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排序方式: 共有256条查询结果,搜索用时 15 毫秒
111.
112.
Basu Rahul Ramakrishnan Sriram Clausen Edgar C. Gaddy James L. 《Applied biochemistry and biotechnology》1994,(1):499-508
Chlorobium thiosulfatophilum may be used for the bioconversion of hydrogen sulfide to elemental sulfur or sulfate. Sulfur is the preferred product because
of problems in the disposal of sulfate. A CSTR with a sulfur-settling separator has been used to preferentially produce and
recover elemental sulfur. The simple nutritional requirements of the bacterium and differences in densities and average cell
and sulfur particle sizes make a CSTR with a sulfur-settling separator attractive. A bench-scale study has been carried out
to determine the optimum process conditions to maximize H2S conversion, cell growth, elemental sulfur production, and to minimize sulfate production. The liquid effluent typically
contained about 425–550 mg/L elemental sulfur. The sulfate concentration was maintained at levels below 100 mg/L. It was possible
to remove up to 57 Μmol min−1 L−1 of H2S from the gas stream. An experiment over a period of 392 h showed stable performance.
For Presentation at the Fifteenth Symposium on Biotechnology for Fuels and Chemicals, Colorado Springs, CO. 相似文献
113.
Do-Min Lee Gullapalli Kumaraswamy Kee-In Lee 《Monatshefte für Chemie / Chemical Monthly》2009,14(4):73-78
Abstract
Catalytic transfer hydrogenation of α-tosyloxyarylketones mediated by a chiral rhodium complex using an azeotropic mixture of formic acid/triethylamine afforded the corresponding 1-arylethanediol monotosylates in excellent yield with high enantioselectivity. 相似文献114.
Avinash Kumar Vijay Kumar S Sandip Gurav Mohd Zainuddin Purushottam Dewang Raghava Reddy Kethiri Sriram Rajagopal Ramesh Mullangi 《Biomedical chromatography : BMC》2013,27(12):1590-1594
A novel, simple, specific, sensitive and reproducible high‐performance liquid chromatography assay method has been developed and validated for the estimation of Orteronel in rat plasma. The bioanalytical procedure involves extraction of Orteronel and phenacetin (internal standard) from rat plasma with a simple liquid–liquid extraction process. The chromatographic analysis was performed on a Waters Alliance system using a gradient mobile phase conditions at a flow rate of 1 mL/min and a C18 column maintained at ambient room temperature. The eluate was monitored using a photodiode array detector set at 242. Orteronel and internal standard eluted at 4.8 and 6.2 min, respectively and the total run time was 9 min. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 100–3149 ng/mL (r2 = 0.995). The intra‐ and inter‐day precisions were in the ranges of 0.31–7.87 and 3.97–6.35, respectively, in rat plasma. The validated HPLC method was successfully applied to a pharmacokinetic study of Orteronel in rats. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
115.
K C Kumara Swamy S Kumaraswamy P Kommana 《Journal of the American Chemical Society》2001,123(50):12642-12649
Very short C-H...O, N-H...O, and O-H...O hydrogen bonds have been generated utilizing the cyclic phosphate [CH2(6-t-Bu-4-Me-C6H2O)2]P(O)OH (1). X-ray structures of (i) 1 (unsolvated, two polymorphs), 1...EtOH, and 1...MeOH, (ii) [imidazolium](+)[CH2(6-t-Bu-4-Me-C6H2O)2PO2](-)...MeOH [2], (iii) [HNC5H4-N=N-C5H4NH](2+)[(CH2(6-t-Bu-4-Me-C6H2O)2PO2)2](2-)...4CH3CN...H2O [3], (v) [K, 18-crown-6](+)[(CH2(6-t-Bu-4-Me-C6H2O)2P(O)OH)(CH2(6-t-Bu-4-Me-C6H2O)2PO2)](-)...2THF [4], (vi) 1...cytosine...MeOH [5], (vii) 1...adenine...1/2MeOH [6], and (viii) 1...S-(-)-proline [7] have been determined. The phosphate 1 in both its forms is a hydrogen-bonded dimer with a short O-H...O distance of 2.481(2) [triclinic form] or 2.507(3) A [monoclinic form]. Compound 2 has a helical structure with a very short C-H...O hydrogen bond involving an imidazolyl C-H and methanol in addition to N-H...O hydrogen bonds. A helical motif is also seen in 5. In 3, an extremely short N-H...O hydrogen bond [N...O 2.558(4) A] is observed. Compounds 6 and 7 also exhibit short N-H...O hydrogen bonds. In 1...EtOH, a 12-membered hydrogen-bonded ring motif, with one of the shortest known O-H...O hydrogen bonds [O...O 2.368(4) A], is present. 1...MeOH is a similar dimer with a very short O(-H)...O bond [2.429(3) A]. In 4, the deprotonated phosphate (anion) and the parent acid are held together by a hydrogen bond on one side and a coordinate/covalent bond to potassium on the other; the O-H...O bond is symmetrical and very strong [O...O 2.397(3) A]. 相似文献
116.
Pabbaraja Srihari Boyapelly Kumaraswamy Gokada Maheswara Rao Jhillu Singh Yadav 《Tetrahedron: Asymmetry》2010,21(1):106-111
The first stereoselective total synthesis of the nonenolide (?)-stagonolide A is described. Olefin metathesis and epoxide opening reaction are the key steps involved. 相似文献
117.
Suresh P S Abhishek Dixit Sanjeev Giri Sriram Rajagopal Ramesh Mullangi 《Biomedical chromatography : BMC》2013,27(4):496-501
A highly sensitive and rapid bioanalytical method has been developed and validated for the estimation of indomethacin in rat plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive‐ion mode. The assay procedure involves a simple liquid–liquid extraction of indomethacin and phenacetin (internal standard, IS) from rat plasma with acetonitrile. Chromatographic separation was achieved with 0.2% formic acid–acetonitrile (25:75, v/v) at a flow rate of 0.60 mL/min on an Atlantis dC18 column with a total run time 3.0 min. The MS/MS ion transitions monitored were 357.7 → 139.1 for indomethacin and 180.20 → 110.10 for IS. Method validation and pharmacokinetic study plasma analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.51 ng/mL and the linearity was observed from 0.51 to 25.5 ng/mL. The intra‐ and inter‐day precisions were in the range of 1.00–10.2 and 5.88–9.80%, respectively. This novel method has been applied to an oral pharmacokinetic study in rats. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
118.
119.
Rekulapally Sriram Chebolu Naga Sesha Sai Pavan Kumar Nerella Raghunandan Vadla Ramesh 《合成通讯》2013,43(23):3419-3428
Abstract A simple and efficient method is described for the oxidation of 7-azaindoles and indoles to 7-azaisatins and isatins using pyridinium chlorochromate–silica gel (PCC-SiO2) with the aid of Lewis acid catalyst aluminium chloride (AlCl3) in dichloroethane. Simplicity of the reaction conditions, easy workup procedure, and good yields are the key features of this protocol. 相似文献
120.
A unified enantioselective route is developed for the synthesis of heptadeca-1-ene-4,6-diyne-3S,8R,9S,10S-tetrol and its synthetic congeners. A proline-catalyzed aminoxylation, cross-metathesis, Wittig reaction, and catalytic dihydroxylation are key steps of this synthesis. This new approach is envisioned to facilitate the synthesis of every representative member of the family with skeletal and stereochemical variation. 相似文献