全文获取类型
收费全文 | 58863篇 |
免费 | 15259篇 |
国内免费 | 75篇 |
专业分类
电工技术 | 1031篇 |
综合类 | 33篇 |
化学工业 | 21547篇 |
金属工艺 | 1225篇 |
机械仪表 | 2057篇 |
建筑科学 | 2129篇 |
矿业工程 | 6篇 |
能源动力 | 1750篇 |
轻工业 | 8751篇 |
水利工程 | 382篇 |
石油天然气 | 66篇 |
无线电 | 10144篇 |
一般工业技术 | 15536篇 |
冶金工业 | 2259篇 |
原子能技术 | 299篇 |
自动化技术 | 6982篇 |
出版年
2024年 | 12篇 |
2023年 | 280篇 |
2022年 | 348篇 |
2021年 | 955篇 |
2020年 | 1863篇 |
2019年 | 3527篇 |
2018年 | 3662篇 |
2017年 | 3919篇 |
2016年 | 4446篇 |
2015年 | 4356篇 |
2014年 | 4657篇 |
2013年 | 6294篇 |
2012年 | 4135篇 |
2011年 | 4125篇 |
2010年 | 3918篇 |
2009年 | 3794篇 |
2008年 | 3267篇 |
2007年 | 2842篇 |
2006年 | 2471篇 |
2005年 | 2055篇 |
2004年 | 1953篇 |
2003年 | 1879篇 |
2002年 | 1831篇 |
2001年 | 1601篇 |
2000年 | 1497篇 |
1999年 | 902篇 |
1998年 | 828篇 |
1997年 | 509篇 |
1996年 | 450篇 |
1995年 | 304篇 |
1994年 | 215篇 |
1993年 | 191篇 |
1992年 | 142篇 |
1991年 | 127篇 |
1990年 | 97篇 |
1989年 | 107篇 |
1988年 | 84篇 |
1987年 | 78篇 |
1986年 | 64篇 |
1985年 | 54篇 |
1984年 | 48篇 |
1983年 | 44篇 |
1982年 | 36篇 |
1981年 | 33篇 |
1980年 | 34篇 |
1979年 | 17篇 |
1977年 | 29篇 |
1976年 | 36篇 |
1975年 | 17篇 |
1974年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Hong Sae Jin Park Nam Il Hwang Dae Keun Yi Tae Gyu Eum Hyang Lan 《Food science and biotechnology》2022,31(6):669-679
Food Science and Biotechnology - Various hilling materials (rice hulls, pine sawdust, and perlite) were compared to produce sprout vegetables using beach silvertop (Glehnia littoralis Fr. Schm. ex... 相似文献
2.
International Journal of Information Security - Machine learning techniques have been widely used and shown remarkable performance in various fields. Along with the widespread utilization of... 相似文献
3.
Bijan Nasri‐Nasrabadi Akif Kaynak Shayan Seyedin Zahra Komeily‐Nia Abbas Z Kouzani 《Polymer International》2019,68(5):922-928
Recent advances in three‐dimensional (3D) printing have enabled the fabrication of interesting structures which are not achievable using traditional fabrication approaches. The 3D printing of carbon microtube composite inks allows fabrication of conductive structures for practical applications in soft robotics and tissue engineering. However, it is challenging to achieve 3D printed structures from solution‐based composite inks, which requires an additional process to solidify the ink. Here, we introduce a wet 3D printing technique which uses a coagulation bath to fabricate carbon microtube composite structures. We show that through a facile nanogrooving approach which introduces cavitation and channels on carbon microtubes, enhanced interfacial interactions with a chitosan polymer matrix are achieved. Consequently, the mechanical properties of the 3D printed composites improve when nanogrooved carbon microtubes are used, compared to untreated microtubes. We show that by carefully controlling the coagulation bath, extrusion pressure, printing distance and printed line distance, we can 3D print composite lattices which are composed of well‐defined and separated printed lines. The conductive composite 3D structures with highly customised design presented in this work provide a suitable platform for applications ranging from soft robotics to smart tissue engineering scaffolds. © 2019 Society of Chemical Industry 相似文献
4.
5.
Cho-Yi Chen Masaoki Kawasumi Tien-Yun Lan Chi-Lam Poon Yi-Sian Lin Pin-Jou Wu Yao-Chung Chen Bing-Hong Chen Cheng-Hsien Wu Jeng-Fan Lo Rueyhung Roc Weng Yi-Chen Sun Kai-Feng Hung 《International journal of molecular sciences》2021,22(1)
Endoplasmic reticulum (ER) stress response is an adaptive program to cope with cellular stress that disturbs the function and homeostasis of ER, which commonly occurs during cancer progression to late stage. Late-stage cancers, mostly requiring chemotherapy, often develop treatment resistance. Chemoresistance has been linked to ER stress response; however, most of the evidence has come from studies that correlate the expression of stress markers with poor prognosis or demonstrate proapoptosis by the knockdown of stress-responsive genes. Since ER stress in cancers usually persists and is essentially not induced by genetic manipulations, we used low doses of ER stress inducers at levels that allowed cell adaptation to occur in order to investigate the effect of stress response on chemoresistance. We found that prolonged tolerable ER stress promotes mesenchymal–epithelial transition, slows cell-cycle progression, and delays the S-phase exit. Consequently, cisplatin-induced apoptosis was significantly decreased in stress-adapted cells, implying their acquisition of cisplatin resistance. Molecularly, we found that proliferating cell nuclear antigen (PCNA) ubiquitination and the expression of polymerase η, the main polymerase responsible for translesion synthesis across cisplatin-DNA damage, were up-regulated in ER stress-adaptive cells, and their enhanced cisplatin resistance was abrogated by the knockout of polymerase η. We also found that a fraction of p53 in stress-adapted cells was translocated to the nucleus, and that these cells exhibited a significant decline in the level of cisplatin-DNA damage. Consistently, we showed that the nuclear p53 coincided with strong positivity of glucose-related protein 78 (GRP78) on immunostaining of clinical biopsies, and the cisplatin-based chemotherapy was less effective for patients with high levels of ER stress. Taken together, this study uncovers that adaptation to ER stress enhances DNA repair and damage tolerance, with which stressed cells gain resistance to chemotherapeutics. 相似文献
6.
7.
Karolina Storesund Francine Amon Anne Steen‐Hansen Shayesteh Haghighatpanah Ida Larsson 《火与材料》2021,45(1):181-190
The aim of this exploratory study has been to investigate the fire properties and environmental aspects of different upholstery material combinations, mainly for domestic applications. An analysis of the sustainability and circularity of selected textiles, along with lifecycle assessment, is used to qualitatively evaluate materials from an environmental perspective. The cone calorimeter was the primary tool used to screen 20 different material combinations from a fire performance perspective. It was found that textile covers of conventional fibres such as wool, cotton and polyester, can be improved by blending them with fire resistant speciality fibres. A new three‐dimensional web structure has been examined as an alternative padding material, showing preliminary promising fire properties with regard to ignition time, heat release rates and smoke production. 相似文献
8.
9.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018) 下载免费PDF全文
10.
Food Science and Biotechnology - Aluminum based reflective nanolens arrays were developed via a series of aluminum electropolishing and anodization steps with subsequent selective dissolution of... 相似文献