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   765篇
  免费   27篇
  国内免费   1篇
化学   396篇
晶体学   22篇
力学   21篇
数学   184篇
物理学   170篇
  2024年   2篇
  2023年   4篇
  2022年   15篇
  2021年   16篇
  2020年   23篇
  2019年   22篇
  2018年   34篇
  2017年   31篇
  2016年   35篇
  2015年   27篇
  2014年   45篇
  2013年   160篇
  2012年   49篇
  2011年   49篇
  2010年   45篇
  2009年   28篇
  2008年   26篇
  2007年   24篇
  2006年   24篇
  2005年   5篇
  2004年   16篇
  2003年   8篇
  2002年   11篇
  2001年   8篇
  2000年   4篇
  1999年   9篇
  1998年   7篇
  1997年   3篇
  1996年   6篇
  1995年   6篇
  1994年   3篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1989年   6篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1980年   2篇
  1979年   5篇
  1977年   2篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1972年   4篇
  1971年   1篇
  1965年   1篇
  1956年   1篇
  1937年   1篇
排序方式: 共有793条查询结果,搜索用时 15 毫秒
101.
An experiment on rabbits was carried out with the aim to check results obtained formerly with the help of the neutron activation analysis indicating that Na+ ions can be /by contrast to K+ ions/ only very slowly removed from the bone tissue by extraction with water. The data resulting from a radiotracer experiment with22Na are in a good agreement with the above mentioned results.  相似文献   
102.
103.
Çiftçi  C.  Aytaç  A. 《Mathematical Notes》2021,109(3-4):517-526
Mathematical Notes - The vulnerability in a communication network is the measurement of the strength of the network against damage that occurs in nodes or communication links. It is important that...  相似文献   
104.
We present a method to identify the symmetry class of an elasticity tensor whose components are given with respect to an arbitrarily oriented coordinate system. The method is based on the concept of distance in the space of tensors, and relies on the monoclinic or transversely isotropic distance function. Since the orientation of a monoclinic or transversely isotropic tensor depends on two Euler angles only, we can plot the corresponding distance functions on the unit sphere in ℝ3 and observe the symmetry pattern of the plot. In particular, the monoclinic distance function vanishes in the directions of the normals of the mirror planes, so the number and location of the zeros allows us to identify the symmetry class and the orientation of the natural coordinate system. Observing the approximate locations of the zeros on the plot, we can constrain a numerical algorithm for finding the exact orientation of the natural coordinate system.  相似文献   
105.
Nonlinear Dynamics - Substitution Box (S-Box) is one of the most significant structures used to create an encryption which is strong and resistant against attacks in block encryption algorithms....  相似文献   
106.
107.
108.
This paper addresses conditions for the Abel method of limitability to imply convergence and subsequential convergence.   相似文献   
109.
In this work, we report a comprehensive theoretical investigation of electroactive star shaped pyrrole functionalized triazine monomer with two main goals. First goal of this work is to explore the physical and chemical properties of the monomer, then to investigate correlation between the experimental and the theoretical properties of monomer. The scale factor which is calculated from B3LYP/cc-pVDZ was determined as 0.985 for FT-IR and it is an important and reliable contribution to the literature. It is determined that the most appropriate basis set for this molecule. The other novel objective of this research is to investigate temperature effect on displacement of chlorine atoms in 2,4,6-trichloro-1,3,5-triazine. This method applied for the first time in the literature for triazines is especially crucial to the synthesis of unsymmetrical triazines.  相似文献   
110.
The use of highly purified immunoglobulin became among the most powerful adopted strategies in therapeutic trials nowadays. Their role as immunomodulatory and anti-inflammatory agents has widened their scope of use. A novel continuous supermacroporous monolithic cryogels embedded with histidine-epoxy-activated-sepharose beads were synthetized as a new monolithic adsorbents for the separation of immunoglobulin G from human serum. The histidine-epoxy-activated-sepharose beads were embedded into the 2-hydroxyethyl methacrylate (HEMA) cryogels present in frozen aqueous solution inside a plastic syringe. The microstructure morphology of the cryogels was characterized by swelling measurement and scanning electron microscopy. The adsorption of human IgG on the histidine-epoxy-activated-sepharose beads pHEMA cryogels appeared to follow the Langmuir–Freundlich adsorption isotherm model. The maximum IgG adsorption was observed at 4°C and pH 7.4 and was found to be 26.95 mg/g of cryogel which is close to that obtained experimentally (24.49 mg/g). The cryogels were used for several adsorption-desorption cycles without any negligible decrease in their adsorption capacity.  相似文献   
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