全文获取类型
收费全文 | 86966篇 |
免费 | 6622篇 |
国内免费 | 2763篇 |
学科分类
工业技术 | 96351篇 |
出版年
2024年 | 217篇 |
2023年 | 1339篇 |
2022年 | 1950篇 |
2021年 | 3209篇 |
2020年 | 2462篇 |
2019年 | 2251篇 |
2018年 | 2689篇 |
2017年 | 2860篇 |
2016年 | 2580篇 |
2015年 | 3137篇 |
2014年 | 4083篇 |
2013年 | 5219篇 |
2012年 | 5215篇 |
2011年 | 5908篇 |
2010年 | 4984篇 |
2009年 | 4764篇 |
2008年 | 4681篇 |
2007年 | 4363篇 |
2006年 | 4366篇 |
2005年 | 3935篇 |
2004年 | 2747篇 |
2003年 | 2487篇 |
2002年 | 2240篇 |
2001年 | 1959篇 |
2000年 | 2098篇 |
1999年 | 2341篇 |
1998年 | 2269篇 |
1997年 | 1769篇 |
1996年 | 1693篇 |
1995年 | 1382篇 |
1994年 | 1105篇 |
1993年 | 848篇 |
1992年 | 627篇 |
1991年 | 501篇 |
1990年 | 402篇 |
1989年 | 324篇 |
1988年 | 279篇 |
1987年 | 207篇 |
1986年 | 155篇 |
1985年 | 139篇 |
1984年 | 96篇 |
1983年 | 76篇 |
1982年 | 56篇 |
1981年 | 53篇 |
1980年 | 53篇 |
1979年 | 28篇 |
1978年 | 27篇 |
1977年 | 34篇 |
1976年 | 43篇 |
1975年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 578 毫秒
71.
72.
Neural Processing Letters - The beta processes (BP) is a powerful nonparametric tool in feature learning, which is often used as the prior of Bernoulli process for choosing features from a feature... 相似文献
73.
74.
75.
76.
Hwansoo Lee Dongwon Lim Hyerin Kim Andrew P. Ciganek 《Behaviour & Information Technology》2015,34(1):45-56
Many e-commerce companies collect users’ personal data for marketing purposes despite privacy concerns. Information-collecting companies often offer a monetary reward to users to alleviate privacy concerns and ease the collection of personal information. This study focused on the negative effects of monetary rewards on both information privacy concerns (IPC) and information disclosure. A survey approach was used to collect data and 370 final responses were analysed using a two-way analysis of variance and a binomial logistic regression model. The results show that monetary rewards increase IPC when an information-collecting company requires sensitive information. Additional results indicate that building trust is a more effective way of collecting personal data. This study identifies how organisations can best execute information-collection activities and contributes additional insights for academia and practitioners. 相似文献
77.
340管线矫直机是太原重工成熟产品,在国内占有较大市场,并出口印度、印尼、缅甸、埃及等国际市场。出口印度矫直机在质保期内出现主缸裂纹问题,为探明问题原因并杜绝类似情况发生,快开机构设计静强度分析、疲劳强度分析及生产加工过程等方面探查裂纹原因并提出几点预防措施。 相似文献
78.
A device able to electrokinetically concentrate cationic samples has many potential medical and industrial applications, but until now has remained undeveloped due to the lack of a commercial anion-permselective material leading to a prohibitively complex fabrication procedure. Herein, a novel multiscale-porous anion exchange membrane (MP-AEM) that enables the convenient and scalable electrokinetic concentration of cationic species is proposed. A mechanically enhanced multiscale-porous structure with a solid framework is realized by adopting polyester resin as an additive to overcome the intrinsic limitations of the AEM material. The scalable MP-AEM-embedded electrokinetic concentrator is devised based on the peculiar properties of the MP-AEM that for allow both ion and fluid transport. With the MP-AEM, the concentrator is fabricated in a highly streamlined manner consisting only of a simple insertion and assembly. The concentration performance of the MP-AEM-embedded electrokinetic concentrator is demonstrated with a positively charged fluorescent dye and a fluorescein-labeled protein, and the results show enrichment factors of 250 and 500, respectively. The MP-AEM makes cationic electrokinetic concentration more accessible and scalable, thereby enabling further progress in a wide range of fields. 相似文献
79.
80.
Qiang Xia Tao Feng Xiaowei Lou Ying Wang Yangying Sun Daodong Pan Jinxuan Cao 《International Journal of Food Science & Technology》2020,55(2):669-680
As a decisive attribute, flavour could be influenced by HP treatments through multiple physical and chemical pathways within the high pressure (HP)-assisted meat curing process. This investigation aimed to identify the major pathway influencing volatile flavour patterns of two representative vinasse-cured duck (VCD) products with HP treatments (150–300 MPa/15 min), including wet and dry types, by employing headspace fingerprinting as an untargeted approach. Results suggested that HP treatments greatly lowered moisture contents and increased Warner-Bratzler shear force and thiobarbituric acid reactive substances of the cured samples. According to multivariate models, the volatile flavour patterns of the HP-processed VCD could be clearly separated from the unprocessed samples, but the VCD pressurised at different intensities represented similar volatile fingerprinting, which was validated by e-nose analysis. The discriminant analysis (OPLS-DA) model outlined vinasse-derived ethanol, acetic acid, 3-methyl-1-butanol, 2-methyl-1-butanol, phenethyl alcohol and 2-methyl-3-octanone as the major discriminant aromas across the unpressurised and pressurised samples. 相似文献