全文获取类型
收费全文 | 7241篇 |
免费 | 473篇 |
国内免费 | 169篇 |
学科分类
工业技术 | 7883篇 |
出版年
2023年 | 95篇 |
2022年 | 148篇 |
2021年 | 281篇 |
2020年 | 162篇 |
2019年 | 191篇 |
2018年 | 214篇 |
2017年 | 218篇 |
2016年 | 197篇 |
2015年 | 242篇 |
2014年 | 285篇 |
2013年 | 389篇 |
2012年 | 376篇 |
2011年 | 465篇 |
2010年 | 363篇 |
2009年 | 347篇 |
2008年 | 380篇 |
2007年 | 312篇 |
2006年 | 284篇 |
2005年 | 217篇 |
2004年 | 149篇 |
2003年 | 142篇 |
2002年 | 148篇 |
2001年 | 140篇 |
2000年 | 140篇 |
1999年 | 167篇 |
1998年 | 295篇 |
1997年 | 190篇 |
1996年 | 134篇 |
1995年 | 99篇 |
1994年 | 89篇 |
1993年 | 92篇 |
1992年 | 53篇 |
1991年 | 41篇 |
1990年 | 40篇 |
1989年 | 41篇 |
1988年 | 47篇 |
1987年 | 41篇 |
1986年 | 44篇 |
1985年 | 30篇 |
1984年 | 39篇 |
1983年 | 36篇 |
1982年 | 27篇 |
1981年 | 20篇 |
1980年 | 31篇 |
1979年 | 24篇 |
1978年 | 25篇 |
1977年 | 19篇 |
1976年 | 56篇 |
1975年 | 24篇 |
1974年 | 18篇 |
排序方式: 共有7883条查询结果,搜索用时 15 毫秒
1.
Feng Wenran Li Zhen Chen Yingying Chen Jinyang Lang Haoze Wan Jianghong Gao Yan Dong Haitao 《Journal of Materials Science》2022,57(3):1881-1889
Journal of Materials Science - Although chalcogenide materials continue to generate considerable interest due to great potentials for various optoelectronic devices, annealing for a long time in... 相似文献
2.
Deborah Oliveira De Fusco Leonardo Lucas Madaleno Vanildo Luiz Del Bianchi Aline da Silva Bernardo Rafael Roberto Assis Gustavo Henrique de Almeida Teixeira 《International Journal of Food Science & Technology》2019,54(7):2416-2424
Alcohol-free beer with isotonic properties is getting more popular and its production can be carried out by different production strategies; however, interrupted fermentation is still a challenge. Therefore, the objective of this study was to develop a low-alcohol isotonic beer (<0.5% v/v) by interrupted fermentation. Moreover, the major objective is to compare the developed product to commercial beverages (sports drinks, ‘Pilsen' regular beer, alcohol-free beers and low-alcohol isotonic beer). The beverages were evaluated based on pH, alcohol content (% v/v), total titratable acidity (mEq L−1), osmolality (mOsmol kg−1), bitterness International Bitterness Units, colour European Brewery Convention, total phenolic compounds (mg L−1 gallic acid), reducing and total sugars (%) and Na and K contents (mg L−1). The developed low-alcohol isotonic beer presented characteristics similar to sports drinks, with the advantage of being richer in phenolic compounds and suitable osmolality. Despite salts were added in its formulation, the grades attributed to all beers employed in the sensory evaluation, as well as the purchase intention did not present significant differences. 相似文献
3.
4.
Xu Lang Bhandari Saurabh Chen Jiming Glasgow Jonathan Mavrikakis Manos 《Topics in Catalysis》2020,63(7-8):762-776
Topics in Catalysis - Palladium has been shown to be an effective catalyst for chloroform hydrodechlorination, which serves as a promising treatment method for industrial chloroform waste. To... 相似文献
5.
6.
7.
Shanquan Chen Sicong Wei Fei Jin Shanming Ke Xierong Zeng Lang Chen Chuanwei Huang 《Ceramics International》2018,44(12):13695-13698
From the perspectives of scientific researches and practical applications, it is desirable to explore high operating temperature ferromagnetic films. The effect of biaxial strain on magnetic properties of (110)-oriented La0.7Sr0.3MnO3 films was studied. High quality La0.7Sr0.3MnO3 films were grown on (110)-oriented perovskite single crystal substrates using pulsed laser deposition, varying substrate-induced misfit strains from ??2.27–0.75%. A remarkable enhancement of Curie temperature has been achieved for (110)-oriented La0.7Sr0.3MnO3 films clamped with small misfit strains (i.e., grown on LAST (110)). The enhanced Curie temperature of (110)-oriented La0.7Sr0.3MnO3 films could be attributed to the misfit strain between the films and the underlying substrates and may have technological implication for applications at high temperature environments. 相似文献
8.
9.
10.
Shanchieh Jay Yang Gustavo de Veciana 《Networking, IEEE/ACM Transactions on》2004,12(2):349-360
With a view on improving user-perceived performance on networks supporting best effort flows, e.g., multimedia/data file transfers, we propose a family of bandwidth allocation criteria that depends on the residual work of on-going transfers. Analysis and simulations show that allocating bandwidth in this fashion can significantly improve the user-perceived delay, bit transmission delay, and throughput over traditional approaches, e.g., by 58% on an 80% loaded linear network. A simple implementation based on TCP Reno, exemplifies how one might approach practically realizing such gains. We discuss several other advantages of incorporating such differentiation at the transport level. In particular we make the case that favoring small transfers combined with user impatience or peak rate constraints, both of which are natural mechanisms for users to express the utility of completing transfers, offers a lightweight approach to achieving good overall network goodput and/or utility for best effort networks. 相似文献