全文获取类型
收费全文 | 3022篇 |
免费 | 52篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 13篇 |
综合类 | 1篇 |
化学工业 | 449篇 |
金属工艺 | 45篇 |
机械仪表 | 24篇 |
建筑科学 | 38篇 |
矿业工程 | 3篇 |
能源动力 | 93篇 |
轻工业 | 142篇 |
水利工程 | 8篇 |
石油天然气 | 14篇 |
无线电 | 158篇 |
一般工业技术 | 236篇 |
冶金工业 | 1591篇 |
原子能技术 | 12篇 |
自动化技术 | 253篇 |
出版年
2022年 | 24篇 |
2021年 | 39篇 |
2020年 | 34篇 |
2019年 | 24篇 |
2018年 | 44篇 |
2017年 | 34篇 |
2016年 | 33篇 |
2015年 | 25篇 |
2014年 | 31篇 |
2013年 | 95篇 |
2012年 | 63篇 |
2011年 | 97篇 |
2010年 | 73篇 |
2009年 | 64篇 |
2008年 | 79篇 |
2007年 | 69篇 |
2006年 | 46篇 |
2005年 | 30篇 |
2004年 | 41篇 |
2003年 | 30篇 |
2002年 | 46篇 |
2001年 | 36篇 |
2000年 | 38篇 |
1999年 | 65篇 |
1998年 | 431篇 |
1997年 | 241篇 |
1996年 | 193篇 |
1995年 | 108篇 |
1994年 | 102篇 |
1993年 | 111篇 |
1992年 | 36篇 |
1991年 | 36篇 |
1990年 | 50篇 |
1989年 | 50篇 |
1988年 | 60篇 |
1987年 | 42篇 |
1986年 | 39篇 |
1985年 | 42篇 |
1984年 | 23篇 |
1983年 | 20篇 |
1982年 | 23篇 |
1981年 | 25篇 |
1980年 | 24篇 |
1979年 | 11篇 |
1978年 | 19篇 |
1977年 | 49篇 |
1976年 | 89篇 |
1975年 | 11篇 |
1974年 | 12篇 |
1973年 | 13篇 |
排序方式: 共有3080条查询结果,搜索用时 0 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.
Abraham G. Alvarado Rosaura Hernández-Montelongo Martin Rabelero Lourdes A. Pérez-Carrillo Jorge E. Puig Francisco López-Serrano 《Polymer Engineering and Science》2020,60(2):223-232
A simple but comprehensive model considering homogeneous and micellar nucleation, coagulation, entry of radicals to particles and to micelles and radicals' exit from particles, is presented. The model is validated, in a starved semicontinuous heterophase polymerization of ethyl methacrylate, at three monomer addition rates. The model accurately describes the overall and instantaneous conversion, the average particle density and diameter, and the number and weight average molar masses evolutions over time. It is found that even though the average number of radicals is much smaller than 0.5, the system is not 0-1. An empirical function was used to describe the gel effect. The homogeneous nucleation was the prevailing mechanism for particle formation and large exit rates of radicals were observed. POLYM. ENG. SCI., 60: 223–232, 2019. © 2019 Society of Plastics Engineers 相似文献
4.
DC Reynolds CE Leak KK Bajaj CE Stutz RL Jones KR Evans PW Yu WM Theis 《Canadian Metallurgical Quarterly》1989,40(9):6210-6217
5.
6.
7.
8.
Michelle Abraham 《电子产品世界》2008,(7)
数字视频编码和解码芯片目前需求量很大.在未来几年里,这种芯片的市场将更加强劲地增长.推动这个市场增长的因素有三个:一个是全球范围的从模拟电视向数字电视的过渡,这种过渡将刺激数字接收机和基础设施设备的需求;另一个因素是手机、便携式播放机和汽车内的移动视频功能日益流行;第三个因素是数字视频标准的持续发展将推动对提供高性能芯片的新需求. 相似文献
9.
Paul I. Dalven James R. Hildebrandt Abraham Shamir Anthony J. Laccetti Leonard T. Hodgins Harry P. Gregor 《应用聚合物科学杂志》1985,30(3):1113-1132
Various high molecular weight copolymers of acrylonitrile and a vinyl comonomer containing an aryl amine, a pyridine, or an aliphatic hydroxyl group were synthesized via slurry polymerization techniques so as to contain from 1 to 15 mol % functional comonomer. The comonomer content was quantitated by ultraviolet absorbance, base titration of acid polymer salts, and/or relative chemical reactivity with trichloro-s-triazine. Thin films were cast from copolymer solutions, coagulated into unsupported ultrafiltration membrances, and characterized with respect to both water permeability and pore size distribution. Analysis by size exclusion chromatography of the membrane permeate of a pool of dextran fractions yielded a continuous distribution curve for membrane pore size over the range 1.5 to 70 nm. The ultrafiltration membranes were used for protein immobilization after appropriate chemical activation. The three distinct types of functional copolymers gave comparable results for α-chymotrypsin, with protein weight loadings of 6–12% and 40–65% retention of enzymatic specific activity. 相似文献
10.
PJ Jenkins MA Satta M Simmgen WM Drake C Williamson DG Lowe K Britton SL Chew RV Thakker GM Besser 《Canadian Metallurgical Quarterly》1997,47(6):747-751
We report a patient with a metastatic parathyroid carcinoma and medullary carcinoma of the thyroid. This patient represents a variation of the multiple endocrine neoplasia syndrome (MEN) type 2A. There was no evidence of a phaeochromocytoma. The case illustrates the difficulties that may be encountered in localising the source of PTH secretion; the patient underwent four unsuccessful exploratory operations of the neck and mediastinum before further investigations revealed a single metastatic deposit of parathyroid carcinoma involving the first thoracic vertebra. PCR amplification and sequencing of the RET oncogene from the metastatic parathyroid carcinoma and genomic DNA revealed a heterozygous mutation (Cys634Tyr) in exon 11, as has previously been described to occur in MEN 2A. In addition, loss of tumour heterozygosity was demonstrated at loci from chromosomes 1, 2, 3p, 13q and 16p. This represents the first report of a parathyroid carcinoma in a MEN2A patient, in which the multiple allelic deletions are consistent with the generalised losses observed in aggressive tumours. 相似文献