全文获取类型
收费全文 | 2105篇 |
免费 | 90篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 39篇 |
综合类 | 3篇 |
化学工业 | 465篇 |
金属工艺 | 42篇 |
机械仪表 | 59篇 |
建筑科学 | 50篇 |
矿业工程 | 2篇 |
能源动力 | 156篇 |
轻工业 | 144篇 |
水利工程 | 30篇 |
石油天然气 | 10篇 |
无线电 | 238篇 |
一般工业技术 | 519篇 |
冶金工业 | 137篇 |
原子能技术 | 25篇 |
自动化技术 | 283篇 |
出版年
2023年 | 32篇 |
2022年 | 68篇 |
2021年 | 85篇 |
2020年 | 68篇 |
2019年 | 68篇 |
2018年 | 100篇 |
2017年 | 103篇 |
2016年 | 108篇 |
2015年 | 58篇 |
2014年 | 77篇 |
2013年 | 173篇 |
2012年 | 102篇 |
2011年 | 122篇 |
2010年 | 111篇 |
2009年 | 109篇 |
2008年 | 80篇 |
2007年 | 72篇 |
2006年 | 49篇 |
2005年 | 37篇 |
2004年 | 27篇 |
2003年 | 39篇 |
2002年 | 37篇 |
2001年 | 25篇 |
2000年 | 18篇 |
1999年 | 21篇 |
1998年 | 20篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1992年 | 18篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 14篇 |
1988年 | 22篇 |
1987年 | 19篇 |
1986年 | 13篇 |
1985年 | 17篇 |
1984年 | 17篇 |
1983年 | 22篇 |
1982年 | 16篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 11篇 |
1978年 | 13篇 |
1977年 | 9篇 |
1976年 | 12篇 |
1975年 | 13篇 |
1974年 | 9篇 |
排序方式: 共有2202条查询结果,搜索用时 13 毫秒
51.
Santosh Haunshi Rantu Basumatary P.S. Girish Sunil Doley R.K. Bardoloi Ashok Kumar 《Meat science》2009
In the present study, PCR based method for meat species identification of chicken, duck, pigeon and pig was achieved by developing species-specific markers. Using mitochondrial sequences species-specific primers were designed and the sizes of them were 256 bp, 292 bp, 401 bp and 835 bp for chicken, duck, pigeon and pig, respectively. The species-specific PCR products were sequenced to confirm the specificity of the product amplified. These markers were subsequently tested for cross amplification by checking them with beef, mutton, chevon, pork, rabbit, chicken, duck, turkey and pigeon meat. DNA markers developed in this study can help identify the species of fresh, cooked and autoclaved meat of chicken, duck and pigeon and fresh and cooked meat of pig. The process of identification is simple, economical and quick as compared to other methods such as RAPD, PCR-RFLP and sequencing method of species identification. 相似文献
52.
The ultimate tensile strain of anodic films formed on 2024-T4 aluminum was evaluated as a function of pH in environments of 10−3M and 1·0M KNO3, using resistive and capactive techniques. In the resistive technique, ultimate tensile strain was defined as the strain at which a discontinuous increase in anodic current was observed; in the capacitive technique, film failure was marked by a discontinuity in the slope of the capacitance versus strain curve. The ultimate tensile strain was seen to be significantly greater at the zero-point-of charge of the oxide (pH 8) than at higher or lower pH; in the capacitive measurements the ultimate tensile strain had an average value of 0·97 at pH 8 and 0·87 for measurements made at pH values of 4, 7 and 9. Dielectric behavior of the anodic films was seen to be different only in degree from that of films formed on pure aluminum. Changes in capacitance associated only with exposure were measured and taken into account. Capacitance behavior with strain was modeled by two linear regions; the first was attributed to elastic deformation of the film and the second, after failure, to the growth of regions of metal covered only with a thin, spontaneously-formed oxide. 相似文献
53.
Nandita Dasgupta Shivendu Ranjan Shraddha Mundra Ashutosh Kumar 《International Journal of Food Properties》2016,19(3):700-708
The present study was carried out to fabricate the food grade vitamin E acetate nanoemulsion using edible mustard oil and to evaluate its improved bioactivities. A food-grade vitamin E acetate nanoemulsion was fabricated using the edible mustard oil and surfactant Tween-80. Flocculation was not observed for 15 days. The nanoemulsion was characterized for droplet morphology and size distribution using atomic force microscope and zetasizer, respectively. We observe a stable nanoemulsion of spherical morphology and a size distribution of 86.45 ± 3.61 nm. Further, the high-performance liquid chromatography method was used to determine the vitamin E acetate concentration and encapsulation efficiency for the stable nanoemulsion. These nanoemulsions showed improved bioactivity, antioxidant, and antimicrobial activity and could be potentially used to increase the shelf life of fruit juice. 相似文献
54.
Debapriya Mohanty Rajashree Jena Ritesh Pattnaik Swati Mohapatra Manish Ranjan Saini 《International Journal of Food Properties》2016,19(4):837-846
In recent decades, bioactive peptides have attracted increasing interest as health promoting functional foods. A variety of naturally formed bioactive peptides have been found in fermented dairy products such as yogurt, sour milk, and cheese. Initially these peptides are inactive within the sequence of the parent protein molecule and can be generated by gastrointestinal digestion of milk, fermentation of milk with proteolytic starter cultures, and/or hydrolysis by proteolytic enzymes. Milk derived peptides exert a number of health beneficial activities, even upon oral administration. Bioactive peptides have a great impact on major body systems including the digestive, nervous, endocrine, cardiovascular, diabetes type II, obesity, and immune systems. Antimicrobial peptides are also an important ingredient of innate immunity, especially at mucosal surfaces such as lungs and small intestine that are constantly exposed to a range of potential pathogens. Therefore, it plays an important role in boosting natural immune protection by reducing the risk of chronic diseases. Bioactive peptides are considered as potent drugs with well-defined pharmacological residues and also used to formulate health-enhancing nutraceuticals. 相似文献
55.
56.
In this paper, the relationship between the number of unit-cells used in the design of a frequency selective surface (FSS) and its expected directivity is established. The relationship between the number of FSS unit-cells and the directivity is based on the planer microstrip patch array antenna design concept where the unit-cell is treated as the superstrate illuminated by the source. To validate the proposed technique, the analytical value of the directivity has been compared with that of ray-tracing method. The directivity of antenna is calculated for two different planar array configurations at 600 GHz. The results of numerical analysis are compared to that of the full-wave electromagnetic simulator CST Microwave Studio and results are comparable. Further, the directivity computed by this proposed technique has also been compared with that of the reported in literatures. 相似文献
57.
Bansi L Raina Shri G Agarwal Ashok K Bhatia Govind S Gaur 《Journal of the science of food and agriculture》1996,71(1):27-32
Significant variations were observed in the concentration of pigments (10·0–17·0%, moisture-free basis) and flavour components during different post-harvest processing conditions of saffron (stigmas ex Crocus sativus L). The crocin pigments concentration was highest (15–17%) in the saffron samples dried between 35°C and 50°C either in a solar dryer or in an oven dryer and this also resulted in considerable reduction of normal drying time. Under these conditions the main flavouring component, safranal, was at its peak value of 60% in the oil in almost all the samples except the vacuum oven dried samples which interestingly contained 4-β-hydroxysafranal in major amounts. Studies indicated that 4-β-hydroxysafranal may be an intermediate in the formation of safranal. It was observed that prolonged storage affected the pigments and flavour concentration to a great extent, but proper packaging and storage with 5% moisture in the saffron reduced the deterioration, thereby increasing the shelflife of the product. 相似文献
58.
Garrett Jones Tae Jin Lee Joshua Glass Grace Rountree Lane Ulrich Amy Estes Mary Sezer Wenbo Zhi Shruti Sharma Ashok Sharma 《International journal of molecular sciences》2022,23(4)
The tear film is a multi-layer fluid that covers the corneal and conjunctival epithelia of the eye and provides lubrication, nutrients, and protection from the outside environment. Tear fluid contains a high concentration of proteins and has thus been recognized as a potential source of biomarkers for ocular disorders due to its proximity to disease sites on the ocular surface and the non-invasive nature of its collection. This is particularly true in the case of dry eye disease, which directly impacts the tear film and its components. Proteomic analysis of tear fluid is challenging mainly due to the wide dynamic range of proteins and the small sample volumes. However, recent advancements in mass spectrometry have revolutionized the field of proteomics enabling unprecedented depth, speed, and accuracy, even with small sample volumes. In this study using the Orbitrap Fusion Tribrid mass spectrometer, we compared four different mass spectrometry workflows for the proteomic analysis of tear fluid collected via Schirmer strips. We were able to establish a method of in-strip protein digestion that identified >3000 proteins in human tear samples from 11 healthy subjects. Our method offers a significant improvement in the number of proteins identified compared to previously reported methods without pooling samples. 相似文献
59.
Maurya Ranjan Kumar Kaur Rajvinder Kumar Ramesh Agarwal Ajay 《Microsystem Technologies》2019,25(10):3933-3941
Microsystem Technologies - This paper reports the development of a novel electronic micro-viscometer capable of measuring viscosity of different Newtonian fluids using less than 100 µl which... 相似文献
60.
Neural Computing and Applications - Heart diseases are of notable public health disquiet worldwide. Heart patients are growing speedily owing to deficient health awareness and bad consumption... 相似文献