全文获取类型
收费全文 | 6844篇 |
免费 | 833篇 |
国内免费 | 289篇 |
专业分类
电工技术 | 86篇 |
综合类 | 564篇 |
化学工业 | 1832篇 |
金属工艺 | 77篇 |
机械仪表 | 222篇 |
建筑科学 | 332篇 |
矿业工程 | 25篇 |
能源动力 | 63篇 |
轻工业 | 1805篇 |
水利工程 | 40篇 |
石油天然气 | 43篇 |
武器工业 | 15篇 |
无线电 | 351篇 |
一般工业技术 | 411篇 |
冶金工业 | 258篇 |
原子能技术 | 79篇 |
自动化技术 | 1763篇 |
出版年
2025年 | 36篇 |
2024年 | 126篇 |
2023年 | 174篇 |
2022年 | 555篇 |
2021年 | 482篇 |
2020年 | 266篇 |
2019年 | 217篇 |
2018年 | 193篇 |
2017年 | 236篇 |
2016年 | 249篇 |
2015年 | 273篇 |
2014年 | 401篇 |
2013年 | 444篇 |
2012年 | 438篇 |
2011年 | 471篇 |
2010年 | 417篇 |
2009年 | 412篇 |
2008年 | 420篇 |
2007年 | 409篇 |
2006年 | 337篇 |
2005年 | 262篇 |
2004年 | 224篇 |
2003年 | 189篇 |
2002年 | 121篇 |
2001年 | 106篇 |
2000年 | 77篇 |
1999年 | 64篇 |
1998年 | 54篇 |
1997年 | 48篇 |
1996年 | 45篇 |
1995年 | 49篇 |
1994年 | 34篇 |
1993年 | 20篇 |
1992年 | 24篇 |
1991年 | 20篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 5篇 |
1987年 | 9篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1964年 | 3篇 |
1963年 | 3篇 |
1961年 | 3篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有7966条查询结果,搜索用时 15 毫秒
161.
Xinlun Liu Xudan Kou Shichao Bai Yufeng Luo Zhenyu Wang Lincai Xie Pingchuan Deng Hong Zhang Changyou Wang Yajuan Wang Jixin Zhao Wanquan Ji 《International journal of molecular sciences》2022,23(11)
The grain aphid Sitobion avenae (Fabricius) is one of the most destructive pests of wheat (Triticum aestivum). Deployment of resistant wheat germplasm appears as an excellent solution for this problem. Elite bread wheat cultivars only have limited resistance to this pest. The present study was carried out to investigate the potential of the tetraploid wheat (Triticum turgidum) variety Lanmai, which showed high resistance to S. avenae at both seedling and adult plant stages, as a source of resistance genes. Based on apterous adult aphids’ fecundity tests and choice bioassays, Lanmai has been shown to display antixenosis and antibiosis. Suppression subtractive hybridization (SSH) was employed to identify and isolate the putative candidate defense genes in Lanmai against S. avenae infestation. A total of 134 expressed sequence tags (ESTs) were identified and categorized based on their putative functions. RT-qPCR analysis of 30 selected genes confirmed their differential expression over time between the resistant wheat variety Lanmai and susceptible wheat variety Polan305 during S. avenae infestation. There were 11 genes related to the photosynthesis process, and only 3 genes showed higher expression in Lanmai than in Polan305 after S. avenae infestation. Gene expression analysis also revealed that Lanmai played a critical role in salicylic acid and jasmonic acid pathways after S. avenae infestation. This study provided further insights into the role of defense signaling networks in wheat resistance to S. avenae and indicates that the resistant tetraploid wheat variety Lanmai may provide a valuable resource for aphid tolerance improvement in wheat. 相似文献
162.
163.
Soudeh Ghafouri-Fard Tayyebeh Khoshbakht Bashdar Mahmud Hussen Sepideh Kadkhoda Mohammad Taheri Arash Tafrishinejad 《International journal of molecular sciences》2022,23(1)
miR-149 is an miRNA with essential roles in carcinogenesis. This miRNA is encoded by the MIR149 gene on 2q37.3. The miR-149 hairpin produces miR-149-5p and miR-149-3p, which are the “guide” and the sister “passenger” strands, respectively. Deep sequencing experiments have shown higher prevalence of miR-149-5p compared with miR-149-3p. Notably, both oncogenic and tumor suppressive roles have been reported for miR-149-5p. In this review, we summarize the impact of miR-149-5p in the tumorigenesis and elaborate mechanisms of its involvement in this process in a variety of neoplastic conditions based on three lines of evidence, i.e., in vitro, in vivo and clinical settings. 相似文献
164.
165.
166.
Hyunjong Byun Jiyeon Park Benedict U. Fabia Joshua Bingwa Mihn Hieu Nguyen Haeshin Lee Jung Hoon Ahn 《International journal of molecular sciences》2022,23(12)
Many heterologous proteins can be secreted by bacterial ATP-binding cassette (ABC) transporters, provided that they are fused with the C-terminal signal sequence, but some proteins are not secretable even though they carry the right signal sequence. The invention of a method to secrete these non-secretable proteins would be valuable both for understanding the secretory physiology of ABC transporters and for industrial applications. Herein, we postulate that cationic “supercharged” regions within the target substrate protein block the secretion by ABC transporters. We also suggest that the secretion of such substrate proteins can be rescued by neutralizing those cationic supercharged regions via structure-preserving point mutageneses. Surface-protruding, non-structural cationic amino acids within the cationic supercharged regions were replaced by anionic or neutral hydrophilic amino acids, reducing the cationic charge density. The examples of rescued secretions we provide include the spike protein of SARS-CoV-2, glutathione-S-transferase, streptavidin, lipase, tyrosinase, cutinase, growth factors, etc. In summary, our study provides a method to predict the secretability and a tool to rescue the secretion by correcting the secretion-blocking regions, making a significant step in understanding the physiological properties of ABC transporter-dependent protein secretion and laying the foundation for the development of a secretion-based protein-producing platform. 相似文献
167.
Michael G. Morash Kelly H. Soanes John C. Achenbach Lee D. Ellis 《International journal of molecular sciences》2022,23(14)
Catechol is a ubiquitous chemical used in the manufacturing of fragrances, pharmaceuticals and flavorants. Environmental exposure occurs in a variety of ways through industrial processes, during pyrolysis and in effluent, yet despite its prevalence, there is limited information regarding its toxicity. While the genotoxicity and gastric carcinogenicity of catechol have been described in depth, toxicological studies have potentially overlooked a number of other effects relevant to humans. Here, we have made use of a general and behavioral larval zebrafish toxicity assay to describe previously unknown catechol-based toxicological phenomena. Behavioral testing revealed catechol-induced hypoactivity at concentrations an order of magnitude lower than observable endpoints. Catechol exposure also resulted in punctate melanocytes with concomitant decreases in the expression of pigment production and regulation markers mitfa, mc1r and tyr. Because catechol is converted into a number of toxic metabolites by tyrosinase, an enzyme found almost exclusively in melanocytes, an evaluation of the effects of catechol on these cells is critical to evaluating the safety of this chemical. This work provides insights into the toxic nature of catechol and highlights the benefits of the zebrafish larval testing platform in being able to dissect multiple aspects of toxicity with one model. 相似文献
168.
Dominik Saul Luísa Leite Barros Alexander Q. Wixom Benjamin Gellhaus Hunter R. Gibbons William A. Faubion Robyn Laura Kosinsky 《International journal of molecular sciences》2022,23(6)
Based on the rapid increase in incidence of inflammatory bowel disease (IBD), the identification of susceptibility genes and cell populations contributing to this condition is essential. Previous studies suggested multiple genes associated with the susceptibility of IBD; however, due to the analysis of whole-tissue samples, the contribution of individual cell populations remains widely unresolved. Single-cell RNA sequencing (scRNA-seq) provides the opportunity to identify underlying cellular populations. We determined the enrichment of Crohn’s disease (CD)-induced genes in a publicly available Crohn’s disease scRNA-seq dataset and detected the strongest induction of these genes in innate lymphoid cells (ILC1), highly activated T cells and dendritic cells, pericytes and activated fibroblasts, as well as epithelial cells. Notably, these genes were highly enriched in IBD-associated neoplasia, as well as sporadic colorectal cancer (CRC). Indeed, the same six cell populations displayed an upregulation of CD-induced genes in a CRC scRNA-seq dataset. Finally, after integrating and harmonizing the CD and CRC scRNA-seq data, we demonstrated that these six cell types display a gradual increase in gene expression levels from a healthy state to an inflammatory and tumorous state. Together, we identified cell populations that specifically upregulate CD-induced genes in CD and CRC patients and could, therefore, contribute to inflammation-associated tumor development. 相似文献
169.
170.
Honghui Guan Xiaojing Chen Kailiang Wang Xuyang Liu Dengfeng Zhang Yongxiang Li Yanchun Song Yunsu Shi Tianyu Wang Chunhui Li Yu Li 《International journal of molecular sciences》2022,23(5)
Tassel branch number (TBN) is one of the important agronomic traits that contribute to the efficiency of seed production and has been selected strongly during the modern maize breeding process. However, the genetic mechanisms of TBN in maize are not entirely clear. In this study, we used a B73 × CML247 recombination inbred lines (RILs) population to detect quantitative trait loci (QTLs) for TBN. A total of four QTLs (qTBN2a, qTBN2b, qTBN4, and qTBN6) and six candidate genes were identified through expression analysis. Further, one of the candidates (GRMZM2G010011, ZmPAT7) encoding an S-acyltransferase was selected to validate its function by CRISPR-Cas9 technology, and its loss-of-function lines showed a significant increase in TBN. A key SNP(−101) variation in the promoter of ZmPAT7 was significantly associated with TBN. A total of 17 distant eQTLs associated with the expression of ZmPAT7 were identified in expression quantitative trait loci (eQTL) analysis, and ZmNAC3 may be a major factor involved in regulating ZmPAT7. These findings of the present study promote our understanding of the genetic basis of tassel architecture and provide new gene resources for maize breeding improvement. 相似文献