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951.
Jian Wen Li‐Li Zhu Qing‐Wei Bi Zhu‐Qing Shen Xiao‐Xiao Li Xin Li Zhen Wang Prof. Zili Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):974-978
Hydrogen‐bond mediated coupling of 1,2,3‐triazoles to indoles and pyrroles results in N2 selective functionalization of the triazole moiety in moderate to excellent yields. The reaction was tolerant of un‐, mono‐ and disubstituted triazoles and was applied to synthesize tryptophan derived fluorescent amino acids. 相似文献
952.
Tian Wen Prof. Dr. Xiao‐Ping Zhou De‐Xiang Zhang Prof. Dr. Dan Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):644-648
Three 2D luminescent isomeric porous coordination polymers are synthesized and characterized. Their luminescence properties can be modified by grinding and they can act as mechanochromic materials and their properties are probably related to the weak interactions of cuprophilicity and π–π interactions. 相似文献
953.
Versatile Iridicycle Catalysts for Highly Efficient and Chemoselective Transfer Hydrogenation of Carbonyl Compounds in Water 下载免费PDF全文
Dinesh Talwar Dr. Xiaofeng Wu Dr. Ourida Saidi Noemí Poyatos Salguero Prof. Jianliang Xiao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12835-12842
Cyclometalated iridium complexes are shown to be highly efficient and chemoselective catalysts for the transfer hydrogenation of a wide range of carbonyl groups with formic acid in water. Examples include α‐substituted ketones (α‐ether, α‐halo, α‐hydroxy, α‐amino, α‐nitrile or α‐ester), α‐keto esters, β‐keto esters and α,β‐unsaturated aldehydes. The reduction was carried out at substrate/catalyst ratios of up to 50 000 at pH 4.5 and required no organic solvent. The protocol provides a practical, easy and efficient way for the synthesis of β‐functionalised secondary alcohols, such as β‐hydroxyethers, β‐hydroxyamines and β‐hydroxyhalo compounds, which are valuable intermediates in pharmaceutical, fine chemical, perfume and agrochemical synthesis. 相似文献
954.
Metal‐Free Oxidative Radical Addition of Carbonyl Compounds to α,α‐Diaryl Allylic Alcohols: Synthesis of Highly Functionalized Ketones 下载免费PDF全文
Xue‐Qiang Chu Hua Meng You Zi Prof. Dr. Xiao‐Ping Xu Prof. Dr. Shun‐Jun Ji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):17198-17206
A metal‐free direct alkylation of simple carbonyl compounds (ketones, esters, and amides) with α,α‐diaryl allylic alcohols is described. The protocol provides facile access to highly functionalized dicarbonyl ketones by a radical addition/1,2‐aryl migration cascade. The regioselectivity of the reaction was precisely controlled by the nature of the carbonyl compound. 相似文献
955.
Tailoring 3,3′‐Dihydroxyisorenieratene to Hydroxystilbene: Finding a Resveratrol Analogue with Increased Antiproliferation Activity and Cell Selectivity 下载免费PDF全文
Yan‐Fei Kang Wen‐Jing Yan Ting‐Wen Zhou Dr. Fang Dai Dr. Xiu‐Zhuang Li Xia‐Zhen Bao Yu‐Ting Du Cui‐Hong Yuan Hai‐Bo Wang Xiao‐Rong Ren Dr. Qiang Liu Dr. Xiao‐Ling Jin Prof. Dr. Bo Zhou Prof. Dr. Jie Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(29):8904-8908
Four novel compounds were designed by “tailoring” 3,3′‐dihydroxyisorenieratene (a natural carotenoid) based on an isoprene unit retention truncation strategy. Among them, the smallest molecule 1 (2,3,6,2′,3′,6′‐hexamethyl‐4,4′‐dihydroxy‐trans‐stilbene) was concisely synthesized in a one‐pot Stille–Heck tandem sequence, and surfaced as a promising lead molecule in terms of its selective antiproliferative activity mediated by blocking the NCI‐H460 cell cycle in G1 phase. Additionally, theoretical calculations and cell uptake experiments indicate that the unique polymethylation pattern of compound 1 significantly induces a conformational change shift out of planarity and increases its cell uptake and metabolic stability. The observation should be helpful to rationally design resveratrol‐inspired antiproliferative agents. 相似文献
956.
Development of a Halide‐Free Aluminium‐Based Catalyst for the Synthesis of Cyclic Carbonates from Epoxides and Carbon Dioxide 下载免费PDF全文
Dr. Jose A. Castro‐Osma Prof. Michael North Dr. Xiao Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15005-15008
Kinetic studies of the synthesis of glycerol carbonate from glycidol and carbon dioxide have been carried out. These showed that under suitable reaction conditions, bimetallic aluminium(salen) complex 4 is able to catalyse the conversion of epoxides into the corresponding cyclic carbonates without the need for a co‐catalyst. 相似文献
957.
Peng Xiao Jinming Zhang Ye Feng Jin Wu Jiasong He Jun Zhang 《Cellulose (London, England)》2014,21(4):2369-2378
Using ionic liquid 1-allyl-3-methylimidazolium chloride as reaction medium, a series of novel cellulose esters containing phosphorus including cellulose diphenyl phosphate (C-Dp) and cellulose acetate (CA)–diphenyl phosphate mixed esters was synthesized homogeneously. The degree of substitution was well controlled by altering reaction conditions, such as the molar ratio of the acylating reagents/anhydroglucose unit and reaction time. The structure and thermal properties of cellulose esters were characterized by FTIR, NMR, wide-angle X-ray powder diffraction and differential scanning calorimetry. All the products possessed excellent solubility in some common organic solvents, and transparent films of cellulose esters were obtained by solution casting. In contrast to C-Dp, CA–diphenyl phosphate mixed esters showed clear glass transitions. More interestingly, these cellulose mixed esters exhibited thermoplastic behavior and could be processed by traditional melt processing methods. 相似文献
958.
Thermal Ethane Activation by Bare [V2O5]+ and [Nb2O5]+ Cluster Cations: on the Origin of Their Different Reactivities 下载免费PDF全文
Dr. Xiao‐Nan Wu Dr. Shi‐Ya Tang Dr. Hai‐Tao Zhao Dr. Thomas Weiske Dr. Maria Schlangen Prof. Dr. Helmut Schwarz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(22):6672-6677
The gas‐phase reactivity of [V2O5]+ and [Nb2O5]+ towards ethane has been investigated by means of mass spectrometry and density functional theory (DFT) calculations. The two metal oxides give rise to the formation of quite different reaction products; for example, the direct room‐temperature conversions C2H6→C2H5OH or C2H6→CH3CHO are brought about solely by [V2O5]+. In distinct contrast, for the couple [Nb2O5]+/C2H6, one observes only single and double hydrogen‐atom abstraction from the hydrocarbon. DFT calculations reveal that different modes of attack in the initial phase of C?H bond activation together with quite different bond‐dissociation energies of the M?O bonds cause the rather varying reactivities of [V2O5]+ and [Nb2O5]+ towards ethane. The gas‐phase generation of acetaldehyde from ethane by bare [V2O5]+ may provide mechanistic insight in the related vanadium‐catalyzed large‐scale process. 相似文献
959.
以熔融纺丝聚氯乙烯(PVC)中空纤维多孔膜为增强体,聚偏氟乙烯(PVDF)为成膜聚合物,聚乙烯吡咯烷酮(PVP)为添加剂,N,N-二甲基乙酰胺(DMAc)为溶剂,配置铸膜液,采用同心圆牵引-涂覆法制备了异质增强型PVDF中空纤维膜.制备过程中,采用预湿溶液对增强体基膜表面进行预处理,研究了预湿溶液组成及含量对异质增强型PVDF中空纤维膜结构与性能的影响.结果表明,未经预湿处理的异质增强型PVDF中空纤维膜具有较厚的致密界面层;预湿溶液可对基膜表面孔起到保护作用,使异质增强型PVDF中空纤维膜的界面层变薄或形成多孔界面层,有益于改善增强型PVDF中空纤维膜的通透性能;与二甲基乙酰胺(DMAc)水溶液相比,以乙醇水溶液为预湿溶液所得异质增强型PVDF中空纤维膜的性能较优;当预湿液中乙醇含量为60 wt%时,所得增强型PVDF中空纤维膜的渗透性能较优,拉伸强度可达8.61 MPa. 相似文献
960.
用水热法制备了Dy3+单掺及Dy3+,Er3+双掺GdVO4纳米荧光粉,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱仪(FTIR)和荧光(FL)光谱对合成样品的结构、形貌和发光性能进行表征;探讨了Dy3+掺杂浓度、络合剂对GdVO4:Dy3+纳米晶的结构、形貌和发光性能的影响;考察了不同波长的近红外光和紫外光激发的GdVO4:Dy3+,Er3+,得到不同颜色的上转换和下转换荧光光谱。以760~830 nm近红外光和210~380 nm紫外光激发GdVO4:Dy3+纳米晶,可获得Dy3+蓝绿色双模发光;其中蓝光来自于Dy3+离子的4F9/2→6H15/2跃迁,绿光由Dy3+离子4F9/2→6H13/2跃迁产生。 相似文献