全文获取类型
收费全文 | 1382篇 |
免费 | 17篇 |
国内免费 | 5篇 |
专业分类
化学 | 996篇 |
晶体学 | 27篇 |
力学 | 14篇 |
数学 | 49篇 |
物理学 | 318篇 |
出版年
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 4篇 |
2016年 | 17篇 |
2015年 | 21篇 |
2014年 | 27篇 |
2013年 | 50篇 |
2012年 | 54篇 |
2011年 | 77篇 |
2010年 | 53篇 |
2009年 | 49篇 |
2008年 | 64篇 |
2007年 | 66篇 |
2006年 | 77篇 |
2005年 | 86篇 |
2004年 | 75篇 |
2003年 | 71篇 |
2002年 | 57篇 |
2001年 | 36篇 |
2000年 | 22篇 |
1999年 | 25篇 |
1998年 | 9篇 |
1997年 | 18篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 22篇 |
1991年 | 29篇 |
1990年 | 18篇 |
1989年 | 19篇 |
1988年 | 10篇 |
1987年 | 18篇 |
1986年 | 15篇 |
1985年 | 17篇 |
1984年 | 25篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 15篇 |
1980年 | 24篇 |
1979年 | 17篇 |
1978年 | 18篇 |
1977年 | 20篇 |
1976年 | 8篇 |
1975年 | 12篇 |
1974年 | 11篇 |
1973年 | 13篇 |
排序方式: 共有1404条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
15.
Measurement Accuracy in Phase-Shifting Point Diffraction Interferometer with Two Optical Fibers 总被引:1,自引:0,他引:1
Toshiaki Matsuura Satoru Okagaki Takaaki Nakamura Yasushi Oshikane Haruyuki Inoue Motohiro Nakano Toshihiko Kataoka 《Optical Review》2007,14(6):401-405
A phase-shifting point diffraction interferometer (PS/PDI) with point sources of two single mode optical fibers has been developed,
which will be appropriate for the surface figure measurement of large aperture optics on a sub-nanometer scale. To reduce
the measurement error factors, a fiber optic plate (FOP) is used as a projection plane for interference pattern. Errors caused
by imperfection of optical alignment, such as position of point sources and tilt of FOP, are minimized by analyzing the measured
phase data with an original method. Measurement accuracy in the PS/ PDI is estimated with the interference pattern produced
by the two optical fiber sources. If inhomogeneity of the FOP and a systematic error of the PS/PDI are eliminated, the measurement
accuracy of the present system is estimated to be less than 4nm P-V and 0.7nm rms, respectively, at a measurement wavelength
of 632.8 nm. 相似文献
16.
We fabricated high-quality InAlN/GaN heterostructures by metal–organic vapor phase epitaxy (MOVPE). X-ray diffraction measurements revealed that InAlN/GaN heterostructures grown under optimal conditions have flat surfaces and abrupt heterointerfaces. Electron mobility from 1200 to 2000 cm2/V s was obtained at room temperature. To our knowledge, this mobility is the highest ever reported for InAlN/GaN heterostructures. We also investigated the relationship between the Al composition and sheet electron density (Ns) for the first time. Ns increased from 1.0×1012 to 2.7×1013 cm−2 when the Al composition increased from 0.78 to 0.89. 相似文献
17.
Hoon Kim Toshihiko Koseki Tomohiro Ohta Hiroshi Sato Yukihiro Shimogaki 《Applied Surface Science》2006,252(11):3938-3942
The adhesion of Cu on Ru substrates with different crystal orientations was evaluated. The crystal orientation of sputter deposited Ru could be changed from (1 0 0) to (0 0 1) by annealing at 650 °C for 20 min. The adhesion of Cu was evaluated by the degree of Cu agglomeration on Ru. Cu films on annealed Ru films with the (0 0 1) crystal orientation showed 28% lower RMS values and 50% lower Ru surface coverage than Cu as-deposited on Ru having the (1 0 0) crystal orientation after annealing at 550 °C for 30 min, which suggest that Cu wettability on the Ru(0 0 1) was better than that on the Ru(1 0 0) plane. The low lattice misfit of 4% between Cu(1 1 1) and Ru(0 0 1) may be the reason for this good adhesion property. 相似文献
18.
19.
Low-noise operation of a 9-GHz hybridly mode-locked laser diode is demonstrated. The integrated timing jitter was 47 fs (10 Hz to 10 MHz) and 86 fs (10 Hz to 4.5 GHz), with a pulse width of 6.7 ps. The noise performance as a function of filter bandwidth and oscillator noise is also addressed. 相似文献
20.