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991.
The present article describes the development of an analytical method for the determination of 13 perfluorinated alkyl substances (PFAS), as well as its application to real sewage sludge samples to confirm the presence of these compounds. The isolation of the analytes was performed by agitation, sonication and centrifugation techniques, followed by EnviCarb cleanup and weak anion exchange solid-phase extraction. Sensitive and selective determination was carried out by high-performance liquid chromatography?Ctandem mass spectrometry (HPLC-MS/MS). Six mass-labelled internal standards were used to ensure the accuracy of the analytical results following isotopic dilution method. Several mobile phases (acetonitrile, methanol, mixtures of both and water with ammonium acetate or acetic acid) have been tested to reach the best resolution and reproducibility results. Other parameters related to MS/MS conditions were optimized. The reliability of the method was confirmed by the evaluation of linearity (R 2?=?0.995?C0.999), accuracy (84?C99%) and injection repeatability and reproducibility (relative standard deviation below 19 and 23%, respectively). Limits of detection ranged from 0.007 to 2.217?pg. Recoveries show values higher than 80% for most of the target compounds. The application of this method to twenty real samples demonstrates its efficiency and accuracy, as well as provides for the first time to our knowledge, PFAS levels in sewage sludges from Spain. Figure
Relative composition of individual PFAS in sewage sludge. 相似文献
992.
993.
Lorenz C Hoffmann A Gross G Windhagen H Dellinger P Möhwald K Dempwolf W Menzel H 《Macromolecular bioscience》2011,11(2):234-244
A fast and simple approach for immobilization using copolymers as interlayers is reported. The synthesized copolymers form stable self-assembled layers on implant materials like, e.g., titanium in a simple coating/drying/washing sequence and have functional groups which can bind proteins from an aqueous solution. The copolymer films have been characterized via ellipsometry and contact angle measurements and were tested for biocompatibility. An immunoassay was used to determine the amount of BMP2 and demonstrated an approximately 10-fold increase as compared to previously used self-assembled monolayers. A BMP2-responsive cell line with luciferase detection was used to determine the biological activity of the bound signaling protein. 相似文献
994.
Tachi T Hase T Okamoto Y Kaji N Arima T Matsumoto H Kondo M Tokeshi M Hasegawa Y Baba Y 《Analytical and bioanalytical chemistry》2011,401(7):2301-2305
Microchip analysis is a promising method for therapeutic drug monitoring. This led us to evaluate a microchip-based fluorescence
polarization immunoassay (FPIA) system for point-of-care testing on patients being treated with theophylline. The sera were
collected from 20 patients being treated with theophylline. Fluorescence polarization was measured on the microchip and theophylline
concentrations in serum were obtained. Regression analysis of the correlations was done between the results given by the microchip-based
FPIA and the conventional cloned enzyme donor immunoassay (CEDIA), and between the results given by the microchip-based FPIA
and the conventional particle-enhanced turbidimetric inhibition immunoassay (PETINIA). We successfully carried out a quantitative
analysis of theophylline in serum at values near its therapeutic range in 65 s. The results obtained by the microchip-based
FPIA correlated well with CEDIA and PETINIA results; the correlation coefficients (R
2) were 0.986 and 0.989, respectively. The FPIA system is a simple and rapid method for point-of-care testing of drugs in serum,
and its accuracy is the same as the conventional CEDIA and PETINIA. It is essential to use real samples from patients and
to confirm good correlations with conventional methods for a study on the realization of microchip. 相似文献
995.
von Vacano B Xu R Hirth S Herzenstiel I Rückel M Subkowski T Baus U 《Analytical and bioanalytical chemistry》2011,400(7):2031-2040
By combining several surface analytical tools, we show that an adsorbed layer of the protein H*Protein B prevents the adsorption
of secondary proteins bovine serum albumin, casein, or collagen at low-salinity conditions and at pH 8. H*Protein B is an
industrially producible fusion protein of the hydrophobin family, known for its high interfacial activity. While applications
of hydrophobin have been reported to facilitate adhesion of proteins under different pH conditions, careful analysis by quartz-crystal
microbalance and ellipsometry prove that no additional adsorption can be found on top of the H*Protein B layer in this study.
Surface analysis by X-ray photoelectron spectroscopy and secondary ion mass spectrometry proves that the hydrophobin layer
stays intact even after hours of exposure to solutions of the secondary proteins and that no exchange of proteins can be detected. 相似文献
996.
Coussot G Perrin C Moreau T Dobrijevic M Le Postollec A Vandenabeele-Trambouze O 《Analytical and bioanalytical chemistry》2011,399(3):1061-1069
The covalent immobilization of synthetic or natural macromolecular compounds containing amino groups onto polystyrene (PS)
solid surfaces is of great interest in diagnostic applications. A sensitive assay allowing the determination of reactive end
groups is therefore a powerful tool for predicting the performance of the active surface. Recently, we reported the use of
the Coomassie brilliant blue (CBB) colorimetric reagent to quantify protonated groups (N+) in linear and dendritic structures in solution (Coussot et al., Polym Int 58(5):511–518, 2009). In this work, a simple method using CBB dye for the characterization of PS aminated solid surfaces is developed. The proposed
amino density estimation by colorimetric assay (ADECA) method is based on the reversible complexation of the dye with the
N+ groups on solid surfaces. The assay measures the released dye thanks to the use of a unique sodium carbonate–methanol buffer.
Thereby, for the first time, the same surface can be used for characterization and for further coupling applications. A surface
density of four N+ groups per square nanometer can be measured in PS microwell format, the whole characterization being done within 30 min.
Performances of this new colorimetric-based method are detailed. The ADECA method is further demonstrated to be useful for
the characterization of aminated polypropylene and glass materials with various sizes and shapes. 相似文献
997.
Møller C Sprenger RR Stürup S Højrup P 《Analytical and bioanalytical chemistry》2011,401(5):1623-1633
Using insulin as a model protein for binding of oxaliplatin to proteins, various mass spectrometric approaches and techniques
were compared. Several different platinum adducts were observed, e.g. addition of one or two diaminocyclohexane platinum(II)
(Pt(dach)) molecules. By top-down analysis and fragmentation of the intact insulin–oxaliplatin adduct using nano-electrospray
ionisation quadrupole time-of-flight mass spectrometry (nESI-Q-ToF-MS), the major binding site was assigned to histidine5
on the insulin B chain. In order to simplify the interpretation of the mass spectrum, the disulphide bridges were reduced.
This led to the additional identification of cysteine6 on the A chain as a binding site along with histidine5 on the B chain.
Digestion of insulin–oxaliplatin with endoproteinase Glu-C (GluC) followed by reduction led to the formation of five peptides
with Pt(dach) attached. Identification of several of the binding sites was obtained using matrix-assisted laser desorption/ionization
(MALDI)-ToF-ToF-MS and liquid chromatography-nESI-Q-ToF-MS. Upon comparing the top-down and bottom-up approaches, the suitability
of the bottom-up approach for determining binding sites was questioned, as the release and possible re-association of Pt(dach)
were demonstrated upon enzymatic digestion. The associated advantages and disadvantages of ESI and MALDI were also pointed
out. 相似文献
998.
999.
Hanć A Komorowicz I Iskra M Majewski W Barałkiewicz D 《Analytical and bioanalytical chemistry》2011,399(9):3221-3231
The study was aimed to evaluate the influence of the vascular disease, atherosclerotic obliterans (AO), on the location and
concentration of elements in the arterial wall and serum. Use of a modern method for studying element’s concentration and
distribution in samples of clinical material, i.e. laser ablation inductively coupled plasma mass spectrometry, is presented.
Elements are not equally distributed between the inner (intima) and the outer (media + adventitia) layer of the arterial wall.
Among the studied elements, calcium was found to have an unquestionable role in the calcification of the wall. Increased concentration
of calcium found in the inner part of the atherosclerotic arterial wall and in the plaque, as compared to the control arterial
wall samples, demonstrates the unquestionable role of this element in the calcification of the wall observed in AO. Applied
chemometric methods were useful for demonstrating the differences in the element’s concentration in blood serum and the arterial
wall samples between AO and the control group. 相似文献
1000.
Schroeder M Hogwood J Gray E Mulloy B Hackett AM Johansen KB 《Analytical and bioanalytical chemistry》2011,399(2):763-771
Protamine sulphate is an effective inhibitor of heparin and is used clinically to neutralise both low molecular weight heparins
(LMWH) and unfractionated heparin (UFH). However, protamine sulphate does not fully counter the anti-Xa effect of LMWH, even
in excess (>40 μg to 1 IU/ml). To investigate the molecular basis for this observation, the residual potencies in the presence
and absence of plasma as well as the molecular weight profiles of commercial LMWH neutralised with increasing amounts of protamine
were measured. Materials over 5000 Da are preferentially neutralised by protamine. To further investigate this molecular weight
dependence, monodisperse oligosaccharides were prepared from three commercial LMWHs. The specific anti-Xa activity for the
fractions increased with molecular weight, and was found to vary between the three preparations for oligosaccharides of the
same molecular weight. Our results indicate that protamine sulphate neutralisation is largely dependent on molecular weight,
leading to the implication that LMWHs containing a larger proportion of small oligosaccharides will not be as effectively
neutralised. Protamine sulphate neutralisation of any given LMWH is also affected by the specific anticoagulant activities
of its low molecular weight components, which varies between LMWH products, presumably with the method of manufacture. 相似文献