全文获取类型
收费全文 | 705篇 |
免费 | 27篇 |
国内免费 | 2篇 |
专业分类
化学 | 551篇 |
晶体学 | 9篇 |
力学 | 4篇 |
数学 | 15篇 |
物理学 | 155篇 |
出版年
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 3篇 |
2016年 | 12篇 |
2015年 | 12篇 |
2014年 | 14篇 |
2013年 | 32篇 |
2012年 | 34篇 |
2011年 | 35篇 |
2010年 | 21篇 |
2009年 | 25篇 |
2008年 | 39篇 |
2007年 | 48篇 |
2006年 | 57篇 |
2005年 | 54篇 |
2004年 | 41篇 |
2003年 | 45篇 |
2002年 | 27篇 |
2001年 | 18篇 |
2000年 | 20篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 10篇 |
1994年 | 4篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1971年 | 3篇 |
1969年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有734条查询结果,搜索用时 15 毫秒
81.
Chie Hosokawa Yasutaka Sakamoto Suguru N. Kudoh Yoichiroh Hosokawa Takahisa Taguchi 《Applied Physics A: Materials Science & Processing》2013,110(3):607-612
We demonstrated the stimulation of neurons at a single-cell level in cultured neuronal network by a focused femtosecond laser. When the femtosecond laser was focused on a neuron loaded with a fluorescent calcium indicator, the fluorescence intensity immediately increased at the laser spot, suggesting that intracellular Ca2+ increases in the neuronal cell due to the femtosecond laser irradiation. The probability of Ca2+ elevation at the laser spot depended on the average laser power, irradiation time, and position of the focal point along the optical axis, indicating that the femtosecond laser activates neurons because of multiphoton absorption. Moreover, after laser irradiation of a single neuron cultured on multielectrode arrays, the evoked electrical activity of the neurons was demonstrated by electrophysiological systems, which concluded that the focused femtosecond laser could achieve stimulating a single neuron in a neuronal network with high spatial and temporal resolution. 相似文献
82.
Makoto Obata Yurie Tanaka Naoko Araki Shiho Hirohara Shigenobu Yano Kazunori Mitsuo Keisuke Asai Masafumi Harada Toyoji Kakuchi Chikara Ohtsuki 《Journal of polymer science. Part A, Polymer chemistry》2005,43(14):2997-3006
Pressure‐sensitive paint (PSP), which consists of luminescent molecules embedded in an oxygen‐permeable polymer, has been developed for use in wind‐tunnel experiments. To improve the PSP technique, a novel luminescent methacrylate monomer, 5‐[4‐(2‐methacryloyloxyethoxycarbonyl)phenyl]‐10,15,20‐triphenylporphinato platinum(II), was synthesized and copolymerized with isobutyl methacrylate and 2,2,2‐trifluoroethyl methacrylate to produce a dye‐pendant copolymer ( 2 ). The introduction of 5,10,15,20‐tetraphenylporphinato platinum(II) (PtTPP) dye into 2 was confirmed by ultraviolet–visible spectroscopy and extended X‐ray absorption fine structure measurements. The extent of PtTPP dye incorporation in 2 was proportional to the molar fraction of the PtTPP‐pendant methacrylate monomer in the feed. The oxygen‐sensing property of 2 was compared with that of a PSP consisting of PtTPP dye embedded in poly(isobutyl‐co‐2,2,2‐trifluoroethyl methacrylate). Although the simple mixture of PtTPP and poly(isobutyl‐co‐2,2,2‐trifluoroethyl methacrylate) showed a marked deviation from a single Stern–Volmer relation, novel copolymer 2 gave a highly linear Stern–Volmer plot. This was unequivocal evidence of dye conjugation on the oxygen‐sensing polymer film. © 2005Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2997–3006, 2005 相似文献
83.
We have proposed a method to control the three-dimensional electric field in the focus of an optical microscope using two non-twisted liquid crystal spatial light modulators, and to detect the molecular orientation of a single molecule. The three-dimensional electric field is generated by focusing the beam with two dimensional spatial distribution of polarization. The possibility of detection of three-dimensional single molecular orientation was shown by numerical calculations. © 2005 The Optical Society of Japan 相似文献
84.
Acetyl 29-methyl-29-methylidene-D:C-friedoolean-8-en-3beta-o1 (2), derived from bryonolic acid (D:C-friedoolean-8-en-3beta-ol-29-oic acid) (1), was crystallographically analyzed. Rings A-E of 2 adopted chair, half-chair, half-chair, boat (with bow and stern at C-13 and C-16), boat (with bow and stem at C-19 and C-22) conformations, respectively. Good agreement was found between the structures from X-ray crystallography and that from MM2 calculations. 相似文献
85.
T. Araki J. Kubo E. A. Paschos 《The European Physical Journal C - Particles and Fields》2006,45(2):465-475
We consider leptogenesis in a minimal S3 extension of the standard model with an additional Z2 symmetry in the leptonic sector. It is found that the CP phase appearing in the mass matrix of the left-handed neutrinos is the same as that for the CP asymmetries responsible for leptogenesis. Because of the discrete S3 x Z2 flavor symmetries, the CP asymmetries are strongly suppressed. To obtain a realistic size of the baryon number asymmetry in the universe, we therefore
have to assume that resonant enhancement of the CP asymmetries takes place, and that three degenerate right-handed neutrino masses of O(10) TeV are present.
Arrival of the final proofs: 22 November 2005
PACS:
11.30.Hv, 12.15.Ff, 14.60.Pq 相似文献
86.
Shuko Yokoyama Toshiyuki Yokoyama Tsutomu Araki Takahisa Hayashi Norihito Suzuki 《Optical Review》1998,5(3):179-184
Frequency of a 532 nm emission line of a diode-laser-pumped Nd:YAG laser is stabilized by lock of the output line to the linear absorption line of iodine molecules. The stabilization method is very simple utilizing the frequency shift caused with an acousto-optic modulator. The laser frequency was stabilized at the zero-crossing point of the second-derivative of the dispersion curve. Instability obtained by the error signal is affected by the phase-characteristics of detectors, which results in 3*10-8. 相似文献
87.
Keisuke Yoshiki Hiroki Azuma Kazuhiko Yoshioka Mamoru Hashimoto Tsutomu Araki 《Optical Review》2005,12(5):415-419
We have investigated the fluorescence lifetime properties of 8 calcium ion probes, calcium-green-1, calcium green-2, calcium
green-5N, calcium orange, oregon green 488 BAPTA-6F, fluo-3, fluo-4, and fluo-5N. We found that the decay time of calcium
green-5N varied more sensitively with calcium concentration than calcium green-1 which was known to be a highly sensitive
probe. We have also found that the center of observable range of calcium concentration by fluorescence lifetime measurement
is lower than that by fluorescence intensity measurement. 相似文献
88.
T. Minamisono T. Ohtsubo Y. Nakayama T. Araki K. Mashitani K. Matsuda E. Takahashi M. Tanigaki Y. Someda M. Tanaka A. Kitagawa M. Fukuda K. Matsuta Y. Nojiri 《Hyperfine Interactions》1992,73(3-4):347-356
Hyperfine interactions of β-emitting17F implanted in single crystals of NaF and CaF2 were studied. The nuclear magnetic moment of theT
π=5/2+ state was determined with an improved precision to be |μ(17F;π=5/2+,T
1/2=64.5s|=4.72130±0.00025. nm. Isoscalar magnetic moments of the doubly closed shell ±1 nucleon nuclei around mass number 16
were derived and the effective nucleon mass in the nucleus was discussed. 相似文献
89.
90.
Boric acid was trimethylsilylated with Me3SiCl/(Me3Si)2O in the presence of 2-propanol. The resulting mixture was analysed by using a combi 相似文献