全文获取类型
收费全文 | 2023篇 |
免费 | 197篇 |
国内免费 | 14篇 |
专业分类
电工技术 | 26篇 |
综合类 | 34篇 |
化学工业 | 438篇 |
金属工艺 | 63篇 |
机械仪表 | 122篇 |
建筑科学 | 61篇 |
矿业工程 | 6篇 |
能源动力 | 82篇 |
轻工业 | 295篇 |
水利工程 | 14篇 |
石油天然气 | 24篇 |
无线电 | 250篇 |
一般工业技术 | 434篇 |
冶金工业 | 124篇 |
原子能技术 | 12篇 |
自动化技术 | 249篇 |
出版年
2024年 | 6篇 |
2023年 | 34篇 |
2022年 | 31篇 |
2021年 | 80篇 |
2020年 | 65篇 |
2019年 | 69篇 |
2018年 | 94篇 |
2017年 | 108篇 |
2016年 | 76篇 |
2015年 | 63篇 |
2014年 | 105篇 |
2013年 | 151篇 |
2012年 | 132篇 |
2011年 | 146篇 |
2010年 | 97篇 |
2009年 | 107篇 |
2008年 | 93篇 |
2007年 | 79篇 |
2006年 | 77篇 |
2005年 | 55篇 |
2004年 | 36篇 |
2003年 | 50篇 |
2002年 | 53篇 |
2001年 | 36篇 |
2000年 | 31篇 |
1999年 | 30篇 |
1998年 | 56篇 |
1997年 | 46篇 |
1996年 | 39篇 |
1995年 | 24篇 |
1994年 | 22篇 |
1993年 | 17篇 |
1992年 | 18篇 |
1991年 | 12篇 |
1990年 | 13篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1972年 | 2篇 |
排序方式: 共有2234条查询结果,搜索用时 28 毫秒
1.
Hyun Sun Choi Yun Kee Jo Gwang-Noh Ahn Kye Il Joo Dong-Pyo Kim Hyung Joon Cha 《Advanced functional materials》2021,31(46):2104602
The esophagus is a tubular-shaped muscular organ where swallowed fluids and muscular contractions constitute a highly dynamic environment. The turbulent, coordinated processes that occur through the oropharyngeal conduit can often compromise targeted administration of therapeutic drugs to a lesion, significantly reducing therapeutic efficacy. Here, magnetically guidable drug vehicles capable of strongly adhering to target sites using a bioengineered mussel adhesive protein (MAP) to achieve localized delivery of therapeutic drugs against the hydrodynamic physiological conditions are proposed. A suite of highly uniform microparticles embedded with iron oxide (IO) nanoparticles (MAP@IO MPs) is microfluidically fabricated using the genipin-mediated covalent cross-linking of bioengineered MAP. The MAP@IO MPs are successfully targeted to a specific region and prolongedly retained in the tubular-structured passageway. In particular, orally administered MAP@IO MPs are effectively captured in the esophagus in vivo in a magnetically guidable manner. Moreover, doxorubicin (DOX)-loaded MAP@IO MPs exhibit a sustainable DOX release profile, effective anticancer therapeutic activity, and excellent biocompatibility. Thus, the magnetically guidable locomotion and robust underwater adhesive properties of the proteinaceous soft microbots can provide an intelligent modular approach for targeted locoregional therapeutics delivery to a specific lesion site in dynamic fluid-associated tubular organs such as the esophagus. 相似文献
2.
3.
Laise Cedraz Pinto Tainá Pinheiro de Oliveira Rayane de Souza Nathane Brito Ferreira Santos Luis Fernandes Pereira Santos Andréa de Assis Santos Teodora Xavier dos Santos Carolaine Teixeira Santos Catarina de Jesus Nunes Isis Barbosa Costa Amanda Catariny de Oliveira Marly Silveira Santos Clícia Maria de Jesus Benevides Mariângela Vieira Lopes 《Journal of Food Processing and Preservation》2021,45(2):e15113
4.
Song Won Joon Youn Gyu Seong Cha Dong Jin 《Journal of Mechanical Science and Technology》2021,35(9):4261-4270
Journal of Mechanical Science and Technology - Here, a procedure that uses in-situ data recorded by two microphones placed inside an operating gas turbine combustor to determine the reflection... 相似文献
5.
Telecommunication Systems - In this paper, we derive upper bound of Packet Error Probability (PEP), upper bound of delay and lower bound of throughput in cognitive radio networks. Our analysis is... 相似文献
6.
Lipase production by solid‐state fermentation of olive pomace in tray‐type and pressurized bioreactors 下载免费PDF全文
7.
8.
Sowoon Seo Yunjeong Song Sun Mi Gu Hyun Kyu Min Jin Tae Hong Hye Jin Cha Jaesuk Yun 《International journal of molecular sciences》2020,21(23)
Background: Epilepsy is a chronic neurological disorder characterized by the recurrence of seizures. One-third of patients with epilepsy may not respond to antiseizure drugs. Purpose: We aimed to examine whether D-limonene, a cyclic monoterpene, exhibited any antiseizure activity in the pentylenetetrazole (PTZ)-induced kindling mouse model and in vitro. Methods: PTZ kindling mouse model was established by administering PTZ (30 mg/kg) intraperitoneally to mice once every 48 h. We performed immunoblot blots, immunohistochemistry (IHC), and high-performance liquid chromatography (HPLC) analysis after the behavioral study. Results: An acute injection of PTZ (60 mg/kg) induced seizure in mice, while pretreatment with D-limonene inhibited PTZ-induced seizure. Repeated administration of PTZ (30 mg/kg) increased the seizure score gradually in mice, which was reduced in D-limonene (10 mg/kg)-pretreated group. In addition, D-limonene treatment increased glutamate decarboxylase-67 (GAD-67) expression in the hippocampus. Axonal sprouting of hippocampal neurons after kindling was inhibited by D-limonene pretreatment. Moreover, D-limonene reduced the expression levels of Neuronal PAS Domain Protein 4 (Npas4)-induced by PTZ. Furthermore, the adenosine A2A antagonist and ZM241385 inhibited anticonvulsant activity and gamma-aminobutyric acid (GABA)ergic neurotransmission-induced by D-limonene. Conclusion: These results suggest that D-limonene exhibits anticonvulsant activity through modulation of adenosine A2A receptors on GABAergic neuronal function. SCH58261相似文献
9.
Textured (K0.47Na0.51Li0.02)(Nb0.8Ta0.2)O3 (KNLNT20) piezoelectric ceramics were prepared using NaNb1?xTaxO3 templates. The highest degree of grain orientation (97%) and piezoelectric constant (342 pC/N) were obtained upon adding 3 wt% of the NaNb0.8Ta0.2O3 (NNT20) template and sintering at 1150 °C for 1 h. Back-scattered scanning electron micrographs of the textured KNLNT20 samples sintered at 1150 °C for 1 h indicated the presence of templates similar in size to the original ones within the cores of the textured grains. The peak value of the dielectric constant corresponding to the NNT20 core decreased after prolonged holding at 1150 °C, owing to a decrease in the size of the NNT20 core because of the interdiffusion of K, Na, and Li ions between the NNT20 core and KNLNT20 shell. This interdiffusion also decreased the piezoelectric constant, d33 value of the textured KNLNT20 samples by inducing a change in the chemical composition of the shell region. 相似文献
10.
Samia Tássia Andrade Maciel Alexander Andrey Lopes da Silva Yasmin Guimarães Pedro Cristiano Nunes da Silva Leôncio Diógenes Tavares Câmara João Monnerat Araújo Ribeiro de Almeida Emerson Schwingel Ribeiro Gabriel Francisco da Silva Lisiane Santos Freitas Donato Alexandre Gomes Aranda 《化学工程与技术》2020,43(11):2149-2159
The catalytic hydrolysis of soybean oil was used as an alternative for the production of monoglycerides (MG) and diglycerides (DG). The reactions were conducted in a stainless-steel tubular reactor in the temperature range of 240–290 °C, on niobium phosphate (NBP) and niobium oxide (NBO) as catalysts. In the hydrolysis reactions at 270 °C, the maximum selectivities of the products of interest were obtained at 22 % MG and 48 % DG for the reaction with NBP, and 7 % MG and 33 % DG with NBO, for 59 % and 36 % of triglyceride conversion in 10 min, respectively. The proposed kinetic model presented a good fit of the theoretical model with the experimental data, showing that the previous hypotheses considered for the mechanism development are suitable for describing the kinetics of soybean oil hydrolysis. 相似文献