全文获取类型
收费全文 | 1215篇 |
免费 | 524篇 |
国内免费 | 90篇 |
专业分类
化学 | 245篇 |
晶体学 | 5篇 |
力学 | 99篇 |
综合类 | 28篇 |
数学 | 126篇 |
物理学 | 1326篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 25篇 |
2021年 | 44篇 |
2020年 | 59篇 |
2019年 | 25篇 |
2018年 | 31篇 |
2017年 | 73篇 |
2016年 | 70篇 |
2015年 | 81篇 |
2014年 | 126篇 |
2013年 | 90篇 |
2012年 | 110篇 |
2011年 | 106篇 |
2010年 | 86篇 |
2009年 | 88篇 |
2008年 | 103篇 |
2007年 | 106篇 |
2006年 | 82篇 |
2005年 | 70篇 |
2004年 | 58篇 |
2003年 | 50篇 |
2002年 | 47篇 |
2001年 | 47篇 |
2000年 | 36篇 |
1999年 | 34篇 |
1998年 | 37篇 |
1997年 | 24篇 |
1996年 | 15篇 |
1995年 | 16篇 |
1994年 | 6篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1957年 | 2篇 |
排序方式: 共有1829条查询结果,搜索用时 78 毫秒
71.
We have studied the properties of the relativistic helium fragments emitted from the projectile in the interactions of 24Mg ions accelerated at an energy of 3.7 A GeV with emulsion nuclei. The total, partial nuclear cross-sections and production rates of helium fragmentation channels in relativistic nucleus-nucleus collisions and their dependence on the mass and energy of the incident projectile nucleus are investigated. The yields of multiple helium projectile fragments disrupted from the interactions of 24Mg projectile nuclei with hydrogen H, light CNO and heavy AgBr groups of target emulsion nuclei are discussed and they indicate that the breakup mechanism of the projectile seems to be independent of the target mass. Limiting fragmentation behavior of fast-moving helium fragments is observed in both the projectile and target nuclei. The multiplicity distributions of helium projectile fragments emitted in the interactions of 24Mg projectile nuclei with the different target nuclei of the emulsion are well described by the KNO scaling presentation. The mean multiplicities of the different charged secondary particles, normally defined shower, grey and black ( ns, ng and nb) emitted in the interactions of 3.7 A GeV 24Mg with the different groups of emulsion nuclei at different ranges of projectile fragments are decreasing when the number of He fragments stripped from projectile increases. These values of ni ( i = s, g, b and h particles) in the events where the emission of fast helium fragments were accompanied by heavy fragments having Z 3 seem to be constant as the He multiplicity increases, and exhibit a behavior independent of the He multiplicity. 相似文献
72.
M. Sawicka I. Matea H. Grawe R. Grzywacz M. Pfützner M. Lewitowicz J. M. Daugas B. A. Brown A. Lisetskiy F. Becker G. Bélier C. Bingham R. Borcea E. Bouchez A. Buta E. Dragulescu G. de France G. Georgiev J. Giovinazzo F. Hammache F. Ibrahim P. Mayet V. Méot F. Negoita F. De Oliveira-Santos O. Perru O. Roig K. Rykaczewski M. G. Saint-Laurent J. E. Sauvestre O. Sorlin M. Stanoiu I. Stefan C. Stodel Ch. Theisen D. Verney J. Żylicz 《The European Physical Journal A - Hadrons and Nuclei》2004,22(3):455-459
A decay spectroscopy study of the neutron-rich cobalt isotopes has been performed using fragmentation of a 86Kr36+ beam and the new LISE2000 spectrometer at GANIL. For 71Co and 73Co, the -delayed radiation has been observed for the first time, and the half-lives were found to be 79(5) ms and 41(4) ms, respectively. Features of the decay are discussed qualitatively in terms of nuclear models. 相似文献
73.
We present the results of experimental determination of the coefficients of laser radiation reflection (1 10.6 m and 2 1.06 m) from dielectric targets of complex chemical composition in vacuum with allowance for a regime of developed plasma formation. 相似文献
74.
75.
76.
77.
78.
J. Benlliure T. Kurtukian-Nieto L. Audouin B. Blank F. Becker E. Casarejos D. Cortina M. Fernández-Ordóñez J. Giovinazzo D. Henzlova B. Jurado J. Pereira F. Rejmund K.-H. Schmidt O. Yordanov 《The European physical journal. Special topics》2007,150(1):309-310
The production of heavy neutron-rich nuclei is investigated using cold-fragmentation reactions.
More than 25 new heavy neutron-rich nuclei were produced in the fragmentation of 208Pb projectiles at 1 A GeV impinging a
beryllium target. The precise measurement of their production cross sections enables to benchmark the predictive power of
different
model calculations and make reliable predictions of the production rates expected in future radioactive beam facilities. 相似文献
79.
为了满足惯性约束聚变(ICF)和状态方程(EOS)实验以及靶装配工艺的需要,在薄膜轧制过程中间以及轧制工艺完成以后需要对镍膜进行热处理来改善其组织结构和力学性能。对多辊轧机冷轧的方法制备的厚11 mm镍膜中间退火工艺进行了研究,根据确定的合适的退火工艺退火后继续轧制得到成品镍膜厚7 mm,表面粗糙度小于50 nm,基本满足目前状态方程实验对箔膜的要求。金相显微照片表明镍膜晶粒经500 ℃保温1 h退火由轧制前的条带状变为等轴晶;镍膜硬度经500 ℃退火后由4 GPa降低到了2.3 GPa左右;XRD衍射测试表明镍膜经500 ℃以上温度退火后,高角度的衍射峰开始出现,织构得到一定程度的改善。由此可以确定镍膜合适的中间退火温度为520 ℃保温1 h。 相似文献
80.