全文获取类型
收费全文 | 10888篇 |
免费 | 225篇 |
国内免费 | 28篇 |
专业分类
化学 | 7035篇 |
晶体学 | 103篇 |
力学 | 215篇 |
数学 | 1680篇 |
物理学 | 2108篇 |
出版年
2020年 | 97篇 |
2016年 | 200篇 |
2015年 | 162篇 |
2014年 | 150篇 |
2013年 | 370篇 |
2012年 | 342篇 |
2011年 | 381篇 |
2010年 | 244篇 |
2009年 | 270篇 |
2008年 | 356篇 |
2007年 | 356篇 |
2006年 | 358篇 |
2005年 | 338篇 |
2004年 | 265篇 |
2003年 | 267篇 |
2002年 | 258篇 |
2001年 | 199篇 |
2000年 | 212篇 |
1999年 | 159篇 |
1998年 | 150篇 |
1997年 | 154篇 |
1996年 | 182篇 |
1995年 | 184篇 |
1994年 | 143篇 |
1993年 | 170篇 |
1992年 | 184篇 |
1991年 | 177篇 |
1990年 | 137篇 |
1989年 | 152篇 |
1988年 | 145篇 |
1987年 | 140篇 |
1986年 | 137篇 |
1985年 | 201篇 |
1984年 | 188篇 |
1983年 | 164篇 |
1982年 | 174篇 |
1981年 | 198篇 |
1980年 | 117篇 |
1979年 | 161篇 |
1978年 | 149篇 |
1977年 | 174篇 |
1976年 | 138篇 |
1975年 | 158篇 |
1974年 | 138篇 |
1973年 | 137篇 |
1972年 | 94篇 |
1971年 | 99篇 |
1968年 | 113篇 |
1967年 | 130篇 |
1966年 | 127篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
E. Casarejos P. Armbruster L. Audouin J. Benlliure M. Bernas A. Boudard R. Legrain S. Leray B. Mustapha S. Czajkowski T. Enqvist B. Fernandez J. Pereira M. Pravikoff F. Rejmund K. -H. Schmidt C. Stephan J. Taieb L. Tassan-Got C. Villagrasa C. Volant W. Wlazlo 《Physics of Atomic Nuclei》2003,66(8):1413-1420
The isotopic production cross sections of heavy residues in relativistic heavy-ion collisions have been investigated in inverse kinematics. The primary reaction products were fully identified in mass and atomic number prior to beta decay using the fragment separator FRS. The huge collection of data obtained helps in the understanding of the two main reaction mechanisms involved: fragmentation and fission. These data provide basic information for future radioactive ion beam facilities and for technical applications like intense neutron sources by means of spallation targets. 相似文献
42.
43.
Lui Lam Flonnie Dowell Helmut Brand Guenter Ahlers 《Journal of statistical physics》1991,64(5-6):899-901
44.
We further study the validity of the Monte Carlo Hamiltonian method. The advantage of the method,in comparison with the standard Monte Carlo Lagrangian approach, is its capability to study the excited states. Weconsider two quantum mechanical models: a symmetric one V(x) = |x|/2; and an asymmetric one V(x) = ∞, forx < 0 and V(x) = x, for x ≥ 0. The results for the spectrum, wave functions and thermodynamical observables are inagreement with the analytical or Runge-Kutta calculations. 相似文献
45.
46.
Mesophase behaviour of 2,5-dibenzoyloxy-p-benzoquinone derivatives and tetrahydrobenzene tetraesters
Sibylle Berg Volker Krone Helmut Ringsdorf Udo Quotschalla Helmut Paulus 《Liquid crystals》1991,9(2):151-163
The synthesis of 2,5-dibenzoyloxy-p-benzoquinone derivatives, their products after reduction and tetraesters from tetrahydroxybenzene prepared from those products is described. Their phase behaviour was investigated by differential scanning calorimetry and polarizing microscopy and is discussed in terms of their detailed structure. 相似文献
47.
Patrick Mather Nino Grizzuti Glenn Heffner Mathias Ricker Willie E. Rochefort Markus Seitz Hans-Werner Schmidt Dale S. Pearson 《Liquid crystals》1994,17(6):811-826
In this paper, we report on the synthesis and detailed characterization of a new semiflexible nematic liquid crystalline polyester which could serve as a 'model' polyester for a variety of physical and physico-chemical investigations. The polymer is a nematic liquid over a wide temperature range-from the glass transition temperature at ∼95°C to the isotropic transition at ∼240°C. We expect this polyester to be particularly useful for studying the effect of flow on the orientation of liquid crystalline polymers, as well as the production and removal of disclinations. 相似文献
48.
O. Kindel F. J. Herrmann L. Schmidt 《Journal of Radioanalytical and Nuclear Chemistry》1994,183(2):219-224
By simulation experiments with a 10–5 mol/l solution of iodododecane labeled with131I in n-dodecane the influence of various materials and conditions, which are possible in nuclear fuel reprocessing, has been investigated. The formation of decomposition products was detected via HPLC with a radioactivity monitor. By means of252Cf plasma-desorption mass spectrometry (PDMS) the decomposition products were identified. It was found that a temperature of 100°C favored the formation of iodoalkanes with chain lengths of C1 to C11. The presence of TBP(tri-n-butyl-phosphate) accelerated the decomposition of iodododecane. In pure TBP only iodobutane was formed as a decomposition product. 相似文献
49.
Steven Schmidt Gü nter Lattermann Ralf Kleppinger Joachim H. Wendorff 《Liquid crystals》1994,16(4):693-702
Liquid crystalline complexes with chromium, molybdenum and with tungsten as metallic centres are reported. 1,4,7-Trisubstituted 1,4,7-triazacyclononane and three carbonyl groups are coordinated in an octahedral geometry. The observed mesophases are characterized as disordered rectangular columnar of a pyramidic type. 相似文献
50.