全文获取类型
收费全文 | 113659篇 |
免费 | 29338篇 |
国内免费 | 21811篇 |
专业分类
化学 | 75925篇 |
晶体学 | 1404篇 |
力学 | 7210篇 |
综合类 | 471篇 |
数学 | 14063篇 |
物理学 | 65735篇 |
出版年
2023年 | 1459篇 |
2022年 | 1542篇 |
2021年 | 1903篇 |
2020年 | 2505篇 |
2019年 | 2992篇 |
2018年 | 2769篇 |
2017年 | 3250篇 |
2016年 | 4034篇 |
2015年 | 4275篇 |
2014年 | 4450篇 |
2013年 | 6920篇 |
2012年 | 7734篇 |
2011年 | 9235篇 |
2010年 | 11595篇 |
2009年 | 11685篇 |
2008年 | 5844篇 |
2007年 | 5152篇 |
2006年 | 4698篇 |
2005年 | 4804篇 |
2004年 | 5154篇 |
2003年 | 4227篇 |
2002年 | 4052篇 |
2001年 | 4067篇 |
2000年 | 3159篇 |
1999年 | 3395篇 |
1998年 | 2766篇 |
1997年 | 2589篇 |
1996年 | 2851篇 |
1995年 | 3184篇 |
1994年 | 3185篇 |
1993年 | 3181篇 |
1992年 | 2671篇 |
1991年 | 2293篇 |
1990年 | 1979篇 |
1989年 | 2007篇 |
1988年 | 1938篇 |
1987年 | 1211篇 |
1986年 | 1290篇 |
1985年 | 949篇 |
1984年 | 1022篇 |
1982年 | 931篇 |
1981年 | 767篇 |
1980年 | 796篇 |
1979年 | 539篇 |
1978年 | 552篇 |
1977年 | 648篇 |
1976年 | 1054篇 |
1973年 | 449篇 |
1972年 | 537篇 |
1971年 | 436篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
21.
22.
JPC – Journal of Planar Chromatography – Modern TLC - A new high-performance thin-layer chromatographic (HPTLC) method has been developed for the simultaneous estimation of... 相似文献
23.
Tianyu Gong Longhai Guo Jun Ye Lifan He Teng Qiu Xiaoyu Li 《Journal of polymer science. Part A, Polymer chemistry》2021,59(16):1807-1820
The implementation of covalent adaptable networks (CANs) in general resin system is becoming attractive. In this work, we propose a simple post-curing strategy based on the core-shell structured acrylate latex for the achievement on both the improved general performance and the CANs characteristics in latex films. The building to the CANs was relied on the introduction of 4,4′-diaminophenyl disulfide as the curing agent, which cured the acetoacetoxy decorated shell polymer through the ketoamine reaction. The metathesis reaction of aromatic disulfides in the crosslinking segments enabled the thermally induced dynamic behavior of the network as revealed in the stress relaxation tests by comparison with other diamine crosslinking agents without the incorporation of disulfide. The synergism of the dynamic crosslinking of the shell polymer and static crosslinking in the core polymer contributed to the improved mechanical strength (15 MPa, strain% = 250%) and the suppressed water adsorption (~1% in 24 h of soaking) of the latex film, which exhibited above 90% of recovery in both strength and strain from a cut-off film damage within 1 h at 80°C. Moreover, the cured latex film could be recycled, and 75% of the mechanical performance was regained after three fragmentation-hot-pressing cycles. These, in addition with the feasible and environmental friendly characteristics, suggest a sustainable paradigm toward the smart thermosetting latex polymers. 相似文献
24.
Yuwei Wang Jia-Jun Yan Shengnan Hu Prof. David James Young Prof. Hong-Xi Li Prof. Zhi-Gang Ren 《化学:亚洲杂志》2021,16(18):2681-2686
A photoluminescent bimetallic cluster [Ag10Cu6(bdppthi)2(C≡CPh)12(MeOH)2(H2O)](ClO4)4 ( 1 , bdppthi=N,N’-bis(diphenylphosphanylmethyl)-tetrahydroimidazole} was synthesized from the PNNP type ligand bdppthi generated in-situ. Upon excitation at 365 nm, 1 exhibited strong phosphorescent emission at 630 nm, which was selectively quenched by NH3 in air or water. The sensing of NH3 was rapid and recoverable, with detection limits of 53 ppm (v/v) in N2 and 21 μmol/L (0.36 ppm, w/w) for NH3 ⋅ H2O in water. Cluster 1 could potentially serve as a bifunctional chemical sensor for the efficient detection of ammonia in waste-gas and waste-water. 相似文献
25.
Vsevolod Khikhlovskyi Albert J. J. M. van Breemen Jasper J. Michels René A. J. Janssen Gerwin H. Gelinck Martijn Kemerink 《Journal of Polymer Science.Polymer Physics》2015,53(17):1231-1237
In many organic electronic devices functionality is achieved by blending two or more materials, typically polymers or molecules, with distinctly different optical or electrical properties in a single film. The local scale morphology of such blends is vital for the device performance. Here, a simple approach to study the full 3D morphology of phase‐separated blends, taking advantage of the possibility to selectively dissolve the different components is introduced. This method is applied in combination with AFM to investigate a blend of a semiconducting and ferroelectric polymer typically used as active layer in organic ferroelectric resistive switches. It is found that the blend consists of a ferroelectric matrix with three types of embedded semiconductor domains and a thin wetting layer at the bottom electrode. Statistical analysis of the obtained images excludes the presence of a fourth type of domains. The criteria for the applicability of the presented technique are discussed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1231–1237 相似文献
26.
27.
28.
29.
30.
CongZhan Liu YiFei Zhang XuFang Li XueFeng Lu Zhi Chang ZhengWei Li AiMei Zhang YongJie Jin HuiMing Yu Zhao Zhang MinXue Fu YiBao Chen JianFeng Ji YuPeng Xu JingKang Deng RenCheng Shang GuoQing Liu FangJun Lu ShuangNan Zhang YongWei Dong TiPei Li Mei Wu YanGuo Li HuanYu Wang BoBing Wu YongJie Zhang Zhi Zhang ShaoLin Xiong Yuan Liu Shu Zhang HongWei Liu YiJung Yang Fan Zhang 《中国科学:物理学 力学 天文学(英文版)》2020,(4):20-34
The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments. 相似文献