全文获取类型
收费全文 | 5553篇 |
免费 | 266篇 |
国内免费 | 22篇 |
专业分类
化学 | 4158篇 |
晶体学 | 57篇 |
力学 | 116篇 |
数学 | 248篇 |
物理学 | 1262篇 |
出版年
2023年 | 32篇 |
2022年 | 21篇 |
2021年 | 76篇 |
2020年 | 96篇 |
2019年 | 105篇 |
2018年 | 67篇 |
2017年 | 56篇 |
2016年 | 164篇 |
2015年 | 152篇 |
2014年 | 166篇 |
2013年 | 277篇 |
2012年 | 377篇 |
2011年 | 444篇 |
2010年 | 192篇 |
2009年 | 166篇 |
2008年 | 315篇 |
2007年 | 283篇 |
2006年 | 290篇 |
2005年 | 259篇 |
2004年 | 261篇 |
2003年 | 205篇 |
2002年 | 212篇 |
2001年 | 140篇 |
2000年 | 115篇 |
1999年 | 74篇 |
1998年 | 58篇 |
1997年 | 49篇 |
1996年 | 50篇 |
1995年 | 39篇 |
1994年 | 52篇 |
1993年 | 54篇 |
1992年 | 65篇 |
1991年 | 38篇 |
1990年 | 43篇 |
1989年 | 47篇 |
1988年 | 43篇 |
1987年 | 43篇 |
1986年 | 42篇 |
1985年 | 86篇 |
1984年 | 80篇 |
1983年 | 28篇 |
1982年 | 40篇 |
1981年 | 33篇 |
1980年 | 40篇 |
1979年 | 64篇 |
1978年 | 47篇 |
1977年 | 53篇 |
1976年 | 48篇 |
1975年 | 33篇 |
1974年 | 24篇 |
排序方式: 共有5841条查询结果,搜索用时 281 毫秒
21.
Midori Kobayashi Hitoshi Awoki Yoshimi Nakazaki Gisaku Nakamura 《Graphs and Combinatorics》1989,5(1):243-244
In this paper, a perfect one-factorization ofK
36 is given, which is factor-1-rotational. 相似文献
22.
Osamu Kobayashi 《Mathematische Zeitschrift》1989,200(2):273-277
Financial support from the FRD is gratefully acknowledged 相似文献
23.
Analysis of Spectral Reflectance Using Normalization Method from Endoscopic Spectroscopy System 总被引:2,自引:0,他引:2
Masao Sambongi Makoto Igarashi Takashi Obi Masahiro Yamaguchi Nagaaki Ohyama Masahiko Kobayashi Yasushi Sano Shigeaki Yoshida Kazuhiro Gono 《Optical Review》2002,9(6):238-243
Objective assessment of gastrointestinal mucosal color is extremely important in the endoscopic diagnosis of digestive tract disease. In this paper, we propose a method to clarify the spectral characteristics of gastric and colon cancer. A large number of spectral reflectance data of mucous membrane are measured by the endoscopic spectroscopy system (ESS) in the National Cancer Center Hospital East, Kashiwa, Japan and the Department of Internal Medicine, Self-Defense Force Center Hospital, Tokyo, Japan. We assume that early cancer appears primarily in the spectral data of short wavelength, because it is usually present in a superficial cell where short wavelength light is scattered more strongly than long wavelength light. To identify the features in the short wavelength components, the spectral reflectance was divided by the reflectance of a long wavelength. We investigated the possibility of distinguishing early cancer from normal spectral data through statistical analysis, employing the projection axis as the mean difference between them. Early cancer and normal spectral data were projected on the projection axis, and the Student’s T-test was applied to evaluate the mean of the distribution between these data. 相似文献
24.
Toshiyuki Kobayashi 《Mathematische Annalen》1989,285(2):249-263
Partially supported by Grant-in-Aid for Scientific Research (No. 63740074) 相似文献
25.
A compact high-resolution optical heterodyne interferometer combining a two-frequency light module and a minute optical system
is described. The light module, which generates two independent frequencies of light, is fabricated by proton exchange method
on LiNbO3 substrate. We report an experiment evaluating measurement accuracy using a micro-displacement measurement system which incorporates
this interferometer. Results of the experiment with a standard thickness sample show high thermal stability with maximum measurement
error of 1.8 nm at a temperature from 19°C to 33°C. The system was used to measure the hysteresis of a piezoelectric element
for displacements of several nm, thereby making it possible to analyze the system quantitatively in practice. 相似文献
26.
S. I. Pesotskii R. B. Lyubovskii W. Biberacher M. V. Kartsovnik V. I. Nizhankovskii N. D. Kushch H. Kobayashi A. Kobayashi 《Journal of Experimental and Theoretical Physics》2002,94(2):431-433
Behavior of the de Haas-van Alphen (dHvA) oscillations depending on the angle between the magnetic field direction and the perpendicular to conducting layers in the quasi-two-dimensional organic metal α-(BETS)2 KHg(SCN)4 was studied in detail. The angular dependence of the dHvA oscillation amplitude exhibits a series of minima (at ±43.2°, ±64.6°, and ±72.0°) related to the “zero spin” effect, through which it is possible to estimate the splitting factor. An analysis of this value suggests that many-body interactions in the compound studied are either absent or at least radically weakened. 相似文献
27.
28.
29.
30.
This paper presents a simple chaotic circuit consisting of two capacitors, one linear two-port VCCS and one time-state-controlled
impulsive switch. The impulsive switch causes rich chaotic and periodic behavior. The circuit dynamics can be simplified into
a one-dimensional return map that is piecewise linear and piecewise monotone. Using the return map, we clarify parameter conditions
for existence of chaotic and periodic attractors and coexistence state of attractors. 相似文献