全文获取类型
收费全文 | 26277篇 |
免费 | 762篇 |
国内免费 | 103篇 |
专业分类
电工技术 | 842篇 |
综合类 | 98篇 |
化学工业 | 4256篇 |
金属工艺 | 1506篇 |
机械仪表 | 2009篇 |
建筑科学 | 461篇 |
矿业工程 | 301篇 |
能源动力 | 362篇 |
轻工业 | 1039篇 |
水利工程 | 401篇 |
石油天然气 | 859篇 |
武器工业 | 11篇 |
无线电 | 3195篇 |
一般工业技术 | 6414篇 |
冶金工业 | 2538篇 |
原子能技术 | 493篇 |
自动化技术 | 2357篇 |
出版年
2023年 | 125篇 |
2022年 | 322篇 |
2021年 | 654篇 |
2020年 | 511篇 |
2019年 | 697篇 |
2018年 | 1290篇 |
2017年 | 1347篇 |
2016年 | 1563篇 |
2015年 | 977篇 |
2014年 | 1412篇 |
2013年 | 1855篇 |
2012年 | 1740篇 |
2011年 | 1698篇 |
2010年 | 1519篇 |
2009年 | 1737篇 |
2008年 | 1593篇 |
2007年 | 1441篇 |
2006年 | 1210篇 |
2005年 | 781篇 |
2004年 | 524篇 |
2003年 | 323篇 |
2002年 | 329篇 |
2001年 | 276篇 |
2000年 | 563篇 |
1999年 | 447篇 |
1998年 | 595篇 |
1997年 | 487篇 |
1996年 | 139篇 |
1995年 | 108篇 |
1994年 | 94篇 |
1993年 | 79篇 |
1992年 | 62篇 |
1991年 | 52篇 |
1990年 | 52篇 |
1989年 | 33篇 |
1988年 | 21篇 |
1987年 | 24篇 |
1986年 | 23篇 |
1985年 | 32篇 |
1984年 | 32篇 |
1983年 | 25篇 |
1982年 | 15篇 |
1980年 | 24篇 |
1979年 | 27篇 |
1978年 | 24篇 |
1977年 | 18篇 |
1976年 | 30篇 |
1975年 | 15篇 |
1969年 | 24篇 |
1968年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
1.
Ava Kwong Cecilia Y. S. Ho Vivian Y. Shin Chun Hang Au Tsun Leung Chan Edmond S. K. Ma 《International journal of molecular sciences》2021,22(2)
The germline carrier of the BRCA1 pathogenic mutation has been well proven to confer an increased risk of breast and ovarian cancer. Despite BRCA1 biallelic pathogenic mutations being extremely rare, they have been reported to be embryonically lethal or to cause Fanconi anemia (FA). Here we describe a patient who was a 48-year-old female identified with biallelic pathogenic mutations of the BRCA1 gene, with no or very subtle FA-features. She was diagnosed with ovarian cancer and breast cancer at the ages of 43 and 44 and had a strong family history of breast and gynecological cancers. 相似文献
2.
Suk-Young Song Soonil Pyo Sungchul Choi Hee Sang Oh Jung Hwa Seo Ji Hea Yu Ahreum Baek Yoon-Kyum Shin Hoo Young Lee Ja Young Choi Sung-Rae Cho 《International journal of molecular sciences》2021,22(7)
Hypoxic–ischemic encephalopathy (HIE) is a devastating neonatal brain condition caused by lack of oxygen and limited blood flow. Environmental enrichment (EE) is a classic paradigm with a complex stimulation of physical, cognitive, and social components. EE can exert neuroplasticity and neuroprotective effects in immature brains. However, the exact mechanism of EE on the chronic condition of HIE remains unclear. HIE was induced by a permanent ligation of the right carotid artery, followed by an 8% O2 hypoxic condition for 1 h. At 6 weeks of age, HIE mice were randomly assigned to either standard cages or EE cages. In the behavioral assessments, EE mice showed significantly improved motor performances in rotarod tests, ladder walking tests, and hanging wire tests, compared with HIE control mice. EE mice also significantly enhanced cognitive performances in Y-maze tests. Particularly, EE mice showed a significant increase in Cav 2.1 (P/Q type) and presynaptic proteins by molecular assessments, and a significant increase of Cav 2.1 in histological assessments of the cerebral cortex and hippocampus. These results indicate that EE can upregulate the expression of the Cav 2.1 channel and presynaptic proteins related to the synaptic vesicle cycle and neurotransmitter release, which may be responsible for motor and cognitive improvements in HIE. 相似文献
3.
4.
Golubev N. V. Ignat’eva E. S. Maurus A. A. Ziyatdinova M. Z. Lopatina E. V. Lorenzi R. Paleari A. Sigaev V. N. 《Glass and Ceramics》2021,77(11-12):415-418
Glass and Ceramics - The influence of Al2O3 as an additive and the heat-treatment regime on the luminescence spectra of gallate glass-ceramics was investigated. It is shown that its luminescence... 相似文献
5.
Shalunov A. V. Khmelev V. N. Terent’ev S. A. Nesterov V. A. 《Journal of Engineering Physics and Thermophysics》2022,95(4):909-917
Journal of Engineering Physics and Thermophysics - The possibility of intensifying the drying of materials by noncontact ultrasonic action at a frequency of 22 kHz at sound pressure levels up to... 相似文献
6.
Sofia Melchior Sonia Calligaris Marilena Marino Francesca D’Este Giorgio Honsell Maria Cristina Nicoli Nadia Innocente 《International Journal of Food Science & Technology》2022,57(5):3106-3115
This research aimed at studying the potential use of monoglyceride (MG) structured emulsions (MSEs) as delivery and protective systems for probiotic bacteria in Ricotta cheese. To this purpose, a low-fat commercial Ricotta cheese was added with MSEs formulated with milk, as water phase, and sunflower oil (MSE-SO) or anhydrous milk fat (MSE-AMF), as lipid phase. A commercial whole milk Ricotta cheese (W-RC) was considered as reference. A probiotic Lacticaseibacillus rhamnosus strain was inoculated as free cells in W-RC or embedded into the MSEs and added to the low-fat Ricotta at the same reference fat content. After physico-chemical characterisation, L. rhamnosus viability and sample destructuring behaviour upon in vitro digestion were evaluated. At the end of in vitro digestion, both W-RC and sample containing MSE-SO were unable to protect cells. By contrast, sample with AMF ensured a sufficient probiotic viability, even after 14 days of storage at 4 °C. This result was attributed to system composition and structure. During the gastric phase, the presence of caseins and MG-AMF mixed structures induced the formation of clots, entrapping and protecting cells against the acidic pH of the stomach, as confirmed by confocal micrographs and particle size. During the intestinal phase, cell viability was guaranteed by the formation of mixed micelles promoted by MG. It was demonstrated that microbial cells located near MG structures where they found protection. 相似文献
7.
Journal of Computer and Systems Sciences International - A method for the synthesis of fast finite state machines on programmable logic integrated circuits such as field-programmable gate arrays is... 相似文献
8.
Chudina O. V. Prikhod’ko V. M. Simonov D. S. Bringulis P. 《Russian Engineering Research》2022,42(11):1192-1194
Russian Engineering Research - Hybrid surface hardening consisting of quenching with inductive heating by high-frequency current and subsequent ultrasonic surface plastic deformation is considered.... 相似文献
9.
Seredin P. V. Radam Ali Obaid Goloshchapov D. L. Len’shin A. S. Buylov N. S. Barkov K. A. Nesterov D. N. Mizerov A. M. Timoshnev S. N. Nikitina E. V. Arsentyev I. N. Sharafidinov Sh. Kukushkin S. A. Kasatkin I. A. 《Semiconductors》2022,56(4):253-258
Semiconductors - Abstract—In our work, we carry out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen-plasma activation on a hybrid... 相似文献
10.
Journal of Materials Science - We attempted melt-spinning and investigated the compatibility and thermal decomposition of a mixture comprising polysilsesquioxane and polycarbosilane for the purpose... 相似文献