全文获取类型
收费全文 | 71987篇 |
免费 | 18656篇 |
国内免费 | 4029篇 |
出版年
2024年 | 91篇 |
2023年 | 581篇 |
2022年 | 1524篇 |
2021年 | 2900篇 |
2020年 | 3769篇 |
2019年 | 5593篇 |
2018年 | 5583篇 |
2017年 | 5394篇 |
2016年 | 5949篇 |
2015年 | 6699篇 |
2014年 | 6871篇 |
2013年 | 7543篇 |
2012年 | 6069篇 |
2011年 | 5253篇 |
2010年 | 5255篇 |
2009年 | 3780篇 |
2008年 | 3074篇 |
2007年 | 2365篇 |
2006年 | 2088篇 |
2005年 | 1918篇 |
2004年 | 1710篇 |
2003年 | 1467篇 |
2002年 | 1331篇 |
2001年 | 1206篇 |
2000年 | 1008篇 |
1999年 | 895篇 |
1998年 | 504篇 |
1997年 | 502篇 |
1996年 | 467篇 |
1995年 | 436篇 |
1994年 | 392篇 |
1993年 | 262篇 |
1992年 | 389篇 |
1991年 | 286篇 |
1990年 | 243篇 |
1989年 | 229篇 |
1988年 | 159篇 |
1987年 | 179篇 |
1986年 | 136篇 |
1985年 | 124篇 |
1984年 | 104篇 |
1983年 | 85篇 |
1982年 | 62篇 |
1981年 | 35篇 |
1980年 | 23篇 |
1979年 | 25篇 |
1977年 | 14篇 |
1976年 | 11篇 |
1973年 | 10篇 |
1972年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
Hong Duc Pham Terry Chien‐Jen Yang Sagar M. Jain Gregory J. Wilson Prashant Sonar 《Liver Transplantation》2020,10(13)
There has been considerable progress over the last decade in development of the perovskite solar cells (PSCs), with reported performances now surpassing 25.2% power conversion efficiency. Both long‐term stability and component costs of PSCs remain to be addressed by the research community, using hole transporting materials (HTMs) such as 2,2′,7,7′‐tetrakis(N,N′‐di‐pmethoxyphenylamino)‐9,9′‐spirbiuorene(Spiro‐OMeTAD) and poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA). HTMs are essential for high‐performance PSC devices. Although effective, these materials require a relatively high degree of doping with additives to improve charge mobility and interlayer/substrate compatibility, introducing doping‐induced stability issues with these HTMs, and further, additional costs and experimental complexity associated with using these doped materials. This article reviews dopant‐free organic HTMs for PSCs, outlining reports of structures with promising properties toward achieving low‐cost, effective, and scalable materials for devices with long‐term stability. It summarizes recent literature reports on non‐doped, alternative, and more stable HTMs used in PSCs as essential components for high‐efficiency cells, categorizing HTMs as reported for different PSC architectures in addition to use of dopant‐free small molecular and polymeric HTMs. Finally, an outlook and critical assessment of dopant‐free organic HTMs toward commercial application and insight into the development of stable PSC devices is provided. 相似文献
982.
Bing‐Qing Xiong Xinwei Zhou Gui‐Liang Xu Yuzi Liu Likun Zhu Youcheng Hu Shou‐Yu Shen Yu‐Hao Hong Si‐Cheng Wan Xiao‐Chen Liu Xiang Liu Shengli Chen Ling Huang Shi‐Gang Sun Khalil Amine Fu‐Sheng Ke 《Liver Transplantation》2020,10(4)
Alloy materials such as Si and Ge are attractive as high‐capacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during discharge–charge processes. Compared to the over‐emphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solid‐electrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloy‐based anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li3Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiF‐dominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sb‐coated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh g?1 after 200 cycles at 500 mA g?1, compared to only 72% and 170 mAh g?1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve long‐term cycling stability for alloy‐based anode materials. 相似文献
983.
Yilin Wang Xiaohui Wang Baojun Lin Zhaozhao Bi Xiaobo Zhou Hafiz Bilal Naveed Ke Zhou Hongping Yan Zheng Tang Wei Ma 《Liver Transplantation》2020,10(28)
Sequential deposition has great potential to achieve high performance in organic solar cells due to the resulting well‐controlled vertical phase separation. In this work, double bulk heterojunction organic solar cells are fabricated by sequential‐blade cast in ambient conditions. Probed by the in situ grazing incidence X‐ray diffraction and in situ UV–vis absorption measurements, the seq‐blade system exhibits a different tendency from each of the binary films during the film formation process. Due to the extensive aggregation of FOIC, the binary PBDB‐T:FOIC film displays a strong and large phase separation, resulting in low current density (Jsc) and unsatisfactory power conversion efficiency. In the seq‐blade cast system, the bottom layer PBDB‐T:IT‐M produces many crystal nuclei for the top layer PBDB‐T:FOIC, so the PBDB‐T molecules are able to crystallize easily and quickly. Balanced crystallization kinetics between polymer and small molecule and an ideal percolation network in the film are observed. In addition, the balanced crystallization kinetics are favorable toward realizing lower recombination loss through charge transport processes. 相似文献
984.
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
985.
Energy Harvesting from Breeze Wind (0.7–6 m s−1) Using Ultra‐Stretchable Triboelectric Nanogenerator
Zewei Ren Ziming Wang Zhirong Liu Longfei Wang Hengyu Guo Linlin Li Site Li Xiangyu Chen Wei Tang Zhong Lin Wang 《Liver Transplantation》2020,10(36)
Wind is one of the most important sources of green energy, but the current technology for harvesting wind energy is only effective when the wind speed is beyond 3.5–4.0 m s?1. This is mainly due to the limitation that the electromagnetic generator works best at high frequency. This means that light breezes cannot reach the wind velocity threshold of current wind turbines. Here, a high‐performance triboelectric nanogenerator (TENG) for efficiently harvesting energy from an ambient gentle wind, especially for speeds below 3 m s?1 is reported, by taking advantage of the relative high efficiency of TENGs at low‐frequency. Attributed to the multiplied‐frequency vibration of ultra‐stretchable and perforated electrodes, an average output of 20 mW m?3 can be achieved with inlet wind speed of 0.7 m s?1, while an average energy conversion efficiency of 7.8% at wind speed of 2.5 m s?1 is reached. A self‐charging power package is developed and the applicability of the TENG in various light breezes is demonstrated. This work demonstrates the advantages of TENG technology for breeze energy exploitation and proposes an effective supplementary approach for current employed wind turbines and micro energy structure. 相似文献
986.
Byong‐June Lee Tong‐Hyun Kang Ha‐Young Lee Jitendra S. Samdani Yongju Jung Chunfei Zhang Zhou Yu Gui‐Liang Xu Lei Cheng Seoungwoo Byun Yong Min Lee Khalil Amine Jong‐Sung Yu 《Liver Transplantation》2020,10(22)
Despite their high theoretical energy density and low cost, lithium–sulfur batteries (LSBs) suffer from poor cycle life and low energy efficiency owing to the polysulfides shuttle and the electronic insulating nature of sulfur. Conductivity and polarity are two critical parameters for the search of optimal sulfur host materials. However, their role in immobilizing polysulfides and enhancing redox kinetics for long‐life LSBs are not fully understood. This work has conducted an evaluation on the role of polarity over conductivity by using a polar but nonconductive platelet ordered mesoporous silica (pOMS) and its replica platelet ordered mesoporous carbon (pOMC), which is conductive but nonpolar. It is found that the polar pOMS/S cathode with a sulfur mass fraction of 80 wt% demonstrates outstanding long‐term cycle stability for 2000 cycles even at a high current density of 2C. Furthermore, the pOMS/S cathode with a high sulfur loading of 6.5 mg cm?2 illustrates high areal and volumetric capacities with high capacity retention. Complementary physical and electrochemical probes clearly show that surface polarity and structure are more dominant factors for sulfur utilization efficiency and long‐life, while the conductivity can be compensated by the conductive agent involved as a required electrode material during electrode preparation. The present findings shed new light on the design principles of sulfur hosts towards long‐life and highly efficient LSBs. 相似文献
987.
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
988.
989.
990.
Bin Zhang Chong Luo Yaqian Deng Zhijia Huang Guangmin Zhou Wei Lv Yan‐Bing He Ying Wan Feiyu Kang Quan‐Hong Yang 《Liver Transplantation》2020,10(15)
The lithium–sulfur (Li–S) battery is a next generation high energy density battery, but its practical application is hindered by the poor cycling stability derived from the severe shuttling of lithium polysulfides (LiPSs). Catalysis is a promising way to solve this problem, but the rational design of relevant catalysts is still hard to achieve. This paper reports the WS2–WO3 heterostructures prepared by in situ sulfurization of WO3, and by controlling the sulfurization degree, the structure is controlled, which balances the trapping ability (by WO3) and catalytic activity (by WS2) toward LiPSs. As a result, the WS2–WO3 heterostructures effectively accelerate LiPS conversion and improve sulfur utilization. The Li–S battery with 5 wt% WS2–WO3 heterostructures as additives in the cathode shows an excellent rate performance and good cycling stability, revealing a 0.06% capacity decay each cycle over 500 cycles at 0.5 C. By building an interlayer with such heterostructure‐added graphenes, the battery with a high sulfur loading of 5 mg cm?2 still shows a high capacity retention of 86.1% after 300 cycles at 0.5 C. This work provides a rational way to prepare the metal oxide–sulfide heterostructures with an optimized structure to enhance the performance of Li–S batteries. 相似文献