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351.
Mukesh Kumar Pankaj Kumar Anshu Agrawal Rajesh Kumar B. K. Sahoo 《Journal of Radioanalytical and Nuclear Chemistry》2017,313(1):39-45
A novel ethylene diamine tetraacetic acid derivative of 4-nitroimidazole (EDTA-4-EtNHNM) was successfully synthesized as a carrier molecule and it was radiolabeled with 99mTc in high yield to obtain 99mTc-EDTA-4-EtNHNM, which was hydrophilic and had good in vitro stability. The tumor cell experiment and the biodistribution study in mice bearing S180 tumor showed that this complex exhibited a hypoxic selectivity and had high accumulation in tumor tissue with major clearance through urinary tract. High tumor uptake and tumor/muscle ratio of the complex suggests promise towards further evaluation. 相似文献
352.
Efficient extraction of chemical warfare agents (CWAs) from water is essential before subjecting them to gas chromatographic and spectral analysis aiming towards verification of the Chemical Weapons Convention (CWC). It requires development of fast, reliable, simple and reproducible sample preparation of CWAs from water which is likely to be contaminated during deliberate or inadvertent spread of CWAs. This work describes development of a solid-phase extraction method using hydrophilic-lipophilic balance (HLB) cartridges for extraction of CWAs from water. The extraction efficiencies of HLB and C18 cartridges were compared and the results revealed that HLB sorbents performed better. Extracts were analyzed by gas chromatography-mass spectrometry. Extraction parameters, such as extraction solvent, its volume and rinsing solvent were optimized. Best recoveries of target analytes were obtained using 1mL methanol and limits of detection were achieved up to 0.05microg/mL with dichloromethane. Precision of the method was found to be less than 9.2% RSD. 相似文献
353.
Pardasani D Mazumder A Gupta AK Kanaujia PK Tak V Dubey DK 《Rapid communications in mass spectrometry : RCM》2007,21(18):3109-3114
Retrospective detection and identification of markers of chemical warfare agents are important aspects of verification of the Chemical Weapons Convention. Alkyl alkylphosphonic acids (AAPAs) and alkylphosphonic acids (APAs) are important markers of nerve agents. We describe the development and optimization of a new gas chromatography/mass spectrometry (GC/MS) injection port fluorination method for the derivatization of AAPAs and APAs. The process involved the injection of acids with trifluoroacetic anhydride in GC/MS, where acids are converted into their corresponding volatile fluorides. Various reaction conditions such as fluorinating agent, injection port temperature and splitless time were optimized. The maximum reaction efficiency of the acids with trifluoroacetic anhydride was observed at 230 degrees C injection port temperature with a splitless time of 2 min. APAs showed best analytical efficiencies at 400 degrees C injection port temperature, while the other conditions were similar to those of AAPAs. The linearities of response for APAs and AAPAs were in the range of 1-25 and 5-100 microg mL(-1), respectively, with limits of detection ranging from 500 pg to 800 ng mL(-1). 相似文献
354.
Ahmed SA Odde S Daga PR Bowling JJ Mesbah MK Youssef DT Khalifa SI Doerksen RJ Hamann MT 《Organic letters》2007,9(23):4773-4776
A new latrunculin, oxalatrunculin B (3), was isolated from Red Sea sponge Negombata corticata. Extensive spectroscopic analysis revealed an unprecedented heterocycle in which the rare thiazolidinone ring found in latrunculins was oxidized with three additional oxygens. An actin polymerization inhibition assay agreed with MM-PBSA free energy calculations that 3 binds more weakly than latrunculin B to actin. Significant antifungal and anticancer activity of 3 was found, suggesting an alternate target in addition to actin for latrunculin bioactivity. 相似文献
355.
Pathak P Prasad GL Meziani MJ Joudeh AA Sun YP 《Langmuir : the ACS journal of surfaces and colloids》2007,23(5):2674-2679
The rapid expansion of a supercritical solution into a liquid solvent (RESOLV) technique with benign supercritical carbon dioxide was applied to obtain aqueous suspended nanoparticles of the highly potent anticancer drug paclitaxel. The paclitaxel nanoparticles were protected from agglomeration by using a known nontoxic stabilization agent. The aqueous suspended paclitaxel nanoparticles of different average particle sizes were evaluated in vitro against human breast cancer cells. The results suggest that the nanosized paclitaxel particles are effective, with an antineoplastic activity comparable to that of the commercial paclitaxel formulation. The technique should be generally applicable to the processing of nanoparticles from other important drugs with aqueous solubility problems. 相似文献
356.
Ritika Singh Pramod K. Singh Shri Prakash Pandey Sunanda Kakroo Pankaj K. Tripathi Rohit Kumar Yashika Bajaj 《Macromolecular Symposia》2024,413(1):2300095
A high-conducting salt-doped polymer electrolyte layer has been created here for use in photocell technologies. The solution casting method is used to produce ion conducting film where poly (methyl methacrylate) (PMMA) is used as the host polymer and potassium iodide (KI) as the dopant. The conductivity and amorphic increases of the polymer electrolytes with the addition of salt concentrations helps in the enhancement of the charge transfer properties. Using electrochemical impedance spectroscopy (EIS), ionic conductivity is evaluated where maximum conductivity is 3.99 × 10−6 S cm-1 at 20 wt% KI concentration. Polarized optical microscopy (POM) shows the reduction in crystallinity by salt doping, while Fourier transforms infrared spectroscopy (FTIR) shows the complexation as well as composite nature of the film. Ionic transference number (tion) measurement shows the predominantly ionic nature of this polymer electrolyte. 相似文献
357.
358.
A series of triphenylarsenic(V) derivatives Ph3As(OPri)[SC6H4N:C(R)CH2C(O)R′] have been synthesized by the reactions of triphenylarsenic(V)‐ isoproproxide, Ph3As(OPri)2 with the corresponding 2,2‐disubstituted benzothiazolines of the type (where R = CH3, R′ = CH3( 1 ); R = CH3, R′ = C6H5( 2 ); R = CH3, R′ = 4‐CH3C6H4( 3 ); R = CH3, R′ = 4‐ClC6H4( 4 ); and R = CF3, R′ = C6H5( 5 )) in equimolar ratio in refluxing benzene solution. Molecular weight measurements of these complexes show their monomeric nature in solution. Characterization of these compounds using elemental analyses, molecular weight measurements, and spectral studies (IR as well as NMR (1H and 13C)) shows the monofunctional bidentate nature of the ligands and a hexacoordination around the central arsenic atom in these organoarsenic(V) derivatives. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:76–80, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20233 相似文献
359.
Sandip Das Kulbir Soumyadip Ray Tarali Devi Somnath Ghosh Sarvesh S. Harmalkar Sunder N. Dhuri Padmabati Mondal Pankaj Kumar 《Chemical science》2022,13(6):1706
Small molecule activation and their transfer reactions in biological or catalytic reactions are greatly influenced by the metal-centers and the ligand frameworks. Here, we report the metal-directed nitric oxide (NO) transfer chemistry in low-spin mononuclear {Co(NO)}8, [(12-TMC)CoIII(NO−)]2+ (1-CoNO, S = 0), and {Cr(NO)}5, ([(BPMEN)Cr(NO)(Cl)]+) (4-CrNO, S = 1/2) complexes. 1-CoNO transfers its bound NO moiety to a high-spin [(BPMEN)CrII(Cl2)] (2-Cr, S = 2) and generates 4-CrNOvia an associative pathway; however, we did not observe the reverse reaction, i.e., NO transfer from 4-CrNO to low-spin [(12-TMC)CoII]2+ (3-Co, S = 1/2). Spectral titration for NO transfer reaction between 1-CoNO and 2-Cr confirmed 1 : 1 reaction stoichiometry. The NO transfer rate was found to be independent of 2-Cr, suggesting the presence of an intermediate species, which was further supported experimentally and theoretically. The experimental and theoretical observations support the formation of μ-NO bridged intermediate species ({Cr–NO–Co}4+). Mechanistic investigations using 15N-labeled-15NO and tracking the 15N-atom established that the NO moiety in 4-CrNO is derived from 1-CoNO. Further, to investigate the factors deciding the NO transfer reactivity, we explored the NO transfer reaction between another high-spin CrII-complex, [(12-TMC)CrII(Cl)]+ (5-Cr, S = 2), and 1-CoNO, showing the generation of the low-spin [(12-TMC)Cr(NO)(Cl)]+ (6-CrNO, S = 1/2); however, again there was no opposite reaction, i.e., from Cr-center to Co-center. The above results advocate clearly that the NO transfer from Co-center generates thermally stable and low-spin and inert {Cr(NO)}5 complexes (4-CrNO & 6-CrNO) from high-spin and labile Cr-complexes (2-Cr & 5-Cr), suggesting a metal-directed NO transfer (cobalt to chromium, not chromium to cobalt). These results explicitly highlight that the NO transfer is strongly influenced by the labile/inert behavior of the metal-centers and/or thermal stability rather than the ligand architecture.Nitric oxide activation and parameters influencing intermolecular transfer of nitric oxide. 相似文献
360.
Pankaj S Joshi 《Pramana》2000,55(4):529-544
An outstanding problem in gravitation theory and relativistic astrophysics today is to understand the final outcome of an
endless gravitational collapse. Such a continual collapse would take place when stars more massive than few times the mass
of the sun collapse under their own gravity on exhausting their nuclear fuel. According to the general theory of relativity,
this results either in a black hole, or a naked singularity — which can communicate with far away observers in the universe.
While black holes are (almost) being detected and are increasingly used to model high energy astrophysical phenomena, naked
singularities have turned into a topic of active discussion, aimed at understanding their structure and implications. Recent
developments here are reviewed, indicating future directions. 相似文献