou Haani Jafri Trung Cao George H. Robertson Kay S. Gregorski Syed H. Imam Greg M. Glenn William J. Orts 《应用聚合物科学杂志》2013,129(6):3192-3197
Wheat gluten was reacted with citric acid to produce natural superabsorbent materials able to absorb up to 78 times its weight in water. The properties of the modified gluten samples were characterized using Fourier Transform Infra‐red (FTIR) spectroscopy, thermogravimetric analysis, and water uptake. The reaction between gluten and citric acid was examined for gluten : citric acid ratios of 0.38 : 1 to 0.75 : 1 at temperatures from 100 to 130°C. More citric acid reacted for samples containing higher citric acid concentrations and at higher temperatures. FTIR analyses indicated the presence of carboxylate groups on the modified gluten samples, which resulted in modified samples having higher water uptake values than neat gluten. The sample with a gluten:citric acid ratio of 0.5 : 1 and reaction temperature of 120°C had the largest water uptake value. Also, all modified gluten samples had lower thermal stability than neat gluten. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
16.
Bor‐Sen Chiou George H. Robertson LuAnn E. Rooff Trung Cao Haani Jafri Kay S. Gregorski Syed H. Imam Greg M. Glenn William J. Orts 《应用聚合物科学杂志》2010,116(5):2638-2644
Wheat gluten films of various thicknesses formed at 30–70°C were treated with cold sulfuric acid to produce sulfated gluten films. Chemical, thermal, thermal stability, and water uptake properties were characterized for neat and sulfated films. The sulfated gluten films were able to absorb up to 30 times their weight in deionized water. However, this value dropped to 3.5 when the film was soaked in a 0.9% (w/w) NaCl solution. The films were also soaked 4 times in deionized water, and each soaking resulted in a reduced water uptake capacity. The temperature of film formation had no effect on the final water uptake properties. Also, thinner films had higher concentrations of sulfate groups than thicker films; this resulted in higher water uptake values. In addition, sulfated gluten films had comparable glass‐transition temperatures but lower thermal stabilities than the neat gluten films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
17.
Morsyleide F. Rosa Bor‐sen Chiou Eliton S. Medeiros Delilah F. Wood Luiz H. C. Mattoso William J. Orts Syed H. Imam 《应用聚合物科学杂志》2009,111(2):612-618
Unripe coconut fibers were used as fillers in a biodegradable polymer matrix of starch/ethylene vinyl alcohol (EVOH)/glycerol. The effects of fiber content on the mechanical, thermal, and structural properties were evaluated. The addition of coconut fiber into starch/EVOH/glycerol blends reduced the ductile behavior of the matrix by making the composites more brittle. At low fiber content, blends were more flexible, with higher tensile strength than at higher fiber levels. The temperature at the maximum degradation rate slightly shifted to lower values as fiber content increased. Comparing blends with and without fibers, there was no drastic change in melt temperature of the matrix with increase of fiber content, indicating that fibers did not lead to significant changes in crystalline structure. The micrographs of the tensile fractured specimens showed a large number of holes resulting from fiber pull‐out from the matrix, indicating poor adhesion between fiber and matrix. Although starch alone degraded readily, starch/EVOH/glycerol blends exhibited much slower degradation in compost. Composites produced 24.4–28.8% less CO2 compared with starch in a closed‐circuit respirometer. Addition of increasing amount of fiber in starch/EVOH/glycerol composite had no impact on its biodegradation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
18.
19.
20.
Pure geometric isomers of conjugated linoleic acid were prepared from castor oil as the primary starting material. Methyl octadeca-9Z,11E-dienoate (2) and methyl octadeca-9Z,11Z-dienoate (4) were obtained by zinc reduction of methyl santalbate (1, methyl octadec-11E-en-9-ynoate) and methyl octadec-11Z-en-9-ynoate (3), respectively, as the key intermediates. Methyl octadeca-9E,11E-dienoate (8) and methyl octadeca-9E,11Z-dienoate (9) were prepared by demesylation of the mesyloxy derivative of methyl ricinelaidate (6, methyl 12-hydroxy-octadec-9E-enoate). A study of the nuclear magnetic resonance spectral properties was carried-out, and the shifts of the olefinic carbon atoms of 18:2(9Z,11E) (2) and 18:2(9E,11Z) (9) were readily identified by a combination of incredible natural abundance double quantum transfer experiment, heteronuclear multiple bond correlation, and 1H-13C correlation spectroscopy correlation techniques. Doubts remain in the absolute identification of the individual olefinic carbon atoms of the 18:2(9Z,11Z) (4) and 18:2(9E,11E) (8), except the fact that the shifts of the "inner" (C-10 and C-11) and "outer" (C-9 and C-12) positioned olefinic carbon atoms of the conjugated diene system are distinguishable. 相似文献