全文获取类型
收费全文 | 6275篇 |
免费 | 553篇 |
国内免费 | 12篇 |
专业分类
6840篇 |
出版年
2024年 | 7篇 |
2023年 | 65篇 |
2022年 | 128篇 |
2021年 | 220篇 |
2020年 | 99篇 |
2019年 | 161篇 |
2018年 | 178篇 |
2017年 | 173篇 |
2016年 | 224篇 |
2015年 | 326篇 |
2014年 | 321篇 |
2013年 | 413篇 |
2012年 | 503篇 |
2011年 | 458篇 |
2010年 | 290篇 |
2009年 | 224篇 |
2008年 | 321篇 |
2007年 | 325篇 |
2006年 | 277篇 |
2005年 | 272篇 |
2004年 | 204篇 |
2003年 | 183篇 |
2002年 | 221篇 |
2001年 | 147篇 |
2000年 | 190篇 |
1999年 | 129篇 |
1998年 | 50篇 |
1997年 | 28篇 |
1996年 | 33篇 |
1995年 | 46篇 |
1994年 | 34篇 |
1993年 | 32篇 |
1992年 | 68篇 |
1991年 | 58篇 |
1990年 | 58篇 |
1989年 | 58篇 |
1988年 | 44篇 |
1987年 | 33篇 |
1986年 | 41篇 |
1985年 | 44篇 |
1984年 | 25篇 |
1983年 | 21篇 |
1982年 | 12篇 |
1981年 | 16篇 |
1980年 | 8篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 7篇 |
1972年 | 6篇 |
排序方式: 共有6840条查询结果,搜索用时 15 毫秒
81.
Gihoon Cha Shiva Mohajernia Nhat Truong Nguyen Anca Mazare Nikita Denisov Imgon Hwang Patrik Schmuki 《Liver Transplantation》2020,10(6)
Recently, sodium ion batteries (SIBs) have been widely investigated as one of the most promising candidates for replacing lithium ion batteries (LIBs). For SIBs or LIBs, designing a stable and uniform solid electrolyte interphase (SEI) at the electrode–electrolyte interface is the key factor to provide high capacity, long‐term cycling, and high‐rate performance. In this paper, it is described how a remarkably enhanced SEI layer can be obtained on TiO2 nanotube (TiO2 NTs) arrays that allows for a strongly improved performance of sodium battery systems. Key is that a Li+ pre‐insertion in TiO2 NTs can condition the SEI for Na+ replacement. SIBs constructed with Li‐pre‐inserted NTs deliver an exceptional Na+ cycling stability (e.g., 99.9 ± 0.1% capacity retention during 250 cycles at a current rate of 50 mA g?1) and an excellent rate capability (e.g., 132 mA h g?1 at a current rate of 1 A g?1). The key factor in this outstanding performance is that Li‐pre‐insertion into TiO2 NTs leads not only to an enhanced electronic conductivity in the tubes, but also expands the anatase lattice for facilitated subsequent Na+ cycling. 相似文献
82.
Akchheta Karki Joachim Vollbrecht Alexander J. Gillett Philipp Selter Jaewon Lee Zhengxing Peng Nora Schopp Alana L. Dixon Max Schrock Vojtech Ndady Franz Schauer Harald Ade Bradley F. Chmelka Guillermo C. Bazan Richard H. Friend Thuc‐Quyen Nguyen 《Liver Transplantation》2020,10(29)
Even though significant breakthroughs with over 18% power conversion efficiencies (PCEs) in polymer:non‐fullerene acceptor (NFA) bulk heterojunction organic solar cells (OSCs) have been achieved, not many studies have focused on acquiring a comprehensive understanding of the underlying mechanisms governing these systems. This is because it can be challenging to delineate device photophysics in polymer:NFA blends comprehensively, and even more complicated to trace the origins of the differences in device photophysics to the subtle differences in energetics and morphology. Here, a systematic study of a series of polymer:NFA blends is conducted to unify and correlate the cumulative effects of i) voltage losses, ii) charge generation efficiencies, iii) non‐geminate recombination and extraction dynamics, and iv) nuanced morphological differences with device performances. Most importantly, a deconvolution of the major loss processes in polymer:NFA blends and their connections to the complex BHJ morphology and energetics are established. An extension to advanced morphological techniques, such as solid‐state NMR (for atomic level insights on the local ordering and donor:acceptor π? π interactions) and resonant soft X‐ray scattering (for donor and acceptor interfacial area and domain spacings), provide detailed insights on how efficient charge generation, transport, and extraction processes can outweigh increased voltage losses to yield high PCEs. 相似文献
83.
84.
Dung Quang Nguyen Dominik Schneider Nicole Brinkmann Bin Song Dennis Janz Ingo Schöning Rolf Daniel Rodica Pena Andrea Polle 《Environmental microbiology》2020,22(8):3081-3095
Root-associated fungi (RAF) link nutrient fluxes between soil and roots and thus play important roles in ecosystem functioning. To enhance our understanding of the factors that control RAF, we fitted statistical models to explain variation in RAF community structure using data from 150 temperate forest sites covering a broad range of environmental conditions and chemical root traits. We found that variation in RAF communities was related to both root traits (e.g., cations, carbohydrates, NO3−) and soil properties (pH, cations, moisture, C/N). The identified drivers were the combined result of distinct response patterns of fungal taxa (determined at the rank of orders) to biotic and abiotic factors. Our results support that RAF community variation is related to evolutionary adaptedness of fungal lineages and consequently, drivers of RAF communities are context-dependent. 相似文献
85.
86.
A new temperate wood bamboo endemic to Vietnam is described and illustrated as Chimonocalamus bidoupensis N.H.Nghia & V.T.Tran. The new species is similar to C. baviensis in general appearance, but differs by its densely ciliate culms, culm sheaths that are concave at the apex with dense, white hairs on the abaxial surface of the sheath, and perfect florets 7–8 mm long. 相似文献
87.
88.
Chen Yizhou Nguyen Duong T. Gupta Risha Herron Grant A. 《Molecular biology reports》2021,48(4):3155-3163
Molecular Biology Reports - Western flower thrips, Frankliniella occidentalis is an economically important agricultural pest. It causes damage by feeding and oviposition or indirectly by plant... 相似文献
89.
90.