全文获取类型
收费全文 | 5891篇 |
免费 | 1434篇 |
国内免费 | 813篇 |
专业分类
化学 | 2250篇 |
晶体学 | 131篇 |
力学 | 68篇 |
综合类 | 20篇 |
数学 | 49篇 |
物理学 | 1607篇 |
无线电 | 4013篇 |
出版年
2024年 | 36篇 |
2023年 | 249篇 |
2022年 | 184篇 |
2021年 | 405篇 |
2020年 | 356篇 |
2019年 | 320篇 |
2018年 | 296篇 |
2017年 | 515篇 |
2016年 | 621篇 |
2015年 | 607篇 |
2014年 | 720篇 |
2013年 | 675篇 |
2012年 | 654篇 |
2011年 | 560篇 |
2010年 | 361篇 |
2009年 | 267篇 |
2008年 | 231篇 |
2007年 | 214篇 |
2006年 | 169篇 |
2005年 | 151篇 |
2004年 | 113篇 |
2003年 | 87篇 |
2002年 | 45篇 |
2001年 | 48篇 |
2000年 | 41篇 |
1999年 | 25篇 |
1998年 | 32篇 |
1997年 | 20篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 12篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有8138条查询结果,搜索用时 15 毫秒
991.
Soon Hyung Kang Jae-Yup Kim Hyun Sik Kim Haeng-Deog Koh Jae-Suk Lee Yung-Eun Sung 《Journal of photochemistry and photobiology. A, Chemistry》2008,200(2-3):294-300
A TiO2 film was modified by adding light scattering particles and applied to an anode electrode in solid-state dye-sensitized solar cells (DSSCs). The TiO2 films with 10 wt% (vs. TiO2 weight) light scattering particles showed enhanced performance (28%), compared with nanocrystalline TiO2 films, which were used as the controls. In particular, the photocurrent density (Jsc) reached approximately 12.6 mA/cm2 under a one-sun condition. This was attributed to the light scattering effect and decrease in internal resistance through the macroporous structure with a minor loss of electron transport. However, in the case of a larger concentration of light scattering particles (>10 wt%), there was a decrease in the efficiency of DSSCs, which resulted from the decreased surface area and degraded electron transport and charge recombination properties, as confirmed by the measurement of stepped light-induced photocurrent and photovoltage transients. Furthermore, the diffusion properties and kinetics of the composite polymer electrolyte with the nanoporous and macroporous TiO2 films were compared and evaluated from the electrochemical impedance spectra. 相似文献
992.
Fen Luo Liduo Wang Beibei Ma Yong Qiu 《Journal of photochemistry and photobiology. A, Chemistry》2008,197(2-3):375-381
In this study, dye-sensitized TiO2 electrodes were immersed into a solution of aluminum isopropoxide and after hydrolysis quasi-solid-state solar cells were fabricated. The interaction between the dye and the resulting Al2O3 overlayer was investigated by ultraviolet–visible (UV–vis) spectrum, Fourier transform infrared (FTIR) spectrum and X-ray photoelectron spectrum (XPS). The current density–voltage (I–V) characteristics showed that the overlayer increased the photovoltage and decreased the photocurrent under low intensity irradiation, and increased both the photovoltage and photocurrent under AM 1.5 irradiation. The Al2O3 overlayer at the dye/electrolyte interface resulted in a 28% improvement in overall photo-to-electrical conversion efficiency from 2.60 to 3.32%. Dark current measurements showed that Al2O3 acted as an insulator barrier to retard recombination between the TiO2 and dye/quasi-solid-state electrolyte interface. Without encapsulation, dye-sensitized solar cells with Al2O3 coating after sensitization also exhibited improved stability compared to cells without coating. 相似文献
993.
Jrme Fortage Marjorie Sverac Coralie Houarner-Rassin Yann Pellegrin Errol Blart Fabrice Odobel 《Journal of photochemistry and photobiology. A, Chemistry》2008,197(2-3):156-169
Eight novel perylene imide derivatives were synthesized to determine the effect of the nature of electron donating substituents on the perylene core (ether or N-amino), the position of the carboxylic acid anchoring group and the presence of a fused benzimidazole moiety on the performances of dye-sensitized solar cells. The photovoltaic efficiency under AM1.5 of these new dyes, although not optimized, ranges from 0.2% until 2.3%. We note the importance of the position-anchoring group, which controls the electron injection efficiency. With respect to the excited-state electron donor strength, four O-aryl substituents at the bay position lead to similar effect as two N-piperidinyl groups but with a lower propensity to aggregation and give slightly higher photovoltaic performance than the latter. The benzimidazole unit extends the absorbance of the perylene imide to longer wavelengths, but this effect is lower than introducing charge transfer transition with N-amino substituents. Overall, this work shows that perylene imide remains a promising molecular basis for the future design of new fully organic sensitizers for nanostructured TiO2 solar cells. 相似文献
994.
P. A. Troshin A. S. Peregudov S. I. Troyanov R. N. Lyubovskaya 《Russian Chemical Bulletin》2008,57(5):887-912
The results of the authors’ studies on the [2+3] cycloaddition of azomethine and nitrile ylides generated from picolylamine
and benzylamine derivatives to fullerenes are systematized and new experimental data are considered. Catalysts and microwave
radiation promoting the formation of ylides and their addition to fullerenes were successfully used for the first time. A
large series of new pyrrolidine and pyrroline derivatives of fullerenes C60 and C70 were synthesized and characterized. The proposed procedures afford the reaction products in yields twice as high (80–85%)
as those attained by the classical Prato reaction. The reactions proceed with virtually complete regio- (in the case of C70) and stereoselectivity to afford only cis-2′,5′-disubstituted and trans-1′,2′,5′-trisubstituted pyrrolidinofullerenes. Pyridyl-substituted pyrrolidinofullerenes react with metalloporphyrins and
phthalocyanines to form self-ordered coordination complexes. The latter are analogs of natural photosynthetic antenna systems
due to photoinduced charge separation that occurs in these complexes upon exposure to light.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 873–898, May, 2008. 相似文献
995.
设计合成了6个带有烷基链的D-π-A型有机光敏染料应用于染料敏化太阳能电池. 发现长链烷基有利于电池开路光电压的提高. 利用脂肪酸共敏化可进一步提高染料分子的敏化效果, 且提高的程度与脂肪酸的链长有重要关系. 相似文献
996.
Dr. Nimisha Jain Angelina Mary Tanu Singh Srushti Gadiyaram Dr. Jyoti Joshi Dr. D. Amilan Jose Dr. Abbas Raja Naziruddin 《欧洲无机化学杂志》2023,26(26):e202300210
We report heteroleptic ruthenium complexes of terpyridine (tpy) ligands with directly linked carboxylic acid anchors. These complexes feature methyl or methoxy-substituted 4′−Phtpy as donor ligands. We prepared these heteroleptic complexes from the ruthenium (II) precursor via a milder route to preclude the homoleptic complex formation. The donor−acceptor arrangement of tpy ligands in these ruthenium complexes renders visible light absorption giving metal and ligand-to-ligand charge transfer excitations at c.a. 490 nm. We evaluate the effect of the tpy donor substituents on the light-harvesting ability in Dye-Sensitized Solar Cells (DSSCs) and compare their photosensitizing ability with heteroleptic complexes bearing phenyl spacer at the acceptor end. Further, scrutinizing their photovoltaic performance, we studied their electron transfer kinetics in DSSCs using electrochemical impedance spectroscopy. This paper presents the structure-photosensitization relationship of these heteroleptic ruthenium complexes through a combined experimental and computational approach. 相似文献
997.
Dr. Ningxia Gu Zeyuan Sun Dr. Lixin Song Prof. Dr. Pingfan Du Prof. Dr. Jie Xiong 《Chemphyschem》2023,24(14):e202200919
The perovskite solar cells (PSCs) with high efficiency and stability are in great demand for commercial applications. Although the remarkable photovoltaic feature of perovskite layer plays a great role in improving the PCE of PSCs, the inevitable defects and poor stability of perovskite, etc. are the bottleneck and restrict the commercialization of PSCs. Herein, a review provides a strategy of applying aggregation-induced emission (AIE) molecules, containing passivation functional groups and distinct AIE character, which serves as the alternative materials for fabricating high-efficiency and high-stability PSCs. The methods of introducing AIE molecules to PSCs are also summarized, including additive engineering, interfacial engineering, hole transport materials and so on. In addition, the functions of AIE molecule are discussed, such as defects passivation, morphology modulation, well-matched energy level, enhanced stability, hole transport ability, carrier recombination suppression. Finally, the detailed functions of AIE molecules are offered and further research trend for high performance PSCs based on AIE materials is proposed. 相似文献
998.
Bingchu Tian Dr. Yanbo Shang Yi Tu Dr. Jun Hu Dr. Dong Han Qian Xu Prof. Shangfeng Yang Prof. Yifan Ye Dr. Honghe Ding Dr. Yu Li Prof. Junfa Zhu 《Chemphyschem》2023,24(20):e202300400
The interfacial electronic structure of perovskite layers and transport layers is critical for the performance and stability of perovskite solar cells (PSCs). The device performance of PSCs can generally be improved by adding a slight excess of lead iodide (PbI2) to the precursor solution. However, its underlying working mechanism is controversial. Here, we performed a comprehensive study of the electronic structures at the interface between CH3NH3PbI3 and C60 with and without the modification of PbI2 using in situ photoemission spectroscopy measurements. The correlation between the interfacial structures and the device performance was explored based on performance and stability tests. We found that there is an interfacial dipole reversal, and the downward band bending is larger at the CH3NH3PbI3/C60 interface with the modification of PbI2 as compared to that without PbI2. Therefore, PSCs with PbI2 modification exhibit faster charge carrier transport and slower carrier recombination. Nevertheless, the modification of PbI2 undermines the device stability due to aggravated iodide migration. Our findings provide a fundamental understanding of the CH3NH3PbI3/C60 interfacial structure from the perspective of the atomic layer and insight into the double-edged sword effect of PbI2 as an additive. 相似文献
999.
Dr. Aline Varella Rodrigues Bruno Seiki Domingos Onishi Prof. Dr. Sidney José Lima Ribeiro 《Chemphyschem》2023,24(21):e202300134
This research endeavors to overcome the significant challenge of developing materials that simultaneously possess photostability and photosensitivity to UV-visible irradiation. Sulfurized nanorod (NR)-like ZnO/Zn(OH)2 and hierarchical flower-like γ-Zn(OH)2/ϵ-Zn(OH)2 were identified from XRD diffraction patterns and Raman vibrational modes. The sulfurized material, observed by FEG-SEM and TEM, showed diameters ranging from 10 and 40 nm and lengths exceeding 200 nm. The S2− ions intercalated Zn2+, modulating NRs to dumbbell-like microrods. SAED and HRTEM illustrated the atomic structure in (101) crystal plane. Its direct band gap of 3.0 eV was attributed to the oxygen vacancies, which also contribute to the deep-level emissions at 422 and 485 nm. BET indicated specific surface area of 4.4 m2 g−1 and pore size as mesoporosity, which are higher compared to the non-sulfurized analogue. These findings were consistent with the observed photocurrent, photostability and photoluminescence (PL), further supporting the suitability of sulfurized NR-like ZnO/Zn(OH)2 as a promising candidate for Luminescent solar concentrators (LSC)-photovoltaic (PV) system. 相似文献
1000.
Junction Adhesion: Nanostructured Si/Organic Heterojunction Solar Cells with High Open‐Circuit Voltage via Improving Junction Quality (Adv. Funct. Mater. 28/2016)
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shan Wu Wei Cui Nabi Aghdassi Tao Song Steffen Duhm Shuit‐Tong Lee Baoquan Sun 《Advanced functional materials》2016,26(28):5192-5192