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   105600篇
  免费   18308篇
  国内免费   10357篇
化学   71586篇
晶体学   1218篇
力学   6924篇
综合类   534篇
数学   11928篇
物理学   42075篇
  2024年   369篇
  2023年   2134篇
  2022年   3651篇
  2021年   3881篇
  2020年   4256篇
  2019年   4148篇
  2018年   3561篇
  2017年   3298篇
  2016年   5199篇
  2015年   4961篇
  2014年   6045篇
  2013年   7815篇
  2012年   9475篇
  2011年   9815篇
  2010年   6493篇
  2009年   6219篇
  2008年   6586篇
  2007年   6066篇
  2006年   5547篇
  2005年   4630篇
  2004年   3428篇
  2003年   2696篇
  2002年   2435篇
  2001年   2006篇
  2000年   1776篇
  1999年   2079篇
  1998年   1850篇
  1997年   1722篇
  1996年   1895篇
  1995年   1502篇
  1994年   1459篇
  1993年   1168篇
  1992年   1069篇
  1991年   986篇
  1990年   791篇
  1989年   563篇
  1988年   464篇
  1987年   382篇
  1986年   374篇
  1985年   318篇
  1984年   241篇
  1983年   154篇
  1982年   142篇
  1981年   106篇
  1980年   76篇
  1979年   44篇
  1978年   34篇
  1976年   36篇
  1975年   33篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Photoactivated chemotherapy (PACT) has appealing merits over traditional chemotherapy as well as photodynamic therapy (PDT) by virtue of its spatial and temporal control on drug activity and oxygen-independent mechanisms of action. However, the short photoactivation wavelengths, e.g., visible light–activated Ru(II)-based PACT agents, limit the clinical application severely. In this work, a facile construction of supramolecular nanoparticles from a poly(ethylene glycol) (PEG)-modified [Ru(dip)2(py-SO3)]+ (abbreviated as Ru-PEG, dip = 4,7-diphenyl-1,10-phenanthroline, py-SO3 = pyridine-2-sulfonate) and 1,3-phenylenebis(pyren-1-ylmethanone) (BP) is shown. While Ru-PEG may undergo photoinduced ligand dissociation and release anticancer species of [Ru(dip)2(H2O)2]2+, BP has extremely large two-photon absorption cross sections (δ2) in the NIR region and intense fluorescence over the wavelengths where Ru-PEG has strong absorption. Thus, two-photon excitation of BP followed by an efficient Förster resonance energy transfer (FRET) from BP to Ru-PEG may lead to a potent inactivation against cisplatin-resistant cancer cells and 3D multicellular tumor spheroids (MCTSs). The residue fluorescence of BP also allows the cellular uptake of the particles to be visualized. This work provides a universal and convenient strategy to realize theranostic PACT in the ideal phototherapeutic window of 650–900 nm.  相似文献   
52.
Wu  Xuze  Sun  Yu  Wang  Yu  Chen  Yu 《Nonlinear dynamics》2020,99(3):1937-1958
Nonlinear Dynamics - Oblique collisions are more likely to happen in the realistic translational joint with clearance, compared to the full front impacts. It can be a quite demanding task to...  相似文献   
53.
54.
A new approach has been developed to improve SO2 sorption by cyano‐containing ionic liquids (ILs) through tuning the basicity of ILs and cyano–sulfur interaction. Several kinds of cyano‐containing ILs with different basicity were designed, prepared, and used for SO2 capture. The interaction between these cyano‐containing ILs and SO2 was investigated by FTIR and NMR methods. Spectroscopic investigations and quantum chemical calculations showed that dramatic effects on SO2 capacity originate from the basicity of the ILs and enhanced cyano–sulfur interaction. Furthermore, the captured SO2 was easy to release by heating or bubbling N2 through the ILs. This efficient and reversible process, achieved by tuning the basicity of ILs, is an excellent alternative to current technologies for SO2 capture.  相似文献   
55.
56.
57.
58.
Journal of Solid State Electrochemistry - Due to their distinctive chemical, electronic, and environmental properties, polypyrrole is used as a blocking barrier for methanol leakage in direct...  相似文献   
59.
The Ramanujan Journal - Inspired by Andrews and Merca’s recent work on the number of even parts over all partitions into distinct parts, we introduce a new kind of Beck type identities, which...  相似文献   
60.
The design and exploration of efficient, stable and environmentally compatible organic emitters for an electrochemiluminescence (ECL) sensor is a promising topic. Herein, a novel environmentally-friendly luminophore, ZnBCBTP@MWCNTs, were fabricated via self-assembly of porphyrin molecules (ZnBCBTP) onto multi-walled carbon nanotubes (MWCNTs). The resulting luminophore ZnBCBTP@MWCNTs displayed not only the highly ECL property and but also the good accelerated electron mobility. Then, a label-free ECL biosensor based ZnBCBTP@MWCNTs was constructed for the ultrasensitive detection of uric acid. Excitingly, this proposed ECL biosensor performed a good linear relationship in the range of 0–300 μM with a low detection limit of 1.4 μM, thus offering another reliable and feasible sensing platform for clinical bioanalysis with good selectivity, stability, and repeatability.  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