全文获取类型
收费全文 | 572篇 |
免费 | 65篇 |
国内免费 | 3篇 |
专业分类
化学工业 | 203篇 |
金属工艺 | 6篇 |
机械仪表 | 27篇 |
建筑科学 | 19篇 |
矿业工程 | 3篇 |
能源动力 | 14篇 |
轻工业 | 208篇 |
水利工程 | 4篇 |
石油天然气 | 6篇 |
无线电 | 12篇 |
一般工业技术 | 70篇 |
冶金工业 | 21篇 |
自动化技术 | 47篇 |
出版年
2024年 | 3篇 |
2023年 | 13篇 |
2022年 | 46篇 |
2021年 | 53篇 |
2020年 | 27篇 |
2019年 | 42篇 |
2018年 | 35篇 |
2017年 | 25篇 |
2016年 | 29篇 |
2015年 | 33篇 |
2014年 | 32篇 |
2013年 | 58篇 |
2012年 | 32篇 |
2011年 | 53篇 |
2010年 | 29篇 |
2009年 | 30篇 |
2008年 | 15篇 |
2007年 | 22篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1994年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1982年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有640条查询结果,搜索用时 26 毫秒
561.
Analía Alvarez Claudia S. Benimeli Juliana M. Saez María S. Fuentes Sergio A. Cuozzo Marta A. Polti María J. Amoroso 《International journal of molecular sciences》2012,13(11):15086-15106
In the last few decades, highly toxic organic compounds like the organochlorine pesticide (OP) hexachlorocyclohexane (HCH) have been released into the environment. All HCH isomers are acutely toxic to mammals. Although nowadays its use is restricted or completely banned in most countries, it continues posing serious environmental and health concerns. Since HCH toxicity is well known, it is imperative to develop methods to remove it from the environment. Bioremediation technologies, which use microorganisms and/or plants to degrade toxic contaminants, have become the focus of interest. Microorganisms play a significant role in the transformation and degradation of xenobiotic compounds. Many Gram-negative bacteria have been reported to have metabolic abilities to attack HCH. For instance, several Sphingomonas strains have been reported to degrade the pesticide. On the other hand, among Gram-positive microorganisms, actinobacteria have a great potential for biodegradation of organic and inorganic toxic compounds. This review compiles and updates the information available on bacterial removal of HCH, particularly by Streptomyces strains, a prolific genus of actinobacteria. A brief account on the persistence and deleterious effects of these pollutant chemical is also given. 相似文献
562.
Alejandro C. Frery Julio Jacobo-Berlles Juliana Gambini Marta E. Mejail 《Multidimensional Systems and Signal Processing》2010,21(4):319-342
We present an approach for polarimetric Synthetic Aperture Radar (SAR) image region boundary detection based on the use of
B-Spline active contours and a new model for polarimetric SAR data: the GPH{\mathcal{G}_P^H} distribution. In order to detect the boundary of a region, initial B-Spline curves are specified, either automatically or
manually, and the proposed algorithm uses a deformable contours technique to find the boundary. In doing this, the parameters
of the polarimetric GPH{\mathcal{G}_P^H} model for the data are estimated, in order to find the transition points between the region being segmented and the surrounding
area. This is a local algorithm since it works only on the region to be segmented. Results of its performance are presented. 相似文献
563.
Brazilian Ginseng extraction via LPSE and SFE: Global yields, extraction kinetics, chemical composition and antioxidant activity 总被引:1,自引:0,他引:1
Patrícia F. Leal Fábio C. Alexandre Juliana M. Prado M. Angela A. Meireles 《The Journal of Supercritical Fluids》2010,54(1):38-45
Brazilian Ginseng extracts of two species, Pfaffia paniculata and Pfaffia glomerata, were obtained by supercritical fluid extraction (SFE) with CO2 and by low-pressure solvent extraction (LPSE) with methanol, hexane and ethanol. The SFE assays were conducted at pressures of 100, 200 and 300 bar, and temperatures of 30 and 50 °C. The qualitative chemical compositions of the extracts were determined by thin layer chromatography (TLC). One of the active principles of interest from P. glomerata extract, β-ecdysone, was identified and quantified by HPLC. The antioxidant activities of Brazilian Ginseng extracts were determined by the coupled reaction of linolenic acid and β-carotene. For P. paniculata, the highest SFE yield was obtained at 200 bar/50 °C (0.22%, dry basis—d.b.), while the best extraction condition for P. glomerata was obtained at 200 bar/30 °C (0.18%, d.b.). The higher extract yields obtained by LPSE were 2.0% and 5.8% (w/w, d.b.) for P. paniculata and P. glomerata, respectively, both obtained with methanol as extraction solvent. From the overall extraction curve of P. glomerata, it was possible to obtain the kinetic parameters of extraction; the duration of the CER (constant extraction rate) period was determined as 134 min. The TLC plates showed the possible presence of flavonoids in the ethanolic extract for both Pfaffia species. The antioxidant activity analysis detected that LPSE extracts had higher activity than SFE extracts. 相似文献
564.
Miguel Bagajewicz Season Hill Amanda Robben Heyde Lopez Monica Sanders Erin Sposato Curtis Baade Shamara Manora Juliana Hey Coradin 《American Institute of Chemical Engineers》2011,57(1):160-177
In this article, we apply a recently developed method for product design to the formulation of skin lotions and extend its application to consider price‐competitive markets. The method is based on the use of consumer preference functions that are in turn parameters of price‐demand relations. These relationships are then embedded in a business model that aims at determining the optimal lotion formulation from the profitability point of view. The model allows to distinguish the formulation that leads to the consumer most preferred skin lotion from the most profitably one in a quantitative fashion. In the latter case, the selling price is also determined simultaneously with the optimal formulation. The example analyzed shows that the consumer most preferred lotion is not profitable, whereas a slightly less preferred lotion is very profitable. We then extend the new product design procedure to consider a competitive environment in which prices of all competitors, change dynamically until equilibrium is established. © 2010 American Institute of Chemical Engineers AIChE J, 2011 相似文献
565.
Juliana Gamboa‐Santos Ana C. Soria Tiziana Fornari Mar Villamiel Antonia Montilla 《International Journal of Food Science & Technology》2013,48(10):1998-2006
The effect of drying temperature (40–65 °C) and air rate (2–6 m s?1) on the formation of Maillard reaction indicators and vitamins content of carrots dehydrated by convection has been investigated. The range of assayed processing conditions, based on a previous central composite face design (CCD), led to moderate changes in the studied parameters, even under the most severe conditions. In addition, the drying kinetic of the process was studied taking into account the experimental quantitation of shrinkage, which allowed the determination of a first drying period with a constant rate of water evaporation per unit of exchange surface. The slope of the first drying period, the moisture loss during the first hour of drying and the level of quality parameters (Maillard reaction indicators and vitamins) were correlated with processing conditions with high accuracy. For the prototype here used, the optima temperature and air rate to maximise the desirability function (0.77) were 46 °C and 4.9 m s?1. 相似文献
566.
567.
Gene therapy has continuously evolved throughout the years since its first proposal to develop more specific and effective transfection, capable of treating a myriad of health conditions. Viral vectors are some of the most common and most efficient vehicles for gene transfer. However, the safe and effective delivery of gene therapy remains a major obstacle. Ultrasound contrast agents in the form of microbubbles have provided a unique solution to fulfill the need to shield the vectors from the host immune system and the need for site specific targeted therapy. Since the discovery of the biophysical and biological effects of microbubble sonification, multiple developments have been made to enhance its applicability in targeted drug delivery. The concurrent development of viral vectors and recent research on dual vector strategies have shown promising results. This review will explore the mechanisms and recent advancements in the knowledge of ultrasound-mediated microbubbles in targeting gene and drug therapy. 相似文献
568.
569.
Biodegradable starch particles for controlled release applications: Swelling and leaching mechanisms
Starch-extruded particles have only found infrequent use as delivery systems for active ingredients. We have previously shown that these particles are attractive for releasing hydrophobic compounds in water media. Here, we cover a range of amylose–amylopectin ratios and evaluate the presence of the thyme essential oil (TEO) as active compound to understand the dominant release mechanism in relation to the physicochemical properties of the starch matrices. Starch blends with high amylopectin content (1.8 and 15% amylose) could not be shaped into regular particles. For amylose contents higher than 28%, the equilibrium degree of swelling in water decreased with increasing amylose contents, from nearly 300% for an amylose content of 28–90% at an amylose content of 70%. For both lowest amylose contents, 1.8 and 15%, leaching of solids and disintegration of the particles resulted in a low apparent degree of swelling. The presence of TEO reduces the degree of swelling of the gelatinized starch matrix. This is explained by the formation of thymol–amylose complexes, which is confirmed by Fourier transform infrared spectroscopy analysis and X-ray diffraction. 相似文献
570.
Preethi Bala Balakrishnan Debbie K.Ledezma Juliana Cano-Mejia Jadyn Andricovich Erica Palmer Vishal A.Patel Patricia S.Latham Eric S.Yvon Alejandro Villagra Rohan Femandes Elizabeth E.Sweeney 《Nano Research》2022,(3):2300-2314
Despite the promise of immunotherapy such as the immune checkpoint inhibitors(ICIs)anti-PD-1 and anti-CTLA-4 for advanced melanoma,only 26%-52%of patients respo... 相似文献