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   1113篇
  免费   31篇
  国内免费   6篇
化学   757篇
晶体学   29篇
力学   30篇
数学   169篇
物理学   165篇
  2023年   13篇
  2022年   9篇
  2021年   15篇
  2020年   17篇
  2019年   14篇
  2018年   22篇
  2017年   21篇
  2016年   32篇
  2015年   25篇
  2014年   33篇
  2013年   60篇
  2012年   101篇
  2011年   90篇
  2010年   43篇
  2009年   48篇
  2008年   76篇
  2007年   66篇
  2006年   50篇
  2005年   36篇
  2004年   43篇
  2003年   43篇
  2002年   37篇
  2001年   5篇
  2000年   12篇
  1999年   16篇
  1998年   11篇
  1997年   12篇
  1996年   15篇
  1995年   11篇
  1994年   6篇
  1992年   8篇
  1991年   11篇
  1990年   11篇
  1989年   12篇
  1988年   4篇
  1987年   4篇
  1985年   8篇
  1984年   11篇
  1983年   4篇
  1982年   7篇
  1981年   12篇
  1980年   8篇
  1979年   4篇
  1978年   11篇
  1977年   4篇
  1976年   10篇
  1975年   5篇
  1974年   4篇
  1973年   10篇
  1972年   4篇
排序方式: 共有1150条查询结果,搜索用时 15 毫秒
81.

Background  

LAG-3 (CD223) is a natural high affinity ligand for MHC class II. The soluble form (sLAG-3) induces maturation of monocyte-derived dendritic cells in vitro and is used as a potent Th1-like immune enhancer with many antigens in animal models. To extend this observation to human, a proof of concept study was conducted with a clinical-grade sLAG-3, termed IMP321, coinjected with alum-non-absorbed recombinant hepatitis B surface antigen.  相似文献   
82.
The electroreduction of a mixture of SO2 and CF3Br in DMF, in an undivided cell with a soluble anode (Mg or Zn) lead to salt of trifluoromethane sulfinic acid in high yield.  相似文献   
83.
Aqueous emulsion polymerizations of styrene were performed in the presence of a macromolecular reversible addition‐fragmentation chain transfer (RAFT) agent (macroRAFT) composed of acrylic acid (AA) and poly(ethylene oxide) methyl ether acrylate (PEOA), end‐capped by a reactive dodecyl trithiocarbonate group (P(AA‐co‐PEOA)‐TTC). The influence of the stirring speed or the presence of different amounts of a divalent salt, CaCl2, were investigated in this polymerization‐induced self‐assembly process, in which spherical and nonspherical nano‐objects were formed upon the synthesis of amphiphilic diblock copolymers in situ. It appeared that the addition of CaCl2 led to the controlled formation of different nano‐objects such as spheres, fibers or vesicles, whereas an appropriate stirring speed was required for the formation of nanofibers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   
84.
We define new families of noncommutative symmetric functions and quasi-symmetric functions depending on two matrices of parameters, and more generally on parameters associated with paths in a binary tree. Appropriate specializations of both matrices then give back the two-vector families of Hivert, Lascoux, and Thibon and the noncommutative Macdonald functions of Bergeron and Zabrocki.  相似文献   
85.
A library of resorcylic acid lactones (RAL) containing a cis‐enone moiety targeting kinases bearing a cysteine residue within the ATP‐binding pocket was prepared using a fluorous‐mixture synthesis and evaluated against a panel of 19 kinases thus providing important structure–activity trends. Two new analogues were then profiled for their selectivity against a panel of 402 kinases providing the broadest evaluation of this pharmacophores’ selectivity.  相似文献   
86.
Nonparametric inference under competing risks and selection-biased sampling   总被引:1,自引:0,他引:1  
The aim of this paper is to carry out statistical inference in a competing risks setup when only selection-biased observation of the data of interest is available. We introduce estimators of the cumulative incidence functions and study their joint large sample behavior.  相似文献   
87.
Cellulose microfibrils extracted by various alkaline treatments of vascular bundles from banana rachis were used to elaborate films. The films were comparatively studied to determine changes in polarity induced by various treatments. Atomic force microscopy was used to characterize the surface morphology of the films and transmission electron microscopy was employed to characterize the microfibrils used to elaborate the films. Contact angles were measured to determine surface free energy (SFE) and thermogravimetric analyses were carried out to determine changes in composition of the films. The results showed that the films of cellulose microfibrils prepared by the peroxide alkaline (PA) and peroxide alkaline-hydrochloric acid (PA-HCl) treatments had lower content of non-cellulosic constituents like xylose and had lower SFE than films of microfibrils treated with KOH-5. Furthermore, specimens treated with the most concentrated KOH solution (18 wt%) and sodium chloride presented the highest SFE and polar component.  相似文献   
88.
89.
Summary In the definition of semi-open sets and other kinds of generalized open sets, the role of the starting topology is given to a generalized topology. Some properties of the classes of sets so obtained is examined.  相似文献   
90.
The Zak?odzie meteorite is primitive enstatite achondrite. Mössbauer spectra of powdered samples of the Zak?odzie meteorite were obtained. Results from Mössbauer spectroscopy were compared with results from electron microprobe measurements.  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