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51.
An analysis is carried out to study the flow and heat transfer characteristics in a second grade fluid over a stretching sheet with prescribed surface temperature including the effects of frictional heating, internal heat generation or absorption, and work due to deformation. In order to solve the fourth-order non-linear differential equation, associated with the flow problem, a fourth boundary condition is augmented and a proper sign for the normal stress modulus is used. It is observed that for a physical flow problem the solution is unique. The solutions for the temperature and the heat transfer characteristics are obtained numerically and presented by a table and graphs. Furthermore, it is shown that the heat flow is always from the stretching sheet to the fluid. 相似文献
52.
Reactions of the dichloroboryl complex of osmium, Os(BCl2)Cl(CO)(PPh3)2, with water, alcohols, and amines: Crystal structures of Os[B(OH)2]Cl(CO)(PPh3)2, Os[B(OEt)2]Cl(CO)(PPh3)2, and
George R. Clark Geoffrey J. Irvine Warren R. Roper L. James Wright 《Journal of organometallic chemistry》2003,680(1-2):81
Reaction between the dichloroboryl complex, Os(BCl2)Cl(CO)(PPh3)2, and water replaces both chloride substituents on the boryl ligand, without cleavage of the Os---B bond, giving yellow Os[B(OH)2]Cl(CO)(PPh3)2 (1). Compound 1 can be regarded as an example of a ‘metalla–boronic acid’ (LnM---B(OH)2) and in the solid state, X-ray crystal structure determination reveals that molecules of 1 are tetragonal pyramidal in geometry (Os---B, 2.056(3) Å) and are arranged in pairs, as hydrogen-bonded dimers. This same arrangement is found in the crystalline state for simple boronic acids. Reaction between the dichloroboryl complex, Os(BCl2)Cl(CO)(PPh3)2, and methanol and ethanol produces yellow Os[B(OMe)2]Cl(CO)(PPh3)2 (2a) and yellow Os[B(OEt)2]Cl(CO)(PPh3)2 (2b), respectively. The crystal structure of 2b reveals a tetragonal pyramidal geometry with the diethoxyboryl ligand in the apical site and with an Os---B bond distance of 2.081(5) Å. Reaction between Os(BCl2)Cl(CO)(PPh3)2, and N,N′-dimethyl-o-phenylenediamine and N,N′-dimethyl-ethylenediamine produces yellow
(5) and yellow
(6), respectively. Compounds 1, 2a, 2b, 5, and 6 all react with carbon monoxide to give the colourless, six-coordinate complexes Os[B(OH)2]Cl(CO)2(PPh3)2 (3), Os[B(OMe)2]Cl(CO)2(PPh3)2 (4a), Os[B(OEt)2]Cl(CO)2(PPh3)2 (4b),
(7), and
(8), respectively, but in the case of 6 only, this CO uptake is easily reversible. The crystal structure of 5 is also reported. 相似文献
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53.
[OS(η2-CS2Me)(CO)2(PPH3)2]+ and [Ir(η2-CS2Me)Cl(CO)(PPh3)2)+ react with NaBH4 giving OsH(CS2Me)(CO)2(PPh3)2 and IrH(CS2Me)Cl(CO)(PPh3)2 respectively; These compounds contain mutually hydride and η1-dithiomethylester ligands and upon heating undergo 1,2-elimination of MeSH producing Os(CS)(CO)2(PPh3)2 and IrCl(CS)(PPh3)2. 相似文献
54.
An energy-dependent phase-shift analysis of 0–21 MeV n-α scattering is presented and compared to the previous 0–23 MeV p-α analysis. The error matrix and inverse error matrix for both the n-α and the p-α analyses are given. 相似文献
55.
56.
Caddell JM Chapman AM Cooley BE Downey BP LeBlanc MP Jackson MM O'Connell TM Phung HM Roper TD Xie S 《The Journal of organic chemistry》2004,69(9):3212-3215
A convergent synthesis of adenosine A2a agonist 1 in the form of its maleate salt 2 was achieved. The key step in this approach was the highly selective 9beta-glycosylation reaction between 2-haloadenines or an N(2)-alkyl-6-chloroguanine and a D-ribose derivative containing a 2-ethyltetrazolyl moiety. Glycosylations of other purine derivatives were also examined, and the methods developed provide efficient access to a variety of adenosine analogues such as 2-alkylaminoadenosines, an attractive class of compounds with antiinflammatory activity. 相似文献
57.
Free fatty acid (FFA) compositions are examined in feedstock for biodiesel production, as source-specific markers in soil, and because of their role in cellular signaling. However, sample preparation of FFAs for gas chromatography-mass spectrometry (GC-MS) analysis can be time and labor intensive. Therefore, to increase sample preparation throughput, a glass microfluidic device was developed to automate derivatization of FFAs to fatty acid methyl esters (FAMEs). FFAs were delivered to one input of the device and methanolic-HCl was delivered to a second input. FAME products were produced as the reagents traversed a 29 μL reaction channel held at 55 °C. A Design of Experiment protocol was used to determine the combination of derivatization time (T(der)) and ratio of methanolic-HCl:FFA (R(der)) that maximized the derivatization efficiencies of tridecanoic acid and stearic acid to their methyl ester forms. The combination of T(der) = 0.8 min and R(der) = 4.9 that produced optimal derivatization conditions for both FFAs within a 5 min total sample preparation time was determined. This combination of T(der) and R(der) was used to derivatize 12 FFAs with a range of derivatization efficiencies from 18% to 93% with efficiencies of 61% for tridecanoic acid and 84% for stearic acid. As compared to a conventional macroscale derivatization of FFA to FAME, the microfluidic device decreased the volume of methanolic-HCl and FFA by 20- and 1300-fold, respectively. The developed microfluidic device can be used for automated preparation of FAMEs to analyze the FFA compositions of volume-limited samples. 相似文献
58.
Conway GD Borba DN Alper B Bartlett DV Gormezano C von Hellermann MG Maas AC Parail VV Smeulders P Zastrow KD 《Physical review letters》2000,84(7):1463-1466
Correlation of density turbulence suppression and reduced plasma transport is observed in the internal transport barrier (ITB) region of JET tokamak discharges with optimized magnetic shear. The suppression occurs in two stages. First, low frequency turbulence and ion transport are reduced across the plasma core by a toroidal velocity shear generated by intense auxiliary heating. Then with the ITB formation, high frequency turbulence and electron transport are reduced locally within the steep pressure gradient region of the ITB. 相似文献
59.
A high-yield synthesis of trans-RuCl2(CS)(H2O)(PPh3)2 from RuCl2(PPh3)3 and CS2 is described. The coordinated water molecule is labile, and introduction of CNR (R p-toyl or p-chlorophenyl) leads to yellow trans-RuCl2(CS)(CNR)(PPh3)2, which isomerises thermally to colourless cis-RuCl2(CS)(CNR)(PPh3)2. Reaction of AgClO4 with cis-RuCl2(CS)(CNR)(PPh3)2 gives [RuCl(CS)(CNR)(H2O)(PPh3)2]+, from which [RuCl(CS)(CO)(CNR)(PPh3)2]+ and [RuCl(CS)(CNR)2(PPh3)2]+ are derived. Reaction of trans-RuCl2(CS)(H2O)(PPh3)2 with sodium formate gives Ru(η2-O2CH)Cl(CS)(PPh3)2, which undergoes decarboxylation in the presence of (PPh3) to give RuHCl(CS)(PPh3)3. Ru(η2-O2CH)H(CS)(PPh3)2 and Ru(η2-O2CMe)-H(CS)(PPh3)2 are also described. 相似文献
60.
Seth Madren Will McElroy Kristin Schultz-Kuszak Boris Boumajny Yao Shu Sabine Sautter Helen C. Zhao Abby Schadock-Hewitt Chris Chumsae Nancy Ball Xiaoying Zhang Kimberly Rish Shukui Zhang Christine Wurm Sumin Cai Scott P. Bauer Cinzia Stella Laura Zheng Brian Roper David A. Michels Gang Wu Bostjan Kocjan Matej Birk Simon Erik Erdmann Xiaoping He Brad Whittaker Yvonne Song Hannah Barrett Kevin Strozyk Ye Jing Long Huang Vishal Mhatre Paul McLean Tiantian Yu Huijuan Yang Minna Mattila 《Electrophoresis》2022,43(9-10):1050-1058
An international team spanning 19 sites across 18 biopharmaceutical and in vitro diagnostics companies in the United States, Europe, and China, along with one regulatory agency, was formed to compare the precision and robustness of imaged CIEF (ICIEF) for the charge heterogeneity analysis of the National Institute of Standards and Technology (NIST) mAb and a rhPD-L1-Fc fusion protein on the iCE3 and the Maurice instruments. This information has been requested to help companies better understand how these instruments compare and how to transition ICIEF methods from iCE3 to the Maurice instrument. The different laboratories performed ICIEF on the NIST mAb and rhPD-L1-Fc with both the iCE3 and Maurice using analytical methods specifically developed for each of the molecules. After processing the electropherograms, statistical evaluation of the data was performed to determine consistencies within and between laboratory and outlying information. The apparent isoelectric point (pI) data generated, based on two-point calibration, for the main isoform of the NIST mAb showed high precision between laboratories, with RSD values of less than 0.3% on both instruments. The SDs for the NIST mAb and the rhPD-L1-Fc charged variants percent peak area values for both instruments are less than 1.02% across different laboratories. These results validate the appropriate use of both the iCE3 and Maurice for ICIEF in the biopharmaceutical industry in support of process development and regulatory submissions of biotherapeutic molecules. Further, the data comparability between the iCE3 and Maurice illustrates that the Maurice platform is a next-generation replacement for the iCE3 that provides comparable data. 相似文献