全文获取类型
收费全文 | 134179篇 |
免费 | 13303篇 |
国内免费 | 7318篇 |
专业分类
电工技术 | 9703篇 |
技术理论 | 4篇 |
综合类 | 10036篇 |
化学工业 | 20389篇 |
金属工艺 | 8397篇 |
机械仪表 | 9006篇 |
建筑科学 | 10008篇 |
矿业工程 | 4311篇 |
能源动力 | 3950篇 |
轻工业 | 8775篇 |
水利工程 | 2942篇 |
石油天然气 | 7273篇 |
武器工业 | 1523篇 |
无线电 | 16102篇 |
一般工业技术 | 14883篇 |
冶金工业 | 6358篇 |
原子能技术 | 1541篇 |
自动化技术 | 19599篇 |
出版年
2024年 | 607篇 |
2023年 | 1940篇 |
2022年 | 3630篇 |
2021年 | 5174篇 |
2020年 | 3942篇 |
2019年 | 3284篇 |
2018年 | 3635篇 |
2017年 | 4236篇 |
2016年 | 3958篇 |
2015年 | 5352篇 |
2014年 | 6761篇 |
2013年 | 7955篇 |
2012年 | 9576篇 |
2011年 | 10238篇 |
2010年 | 9232篇 |
2009年 | 8845篇 |
2008年 | 8624篇 |
2007年 | 8232篇 |
2006年 | 8193篇 |
2005年 | 6782篇 |
2004年 | 5022篇 |
2003年 | 4474篇 |
2002年 | 4438篇 |
2001年 | 3920篇 |
2000年 | 3059篇 |
1999年 | 2765篇 |
1998年 | 2077篇 |
1997年 | 1771篇 |
1996年 | 1559篇 |
1995年 | 1269篇 |
1994年 | 1074篇 |
1993年 | 732篇 |
1992年 | 543篇 |
1991年 | 460篇 |
1990年 | 342篇 |
1989年 | 277篇 |
1988年 | 223篇 |
1987年 | 157篇 |
1986年 | 122篇 |
1985年 | 65篇 |
1984年 | 42篇 |
1983年 | 33篇 |
1982年 | 38篇 |
1981年 | 25篇 |
1980年 | 29篇 |
1979年 | 15篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1976年 | 14篇 |
1975年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
Xiaoyan Qiu Yongqiang Zhang Haitao Wu Rui Yang Jun Yang Rongjuan Liu Yong Liu Zhiping Zhou Tongfan Hao Yijing Nie 《Polymer International》2019,68(2):218-224
The crystallization of capped ultrathin polymer films is closely dependent on film thickness and interfacial interaction. Using dynamic Monte Carlo simulations, the crystallization behaviors of polymer films confined between two substrates were investigated. The crystallization rate of confined polymers is reduced with high interfacial interactions. Above a critical strength of interfacial interaction, polymer crystallization in the thin film is inhibited within the simulation time scales. An increase in film thickness leads to a rise in critical interfacial interaction. In thicker films, the chains have more space to change conformation to form crystal stems. In addition, there are fewer absorbed segments in confined chains for the thicker films, and thus the chains have stronger ability to adjust their conformation. Therefore an increase in film thickness can cause a reduction in the entropic barrier required for the formation of crystals and thus an increase in the critical interfacial interaction. © 2018 Society of Chemical Industry 相似文献
34.
Thermoresponsive behavior and rheology of SiO2–hyaluronic acid/poly(N‐isopropylacrylamide) (NaHA/PNIPAm) core–shell structured microparticles
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
35.
36.
分别使用AutoCAD、StruCAD 3D及Solid Works软件在石油井架、底座校核中进行强度分析,AutoCAD软件的主要优势在工程制图领域,兼具强度分析功能,适用于单个形状比较规则的型材强度分析;StruCAD 3D是专门针对大型钢结构进行强度校核的分析软件,具有强大的计算处理功能,兼具风载处理能力,在处理大型、复杂结构的时候应优先考虑应用该软件;当遇到需要进行实体造型、模拟实际情况进行校核时,SolidWorks软件较为方便,可以直观地看到应变情况。 相似文献
37.
38.
Xiaohui Hu Li Cheng Yan Hong Zhaofeng Li Caiming Li Zhengbiao Gu 《International Journal of Food Science & Technology》2021,56(8):4149-4158
Incorporating high level of potato flour into wheat flour enhances nutritional values of bread but induces a series of problems that lead to the decline of the bread quality. To overcome the barrier, wheat gluten and carboxymethylcellulose (CMC) were added into potato–wheat composite flour to improve dough machinability and bread quality. The rheological properties, thermo-mechanical properties and microstructures of dough were investigated. The results showed that the interaction between gluten and CMC mitigated the discontinuity of gluten matrix and gluten protein aggregation caused by the addition of potato flour, which yielded a more branched and compact gluten network. The compact three-dimensional viscoelastic structure induced improvements of gas retention capacity and dough stability, making it mimic the machinability properties of wheat flour dough. Bread qualities were apparently improved with the combined use of 4% gluten and 6% CMC, of which specific volume increased by 42.86%, and simultaneously, hardness reduced by 75.93%. 相似文献
39.
In vivo Kinetic Biodistribution of Nano‐Sized Outer Membrane Vesicles Derived from Bacteria
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Su Chul Jang Sae Rom Kim Yae Jin Yoon Kyong‐Su Park Ji Hyun Kim Jaewook Lee Oh Youn Kim Eun‐Jeong Choi Dae‐Kyum Kim Dong‐Sic Choi Yoon‐Keun Kim Jaesung Park Dolores Di Vizio Yong Song Gho 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(4):456-461
Evaluation of kinetic distribution and behaviors of nanoparticles in vivo provides crucial clues into their roles in living organisms. Extracellular vesicles are evolutionary conserved nanoparticles, known to play important biological functions in intercellular, inter‐species, and inter‐kingdom communication. In this study, the first kinetic analysis of the biodistribution of outer membrane vesicles (OMVs)—bacterial extracellular vesicles—with immune‐modulatory functions is performed. OMVs, injected intraperitoneally, spread to the whole mouse body and accumulate in the liver, lung, spleen, and kidney within 3 h of administration. As an early systemic inflammation response, increased levels of TNF‐α and IL‐6 are observed in serum and bronchoalveolar lavage fluid. In addition, the number of leukocytes and platelets in the blood is decreased. OMVs and cytokine concentrations, as well as body temperature are gradually decreased 6 h after OMV injection, in concomitance with the formation of eye exudates, and of an increase in ICAM‐1 levels in the lung. Following OMV elimination, most of the inflammatory signs are reverted, 12 h post‐injection. However, leukocytes in bronchoalveolar lavage fluid are increased as a late reaction. Taken together, these results suggest that OMVs are effective mediators of long distance communication in vivo. 相似文献
40.