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421.
The synthesis of NiO/NiCo2O4 nanoparticles by an eco-friendly, fast, simple and cost-effective approach employing Urtica extract is reported in this study. The NiO/NiCo2O4 nanocomposite were characterized using VSM, FTIR, XRD, and SEM techniques. Moreover, to construct a modified carbon paste electrode, NiO/NiCo2O4 were employed and this sensor was used for dopamine (DA) detection. Using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques, the electrochemical behavior of dopamine at the NiO/NiCo2O4/CPE was investigated. Analysis of dopamine, with a limit of detection (LOD) equal to 0.04 μM, in the concentration range of 0.1–100.0 μM, was facilitated by NiO/NiCo2O4/CPE. Moreover, the satisfactory selectivity for DA determination in the presence of uric acid (UA) and ascorbic acid (AA), was obtained. The suggested new sensor displayed a good reproducibility, sensitivity, and stability for determination of DA in drug and biological samples. 相似文献
422.
Marjani Ahmad Poursattar Hosseini Seyed Ali Shokri Zahra Maleki Nasim 《Research on Chemical Intermediates》2017,43(1):413-422
Research on Chemical Intermediates - N-formylation of different amines was carried out with formic acid in the presence of the Co3O4 nanoparticles as an efficient, stable heterogeneous catalyst to... 相似文献
423.
Microchimica Acta - Carbon nanospheres were covalently modified with hydroxy-terminated poly(dimethylsiloxane) to give a new sorbent (referred to as CNS-PDMS). It was applied as the extraction... 相似文献
424.
Paenilamicin: Structure and Biosynthesis of a Hybrid Nonribosomal Peptide/Polyketide Antibiotic from the Bee Pathogen Paenibacillus larvae 下载免费PDF全文
Sebastian Müller Dr. Eva Garcia‐Gonzalez Dr. Andi Mainz Gillian Hertlein Nina C. Heid Eva Mösker Hans van den Elst Prof. Dr. Herman S. Overkleeft Priv.‐Doz. Dr. Elke Genersch Prof.Dr. Roderich D. Süssmuth 《Angewandte Chemie (International ed. in English)》2014,53(40):10821-10825
The spore‐forming bacterium Paenibacillus larvae is the causative agent of American Foulbrood (AFB), a fatal disease of honey bees that occurs worldwide. Previously, we identified a complex hybrid nonribosomal peptide/polyketide synthesis (NRPS/PKS) gene cluster in the genome of P. larvae. Herein, we present the isolation and structure elucidation of the antibacterial and antifungal products of this gene cluster, termed paenilamicins. The unique structures of the paenilamicins give deep insight into the underlying complex hybrid NRPS/PKS biosynthetic machinery. Bee larval co‐infection assays reveal that the paenilamicins are employed by P. larvae in fighting ecological niche competitors and are not directly involved in killing the bee larvae. Their antibacterial and antifungal activities qualify the paenilamicins as attractive candidates for drug development. 相似文献
425.
Spectroscopic,Thermal, and Structural Studies of Two New Co‐Crystals of [4,4′‐Bithiazole]‐2,2′‐diamine 下载免费PDF全文
Zohreh Rashidi Ranjbar Ali Morsali Maryam Ghoreishi Amiri 《Helvetica chimica acta》2014,97(5):701-707
Two new 2 : 1 co‐crystals based on [4,4′‐bithiazole]‐2,2′‐diamine (=2,2′‐diamino‐4,4′‐bithiazole (DABTZ)) with 2,2′‐bipyridine (bipy) and benzo‐18‐crown‐6 (bk) were synthesized by slow‐evaporation method in MeOH. These co‐crystals were characterized by means of elemental analysis, and IR, and 1H‐ and 13C‐NMR spectroscopy. Also, thermal analyses under air atmosphere and X‐ray crystallography have been performed on these structures. X‐Ray single‐crystal analyses revealed that these networks contain large vacant voids. These structures, [(DABTZ)2(bipy)] and [(DABTZ)2(bk)(MeOH)], crystallized in monoclinic and triclinic forms with space groups of P21/c and P , respectively. The self‐assembly of these compounds in the solid state is likely caused by both H‐bonding and π? π stacking. 相似文献
426.
Mehdi Shanbedi Ahmad Amiri Majid Baniadam 《Journal of Dispersion Science and Technology》2014,35(8):1086-1096
Hereby, a comparative study of thermal and thermodynamic properties of nanofluids based on multiwalled carbon nanotubes (MWCNTs) and water is described. The first nanofluid includes pristine MWCNT while the second nanofluid prepared by MWCNT decorated with silver. To achieve the covalent functionalization, morphology of MWCNT-Ag was studied by transmission electron microscopy. Subsequently, the value of the entropy generation and thermal performance of nanofluids (MWCNT/water and MWCNT-Ag/water) were inspected in a two-phased closed thermosyphon (TPCT). The results suggested as the concentration and input power increased, the thermal resistance decreased. Also in different concentrations, the thermal efficiency of nanofluids obeyed the sequence: MWCNT-Ag (1 wt%) > MWCNT-Ag (0.5 wt%) > MWCNT (1 wt%) > MWCNT (0.5 wt%) > water. A variation of the vacuum pressure was also studied in the synthesized nanofluids as compared with pure water. The results were shown a lower pressure drop of MWCNT-Ag/water than MWCNT/water and the water. Also it was found that the higher thermal performance is produced using higher extent of covalent functional groups (with higher thermal conductivity). MWCNT-Ag/water can be an appropriate substitution for the water in the thermal equipment due to the intensive thermal efficiency and/or low thermal resistance compared with pure water. 相似文献
427.
Regression models provide prediction frameworks for multivariate mutual information analysis that uses information concepts when choosing covariates (also called features) that are important for analysis and prediction. We consider a high dimensional regression framework where the number of covariates (p) exceed the sample size (n). Recent work in high dimensional regression analysis has embraced an ensemble subspace approach that consists of selecting random subsets of covariates with fewer than p covariates, doing statistical analysis on each subset, and then merging the results from the subsets. We examine conditions under which penalty methods such as Lasso perform better when used in the ensemble approach by computing mean squared prediction errors for simulations and a real data example. Linear models with both random and fixed designs are considered. We examine two versions of penalty methods: one where the tuning parameter is selected by cross-validation; and one where the final predictor is a trimmed average of individual predictors corresponding to the members of a set of fixed tuning parameters. We find that the ensemble approach improves on penalty methods for several important real data and model scenarios. The improvement occurs when covariates are strongly associated with the response, when the complexity of the model is high. In such cases, the trimmed average version of ensemble Lasso is often the best predictor. 相似文献
428.
Molecular Diversity - A simple approach for the synthesis of spiroacenaphthylene-pyranopyrazole derivatives was achieved via the reaction between acenaphthoquinone, pyrazolones, and activated... 相似文献
429.
Rafieh-Sadat Norouzian Amiri Nader Taheri Qazvini Naser Sharifi Sanjani 《Journal of Macromolecular Science: Physics》2013,52(5):955-966
A published process for preparing expandable polystyrene containing water as a blowing agent was applied to synthesize water expandable polystyrene-organoclay nanocomposites (WEPS-OCN). Organoclay was uniformly dispersed in styrene monomer. During suspension polymerization, water was trapped in the polystyrene (PS) matrix through the use of starch, ending up with spherical PS-organoclay beads. By selecting organoclays with various surfactants and modifier concentrations, different distribution states of nanoclay in the PS matrix, from cluster (poor dispersion) to either intercalated (limited dispersion) or exfoliated (full dispersion) were obtained. The incorporation of organoclay led to higher water content in the expandable beads. However, as expected, the flammability of the expanded product was increased with organoclay content. Furthermore, the results showed that the average unexpanded bead size, density of preexpanded beads, foam cell morphology, and flammability were directly influenced by the dispersion status of the organoclay. The best results were obtained when full dispersion (exfoliation) of nanoclay in PS matrix occurred. 相似文献
430.
Monajjemi M. Ketabi S. Amiri A. 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(1):S55-S62
The tetramerization of melittin, a 26-amino-acid peptide, is considered as a model for protein folding. The Monte Carlo simulation was used to study the folding arrangement of melittin, and the results are compared with the experiment. An acceptance rate of 50% for new configurations is achieved by using ranges of ±0.001 Å for the translations and ±15°C for the rotations. Around 311 K, the folded structure of the protein has the greatest stability; the range from −40 to −80 shows the best ϕ angles for melittin. The final optimized structure of melittin strongly depends on the temperature. The melittin tetramer is found to have a temperature of maximum stability ranging from 35.5 to 43°C.
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