全文获取类型
收费全文 | 969篇 |
免费 | 20篇 |
国内免费 | 9篇 |
专业分类
化学 | 832篇 |
晶体学 | 8篇 |
力学 | 6篇 |
数学 | 24篇 |
物理学 | 128篇 |
出版年
2023年 | 5篇 |
2020年 | 10篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 10篇 |
2015年 | 11篇 |
2014年 | 32篇 |
2013年 | 60篇 |
2012年 | 49篇 |
2011年 | 52篇 |
2010年 | 35篇 |
2009年 | 30篇 |
2008年 | 58篇 |
2007年 | 53篇 |
2006年 | 64篇 |
2005年 | 51篇 |
2004年 | 45篇 |
2003年 | 60篇 |
2002年 | 58篇 |
2001年 | 24篇 |
2000年 | 18篇 |
1999年 | 15篇 |
1998年 | 10篇 |
1997年 | 13篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 13篇 |
1984年 | 14篇 |
1983年 | 4篇 |
1982年 | 12篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1978年 | 14篇 |
1977年 | 12篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1974年 | 13篇 |
1973年 | 8篇 |
1965年 | 3篇 |
排序方式: 共有998条查询结果,搜索用时 15 毫秒
91.
Masahiro Yoshida Tsutomu Matsui Yasuo Hatate Takayuki Takei Koichiro Shiomori Shiro Kiyoyama 《Journal of polymer science. Part A, Polymer chemistry》2008,46(5):1749-1757
Nylon‐polystyrene microcapsules with immobilized ferroelectric liquid crystalline segments were prepared, and permeability control of an encapsulated core material was investigated under an external electric field. A ferroelectric liquid crystal monomer possessing both mesogenicity and chirality responded effectively to the external electrical field. Permeation of the material (oxprenolol) contained in the inner aqueous core of the microcapsules was enhanced under a weak electric field (2 V). Furthermore, the permeability of oxprenolol did not depend on the external electric field in the absence of the ferroelectric liquid crystal segments. To clarify the controlled‐release mechanism of the core material, the light transmittance of the polymer membranes was quantitatively evaluated under an external electric field using a handmade polarized light transmittance apparatus. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1749–1757, 2008 相似文献
92.
93.
94.
95.
Takanari Togashi Mitsuo Umetsu Takashi Naka Satoshi Ohara Yoshiharu Hatakeyama Tadafumi Adschiri 《Journal of nanoparticle research》2011,13(9):3991-3999
The assembly of metal oxide nanoparticles (NPs) on a biomolecular template by a one-pot hydrothermal synthesis method is achieved
for the first time. Magnetite (Fe3O4) nanoneedles (length: ~100 nm; width: ~10 nm) were assembled on cyclic-diphenylalanine (cFF) nanorods (length: 2–10 μm; width:
200 nm). The Fe3O4 nanoneedles and cFF nanorods were simultaneously synthesized from FeSO4 and l-phenylalanine by hydrothermal synthesis (220 °C and 22 MPa), respectively. The samples were analyzed by powder X-ray diffraction
(XRD), Fourier transform infrared spectroscopy (IR), transmission electron microscopy (TEM), and superconducting quantum interference
device (SQUID) magnetometry. Experimental results indicate that Fe3O4 nanoneedles were assembled on cFF nanorods during the hydrothermal reaction. The composite contained 3.3 wt% Fe3O4 nanoneedles without any loss of the original magnetic properties of Fe3O4. 相似文献
96.
Masahiro Ishino Kaoru Kinoshita Kunio Takahashi Takashi Sugita Motoo Shiro Kimiko Hasegawa Kiyotaka Koyama 《Tetrahedron》2012,68(41):8572-8576
Three novel diterpenes, phomactins K–M (1–3), were isolated from the cultures of an unidentified marine-derived fungus. The structures of 1–3 were elucidated from spectroscopic data (NMR, MS, IR), and the absolute configurations of 1, 2, and the relative configuration of 3 were determined by X-ray diffraction analysis. 相似文献
97.
98.
Hironori FukumotoTomoyuki Esumi Jun IshiharaSusumi Hatakeyama 《Tetrahedron letters》2003,44(44):8047-8049
The first total synthesis of (±)-erythravine was achieved in thirteen steps from 3,4-dimethoxyphenethylamine using ring closing dienyne metathesis as the key step. 相似文献
99.
In order to resolve the long-standing issue of how itinerant ferromagnetism is affected by lattice structure and Hund's coupling, we compare various three-dimensional lattice structures in the single- and multiorbital Hubbard models with the dynamical mean-field theory with an improved quantum Monte Carlo algorithm that preserves the spin-SU(2) symmetry. The result indicates that both the lattice structure and the d-orbital degeneracy are essential for the ferromagnetism in the parameter region representing a transition metal. Specifically, (a) Hund's coupling, despite the common belief, is important, which is here identified to come from particle-hole scatterings, and (b) the ferromagnetism is a correlation effect (outside the Stoner picture) as indicated from the band-filling dependence. 相似文献
100.
Hiroki Hirai Kiichi Nakajima Soichiro Nakatsuka Kazushi Shiren Jingping Ni Shintaro Nomura Toshiaki Ikuta Takuji Hatakeyama 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(46):13785-13789
The development of a one‐step borylation of 1,3‐diaryloxybenzenes, yielding novel boron‐containing polycyclic aromatic compounds, is reported. The resulting boron‐containing compounds possess high singlet‐triplet excitation energies as a result of localized frontier molecular orbitals induced by boron and oxygen. Using these compounds as a host material, we successfully prepared phosphorescent organic light‐emitting diodes exhibiting high efficiency and adequate lifetimes. Moreover, using the present one‐step borylation, we succeeded in the synthesis of an efficient, thermally activated delayed fluorescence emitter and boron‐fused benzo[6]helicene. 相似文献