全文获取类型
收费全文 | 1846篇 |
免费 | 56篇 |
国内免费 | 6篇 |
专业分类
化学 | 1499篇 |
晶体学 | 32篇 |
力学 | 27篇 |
数学 | 63篇 |
物理学 | 287篇 |
出版年
2022年 | 16篇 |
2021年 | 14篇 |
2020年 | 25篇 |
2019年 | 25篇 |
2018年 | 17篇 |
2016年 | 32篇 |
2015年 | 31篇 |
2014年 | 39篇 |
2013年 | 114篇 |
2012年 | 88篇 |
2011年 | 97篇 |
2010年 | 74篇 |
2009年 | 67篇 |
2008年 | 112篇 |
2007年 | 86篇 |
2006年 | 109篇 |
2005年 | 96篇 |
2004年 | 80篇 |
2003年 | 81篇 |
2002年 | 107篇 |
2001年 | 30篇 |
2000年 | 21篇 |
1999年 | 32篇 |
1998年 | 16篇 |
1997年 | 24篇 |
1996年 | 26篇 |
1995年 | 21篇 |
1994年 | 18篇 |
1993年 | 20篇 |
1992年 | 19篇 |
1991年 | 14篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 14篇 |
1985年 | 35篇 |
1984年 | 25篇 |
1983年 | 15篇 |
1982年 | 28篇 |
1981年 | 21篇 |
1980年 | 27篇 |
1979年 | 23篇 |
1978年 | 20篇 |
1977年 | 18篇 |
1976年 | 17篇 |
1975年 | 15篇 |
1974年 | 7篇 |
1973年 | 12篇 |
1972年 | 8篇 |
排序方式: 共有1908条查询结果,搜索用时 46 毫秒
991.
Koichi Matsuo Kenichi Sakai Yosuke Matsushima Takayuki Fukuyama Kunihiko Gekko 《Analytical sciences》2003,19(1):129-132
We constructed an assembled-type MgF2 cell that can function under a high vacuum (10(-4) Pa), and is capable of measuring the vacuum-ultraviolet circular dichroism (VUVCD) spectrum in a wavelength region down to 140 nm for aqueous solutions. Its path length can be adjusted by various spacers in the range from 1.3 to 50 microm. The temperature-control unit of the cell was also constructed with a Peltier thermoelectric element to keep the temperature of a sample within an accuracy of +/- 1 degrees C in the temperature range from -30 to 70 degrees C. The optical cell and the temperature-control unit were confirmed to have good performance by monitoring the VUVCD spectra of ammonium d-camphor-10-sulfonate and myoglobin aqueous solutions. This cell is available not only for VUVCD spectroscopy, but also for vacuum-ultraviolet absorption measurements. 相似文献
992.
993.
Alexandre Gloter Kazutomo Suenaga Hiromichi Kataura Ryosuke Fujii Takeshi Kodama Hiroyuki Nishikawa Isao Ikemoto Koichi Kikuchi Shinzo Suzuki Yohji Achiba Sumio Iijima 《Chemical physics letters》2004,390(4-6):462-466
Supramolecular assemblages made of single wall carbon nanotubes (SWNT) filled with fullerenes or metal doped fullerenes exhibit promising electronic structure variations at a nanometer scale. Nevertheless, the knowledge about the structural defects of these systems is still very limited. Here, we report structural evolutions under high-resolution electron microscopic observation at the sensitivity of a single atom detection for Ca@C82 molecules encapsulated within SWNT. 相似文献
994.
A compact smooth surface of revolution which contains at least two circles through each point is either a sphere or a surface obtained by revolving a circle around a suitable axis.Dedicated to Professor Tadashi Nagano on his 60th birthday 相似文献
995.
996.
Hiroaki Ueda Koichi KitazawaTakehiko Matsumoto Hidenori Takagi 《Solid State Communications》2003,125(2):83-87
Resistivity (ρ) measurements on Magnéli phases V7O13 and V8O15 were performed under high pressures up to 3.5GPa. We have achieved a pressure-induced transition from an antiferromagnetic metal to a paramagnetic metal (PM) at critical pressures Pc≈3.4 and 3.3 GPa for V7O13 and V8O15, respectively. The critical behavior of ρ(T) near Pc turned out to be quite unusual in that no noticeable precursor effect was observed. This strongly contrasts with the canonical quantum critical point behavior observed in chemically modified systems such as Ni(S,Se)2 and V2O3. We propose that the presence of two distinct Fermi surface segments is responsible for the observed unusual behaviors. 相似文献
997.
The pressure broadening, pressure shift coefficients, and absolute intensities have been obtained for theJ= 6 ← 5 and theJ= 5 ← 4 absorption lines of acetonitrile CH3CN at 110 and 92 GHz, respectively. The absorption line shapes have been directly recorded modulating the radiation beam by an optical chopper. In addition to the self-effects, the foreign-broadening coefficients have also been measured for N2, O2, and Ar. 相似文献
998.
The infrared spectra of CO in Kr and Xe matrices have been measured with an improved resolution. On the basis of the concentration and temperature dependence, fine structures in the CO stretching fundamental band have been assigned to the CO monomer and the dimer. The red shifts of the vibrational line position of CO observed in the Ar, Kr, and Xe matrix increase monotonically with this order. The splitting of the fine structure decreases with this order. 相似文献
999.
1000.
Miki A Katagi M Kamata T Zaitsu K Tatsuno M Nakanishi T Tsuchihashi H Takubo T Suzuki K 《Journal of mass spectrometry : JMS》2011,46(4):411-416
A new approach is described for imaging mass spectrometry (IMS) of methamphetamine (MA) incorporated into human hair using matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF) and MALDI-Fourier transform ion cyclotron resonance (FTICR). A longitudinal section of a lengthwise manually-cut single human hair shaft from a chronic MA user was directly analyzed by MALDI-TOF-IMS after deposited with α-Cyano-4-hydroxycinnamic acid matrix. A barcode-like image, which was most probably generated with repeated intakes of MA, was for the first time obtained by monitoring MA-specific product ion in the selected reaction monitoring mode. Laser beam scan lengthwise-cut hair shafts gave only poor mass spectra of MA, probably due to the loss of MA and/or the thermal denaturation of hair. The identity of MA detected in hair was further confirmed by MALDI-FTICR mass spectrometry. A combination with ultra-high resolution mass spectrometry by FTICR provided indisputable identification of MA. The MALDI-FTICR-IMS of another hair shaft from the same MA user also provided a barcode-like image by monitoring the protonated molecule of MA with ultra-high resolution. The two barcode-like images exhibited a close resemblance. Thus, MALDI-IMS can offer a new perspective: 'imaging hair analyses for drugs'. 相似文献