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   1206篇
  免费   178篇
  国内免费   177篇
化学   919篇
晶体学   11篇
力学   72篇
综合类   10篇
数学   114篇
物理学   435篇
  2023年   33篇
  2022年   31篇
  2021年   46篇
  2020年   79篇
  2019年   58篇
  2018年   42篇
  2017年   27篇
  2016年   66篇
  2015年   66篇
  2014年   57篇
  2013年   86篇
  2012年   113篇
  2011年   109篇
  2010年   73篇
  2009年   72篇
  2008年   78篇
  2007年   55篇
  2006年   72篇
  2005年   50篇
  2004年   28篇
  2003年   17篇
  2002年   23篇
  2001年   29篇
  2000年   17篇
  1999年   22篇
  1998年   24篇
  1997年   23篇
  1996年   16篇
  1995年   22篇
  1994年   10篇
  1993年   26篇
  1992年   14篇
  1991年   12篇
  1990年   12篇
  1989年   15篇
  1988年   7篇
  1987年   6篇
  1986年   2篇
  1985年   4篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1980年   4篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1968年   2篇
排序方式: 共有1561条查询结果,搜索用时 26 毫秒
41.
合成所得双(N-氧化吡啶-2-甲醛)缩1,2-丙二胺的镍(II)配合物[Ni(piopn)(H_2O)_2](ClO_4)_2的晶体属空间群C_s~4-C_c, 晶胞参数a=0.7397(3) nm, b=1.3187(7) nm, c=2.5502(14) nm, β=102.18(4)°. 用分子轨道理论的近似方法分析了该配合物的电子结构和分子轨道, 探讨了分子的结构特征与红外光谱的关系.  相似文献   
42.
Reaction-based fluorescent-probes have proven successful for the visualisation of biological species in various cellular processes. Unfortunately, in order to tailor the design of a fluorescent probe to a specific application (i.e. organelle targeting, material and theranostic applications) often requires extensive synthetic efforts and the synthetic screening of a range of fluorophores to match the required synthetic needs. In this work, we have identified Pinkment-OH as a unique “plug-and-play” synthetic platform that can be used to develop a range of ONOO responsive fluorescent probes for a variety of applications. These include theranostic-based applications and potential material-based/bioconjugation applications. The as prepared probes displayed an excellent sensitivity and selectivity for ONOO over other ROS. In vitro studies using HeLa cells and RAW 264.7 macrophages demonstrated their ability to detect exogenously and endogenously produced ONOO. Evaluation in an LPS-induced inflammation mouse model illustrated the ability to monitor ONOO production in acute inflammation. Lastly, theranostic-based probes enabled the simultaneous evaluation of indomethacin-based therapeutic effects combined with the visualisation of an inflammation biomarker in RAW 264.7 cells.

Pinkment, a resorufin based ONOO selective and sensitive ‘plug and play’ fluorescence-based platform for in vitro and in vivo use, enables facile functionalisation for various imaging and theranostic applications.  相似文献   
43.
Yaping Zou 《Tetrahedron letters》2007,48(27):4781-4784
A series of new diphosphite ligands have been easily prepared from BINOL derivatives; moderate enantioselectivities (up to 80% ee) and excellent regioselectivities (b/l up to 98/2) have been achieved in the Rh-catalyzed asymmetric hydroformylation of vinyl acetate.  相似文献   
44.
This paper reports that an ionic liquid (IL) has been prepared by directly mixing InCl3 and 1-methyl-3-ethylimidazolium chloride (EMIC) with molar ratio 1/1 under dry argon atmosphere. The densities, and surface tension of the pure IL were determined at temperature range of 293.15 to 343.15 ± 0.1 K. The volumetric properties and the properties of surface for ionic liquid based on group III were discussed by Glasser's theory and Yang's interstice model.  相似文献   
45.
The equilibrium molalities In3+ in {In2(SO4)3 + Na2SO4 + HDEHMTPCA + n-C8H18 + water} were measured at ionic strength from (0.1 to 2.0) mol · kg−1 containing Na2SO4 as supporting electrolyte in aqueous phase and at constant molality extractant at temperatures from (278.15 to 303.15) K in organic phase. The standard extraction constants K0 at various temperatures were obtained by methods of extrapolation and polynomial approximation. Thermodynamic quantities for the extraction process were calculated.  相似文献   
46.
47.
臧二乐  梁树权 《应用化学》1995,12(3):107-108
磷钼酸四氢三铵的制备及其交换性能臧二乐,梁树权(北京农业大学应用化学系北京100094)(中国院学院化学研究所北京)关键词磷钼酸四氢三铵,制备,离子交换性能通式为M_nXY_(12)O_(40)·pH_2O(其中M为一价阳离子;X为P、As、Si、G...  相似文献   
48.
49.
A novel electrochemical approach has been proposed to measure the interface potential at the electrode/solution interface based on reconstructing the three‐electrode system of a potentiostat. In this work, the method was investigated both theoretically and experimentally. Mathematical expressions, describing current? potential characteristics, were derived. Zero current potential Ezcp was defined as the potential at which the current is zero based on linear sweep voltammetry, and was determined from the I? E curve to measure the interface potential. The experimental results obtained with the couples Fe(CN)63?/Fe(CN)64? and Co(NH3)63+/Co(NH3)62+ as examples agreed well with the theory. The proposed approach exhibits an excellent performance for measuring the interface potential due to the advantages of rapidity, high stability and accuracy.  相似文献   
50.
Through a two-step vacuum-filtration process, WSe2 and MoS2 nanosheets were sequentially deposited onto a polymeric nanoporous support, forming WSe2/MoS2 bi-layered heterostructure. Highly rectified ion transport phenomenon is observed through the heterogeneous 2D layered membranes.  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