全文获取类型
收费全文 | 11710篇 |
免费 | 1531篇 |
国内免费 | 813篇 |
专业分类
化学 | 3402篇 |
晶体学 | 27篇 |
力学 | 237篇 |
综合类 | 45篇 |
数学 | 70篇 |
物理学 | 2624篇 |
无线电 | 7649篇 |
出版年
2024年 | 43篇 |
2023年 | 172篇 |
2022年 | 298篇 |
2021年 | 380篇 |
2020年 | 459篇 |
2019年 | 360篇 |
2018年 | 293篇 |
2017年 | 493篇 |
2016年 | 604篇 |
2015年 | 679篇 |
2014年 | 939篇 |
2013年 | 849篇 |
2012年 | 1063篇 |
2011年 | 886篇 |
2010年 | 678篇 |
2009年 | 746篇 |
2008年 | 786篇 |
2007年 | 840篇 |
2006年 | 632篇 |
2005年 | 452篇 |
2004年 | 435篇 |
2003年 | 354篇 |
2002年 | 270篇 |
2001年 | 195篇 |
2000年 | 176篇 |
1999年 | 159篇 |
1998年 | 157篇 |
1997年 | 146篇 |
1996年 | 97篇 |
1995年 | 90篇 |
1994年 | 70篇 |
1993年 | 69篇 |
1992年 | 59篇 |
1991年 | 38篇 |
1990年 | 31篇 |
1989年 | 20篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
21.
Quentin Coquerel Claire Legendre Jacinthe Frangieh Stephan De Waard Jrme Montnach Leos Cmarko Joseph Khoury Charifat Said Hassane Dimitri Brard Benjamin Siegler Ziad Fajloun Harold De Pomyers Kamel Mabrouk Norbert Weiss Daniel Henrion Pascal Richomme Csar Mattei Michel De Waard Anne-Marie Le Ray Christian Legros 《Molecules (Basel, Switzerland)》2022,27(13)
Voltage-gated Na+ (NaV) channels are significant therapeutic targets for the treatment of cardiac and neurological disorders, thus promoting the search for novel NaV channel ligands. With the objective of discovering new blockers of NaV channel ligands, we screened an In-House vegetal alkaloid library using fluorescence cell-based assays. We screened 62 isoquinoline alkaloids (IA) for their ability to decrease the FRET signal of voltage sensor probes (VSP), which were induced by the activation of NaV channels with batrachotoxin (BTX) in GH3b6 cells. This led to the selection of five IA: liriodenine, oxostephanine, thalmiculine, protopine, and bebeerine, inhibiting the BTX-induced VSP signal with micromolar IC50. These five alkaloids were then assayed using the Na+ fluorescent probe ANG-2 and the patch-clamp technique. Only oxostephanine and liriodenine were able to inhibit the BTX-induced ANG-2 signal in HEK293-hNaV1.3 cells. Indeed, liriodenine and oxostephanine decreased the effects of BTX on Na+ currents elicited by the hNaV1.3 channel, suggesting that conformation change induced by BTX binding could induce a bias in fluorescent assays. However, among the five IA selected in the VSP assay, only bebeerine exhibited strong inhibitory effects against Na+ currents elicited by the hNav1.2 and hNav1.6 channels, with IC50 values below 10 µM. So far, bebeerine is the first BBIQ to have been reported to block NaV channels, with promising therapeutical applications. 相似文献
22.
23.
24.
25.
Accurate node localization in wireless sensor networks (WSNs) is an essential for many networking protocols like clustering, routing, and network map building. The classical localization techniques such as multilateration and optimization‐based least square localization (OLSL) techniques estimate position of unknown node (UN) from the distance measured between all anchor nodes (ANs) and UNs. On the other hand, node localization using fixed terrestrial ANs suffers from poor localization accuracy because the ground to ground (GG) channel link is not reliable. By contrast, the mobile anchor deployed in unmanned aerial vehicle (UAV) provides high localization accuracy through reliable air to ground (AG) channel link. Still, the nonlinear distortion introduced in the wireless channel makes the distance measurement noisy. This noisy distance measurement also limits localization accuracy of classical localization techniques. Hence, the highly nonlinear artificial neural network (ANN) models such as multilayer perceptron (MLP) models can be applied effectively for node localization in UAV‐assisted WSNs. However, the MLP suffers from slow training speed, which limits its usage in real‐time applications. So, the extreme learning machine (ELM) is found to be a better alternative because it works on empirical error minimization theory, and its learning process requires only a single iteration. The detailed simulation analysis supports the proposed ELM localization scheme in terms of both localization accuracy and computational complexity. 相似文献
26.
27.
28.
Rui Li Xin Gou Xinyan Li Hainuo Wang Haibo Ruan Yuting Xiong Xianlun Tang Yuanyuan Li Ping-an Yang 《Molecules (Basel, Switzerland)》2022,27(15)
Flexible strain sensors, when considering high sensitivity and a large strain range, have become a key requirement for current robotic applications. However, it is still a thorny issue to take both factors into consideration at the same time. Here, we report a sandwich-structured strain sensor based on Fe nanowires (Fe NWs) that has a high GF (37–53) while taking into account a large strain range (15–57.5%), low hysteresis (2.45%), stability, and low cost with an areal density of Fe NWs of 4.4 mg/cm2. Additionally, the relationship between the contact point of the conductive network, the output resistance, and the areal density of the sensing unit is analyzed. Microscopically, the contact points of the conductive network directly affect the sensor output resistance distribution, thereby affecting the gauge factor (GF) of the sensor. Macroscopically, the areal density and the output resistivity of the strain sensor have the opposite percolation theory, which affects its linearity performance. At the same time, there is a positive correlation between the areal density and the contact point: when the stretching amount is constant, it theoretically shows that the areal density affects the GF. When the areal density reaches this percolation threshold range, the sensing performance is the best. This will lay the foundation for rapid applications in wearable robots. 相似文献
29.
30.