全文获取类型
收费全文 | 3345篇 |
免费 | 114篇 |
国内免费 | 7篇 |
专业分类
化学 | 2254篇 |
晶体学 | 49篇 |
力学 | 123篇 |
数学 | 340篇 |
物理学 | 700篇 |
出版年
2023年 | 24篇 |
2022年 | 64篇 |
2021年 | 72篇 |
2020年 | 72篇 |
2019年 | 63篇 |
2018年 | 58篇 |
2017年 | 56篇 |
2016年 | 120篇 |
2015年 | 93篇 |
2014年 | 140篇 |
2013年 | 203篇 |
2012年 | 292篇 |
2011年 | 273篇 |
2010年 | 183篇 |
2009年 | 155篇 |
2008年 | 222篇 |
2007年 | 213篇 |
2006年 | 192篇 |
2005年 | 143篇 |
2004年 | 135篇 |
2003年 | 107篇 |
2002年 | 111篇 |
2001年 | 57篇 |
2000年 | 56篇 |
1999年 | 24篇 |
1998年 | 19篇 |
1997年 | 14篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 15篇 |
1993年 | 21篇 |
1992年 | 12篇 |
1991年 | 15篇 |
1990年 | 18篇 |
1989年 | 19篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 16篇 |
1979年 | 12篇 |
1978年 | 16篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1974年 | 6篇 |
1973年 | 6篇 |
排序方式: 共有3466条查询结果,搜索用时 62 毫秒
81.
Bumhee Lim Yangyang Cheng Takehiro Kato Anh-Tuan Pham Eliott Le Du Abhaya Kumar Mishra Elija Grinhagena Dimitri Moreau Naomi Sakai Jerome Waser Stefan Matile 《Helvetica chimica acta》2021,104(8):e2100085
Thiol-mediated uptake is emerging as method of choice to penetrate cells. This study focuses on irreversible covalent inhibitors of thiol-mediated uptake. High-content high-throughput screening of the so far largest collection of hypervalent iodine reagents affords inhibitors that are more than 250 times more active than Ellman’s reagent and rival the best dynamic covalent inhibitors. Comparison with other irreversible reagents reveals that inhibition within one series follows reactivity, whereas inhibition across series deviates from reactivity. These trends support that molecular recognition, besides dynamic covalent exchange, contributes significantly to thiol-mediated uptake. The most powerful inhibitors besides the best hypervalent iodine reagents were Fukuyama’s nosyl protecting group and super-cinnamaldehydes that have been introduced as irreversible activators of the pain receptor TRPA1. Considering that several viruses use different forms of thiol-mediated uptake to enter cells, the identification of new irreversible inhibitors of thiol-mediated uptake is of general interest for the discovery of new antivirals. 相似文献
82.
83.
Bilal Ahmed Seung-Bok Lee Rak-Hyun Song Jong-Won Lee Tak-Hyoung Lim Seok-Joo Park 《Journal of Solid State Electrochemistry》2014,18(2):435-443
(La0.8Sr0.2)0.95MnO3?δ (LSM)–Gd0.1Ce0.9O2?δ (gadolinium-doped ceria, GDC) composite cathode material was developed and characterized in terms of chemical stability, sintering behaviour, electrical conductivity, mechanical strength and microstructures to assess its feasibility as cathode support applications in cathode-supported fuel cell configurations. The sintering inhibition effect of LSM, in the presence of GDC, was observed and clearly demonstrated. The mechanical characterization of developed composites revealed that fracture behaviour is directly affected by pore size distribution. The Weibull strength distribution showed that for bimodal pore size distribution, two different fracture rates were present. Furthermore, the contiguity of LSM and GDC grains was calculated with image analysis, and correlation of microstructural features with mechanical and electrical properties was established. Subsequently, an LSM/GDC-based cathode-supported direct carbon fuel cell (DCFC) with Ni/ScSZ (scandia-stabilised zirconia) anode was successfully fabricated via slurry coating and co-firing techniques. The microstructures of electrodes and electrolyte layers were observed to confirm the desired morphology after co-sintering, and a single cell was electrochemically characterized in solid oxide fuel cell (SOFC) and DCFC mode with ambient air as oxidant. The higher values of open-circuit voltage indicated that the electrolyte layer prepared by vacuum slurry coating is dense enough. The corresponding peak power densities at 850 °C were 450 and 225 mW cm?2 in SOFC and DCFC mode, respectively. Electrochemical impedance spectroscopy was carried out to observe electrode polarization and ohmic resistance. 相似文献
84.
Candy Haley Yi Xuan Lim Milos Nesladek Prof. Kian Ping Loh 《Angewandte Chemie (International ed. in English)》2014,53(1):215-219
Using IR spectroscopy, high‐pressure reactions of molecules were observed in liquids entrapped by graphene nanobubbles formed at the graphene–diamond interface. Nanobubbles formed on graphene as a result of thermally induced bonding of its edges with diamond are highly impermeable, thus providing a good sealing of solvents within. Owing to the optical transparency of graphene and diamond, high‐pressure chemical reactions within the bubbles can be probed with vibrational spectroscopy. By monitoring the conformational changes of pressure‐sensitive molecules, the pressure within the nanobubble can be calibrated as a function of temperature and it is about 1 GPa at 600 K. The polymerization of buckministerfullerene (C60), which is symmetrically forbidden under ambient conditions, is observed to proceed in well‐defined stages in the pressurized nanobubbles. 相似文献
85.
Band‐Gap Manipulations of Monolayer Graphene by Phenyl Radical Adsorptions: A Density Functional Theory Study 下载免费PDF全文
Phenyl radical (Ph.) adsorption on monolayer graphene sheets is used to investigate the band‐gap manipulation of graphene through density functional theory. Adsorption of a single Ph. on graphene breaks the aromatic π‐bond and generates an unpaired electron, which is delocalized to the ortho or para position. Adsorption of a second radical at the ortho or para position saturates the radical by electron pairing and results in semiconducting graphene. Adsorption of a second radical at the ortho position (ortho–ortho pairing) is found to be more favorable than adsorption at the para position (ortho–para pairing), and the ortho–ortho pairing has stronger effects on band‐gap opening compared with ortho–para pairing. Adsorption of even numbers of Ph. on graphene by ortho–ortho and ortho–para pairings, in general, increases the band gap. Our study shows promise of band‐gap manipulation in monolayer graphene by Ph. adsorption, leading to potential wider applications of graphene. 相似文献
86.
Eun-Sil Park Dae-Hwan Jang Young-In Lee Chan Woo Jung Dong woo Lim Bum Sung Kim Young-keun Jeong Nosang V. Myung Yong-Ho Choa 《Research on Chemical Intermediates》2014,40(7):2565-2570
Conducting polymers are excellent sensing materials in the design of bioanalytical sensors because of their electronic conductivity, low energy optical transitions, biocompatibility, and room temperature operation. Among them, Polypyrrole (Ppy) is one of the most extensively used conducting polymers because of a number of properties such as redox activity, rapid electron transfer, and ability to link a variety of biomolecules to pyrrole groups by chemical treatment. In this study, Ppy nanowires were synthesized by an electrospinning method. The nanowires were prepared from a solution mixture of Ppy and poly(ethylene oxide). The method of detection in such a device is based on the selective binding of antigen onto an antibody that is covalently attached to the nanowires. Thus, anti-IgG was immobilized on Ppy nanowires using an EDC {[N-(3-dimethyl aminopropyl)-N2-ethylcarbodiimide hydrochloride]}-NHS(N-hydrosuccinimide) modified technique. Fluorescence images of BSA–FITC (fluorescein isothiocyanate labeling of bovine serum albumin) conjugation demonstrated that antibody was functionalized on the Ppy nanowires without non-specific binding and facilitated selective detection of antigen. Current–voltage (I–V) characterization was used to monitor the change in the conductivity of nanowires while the specific binding interaction occurred. These results of electrical properties enable Ppy nanowire-based biosensors to detect biomolecules in real-time. 相似文献
87.
Chaohai Wang Dr. Jeonghun Kim Dr. Jing Tang Dr. Jongbeom Na Prof. Yong-Mook Kang Minjun Kim Hyunsoo Lim Prof. Yoshio Bando Prof. Jiansheng Li Prof. Yusuke Yamauchi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(5):2082-2086
Carbon aerogels (CAs) with 3D interconnected networks hold promise for application in areas such as pollutant treatment, energy storage, and electrocatalysis. In spite of this, it remains challenging to synthesize high-performance CAs on a large scale in a simple and sustainable manner. We report an eco-friendly method for the scalable synthesis of ultralight and superporous CAs by using cheap and widely available agarose (AG) biomass as the carbon precursor. Zeolitic imidazolate framework-8 (ZIF-8) with high porosity is introduced into the AG aerogels to increase the specific surface area and enable heteroatom doping. After pyrolysis under inert atmosphere, the ZIF-8/AG-derived nitrogen-doped CAs show a highly interconnected porous mazelike structure with a low density of 24 mg cm−3, a high specific surface area of 516 m2 g−1, and a large pore volume of 0.58 cm−3 g−1. The resulting CAs exhibit significant potential for application in the adsorption of organic pollutants. 相似文献
88.
Hyeohn Kim Sang Won Im Nam Heon Cho Da Hye Seo Ryeong Myeong Kim Yae‐Chan Lim Hye‐Eun Lee Hyo‐Yong Ahn Ki Tae Nam 《Angewandte Chemie (International ed. in English)》2020,59(31):12976-12983
Chiral optical metamaterials with delicate structures are in high demand in various fields because of their strong light–matter interactions. Recently, a scalable strategy for the synthesis of chiral plasmonic nanoparticles (NPs) using amino acids and peptides has been reported. Reported herein, 3D chiral gold NPs were synthesized using dipeptide γ‐Glu‐Cys and Cys‐Gly and analyzed crystallographically. The γ‐Glu‐Cys‐directed NPs present a cube‐like outline with a protruding chiral wing. In comparison, the NPs synthesized with Cys‐Gly exhibited a rhombic dodecahedron‐like outline with curved edges and elliptical cavities on each face. Morphology analysis of intermediates indicated that γ‐Glu‐Cys generated an intermediate concave hexoctahedron morphology, while Cys‐Gly formed a concave rhombic dodecahedron. NPs synthesized with Cys‐Gly are named 432 helicoid V because of their unique morphology and growth pathway. 相似文献
89.
Md Khairul Islam Ivan Lozada Lawag Tomislav Sostaric Edie Ulrich Danny Ulrich Terrence Dewar Lee Yong Lim Cornelia Locher 《Molecules (Basel, Switzerland)》2022,27(7)
Despite its cultural and nutritional importance for local Aboriginal people, the unusual insect honey produced by Western Australian honeypot ant (Camponotus inflatus) has to date been rarely investigated. This study reports on the honey’s physicochemical properties, its total phenolic, major sugars and 5-hydroxymethylfurfural contents, and its antioxidant activities. The honey’s color value is 467.63 mAU/63.39 mm Pfund, it has a pH of 3.85, and its electric conductivity is 449.71 µSiemens/cm. Its Brix value is 67.00, corresponding to a 33% moisture content. The total phenolics content is 19.62 mg gallic acid equivalent/100 g honey. Its antioxidant activity measured using the DPPH* (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing–antioxidant power) assays is 1367.67 µmol Trolox/kg and 3.52 mmol Fe+2/kg honey, respectively. Major sugars in the honey are glucose and fructose, with a fructose-to-glucose ratio of 0.85. Additionally, unidentified sugar was found in minor quantities. 相似文献
90.
Tae Woo Kim Eun‐Jin Oh Ah‐Young Jee Seung Tae Lim Dae Hoon Park Minyung Lee Sang‐Hoon Hyun Prof. Jin‐Ho Choy Prof. Seong‐Ju Hwang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(41):10752-10761
A colloidal suspension of exfoliated, layered cobalt oxide nanosheets has been synthesized through the intercalation of quaternary tetramethylammonium ions into protonated lithium cobalt oxide. According to atomic force microscopy, exfoliated nanosheets of layered cobalt oxide show a plateau‐like height profile with nanometer‐level height, underscoring the formation of unilamellar 2D nanosheets. The exfoliation of layered cobalt oxide was cross‐confirmed by X‐ray diffraction, UV/Vis spectroscopy, and transmission electron microscopy. The maintenance of the hexagonal in‐plane structure of the cobalt oxide lattice after the exfoliation process was evidenced by selected‐area electron diffraction and Co K‐edge X‐ray absorption near‐edge structure analysis. The zeta‐potential measurements clearly demonstrated the negative surface charge of cobalt oxide nanosheets. Adopting the nanosheets of layered cobalt oxide as a precursor, we were able to prepare the monodisperse CoO nanocrystals with a particle size of ≈10 nm as well as the heterolayered film composed of cobalt oxide monolayer and polycation. 相似文献