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991.
Sampling inequalities give a precise formulation of the fact that a differentiable function cannot attain large values if
its derivatives are bounded and if it is small on a sufficiently dense discrete set. Sampling inequalities can be applied
to the difference of a function and its reconstruction in order to obtain (sometimes optimal) convergence orders for very
general possibly regularized recovery processes. So far, there are only sampling inequalities for finitely smooth functions,
which lead to algebraic convergence orders. In this paper, the case of infinitely smooth functions is investigated, in order
to derive error estimates with exponential convergence orders. 相似文献
992.
Stefan Egli Barbara Fischer Sonja Hartmann Patrick Hunziker Wolfgang Meier Per Rigler 《Macromolecular Symposia》2010,296(1):278-285
Here we present a novel strategy for specific cellular targeting of polymeric nanocontainers by using self-assembly of block copolymers consisting of either Polydimethoxysiloxane-b-Polymethyloxazoline-b-Polydimethoxysiloxane (PDMS-b-PMOXA-b-PDMS) or functionalized PDMS-b-PMOXA-b-PDMS. Covalent functionalization of the above copolymer was accomplished using either the fluorescent dye sulforhodamine B or a poly-guanosin ligand, the latter by using the Huisgen 1,3-dipolar cycloaddition. The success of the covalent modification of the block copolymer has been determined by studying functionalized sulforhodamine B by NMR and fluorescence correlation spectroscopy. The covalent click chemistry approach leads to efficiently functionalized polymeric nanocontainers which enables specific uptake by activated macrophages overexpressing the scavenger receptor A1. 相似文献
993.
Gaurav S. J. B. Rana Timothy P. York Jeffery S. Edmiston Barbara K. Zedler Joel G. Pounds Joshua N. Adkins Richard D. Smith Zaigang Liu Guoya Li Bradley T. Webb Edward L. Murrelle Jason W. Flora 《Analytical and bioanalytical chemistry》2010,397(5):1809-1819
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of morbidity and mortality in the United States and cigarette smoking is a primary determinant of the disease. COPD is characterized by chronic airflow limitation as measured by the forced expiratory volume in one second (FEV1). In this study, the plasma proteomes of 38 middle-aged or older adult smokers with mild to moderate COPD, with FEV1 decline characterized as either rapid (RPD, n?=?20) or slow or absent (SLW, n?=?18), were interrogated using a comprehensive high-throughput proteomic approach, the accurate mass and time (AMT) tag technology. This technology is based upon a putative mass and time tag database (PMT), high-resolution LC separations and high mass accuracy measurements using FT-ICR MS with a 9.4-T magnetic field. The peptide and protein data were analyzed using three statistical approaches to address ambiguities related to the high proportion of missing data inherent to proteomic analysis. The RPD and SLW groups were differentiated by 55 peptides which mapped to 33 unique proteins. Twelve of the proteins have known roles in the complement or coagulation cascade and, despite an inability to adjust for some factors known to affect lung function decline, suggest potential mechanistic biomarkers associated with the rate of lung function decline in COPD. Whether these proteins are the cause or result of accelerated decline will require further research. 相似文献
994.
Romani A Vignolini P Tanini A Pampaloni B Heimler D 《Natural product communications》2010,5(11):1775-1780
Isoflavones are polyphenolic compounds found mainly in legumes the benefits of which have been widely studied and attributed in particular to their phytoestrogenic activity. The aim of this study was to evaluate the quali-quantitative composition of food supplements based on soy isoflavones (Glycine max L.) and red clover (Trifolium pratense). Six commercial food supplements (five soy-based and one red clover-based) were analyzed by HPLC/DAD/MS. Genistein, daidzein, glycitein, biochanin A and formononetin derivatives (glycosides and acylglycosides) were identified in the analyzed samples. Also the antiradical activities (towards the DPPH* radical) and Fe2+ chelating abilities were compared. 相似文献
995.
The Julia-Kocienski olefination provides a versatile platform for the synthesis of fluorovinyl compounds. This review describes our efforts as well as those of others in the synthesis of various fluorinated aryl and heteroaryl sulfones and their utility as olefination reagents for the modular assembly of fluoroalkenes. Where data is available, the influence of the fluorine atom on the reactivity of the olefination reagents and the stereochemical outcome of the olefination are described. 相似文献
996.
Joël Brugger Allan Pring Frank Reith Chris Ryan Barbara Etschmann Weihua Liu Brian O’Neill Yung Ngothai 《Radiation Physics and Chemistry》2010,79(2):151-161
The understanding of the physico-chemical processes leading to the formation and weathering of ore deposits plays an increasingly important role in mineral exploration. Synchrotron, neutron, and nuclear radiation are contributing to this endeavour in many ways, including (i) support the modelling of ore transport and deposition, by providing molecular-level understanding of solvent–solute interaction and thermodynamic properties for the important metal complexes in brines, vapours, and supercritical fluids over the range of conditions relevant for the formation of ore deposits (i.e., temperature 25–600 °C; pressure 1–109 Pa; and fluid compositions varying from hypersaline (e.g., >50 wt% NaCl) to volatile-rich (e.g., CO2, CH4, and H2S)); (ii) track the fluids that travelled through rocks and predict their ore-forming potential by analysing hydrothermal minerals and remnants of those fluids trapped in these minerals as ‘fluid inclusions’; (iii) characterize the biochemical controls on metal mobility in soils to predict the geochemical footprint of a buried mineral deposit.X-ray fluorescence (XRF), particle-induced X-ray emission (PIXE), and X-ray absorption spectroscopy (XAS) are the most common techniques used in support of mineral exploration. Analytical challenges are related to (i) the complexity of heterogeneous natural samples, which often contain only low concentrations of the elements of interest; (ii) beam sensitivity, especially for redox-sensitive elements in aqueous fluids or biological samples; (iii) extreme sample environments, e.g., in-situ study of fluids at high pressure and temperature. Thus, critical improvements need to be made on a number of fronts to: (i) develop more efficient detectors, able to map large areas in heterogeneous samples (e.g., 106–108 pixels per map), and also to collect a maximum number of photons to limit sample exposure and beam damage; (ii) integrate techniques (e.g., XRF, XAS, and X-ray diffraction (XRD)) on a single beamline, and promote synergy between neutron-, synchrotron-, and nuclear microprobe-based methods; (iii) advance the theory (e.g., quantitative XANES interpretation; X-ray extended range technique (XERT) measurements) to gain maximum information from the hard-won datasets. 相似文献
997.
Wang XB Woo HK Jagoda-Cwiklik B Jungwirth P Wang LS 《Physical chemistry chemical physics : PCCP》2006,8(37):4294-4296
NaSO(4)(-)(H(2)O)(n) (n = 0-4) clusters have been generated in the gas phase as model systems to simulate the first dissolution steps of sulfate salts in water; photoelectron spectroscopy and theoretical calculations indicate that the first three water molecules strongly interact with both Na(+) and SO(4)(2-), forming a three-water solvation ring to start to pry apart the Na(+)SO(4)(2-) contact ion pair. 相似文献
998.
Nissenson P Knox CJ Finlayson-Pitts BJ Phillips LF Dabdub D 《Physical chemistry chemical physics : PCCP》2006,8(40):4700-4710
While there is increasing evidence for unique chemical reactions at interfaces, there are fewer data on photochemistry at liquid-vapor junctions. This paper reports a comparison of the photolysis of molybdenum hexacarbonyl, Mo(CO)(6), in 1-decene either as liquid droplets or in bulk-liquid solutions. Mo(CO)(6) photolysis is faster by at least three orders of magnitude in the aerosols than in bulk-liquids. Two possible sources of this enhancement are considered: (1) increased light intensity due to either Morphology-Dependent Resonances (MDRs) in the spherical aerosol particles and/or to increased pathlengths for light inside the droplet due to refraction, which are termed physical effects in this paper; and (2) interface effects such as an incomplete solvent-cage at the gas-liquid boundary and/or enhanced interfacial concentrations of Mo(CO)(6), which are termed chemical effects. Quantitative calculations of the first possibility were carried out in which the light intensity distribution in the droplets averaged over 215-360 nm was obtained for 1-decene droplets. Calculations show that the average increase in light intensity over the entire droplet is 106%, with an average increase of 51% at the interface. These increases are much smaller than the observed increase in the apparent photolysis rate of droplets compared to the bulk. Thus, chemical effects, i.e., a decreased solvent-cage effect at the interface and/or enhancement in the surface concentration of Mo(CO)(6), are most likely responsible for the dramatic increase in the photolysis rate. Similar calculations were also carried out for broadband (290-600 nm) solar irradiation of water droplets, relevant to atmospheric conditions. These calculations show that, in agreement with previous calculations by Mayer and Madronich [B. Mayer and S. Madronich, Atmos. Chem. Phys., 2004, 4, 2241] MDRs produce only a moderate average intensity enhancement relative to the corresponding bulk-liquid slabs when averaged over a range of wavelengths characteristic of solar radiation at the Earth's surface. However, as in the case of Mo(CO)(6) in 1-decene, chemical effects may play a role in enhanced photochemistry at the aerosol-air interface for airborne particles. 相似文献
999.
Liu J Williams BA Gwirtz RM Wold BJ Quake S 《Angewandte Chemie (International ed. in English)》2006,45(22):3618-3623
1000.
Haynes RK Fugmann B Stetter J Rieckmann K Heilmann HD Chan HW Cheung MK Lam WL Wong HN Croft SL Vivas L Rattray L Stewart L Peters W Robinson BL Edstein MD Kotecka B Kyle DE Beckermann B Gerisch M Radtke M Schmuck G Steinke W Wollborn U Schmeer K Römer A 《Angewandte Chemie (International ed. in English)》2006,45(13):2082-2088