全文获取类型
收费全文 | 49590篇 |
免费 | 17667篇 |
国内免费 | 434篇 |
专业分类
67691篇 |
出版年
2023年 | 97篇 |
2022年 | 154篇 |
2021年 | 615篇 |
2020年 | 2921篇 |
2019年 | 4480篇 |
2018年 | 4771篇 |
2017年 | 4714篇 |
2016年 | 4410篇 |
2015年 | 4274篇 |
2014年 | 4340篇 |
2013年 | 4867篇 |
2012年 | 4042篇 |
2011年 | 4230篇 |
2010年 | 3692篇 |
2009年 | 2586篇 |
2008年 | 2774篇 |
2007年 | 2191篇 |
2006年 | 2193篇 |
2005年 | 1826篇 |
2004年 | 1480篇 |
2003年 | 1577篇 |
2002年 | 1363篇 |
2001年 | 1003篇 |
2000年 | 544篇 |
1999年 | 404篇 |
1998年 | 134篇 |
1997年 | 130篇 |
1996年 | 100篇 |
1995年 | 145篇 |
1994年 | 146篇 |
1993年 | 125篇 |
1992年 | 133篇 |
1991年 | 82篇 |
1990年 | 98篇 |
1989年 | 66篇 |
1988年 | 47篇 |
1987年 | 57篇 |
1986年 | 44篇 |
1985年 | 86篇 |
1984年 | 125篇 |
1983年 | 101篇 |
1982年 | 127篇 |
1981年 | 83篇 |
1980年 | 59篇 |
1979年 | 62篇 |
1978年 | 34篇 |
1977年 | 47篇 |
1976年 | 30篇 |
1975年 | 36篇 |
1973年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
Xinliang Li Mian Li Qi Yang Guojin Liang Zhaodong Huang Longtao Ma Donghong Wang Funian Mo Binbin Dong Qing Huang Chunyi Zhi 《Liver Transplantation》2020,10(36)
The traditional method to fabricate a MXene based energy storage device starts from etching MAX phase particles with dangerous acid/alkali etchants to MXenes, followed by device assembly. This is a multistep protocol and is not environmentally friendly. Herein, an all‐in‐one protocol is proposed to integrate synthesis and battery fabrication of MXene. By choosing a special F‐rich electrolyte, MAX V2AlC is directly exfoliated inside a battery and the obtained V2CTX MXene is in situ used to achieve an excellent battery performance. This is a one‐step process with all reactions inside the cell, avoiding any contamination to external environments. Through the lifetime, the device experiences three stages of exfoliation, electrode oxidation, and redox of V2O5. While the electrode is changing, the device can always be used as a battery and the performance is continuously enhanced. The resulting aqueous zinc ion battery achieves outstanding cycling stability (4000 cycles) and rate performance (97.5 mAh g?1 at 64 A g?1), distinct from all reported aqueous MXene‐based counterparts with pseudo‐capacitive properties, and outperforming most vanadium‐based zinc ion batteries with high capacity. This work sheds light on the green synthesis of MXenes, provides an all‐in‐one protocol for MXene devices, and extends MXenes’ application in the aqueous energy storage field. 相似文献
982.
Utilizing redox‐active organic compounds for future energy storage system (ESS) has attracted great attention owing to potential cost efficiency and environmental sustainability. Beyond enriching the pool of organic electrode materials with molecular tailoring, recent scientific efforts demonstrate the innovations in various cell chemistries and configurations. Herein, recent major strategies to build better organic batteries, are highlighted: diversifying charge‐carrying ions, modifying electrolytes, and utilizing liquid‐type organic electrodes. Each approach is summarized along with their advantages over Li‐ion batteries (LIBs). An outlook is also provided on the practical realization of organic battery systems, which hints at possible solutions for future sustainable ESSs. 相似文献
983.
Xiaohui Zeng Jiatu Liu Jianfeng Mao Junnan Hao Zhijie Wang Si Zhou Chris D. Ling Zaiping Guo 《Liver Transplantation》2020,10(32)
Rechargeable aqueous Zn/MnO2 batteries are very attractive large‐scale energy storage technologies, but still suffer from limited cycle life and low capacity. Here the novel adoption of a near‐neutral acetate‐based electrolyte (pH ≈ 6) is presented to promote the two‐electron Mn4+/Mn2+ redox reaction and simultaneously enable a stable Zn anode. The acetate anion triggers a highly reversible MnO2/Mn2+ reaction, which ensures high capacity and avoids the issue of structural collapse of MnO2. Meanwhile, the anode‐friendly electrolyte enables a dendrite‐free Zn anode with outstanding stability and high plating/stripping Coulombic efficiency (99.8%). Hence, a high capacity of 556 mA h g?1, a lifetime of 4000 cycles without decay, and excellent rate capability up to 70 mA cm?2 are demonstated in this new near‐neutral aqueous Zn/MnO2 battery by simply manipulating the salt anion in the electrolyte. The acetate anion not only modifies the surface properties of MnO2 cathode but also creates a highly compatible environment for the Zn anode. This work provides a new opportunity for developing high‐performance Zn/MnO2 and other aqueous batteries based on the salt anion chemistry. 相似文献
984.
Hoon‐Hee Ryu Nam‐Yung Park Dae Ro Yoon Un‐Hyuck Kim Chong S. Yoon Yang‐Kook Sun 《Liver Transplantation》2020,10(25)
A new class of layered cathodes, Li[NixCoyB1?x?y]O2 (NCB), is synthesized. The proposed NCB cathodes have a unique microstructure in which elongated primary particles are tightly packed into spherical secondary particles. The cathodes also exhibit a strong crystallographic texture in which the a–b layer planes are aligned along the radial direction, facilitating Li migration. The microstructure, which effectively suppresses the formation of microcracks, improves the cycling stability of the NCB cathodes. The NCB cathode with 1.5 mol% B delivers a discharge capacity of 234 mAh g?1 at 0.1 C and retains 91.2% of its initial capacity after 100 cycles (compared to values of 229 mAh g?1 at 0.1 C and 78.8% for pristine Li[Ni0.9Co0.1]O2). This study shows the importance of controlling the microstructure to obtain the required cycling stability, especially for Ni‐rich layered cathodes, where the main cause of capacity fading is related to mechanical strain in their charged state. 相似文献
985.
986.
987.
Jin Zhao Yi‐Zhou Zhang Jianyu Chen Wenli Zhang Du Yuan Rodney Chua Husam N. Alshareef Yanwen Ma 《Liver Transplantation》2020,10(18)
The pursuit of more efficient carbon‐based anodes for sodium‐ion batteries (SIBs) prepared from facile and economical methods is a very important endeavor. Based on the crystallinity difference within carbon materials, herein, a low‐temperature selective burning method is developed for preparing oxygen and nitrogen codoped holey graphene aerogel as additive‐free anode for SIBs. By selective burning of a mixture of graphene and low‐crystallinity carbon at 450 °C in air, an elastic porous graphene monolith with abundant holes on graphene sheets and optimized crystallinity is obtained. These structural characteristics lead to an additive‐free electrode with fast charge (ions and electrons) transfer and more abundant Na+ storage active sites. Moreover, the heteroatom oxygen/nitrogen doping favors large interlayer distance for rapid Na+ insertion/extraction and provides more active sites for high capacitive contribution. The optimized sample exhibits superior sodium‐ion storage capability, i.e., high specific capacity (446 mAh g?1 at 0.1 A g?1), ultrahigh rate capability (189 mAh g?1 at 10 A g?1), and long cycle life (81.0% capacity retention after 2000 cycles at 5 A g?1). This facile and economic strategy might be extended to fabricating other superior carbon‐based energy storage materials. 相似文献
988.
Changjian Zuo Zongxiang Hu Rui Qi Jiajie Liu Zhibo Li Junliang Lu Cheng Dong Kai Yang Weiyuan Huang Cong Chen Zhibo Song Sicheng Song Yaoming Yu Jiaxin Zheng Feng Pan 《Liver Transplantation》2020,10(34)
The relatively low capacity and capacity fade of spinel LiMn2O4 (LMO) limit its application as a cathode material for lithium‐ion batteries. Extending the potential window of LMO below 3 V to access double capacity would be fantastic but hard to be realized, as it will lead to fast capacity loss due to the serious Jahn–Teller distortion. Here using experiments combined with extensive ab initio calculations, it is proved that there is a cooperative effect among individual Jahn–Teller distortions of Mn3+O6 octahedrons in LMO, named as cooperative Jahn–Teller distortion (CJTD) in the text, which is the difficulty to access the capacity beyond one lithium intercalation. It is further proposed that the cationic disordering (excess Li at Mn sites and Li/Mn exchange) can intrinsically suppress the CJTD of Mn3+O6 octahedrons. The cationic disordering can break the symmetry of Mn3+ arrangements to disrupt the correlation of distortions arising from individual JT centers and prevent the Mn3+? O bonds distorting along one direction. Interestingly, with the suppressed CJTD, the original octahedral vacancies in spinel LMO are activated and can serve as extra Li‐ion storage sites to access the double capacity with good reversible cycling stability in microsized LMO. 相似文献
989.
Energy generation and consumption have always been an important component of social development. Interests in this field are beginning to shift to indoor photovoltaics (IPV) which can serve as power sources under low light conditions to meet the energy needs of rapidly growing fields, such as intelligence gathering and information processing which usually operate via the Internet‐of‐things (IoT). Since the power requirements for this purpose continue to decrease, IPV systems under low light may facilitate the realization of self‐powered high‐tech electronic devices connected through the IoT. This review discusses and compares the characteristics of different types of IPV devices such as those based on silicon, dye, III‐V semiconductors, organic compounds, and halide perovskites. Among them, specific attention is paid to perovskite photovoltaics which may potentially become a high performing IPV system due to the fascinating photophysics of the halide perovskite active layer. The limitations of such indoor application as they relate to the toxicity, stability, and electronic structure of halide perovskites are also discussed. Finally, strategies which could produce highly functional, nontoxic, and stable perovskite photovoltaics devices for indoor applications are proposed. 相似文献