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961.
Magnetically Encoded Luminescent Composite Nanoparticles through Layer‐by‐Layer Self‐Assembly
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Prof. Dr. Erqun Song Weiye Han Hongyan Xu Yunfei Jiang Dan Cheng Prof. Dr. Yang Song Prof. Dr. Mark T. Swihart 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(45):14642-14649
Sensitive and rapid detection of multiple analytes and the collection of components from complex samples are important in fields ranging from bioassays/chemical assays, clinical diagnosis, to environmental monitoring. A convenient strategy for creating magnetically encoded luminescent CdTe@SiO2@n Fe3O4 composite nanoparticles, by using a layer‐by‐layer self‐assembly approach based on electrostatic interactions, is described. Silica‐coated CdTe quantum dots (CdTe@SiO2) serve as core templates for the deposition of alternating layers of Fe3O4 magnetic nanoparticles and poly(dimethyldiallyl ammonium chloride), to construct CdTe@SiO2@n Fe3O4 (n=1, 2, 3, …?) composite nanoparticles with a defined number (n) of Fe3O4 layers. Composite nanoparticles were characterized by zeta‐potential analysis, fluorescence spectroscopy, vibrating sample magnetometry, and transmission electron microscopy, which showed that the CdTe@SiO2@n Fe3O4 composite nanoparticles exhibited excellent luminescence properties coupled with well‐defined magnetic responses. To demonstrate the utility of these magnetically encoded nanoparticles for near‐simultaneous detection and separation of multiple components from complex samples, three different fluorescently labeled IgG proteins, as model targets, were identified and collected from a mixture by using the CdTe@SiO2@n Fe3O4 nanoparticles. 相似文献
962.
Cerium‐Based M4L4 Tetrahedra as Molecular Flasks for Selective Reaction Prompting and Luminescent Reaction Tracing
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Yang Jiao Dr. Jian Wang Dr. Pengyan Wu Liang Zhao Dr. Cheng He Jing Zhang Prof. Chunying Duan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2224-2231
The application of metal–organic polyhedra as “molecular flasks” has precipitated a surge of interest in the reactivity and property of molecules within well‐defined spaces. Inspired by the structures of the natural enzymatic pockets, three metal–organic neutral molecular tetrahedral, Ce‐TTS, Ce‐TNS and Ce‐TBS (H6TTS: N′,N′′,N′′′‐nitrilotris‐4,4′,4′′‐(2‐hydroxybenzylidene)‐benzohydrazide; H6TNS: N′,N′′,N′′′‐nitrilotris‐6,6′,6′′‐(2‐hydroxybenzylidene)‐2‐naphthohydrazide; H6TBS: 1,3,5‐ phenyltris ‐4,4′,4′′‐(2‐hydroxybenzylidene)benzohydrazide), which exhibit different size of the edges and cavities, were achieved through self‐assembly by incorporating robust amide‐containing tridentate chelating sites into the fragments of the ligands. They acted as molecular flasks to prompt the cyanosilylation of aldehydes with excellent selectivity towards the substrates size. The amide groups worked as trigger sites and catalytic driven forces to achieve efficient guest interactions, enforcing the substrates proximity within the cavity. Experiments on catalysts with the different cavity radii and substrates with the different molecular size demonstrated that the catalytic performance exhibited enzymatical catalytic mechanism and occurred in the molecular flask. These amides were also able to amplify guest‐bonding events into the measurable outputs for the detection of concentration variations of the substrates, providing the possibility for metal–organic hosts to work as smart molecular flasks for the luminescent tracing of catalytic reactions. 相似文献
963.
Dr. Shihui Li Dr. Meiyan Wang Bo Liu Lei Li Prof. Jianhua Cheng Dr. Chunji Wu Dr. Dongtao Liu Prof. Dr. Jingyao Liu Prof. Dr. Dongmei Cui 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15493-15498
The first four‐coordinate methanediide/alkyl lutetium complex (BODDI)Lu2(CH2SiMe3)2(μ2‐CHSiMe3)(THF)2 (BODDI=ArNC(Me)CHCOCHC(Me)NAr, Ar=2,6‐iPr2C6H3) ( 1 ) was synthesized by a thermolysis methodology through α‐H abstraction from a Lu–CH2SiMe3 group. Complex 1 reacted with equimolar 2,6‐iPrC6H3NH2 and Ph2C?O to give the corresponding lutetium bridging imido and oxo complexes (BODDI)Lu2(CH2SiMe3)2(μ2‐N‐2,6‐iPr2C6H3)(THF)2 ( 2 ) and (BODDI)Lu2(CH2SiMe3)2(μ2‐O)(THF)2 ( 3 ). Treatment of 3 with Ph2C?O (4 equiv) caused a rare insertion of Lu–μ2‐O bond into the C?O group to afford a diphenylmethyl diolate complex 4 . Reaction of 1 with PhN=C?O (2 equiv) led to the migration of SiMe3 to the amido nitrogen atom to give complex (BODDI)Lu2(CH2SiMe3)2‐μ‐{PhNC(O)CHC(O)NPh(SiMe3)‐κ3N,O,O}(THF) ( 5 ). Reaction of 1 with tBuN?C formed an unprecedented product (BODDI)Lu2(CH2SiMe3){μ2‐[η2:η2‐tBuNC(=CH2)SiMe2CHC?NtBu‐κ1N]}(tBuN?C)2 ( 6 ) through a cascade reaction of N?C bond insertion, sequential cyclometalative γ‐(sp3)‐H activation, C?C bond formation, and rearrangement of the newly formed carbene intermediate. The possible mechanistic pathways between 1 , PhN?C?O, and tBuN?C were elucidated by DFT calculations. 相似文献
964.
Changduo Pan Ablimit Abdukader Jie Han Prof. Dr. Yixiang Cheng Prof. Dr. Chengjian Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(13):3606-3609
A ruthenium‐catalyzed direct C7 amidation of indoline C?H bonds with sulfonyl azides was developed. This procedure allows the synthesis of a variety of 7‐amino‐substituted indolines, which are useful in pharmaceutical. The good functional tolerances, as well as the mild conditions, are prominent feature of this method. 相似文献
965.
Highly Curved Bowl‐Shaped Fragments of Fullerenes: Synthesis,Structural Analysis,and Physical Properties
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Min‐Kuan Chen Hsin‐Ju Hsin Dr. Tsun‐Cheng Wu Bo‐Yan Kang Yen‐Wei Lee Prof. Ming‐Yu Kuo Prof. Yao‐Ting Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):598-608
Highly curved buckybowls 3 , 4 , and 5 were synthesized from planar precursors, fluoranthenes 8 , benzo[k]fluoranthenes 10 and naphtho[1,2‐k]‐cyclopenta[cd]fluoranthenes 12 , respectively, using straightforward palladium‐catalyzed cyclization reactions. These fluoranthene‐based starting materials were easily prepared from 1,8‐bis(arylethynyl)naphthalenes 6 . Both buckybowls 3 and 4 are fragments of C60, whereas 5 is a unique subunit of C70. The curved structures were identified by X‐ray crystallography, and they are deep bowls. The maximum π‐orbital axis vector (POAV) pyramidalization angle in both 3 and 4 is 12.8°. Such a high curvature is very rarely obtained. Buckybowls 5 are less curved than the others because they have a lower density of five‐membered rings, analogous to the tube portion of C70. Cyclopentaannulation increases the bowl depths of 3 and 4 , but not the maximum POAV pyramidalization angle. Among the eight buckybowls studied herein, five form polar crystals. The bowl‐to‐bowl inversion dynamics of these buckybowls can be classified into two types; one has a planar transition structure, whereas the other has an S‐shaped transition structure. A larger longitudinal length of these buckybowls corresponds to a stronger preference for the latter. The photophysical properties of these buckybowls were examined and compared with those of C60 and C70. Buckybowls 5 have absorption bands at wavelengths greater than 450 nm, which are similar to those of C70. The chiral resolution of the mono‐substituted buckybowl 4 ac was also studied by using HPLC with a chiral column. 相似文献
966.
Bi Xiong Pingping Zhao Kai Hu Lina Zhang Gongzhen Cheng 《Cellulose (London, England)》2014,21(3):1183-1192
Urea can improve the solubility and stability of cellulose in aqueous alkali solution, while its role has not come to a conclusion. To reveal the role of urea in solution, NMR was introduced to investigate the interaction between urea and the other components in solution. Results from chemical shifts and longitudinal relaxation times show that: (1) urea has no strong direct interaction with cellulose as well as NaOH; (2) urea does not have much influence on the structural dynamics of water. Urea may play its role through van der Waals force. It may accumulate on the cellulose hydrophobic region to prevent dissolved cellulose molecules from re-gathering. The driving force for the self-assembly of cellulose and urea molecules might be hydrophobic interaction. In the process of cellulose dissolution, OH? breaks the hydrogen bonds, Na+ hydrations stabilize the hydrophilic hydroxyl groups and urea stabilizes the hydrophobic part of cellulose. 相似文献
967.
968.
人全血中锶元素的分布及血浆中锶元素的形态分析 总被引:1,自引:0,他引:1
建立了基于液相色谱-电感耦合等离子体质谱(LC-ICP-MS)联用定量分析血浆中锶元素形态的方法,方法检出限为0.3 ng/mL,无机锶加标回收率为88%~97%,利用LC-ICP-MS分析,无机锶质量浓度在1.0~50.0μg/L之间时,线性回归系数r大于0.999。通过湿法消解,对73份人血和血浆用电感耦合等离子体质谱(ICP-MS)测定得出全血锶平均含量为38.1 ng/mL,血浆平均锶含量为35.8 ng/mL,说明全血中绝大部分锶存在于血浆中。通过LC-ICP-MS对血浆锶进行形态分析得出无机锶平均含量为10.2%,随色谱流出的有机锶平均含量为18.7%,而未随色谱流出的有机锶平均含量为71.1%,因此可推断摄入人体的锶主要以有机锶的形式发挥其生理作用。 相似文献
969.
A Borinic Acid Polymer with Fluoride Ion‐ and Thermo‐responsive Properties that are Tunable over a Wide Temperature Range
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Dr. Wen‐Ming Wan Dr. Fei Cheng Prof. Dr. Frieder Jäkle 《Angewandte Chemie (International ed. in English)》2014,53(34):8934-8938
A new type of smart borinic acid polymer with luminescence and multiple stimuli‐responsive properties is reported. In DMSO with small amounts of water, the homopolymer PBA shows a tunable upper critical solution temperature (UCST). As the amount of water increases from 0 to 2.5 % (v/v), the UCST rises linearly from 20 °C to 100 °C (boiling point of water). Thus, the thermal responsive behavior can be tuned over a wide temperature range. Furthermore, polymer solutions in DMSO show a reversible response to fluoride ions, which can be correlated to the presence of the Lewis acidic borinic acid groups. Upon addition of fluoride, the polymer becomes soluble because the functional R2BOH groups are converted into ionic [R2BF2]? groups, but turns insoluble again upon addition of H2O, which reverses this process. 相似文献
970.
Highly Enantioselective Kinetic Resolution of Axially Chiral BINAM Derivatives Catalyzed by a Brønsted Acid
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Dr. Dao‐Juan Cheng Liang Yan Prof. Dr. Shi‐Kai Tian Ming‐Yue Wu Lu‐Xin Wang Zi‐Li Fan Dr. Sheng‐Cai Zheng Prof. Dr. Xin‐Yuan Liu Prof. Dr. Bin Tan 《Angewandte Chemie (International ed. in English)》2014,53(14):3684-3687
A highly efficient strategy for the kinetic resolution of axially chiral BINAM derivatives involving a chiral Brønsted acid‐catalyzed imine formation and transfer hydrogenation cascade process was developed. The kinetic resolution provides a convenient route to chiral BINAM derivatives in high yields with excellent enantioselectivities. 相似文献