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71.
Zhantao Peng Bin Di Wentao Li Dan Liu Xiaojie Wen Hao Zhu Huanjun Song Yajie Zhang Cen Yin Xiong Zhou Kai Wu 《Angewandte Chemie (International ed. in English)》2020,59(34):14321-14325
Potassium (K) cations are spontaneously formed upon thermal deposition of low‐coverage K onto an ultrathin CuO monolayer grown on Cu(110) and they were explored by low‐temperature scanning tunneling microscopy (STM) and X‐ray photoemission spectroscopy. The formed K cations are highly immobile and thermally stable. The local work function around an individual K cation decreases by 1.5±0.3 eV, and a charging zone underneath it is established within about 1.0 nm. The cationic and neutral states of the K atom are switchable upon application of an STM bias voltage pulse, which is simultaneously accompanied by an adsorption site relocation. 相似文献
72.
Mahendra Patel Haamid Haroon Ajay Kumar Jahangir Ahmad Gulzar A. Bhat Dr. Saifullah Lone Dhanya Putthusseri Prof. Kowsar Majid Dr. Malik Wahid 《Chemphyschem》2020,21(8):814-820
We chose to understand the cyclic instability and rate instability issues in the promising class of Na+ conversion and alloying anodes with Sb2Se3 as a typical example. We employ a synthetic strategy that ensures efficient rGO (reduced graphene oxide) wrapping over Sb2Se3 material. By utilization of the minimum weight of additive (5 wt.% of rGO), we achieved a commendable performance with a reversible capacity of 550 mAh g−1 at a specific current of 100 mA g−1 and an impressive rate performance with 100 % capacity retention after high current cycling involving a 2 Ag−1 intermediate current step. The electrochemical galvanostatic intermittent titration technique (GITT) has been employed for the first time to draw a rationale between the enhanced performance and the increased mobility in the rGO wrapped composite (Sb2Se3-rGO) compared to bare Sb2Se3. GITT analysis reveals higher Na+ diffusion coefficients (approx. 30 fold higher) in the case of Sb2Se3-rGO as compared to bare Sb2Se3 throughout the operating voltage window. For Sb2Se3-rGO the diffusion coefficients in the range of 8.0×10−15 cm2 s−1 to 2.2×10−12 cm2 s−1 were observed, while in case of bare Sb2Se3 the diffusion coefficients in the range of 1.6×10−15 cm2 s−1 to 9.4×10−15 cm2 s−1 were observed. 相似文献
73.
粗碲是由铜、铅、锌冶炼带来的副产品,其中含有大量的金、银等贵金属。快速准确检测粗碲中银含量,具有十分重要的意义。样品预先采用硫酸溶解,还原沉淀金、银,过滤分离大部分的铋、硒、碲等元素,经配料、高温熔融,熔融态的金属铅捕集试料中的贵金属形成铅扣,试料的其他物质与熔剂生成易熔性熔渣。将铅扣灰吹,得金银合粒,清除合粒表面粘附的杂质,经硝酸分金,用硫氰酸钾滴定法测定银量。银的加标回收率在99.5%~101%,相对标准偏差(RSD)小于5%。方法速度快,稳定性好,适用于粗碲中银含量的测定。 相似文献
74.
Interaction of diethyl aniline methylphosphonate with DNA: Spectroscopic and isothermal titration calorimetry 总被引:1,自引:0,他引:1
In this study the diethyl aniline methylphosphonate (DAM) was synthesized, the interaction of DAM with ct-DNA has been investigated by fluorescence spectra, UV spectra, molecular modeling and isothermal titration calorimetry (ITC). The binding constant of DAM to ct-DNA calculated from both isothermal titration calorimetry and fluorescence spectra were found to be in the 104 M−1 range. According to the ethidium bromide displacement studies, UV spectra and isothermal titration calorimetry experimental results, it can be concluded that DAM is an intercalator that can slide into the G-C rich region of ct-DNA. Furthermore, the results obtained from molecular modeling corroborated the experimental results obtanied from spectroscopic and ITC investigations. At the same time, fluorescence spectra suggested that the mechanism of the interaction of DAM to ct-DNA was a static enhancing type. ITC data showed that ct-DNA/DAM binding is enthalpy controlled. 相似文献
75.
采用自动电位滴定法标定硫酸铈溶液,并进行硫酸亚铁片中铁含量的测定。自动电位滴定法以电位突跃监测终点,在45℃~50℃之间,以草酸钠溶液标定硫酸铈溶液,测定值的相对标准偏差(n=5)为0.070%。取硫酸亚铁片1片用0.01mol·L-1硫酸溶液30mL溶解,直接用硫酸铈溶液滴定测定铁含量。方法用于硫酸亚铁片样品分析,回收率为100%,测定值的相对标准偏差(n=5)在1.2%~2.6%之间。 相似文献
76.
Facile Synthesis of Dibenzopentalene Dianions and Their Application as New π‐Extended Ligands 下载免费PDF全文
Takuya Kuwabara Dr. Kazuya Ishimura Prof. Dr. Takahiro Sasamori Prof. Dr. Norihiro Tokitoh Prof. Dr. Masaichi Saito 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(25):7571-7575
Reduction of phenyl(silyl)ethynes with potassium followed by quenching with iodine gave dibenzopentalenes in moderate yields. The intermediates of the reactions, dipotassium dibenzopentalenides, were isolated. The first dibenzopentalene–transition‐metal complex was successfully synthesized. The ruthenium atoms are located above the six‐membered rings. However, X‐ray diffraction analysis and theoretical calculations revealed that the aromatic nature of the five‐membered rings was retained. The cyclic voltammetry of the Ru complex revealed two oxidation waves with relatively large separation. 相似文献
77.
David J. Liptrot Prof. Michael S. Hill Dr. Mary F. Mahon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9871-9874
Reactions between PhSiH3 and alkali‐metal diamidoalkylmagnesiates ([M{N(SiMe3)2}2MgBu], M=Li, Na, K) provide either selective alkyl metathesis or the formation of polyhydride aggregates contingent upon the identity of the Group 1 metal. In the case of [M{N(SiMe3)2}2MgBu], this reactivity results in a structurally unprecedented dodecametallic decahydride cluster species. 相似文献
78.
Unprecedented cyclization was observed during N-sulfonylation of 3-[1-(phenylhydrazono)-ethyl]-chromen-2-one in pyridine, affording 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones. To avoid use of noxious pyridine, reaction was tried in different basic conditions and the best results were obtained with potassium carbonate in acetone. A wide range of substrates bearing either electron-donating or electron-withdrawing substituents on phenylhydrazine ring were compatible with the developed methodology. Rapid access of starting material, 3-acetylcoumarin, excellent yields of products, and use of environmentally benign base and solvent for the cyclization make this strategy an efficient and convenient method for synthesis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones. 相似文献
79.
Filip Botha Jan Budka Václav Eigner Oldřich Hudeček Lukáš Vrzal Ivana Císařová Pavel Lhoták 《Tetrahedron》2014
A new type of calixarene-based receptor designed for the recognition of chiral anions was prepared by the introduction of (S)-2-methylbutan-1-ol moieties into the lower rim of calixarene. The immobilization of calixarene skeleton in the 1,3-alternate conformation enabled the construction of a cavity consisting of preorganised ureido functions and chiral substituents in close proximity. This cavity is capable of chiral discrimination of selected anions as demonstrated on d- and l-phenylalaninates. 相似文献
80.
The phenolic-group capacities of five humic substances, such as, the Aldrich humic acid, the humic and fulvic acids extracted from a soil, the humic and fulvic acids extracted from a peat have been precisely determined by the non-aqueous potentiometric titration technique. The titration by KOH in the mixed solvent of DMSO:2-propanol:water = 80:19.3:0.7 at [K+] = 0.02 M enabled to measure the potential change in a wide range of pOH (=−log [OH−]), and thus to determine the capacities of phenolic groups which could not be precisely determined in the aqueous titration. The results of the titration revealed that the mean protonation constants of the phenolic groups were nearly the same for all humic substances and close to that of phenol in the same medium, indicating that each phenolic-group in the humic substances is rather isolated and is not electronically affected by other affecting groups in the humic macromolecule. 相似文献