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   117940篇
  免费   29107篇
  国内免费   21474篇
化学   78451篇
晶体学   1404篇
力学   7764篇
综合类   484篇
数学   14611篇
物理学   65807篇
  2024年   514篇
  2023年   1541篇
  2022年   1823篇
  2021年   1957篇
  2020年   2616篇
  2019年   3097篇
  2018年   2744篇
  2017年   3131篇
  2016年   4085篇
  2015年   4232篇
  2014年   4501篇
  2013年   6932篇
  2012年   8026篇
  2011年   9615篇
  2010年   11660篇
  2009年   11783篇
  2008年   5915篇
  2007年   5270篇
  2006年   4701篇
  2005年   4710篇
  2004年   5136篇
  2003年   4300篇
  2002年   4188篇
  2001年   4206篇
  2000年   3200篇
  1999年   3486篇
  1998年   2874篇
  1997年   2677篇
  1996年   3055篇
  1995年   3320篇
  1994年   3318篇
  1993年   3261篇
  1992年   2861篇
  1991年   2486篇
  1990年   2062篇
  1989年   2092篇
  1988年   2006篇
  1987年   1288篇
  1986年   1324篇
  1985年   983篇
  1984年   1072篇
  1982年   925篇
  1981年   775篇
  1980年   788篇
  1979年   544篇
  1978年   548篇
  1977年   656篇
  1976年   1061篇
  1973年   447篇
  1972年   546篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
1.
Journal of Radioanalytical and Nuclear Chemistry - Eco-friendly and low-cost composite, amidoxime-functionalized microcrystalline cellulose/mesoporous silica (MCC/MS-AO), were synthesized by...  相似文献   
2.
3.
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   
4.
The artificially accurate design of nonmetal electrocatalysts’ active site has been a huge challenge because no pure active species with the specific structure could be strictly controlled by traditional synthetic methods. Species with a multiconfiguration in the catalyst hinder identification of the active site and the subsequent comprehension of the reaction mechanism. We have developed a novel electro-assisted molecular assembly strategy to obtain a pure pentagon ring on perfect graphene avoiding other reconstructed structures. More importantly, the active atom was confirmed by the subtle passivation process as the topmost carbon atom. Recognition of the carbon-defect electrocatalysis reaction mechanism was first downsized to the single-atom scale from the experimental perspective. It is expected that this innovative electro-assisted molecular assembly strategy could be extensively applied in the active structure-controlled synthesis of nonmetal electrocatalysts and verification of the exact active atom.  相似文献   
5.
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   
6.
Journal of Radioanalytical and Nuclear Chemistry - This study presents a time-efficient method of analysing 210Pb, 210Bi, and 210Po in natural waters. The optimum pH (1.00), temperature...  相似文献   
7.
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   
8.
Huang  I-Chiau  Jafari  Raheleh 《Semigroup Forum》2021,103(3):899-915

Numerical semigroup rings are investigated from the relative viewpoint. It is known that algebraic properties such as singularities of a numerical semigroup ring are properties of a flat numerical semigroup algebra. In this paper, we show that arithmetic and set-theoretic properties of a numerical semigroup ring are properties of an equi-gcd numerical semigroup algebra.

  相似文献   
9.
黄卫良 《物理通报》2021,(4):133-134
单匝线圈在辐向磁场中的受力情况,很多教师都用纯数学方法(微元法)推导出其有效长度为线圈周长.文章用音频电流通过方形线圈,依次增加磁铁的个数让学生感觉音量的变化,并进一步合理外推出同样的结论.不仅能让学生体会基于实验合理外推这一科学的研究方法,还能让学生对扬声器的工作原理有清晰的认识.  相似文献   
10.
Huang  Renpei  Chen  Li  Yuan  Xiaoru 《显形杂志》2021,24(2):317-330
Journal of Visualization - Forecast calibration methods based on historical similar atmospheric state are effective means weather forecast accuracy. Conventional approaches search similar forecasts...  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