全文获取类型
收费全文 | 21784篇 |
免费 | 2067篇 |
国内免费 | 866篇 |
专业分类
电工技术 | 1225篇 |
技术理论 | 3篇 |
综合类 | 1377篇 |
化学工业 | 3638篇 |
金属工艺 | 1195篇 |
机械仪表 | 1476篇 |
建筑科学 | 1991篇 |
矿业工程 | 773篇 |
能源动力 | 628篇 |
轻工业 | 1216篇 |
水利工程 | 350篇 |
石油天然气 | 1521篇 |
武器工业 | 125篇 |
无线电 | 2283篇 |
一般工业技术 | 2656篇 |
冶金工业 | 1059篇 |
原子能技术 | 280篇 |
自动化技术 | 2921篇 |
出版年
2024年 | 273篇 |
2023年 | 487篇 |
2022年 | 674篇 |
2021年 | 913篇 |
2020年 | 771篇 |
2019年 | 633篇 |
2018年 | 701篇 |
2017年 | 780篇 |
2016年 | 671篇 |
2015年 | 842篇 |
2014年 | 1127篇 |
2013年 | 1229篇 |
2012年 | 1398篇 |
2011年 | 1441篇 |
2010年 | 1307篇 |
2009年 | 1167篇 |
2008年 | 1150篇 |
2007年 | 1118篇 |
2006年 | 1172篇 |
2005年 | 1108篇 |
2004年 | 656篇 |
2003年 | 572篇 |
2002年 | 513篇 |
2001年 | 478篇 |
2000年 | 451篇 |
1999年 | 588篇 |
1998年 | 459篇 |
1997年 | 394篇 |
1996年 | 359篇 |
1995年 | 316篇 |
1994年 | 244篇 |
1993年 | 144篇 |
1992年 | 132篇 |
1991年 | 119篇 |
1990年 | 87篇 |
1989年 | 71篇 |
1988年 | 54篇 |
1987年 | 31篇 |
1986年 | 31篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 14篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
世界各国面临气候变化的挑战,人们将目光投向最清洁的化石能源——天然气。天然气也是汽车理想的替代燃料,以开拓天然气零售和直分销业务作为燃气业务拓展主攻方向,抢占先机积极推进天然气加气网点建设投营和天然气直分销业务,快速提高天然气市场占有率已成为广东石油的发展战略。 相似文献
13.
14.
本文以工程实例作为分析基础,重点探讨了框架剪力墙结构建筑的常用施工技术,包括钢筋工程、模板工程、混凝土工程的施工技术及轻骨料砼空心砌块的施工工艺。 相似文献
15.
16.
TRPV4 Promotes Metastasis in Melanoma by Regulating Cell Motility through Cytoskeletal Rearrangement
Shuai Huang Suyun Yu Rui Deng Huan Liu Yushi Ding Yifan Sun Wenxing Chen Aiyun Wang Zhonghong Wei Yin Lu 《International journal of molecular sciences》2022,23(23)
The abnormal expression of Transient Receptor Potential cation channel subfamily V member 4 (TRPV4) is closely related to the progression of multiple tumors. In addition, TRPV4 is increasingly being considered a potential target for cancer therapy, especially in tumor metastasis prevention. However, the biological correlation between TRPV4 and tumor metastasis, as well as the specific role of TRPV4 in malignant melanoma metastasis, is poorly understood. In this study, we aimed to examine the role of TRPV4 in melanoma metastasis through experiments and clinical data analysis, and the underlying anticancer mechanism of Baicalin, a natural compound, and its inhibitory effect on TRPV4 with in vivo and in vitro experiments. Our findings suggested that TRPV4 promotes metastasis in melanoma by regulating cell motility via rearranging the cytoskeletal, and Baicalin can inhibit cancer metastasis, whose mechanisms reverse the recruitment of activated cofilin to leading-edge protrusion and the increasing phosphorylation level of cortactin, which is provoked by TRPV4 activation. 相似文献
17.
Xuesong Deng Yahui Wang Lifang Ma Zhigang Li Zongsheng Chen Xiangyin Lv Yajing Chang Yi Liu Jiaming Shi 《International journal of molecular sciences》2022,23(23)
Carbon-based carbides have attracted tremendous attention for electromagnetic energy attenuation due to their adjustable dielectric properties, oxidation resistance, and good chemical stability. Herein, we reasonably regulate the growth of dopamine hydrochloride on the surface of the Mo-glycerate (Mo-GL) microsphere and then transform the resultant Mo-polydopamine (Mo-PD) microsphere into a dual-shell Mo2C/C (DS-Mo2C/C) microsphere in a high-temperature pyrolysis process under an inert atmosphere. It is found that the pyrolysis temperature plays an important role in the graphitization degree of the carbon matrix and internal architecture. The fabrication of a dual-shell structure can be propitious to the optimization of impedance matching, and the introduction of Mo2C nanoparticles also prompts the accumulation of polarization loss. When the pyrolysis temperature reaches 800 °C, the optimized composite of DS-Mo2C/C-800 exhibits good EM absorption performance in the frequency range of 2.0–18.0 GHz. DS-Mo2C/C-800′s qualified bandwidth can reach 4.4 GHz at a matching thickness of 1.5 mm, and the integrated qualified bandwidth (QBW) even exceeds 14.5 GHz with a thickness range of 1.5–5.0 mm. The positive effects of the dual-shell structure and Mo2C nanoparticles on EM energy attenuation may render the DS-Mo2C/C microsphere as a promising candidate for lightweight and broad bandwidth EM absorption materials in the future. 相似文献
18.
Qing Chen Zhenru Guo Xiaoli Shi Meiqiao Wei Yazhen Fan Jing Zhu Ting Zheng Yan Wang Li Kong Mei Deng Xinyou Cao Jirui Wang Yuming Wei Qiantao Jiang Yunfeng Jiang Guoyue Chen Youliang Zheng Pengfei Qi 《International journal of molecular sciences》2022,23(18)
Grain yield (GY) and grain protein content (GPC) are important traits for wheat breeding and production; however, they are usually negatively correlated. The Q gene is the most important domestication gene in cultivated wheat because it influences many traits, including GY and GPC. Allelic variations in the Q gene may positively affect both GY and GPC. Accordingly, we characterized two new Q alleles (Qs1 and Qc1-N8) obtained through ethyl methanesulfonate-induced mutagenesis. Compared with the wild-type Q allele, Qs1 contains a missense mutation in the sequence encoding the first AP2 domain, whereas Qc1-N8 has two missense mutations: one in the sequence encoding the second AP2 domain and the other in the microRNA172-binding site. The Qs1 allele did not significantly affect GPC or other processing quality parameters, but it adversely affected GY by decreasing the thousand kernel weight and grain number per spike. In contrast, Qc1-N8 positively affected GPC and GY by increasing the thousand kernel weight and grain number per spike. Thus, we generated novel germplasm relevant for wheat breeding. A specific molecular marker was developed to facilitate the use of the Qc1-N8 allele in breeding. Furthermore, our findings provide useful new information for enhancing cereal crops via non-transgenic approaches. 相似文献
19.
Israa M. Shamkh Mohammed Al-Majidi Ahmed Hassen Shntaif Peter Tan Deng Kai Ngoc Nh-Pham Ishrat Rahman Dalia Hamza Mohammad Shahbaz Khan Maii S. Elsharayidi Eman T. Salah Abdullah Haikal Modupe Akintomiwa Omoniyi Mahmoud A. Abdalrahman Tomasz M. Karpinski 《International journal of molecular sciences》2022,23(21)
In recent years, novel strategies to control insects have been based on protease inhibitors (PIs). In this regard, molecular docking and molecular dynamics simulations have been extensively used to investigate insect gut proteases and the interactions of PIs for the development of resistance against insects. We, herein, report an in silico study of (disodium 5′-inosinate and petunidin 3-glucoside), (calcium 5′-guanylate and chlorogenic acid), chlorogenic acid alone, (kaempferol-3,7-di-O-glucoside with hyperoside and delphinidin 3-glucoside), and (myricetin 3′-glucoside and hyperoside) as potential inhibitors of acetylcholinesterase receptors, actin, α-tubulin, arginine kinase, and histone receptor III subtypes, respectively. The study demonstrated that the inhibitors are capable of forming stable complexes with the corresponding proteins while also showing great potential for inhibitory activity in the proposed protein-inhibitor combinations. 相似文献
20.
Aurelie Dos Santos Ning Lyu Alis Balayan Rob Knight Katherine Sun Zhuo Yuzhao Sun Jianjiang Xu Martha L. Funderburgh James L. Funderburgh Sophie X. Deng 《International journal of molecular sciences》2022,23(21)
In addition to their therapeutic potential in regenerative medicine, human corneal stromal stem cells (CSSCs) could serve as a powerful tool for drug discovery and development. Variations from different donors, their isolation method, and their limited life span in culture hinder the utility of primary human CSSCs. To address these limitations, this study aims to establish and characterize immortalized CSSC lines (imCSSC) generated from primary human CSSCs. Primary CSSCs (pCSSC), isolated from human adult corneoscleral tissue, were transduced with ectopic expression of hTERT, c-MYC, or the large T antigen of the Simian virus 40 (SV40T) to generate imCSSC. Cellular morphology, proliferation capacity, and expression of CSSCs specific surface markers were investigated in all cell lines, including TNFAIP6 gene expression levels in vitro, a known biomarker of in vivo anti-inflammatory efficacy. SV40T-overexpressing imCSSC successfully extended the lifespan of pCSSC while retaining a similar morphology, proliferative capacity, multilineage differentiation potential, and anti-inflammatory properties. The current study serves as a proof-of-concept that immortalization of CSSCs could enable a large-scale source of CSSC for use in regenerative medicine. 相似文献