首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   356篇
  免费   0篇
化学   180篇
力学   24篇
数学   31篇
物理学   121篇
  2020年   3篇
  2019年   5篇
  2017年   3篇
  2016年   3篇
  2014年   11篇
  2013年   9篇
  2012年   11篇
  2011年   6篇
  2010年   8篇
  2009年   13篇
  2008年   5篇
  2007年   9篇
  2006年   14篇
  2005年   7篇
  2004年   10篇
  2003年   13篇
  2002年   8篇
  2001年   7篇
  2000年   4篇
  1999年   5篇
  1998年   9篇
  1996年   9篇
  1995年   2篇
  1994年   3篇
  1993年   4篇
  1991年   2篇
  1990年   4篇
  1989年   7篇
  1988年   5篇
  1987年   2篇
  1986年   4篇
  1985年   4篇
  1984年   8篇
  1983年   8篇
  1982年   4篇
  1981年   7篇
  1980年   4篇
  1979年   3篇
  1978年   6篇
  1977年   11篇
  1976年   18篇
  1975年   11篇
  1974年   18篇
  1973年   11篇
  1972年   6篇
  1971年   6篇
  1969年   3篇
  1968年   3篇
  1967年   3篇
  1963年   3篇
排序方式: 共有356条查询结果,搜索用时 10 毫秒
1.
The thermal stabilities of limestone with varied content of iron are compared. The nature of the differences observed is discussed.  相似文献   
2.
Results of investigations into the physical properties of a number of new nonlinear crystals are presented. The parameters of frequency converters manufactured on their basis are compared, and second-harmonic generation of CO2 lasers first excited by frequency conversion in LiInSe2, AgGa1– x InxSe2, AgxGaxGexS2(1 + x), and Hg1–x CdxGa2S4 crystals is investigated. The superiority of HgGa2S4, Hg1–x CdxGa2S4, and AgGa1–x InxSe2 over the well-known crystals has been demonstrated for frequency conversion both within the middle-IR range and from the visible range to the middle-IR range. Advantages of LiInSe2 and AgGa1–x InxSe2 crystals are demonstrated for the direct frequency conversion of femtosecond laser radiation to the middle-IR range compared to the cascade frequency conversion and direct frequency conversion in LiInS2 crystals.  相似文献   
3.
This paper discusses monitoring electromagnetic fields (natural and artificial) in the atmosphere. Methods are described for remote sensing of the atmosphere and surface in order to examine static and alternating electromagnetic-energy fluxes in the biosphere.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 69–79, December, 1991.  相似文献   
4.
The problems of determining and investigating the informative parameters of atmospheric electricity are discussed. It is shown that short-period variations in atmospheric electricity are ecologically significant. An automated system for monitoring atmospheric electricity and a method of processing the results of measurements are described. V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 88–98, May, 1998.  相似文献   
5.
6.
7.
Supramolecular organization of complexes formed by poly(N-ethyl-4-vinylpyridinium bromide) and sodium dodecylsulfate in aqueous salt solutions was studied as a function of temperature and concentration of the complexes. It was shown that a decrease in temperature and/or concentration of complexes led to their reversible disaggregation into a molecularly dispersed (“unipolymer”) state. The ratio between the components in complex particles remained unchanged in this case. It was first found that phase separation in aqueous solutions of the complexes upon temperature elevation is accompanied by the precipitation of a nonstoichiometric complex.  相似文献   
8.
The composition of the essential oil of wild bergamot bee balm introduced into the Krasnodarsk Krai has been analyzed by chromatomass spectrometry. The essential oil contains 34 components of which the main ones are -pinene (3.5%), -pinene (2.9%), -terpinene (1.7%), p-cymene (32.5), an aliphatic aldehyde (6.3%), sabinene hydrate (1.9%), -caryophyllene (1.1%), the methyl ether of carvacrol (5.5%), citronellyl acetate (1.6%), thymol (12.6%), and carvacrol (24.0%). The compounds were identified on the basis of their mass-spectrometric characteristics and arithmetical retention indices.A. N. Severtsov Institute of Animal Evolutionary Morphology and Ecology, Academy of Sciences of the USSR, Moscow. All-Union Scientific-Research Institute of Drugs, Moscow. Translated from Khimiya Prirodnykh Soedinenii, Vol. 5, pp. 646–649, September–October, 1989.  相似文献   
9.
The influence of the electrolysis conditions and electrolyte composition on the cathodic current efficiency by the alloy and on the alloy composition was studied for electrodeposition of the palladium-zinc alloy from an aminoacetic electrolyte.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号