全文获取类型
收费全文 | 30782篇 |
免费 | 1673篇 |
国内免费 | 129篇 |
专业分类
电工技术 | 515篇 |
综合类 | 244篇 |
化学工业 | 5479篇 |
金属工艺 | 829篇 |
机械仪表 | 672篇 |
建筑科学 | 892篇 |
矿业工程 | 157篇 |
能源动力 | 530篇 |
轻工业 | 4063篇 |
水利工程 | 227篇 |
石油天然气 | 139篇 |
武器工业 | 10篇 |
无线电 | 1656篇 |
一般工业技术 | 5684篇 |
冶金工业 | 7453篇 |
原子能技术 | 173篇 |
自动化技术 | 3861篇 |
出版年
2023年 | 342篇 |
2022年 | 352篇 |
2021年 | 732篇 |
2020年 | 586篇 |
2019年 | 513篇 |
2018年 | 968篇 |
2017年 | 873篇 |
2016年 | 974篇 |
2015年 | 867篇 |
2014年 | 1001篇 |
2013年 | 1867篇 |
2012年 | 1460篇 |
2011年 | 1473篇 |
2010年 | 1222篇 |
2009年 | 1171篇 |
2008年 | 1296篇 |
2007年 | 1238篇 |
2006年 | 865篇 |
2005年 | 716篇 |
2004年 | 529篇 |
2003年 | 491篇 |
2002年 | 463篇 |
2001年 | 366篇 |
2000年 | 355篇 |
1999年 | 470篇 |
1998年 | 2323篇 |
1997年 | 1418篇 |
1996年 | 983篇 |
1995年 | 600篇 |
1994年 | 486篇 |
1993年 | 441篇 |
1992年 | 184篇 |
1991年 | 184篇 |
1990年 | 158篇 |
1989年 | 165篇 |
1988年 | 149篇 |
1987年 | 162篇 |
1986年 | 144篇 |
1985年 | 221篇 |
1984年 | 190篇 |
1983年 | 174篇 |
1982年 | 132篇 |
1981年 | 180篇 |
1980年 | 176篇 |
1979年 | 122篇 |
1978年 | 106篇 |
1977年 | 217篇 |
1976年 | 488篇 |
1975年 | 89篇 |
1973年 | 114篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Bengü Ergüden 《Yeast (Chichester, England)》2019,36(2):99-105
The correct separation of chromosomes during mitosis is necessary to prevent genetic instability and aneuploidy, which are responsible for cancer and other diseases, and it depends on proper centrosome duplication. In a recent study, we found that Smy2 can suppress the essential role of Mps2 in the insertion of yeast centrosome into the nuclear membrane by interacting with Eap1, Scp160, and Asc1 and designated this network as SESA (S my2, E ap1, S cp160, A sc1). Detailed analysis showed that the SESA network is part of a mechanism which regulates translation of POM34 mRNA. Thus, SESA is a system that suppresses spindle pole body duplication defects by repressing the translation of POM34 mRNA. In this study, we performed a genome-wide screening in order to identify new members of the SESA network and confirmed Dhh1 as a putative member. Dhh1 is a cytoplasmic DEAD-box helicase known to regulate translation. Therefore, we hypothesized that Dhh1 is responsible for the highly selective inhibition of POM34 mRNA by SESA. 相似文献
42.
43.
Freddy A. Bernal Dr. Marcel Kaiser Prof. Dr. Bernhard Wünsch Prof. Dr. Thomas J. Schmidt 《ChemMedChem》2020,15(1):68-78
Protozoal infections are still a global health problem, threatening the lives of millions of people around the world, mainly in impoverished tropical and sub-tropical regions. Thus, in view of the lack of efficient therapies and increasing resistances against existing drugs, this study describes the antiprotozoal potential of synthetic cinnamate ester analogues and their structure-activity relationships. In general, Leishmania donovani and Trypanosoma brucei were quite susceptible to the compounds in a structure-dependent manner. Detailed analysis revealed a key role of the substitution pattern on the aromatic ring and a marked effect of the side chain on the activity against these two parasites. The high antileishmanial potency and remarkable selectivity of the nitro-aromatic derivatives suggested them as promising candidates for further studies. On the other hand, the high in vitro potency of catechol-type compounds against T. brucei could not be extrapolated to an in vivo mouse model. 相似文献
44.
Alice Maurer Prof. Dr. Florian P. Seebeck 《Chembiochem : a European journal of chemical biology》2020,21(20):2908-2911
Ergothioneine has emerged as a crucial cytoprotectant in the pathogenic lifestyle of Mycobacterium tuberculosis. Production of this antioxidant from primary metabolites may be regulated by phosphorylation of Thr213 in the active site of the methyltransferase EgtD. The structure of mycobacterial EgtD suggests that this post-translational modification would require a large-scale change in conformation to make the active-site residue accessible to a protein kinase. In this report, we show that, under in vitro conditions, EgtD is not a substrate of protein kinase PknD. 相似文献
45.
Abdeljaoued Emna Brulé Mathieu Tayibi Saida Manolakos Dimitris Oukarroum Abdallah Monlau Florian Barakat Abdellatif 《Clean Technologies and Environmental Policy》2020,22(10):1967-1997
Clean Technologies and Environmental Policy - Biochar has caught great attention over the last decade, yielding a large number of publications in a broad range of disciplines. This scientometric... 相似文献
46.
47.
Özge Seçmeler Özlem Güçlü Üstündağ 《International Journal of Food Science & Technology》2019,54(5):1609-1616
The partitioning of predominant lipophilic olive bioactives (squalene, β-sitosterol and α-tocopherol) in olive oil processing was studied for the first time using common integrated olive milling plant. 7% of the oil and 5% of the squalene present in the olives was lost in the last pomace. β-sitosterol and α-tocopherol, which are mainly concentrated in the seed of the olive fruit, was recovered in virgin olive oil to a lesser extent (66%, 67%) while 10% were lost in last pomace. Thus, the loss of β-sitosterol and α-tocopherol was higher than that of squalene and oil, due to nonrecovered bound forms. 19% of the α-tocopherol and 21% of the β-sitosterol loss was unaccounted for, which can be attributed to degradation of α-tocopherol and incomplete recovery of sterols from the olive and pomace matrices. This study provides a basis for process development studies. 相似文献
48.
H Daims F Maixner S Lücker K Stoecker K Hace M Wagner 《Water science and technology》2006,54(1):21-27
Nitrite-oxidizing bacteria of the genus Nitrospira are key nitrifiers in wastewater treatment plants. Pure cultures of these organisms are unavailable, but cultivation-independent molecular methods make it possible to detect Nitrospira-like bacteria in environmental samples and to investigate their ecophysiology. Comprehensive screening of natural and engineered habitats and of public databases for 16S rRNA sequences of Nitrospira-like bacteria revealed a surprisingly high biodiversity in the genus Nitrospira, which comprises at least four phylogenetic sublineages. All Nitrospira-like bacteria detected in wastewater treatment plants belonged to the sublineages I and II. Subsequently, the population dynamics of different Nitrospira-like bacteria were monitored, by quantitative fluorescence in situ hybridization with rRNA-targeted probes, confocal laser scanning microscopy and digital image analysis, during incubation of nitrifying activated sludge in media containing different nitrite concentrations. These experiments showed that Nitrospira-like bacteria, which were affiliated with the phylogenetic sublineages I or II of the genus Nitrospira, responded differently to nitrite concentration shifts. Previously unknown properties of Nitrospira-like bacteria were discovered in the course of an environmental genomics project. Implications of the obtained results for fundamental understanding of the microbial ecology of nitrite oxidizers as well as for future improvement of nutrient removal in wastewater treatment plants are discussed. 相似文献
49.
50.
S. Büttgenbach J. Hesselbach R. Tutsch M. Berndt B. Hoxhold K. Schöttler 《Microsystem Technologies》2006,12(7):665-669
Positioning accuracies in the range of a few micrometers and below are necessary for the assembly of active micro-systems. In order to reach these accuracies, an assembly system for sensor guided micro-assembly is developed in the Collaborative Research Centre 516 “Design and manufacturing of active micro-systems”. The combination of a parallel robot with an integrated 3D vision sensor and a micro-gripper enables to reach relative positioning accuracies below 1 μm. 相似文献