全文获取类型
收费全文 | 4466篇 |
免费 | 162篇 |
国内免费 | 18篇 |
专业分类
化学 | 3049篇 |
晶体学 | 45篇 |
力学 | 104篇 |
数学 | 411篇 |
物理学 | 1037篇 |
出版年
2023年 | 23篇 |
2022年 | 74篇 |
2021年 | 101篇 |
2020年 | 82篇 |
2019年 | 76篇 |
2018年 | 66篇 |
2017年 | 52篇 |
2016年 | 138篇 |
2015年 | 127篇 |
2014年 | 153篇 |
2013年 | 251篇 |
2012年 | 345篇 |
2011年 | 373篇 |
2010年 | 199篇 |
2009年 | 195篇 |
2008年 | 285篇 |
2007年 | 262篇 |
2006年 | 239篇 |
2005年 | 228篇 |
2004年 | 175篇 |
2003年 | 163篇 |
2002年 | 149篇 |
2001年 | 100篇 |
2000年 | 94篇 |
1999年 | 78篇 |
1998年 | 63篇 |
1997年 | 41篇 |
1996年 | 53篇 |
1995年 | 48篇 |
1994年 | 48篇 |
1993年 | 47篇 |
1992年 | 32篇 |
1991年 | 22篇 |
1990年 | 31篇 |
1989年 | 22篇 |
1987年 | 9篇 |
1986年 | 17篇 |
1985年 | 19篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1980年 | 11篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1974年 | 7篇 |
1973年 | 10篇 |
1943年 | 8篇 |
1942年 | 13篇 |
1941年 | 10篇 |
排序方式: 共有4646条查询结果,搜索用时 15 毫秒
61.
Jung-Kyu Park Ji-Wook Yoon Kyung-Hyun Whang Sung-Hak Cho 《Applied Physics A: Materials Science & Processing》2012,108(2):269-274
The effective removal of nanoparticles from a silicon wafer surface was demonstrated using the self-channeled plasma filament excited by a femtosecond (130?fs) Ti:sapphire laser (?? p=790?nm). The photoinduced self-channeled plasma filament in air reached a length of approximately 110?C130?mm from the first focal spot with diameters ranging from 40 to 50???m at input intensities of more than 1.0×1014?W/cm2. By the scan of wafer using the X?CY?CZ stage during self-channeled plasma filament, the removal variation of nanoparticles on surface was observed in situ before and after the plasma filament occurred. The cleaning efficiency was strongly dependent on the gap distance between the plasma filament and the surface. The removal efficiency of nanoparticles reached 96?% with no damage to the surface when the gap was 150???m. 相似文献
62.
Aliu E Andringa S Aoki S Argyriades J Asakura K Ashie R Berns H Bhang H Blondel A Borghi S Bouchez J Burguet-Castell J Casper D Cavata C Cervera A Cho KO Choi JH Dore U Espinal X Fechner M Fernandez E Fukuda Y Gomez-Cadenas J Gran R Hara T Hasegawa M Hasegawa T Hayashi K Hayato Y Helmer RL Hill J Hiraide K Hosaka J Ichikawa AK Iinuma M Ikeda A Inagaki T Ishida T Ishihara K Ishii T Ishitsuka M Itow Y Iwashita T Jang HI Jeon EJ Jeong IS Joo K Jover G Jung CK Kajita T Kameda J Kaneyuki K Kato I 《Physical review letters》2005,94(8):081802
We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma). 相似文献
63.
M.C. Robinson D.J. Morris P.D. Hayenga J.H. Cho C.D. Richards R.F. Richards D.F. Bahr 《Applied Physics A: Materials Science & Processing》2006,85(2):135-140
Piezoelectric membranes have been fabricated that incorporate a gold bottom electrode with an adhesion layer of titanium–tungsten (10:90 wt. %). For solution-deposited acetic acid based lead zirconate titanate (HoAc-PZT) with a Zr:Ti ratio of 40:60, the film’s average piezoelectric coefficient, e31, is -5.31 C/m2, with a dielectric constant of 814 at 200 Hz, which is similar to values for platinum bottom electrodes. The PZT structure remains columnar on both types of bottom electrodes. Initial fabrication attempts resulted in cracking that initiated in the PZT layer of the structure. X-ray photoelectron spectroscopy was utilized to establish how processing affects diffusion throughout the composite membrane structure. Crack-free membranes were fabricated and tested. This paper discusses the performance properties and piezoelectric fatigue results for these membranes. PACS 77.84.-s; 77.84.Lf 相似文献
64.
Sug-Bong Choe Yoon-Chul Cho Hyuk-Jae Jang Sung-Chul Shin 《Journal of magnetism and magnetic materials》2002,240(1-3):308-310
Activation volumes of the wall-motion and nucleation processes in Co-based multilayer films were characterized from time-resolved domain evolution patterns. These activation volumes were both sensitive to the multilayer structure as well as the film preparation condition. The two activation volumes were generally unequal with each other and the inequality directly influenced on magnetization reversal behavior. 相似文献
65.
Dae-Hyung Cho Yong-Duck Chung Kyu-Seok Lee Kyung-Hyun Kim Ju-Hee Kim Soo-Jeong Park Jeha Kim 《Current Applied Physics》2013,13(9):2033-2037
We report the effect of Cr impurity barrier on Cu(In,Ga)Se2 (CIGS) thin-film solar cells prepared on flexible substrates. The Cr films with varying the thickness (tCr) were deposited on stainless steel substrates using direct-current magnetron sputtering. The solar cell performance was improved by increasing tCr since the diffusion of Fe impurities from the substrate to CIGS was suppressed. Although the elemental composition, grain size, and strain of CIGS film showed little change with varying Fe content, the fill factor and the short-circuit current density increased as decreasing Fe. The Fe increased the series resistance, shunt paths, and saturation current density. The reduction of Fe caused a steeper bandgap grading in CIGS which enhances current collection due to higher electric fields in bulk CIGS. CIGS solar cells with 1000 nm-thick Cr barrier showed the best conversion efficiency of 9.05%. 相似文献
66.
Ikechi Augustine Ukaegbu M. Rakib Uddin Jamshid Sangirov Nga T. H. Nguyen Tae-Woo Lee Mu Hee Cho Hyo-Hoon Park 《Optical and Quantum Electronics》2017,49(7):243
This work presents a full-duplex and multifunction bidirectional transceiver for optical interconnect application. The transceiver utilizes a common limiting amplifier/gain stage, thus reducing total chip area and total power consumption. While providing a full-duplex bidirectional transmission with the aid of a hybrid circuit between the electrical input/output (I/O) and the optoelectronic signals from the transmitter and receiver circuits, it also allows for a half-duplex operation with the aid of a switch between the transimpedance amplifier signals and the transmitter electrical input from the I/O port. The multifunction bidirectional CMOS transceiver is designed in a 0.13 µm Si-CMOS technology, with power dissipation of 79 and 54.4 mW for the transmitter and receiver, respectively. It shows a 3-dB bandwidth of 5.58 and 5.69 GHz for the transmitter and the receiver respectively and with a 3-dB gain of 66.14 and 69.6 dB, in full-duplex mode. The transceiver operates up to 7 Gb/s in full-duplex mode. 相似文献
67.
Balest R Cho K Daoudi M Ford WT Johnson DR Lingel K Lohner M Rankin P Smith JG Alexander JP Bebek C Berkelman K Bloom K Browder TE Cassel DG Cho HA Coffman DM Drell PS Ehrlich R Gaiderev P Garcia-Sciveres M Geiser B Gittelman B Gray SW Hartill DL Heltsley BK Jones CD Jones SL Kandaswamy J Katayama N Kim PC Kreinick DL Ludwig GS Masui J Mevissen J Mistry NB Ng CR Nordberg E Patterson JR Peterson D Riley D Salman S Sapper M Würthwein F Avery P Freyberger A Rodriguez J Stephens R Yang S Yelton J 《Physical review letters》1994,72(15):2328-2331
68.
Acosta D Athanas M Masek G Paar H Bean A Gronberg J Kutschke R Menary S Morrison RJ Nakanishi S Nelson HN Nelson TK Richman JD Ryd A Tajima H Schmidt D Sperka D Witherell MS Procario M Yang S Balest R Cho K Daoudi M Ford WT Johnson DR Lingel K Lohner M Rankin P Smith JG Alexander JP Bebek C Berkelman K Besson D Browder TE Cassel DG Cho HA Coffman DM Drell PS Ehrlich R Galik RS Garcia-Sciveres M Geiser B Gittelman B Gray SW Hartill DL Heltsley BK Jones CD Jones SL Kandaswamy J Katayama N Kim PC 《Physical review D: Particles and fields》1994,49(11):5690-5700
69.
Anisha Gokarna Yong Hwan Kim Yong-Hoon Cho Min Su Lee In Cheol Kang Hyun Kyu Park Min Gon Kim Bong Hyun Chung 《Optical Review》2006,13(4):288-291
We demonstrate the fluorescence mapping of protein microarrays by the technique of scanning near-field optical microscopy
(SNOM) and confocal microscopy. Micron sized spots (300 μm) of human Immunoglobulin G (hIgG) protein with and without a Cy3
dye labeling have been fabricated on glass substrates by an immobilization method which makes use of calixcrown derivatives
termed Prolinker. We have also tried to probe into the well-known “doughnut effect” observed in fluorescence images of proteins
using the SNOM technique. The topographic and fluorescence SNOM images revealed that the number of proteins at the boundary
of the spot were more than at the center in the case of the microarray spot which showed brighter luminescence at the edge
than at the center in the confocal image. 相似文献
70.
Jung Tae ParkJoo Hwan Koh Jin Ah SeoYong Soo Cho Jong Hak Kim 《Applied Surface Science》2011,257(20):8301-8306
We report on the novel ternary hybrid materials consisting of semiconductor (TiO2), metal (Ag) and polymer (poly(oxyethylene methacrylate) (POEM)). First, a hydrophilic polymer, i.e. POEM, was grafted from TiO2 nanoparticles via the surface-initiated atom transfer radical polymerization (ATRP) technique. These TiO2-POEM brush nanoparticles were used to template the formation of Ag nanoparticles by introduction of a AgCF3SO3 precursor and a NaBH4 aqueous solution for reduction process. Successful grafting of polymeric chains from the surface of TiO2 nanoparticles and the in situ formation of Ag nanoparticles within the polymeric chains were confirmed using transmission electron microscopy (TEM), UV-vis spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). FT-IR spectroscopy also revealed the specific interaction of Ag nanoparticles with the CO groups of POEM brushes. This study presents a simple route for the in situ synthesis of both metal and polymer confined within the semiconductor, producing ternary hybrid inorganic-organic nanomaterials. 相似文献