全文获取类型
收费全文 | 424篇 |
免费 | 10篇 |
专业分类
化学 | 230篇 |
晶体学 | 7篇 |
力学 | 1篇 |
数学 | 17篇 |
物理学 | 179篇 |
出版年
2019年 | 2篇 |
2018年 | 2篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2013年 | 12篇 |
2012年 | 22篇 |
2011年 | 39篇 |
2010年 | 9篇 |
2009年 | 3篇 |
2008年 | 10篇 |
2007年 | 3篇 |
2006年 | 6篇 |
2005年 | 13篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 14篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1997年 | 2篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 12篇 |
1989年 | 8篇 |
1988年 | 12篇 |
1987年 | 16篇 |
1986年 | 10篇 |
1985年 | 8篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 16篇 |
1980年 | 5篇 |
1979年 | 13篇 |
1978年 | 3篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 11篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1968年 | 5篇 |
1967年 | 7篇 |
1954年 | 2篇 |
1890年 | 1篇 |
排序方式: 共有434条查询结果,搜索用时 15 毫秒
71.
72.
73.
H. Appel 《Zeitschrift für Physik A Hadrons and Nuclei》1959,155(5):580-594
Parity violation in beta decay was investigated by measuring the (beta, gamma) circular polarization correlation. The asymmetry coefficients were redetermined with higher accuracy for Co 60 (A=? 0,33±0,01) and Na 22 (A=+0,36±0,08). The cosΘ-dependence of the polarizationP was verified for the allowed beta transition of Co 60. Measurements on Zr 95 indicated a large GT-F-mixture and allowed to determine the relative magnitude of the matrix elements. For the first forbidden 2,3 MeV transition of Sb 124 the results are in agreement with the assumtion of an anomalously large value of the matrix elementB ij compared to all other nuclear matrix elements. 相似文献
74.
Thermal, base- and metal- induced 1,2-elimination reactions at P-halogen phosphanes of the type RP(Hal)-C(X)R1R2 were used for the preparation of phospha-alkenes with a new-type pattern of substitution at the (PC)-double-bond. The different methods are discussed in more detail. 相似文献
75.
76.
77.
Aaltonen T Álvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Appel JA Apresyan A Arisawa T Artikov A Asaadi J Ashmanskas W Auerbach B Aurisano A Azfar F Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Barria P Bartos P Bauce M Bauer G Bedeschi F Beecher D Behari S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Binkley M Bisello D Bizjak I Bland KR Blocker C Blumenfeld B Bocci A Bodek A Bortoletto D Boudreau J Boveia A Brau B Brigliadori L Brisuda A 《Physical review letters》2010,105(23):232003
We present a measurement of the top-quark width in the lepton+jets decay channel of tt events produced in p p collisions at Fermilab's Tevatron collider and collected by the CDF II detector. From a data sample corresponding to 4.3 fb(-1) of integrated luminosity, we identify 756 candidate events. The top-quark mass and the mass of the hadronically decaying W boson that comes from the top-quark decay are reconstructed for each event and compared with templates of different top-quark widths (Γ(t)) and deviations from nominal jet energy scale (Δ(JES)) to perform a simultaneous fit for both parameters, where Δ(JES) is used for the in situ calibration of the jet energy scale. By applying a Feldman-Cousins approach, we establish an upper limit at 95% confidence level (CL) of Γ(t) <7.6 GeV and a two-sided 68% CL interval of 0.3 GeV <Γ(t) <4.4 GeV for a top-quark mass of 172.5 GeV/c(2), which are consistent with the standard model prediction. 相似文献
78.
We develop a method for automatically symmetrizing Petrowsky well-posed Cauchy problems for constant coefficient linear partial differential equations. The method is rooted in the Sturm sequence technique for establishing the location of the roots of a complex polynomial and can be automated using standard symbolic computation tools. In the special case of homogeneous strictly hyperbolic scalar equations, we show that the resulting estimates are strong enough to control all principal order derivatives and thus can be used in place of the Leray energies. We also illustrate the method by applying it to various problems of mixed type. 相似文献
79.
This study was undertaken to better understand current regional opinions regarding vocal fold nodules in adult singers. A questionnaire was sent to 298 persons representing the 3 professional groups most involved with the care of singers with vocal nodules: otolaryngologists, speech pathologists, and teachers of singing. The questionnaire queried respondents about their level of experience with this problem, and their beliefs about causative factors, career impact, and optimum treatment. Responses within and between groups were similar, with differences between groups primarily in the magnitude of positive or negative responses, rather than in the polarity of the responses. Prevailing opinions included: recognition of causative factors in both singing and speaking voice practices, optimism about responsiveness to appropriate treatment, enthusiasm for coordinated voice therapy and voice training as first-line treatment, and acceptance of microsurgical management as appropriate treatment if behavioral management fails. 相似文献
80.
H. Mühe Mc. Candless E. Valenta Utz Wilh Vaubel B. Ahlström O. Aschan J. Kondakow J. Schindelmeiser R. Böhme H. Herzfeld J. E. Teeple R. Adan J. Marcusson Darmois H. Wolff C. Piest R. Marcille EA. Parry M. Adams H. W. Fosse K. Ihnatowzcz 《Analytical and bioanalytical chemistry》1917,56(10-11):541-560