全文获取类型
收费全文 | 19682篇 |
免费 | 3293篇 |
国内免费 | 2302篇 |
专业分类
化学 | 13682篇 |
晶体学 | 177篇 |
力学 | 1129篇 |
综合类 | 118篇 |
数学 | 2717篇 |
物理学 | 7454篇 |
出版年
2024年 | 86篇 |
2023年 | 428篇 |
2022年 | 645篇 |
2021年 | 720篇 |
2020年 | 849篇 |
2019年 | 772篇 |
2018年 | 695篇 |
2017年 | 661篇 |
2016年 | 984篇 |
2015年 | 959篇 |
2014年 | 1093篇 |
2013年 | 1463篇 |
2012年 | 1685篇 |
2011年 | 1755篇 |
2010年 | 1228篇 |
2009年 | 1098篇 |
2008年 | 1249篇 |
2007年 | 1101篇 |
2006年 | 977篇 |
2005年 | 882篇 |
2004年 | 703篇 |
2003年 | 614篇 |
2002年 | 683篇 |
2001年 | 543篇 |
2000年 | 438篇 |
1999年 | 429篇 |
1998年 | 342篇 |
1997年 | 311篇 |
1996年 | 331篇 |
1995年 | 291篇 |
1994年 | 232篇 |
1993年 | 163篇 |
1992年 | 165篇 |
1991年 | 158篇 |
1990年 | 123篇 |
1989年 | 94篇 |
1988年 | 54篇 |
1987年 | 56篇 |
1986年 | 71篇 |
1985年 | 47篇 |
1984年 | 32篇 |
1983年 | 26篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1980年 | 4篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1957年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
991.
Xia Li Bin Liu Fengen Wang Xinfeng Ma Zengmei Li Dongliang Guo 《Analytical letters》2018,51(5):702-716
An ultrahigh-performance liquid chromatography–tandem mass spectrometry method was developed and validated for the simultaneous determination of sterigmatocystin, verruculogen, enniatin A, fusarenon-X, fumonisins B1, B2, B3, aflatoxins B1, B2, G1, G2, ochratoxin A, deoxynivalenol, 3-acetyldeoxynivalenol, 5-acetyldeoxynivalenol, and zearalenone. The mycotoxins were extracted and cleaned up using a multitoxin column, separated on a C18 column, and then detected on a triple-quadrupole mass spectrometer. The limits of detection and quantification ranged within 0.2–2?µg/kg and 1–10?µg/kg, respectively. The recoveries ranged from 70.8 to 118.4%, with relative standard deviations below 15%. The method was used to analyze 80 samples obtained from Shandong Province in China. Fifty-eight samples were contaminated with 10 mycotoxins at concentrations ranging from 1.4 to 6566.1?µg/kg. Some samples exceeded the maximum limits in China and in European regulations for mycotoxins in unprocessed maize. 相似文献
992.
Yi Xu Siyu Guo Xinjian Mao Jian Feng 《Journal of Dispersion Science and Technology》2018,39(3):443-451
The self-assembly behaviors of a series of zwitterionic heterogemini surfactants CmH2m+1-PO4–(CH2)2-N+(CH3)2-CnH2n+1, abbreviated as Cm-P-N-Cn (m, n?=?9, 9; 9, 12; 9, 15; 9, 18; 12, 12; 12, 15; 12, 18; 15, 15; 15, 18; 18, 18), have been investigated in aqueous solution by the dissipative particle dynamics (DPD) method. Morphologies such as sphere (S), rod (R), planar grid (PG), lamella (L), honeycomb (H), one-, two-, and three-dimensional tunnels (1DT, 2DT, and 3DT) have been observed showing more diversities than those of the corresponding symmetric gemini surfactants Cm-N-N-Cm (m?=?9, 12, 15, 18). With the increase of surfactant concentration in the aqueous solution, a distinct transition path ‘‘S—R—PG—3DT—L—2DT—1DT’’ is proved to be common for all the Cm-P-N-Cn systems. Besides, the hydrophobic chain length has a significant influence on the self-assembly behaviors in the case of m?≠?n. Radial distribution function is an effective method to quantitatively evaluate the interaction and relationship between each functional group in the surfactant molecule and water. Results can provide a new insight into the self-assembly behaviors of zwitterionic heterogemini surfactants and the corresponding applications. 相似文献
993.
Xiaoyi Yang Binbin Zhang Chaohua Guo Jianbo Li Xingang Wang 《Journal of Dispersion Science and Technology》2018,39(10):1518-1523
The present work aimed at research the physic-chemical properties of the interaction of N-decyl-O-chitosan sulfate (an amphiphilic chitosan derivative, C10-OCHS) with cetyltrimetylammonium bromide (CTAB) by the steady-state fluorescent, static/dynamic surface tension, turbidity and transmission electron microscopy (TEM). The results showed that the complex of C10-OCHS/CTAB had high surface activity and lower critical aggregation concentration. Besides, the C10-OCHS/CTAB could self-assemble into various aggregates like irregular spherical aggregates, vesicles or polydisperse aggregates from lower to higher concentrations of CTAB with a mixed C10-OCHS concentration of 200?mg/L. 相似文献
994.
Thermo‐triggered Release of CRISPR‐Cas9 System by Lipid‐Encapsulated Gold Nanoparticles for Tumor Therapy 下载免费PDF全文
Dr. Peng Wang Dr. Lingmin Zhang Prof. Wenfu Zheng Dr. Liman Cong Zhaorong Guo Yangzhouyun Xie Le Wang Rongbing Tang Qiang Feng Prof. Yoh Hamada Prof. Kohsuke Gonda Prof. Zhijian Hu Prof. Xiaochun Wu Prof. Xingyu Jiang 《Angewandte Chemie (International ed. in English)》2018,57(6):1491-1496
CRISPR/Cas9 system is a powerful toolbox for gene editing. However, the low delivery efficiency is still a big hurdle impeding its applications. Herein, we report a strategy to deliver Cas9‐sgPlk‐1 plasmids (CP) by a multifunctional vehicle for tumor therapy. We condensed CPs on TAT peptide‐modified Au nanoparticles (AuNPs/CP, ACP) via electrostatic interactions, and coated lipids (DOTAP, DOPE, cholesterol, PEG2000‐DSPE) on the ACP to form lipid‐encapsulated, AuNPs‐condensed CP (LACP). LACP can enter tumor cells and release CP into the cytosol by laser‐triggered thermo‐effects of the AuNPs; the CP can enter nuclei by TAT guidance, enabling effective knock‐outs of target gene (Plk‐1) of tumor (melanoma) and inhibition of the tumor both in vitro and in vivo. This AuNPs‐condensed, lipid‐encapsulated, and laser‐controlled delivery system provides a versatile method for high efficiency CRISPR/Cas9 delivery and targeted gene editing for treatment of a wide spectrum of diseases. 相似文献
995.
Fan Lv Zhiquan Lang Kangning Zhao Prof. Liang Zhou Dr. Lyudmila Moskaleva Prof. Shaojun Guo Prof. Liqiang Mai 《Angewandte Chemie (International ed. in English)》2018,57(2):496-500
Proton adsorption on metallic catalysts is a prerequisite for efficient hydrogen evolution reaction (HER). However, tuning proton adsorption without perturbing metallicity remains a challenge. A Schottky catalyst based on metal–semiconductor junction principles is presented. With metallic MoB, the introduction of n‐type semiconductive g‐C3N4 induces a vigorous charge transfer across the MoB/g‐C3N4 Schottky junction, and increases the local electron density in MoB surface, confirmed by multiple spectroscopic techniques. This Schottky catalyst exhibits a superior HER activity with a low Tafel slope of 46 mV dec?1 and a high exchange current density of 17 μA cm?2, which is far better than that of pristine MoB. First‐principle calculations reveal that the Schottky contact dramatically lowers the kinetic barriers of both proton adsorption and reduction coordinates, therefore benefiting surface hydrogen generation. 相似文献
996.
Fei Ding Quanbing Mou Yuan Ma Gaifang Pan Yuanyuan Guo Prof. Gangsheng Tong Prof. Chung Hang Jonathan Choi Prof. Xinyuan Zhu Prof. Chuan Zhang 《Angewandte Chemie (International ed. in English)》2018,57(12):3064-3068
Functional siRNAs are employed as cross‐linkers to direct the self‐assembly of DNA‐grafted polycaprolactone (DNA‐g‐PCL) brushes to form spherical and nanosized hydrogels via nucleic acid hybridization in which small interfering RNAs (siRNAs) are fully embedded and protected for systemic delivery. Owing to the existence of multivalent mutual crosslinking events inside, the crosslinked nanogels with tunable size exhibit not only good thermostability, but also remarkable physiological stability that can resist the enzymatic degradation. As a novel siRNA delivery system with spherical nucleic acid (SNA) architecture, the crosslinked nanogels can assist the delivery of siRNAs into different cells without any transfection agents and achieve the gene silencing effectively both in vitro and in vivo, through which a significant inhibition of tumor growth is realized in the anticancer treatment. 相似文献
997.
Yuebao Zhang Qianyou Guo Xianwei Sun Ji Lu Yanjun Cao Qiang Pu Zhiwen Chu Dr. Lu Gao Prof. Dr. Zhenlei Song 《Angewandte Chemie (International ed. in English)》2018,57(4):942-946
Convergent total synthesis of bryostatin 8 has been accomplished by an organosilane‐based strategy. The C ring is constructed stereoselectively through a geminal bis(silane)‐based [1,5]‐Brook rearrangement, and the B ring through geminal bis(silane)‐based Prins cyclization, thus efficiently joining the northern and southern parts of the molecule. 相似文献
998.
Elasticity‐Dependent Fast Underwater Adhesion Demonstrated by Macroscopic Supramolecular Assembly 下载免费PDF全文
Guannan Ju Dr. Mengjiao Cheng Fengli Guo Qian Zhang Prof. Feng Shi 《Angewandte Chemie (International ed. in English)》2018,57(29):8963-8967
Macroscopic supramolecular assembly (MSA) is a recent development in supramolecular chemistry to associate visible building blocks through non‐covalent interactions in a multivalent manner. Although various substrates (e.g. hydrogels, rigid materials) have been used, a general design rule of building blocks in MSA systems and interpretation of the assembly mechanism are lacking and are required. Herein we design three model systems with varied elastic modulus and correlated the MSA probability with the elasticity. Based on the effects of substrate deformability on multivalency, we have proposed an elastic‐modulus‐dependent rule that building blocks below a critical modulus of 2.5 MPa can achieve MSA for the used host/guest system. Moreover, this MSA rule applies well to the design of materials for fast underwater adhesion: Soft substrates (0.5 MPa) can achieve underwater adhesion within 10 s with one order of magnitude higher strength than that of rigid substrates (2.5 MPa). 相似文献
999.
A Multi‐signal Fluorescent Probe with Multiple Binding Sites for Simultaneous Sensing of Cysteine,Homocysteine, and Glutathione 下载免费PDF全文
Guo‐xing Yin Ting‐ting Niu Ya‐bing Gan Ting Yu Dr. Peng Yin Prof. Hai‐min Chen Prof. You‐yu Zhang Prof. Hai‐tao Li Prof. Shou‐zhuo Yao 《Angewandte Chemie (International ed. in English)》2018,57(18):4991-4994
A novel fluorescent probe was developed by integrating chlorinated coumarin and benzothiazolylacetonitrile and exploited for simultaneous detection of cysteine (Cys), homocysteine (Hcy), and glutathione (GSH). Featuring four binding sites and different reaction mechanisms for different biothiols, this probe exhibited rapid fluorescence turn‐on for distinguishing Cys, Hcy, and GSH with 108‐, 128‐, 30‐fold fluorescence increases at 457, 559, 529 nm, respectively, across different excitation wavelengths. Furthermore, the probe was successfully applied to the fluorescence imaging of endogenous Cys and GSH and exogenous Cys, Hcy, and GSH in living cells. 相似文献
1000.
Atomic layer deposition (ALD) of the pyrite‐type metal disulfides FeS2, CoS2, and NiS2 is reported for the first time. The deposition processes use iron, cobalt, and nickel amidinate compounds as the corresponding metal precursors and the H2S plasma as the sulfur source. All the processes are demonstrated to follow ideal self‐limiting ALD growth behavior to produce fairly pure, smooth, well‐crystallized, stoichiometric pyrite FeS2, CoS2, and NiS2 films. By these processes, the FeS2, CoS2, and NiS2 films can also be uniformly and conformally deposited into deep narrow trenches with aspect ratios as high as 10:1, which thereby highlights the broad and promising applicability of these ALD processes for conformal film coatings on complex high‐aspect‐ratio 3D architectures in general. 相似文献