全文获取类型
收费全文 | 172篇 |
免费 | 6篇 |
专业分类
化学 | 109篇 |
晶体学 | 1篇 |
力学 | 2篇 |
数学 | 23篇 |
物理学 | 43篇 |
出版年
2023年 | 1篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 10篇 |
2009年 | 4篇 |
2008年 | 11篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 12篇 |
2003年 | 13篇 |
2002年 | 10篇 |
2001年 | 6篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1967年 | 1篇 |
排序方式: 共有178条查询结果,搜索用时 15 毫秒
1.
Adsorption characteristics of bisphenol A onto carbonaceous materials produced from wood chips as organic waste 总被引:1,自引:0,他引:1
Nakanishi A Tamai M Kawasaki N Nakamura T Tanada S 《Journal of colloid and interface science》2002,253(2):393-396
A single-chain amphiphile containing a rigid Schiff base segment, 3-cyano-N-benzylidene hexadecylamine (CNBHB) in the polar head group was synthesized and studied for its vesicle-forming properties. The dependence of the aggregation behavior of the vesicles as such and in the presence of manganese ions were studied as a function of temperature using differential scanning calorimetry and turbidity measurements. Transmission electron microscopy (TEM) was used to analyze the morphology of the vesicles, showed interesting features with fusion of regular structures, and were quite stable. In the presence of manganese ions, fusion of vesicles takes place. This could be due to the metal ions that are bound to the surface of the vesicles that cause a partial destruction of the hydration shell on the surface of the vesicles. The reduction in the hydration force could thus be responsible for the fusion. 相似文献
2.
Kuroda N Hattori T Fujioka Y Cork DG Kitada C Sugawara T 《Chemical & pharmaceutical bulletin》2001,49(9):1147-1154
An in-house developed automated synthesis suite was used to prepare a library of 72 tetrapeptide derivatives, the starting materials for pharmaceutically attractive pentapeptides, employing a convergent strategy. An initial set of 18 dipeptides were synthesized on a large-scale (100-1000 g) using automated synthesis workstations, and then 72 tetrapeptides were synthesized on a medium scale (5-10 g) using an automated system. Each di- or tetrapeptide was prepared in a single operating cycle using a modified methanesulfonic acid method, then a sub-library of 56 pentapeptides were synthesized in parallel, on a small-scale (100 mg-1 g) using a robotic workstation. 相似文献
3.
Fujita M Nakao Y Matsunaga S Seiki M Itoh Y Yamashita J Van Soest RW Fusetani N 《Journal of the American Chemical Society》2003,125(51):15700-15701
A novel MMP inhibitor, ageladine A (1) with antiangiogenic activity was isolated from a marine sponge Agelas nakamurai. Structure 1 was determined by a combination of spectroscopic and chemical methods to be an unprecedented structure of 4-(4,5-dibromo-1H-pyrrol-2-yl)]-1H-imidazo[4,5-c]pyridin-2-amine. 相似文献
4.
Distribution of pirarubicin in human blood. 总被引:1,自引:0,他引:1
K Nagasawa N Kitada C Tsuji M Ogawa T Yokoyama N Ohnishi S Iwakawa K Okumura 《Chemical & pharmaceutical bulletin》1992,40(10):2866-2869
We investigated the distribution and stability of pirarubicin in human blood obtained from 12 healthy volunteers. The distribution of pirarubicin into blood cells showed marked temperature- and concentration-dependencies and the Arrhenius plot for pirarubicin uptake in blood was biphasic. Therefore, pirarubicin appears to be taken up into blood cells by a carrier-mediated system. Pirarubicin was mainly enzymatically metabolized to pirarubicinol in blood cells, but pirarubicin was not metabolized into doxorubicin in either blood or plasma. On the other hand, in plasma, pirarubicin was degraded to unknown inactive compounds instead of pirarubicinol. It is therefore suggested that blood cells serve to protect against the degradation of pirarubicin into inactive compounds in blood. Accordingly, when the monitoring of pirarubicin and its active metabolites is carried out in patients, both blood and plasma must be frozen immediately after blood collection. 相似文献
5.
A flow analysis system involving the on-line configuration of an anion-exchange column has been examined to enrich and determine trace concentrations of zirconium of several ppm to hundred ppm levels in silicate rocks and minerals. About 100 mg of sample is decomposed by fusion with a mixture of boric acid and lithium carbonate and taken up with 1M hydrochloric acid to a total of 100 ml. Depending upon the concentration of zirconium, either a 1- or 4-ml aliquot is introduced into an aqueous carrier stream, merged with sulphuric acid and passed through a small volume anion-exchange column. The enriched zirconium is then back eluted with hydrochloric acid, colour-developed with Arsenazo III, and detected spectrophotometrically at 665 nm. 相似文献
6.
[reaction: see text] Chiral C(4)-substituted (E)- or (Z)-1-alkynyl-1-trimethylsilyloxy-2-butene systems provide anti-(Z) or syn-(Z) conjugated dienyne, with a very high level of stereocontrol, on treatment with BF(3).OEt(2) in CH(2)Cl(2) at -50 degrees C in the presence of allyltrimethylsilane. The Cieplak conformation for (E)-substrates and neighboring-group participation for (Z)-substrates are considered to be responsible for the stereochemical consequences. 相似文献
7.
Hideo?AkisadaEmail author Masakatu?Ishihara Mitiko?Nishi Masaaki?Higake Seiki?Ishimaru Junko?Nishida 《Colloid and polymer science》2003,281(10):993-997
The partial molal volumes of two series of homologous surfactants, n-alkylammonium decanesulfonates and a, ?-alkanediammonium nonanesulfonates, were measured below and above their CMC in aqueous solution. Their counterions were n-alkylammonium and a, ?-alkanediammonium. The relationship between the partial molal volume and the chain length of the counterion below the CMC had an inflection point. The relationship between them, above the CMC, was almost linear. In the case of the alkylammonium salts, the values of the volume change of micellization were almost the same when the chain length of the counterions was shorter than the butyl, and increased with an increase in the chain length when it was longer than the propyl. In the case of the alkanediammonium salts, the volume change of micellization showed a small decrease with the chain length when it was shorter than octane, and was very large for the nonane ammonium salt. The large positive increase in the volume change with the increase in the chain length of the counterion can be explained by the hydrophobic interaction between the alkyl chain of the counterion and the hydrophobic core of the micelle. 相似文献
8.
[reaction: see text] This paper describes a novel method to synthesize a quinoline backbone by incorporating allenyl cations into a catalytic intramolecular Friedel-Crafts reaction. The initial products were isomerized and aromatized upon treatment with acid and base, respectively, to give quinolines. The basic concept also proved to be promising for 1-benzazepine, 1-benzazocine, or isoquinoline synthesis. 相似文献
9.
Total Synthesis of the Antibiotic Kendomycin: A Macrocyclization Using the Tsuji–Trost Etherification
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Tetsuya Sengoku Dr. Shu Xu Kenji Ogura Yoshinori Emori Kenji Kitada Prof. Dr. Daisuke Uemura Prof. Dr. Hirokazu Arimoto 《Angewandte Chemie (International ed. in English)》2014,53(16):4213-4216
A highly stereocontrolled, convergent total synthesis of kendomycin [(?)‐TAN2162], an ansa‐macrocyclic antibiotic, is reported. The key of the strategy is an unprecedented Tsuji–Trost macrocyclic etherification, followed by a transannular Claisen rearrangement to construct the 18‐membered carbocyclic framework. The oxa‐six‐ and five‐membered rings were also stereoselectively constructed respectively by a cascade oxidative cyclization at an unfunctionalized benzylic position and using a one‐pot epoxidation/5‐exo‐tet epoxide opening. 相似文献
10.
Murrae J. Bowden Antoni S. Gozdz Joseph M. DeSimone James E. McGrath Seiki Ito Minoru Matsuda 《Macromolecular Symposia》1992,53(1):125-137
The various chemical approaches aimed at improving the reactive-ion etch resistance of poly(olefin sulfone)s are described. Resist systems based on incorporation of RIE-resistant moieties via random copolymerization, blending and block copolymer formation are described and lithographic properties noted. 相似文献