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排序方式: 共有293条查询结果,搜索用时 15 毫秒
281.
Franco Salmistraro Roberto Catenacci Annalisa Marzuoli 《General Relativity and Gravitation》1981,13(5):425-432
We consider the Killing-Yano equation by dropping the antisymmetry hypothesis and studying some consequences of the integrability conditions. We find that the cases of interest are more general, and we discuss the relevance of solutions to the construction of Killing tensors. 相似文献
282.
283.
Grimaldi A Banfi S Vizioli J Tettamanti G Noonan DM de Eguileor M 《Macromolecular bioscience》2011,11(8):1008-1019
The biopolymer matrigel loaded with cytokine can be used for the recruitment in vivo of specific cell populations and as a vector for the preparation of cell cultures. Data demonstrate that the injection of the matrigel biopolymer supplemented with interleukin-8 (IL-8) in the leech Hirudo medicinalis can be used to purify cell populations showing the same morphofunctional and molecular mechanisms of specific populations of vertebrate hematopoietic precursor cells involved in tissue repair. These cells spontaneously differentiated into myofibroblasts. This approach highlights how the innovative use of a cytokine-loaded biopolymer for an in vivo cell sorting method, applied to a simple invertebrate model, can be a tool for studying myofibroblast cell biology and its regulation, step by step. 相似文献
284.
Luisa Pasti Elena Sarti Alberto Cavazzini Nicola Marchetti Francesco Dondi Annalisa Martucci 《Journal of separation science》2013,36(9-10):1604-1611
The adsorption behaviour of three commonly used drugs, namely ketoprofen, hydrochlorothiazide and atenolol, from diluted aqueous solutions on beta zeolites with different SiO2/Al2O3 ratio (i.e. 25, 38 and 360) was investigated by changing the ionic strength and the pH, before and after thermal treatment of the adsorbents. The selective adsorption of drugs was confirmed by thermogravimetry and X‐ray diffraction. The adsorption capacity of beta zeolites was strongly dependent on both the solution pH and the alumina content of the adsorbent. Such a remarkable difference was interpreted as a function of the interactions between drug molecules and zeolite surface functional groups. Atenolol was readily adsorbed on the less hydrophobic zeolite, under pH conditions in which electrostatic interactions were predominant. On the other hand, ketoprofen adsorption was mainly driven by hydrophobic interactions. For undissociated molecules the adsorption capability increased with the increase of hydrophobicity. 相似文献
285.
Annalisa La Gatta Chiara Schiraldi Agata PapaMario De Rosa 《Polymer Degradation and Stability》2011,96(4):630-636
The cosmetic market for hyaluronic acid (HA)-based dermal fillers is in continuous and rapid growth and, simultaneously, the development of more effective and safer products is strongly intensifying. In order to highlight the differences among the currently available fillers, in terms of their physical characteristics and on the relation of such properties with product effectiveness, an in vitro evaluation of eight marketed HA-based gels was performed.Filler swelling properties, soluble HA fraction and rheological behaviour were investigated. Furthermore the relative stability to enzymatic hydrolysis was tested. The presence of soluble HA in the formulations varied from 7 ± 1(%) to 33 ± 5(%) with respect to the total HA concentration. Chromatographic analyses showed that the soluble fractions consist of low molecular weight chains (Mw: 260-480 kDa) presenting large distributions (Mw/Mn: 1.6-2.5). The investigated fillers were found to be non-equilibrium gels in their commercial formulation also showing different swelling capacities. Rheological measurements indicated a shear thinning behaviour for all the products and elastic modulus values varied over a wide range (100-1800 Pa). Fillers proved differently sensitive to enzymatic degradation. Swelling capacity and enzymatic stability were found consistently dependent on the total HA concentration, insoluble/soluble HA ratio and on the crosslinking extent. 相似文献
286.
Total Reflection X-ray Fluorescence (TXRF) is a well-established technique for chemical analysis, but it is mainly employed for quality control in the electronics semiconductor industry. The capability to analyze liquid and uniformly thin solid samples makes this technique suitable for other applications, and especially in the very critical field of environmental analysis. Comparison with standard methods like inductively coupled plasma (ICP) and atomic absorption spectroscopy (AAS) shows that TXRF is a practical, accurate, and reliable technique in occupational settings. Due to the greater sensitivity necessary in trace heavy metal detection, TXRF is also suitable for environmental chemical analysis. In this paper we show that based on appropriate standards, TXRF can be considered for non-destructive routine quantitative analysis of environmental matrices such as air filters. This work has been developed in the frame of the EU-FP6 PHIME (Public Health Impact of long-term, low-level Mixed element Exposure in susceptible population strata) Integrated Project (www.phime.org). The aim of this work was to investigate Mn air pollution in the area of Vallecamonica (Italy). 相似文献
287.
An atmospheric pressure plasma enhanced atomic layer deposition reactor has been developed, to deposit Al2O3 films from trimethyl aluminum and an He/O2 plasma. This technique can be used for 2D patterned deposition in a single in‐line process by making use of switched localized plasma sources. It was observed that the sharpness of the patterns is primarily influenced by the concentration of reactive plasma species and by the dimensions of the plasma source. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
288.
Annalisa Chiavaroli Marwa Balaha Alessandra Acquaviva Claudio Ferrante Amelia Cataldi Luigi Menghini Monica Rapino Giustino Orlando Luigi Brunetti Sheila Leone Lucia Recinella Viviana di Giacomo 《Molecules (Basel, Switzerland)》2021,26(20)
Vitis vinifera (grape) contains various compounds with acknowledged phytochemical and pharmacological properties. Among the different parts of the plant, pomace is of particular interest as a winemaking industry by-product. A characterization of the water extract from grape pomace from Montepulciano d’Abruzzo variety (Villamagna doc) was conducted, and the bioactive phenolic compounds were quantified through HPLC-DAD-MS analysis. HypoE22, a hypothalamic cell line, was challenged with an oxidative stimulus and exposed to different concentrations (1 µg/mL−1 mg/mL) of the pomace extract for 24, 48, and 72 h. In the same conditions, cells were exposed to the sole catechin, in a concentration range (5–500 ng/mL) consistent with the catechin level in the extract. Cell proliferation was investigated by MTT assay, dopamine release through HPLC-EC method, PGE2 amount by an ELISA kit, and expressions of neurotrophin brain-derived neurotrophic factor (BDNF) and of cyclooxygenase-2 (COX-2) by RT-PCR. The extract reverted the cytotoxicity exerted by the oxidative stimulus at all the experimental times in a dose-dependent manner, whereas the catechin was able to revert the oxidative stress-induced depletion of dopamine 48 h and 72 h after the stimulus. The extract and the catechin were also effective in preventing the downregulation of BDNF and the concomitant upregulation of COX-2 gene expression. In accordance, PGE2 release was augmented by the oxidative stress conditions and reverted by the administration of the water extract from grace pomace and catechin, which were equally effective. These results suggest that the neuroprotection induced by the extract could be ascribed, albeit partially, to its catechin content. 相似文献
289.
Let G be the direct sum of the noncyclic groupof order four and a cyclic groupwhoseorderisthe power pn of some prime p. We show that ℤ2 G‐lattices have a decidable theory when the cyclotomic polynomia (x) is irreducible modulo 2ℤ for every j ≤ n. More generally we discuss the decision problem for ℤ2 G‐lattices when G is a finite group whose Sylow 2‐subgroups are isomorphic to the noncyclic group of order four. 相似文献
290.