全文获取类型
收费全文 | 2505篇 |
免费 | 114篇 |
国内免费 | 9篇 |
专业分类
化学 | 2097篇 |
晶体学 | 19篇 |
力学 | 29篇 |
数学 | 81篇 |
物理学 | 402篇 |
出版年
2022年 | 12篇 |
2021年 | 25篇 |
2020年 | 37篇 |
2019年 | 47篇 |
2018年 | 32篇 |
2017年 | 25篇 |
2016年 | 66篇 |
2015年 | 58篇 |
2014年 | 62篇 |
2013年 | 99篇 |
2012年 | 128篇 |
2011年 | 184篇 |
2010年 | 79篇 |
2009年 | 93篇 |
2008年 | 183篇 |
2007年 | 165篇 |
2006年 | 169篇 |
2005年 | 139篇 |
2004年 | 133篇 |
2003年 | 108篇 |
2002年 | 93篇 |
2001年 | 24篇 |
2000年 | 33篇 |
1999年 | 35篇 |
1998年 | 27篇 |
1997年 | 28篇 |
1996年 | 31篇 |
1995年 | 16篇 |
1994年 | 23篇 |
1993年 | 21篇 |
1992年 | 15篇 |
1991年 | 14篇 |
1990年 | 20篇 |
1989年 | 21篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 11篇 |
1985年 | 27篇 |
1984年 | 44篇 |
1983年 | 17篇 |
1982年 | 35篇 |
1981年 | 29篇 |
1980年 | 16篇 |
1979年 | 22篇 |
1978年 | 22篇 |
1977年 | 14篇 |
1976年 | 15篇 |
1975年 | 17篇 |
1974年 | 16篇 |
1973年 | 30篇 |
排序方式: 共有2628条查询结果,搜索用时 15 毫秒
11.
Abstract— Irradiation of near-UV light in the presence of FeCl3 caused oxidation of adenosine with concomitant reduction of Fe(III) under either aerobic or anaerobic atmosphere. Major photoproducts were adenine and adenosine-5'-aldehyde, showing that oxidation took place mostly at the ribose moiety of adenosine. Detailed study showed that the reaction proceeded by the light absorption due to Fe(III) at 300-350 nm. 相似文献
12.
A simple and rapid method for the analysis of trace amounts of gold(III), palladium(II), and platinum(IV) by the combined use of graphite furnace atomic absorption spectrometry and anion-exchange separation was proposed, and successfully applied to the rapid determination of metals in industrial waste solutions obtained from the final process of noble-metal recovery factories, because noble metals can be selectively and quantitatively separated to a high degree by using a small column containing only a 0.7 g-portion of a common anion-exchange resin and a dilute thiourea solution. 相似文献
13.
Copper(II) is determined by non-extractive spectrophotometry as a complex of butylene dithiocarbamate formed in situ by reaction between carbon disulfide and pyrrolidine in aqueous Triton X-100 medium. This method is similar to that with butylene dithiocarbamate as starting material in the sense of simplicity, sensitivity, precision and accuracy. Pyrrolidine is the best of seven secondary amines tested in this way for copper determinations. 相似文献
14.
Takeshi Kitatani Masahiko Kondow Koji Nakahara M. C. Larson Kazuhisa Uomi 《Optical Review》1998,5(2):69-71
Temperature stability of the threshold current and the lasing wavelength is investigated in a 1.3-μm GaInNAs/ GaAs single quantum-well laser. The measured characteristic-temperature was 88 K. The small wavelength shift per change in temperature of 0.35 nm/°C was obtained, indicating the superior lasing-wavelength stability. Therefore, it is shown experimentally that GaInNAs is very promising material for the fabrication of light source with excellent high-temperature performance for optical fiber communications. 相似文献
15.
Takahiro Gunji Ryosuke Shimano Koji Arimitsu Yoshimoto Abe 《Journal of polymer science. Part A, Polymer chemistry》2006,44(8):2542-2550
Tetraethoxysilane (TEOS) and polyethoxysiloxanes (PEOSs; prepared by the acid‐catalyzed hydrolytic polycondensation of TEOS) were subjected to the sol–gel process in the presence of cetyltrimethylammonium bromide (CTAB), respectively. The PEOSs with Mw 700–26,000, as prepared by sol–gel coating of TEOS and PEOS under various conditions, were used. Uniform and crack‐free thin films of thickness 276–613 nm were prepared by spin‐coating of a PEOS solution containing CTAB. When the coating films were sintered at 400 °C, the combustion of ethoxy groups and CTAB took place to provide porous silica thin films. The structure of the thin films was found to be dependent on the molecular weight of PEOS and the molar ratio of CTAB/Si: lamellar or hexagonal phase was observed for Mw less than 15,000 and for CTAB/Si molar ratios greater than 0.10. Honeycomb structures were observed for Mw less than 5000 and for CTAB/Si molar ratios of 0.15. The honeycomb structure was also observed by atomic force microscopy and transmission electron microscope. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2542–2550, 2006 相似文献
16.
17.
18.
Stuart D Breedon RE Kim GN Ko W Lander RL Maeshima K Malchow RL Smith JR Imlay R Kirk P Lim J McNeil RR Metcalf W Myung SS Cheng CP Gu P Li J Li YK Ye MH Zhu YC Abashian A Gotow K Hu KP Low EH Mattson ME Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Frautschi M Kagan H Kass R Trahern CG Abe K Fujii Y Higashi Y Kim SK Kurihara Y Maki A Nozaki T Omori T Sagawa H Sakai Y Sugimoto Y Takaiwa Y Terada S Walker R Kajino F Perticone D Poling R Thomas T Ishi Y Miyano K Miyata H Sasaki T 《Physical review letters》1990,64(9):983-986
19.
Kumita T Sagawa H Auchincloss P Blanis D Bodek A Budd H Eno S Fry CA Harada H Ho YH Kim YK Mori T Olsen SL Shaw NM Sill A Thorndike EH Ueno K Zheng HW Abe K Fujii Y Higashi Y Kim SK Kurihara Y Maki A Nozaki T Omori T Sakai Y Sugimoto Y Takaiwa Y Terada S Walker R Imlay R Kirk P Lim J McNeil RR Metcalf W Myung SS Cheng CP Gu P Li J Li YK Ye MH Zhu YC Abashian A Gotow K Hu KP Low EH Mattson ME Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Frautschi M Kagan H Kass R Trahern CG 《Physical review D: Particles and fields》1990,42(5):1339-1349
20.
Kim GN Kim EJ Son D Bacala A Imlay R Kirk P McNeil RR Metcalf W Cheng CP Mao ZP Yan Y Xu YT Zhu YC Abashian A Gotow K Kajino F Low E Naito F Piilonen L Childers R Darden C Lusin S Rosenfeld C Wilson S Frautschi M Kagan H Kass R Trahern CG Ko W Lander RL Maeshima K Malchow RL Higashi JR Kurihara Y Maki A Nozaki T Omori T Perez P Sagawa H Sakai Y Sugimoto Y Takaiwa Y Terada S Tsuchiya K Poling R Green J Park IH Sakamoto S Sannes F Schnetzer S Stone R Trentalange S Zimmerman D Miyano K Miyata H 《Physical review letters》1988,61(8):911-914