全文获取类型
收费全文 | 489篇 |
免费 | 8篇 |
专业分类
化学 | 402篇 |
晶体学 | 3篇 |
力学 | 5篇 |
数学 | 10篇 |
物理学 | 77篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 3篇 |
2013年 | 30篇 |
2012年 | 20篇 |
2011年 | 18篇 |
2010年 | 13篇 |
2009年 | 17篇 |
2008年 | 38篇 |
2007年 | 36篇 |
2006年 | 30篇 |
2005年 | 36篇 |
2004年 | 31篇 |
2003年 | 23篇 |
2002年 | 15篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1997年 | 4篇 |
1996年 | 12篇 |
1995年 | 6篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有497条查询结果,搜索用时 0 毫秒
81.
Yoshio Fuchita Kazuhiko Yoshinaga Tomoko Hanaki Hiroyuki Kawano Junko Kinoshita-Nagaoka 《Journal of organometallic chemistry》1999,580(2):2258
Cyclopalladation of mono-, di- and tribenzylamine has been investigated by reacting the corresponding amines with an equimolar amount of palladium(II) acetate (reaction i), or by heating the corresponding bis-amine complexes [Pd(O2CMe)2{(PhCH2)nNH3−n}2] (n=1, 2) (reaction ii). By the reaction i, all the three amines undergo cyclopalladation. However, in the case of the reaction ii, only the dibenzylamine complex [Pd(O2CMe)2{(PhCH2)2NH}2] has been converted into a cyclopalladated complex. The reactivity of the three benzylamines towards cyclopalladation has been discussed in terms of the co-ordinating ability influenced by the bulkiness around the nitrogen atom. Temperature-dependent 1H-NMR spectra are observed for mononuclear cyclopalladated complexes [Pd(O2CMe){C6H4CH2N(CH2Ph)2–C1, N}L] (L=PPh3, AsPh3) and are attributed to the dissociation of the nitrogen atom in the cyclopalladated chelate ring. A heteroleptic bis-cyclopalladated complex [Pd[C6H4CH2N(CH2Ph)2–C1, N](C6H4CH2NMe2–C1, N)] has also been prepared. X-ray crystallographic studies on [{Pd(O2CMe)[C6H4CH2N(CH2Ph)2–C1, N]}2] and [Pd[C6H4CH2N(CH2Ph)2–C1, N](C6H4CH2NMe2–C1, N)] have been reported. 相似文献
82.
Hiroyuki Kawano Tomonori Mori Yasuyuki Hirakawa Totaro Imasaka 《Optics Communications》1999,160(4-6):277-282
Stimulated Raman emission from liquid dibromomethane (vibrational Raman shift frequency, 588 cm−1) is introduced into hydrogen gas (rotational Raman shift frequency, 587 cm−1) as a seed beam, in order to generate numerous rotational lines by four-wave Raman mixing. Unexpectedly, a supercontinuum, which is generated by self-phase modulation in dibromomethane, acted as a seed beam to exclusively generate vibrational lines; the rotational lines are generated only when the supercontinuum is minimal. The former is explained by a competition between the high-gain vibrational and low-gain rotational Raman effects when strongly seeded by a supercontinuum. The latter is explained by stimulated Raman gain under the seed effect exclusively to the first-Stokes rotational line. 相似文献
83.
The in vitro synthesis of chitin via a nonbiosynthetic path has been achieved for the first time by enzymatic ring-opening polyaddition of a chitobiose oxazoline monomer ( C2O ). Chitinase, a hydrolysis enzyme of chitin, recognized and polymerized the monomer regio- and stereoselectively. The structure of artificial chitin was confirmed by comparison with an authentic natural chitin sample with the use of CP/MAS 13C NMR and IR spectroscopy. X-ray diffraction as well as NMR analysis showed its crystal structure of α-chitin. Characteristic features of the present polymerization are described. 相似文献
84.
85.
Takegawa Y Deguchi K Ito H Keira T Nakagawa H Nishimura S 《Journal of separation science》2006,29(16):2533-2540
Asparagine-linked oligosaccharides (N-glycans) usually show structural heterogeneity, especially in proteins with sialylated N-glycans and, therefore, their structural analysis is still very difficult. A zwitterionic type of hydrophilic interaction chromatography column with sulfobetaine functional groups (called a ZIC-HILIC column) was applied to the separation of tryptic peptides of alpha-1-acid glycoprotein. It was demonstrated that the ZIC-HILIC separation column has a selectivity for sialylated N-glycopeptides and a high capability for separation based on the structural recognition of sialylated N-glycan isomers as well as for the previously reported neutral N-glycans and N-glycopeptides. The retention characteristics of neutral and sialylated N-glycans derivatized with 2-aminopyridine (PA N-glycans) demonstrate that the retentions of the N-glycans are based primarily on hydrophilic interaction with the water-rich liquid layer generated on the surface of the ZIC-HILIC column. In addition, the electrostatic repulsion interaction shielded with counter ions effectively tunes the separation and recognition of sialylated N-glycan isomers. 相似文献
86.
Yoshiaki Hidaka Hiromitsu Masaoka Hidekazu Oshita Takuji Nakamura Koji Tanaka Hiroyuki Kawano 《国际化学动力学杂志》1992,24(10):871-885
The thermal decomposition of vinylacetylene (C4H4) was studied behind reflected shock waves using both a single-pulse method (reaction time between 0.8 and 3.3 ms) and a time-resolved UV-absorption method (230 nm). The studies were done over the temperature range of 1170–1690 K at the total pressure range of 1.3–2.3 atm. The mechanism was used to interpret both the early and late stages of vinylacetylene decomposition at the high temperatures. It was confirmed that C4H4 dissociation proceeded through the following three channels. The rate constant expression of reaction (1) was determined as k1 = 6.3 × 1013 exp(?87.1 kcal/RT) s?1. The rate constants of the succeeding reactions (chain reaction, C4H4 + H → i-C4H3 + H2 and C4H4 + H → C2H2 + C2H3 and decomposition reactions of free radicals, i-C4H3 + M → C4H2 + H + M) were confirmed or estimated. © John Wiley & Sons, Inc. 相似文献
87.
The magnetic property of Co2B2O5 and the optical property of M2B2O5 (M = Mn, Co) were investigated. Co2B2O5 showed antiferromagnetic behavior below the Néel temperature of TN ≈ 45 K, and the Weiss temperature was TW = +7.7 K. The effective magnetic moment of Co was 4.96 μB, which indicated that Co was divalent and in a high-spin state. Absorptions attributed to the d–d transitions in Mn2+ and Co2+ ions were observed at 250–650 nm in the diffuse reflection spectra. The optical absorption edges of Mn2B2O5 and Co2B2O5 were at 243 nm (5.11 eV) and 299 nm (4.15 eV), respectively. 相似文献
88.
Kentarou Sakamoto Dr. Misao Akishiba Takahiro Iwata Dr. Kazuya Murata Dr. Seiya Mizuno Dr. Kenichi Kawano Dr. Miki Imanishi Prof. Dr. Fumihiro Sugiyama Prof. Dr. Shiroh Futaki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20165-20173
Endocytic pathways are practical routes for the intracellular delivery of biomacromolecules. Along with this, effective strategies for endosomal cargo release into the cytosol are desired to achieve successful delivery. Focusing on compositional differences between the cell and endosomal membranes and the pH decrease within endosomes, we designed the lipid-sensitive and pH-responsive endosome-lytic peptide HAad. This peptide contains aminoadipic acid (Aad) residues, which serve as a safety catch for preferential permeabilization of endosomal membranes over cell membranes, and His-to-Ala substitutions enhance the endosomolytic activity. The ability of HAad to destabilize endosomal membranes was supported by model studies using large unilamellar vesicles (LUVs) and by increased intracellular delivery of biomacromolecules (including antibodies) into live cells. Cerebral ventricle injection of Cre recombinase with HAad led to Cre/loxP recombination in a mouse model, thus demonstrating potential applicability of HAad in vivo. 相似文献
89.
Yusuke Nakajima Takeshi Kawano Yusuke Taki Chie Kojima 《Research on Chemical Intermediates》2018,44(8):4745-4754
Collagen is a major component of the extracellular matrix, and collagen gels have been used as cell scaffolds. We previously prepared gold nanoparticle (AuNP)-embedded collagen gels (AuCol) to serve as cell scaffolds that were sensitive to visible light. We performed single cell detachment from this cell scaffold using a microscope equipped with a laser irradiation system. In the present study, we adjusted hydrogel thickness and AuNP concentration in AuCol, with a goal of improving cell detachment efficiency. Thin hydrogels became blackened after the laser irradiation, and thick hydrogels with high AuNP concentrations were not permeable to the laser light. We, therefore, prepared bilayer gels, composed of AuCol as the upper layer and intact collagen gel (Col) as the bottom layer. These bilayer gels allowed more effective cell detachment, because they were thick and optically transparent. Our results indicated that an AuCol/Col ratio of 2 enabled the highest cell detachment efficiency. Essentially, no cell damage was observed in our system, suggesting that this is a cell-friendly single cell separation system. 相似文献
90.
Osamu Kurata Norihiko Iki Takahiro Inoue Takayuki Matsunuma Taku Tsujimura Hirohide Furutani Masato Kawano Keisuke Arai Ekenechukwu Chijioke Okafor Akihiro Hayakawa Hideaki Kobayashi 《Proceedings of the Combustion Institute》2019,37(4):4587-4595
Low-NOx NH3-air combustion power generation technology was developed by using a 50-kWe class micro gas-turbine system at the National Institute of Advanced Industrial Science and Technology (AIST), Japan, for the first time. Based on the global demand for carbon-free power generation as well as recent advances involving gas-turbine technologies, such as heat-regenerative cycles, rapid fuel mixing using strong swirling flows, and two-stage combustion with equivalence ratio control, we developed a low-NOx NH3-air non-premixed combustor for the gas-turbine system. Considering a previously performed numerical analysis, which proved that the NO reduction level depends on the equivalence ratio of the primary combustion zone in a NH3-air swirl burner, an experimental study using a combustor test rig was carried out. Results showed that eliminating air flow through primary dilution holes moves the point of the lowest NO emissions to the lesser fuel flow rate. Based on findings derived by using a test rig, a rich-lean low NOx combustor was newly manufactured for actual gas-turbine operations. As a result, the NH3 single fueled low-NOx combustion gas-turbine power generation using the rich-lean combustion concept succeeded over a wide range of power and rotational speeds, i.e., below 10–40 kWe and 75,000–80,000?rpm, respectively. The NO emissions were reduced to 337?ppm (16% O2), which was about one-third of that of the base system. Simultaneously, unburnt NH3 was reduced significantly, especially at the low electrical power output, which was indicative of the wider operating range with high combustion efficiency. In addition, N2O emissions, which have a large Global Warming Potential (GWP) of 298, were reduced significantly, thus demonstrating the potential of NH3 gas-turbine power generation with low environmental impacts. 相似文献