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991.
Eunseo Oh Ha Young Lee Hak Jung Kim Yoo Jung Park Jeong Kon Seo Joon Seong Park Yoe-Sik Bae 《Experimental & molecular medicine》2015,47(11):e194
When mouse bone marrow-derived macrophages were stimulated with serum amyloid A (SAA), which is a major acute-phase protein, there was strong inhibition of osteoclast formation induced by the receptor activator of nuclear factor kappaB ligand. SAA not only markedly blocked the expression of several osteoclast-associated genes (TNF receptor-associated factor 6 and osteoclast-associated receptor) but also strongly induced the expression of negative regulators (MafB and interferon regulatory factor 8). Moreover, SAA decreased c-fms expression on the cell surface via shedding of the c-fms extracellular domain. SAA also restrained the fusion of osteoclast precursors by blocking intracellular ATP release. This inhibitory response of SAA is not mediated by the well-known SAA receptors (formyl peptide receptor 2, Toll-like receptor 2 (TLR2) or TLR4). These findings provide insight into a novel inhibitory role of SAA in osteoclastogenesis and suggest that SAA is an important endogenous modulator that regulates bone homeostasis. 相似文献
992.
Influence of the β‐Sheet Content on the Mechanical Properties of Aggregates during Amyloid Fibrillization 下载免费PDF全文
Jae Sun Jeong Prof. Hilal A. Lashuel Prof. Raffaele Mezzenga Prof. Giovanni Dietler 《Angewandte Chemie (International ed. in English)》2015,54(8):2462-2466
Amyloid fibrils associated with neurodegenerative diseases, such as Parkinson’s and Alzheimer’s, consist of insoluble aggregates of α‐synuclein and Aβ‐42 proteins with a high β‐sheet content. The aggregation of both proteins occurs by misfolding of the monomers and proceeds through the formation of intermediate oligomeric and protofibrillar species to give the final fibrillar cross‐β‐sheet structure. The morphological and mechanical properties of oligomers, protofibrils, and fibrils formed during the fibrillization process were investigated by thioflavin T fluorescence and circular dichroism in combination with AFM peak force quantitative nanomechanical technique. The results reveal an increase in the Young’s modulus during the transformation from oligomers to mature fibrils, thus inferring that the difference in their mechanical properties is due to an internal structural change from a random coil to a structure with increased β‐sheet content. 相似文献
993.
Hong-Seok Kim Dong-Hyun Kim Ki Soo Kim Heung-Jin Choi Jun Ho Shim In Seok Jeong Geun Sig Cha Hakhyun Nam 《Journal of inclusion phenomena and macrocyclic chemistry》2003,46(3-4):201-205
The synthesis, spectroscopic characterization, and potentiometricmeasurements of new 1,3,5-trisphenoxy-2,4,6-triethylbenzenesare described. The cation binding abilities oftrisphenoxy-2,4,6-triethylbenzenes were strongly dependenton the substituents introduced on the phenoxy units: thereceptors with electron-donating alkoxy groups (–OCH3and –OCH2C6H5) provided similar potentiometricperformance to that of nonactin in PVC-based, ion-selectivemembrane electrodes. The trisphenoxy-2,4,6-triethylbenzenereceptors with ether groups on ortho and meta positions ofphenoxy units exhibit almost identical cation recognitionproperties in the PVC membranes. It is postulated that theelectron-donating nature of the alkoxy substituents increases theelectron density in the phenoxy units, resulting in increasedcation- interactions. 相似文献
994.
Irreversible inhibition of CD13/aminopeptidase N by the antiangiogenic agent curcumin 总被引:3,自引:0,他引:3
Shim JS Kim JH Cho HY Yum YN Kim SH Park HJ Shim BS Choi SH Kwon HJ 《Chemistry & biology》2003,10(8):695-704
CD13/aminopeptidase N (APN) is a membrane-bound, zinc-dependent metalloproteinase that plays a key role in tumor invasion and angiogenesis. Here, we show that curcumin, a phenolic natural product, binds to APN and irreversibly inhibits its activity. The direct interaction between curcumin with APN was confirmed both in vitro and in vivo by surface plasmon resonance analysis and an APN-specific antibody competition assay, respectively. Moreover, curcumin and other known APN inhibitors strongly inhibited APN-positive tumor cell invasion and basic fibroblast growth factor-induced angiogenesis. However, curcumin did not inhibit the invasion of APN-negative tumor cells, suggesting that the antiinvasive activity of curcumin against tumor cells is attributable to the inhibition of APN. Taken together, our study revealed that curcumin is a novel irreversible inhibitor of APN that binds to curcumin resulting in inhibition of angiogenesis. 相似文献
995.
A facile method for the transition-metal-free diarylation of isocyanates with arynes in the presence of cesium fluoride has been developed, which affords functionalized diaryl amines in moderate to excellent yields. This reaction has good functional group tolerance and provides excellent regioselectivity by utilizing a methoxy-substituted aryne precursor. 相似文献
996.
A series of late transition metal complexes, [(bpma)Co(μ – Cl)Cl] 2 , [(bpma)Cu(μ – Cl)Cl] 2 , [(bpma)Zn(μ – Cl)Cl] 2 and [(bpma)Cd(μ – Br)Br] 2 (where bpma is 4‐bromo‐N‐((pyridin‐2‐yl)methylene)benzenamine) have been synthesized and structurally characterized. The X‐ray structures of dimeric complexes [(bpma)M(μ – X)X] 2 (M = Co, Cu and Zn, X = Cl; M = Cd, X = Br) showed a distorted 5‐coordinate trigonal bipyramidal geometry involving two nitrogen atoms of N,N‐bidentate ligand, two bridged and one terminal halogen atoms. The complex [(bpma)Cu(μ – Cl)Cl] 2 revealed the highest catalytic activity for the polymerisation of methyl methacrylate in the presence of modified methylaluminoxane with an activity of 9.14 × 104 g PMMA/mol·Cu·h at 60 °C and afforded syndiotactic poly (methylmethacrylate) (rr = 0.69). 相似文献
997.
Soo‐Young Jeong Hae Won Jang Trishna Debnath Kwang‐Geun Lee 《Journal of separation science》2019,42(5):1012-1018
In this study, an automated solid‐phase microextraction coupled with gas chromatography and mass spectrometry method was developed and validated for the determination of furan in eight matrices including ham, milk, apple juice, rice porridge, peanut butter, flatfish, tuna (canned) and seaweed. The calibration curves were highly linear (r2 > 0.990) and the limit of detection and limit of quantification ranged from 0.01?0.02 and 0.04?0.06 ng/g, respectively. The recovery ranged from 77.81?111.47%. The validated method was used to analyse the furan levels in 120 foods. The highest levels of furan were detected in black tea (172.05 ng/g) and red ginseng extract (89.27 ng/g). Whelk (canned) contained a high furan content (21.34 ng/g) among the seafood samples. 相似文献
998.
Weijia Zheng Kyung‐Hee Yoo Jeong‐Min Choi Da‐Hee Park Seong‐Kwan Kim Young‐Sun Kang A. M. Abd El‐Aty Ahmet Hacmüftüolu Jing Wang Jae‐Han Shim Ho‐Chul Shin 《Biomedical chromatography : BMC》2019,33(1)
In the present study, we aimed to develop a reliable screening method based on liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) for the detection and quantification of naproxen, methyltestosterone and 17α‐hydroxyprogesterone caproate residues. The target analytes were extracted from samples of eel, flatfish and shrimp using acetonitrile with 1% acetic acid, followed by liquid–liquid purification with n‐hexane. Chromatographic separation was achieved on a reversed‐phase analytical column using 0.1% formic acid containing 10 mm ammonium formate in distilled water (A) and methanol (B) as mobile phases. All the matrix‐matched calibration curves were linear (R2 ≥ 0.99) over the concentration range of the tested analytes. Recovery at three spiking levels (0.005, 0.01 and 0.02 mg/kg) ranged from 68 to 117% with intra‐ and inter‐day precisions <10%. Five market samples for each matrix (eel, flatfish and shrimp) were collected and tested for method application. In summary, the proposed method is feasible to screen and quantify the analytes with high selectivity in aquatic food products meant for human consumption. 相似文献
999.
Jeong‐Min Choi Weijia Zheng A. M. Abd El‐Aty Seong‐Kwan Kim Da‐Hee Park Kyung‐Hee Yoo Gyu‐Hee Lee Denis A. Baranenko Ahmet Hacmüftüolu Ji Hoon Jeong Young‐Sun Kang Ho‐Chul Shin 《Biomedical chromatography : BMC》2019,33(7)
We developed an analytical method using liquid–liquid extraction (LLE) and liquid chromatography–tandem mass spectrometry (LC‐MS/MS) to detect and quantify tebufenozide (TEB) and indoxacarb (IND) residues in animal and aquatic products (chicken muscle, milk, egg, eel, flatfish, and shrimp). The target compounds were extracted using 1% acetic acid (0.1% acetic acid for egg only) in acetonitrile and purified using n‐hexane. The analytes were separated on a Gemini‐NX C18 column using (a) distilled water with 0.1% formic acid and 5 mm ammonium acetate and (b) methanol with 0.1% formic acid as the mobile phase. All six‐point matrix‐matched calibration curves showed good linearity with coefficients of determination (R2) ≥0.9864 over a concentration range of 5–50 μg/kg. Intra‐ and inter‐day accuracy was expressed as the recovery rate at three spiking levels and ranged between 73.22 and 114.93% in all matrices, with a relative standard deviation (RSD, corresponding to precision) ≤13.87%. The limits of quantification (LOQ) of all target analytes ranged from 2 to 20 μg/kg, which were substantially lower than the maximum residue limits (MRLs) specified by the regulatory agencies of different countries. All samples were collected from different markets in Seoul, Republic of Korea, and tested negative for tebufenozide and indoxacarb residues. These results show that the method developed is robust and may be a promising tool to detect trace levels of the target analytes in animal products. 相似文献
1000.
Jeong Moon Jihyun Byun Hongki Kim Jinyoung Jeong Eun‐Kyung Lim Juyeon Jung Soojeong Cho Woo Kyung Cho Taejoon Kang 《Macromolecular bioscience》2019,19(6)
For the construction of high‐performance biosensor, it is important to interface bioreceptors with the sensor surface densely and in the optimal orientation. Herein, a simple surface modification method that can optimally immobilize antibodies onto various kinds of surfaces is reported. For the surface modification, a mixture of polydopamine (PDA) and protein G was employed. PDA is a representative mussel‐inspired polymer, and protein G is an immunoglobulin‐binding protein that enables an antibody to have an optimal orientation. The surface characteristics of PDA/Protein G mixture‐coated substrates are analyzed and the PDA/protein G ratio is optimized to maximize the antibody binding efficiency. Moreover, the antibody‐immobilized substrates are applied to the detection of influenza viruses with the naked eye, providing a detection limit of 2.9 × 103 pfu mL‐1. Importantly, the several substrates (glass, SiO2, Si, Al2O3, polyethylene terephthalate, polyethylene, polypropylene, and paper) can be modified by simple incubation with the mixture of PDA/protein G, and then the anti‐influenza A H1N1 antibodies can be immobilized on the substrates successfully. Regardless of the substrate, the influenza viruses are detectable after the sandwich immunoreaction and silver enhancement procedure. It is anticipated that the developed PDA/protein G coating method will extend the range of applicable materials for biosensing. 相似文献