全文获取类型
收费全文 | 28348篇 |
免费 | 5331篇 |
国内免费 | 4025篇 |
学科分类
数理化 | 37704篇 |
出版年
2024年 | 65篇 |
2023年 | 608篇 |
2022年 | 752篇 |
2021年 | 1093篇 |
2020年 | 1295篇 |
2019年 | 1255篇 |
2018年 | 1088篇 |
2017年 | 1063篇 |
2016年 | 1549篇 |
2015年 | 1496篇 |
2014年 | 1876篇 |
2013年 | 2325篇 |
2012年 | 2800篇 |
2011年 | 2834篇 |
2010年 | 2004篇 |
2009年 | 1836篇 |
2008年 | 2110篇 |
2007年 | 1763篇 |
2006年 | 1583篇 |
2005年 | 1306篇 |
2004年 | 976篇 |
2003年 | 747篇 |
2002年 | 690篇 |
2001年 | 564篇 |
2000年 | 488篇 |
1999年 | 499篇 |
1998年 | 391篇 |
1997年 | 325篇 |
1996年 | 382篇 |
1995年 | 338篇 |
1994年 | 259篇 |
1993年 | 211篇 |
1992年 | 201篇 |
1991年 | 196篇 |
1990年 | 155篇 |
1989年 | 132篇 |
1988年 | 102篇 |
1987年 | 81篇 |
1986年 | 77篇 |
1985年 | 56篇 |
1984年 | 34篇 |
1983年 | 29篇 |
1982年 | 18篇 |
1981年 | 18篇 |
1980年 | 9篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1957年 | 9篇 |
1936年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Yuanbo Gao Tingting Yang Xueli Wang Jizong Chen Yong He 《Journal of polymer science. Part A, Polymer chemistry》2022,60(10):1610-1623
Two series of novel alternating copolyoxamides (PAnT-alt-n2 and PAn2-alt-62) are synthesized via solution/solid-state polycondensation (SSP). The alternating structures are analyzed carefully with 1H NMR and 13C NMR spectra. The melting behaviors, thermal stabilities, crystal structures and crystallinities are systematically evaluated by DSC, TGA and WAXD. The results reveal that these alternating copolyoxamides possess almost perfect alternating chain structures and have high melting temperature (Tm > 270 °C), high crystallinity (Xc > 32%) and high decomposition temperature (T5 > 405 °C) as well as low saturated water absorption (<3.5 wt%), which suggests that they have high potential as engineering plastic of high heat resistant. 相似文献
2.
Nonlinear Dynamics - The perovskite solar cell (PSC) is one of the most promising photovoltaic candidates along with the highly increasing demand for green electricity. One of the main concerns... 相似文献
3.
Yujie Gao Zhiye Qiu Lei Liu Mengmeng Li Bingjie Xu Dan Yu Dongming Qi Jindan Wu 《Journal of polymer science. Part A, Polymer chemistry》2022,60(15):2191-2212
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.
Tian Xiu-Zhi Yang Rui Ma Jia-Jia Ni Yong-Hao Deng Hai-Bo Dai Lei Tan Jiao-Jun Zhang Mei-Yun Jiang Xue 《高分子科学》2022,40(7):789-798
Chinese Journal of Polymer Science - Antistatic and strength properties are of vital importance for polyurethane rubber used in moving parts of many industrial instruments. Herein, polyurethane was... 相似文献
6.
7.
Liu Jun-Wei Shen Shu-Qian Li Ming Li Lei 《International Journal of Theoretical Physics》2021,60(5):1712-1719
International Journal of Theoretical Physics - Quantum coherence, coming from quantum superposition, occupies a significant position in the field of physics. We put forward a lower bound of the... 相似文献
8.
9.
Hu Duo-Duo Gao Qian Dai Jing-Cheng Cui Ru Li Yuan-Bo Li Yuan-Ming Zhou Xiao-Guo Bian Kang-Jie Wu Bing-Bing Zhang Kai-Fan Wang Xi-Sheng Li Yan 《中国科学:化学(英文版)》2022,65(4):753-761
Science China Chemistry - A light-induced, nickel-catalyzed three-component arylsulfonation of 1,3-enynes in the absence of photocatalyst is reported. This methodology exhibited mild conditions,... 相似文献
10.
Science China Mathematics - Linear factor models are familiar tools used in many fields. Several pioneering literatures established foundational theoretical results of the quasi-maximum likelihood... 相似文献