全文获取类型
收费全文 | 24996篇 |
免费 | 4362篇 |
国内免费 | 2849篇 |
专业分类
化学 | 18412篇 |
晶体学 | 256篇 |
力学 | 1447篇 |
综合类 | 149篇 |
数学 | 2591篇 |
物理学 | 9352篇 |
出版年
2024年 | 26篇 |
2023年 | 565篇 |
2022年 | 535篇 |
2021年 | 807篇 |
2020年 | 1086篇 |
2019年 | 1018篇 |
2018年 | 876篇 |
2017年 | 775篇 |
2016年 | 1188篇 |
2015年 | 1164篇 |
2014年 | 1450篇 |
2013年 | 1912篇 |
2012年 | 2306篇 |
2011年 | 2415篇 |
2010年 | 1680篇 |
2009年 | 1521篇 |
2008年 | 1736篇 |
2007年 | 1554篇 |
2006年 | 1370篇 |
2005年 | 1182篇 |
2004年 | 900篇 |
2003年 | 773篇 |
2002年 | 692篇 |
2001年 | 488篇 |
2000年 | 498篇 |
1999年 | 471篇 |
1998年 | 417篇 |
1997年 | 377篇 |
1996年 | 364篇 |
1995年 | 315篇 |
1994年 | 323篇 |
1993年 | 246篇 |
1992年 | 225篇 |
1991年 | 168篇 |
1990年 | 173篇 |
1989年 | 138篇 |
1988年 | 91篇 |
1987年 | 73篇 |
1986年 | 62篇 |
1985年 | 56篇 |
1984年 | 36篇 |
1983年 | 20篇 |
1982年 | 28篇 |
1981年 | 15篇 |
1980年 | 22篇 |
1979年 | 7篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 29 毫秒
1.
Nonlinear Dynamics - At present, the main measures for disease control are vaccination, quarantine and treatment. Taking the three measures into consideration, time-varying optimal control problems... 相似文献
2.
3.
Song Zi-Long Zhu Yun Liu Jing-Rui Guo Shu-Ke Gu Yu-Cheng Han Xinya Dong Hong-Qiang Sun Qi Zhang Wei-Hua Zhang Ming-Zhi 《Molecular diversity》2021,25(1):205-221
Molecular Diversity - Based on the strategy of diversity-oriented synthesis and the structures of natural product pimprinine and streptochlorin, two series of novel pimprinine derivatives... 相似文献
4.
5.
Xue Jinming Wang Bo Li Ziqiang Xie Zongbo Le Zhanggao 《Research on Chemical Intermediates》2022,48(1):49-65
Research on Chemical Intermediates - In the process of uranium mining and smelting, large quantities of low-concentration uranium-containing wastewater have been produced. It is an ideal solution... 相似文献
6.
Mengyuan Zhang Peiling Lin Xiaofan Song Kun Chen Yuxuan Yang Yongliang Xu Qiang Zhang Youshen Wu Yanfeng Zhang Yilong Cheng 《Journal of polymer science. Part A, Polymer chemistry》2022,60(9):1511-1520
The design of wound dressings with excellent self-healing ability, adequate adhesion, good biocompatibility, and potential antibacterial ability is of great significance for the healing of infected wounds arising from human activities. Herein, a series of multi-functional hydrogel dressings, poly(ionized isocyanoethyl methacrylate-glutamine)/poly(hexamethylene guanidine) (iGx/PHMGy) hydrogels, were obtained through homopolymerization of fully ionized isocyanoethyl methacrylate-glutamine (iIEM-Gln) in the presence of poly(hexamethylene guanidine) (PHMG), in which strong hydrogen bonds were formed among urea groups in the P (iIEM-Gln) chain to form a stable hydrogel network. The prepared iGx/PHMGy hydrogels exhibited adequate self-healing ability and tissue adhesion, which could be firmly adhered to the wound surface and remained intact during application. In addition, the presence of PHMG imparted good antibacterial activity to the hydrogels for the effective promotion of the wound healing in S. aureus infected skin wound on mice. Overall, this multi-functional hydrogel provides a facile and effective strategy for the design of infected wound dressings, and may show great potential in clinical applications. 相似文献
7.
Zhang Mingjie Song Yang Abdelkefi Abdessattar Yu Haiyan Wang Junlei 《Nonlinear dynamics》2022,108(3):1867-1884
Nonlinear Dynamics - Vortex-induced vibration (VIV) systems with stiffness nonlinearity have received increasing attention because the stiffness nonlinearity can broaden the effective flow velocity... 相似文献
8.
Tingrui Li Yilitabaier Julaiti Xiaopeng Wu Jie Han Dr. Jin Xie 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(71):e202202851
The gold-catalyzed ring-opening rearrangement of cyclopropenes affords an efficient route to either polysubstituted naphthols or aryl-substituted furans. Owing to the unique dichotomy of gold−carbenes, this protocol provides a switchable reaction selectivity between naphthols and furans enabled by the use of TFP−Au(MeCN)SbF6 (tri(2-furyl) phosphine) or PNP(AuNTf2)2 (bis(diphenylphosphino)(isopropyl) amine) as catalysts respectively. It is proposed that the gold−carbene intermediate might be involved in the cyclopropene→naphthol rearrangement while the gold-carbocation is more likely to be involved in the cyclopropene→furan rearrangement. 相似文献
9.
Liu Wenbin Huang Yiwei Huang Guolin Fan Lijiao Xie Yuming Shi Jeffery 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2055-2068
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
10.