全文获取类型
收费全文 | 12481篇 |
免费 | 891篇 |
国内免费 | 43篇 |
专业分类
电工技术 | 249篇 |
综合类 | 20篇 |
化学工业 | 2568篇 |
金属工艺 | 488篇 |
机械仪表 | 802篇 |
建筑科学 | 288篇 |
矿业工程 | 5篇 |
能源动力 | 549篇 |
轻工业 | 1151篇 |
水利工程 | 55篇 |
石油天然气 | 14篇 |
武器工业 | 3篇 |
无线电 | 2081篇 |
一般工业技术 | 2807篇 |
冶金工业 | 780篇 |
原子能技术 | 137篇 |
自动化技术 | 1418篇 |
出版年
2023年 | 139篇 |
2022年 | 84篇 |
2021年 | 351篇 |
2020年 | 302篇 |
2019年 | 317篇 |
2018年 | 421篇 |
2017年 | 414篇 |
2016年 | 478篇 |
2015年 | 391篇 |
2014年 | 592篇 |
2013年 | 807篇 |
2012年 | 874篇 |
2011年 | 1048篇 |
2010年 | 719篇 |
2009年 | 818篇 |
2008年 | 720篇 |
2007年 | 576篇 |
2006年 | 511篇 |
2005年 | 454篇 |
2004年 | 397篇 |
2003年 | 350篇 |
2002年 | 342篇 |
2001年 | 255篇 |
2000年 | 212篇 |
1999年 | 203篇 |
1998年 | 340篇 |
1997年 | 252篇 |
1996年 | 161篇 |
1995年 | 163篇 |
1994年 | 118篇 |
1993年 | 110篇 |
1992年 | 74篇 |
1991年 | 55篇 |
1990年 | 50篇 |
1989年 | 45篇 |
1988年 | 33篇 |
1987年 | 32篇 |
1986年 | 27篇 |
1985年 | 22篇 |
1984年 | 19篇 |
1983年 | 17篇 |
1982年 | 15篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 12篇 |
1978年 | 5篇 |
1977年 | 18篇 |
1976年 | 23篇 |
1975年 | 6篇 |
1973年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 31 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.
Shin Hansub Sim Sungyong Kwon Hyukyoon Hwang Sangheum Lee Younho 《International Journal of Information Security》2022,21(1):25-36
International Journal of Information Security - This paper deals with a well-known problem in the area of the smudge attacks: when a user draws a pattern to unlock the pattern lock on a smartphone... 相似文献
4.
Dr. Ala Jo Mingi Kim Dr. Jong In Kim Jaeyoung Ha Yoon Soo Hwang Hyunsung Nam Dr. Injae Hwang Dr. Jae Bum Kim Prof. Seung Bum Park 《ChemMedChem》2021,16(7):1104-1115
Obesity has become a pandemic that threatens the quality of life and discovering novel therapeutic agents that can reverse obesity and obesity-related metabolic disorders are necessary. Here, we aimed to identify new anti-obesity agents using a phenotype-based approach. We performed image-based high-content screening with a fluorogenic bioprobe (SF44), which visualizes cellular lipid droplets (LDs), to identify initial hit compounds. A structure-activity relationship study led us to yield a bioactive compound SB1501, which reduces cellular LDs in 3T3-L1 adipocytes without cytotoxicity. SB1501 induced the expression of gene products that regulate mitochondrial biogenesis and fatty acid oxidation in 3T3-L1 adipocytes. Daily treatment with SB1501 improved the metabolic states of db/db mice by reducing body fat mass, adipose tissue mass, food intake, and increasing glucose tolerance. The anti-obesity effect of SB1501 may result from perturbation of the PGC-1α–UCP1 regulatory axis in inguinal white adipose tissue and brown adipose tissue. These data suggest the therapeutic potential of SB1501 as an anti-obesity agent via modulating mitochondrial activities. 相似文献
5.
6.
Achieving a functional cure for chronic hepatitis B virus (HBV) infection or complete elimination of HBV covalently closed circular DNA (cccDNA) has been challenging in the treatment of patients with chronic HBV infection. Although novel antivirals are being investigated, improving HBV-specific adaptive immune responses is also important for durable viral clearance. Tissue-resident memory CD8+ T (TRM) cells were recently reported as a T-cell population that resides in peripheral tissues and does not recirculate. TRM cells have been studied in the livers of mice and humans. Liver TRM cells have distinct characteristics compared to T cells in peripheral blood or other tissues, which may be associated with the unique microenvironment of the liver. In this review, we describe the characteristics of liver TRM cells and their implications in chronic HBV infection. We emphasize that liver TRM cells can be an immunotherapeutic target for the treatment of chronic HBV infection. 相似文献
7.
Ohjin Kwon Xiaoqian Cai Wentao Qu Feng Liu Jadwiga Szydłowska Ewa Gorecka Moon Jong Han Dong Ki Yoon Silvio Poppe Carsten Tschierske 《Advanced functional materials》2021,31(28):2102271
First examples of multichain (polycatenar) compounds, based on the π-conjugated [1]benzothieno[3,2-b]benzothiophene unit are designed, synthesized, and their soft self-assembly and charge carrier mobility are investigated. These compounds, terminated by the new fan-shaped 2-brominated 3,4,5-trialkoxybenzoate moiety, form bicontinuous cubic liquid crystalline (LC) phases with helical network structure over extremely wide temperature ranges (>200 K), including ambient temperature. Compounds with short chains show an achiral cubic phase with the double network, which upon increasing the chain length, is at first replaced by a tetragonal 3D phase and then by a mirror symmetry is broken triple network cubic phase. In the networks, the capability of bypassing defects provides enhanced charge carrier mobility compared to imperfectly aligned columnar phases, and the charge transportation is non-dispersive, as only rarely observed for LC materials. At the transition to a semicrystalline helical network phase, the conductivity is further enhanced by almost one order of magnitude. In addition, a mirror symmetry broken isotropic liquid phase is formed beside the 3D phases, which upon chain elongation is removed and replaced by a hexagonal columnar LC phase. 相似文献
8.
This paper proposes an approach to improve the performance of no-reference video quality assessment for sports videos with dynamic motion scenes using an efficient spatiotemporal model. In the proposed method, we divide the video sequences into video blocks and apply a 3D shearlet transform that can efficiently extract primary spatiotemporal features to capture dynamic natural motion scene statistics from the incoming video blocks. The concatenation of a deep residual bidirectional gated recurrent neural network and logistic regression is used to learn the spatiotemporal correlation more robustly and predict the perceptual quality score. In addition, conditional video block-wise constraints are incorporated into the objective function to improve quality estimation performance for the entire video. The experimental results show that the proposed method extracts spatiotemporal motion information more effectively and predicts the video quality with higher accuracy than the conventional no-reference video quality assessment methods. 相似文献
9.
10.
Min-Woo Kim Yong-Il Kim Chanwoo Park Ali Aldalbahi Hamdah S.Alanazi Seongpil An Alexander L.Yarin Sam S.Yoon 《材料科学技术学报》2021,85(26):44-55
As global air pollution becomes increasingly severe,various types of fibrous filters have been devel-oped to improve air filter performance.However,fibrous filters have limitations such as high packing density that generally causes high-pressure drop and ultimately deterioration in the filtration effi-ciency.High-pressure particulate matter precipitators are limited in terms of scope for commercialization because they require high voltage supplies and ozone generators.In this study,we develop fibrous fil-ters with enhanced durability and improved performance using metallized microfibers decorated with metal-organic-framework(MOF)nanocrystals.Not only does the efficiency of the developed filters remain at or above 97%for 0.50-1.5 μm PMs but the durability also significantly increases.In addi-tion,using the water purification ability of the MOF,we explore the dye degradation effect of the hybrid microfibers by immersing them into Rhodamine B aqueous solution.In such an experiment the Rho-damine B aqueous solution is completely purified by the presence of the hybrid microfibers under the UV irradiation. 相似文献