全文获取类型
收费全文 | 2903篇 |
免费 | 69篇 |
国内免费 | 10篇 |
专业分类
化学 | 2191篇 |
晶体学 | 75篇 |
力学 | 50篇 |
综合类 | 1篇 |
数学 | 78篇 |
物理学 | 587篇 |
出版年
2022年 | 19篇 |
2021年 | 26篇 |
2020年 | 36篇 |
2019年 | 31篇 |
2018年 | 23篇 |
2017年 | 16篇 |
2016年 | 46篇 |
2015年 | 54篇 |
2014年 | 60篇 |
2013年 | 131篇 |
2012年 | 123篇 |
2011年 | 127篇 |
2010年 | 81篇 |
2009年 | 83篇 |
2008年 | 134篇 |
2007年 | 158篇 |
2006年 | 166篇 |
2005年 | 154篇 |
2004年 | 149篇 |
2003年 | 117篇 |
2002年 | 116篇 |
2001年 | 86篇 |
2000年 | 80篇 |
1999年 | 44篇 |
1998年 | 36篇 |
1997年 | 30篇 |
1996年 | 40篇 |
1995年 | 42篇 |
1994年 | 41篇 |
1993年 | 40篇 |
1992年 | 73篇 |
1991年 | 36篇 |
1990年 | 34篇 |
1989年 | 39篇 |
1988年 | 33篇 |
1987年 | 43篇 |
1986年 | 44篇 |
1985年 | 42篇 |
1984年 | 41篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 20篇 |
1980年 | 19篇 |
1979年 | 30篇 |
1978年 | 24篇 |
1977年 | 18篇 |
1976年 | 22篇 |
1975年 | 18篇 |
1974年 | 26篇 |
1973年 | 20篇 |
排序方式: 共有2982条查询结果,搜索用时 15 毫秒
11.
12.
A special poster session was run during the 18th International Symposium on Shock Waves, held on July 21 – 26, 1991, in Sendai, Japan. The purpose of this session was to compare various CFD schemes which are useful for simulating shock wave phenomena. A 2-D planar shock wave diffraction over a 90 degree sharp corner was selected as a bench mark problem. The problem specification and the output format are described below. Experimental outputs for the close flow conditions to the computational ones were also called for. Twenty six poster presentations were made at this session and the majority of the posters reflected a standard of excellence that warrants publication in the Shock Waves journal. Therefore these results are reproduced here. However, since there is a limit on the available page numbers, it was not possible to publish all the posters that were presented at the special poster session. We express our sincere thanks to all the participants in this session. 相似文献
13.
The propagation characteristics of shear horizontally polarized (SH) waves passing through (Ni42Nb28Zr30)100–x Hx (x = 0–15.2) glassy alloys were investigated as a function of hydrogen content. With an increase in hydrogen content, the propagation time and main frequency of the receiving waves show increase and decrease, respectively, indicating expan‐ sion in average atomic distance which comes from solution of hydrogen. In sharp contrast to crystalline alloys, the decrease in damping ratio and the delay in phase with increasing hydrogen suggest a strong settlement of hydrogen into four‐coordination sites surrounded tetrahedrally by four Zr atoms and the resulting increase in dynamic elasticity, respectively. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
X.P. Zhu Tomiyuki Yukawa Hisayuki Suematsu Kiyoshi Yatsui Y. Inoue 《Applied Surface Science》2006,252(16):5776-5782
X-ray photoelectron spectroscopy (XPS) is used to probe oxidation states of Si species in particles deposited using a pulsed ion-beam evaporation method. The effects of He ambient gas, ion beam intensity and post-treatments on the oxides composition and oxygen content have been studied. It is found that presence of He ambient gas led to a profound oxidation of Si species as compared to that prepared in vacuum at the same ion-beam ablation energy, i.e. both increase of SiO2 component and oxygen concentration in the oxides coverage. The deposition in He also resulted in an increase of oxygen concentration even under lower ablation intensity, but a higher Si suboxides concentration. It is revealed that the reaction between Si and O was controlled by the ion beam intensity (temperature of Si plasma) and the gas ambient (collision probability of Si and O species). The difference in structure of oxide layers for samples obtained under various conditions is discussed based on the results of XPS analyses. 相似文献
15.
16.
Tomohiro Kyotani Sonoko Kakui Takehito Mizuno Naoto Shimotsuma Soushi Inoue Junji Saito 《Analytical sciences》2006,22(7):1031-1034
A zeolite NaA (LTA) membrane supported by an alumina porous support tube for pervaporation (PV) dehydration of ethanol was characterized by transmission electron microscopy (TEM) using a focused ion beam (FIB) thin-layer specimen preparation technique and by Fourier transform infrared attenuated total reflectance method (FTIR-ATR) using a diamond prism as the waveguide. FIB-TEM clearly presented cross-section images up to about 15 microm depth from the membrane surface. FTIR-ATR monitored the Si-O asymmetric stretching vibration spectrum. The Si-O spectrum was compared with the TEM image and their relationships were discussed. By combining the two methods, we could study the thickness of surface LTA crystals, the grain boundary, the LTA/alumina interface structure and the crystallinity and density of materials inside of the alumina porous support. Consequently, fine structure changes of the LTA membrane corresponding to the hydrothermal synthesis condition could be sensitively detected. 相似文献
17.
18.
S. Sasa A. Nakashima Y. Nakajima M. Inoue 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):224
We fabricated nanoscale open-dot structures in an InAs surface inversion layer using an atomic-force-microscope oxidation process. Due to its superior nanofabrication capability, small open-dot structures with the feature size ranging between 100 and 300 nm were successfully fabricated. The magnetoresistance signal measured at 4.2 K showed reproducible fluctuations and a periodic oscillation component that varies in both amplitude and periodicity depending on the dot size. We show that the period of the oscillations corresponds to that of the Aharonov–Bohm effect and propose that the possible mechanism for the oscillations is due to the formation of a one-dimensional electron channel enclosing the open-dot structure as a result of the electron transfer from the InAs oxide to InAs. 相似文献
19.
Hiroshi Sugimoto Hiromitsu Ohshima Shohei Inoue 《Journal of polymer science. Part A, Polymer chemistry》2003,41(22):3549-3555
The first successful example of the formation of polycarbonate from 1-atm carbon dioxide and epoxide was demonstrated by the alternating copolymerization of carbon dioxide and epoxide with manganese porphyrin as a catalyst. The copolymerization of carbon dioxide and cyclohexene oxide with (porphinato)manganese acetate proceeded under the 1-atm pressure of carbon dioxide to give a copolymer with an alternating sequence. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3549–3555, 2003 相似文献
20.
Kojima T. Inoue E. Tsuchiya M. Ishimaru K. 《Journal of Thermal Analysis and Calorimetry》2003,72(2):737-742
TG, swelling, and viscometric studies are presented for the residues, PTHF/IPDI polymer networks, and the extracts, the linear
polymers and unreacted IPDI, after Soxhlet extraction of PTHF/IPDI reaction products. The products are obtained by reacting
PTHF with 650, 1400, (2×650+1×2900), or 2900 of molecular mass with IPDI at various concentrations in bulk. The results on
the swelling and the viscosity experiments suggest that the PTHF/IPDI reaction products have a usual expectable structure.
All the TG curves are a double stage curve. The initial stage and the last stage seem to reflect decomposition of PTHF chains
and vaporization of the remainder, IPDI, respectively. These are analyzed by a trial-and-error construction, supposing double
event behavior. The values of ratio of mass loss associated with the initial event, W01, to the mass loss associated with the last event, W02, are smaller than the expectable those. This suggests that Event 2 involves vaporization of the decomposition products of
PTHF moieties bonded to IPDI in addition to vaporization of IPDI.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献