全文获取类型
收费全文 | 5833篇 |
免费 | 187篇 |
国内免费 | 8篇 |
专业分类
化学 | 4381篇 |
晶体学 | 69篇 |
力学 | 58篇 |
综合类 | 2篇 |
数学 | 235篇 |
物理学 | 1283篇 |
出版年
2023年 | 37篇 |
2021年 | 61篇 |
2020年 | 82篇 |
2019年 | 91篇 |
2018年 | 71篇 |
2017年 | 39篇 |
2016年 | 112篇 |
2015年 | 122篇 |
2014年 | 116篇 |
2013年 | 293篇 |
2012年 | 280篇 |
2011年 | 315篇 |
2010年 | 180篇 |
2009年 | 197篇 |
2008年 | 316篇 |
2007年 | 357篇 |
2006年 | 318篇 |
2005年 | 369篇 |
2004年 | 278篇 |
2003年 | 229篇 |
2002年 | 236篇 |
2001年 | 133篇 |
2000年 | 128篇 |
1999年 | 80篇 |
1998年 | 74篇 |
1997年 | 48篇 |
1996年 | 89篇 |
1995年 | 56篇 |
1994年 | 52篇 |
1993年 | 69篇 |
1992年 | 67篇 |
1991年 | 68篇 |
1990年 | 53篇 |
1989年 | 59篇 |
1988年 | 54篇 |
1987年 | 55篇 |
1986年 | 52篇 |
1985年 | 92篇 |
1984年 | 77篇 |
1983年 | 41篇 |
1982年 | 66篇 |
1981年 | 52篇 |
1980年 | 67篇 |
1979年 | 58篇 |
1978年 | 56篇 |
1977年 | 40篇 |
1976年 | 42篇 |
1975年 | 28篇 |
1974年 | 33篇 |
1973年 | 27篇 |
排序方式: 共有6028条查询结果,搜索用时 15 毫秒
11.
The double-bond conversion of UV-cured resins prepared from pentaerythritol triacrylate (PETA) was determined by pyrolysis-gas chromatography in the presence of an organic alkali, tetramethylammonium hydroxide (TMAH). The pyrogram of the uncured prepolymer compound, consisting of PETA and a photoinitiator, 2,2-dimethoxy-2-phenylacetophenone, contained specific products reflecting the original acrylate structure, such as methyl acrylate (MA) and methyl ethers of pentaerithritol. Meanwhile, in pyrograms of the UV-cured PETA, the yields of MA considerably decreased. The double-bond conversions of the cured resins, irradiated with various UV dosages, were calculated based on the relative yields of MA among specific products in the pyrograms. The conversions determined by this approach were analyzed by comparing them with those estimated by Fourier-transform infrared spectroscopy. 相似文献
12.
13.
T. Kasahara H.S. Park D. Shindo H. Yoshikawa T. Sato K. Kondo 《Journal of magnetism and magnetic materials》2006
Domain wall motion in Mn–Zn and Ni–Zn ferrites with applied magnetic fields is investigated by in situ observations with Lorentz microscopy and electron holography. It is found that both Mn–Zn and Ni–Zn ferrites have a mean grain size of approximately 10 μm and several pores with sizes ranging from 0.2 to 1.1 μm. In situ observations by Lorentz microscopy with an applied magnetic field reveals that in Mn–Zn ferrite, the domain walls move easily across the grain boundary, while in Ni–Zn ferrite, the domain walls move along the grain boundary but are pinned at the grain boundary and pores. From in situ observations of Ni–Zn ferrite by electron holography, it is clarified that domain wall pinning at the grain boundary retards a sensitive increase in magnetic flux parallel to the applied field direction, which is considered to result in high hysteresis loss. 相似文献
14.
Curved Ferroelectric Liquid Crystal Matrix Displays Driven by Field-Sequential-Color and Active-Matrix Techniques 总被引:1,自引:0,他引:1
Hideo Fujikake Hiroto Sato Takeshi Murashige Yoshihide Fujisaki Taiichiro Kurita Tadahiro Furukawa Fumio Sato 《Optical Review》2006,13(1):14-19
This paper describes a curved field-sequential-color matrix display using fast-response ferroelectric liquid crystal. Black
matrix and transparent electrode patterns were formed on a thin plastic substrate by a transfer method from a glass substrate.
While a composite film of liquid crystal and micro-polymers of walls and fibers was formed between the flexible substrates
by printing, laminating and curing processes of a solution of monomers and liquid crystal, the mechanical stability was enhanced
by use of multi-functional monomers to form large display panels. The image pixels of the matrix panel were driven by an active
matrix scheme using an external switch transistor array at a frequency of 180 Hz for intermittent three-primary-color backlight
illumination. The flexible A4-paper-sized color display with 24 × 16 pixels and 60 Hz field frequency was demonstrated by
illuminating it with sequential three-primary-color lights from light-emitting diodes of the backlight. Our display system
is useful in various information displays because of its freedom of setting and location. 相似文献
15.
This paper reports a successful achievement of laser-induced biological cell fusion using an excimer laser excited dye laser. To our knowledge, we examined for the first time the dependence of fusion rate on laser pulse energy, number of laser pulses, and laser wavelength. Maximum fusion rate of approximately 50% was obtained by this laser fusion technology. 相似文献
16.
T. Sato 《Journal of Radioanalytical and Nuclear Chemistry》1991,152(1):219-225
Distribution coefficients of fission products on a cation exchanger in 1M nitirc acid were measured as a function of the pressure by means of the column method. The distribution coefficients were found to decrease with the pressure, and this became more pronounced with increasing charge of the ions. The distribution coefficients of yttrium and RuNO3+ decreased with the pressure to a relatively greter extent than lighter lanthanides, and RuNO3+ appeared at a separate peak from europium in the elution chromatogram as the pressure was increased up to 900 kg/cm2. 相似文献
17.
Selective oxidation of an AlInAs layer was investigated for enhancement of magneto-optic effect in an optical isolator. Twelve times nonreciprocal phase shift enhancement was estimated from a measured AlInAs-oxide refractive index. 相似文献
18.
Hiroyasu Sato 《应用有机金属化学》1991,5(4):207-219
This is meant to be a brief overview of the developments of research activities in Japan on organometallic compounds related to their use in electronic and optoelectronic devices. The importance of organometallic compounds in the deposition of metal and semiconductor films for the fabrication of many electronic and opto-electronic devices cannot be exaggerated. Their scope has now extended to thin-film electronic ceramics and high-temperature oxide superconductors. A variety of organometallic compounds have been used as source materials in many types of processing procedures, such as metal–organic chemical vapor deposition (MOCVD), metalorganic vapor-phase epitaxy (MOVPE), metal–organic molecular-beam epitaxy (MOMBE), etc. Deposited materials include silicon, Group III–V and II–VI compound semiconductors, metals, superconducting oxides and other inorganic materials. Organometallic compounds are utilized as such in many electronic and optoelectronic devices; examples are conducting and semiconducting materials, photovoltaic, photochromic, electrochromic and nonlinear optical materials. This review consists of two parts: (I) research related to the fabrication of semiconductor, metal and inorganic materials; and (II) research related to the direct use of organometallic materials and basic fundamental research. 相似文献
19.
20.
M. Sato 《Journal of mathematical chemistry》1991,7(1):341-352
In the first part, a topological characterization of various zeolite frameworks is performed on the basis of the Hamiltonian graph. It affords a simple representation of the framework connectivity, and presents some possibility of the classification as well as the prediction of unknown frameworks. In the second part, a simple and direct method based on the connectivity matrix is presented, by which all the possible Al distributions in a given framework are derived exhaustively under the restriction of Loewenstein's rule. An example of Al preference site determination is applied for zeolite ZSM-5 and compared with the result by the SCF-MO method. 相似文献