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   265299篇
  免费   7063篇
  国内免费   4098篇
化学   129742篇
晶体学   3936篇
力学   14223篇
综合类   246篇
数学   41331篇
物理学   86982篇
  2022年   1568篇
  2021年   1744篇
  2020年   2046篇
  2019年   1891篇
  2018年   11206篇
  2017年   12043篇
  2016年   7141篇
  2015年   3462篇
  2014年   3354篇
  2013年   7350篇
  2012年   11128篇
  2011年   20794篇
  2010年   12554篇
  2009年   12296篇
  2008年   17393篇
  2007年   21011篇
  2006年   6021篇
  2005年   12873篇
  2004年   8439篇
  2003年   7699篇
  2002年   5406篇
  2001年   4435篇
  2000年   3632篇
  1999年   3034篇
  1998年   2601篇
  1997年   2500篇
  1996年   2661篇
  1995年   2467篇
  1994年   2171篇
  1993年   2079篇
  1992年   2258篇
  1991年   2169篇
  1990年   2064篇
  1989年   1990篇
  1988年   1986篇
  1987年   1953篇
  1986年   1802篇
  1985年   2381篇
  1984年   2487篇
  1983年   2088篇
  1982年   2361篇
  1981年   2168篇
  1980年   2200篇
  1979年   2192篇
  1978年   2317篇
  1977年   2141篇
  1976年   2206篇
  1975年   2130篇
  1974年   1963篇
  1973年   2208篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Yang  T. L.  Kao  C. L.  Kuo  C. E.  Yeh  H. C.  Li  W. J.  Li  H. T.  Chen  C. Y. 《Chemistry of Natural Compounds》2022,58(5):825-827
Chemistry of Natural Compounds - A novel bibenzyl derivative, hydrangchinenin (1), was isolated from the stems of Hydrangea chinensis Maxim. (Hydrangeaceae). Its structure was determined on the...  相似文献   
2.
Lin  Yu  Wu  Yeyu  Tan  Xuecai  Wu  Jiawen  Huang  Kejing  Mi  Yan  Ou  Panpan  Wei  Fucun 《Journal of Solid State Electrochemistry》2022,26(4):959-971
Journal of Solid State Electrochemistry - An ultrasensitive “signal-off–on” electrochemiluminescence (ECL) biosensor is constructed based on f1-TiO2/g-C3N4/PDA for thrombin...  相似文献   
3.
Refractory wounds have always been an important issue to healthcare systems, whose healing process is always delayed by multiple factors, including bacterial infections, chronic inflammation, and excessive exudates, etc. Employing multifunctional wound dressings is recognized as an effective strategy to deal with refractory wounds, which has yielded promising outcomes in recent years. Among these advanced wound dressings, fibrous dressings have gained growing attention due to their unique merits. Such wound dressings have demonstrated great potential in delivering theranostic agents, such as antibacterial agents, anti-inflammatory drugs, growth factors, and diagnostic probes, etc., for the purposes of accelerating wound healing. This paper reviews the development of multifunctional fibrous dressings and their applications in treating refractory wounds. The construction approaches of novel fibrous dressing with capabilities of antibacterial, anti-inflammation, exudate management and diagnosis were also introduced. Furthermore, the existing problems and challenges are also discussed briefly.  相似文献   
4.
5.
Hua  Saixiang  Zhu  Huichao  Wang  Xiao  Wu  Mingyuan  Wu  Qingyun  Liu  Jiuyi  Yang  Jianjun  Zhang  Jianan 《Cellulose (London, England)》2022,29(13):7465-7475
Cellulose - Ultraviolet (UV) protective cotton fabric is a convenient and reliable way to protect human body from sunlight. Herein, a polymerizable UV-absorber,...  相似文献   
6.
Theoretical and Mathematical Physics - Dynamic systems acting on the plane and possessing the Wada property have been observed. There exist only two topological types, symmetric and antisymmetric,...  相似文献   
7.
Chen  C. Y.  Kao  C. L.  Huang  S. T.  Kuo  C. E.  Song  P. L.  Li  W. J.  Hsu  L. T.  Li  H. T. 《Chemistry of Natural Compounds》2022,58(1):107-109
Chemistry of Natural Compounds -  相似文献   
8.
Li  Y.  Shi  W. H.  Dong  L. M.  Xu  S. X.  Huang  H. J.  Yin  J. R. 《Journal of Applied Spectroscopy》2022,89(3):534-541
Journal of Applied Spectroscopy - Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum,...  相似文献   
9.
Liu  Jingze  Fei  Qingguo  Wu  Shaoqing  Tang  Zhenhuan  Zhang  Dahai 《Nonlinear dynamics》2021,106(3):1869-1890
Nonlinear Dynamics - Rolling bearing and squeeze film damper will introduce structural nonlinearity into the dynamic model of aeroengine. Rubbing will occur due to the clearance reduction design of...  相似文献   
10.
Herein, we report a Mott-Schottky catalyst by entrapping cobalt nanoparticles inside the N-doped graphene shell (Co@NC). The Co@NC delivered excellent oxygen evolution activity with an overpotential of merely 248 mV at a current density of 10 mA cm–2 with promising long-term stability. The importance of Co encapsulated in NC has further been demonstrated by synthesizing Co nanoparticles without NC shell. The synergy between the hexagonal close-packed (hcp) and face-centered cubic (fcc) Co plays a major role to improve the OER activity, whereas the NC shell optimizes the electronic structure, improves the electron conductivity, and offers a large number of active sites in Co@NC. The density functional theory calculations have revealed that the hcp Co has a dominant role in the surface reaction of electrocatalytic oxygen evolution, whereas the fcc phase induces the built-in electric field at the interfaces with N-doped graphene to accelerate the H+ ion transport.  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