全文获取类型
收费全文 | 744篇 |
免费 | 69篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 16篇 |
综合类 | 2篇 |
化学工业 | 220篇 |
金属工艺 | 13篇 |
机械仪表 | 16篇 |
建筑科学 | 30篇 |
能源动力 | 23篇 |
轻工业 | 122篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 51篇 |
一般工业技术 | 101篇 |
冶金工业 | 40篇 |
原子能技术 | 6篇 |
自动化技术 | 170篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 20篇 |
2021年 | 46篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 42篇 |
2017年 | 37篇 |
2016年 | 45篇 |
2015年 | 32篇 |
2014年 | 47篇 |
2013年 | 58篇 |
2012年 | 42篇 |
2011年 | 59篇 |
2010年 | 40篇 |
2009年 | 46篇 |
2008年 | 24篇 |
2007年 | 29篇 |
2006年 | 26篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 8篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 9篇 |
1999年 | 12篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有814条查询结果,搜索用时 31 毫秒
41.
N‐Benzyl‐4‐((heteroaryl)methyl)benzamides: A New Class of Direct NADH‐Dependent 2‐trans Enoyl–Acyl Carrier Protein Reductase (InhA) Inhibitors with Antitubercular Activity 下载免费PDF全文
Ana Guardia Dr. Gulcin Gulten Dr. Raquel Fernandez Jesus Gómez Dr. Feng Wang Dr. Maire Convery Delia Blanco María Martínez Dr. Esther Pérez‐Herrán Marta Alonso Dr. Fátima Ortega Dr. Joaquín Rullás Dr. David Calvo Lydia Mata Dr. Robert Young Prof. James C. Sacchettini Dr. Alfonso Mendoza‐Losana Dr. Modesto Remuiñán Dr. Lluís Ballell Pages Dr. Julia Castro‐Pichel 《ChemMedChem》2016,11(7):687-701
Isoniazid (INH) remains one of the cornerstones of antitubercular chemotherapy for drug‐sensitive strains of M. tuberculosis bacteria. However, the increasing prevalence of multidrug‐resistant (MDR) and extensively drug‐resistant (XDR) strains containing mutations in the KatG enzyme, which is responsible for the activation of INH into its antitubercular form, have rendered this drug of little or no use in many cases of drug‐resistant tuberculosis. Presented herein is a novel family of antitubercular direct NADH‐dependent 2‐trans enoyl–acyl carrier protein reductase (InhA) inhibitors based on an N‐benzyl‐4‐((heteroaryl)methyl)benzamide template; unlike INH, these do not require prior activation by KatG. Given their direct InhA target engagement, these compounds should be able to circumvent KatG‐related resistance in the clinic. The lead molecules were shown to be potent inhibitors of InhA and showed activity against M. tuberculosis bacteria. This new family of inhibitors was found to be chemically tractable, as exemplified by the facile synthesis of analogues and the establishment of structure–activity relationships. Furthermore, a co‐crystal structure of the initial hit with the enzyme is disclosed, providing valuable information toward the design of new InhA inhibitors for the treatment of MDR/XDR tuberculosis. 相似文献
42.
Christoph Schmerbauch Jesus Gonzalez‐Julian Robert Röder Carsten Ronning Olivier Guillon 《Journal of the American Ceramic Society》2014,97(6):1728-1735
We report the sintering behavior of nanocrystalline zinc oxide under external AC electric field between 0 and 160 V/cm. In situ acquisition of density by means of laser dilatometry, evaluation of specimen temperature, real‐time measurement of electric field and current help analyze this peculiar behavior. Field strength and blocking electrodes significantly affect densification and microstructure, which was evaluated in the vicinity of the flash event and for the fully sintered material. High current densities flow through the sample at high electric fields, entailing a sudden increment of the temperature estimated to several hundreds of K and an exaggerated grain growth. In contrast, low current density flows through the sample at lower electric fields, which guarantees normal grain growth and highest final density. Macroscopic photoluminescence measurements give insights into the development of the defect structure. Electric fields are expected to enhance defect mobility, explaining the high densification rates observed during the sintering process. 相似文献
43.
Jesus Palomino Oviedo Robert Metz John Schulz Ralf‐Peter Tressel Frank Pudel 《化学,工程师,技术》2014,86(8):1249-1259
Protein samples of rapeseed were prepared with different compositions as protein isolate, protein concentrate and acetylated protein concentrate. They showed functional properties which are consolidated in the coating. The manufactured protein samples were tested in a pilot‐scale paperboard coating plant. The results indicated that the use of rapeseed proteins in the coating preparation is technically feasible and that the color and roughness of the coated paperboard show no negative effect on the quality. Industry printing experiments with this coated paperboard achieved the standard quality. 相似文献
44.
Maria D Guilln Nerea Cabo and Jesus Burillo 《Journal of the science of food and agriculture》1996,70(3):359-363
The compositions of the essential oils of Rosmarinus officinalis L, Salvia lavandulifolia V and Lavandula latifolia M, obtained by steam distillation from plants cultivated in the northeast of Spain, have been studied by gas chromatography and gas chromatography/mass spectrometry. The essential oil of rosemary appears to be more complex and richer in flavour notes than other previously studied Spanish rosemary oils, and has an intermediate ratio of α-pinene and of 1,8-cineole in relation to essential oils of rosemary of different geographical origins, but higher proportions of camphor, verbenone and linalool. The essential oil of sage has proportions of 1,8-cineole, camphor, endo-borneol, trans-caryophyllene and α-humulene closer to commercial Salvia officinalis L than to other Spanish sages of different geographical locations, and the difference from commercial Salvia officinalis L is due principally to the higher ratio of terpene hydrocarbons and the lower proportion of thujone in the Spanish sage studied here. The essential oil of the spike lavender has the same main components and similar proportions as other Spanish wild and commercial spike lavender essen-tial oils, but shows differences in the nature of the minor components (rhodinol fraction). 相似文献
45.
Xiaobo Dong Halle D. Shannon Caleb Parker Samantha De Jesus Isabel C. Escobar 《American Institute of Chemical Engineers》2020,66(1):e16790
Petroleum-derived solvents commonly used in membrane fabrication are often hazardous and toxic, so the investigation of safer alternatives is important. In this study, two low-hazard solvents, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® PolarClean) and gamma-valerolactone (GVL), were investigated as sole solvents and as cosolvents to cast polysulfone membranes via nonsolvent induced phase inversion. Normalized viscosity was introduced as an indicator of dope solution homogeneity and was used to compare the required time of mixing to achieve full dissolution of the polymer in the different solvents/solvent mixtures. All dope solutions made with low-hazard solvents were found to be more viscous than those made with traditional solvents, which meant additional mixing time was needed, and that fabricated membranes were morphologically different. With respect to operation, membranes cast from dope solutions containing equal amounts of PolarClean and GVL displayed the most similar flux curves and solute rejection to those made using the traditional solvent tested. 相似文献
46.
47.
Crespo JF Retzek M Foetisch K Sierra-Maestro E Cid-Sanchez AB Pascual CY Conti A Feliu A Rodriguez J Vieths S Scheurer S 《Molecular nutrition & food research》2006,50(3):282-290
Oranges are clinically relevant allergenic foods. To date, orange allergens have not been characterized in detail. The study is aimed at analyzing the sensitization profile in orange-sensitized subjects with and without clinical allergy, and to identify orange allergens. Fifty-six sensitized subjects with self-reported reactions to orange were grouped into reactors (anaphylaxis or multiple episodes of immediate reactions and/or positive challenge tests) and non-reactors (negative open food challenge tests). Allergens were characterized by IgE immunoblotting, N-terminal sequencing, IgE-inhibition assays, and mediator release assays were performed to determine the allergenic potency of orange profilin. Of 56 subjects, 23 were classified as orange allergic showing mainly an oral allergy syndrome. Of 23 subjects classified as orange allergic, 22 were sensitized to profilin, Cit s 2. In patients with mono-sensitization to profilin in vitro histamine releases up to 75% from basophils were induced using orange extract and purified plant profilins. Of the allergic patients 78% were sensitized to germin-like protein, Cit s 1. Both allergens showed retained IgE reactivity in heat-processed orange juice. Interestingly, subjects with and without clinical allergy showed a comparable sensitization profile. Profilin and germin-like proteins are major orange allergens. The potential clinical relevance of orange profilin was indicated by its strong capacity to release histamine from basophils. However, a predominant sensitization to both allergens in subjects without symptoms also indicates a high frequency of clinically insignificant sensitization. 相似文献
48.
Cuauhtémoc Flores Ferreyra Angel de Jesus Morales Ramirez Hugo Martinez Gutierrez 《腐蚀工程科学与技术》2017,52(3):236-243
This study compares the hot corrosion performance of yttria-stabilised zirconia (7YSZ), and 7YSZ?+?Gd2O3 composite samples in the presence of molten mixture of Na2SO4?+?V2O5 at 1150°C. For 7YSZ, the reaction between NaVO3 and Y2O3 produces YVO4 and leads the transformation of tetragonal ZrO2 to monoclinic ZrO2. A high-density in sintered 7YSZ?+?Gd2O3 samples, led minor amounts of monoclinic ZrO2 and tetragonal GdVO4 as the hot corrosion products with only traceable amounts of YVO4, and a stable corroded layer was formed. Due to the synergic effect of doping of zirconia with Gd2O3, the 7YSZ?+?Gd2O3 sample has a much better hot corrosion crack resistance than 7YSZ. 相似文献
49.
Clemente Neves Sousa Paulo Teles Vanessa Filipa Ferreira Dias João Luís Alves Apóstolo Maria Henriqueta Jesus Silva Figueiredo Maria Manuela Martins 《Hemodialysis international. International Symposium on Home Hemodialysis》2014,18(3):695-699
Vascular access is one of the leading causes of mobilization of financial resources in health systems for people with chronic kidney disease on hemodialysis. Physical examination of the arteriovenous fistula (AVF) has demonstrated its effectiveness in identifying complications. We decided to evaluate the influence of nurses' professional experience in the detection of complications of the AVF (venous stenosis and steal syndrome). The study took place in eight hemodialysis centers between May and September of 2011 in the north of Portugal. Sample was constituted by registered nurses. The nurses involved in the experiment were divided in two groups: those who had more than 5 years of experience and those who had less than 5 years of experience. Ninety‐two nurses participated in the study: 34 nurses had less than 5 years of professional experience and 58 had more than 5 years of professional experience. In the practices considered by nurses in the detection of venous stenosis, there were no differences observed between the groups (P > 0.05). In steal syndrome, there were no differences observed between the groups in the practices of the nurses in the detection of this complication of the AVF (P > 0.05). We concluded that professional experience does not influence the detection of venous stenosis and steal syndrome. 相似文献