全文获取类型
收费全文 | 640篇 |
免费 | 7篇 |
国内免费 | 5篇 |
专业分类
化学 | 219篇 |
晶体学 | 16篇 |
力学 | 39篇 |
数学 | 139篇 |
物理学 | 239篇 |
出版年
2021年 | 6篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2014年 | 8篇 |
2013年 | 16篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 16篇 |
2007年 | 35篇 |
2006年 | 38篇 |
2005年 | 16篇 |
2004年 | 35篇 |
2003年 | 23篇 |
2002年 | 27篇 |
2001年 | 27篇 |
2000年 | 19篇 |
1999年 | 12篇 |
1998年 | 9篇 |
1997年 | 15篇 |
1996年 | 6篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 8篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 14篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1974年 | 12篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1964年 | 5篇 |
1921年 | 4篇 |
排序方式: 共有652条查询结果,搜索用时 15 毫秒
31.
André Adler 《Journal of Theoretical Probability》2002,15(4):939-949
Consider independent and identically distributed random variables {X,X
nj
, 1jn,n1} with density f(x)=px
–p–1
I(x1), where p>0. We show that there exist unusual generalized Laws of the Iterated Logarithm involving the larger order statistics from our array. 相似文献
32.
Nanomechanical devices based on DNA 总被引:3,自引:0,他引:3
33.
M.N. Namboodiri P. Gonthier H. Ho J.B. Natowitz R. Eggers L. Adler P. Kasiraj C. Cerruti A. Chevarier N. Chevarier A. Demeyer 《Nuclear Physics A》1981,367(2):313-332
The emission of H and He isotopes in the reactions of 120 MeV 20Ne with 27A1 has been studied using light particle-heavy ion coincidence measurements. The energy spectra and angular correlations of the light particles emitted in coincidence with products of agree well with the predictions of the statistical model applied to the decay of the compound nucleus 47V. Results on α-particle emission associated with deep inelastic reactions leading to carbon and oxygen products are also reported. 相似文献
34.
35.
Alan J. Adler 《Experimental Mechanics》1971,11(5):378-384
A line of miniature strain and temperature telemetry transmitters have been developed for measurements in areas where direct-wire connections are not possible. The units described are 8–16 cu cm in volume (0.5–1.0 cu in.) and operate over a 0°C to 150°C ambient-temperature range with up to 30,000g′s acceleration. Battery life with a battery about the same size as the transmitter ranges from 50 to 200 hr. There is no degradation in accuracy for a 25-percent variation in battery voltage. Two types of strain transmitters have been developed. Both have full-scale ranges adjustable from 500 to 5000 microstrain and accuracies of ±2 percent. The “static” unit has response from dc to 1 KHz and the “dynamic” transmitter handles 30 Hz to 20 KHz. There are also two types of temperature transmitters. One accepts a variety of thermistor sensors for various measurement ranges between ?100°C and +600°C with accuracies of ±1°C. The other accepts various thermocouple inputs and has an accuracy of ±2 percent of range. These transmitters have been employed for a variety of industrial and scientific measurements. Some of the successful applications include transmission of strain and temperature data directly from pistons of reciprocating engines and from the compressor turbines of fan-jet engines. 相似文献
36.
37.
The electron bottleneck in normal metal-insulator-metal tunnel junctions due to nonequilibrium effects has been investigated in the presence of a magnetic field. The observed results are due to a new geometrical size effect and are explained in an extension of our nonequilibrium theory. 相似文献
38.
Adams J Adler C Aggarwal MM Ahammed Z Amonett J Anderson BD Anderson M Arkhipkin D Averichev GS Badyal SK Balewski J Barannikova O Barnby LS Baudot J Bekele S Belaga VV Bellwied R Berger J Bezverkhny BI Bhardwaj S Bhaskar P Bhati AK Bichsel H Billmeier A Bland LC Blyth CO Bonner BE Botje M Boucham A Brandin A Bravar A Cadman RV Cai XZ Caines H Calderón de la Barca Sánchez M Carroll J Castillo J Castro M Cebra D Chaloupka P Chattopadhyay S Chen HF Chen Y Chernenko SP Cherney M Chikanian A Choi B 《Physical review letters》2004,92(17):171801
Measurements of the production of forward high-energy pi(0) mesons from transversely polarized proton collisions at sqrt[s]=200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at x(F) below about 0.3, and becomes positive and large at higher x(F), similar to the trend in data at sqrt[s]< or =20 GeV. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with p(T)>1 GeV/c at a polarized proton collider. 相似文献
39.
Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Alexander J Amirikas R Aphecetche L Aronson SH Averbeck R Awes TC Azmoun R Babintsev V Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bazilevsky A Belikov S Berdnikov Y Bhagavatula S Boissevain JG Borel H Borenstein S Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X Chai JS Chand P Chang WC Chernichenko S Chi CY Chiba J Chiu M Choi IJ Choi J Choudhury RK Chujo T 《Physical review letters》2004,93(9):092301
Event-by-event fluctuations of the average transverse momentum of produced particles near midrapidity have been measured by the PHENIX Collaboration in square root of (sNN)=200 GeV Au+Au, and p+p collisions at the Relativistic Heavy Ion Collider. The fluctuations are observed to be in excess of the expectation for statistically independent particle emission for all centralities. The excess fluctuations exhibit a dependence on both the centrality of the collision and on the pT range over which the average is calculated. Both the centrality and pT dependence can be well reproduced by a simulation of random particle production with the addition of contributions from hard-scattering processes. 相似文献
40.
Coupling femtosecond light pulses from an all-fiber Er:laser system into a dispersion-shifted and highly non-linear fiber, we generate output spectra exhibiting two broadband and mutually coherent maxima. Depending on the chirp of the input pulse, the spectral separation is easily tunable over a wide range up to values exceeding 100 THz. In this way, the source provides access to an ultrabroadband wavelength interval from 1130 to 1950 nm. Because of soliton effects, the long-wave component exhibits a transform-limited pulse width of 40 fs directly after the nonlinear element. The high-frequency part propagating in the dispersive regime is recompressed to pulse durations as short as 24 fs with an optimized prism sequence. 相似文献