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991.
运用第一性原理方法, 计算了B, P两种元素单掺杂和共掺杂的β -Si3N4材料的电子结构和光学性质. 结果表明: B掺杂体系的稳定性更高, 而P掺杂体系的离子性更强; 单掺和共掺杂均窄化带隙, 且共掺在禁带中引入深能级, 使局域态增强; 单掺杂体系介电函数虚部、吸收谱和能量损失谱各峰均发生红移、幅值减小, 而共掺后介电函数虚部主峰出现蓝移、能量损失峰展宽、高能区电子跃迁大大增强, 且控制共掺杂的B, P比例可获得较低的带电缺陷浓度. 相似文献
992.
Ya-Bin Tang Fan Sun Lin Teng Wen-Bin Li Shi-Min An Chun Zhang Xin-Jie Yang Hao-Yu Lv Xu-Ping Ding Liang Zhu Hong-Zhuan Chen 《Analytica chimica acta》2014
Dynamic, continuous, and simultaneous multi-analysis of transmitters is important for the delineation of the complex interactions between the neuronal and intercellular communications. But the analysis of the whole repertoire of classical transmitters of diverse structure is challenging due to their different physico-chemical properties and to their high polarity feature which leads to poor retention in traditional reversed-phase columns during LC–MS analysis. Here, an online microdialysis coupled with hydrophilic interaction chromatography–tandem mass spectrometry (online MD-HILIC–MS/MS) detection method was developed for the simultaneous measurement of the repertoire of classical transmitters (acetylcholine, serotonin, dopamine, norepinephrine, glutamate, GABA, and glycine). Stable isotope labeled internal standards and authentic matrix have been applied to guarantee reliable results. The method was successfully employed to reveal the characteristics of transmitter release from embryonal carcinoma stem cells. The method features simple procedure (no sample preparation), high recovery (≥73%), high accuracy (89.36% ≤ RE ≤ 116.89%), good reproducibility (2.18% ≤ RSD ≤ 14.56%), and sensitive limits of detection (2 pg for acetylcholine, serotonin, and glutamate, 10 pg for dopamine, norepinephrine, GABA, and glycine). It can be flexibly applied to determine the contents of the classical transmitters in other biological matrix samples with minor changes. 相似文献
993.
IR,Raman, and Surface‐enhanced Raman Spectroscopic Study on Triruthenium Dipyridylamide Diruthenium Nickel Dipyridylamide Family: Metal‐metal Bonding and Structures 下载免费PDF全文
Yu‐Chun Chiu Kuan‐Yi Ho a I‐Chia Chen Shao‐An Hua Ming‐Chuan Cheng Shie‐Ming Peng 《中国化学会会志》2014,61(12):1289-1296
We report the infrared, Raman, and surface‐enhanced Raman scattering (SERS) spectra of triruthenium dipyridylamido complexes and of diruthenium mixed nickel metal‐string complexes. From the results of analysis on the vibrational modes, we assigned their vibrational frequencies and structures. The infrared band at 323–326 cm?1 is assigned to the Ru3 asymmetric stretching mode for [Ru3(dpa)4Cl2]0–2+. In these complexes we observed no Raman band corresponding to the Ru3 symmetric stretching mode although this mode is expected to have substantial Raman intensity. There is no frequency shift in the Ru3 asymmetric stretching modes for the complexes with varied oxidational states. No splitting in Raman spectra for the pyridyl breathing line indicates similar bonding environment for both pyridyls in dpa– , thus a delocalized structure in the [Ru3]6–8+ unit is proposed. For Ru3(dpa)4(CN)2 complex series, we assign the infrared band at 302 cm?1 to the Ru3 asymmetric stretching mode and the weak Raman line at 285 cm?1 to the Ru3 symmetric stretching. Coordination to the strong axial ligand CN– weakens the Ru‐Ru bonding. For the diruthenium nickel complex [Ru2Ni(dpa)4Cl2]0–1+, the diruthenium stretching mode νRu‐Ru is assigned to the intense band at 327 and 333 cm?1 in the Raman spectra for the neutral and oxidized forms, respectively. This implies a strong Ru‐Ru metal‐metal bonding. 相似文献
994.
Jong Eel Park Kyeong Wan Woo Sang Un Choi Je Hyun Lee Kang Ro Lee 《Helvetica chimica acta》2014,97(1):56-63
Two new spirostane‐steroidal saponins, bletilnoside A ( 1 ) and bletilnoside B ( 2 ), together with five known compounds, 3 – 7 , were isolated from the roots of Bletilla striata (Thunb .) Reichb . F. The structures of the new compounds were determined based on their 1D‐ and 2D‐NMR spectral data. The isolated compounds 1 – 7 were tested for cytotoxicity against four human tumor cells (A549, SK‐OV‐3, SK‐MEL‐2, and HCT15) in vitro using a sulforhodamin B bioassay, and compounds 1, 2 , and 5 showed significant cytotoxicities against all tested tumor cell lines with IC50 values ranging from 3.98±0.16 to 12.10±0.40 μM . 相似文献
995.
Efficient Solvent‐Free Synthesis of Benzothiazine‐Fused Pyrrolo[3,4‐c]coumarins: Cycloaddition Reactions between Coumarin‐Based Dihydrobenzothiazoles and Isocyanides 下载免费PDF全文
Mehdi Khoobi Ali Ramazani Mohammad Mahdavi Alireza Foroumadi Saeed Emami Sang Woo Joo Katarzyna Ślepokura Tadeusz Lis Abbas Shafiee 《Helvetica chimica acta》2014,97(6):847-853
A new and unusual synthesis of benzothiazine‐fused pyrrolo[3,4‐c]coumarins, involving the ring‐opening of coumarin‐based dihydrobenzothiazoles and subsequent [4+1] cycloaddition reaction with isocyanides, was described. Thus, simple heating of various 3‐(2,3‐dihydro‐2‐methylbenzo[d]thiazol‐2‐yl)coumarins with isocyanides produced the title compounds in good yields under solvent‐free conditions. 相似文献
996.
Synthesis of Novel α‐(Acyloxy)‐α‐(quinolin‐4‐yl)acetamides by a Three‐Component Reaction between an Isocyanide,Quinoline‐4‐carbaldehyde,and Arenecarboxylic Acids 下载免费PDF全文
Jafar Taran Ali Ramazani Sang Woo Joo Katarzyna Ślepokura Tadeusz Lis 《Helvetica chimica acta》2014,97(8):1088-1096
Novel α‐(acyloxy)‐α‐(quinolin‐4‐yl)acetamides were synthesized by the Passerini three‐component reaction between an isocyanide, quinoline‐4‐carbaldehyde, and arenecarboxylic acids in H2O. The reactions were carried out in one pot at room temperature with quantitative yields. 相似文献
997.
Synthesis of 2,5‐Diketopiperazine Derivatives Using 2‐Isocyanophenyl 4‐Methylbenzoate as a Fragrant Convertible Isocyanide 下载免费PDF全文
A new protocol in which 2‐isocyanophenyl 4‐methylbenzoate is used as a convertible isocyanide for Ugi/deprotection + activation/cyclization synthesis of 2,5‐diketopiperazine derivatives has been developed. This operational simple procedure displays good functional group tolerance and avoids treatment of typically known offensive isocyanides. 相似文献
998.
Jing Liu Lin Zhou Ji‐Hong Chen Wang Mao Wen‐Jian Li Wei Hu Shu‐Yang Wang Chun‐Ming Wang 《Photochemistry and photobiology》2014,90(3):615-621
This study aimed to investigate the tolerance of a melanized wild‐type strain of Aspergillus niger (CON1) and its light‐colored mutant (MUT1) to UV–C light and the concomitantly generated ozone. Treatments were segregated into four groups based on whether UV irradiation was used and the presence or absence of ozone: (?UV, ?O3), (?UV, +O3), (+UV, ?O3) and (+UV, +O3). The survival of CON1 and MUT1 conidia under +UV decreased as the exposure time increased, with CON1 showing greater resistance to UV irradiation than MUT1. Ozone induced CON1 conidium inactivation only under conditions of UV radiation exposure. While, the inactivation effect of ozone on MUT1 was always detectable regardless of the presence of UV irradiation. Furthermore, the CON1 conidial suspension showed lower UV light transmission than MUT1 when examined at the same concentration. Compared with the pigment in MUT1, the melanin in CON1 exhibited more potent radical‐scavenging activity and stronger UV absorbance. These results suggested that melanin protected A. niger against UV disinfection via UV screening and free radical scavenging. The process by which UV–C disinfection induces a continual decrease in conidial survival suggests that UV irradiation and ozone exert a synergistic fungicidal effect on A. niger prior to reaching a plateau. 相似文献
999.
使用异构三联苯-2,2″,4,4″-四羧酸配体(m-H4tpta和p-H4tpta),通过水热法合成了2例新的单水桥Co (Ⅱ)/Ni (Ⅱ)金属链状配位聚合物[Co (m-H2tpta)(H2O)3]n(1)和{[Ni2(p-tpta)(H2O)6]·2H2O}n(2)。其结构通过FT-IR、元素分析、X射线单晶及粉末衍射进行了表征。在结构上,金属离子呈现出轻微扭曲的八面体几何构型,通过单水分子桥连接形成了一维金属链,异构H4tpta配体分别采用μ1-η1∶η0∶η1∶η0和μ4-η1∶η1∶η1∶η1配位模式与金属离子连接,形成一维链和三维网状结构,配合物2表现出(4,4)-连接的NbO型的三维拓扑网络结构。磁性方面,配合物1的Co(Ⅱ)离子间通过μ2-H2O桥传递表现出反铁磁相互作用。配合物2也展现出Ni(Ⅱ)离子间的反铁磁耦合作用,与磁耦合Ni—Ow—Ni角有关。 相似文献
1000.
Dr. Man‐Sheng Chen Xiong‐Wen Tan Dr. Chun‐Hua Zhang Dai‐Zhi Kuang 《无机化学与普通化学杂志》2011,637(9):1220-1223
A new three‐dimensional (3D) porous framework [Zn(INAIP)] · DMA · H2O ( 1 ) [INAIP = 5‐(isonicotinamido)isophthalate, DMA = N,N′‐dimethylacetamide] was synthesized by solvothermal methods and characterized by single‐crystal and powder X‐ray diffraction, as well as thermogravimetric analysis. The results of X‐ray diffraction analyses revealed that complex 1 has an unusual 3D architecture with the (3,6)‐connected rutile ( rtl ) topology. The adsorption behavior shows that compound 1 exhibits selective adsorptions of CO2 over N2 after the removal of the solvent molecules within the pores. 相似文献