全文获取类型
收费全文 | 6869篇 |
免费 | 149篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 84篇 |
综合类 | 4篇 |
化学工业 | 1189篇 |
金属工艺 | 99篇 |
机械仪表 | 124篇 |
建筑科学 | 278篇 |
矿业工程 | 27篇 |
能源动力 | 134篇 |
轻工业 | 465篇 |
水利工程 | 52篇 |
石油天然气 | 16篇 |
无线电 | 694篇 |
一般工业技术 | 1053篇 |
冶金工业 | 1946篇 |
原子能技术 | 72篇 |
自动化技术 | 787篇 |
出版年
2022年 | 46篇 |
2021年 | 91篇 |
2020年 | 50篇 |
2019年 | 49篇 |
2018年 | 78篇 |
2017年 | 73篇 |
2016年 | 93篇 |
2015年 | 59篇 |
2014年 | 107篇 |
2013年 | 360篇 |
2012年 | 162篇 |
2011年 | 247篇 |
2010年 | 184篇 |
2009年 | 203篇 |
2008年 | 212篇 |
2007年 | 196篇 |
2006年 | 180篇 |
2005年 | 193篇 |
2004年 | 185篇 |
2003年 | 159篇 |
2002年 | 140篇 |
2001年 | 122篇 |
2000年 | 121篇 |
1999年 | 156篇 |
1998年 | 442篇 |
1997年 | 273篇 |
1996年 | 234篇 |
1995年 | 195篇 |
1994年 | 165篇 |
1993年 | 167篇 |
1992年 | 123篇 |
1991年 | 96篇 |
1990年 | 105篇 |
1989年 | 114篇 |
1988年 | 104篇 |
1987年 | 100篇 |
1986年 | 107篇 |
1985年 | 110篇 |
1984年 | 100篇 |
1983年 | 76篇 |
1982年 | 69篇 |
1981年 | 90篇 |
1980年 | 75篇 |
1979年 | 73篇 |
1978年 | 62篇 |
1977年 | 95篇 |
1976年 | 113篇 |
1975年 | 47篇 |
1974年 | 52篇 |
1973年 | 39篇 |
排序方式: 共有7024条查询结果,搜索用时 31 毫秒
1.
Nitsa Buaron Antonella Mangraviti Francesco Volpin Ann Liu Mariangela Pedone Eric Sankey Dina Aranovich Itay Adar Fausto J. Rodriguez Abraham Nyska Riki Goldbart Tamar Traitel Henry Brem Betty Tyler Joseph Kost 《Advanced functional materials》2021,31(44):2100643
Treating neuroinflammation-related injuries and disorders through manipulation of neuroinflammation functions is being heralded as a new therapeutic strategy. In this study, a novel pectic galactan (PG) polysaccharide based gene therapy approach is developed for targeting reactive gliosis in neuroinflammation. Galectin-3 (Gal-3) is a cell protein with a high affinity to β-galactoside sugars and is highly expressed in reactive gliosis. Since PG carries galactans, it can target reactive gliosis via specific carbohydrate interaction between galactan and Gal-3 on the cell membrane, and therefore can be utilized as a carrier for delivering genes to these cells. The carrier is synthesized by modifying quaternary ammonium groups on the PG. The resulting quaternized PG (QPG) is found to form complexes with plasmid DNA with a mean diameter of 100 nm and have the characteristics required for targeted gene therapy. The complexes efficiently condense large amounts of plasmid per particle and successfully bind to Gal-3. The in vivo study shows that the complexes are biocompatible and safe for administration and can selectively transfect reactive glial cells of an induced cortical lesion. The results confirm that this PG-based delivery system is a promising platform for targeting Gal-3 overexpressing neuroinflammation cells for treating neuroinflammation-related injuries and neurodegenerative diseases. 相似文献
2.
3.
Jokerst N.M. Gaylord T.K. Glytsis E. Brooke M.A. Cho S. Nonaka T. Suzuki T. Geddis D.L. Shin J. Villalaz R. Hall J. Chellapa A. Vrazel M. 《Advanced Packaging, IEEE Transactions on》2004,27(2):376-385
This paper explores design options for planar optical interconnections integrated onto boards, discusses fabrication options for both beam turning and embedded interconnections to optoelectronic devices, describes integration processes for creating embedded planar optical interconnections, and discusses measurement results for a number of integration schemes that have been demonstrated by the authors. In the area of optical interconnections with beams coupled to and from the board, the topics covered include integrated metal-coated polymer mirrors and volume holographic gratings for optical beam turning perpendicular to the board. Optical interconnections that utilize active thin film (approximately 1-5 /spl mu/m thick) optoelectronic components embedded in the board are also discussed, using both Si and high temperature FR-4 substrates. Both direct and evanescent coupling of optical signals into and out of the waveguide are discussed using embedded optical lasers and photodetectors. 相似文献
4.
I. Tsukanov M. Hall 《International journal for numerical methods in engineering》2003,56(13):1949-1972
In this paper we discuss the data structure and algorithms for the direct application of generalized Leibnitz rules to the numerical computation of partial derivatives in forward mode. The proposed data structure provides constant time access to the partial derivatives, which accelerates the automatic differentiation computations. The interaction among elements of the data structure is explained by several numerical examples. The paper contains analysis of the developed data structure and algorithms. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
5.
F Koumanov C Henry C Ghezzi JP Mathieu C Morin M Vidal J de Leiris M Comet D Fagret 《Canadian Metallurgical Quarterly》1997,24(6):519-525
Two anomeric analogues of glucose labelled with 123 iodine in position 6, proposed as tracers of glucose transport in vivo, have been synthesized: alpha- and beta-methyl-6-deoxy-6-iodo-D-glucopyranoside (alpha MDIG and beta MDIG). The aim of this study was to determine whether these molecules interact with the glucose transporter and whether they could be used as tracers of glucose transport in vivo. The biodistribution of alpha MDIG and beta MDIG was studied in the mouse in vivo. To determine if these two anomers enter the cell via the glucose transporter, their uptake was measured in isolated perfused rat hearts, in human erythrocytes in suspension, and in cardiomyocytes of neonatal rat in culture. Both alpha MDIG and beta MDIG had similar repartitions in the mouse: myocardial uptake averaged 7% of the injected dose/g of organ at 2 min postinjection and alpha MDIG competed with D-glucose to enter the cells. Insulin produced a 123% increase of its uptake in isolated perfused rat hearts and a 100% increase in cardiomyocytes of neonatal rat in culture. alpha MDIG uptake was lowered in the presence of glucose transport inhibitors in each experimental model. An interaction between beta MDIG and glucose transporters was observed only in human erythrocytes in suspension. Only alpha MDIG interacts with the glucose transporter, and thus could be used to estimate glucose transport in vivo. 相似文献
6.
7.
8.
9.
Maribel Plascencia‐Jatomea Miguel A Olvera‐Novoa Jos Luis Arredondo‐Figueroa George M Hall Keiko Shirai 《Journal of the science of food and agriculture》2002,82(7):753-759
This study provides information on the use of shrimp head silage protein hydrolysate (SPH) as an alternative protein source for tilapia feeding. Six diets (28% protein, 12% lipid) were prepared where fishmeal protein was replaced at levels of 0 (control), 10, 15, 20, 25 and 30% with the hydrolysate. The diets were supplied to Nile tilapia fry (338 mg initial weight) stocked in plastic recirculating 20 l tanks (10 animals per tank), with three replicates per treatment. After an 8 week experimental period, fish fed the diets containing 10 and 15% SPH showed significantly better performance in terms of final body weight, weight gain (%), mean daily weight gain (mg day?1), specific growth ratio and feed conversion ratio than those fed the control diet (fishmeal as protein source) and higher‐SPH diets. It is concluded that shrimp head hydrolysate is a promising alternative protein source for tilapia feeding, improving growth ratio at dietary inclusion levels as high as 15%. In addition, the diets with added shrimp silage protein were well accepted by the fish, which avidly consumed the feed during the experiment. © 2002 Society of Chemical Industry 相似文献
10.