全文获取类型
收费全文 | 19878篇 |
免费 | 1621篇 |
国内免费 | 768篇 |
专业分类
电工技术 | 1048篇 |
技术理论 | 4篇 |
综合类 | 1027篇 |
化学工业 | 3599篇 |
金属工艺 | 901篇 |
机械仪表 | 1219篇 |
建筑科学 | 1330篇 |
矿业工程 | 527篇 |
能源动力 | 571篇 |
轻工业 | 1097篇 |
水利工程 | 290篇 |
石油天然气 | 1125篇 |
武器工业 | 127篇 |
无线电 | 2686篇 |
一般工业技术 | 2657篇 |
冶金工业 | 1028篇 |
原子能技术 | 189篇 |
自动化技术 | 2842篇 |
出版年
2024年 | 205篇 |
2023年 | 345篇 |
2022年 | 538篇 |
2021年 | 754篇 |
2020年 | 568篇 |
2019年 | 522篇 |
2018年 | 588篇 |
2017年 | 602篇 |
2016年 | 574篇 |
2015年 | 688篇 |
2014年 | 899篇 |
2013年 | 1220篇 |
2012年 | 1131篇 |
2011年 | 1274篇 |
2010年 | 990篇 |
2009年 | 1025篇 |
2008年 | 1003篇 |
2007年 | 964篇 |
2006年 | 1014篇 |
2005年 | 914篇 |
2004年 | 610篇 |
2003年 | 596篇 |
2002年 | 519篇 |
2001年 | 442篇 |
2000年 | 525篇 |
1999年 | 579篇 |
1998年 | 528篇 |
1997年 | 458篇 |
1996年 | 441篇 |
1995年 | 317篇 |
1994年 | 300篇 |
1993年 | 213篇 |
1992年 | 170篇 |
1991年 | 139篇 |
1990年 | 125篇 |
1989年 | 95篇 |
1988年 | 77篇 |
1987年 | 52篇 |
1986年 | 44篇 |
1985年 | 39篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1982年 | 31篇 |
1981年 | 22篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1971年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Hui Min Tan He Cheng Yew Chung Tang Sai Mun Leong Poh Yin Teo Chi Kuen Lee Victor Kwan Min Lee Susan Swee-Shan Hue 《International journal of molecular sciences》2022,23(14)
Adipocytic tumors are the most common subtype of soft tissue tumors. In current clinical practice, distinguishing benign lipomas from well-differentiated liposarcomas (WDLPS), as well as dedifferentiated liposarcomas (DDLPS) from their morphologic mimics, remains a significant diagnostic challenge. This is especially so when examining small biopsy samples and without the aid of additional ancillary tests. Recognizing the important role that microRNAs (miRNAs) play in tumorigenesis and their potential utility in tumor classification, we analyzed routine clinical tissue samples of benign and malignant lipomatous tumors, as well as other sarcoma mimics, to identify distinguishing miRNA-based signatures that can aid in the differential diagnosis of these entities. We discovered a 6-miRNA signature that separated lipomas from WDLPS with high confidence (AUC of 0.963), as well as a separate 6-miRNA signature that distinguished DDLPS from their more aggressive histologic mimics (AUC of 0.740). Functional enrichment analysis unveiled possible mechanistic involvement of these predictive miRNAs in adipocytic cancer-related biological processes and pathways such as PI3K/AKT/mTOR and MAPK signaling, further supporting the relevance of these miRNAs as biomarkers for adipocytic tumors. Our results demonstrate that miRNA expression profiling may potentially be used as an adjunctive tool for the diagnosis of benign and malignant adipocytic tumors. Further validation studies are warranted. 相似文献
43.
Jing Yuan Tan Muhammed Haiqal Low Yunxin Chen Francesca Lorraine Wei Inng Lim 《International journal of molecular sciences》2022,23(13)
Chimeric antigen receptor (CAR) T cell therapy has ushered in a new era in cancer treatment. Remarkable outcomes have been demonstrated in patients with previously untreatable relapsed/refractory hematological malignancies. However, optimizing efficacy and reducing the risk of toxicities have posed major challenges, limiting the success of this therapy. The tumor microenvironment (TME) plays an important role in CAR T cell therapy’s effectiveness and the risk of toxicities. Increasing research studies have also identified various biomarkers that can predict its effectiveness and risk of toxicities. In this review, we discuss the various aspects of the TME and biomarkers that have been implicated thus far and discuss the role of creating scoring systems that can aid in further refining clinical applications of CAR T cell therapy and establishing a safe and efficacious personalised medicine for individuals. 相似文献
44.
45.
46.
从采集的图像数据中提取特征,这是图像的模式识别中最重要的问题之一,解决的方法通常依赖于对具体应用的经验知识,对同样的任务,人的视觉系统却以一种普适的方法去完成.本文从人的心理学特性出发,导出信号特征的全局性质,然后讨论由局域信号构成总体特征的统计方法,进而借助于信号的Lebesgue积分表示与测不准原理提出一种普适性的特征表示方法MSR.实验结果表明,对图像信号MSR是适合于并行计算的有效逼近. 相似文献
47.
Yikai Chen Yang Tan Silvia Tessarini Sanjay Sampath 《Journal of Thermal Spray Technology》2013,22(2-3):110-115
Spray parameters play an important role on the microstructure and properties of plasma-sprayed coatings. Parameters such as spray distance, plasma gas flow and current, raster speed, and spray angle all can be varied. In this paper, an integrated study to investigate the effects and influences of spray angle on properties of yttria-stabilized zirconia coatings was carried out with spray angles of 60°, 75°, and 90° (to the substrate surface). In situ coating property sensor based on beam curvature measurements was used to measure the evolving stress and elastic moduli of the resultant coatings and combined with other characterization tools for thermo-physical property and microstructure analysis, such as laser flash and scanning electron microscopy. The results indicate that the coating with 60° spray angle had the lowest thermal conductivity and more compliant structure. This study seeks to understand the mechanism for this effect and will provide important insight into parametric sensitivities on complex spray parts. 相似文献
48.
Jiahua Zhang Peishuang Yao Wenli Han Ying Luo Yuke Li Yang Yang Hui Xia Zhihao Chen Qi Chen Hong Wang Lu Yang Huan Li Congli Hu Haifeng Huang Zhe Peng Xiaodan Tan Miaomiao Li Junqing Yang 《International journal of molecular sciences》2022,23(11)
A growing body of research suggests that inflammatory insult contributes to the etiology of central nervous system diseases, such as depression, Alzheimer’s disease, and so forth. However, the effect of prenatal systemic inflammation exposure on offspring brain development and cerebral susceptibility to inflammatory insult remains unknown. In this study, we utilized the prenatal inflammatory insult model in vivo and the neuronal damage model in vitro. The results obtained show that prenatal maternal inflammation exacerbates LPS-induced memory impairment, neuronal necrosis, brain inflammatory response, and significantly increases protein expressions of COX-2, DP2, APP, and Aβ, while obviously decreasing that of DP1 and the exploratory behaviors of offspring rats. Meloxicam significantly inhibited memory impairment, neuronal necrosis, oxidative stress, and inflammatory response, and down-regulated the expressions of APP, Aβ, COX-2, and DP2, whereas significantly increased exploring behaviors and the expression of DP1 in vivo. Collectively, these findings suggested that maternal inflammation could cause offspring suffering from inflammatory and behavioral disorders and increase the susceptibility of offspring to cerebral pathological factors, accompanied by COX-2/PGD-2/DPs pathway activation, which could be ameliorated significantly by COX-2 inhibitor meloxicam treatment. 相似文献
49.
Ziyang Zhang Tianran Li Yujie Wu Yinjun Jia Congwei Tan Xintong Xu Guanrui Wang Juan Lv Wei Zhang Yuhan He Jing Pei Cheng Ma Guoqi Li Haizheng Xu Luping Shi Hailin Peng Huanglong Li 《Advanced materials (Deerfield Beach, Fla.)》2019,31(3)
Concomitance of diverse synaptic plasticity across different timescales produces complex cognitive processes. To achieve comparable cognitive complexity in memristive neuromorphic systems, devices that are capable of emulating short‐term (STP) and long‐term plasticity (LTP) concomitantly are essential. In existing memristors, however, STP and LTP can only be induced selectively because of the inability to be decoupled using different loci and mechanisms. In this work, the first demonstration of truly concomitant STP and LTP is reported in a three‐terminal memristor that uses independent physical phenomena to represent each form of plasticity. The emerging layered material Bi2O2Se is used for memristors for the first time, opening up the prospects for ultrathin, high‐speed, and low‐power neuromorphic devices. The concerted action of STP and LTP allows full‐range modulation of the transient synaptic efficacy, from depression to facilitation, by stimulus frequency or intensity, providing a versatile device platform for neuromorphic function implementation. A heuristic recurrent neural circuitry model is developed to simulate the intricate “sleep–wake cycle autoregulation” process, in which the concomitance of STP and LTP is posited as a key factor in enabling this neural homeostasis. This work sheds new light on the development of generic memristor platforms for highly dynamic neuromorphic computing. 相似文献
50.
Flexible Photodetectors: Low‐Temperature Heteroepitaxy of 2D PbI2/Graphene for Large‐Area Flexible Photodetectors (Adv. Mater. 36/2018) 下载免费PDF全文