全文获取类型
收费全文 | 23441篇 |
免费 | 2200篇 |
国内免费 | 1778篇 |
出版年
2023年 | 232篇 |
2022年 | 602篇 |
2021年 | 1040篇 |
2020年 | 738篇 |
2019年 | 852篇 |
2018年 | 894篇 |
2017年 | 677篇 |
2016年 | 880篇 |
2015年 | 1404篇 |
2014年 | 1541篇 |
2013年 | 1651篇 |
2012年 | 1972篇 |
2011年 | 1879篇 |
2010年 | 1233篇 |
2009年 | 1074篇 |
2008年 | 1189篇 |
2007年 | 1126篇 |
2006年 | 984篇 |
2005年 | 888篇 |
2004年 | 853篇 |
2003年 | 775篇 |
2002年 | 733篇 |
2001年 | 559篇 |
2000年 | 503篇 |
1999年 | 462篇 |
1998年 | 219篇 |
1997年 | 201篇 |
1996年 | 186篇 |
1995年 | 137篇 |
1994年 | 173篇 |
1993年 | 98篇 |
1992年 | 176篇 |
1991年 | 162篇 |
1990年 | 133篇 |
1989年 | 105篇 |
1988年 | 95篇 |
1987年 | 101篇 |
1986年 | 88篇 |
1985年 | 99篇 |
1984年 | 49篇 |
1983年 | 53篇 |
1982年 | 51篇 |
1981年 | 38篇 |
1980年 | 40篇 |
1979年 | 57篇 |
1978年 | 47篇 |
1977年 | 49篇 |
1975年 | 39篇 |
1974年 | 48篇 |
1973年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Dongwei Li Kang Liang Wenlong Cheng Changming Li Dongyuan Zhao Biao Kong 《Liver Transplantation》2019,9(21)
Freestanding layered membrane–based devices have broad applications in highly efficient energy‐storage/conversion systems. The liquid–solid interface is considered as a unique yet versatile interface for constructing such layered membrane–based devices. In this review, the authors outline recent developments in the fabrication of soft materials to functionalize layered devices from the aspect of liquid–solid interfacial assembly and engineering arts. Seven liquid–solid interfacial assembly strategies, including flow‐directed, superlattice, solvent‐casting, evaporation‐induced, dip‐coating, spinning, and electrospinning assemblies, are comprehensively highlighted with a focus on their synthetic pathways, formation mechanisms, and interface engineering strategies. Meanwhile, recent representative works on layered membrane–based devices for electrochemical energy applications are presented. Finally, challenges and opportunities of this research area are highlighted in order to stimulate future developments. This review not only offers comprehensive and practical approaches to assemble liquid–solid interfaces with soft materials for various important layered electrochemical energy devices but also sheds lights on fundamental insights by thoughtful discussions on performance enhancement mechanisms of these electrochemical energy systems. 相似文献
962.
963.
Caveolin-1 promotes Rfng expression via Erk-Jnk-p38 signaling pathway in mouse hepatocarcinoma cells
Zhang Cheng Wu Qiong Huang Huang Chen Xixi Huang Tianmiao Li Wenli Liu Yubo Zhang Jianing 《Journal of physiology and biochemistry》2019,75(4):549-559
Journal of Physiology and Biochemistry - Caveolin-1 (Cav-1) is a critical structural protein of caveolae and plays an oncogene-like role by participating in abnormal protein glycosylation in... 相似文献
964.
965.
Xiao Haibing Li Zhongwu Deng Chuxiong Liu Lin Chen Jia Huang Bin Nie Xiaodong Liu Chun Wang Danyang Jiang Jieyu 《Ecosystems》2019,22(8):1754-1766
Ecosystems - Vegetation restoration can dramatically affect soil carbon (C), nitrogen (N) pools and microbial communities. Yet, it is uncertain what effects of vegetation restoration have on... 相似文献
966.
Kai Cheng Shiyu Li Xiao Lv Yongbin Tian Haiyan Kong Xufeng Huang Yajun Duan Jihong Han Zhouling Xie Chenzhong Liao 《Bioorganic & medicinal chemistry letters》2019,29(8):1012-1018
Herein we report our efforts of developing reversible selective hMAO-B inhibitors based on isatin, a fragment in an X-ray crystal structure. Five different scaffolds were designed and many compounds were synthesized. Among them, compound A3 demonstrated very high potency and isoform selectivity against hMAO-B, 11 and 13 times more potent (IC50?=?3?nM) and 23.64 and 6.8 times more selective than the marked drugs, selegiline and safinamide. However, the endeavors to modify the polar 3-one group of isatin, that is in a hydrophobic environment in the binding site of hMAO-B, to small nonpolar hydrophobic groups did not bring about improved hMAO-B inhibitors, which may challenge our understanding of molecular interactions and molecular recognition in biological systems. 相似文献
967.
968.
Jianbin Wang Menghua Wu Chun Gao Hongzheng Fu 《Bioorganic & medicinal chemistry》2019,27(7):1320-1326
Kirenol is one of the biologically active diterpenoids from Siegesbeckia pubescens. In terms of the high content and typical structure, many ent-diterpenoids separated from S. pubescens were presumed to be biologically related to kirenol. Among them, epoxy-pimarane diterpenoids are belonging to a special family of naturally occurring compounds that attracted our attentions on their putative biosynthesis pathway and biological activities. Here, we designed and synthesized two known 14,16-epoxy-pimarane diterpenoids (2 and 3) and five 8,15-epoxy-pimarane diterpenoids (4–8) from kirenol. Their absolute structures were determined by 1D and 2D NMR data and the absolute configurations of 4 were confirmed by X-ray crystallographic data. Their inhibition effects on factor Xa (FXa) were evaluated to assess the potentiality of epoxy-pimarane diterpenoids as FXa inhibitor agents. 相似文献
969.
970.
Kang Li Dehong Wang Liang Gong Yuanyuan Lyu Hao Guo Wei Chen Cheng Jin Xianqing Liu Chuanying Fang Jie Luo 《The Plant journal : for cell and molecular biology》2019,100(5):908-922
Plants are considered an important food and nutrition source for humans. Despite advances in plant seed metabolomics, knowledge about the genetic and molecular bases of rice seed metabolomes at different developmental stages is still limited. Here, using Zhenshan 97 (ZS97) and Minghui 63 (MH63), we performed a widely targeted metabolic profiling in seeds during grain filling, mature seeds and germinating seeds. The diversity between MH63 and ZS97 was characterized in terms of the content of metabolites and the metabolic shifting across developmental stages. Taking advantage of the ultra‐high‐density genetic map of a population of 210 recombinant inbred lines (RILs) derived from a cross between ZS97 and MH63, we identified 4681 putative metabolic quantitative trait loci (mQTLs) in seeds across the three stages. Further analysis of the mQTLs for the codetected metabolites across the three stages revealed that the genetic regulation of metabolite accumulation was closely related to developmental stage. Using in silico analyses, we characterized 35 candidate genes responsible for 30 structurally identified or annotated compounds, among which LOC_Os07g04970 and LOC_Os06g03990 were identified to be responsible for feruloylserotonin and l ‐asparagine content variation across populations, respectively. Metabolite?agronomic trait association and colocation between mQTLs and phenotypic quantitative trait loci (pQTLs) revealed the complexity of the metabolite?agronomic trait relationship and the corresponding genetic basis. 相似文献