全文获取类型
收费全文 | 2010篇 |
免费 | 110篇 |
国内免费 | 12篇 |
专业分类
化学 | 1669篇 |
晶体学 | 17篇 |
力学 | 14篇 |
数学 | 64篇 |
物理学 | 368篇 |
出版年
2023年 | 13篇 |
2022年 | 17篇 |
2021年 | 21篇 |
2020年 | 28篇 |
2019年 | 37篇 |
2018年 | 23篇 |
2017年 | 16篇 |
2016年 | 62篇 |
2015年 | 43篇 |
2014年 | 72篇 |
2013年 | 96篇 |
2012年 | 149篇 |
2011年 | 134篇 |
2010年 | 55篇 |
2009年 | 74篇 |
2008年 | 132篇 |
2007年 | 119篇 |
2006年 | 138篇 |
2005年 | 130篇 |
2004年 | 90篇 |
2003年 | 90篇 |
2002年 | 74篇 |
2001年 | 29篇 |
2000年 | 28篇 |
1999年 | 19篇 |
1998年 | 15篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1993年 | 21篇 |
1992年 | 18篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 35篇 |
1984年 | 20篇 |
1983年 | 12篇 |
1982年 | 21篇 |
1981年 | 15篇 |
1980年 | 25篇 |
1979年 | 17篇 |
1978年 | 16篇 |
1977年 | 16篇 |
1976年 | 9篇 |
1974年 | 9篇 |
1973年 | 10篇 |
1972年 | 9篇 |
排序方式: 共有2132条查询结果,搜索用时 15 毫秒
11.
Takaaki Kakitsuka Shinji Matsuo Seok–Hwan Jeong Toru Segawa Hiroshi Okamoto Yoshihiro Kawaguchi Yasuhiro Kondo Yuzo Yoshikuni Hiroyuki Suzuki 《Optical and Quantum Electronics》2006,38(12-14):1053-1060
We theoretically investigated a digitally tunable laser with a chirped ladder filter and a ring resonator to obtain a wide wavelength tuning range covering the whole C- or L- band. The clear relation between the tuning range and laser structure, especially the ladder filter, is described analytically. The introduction of a chirped structure into a ladder filter is effective in achieving both wide tunability and a stable lasing mode. A numerical simulation based on multimode rate equations shows that a tuning range of over 40 nm and a mode suppression ratio over 40 dB can be achieved by introducing a chirped ladder filter. 相似文献
12.
Yasuhiro Iba Shin-ichi Sano 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(7):216-223
In this paper, we describe an Aptian (Early Cretaceous) larger foraminiferal species Orbitolina (Mesorbitolina) parva from the limestone olistoliths in the lower part of the Yezo Group in the Yubari–Ashibetsu area, central Hokkaido and from limestone pebbles in the lowermost part of the Yezo Group in the Nakagawa area, northern Hokkaido. This is the first report of this species from the circum-North Pacific regions. Based on its occurrences, the shallow-marine carbonates, re-deposited in the lower part of the Yezo Group, are precisely assigned in age to the Late Aptian. Comparison of the lower part of the Yezo Group in central and northern Hokkaido indicates differences of the Aptian–Albian depositional history between the two areas. This study reveals that after Late Aptian, Mesogean key taxa (typical Cretaceous Tethyan biota) demised in the Northwest Pacific. 相似文献
13.
Takayuki Yamanaka Hideki Fukano Ken Tsuzuki Munehisa Tamura Ryuzo Iga Matsuyuki Ogasawara Yasuhiro Kondo Tadashi Saitoh 《光学学报》2003,23(Z1)
A comprehensive analysis of multi-quantum-well electroabsorption modulators buried with semi-insulating (SI)-InP is presented. We quantitatively demonstrate that suppression of Zn diffusion into the burying and optical core layers plays a key role in high-speed and high-extinction operation. 相似文献
14.
Yasuhiro Ishida 《Tetrahedron letters》2004,45(51):9455-9459
A planar-chiral imidazolium salt with a tris(oxoethylene) bridge was synthesized, and its potential application as a room temperature ionic liquid with a molecular-recognition ability was demonstrated. 相似文献
15.
Yasuhiro Gotoh 《Journal d'Analyse Mathématique》1998,75(1):67-84
Extending results of Staples and Smith-Stegenga, we characterize measurable subsets of a given domainD ⊃R
n on which BMO(D) functions areL
p
integrable or exponentially integrable. In particular, we characterize uniform domains by the integrability of BMO functions.
We also remark on the boundedness of domains satisfying a certain integrability condition for the quasihyperbolic metric. 相似文献
16.
17.
18.
19.
20.