全文获取类型
收费全文 | 10508篇 |
免费 | 192篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 56篇 |
综合类 | 6篇 |
化学工业 | 897篇 |
金属工艺 | 115篇 |
机械仪表 | 75篇 |
建筑科学 | 177篇 |
矿业工程 | 6篇 |
能源动力 | 90篇 |
轻工业 | 537篇 |
水利工程 | 31篇 |
石油天然气 | 6篇 |
武器工业 | 1篇 |
无线电 | 364篇 |
一般工业技术 | 890篇 |
冶金工业 | 6951篇 |
原子能技术 | 58篇 |
自动化技术 | 442篇 |
出版年
2021年 | 57篇 |
2020年 | 50篇 |
2019年 | 51篇 |
2018年 | 77篇 |
2017年 | 79篇 |
2016年 | 102篇 |
2015年 | 101篇 |
2014年 | 117篇 |
2013年 | 165篇 |
2012年 | 161篇 |
2011年 | 193篇 |
2010年 | 186篇 |
2009年 | 147篇 |
2008年 | 181篇 |
2007年 | 151篇 |
2006年 | 160篇 |
2005年 | 111篇 |
2004年 | 111篇 |
2003年 | 126篇 |
2002年 | 72篇 |
2001年 | 80篇 |
2000年 | 78篇 |
1999年 | 288篇 |
1998年 | 2249篇 |
1997年 | 1339篇 |
1996年 | 870篇 |
1995年 | 472篇 |
1994年 | 360篇 |
1993年 | 448篇 |
1992年 | 98篇 |
1991年 | 88篇 |
1990年 | 115篇 |
1989年 | 96篇 |
1988年 | 69篇 |
1987年 | 79篇 |
1986年 | 82篇 |
1985年 | 76篇 |
1984年 | 36篇 |
1983年 | 49篇 |
1982年 | 64篇 |
1981年 | 76篇 |
1980年 | 89篇 |
1979年 | 47篇 |
1978年 | 52篇 |
1977年 | 204篇 |
1976年 | 385篇 |
1975年 | 46篇 |
1972年 | 26篇 |
1970年 | 24篇 |
1966年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Alejandro M. Alcaraz Johanna Eva Maria Schmidt Paolo Colombo Carlos Martinez 《Journal of the European Ceramic Society》2021,41(6):3314-3320
Stop flow lithography (SFL) combines aspects of microfluidic and photolithography to continuously fabricate particles with uniform planar shapes as dictated by a mask. In this work we aim to expand the palette of materials suitable for SFL processing by investigating the use of UV-crosslinkable preceramic polymers to make ceramic particles. A commercially available methacrylated-polysiloxane was used as the preceramic polymer and was mixed with 2.5 wt% Irgacure 651 photoinitiator. A simple SFL system was assembled to continuously fabricate UV-crosslinked preceramic polymer particles in the shape of hexagons, triangles, and gears with diameters ranging from 100 to 200 μm and thicknesses of 74 μm +/- 4 μm. Particles were harvested from the excess preceramic solution, cleaned and then pyrolyzed at 1000 °C to transform them into silicon oxycarbide ceramic particles. Particle shape was maintained during pyrolysis despite a ~80 % linear shrinkage due to the removal of acryl and methyl side groups, as confirmed via FTIR. After pyrolysis the outer diameters of the SiOC particles ranged from 20 to 40 μm with thicknesses of 10 μm–12 μm. Pyrolyzed particles were successfully recovered and dispersed in water. This work demonstrates a robust path for the fabrication of ceramic particles with specific shapes from preceramic polymers via SFL. 相似文献
3.
Marcel Schmidt Dr. Yen-Hua Huang Dr. Eduardo F. Texeira de Oliveira Dr. Ana Toplak Dr. Hein J. Wijma Prof. Dr. Dick B. Janssen Prof. Dr. Jan H. van Maarseveen Prof. Dr. David J. Craik Dr. Timo Nuijens 《Chembiochem : a European journal of chemical biology》2019,20(12):1524-1529
Disulfide-rich macrocyclic peptides—cyclotides, for example—represent a promising class of molecules with potential therapeutic use. Despite their potential their efficient synthesis at large scale still represents a major challenge. Here we report new chemoenzymatic strategies using peptide ligase variants—inter alia, omniligase-1—for the efficient and scalable one-pot cyclization and folding of the native cyclotides MCoTI-II, kalata B1 and variants thereof, as well as of the θ-defensin RTD-1. The synthesis of the kB1 variant T20K was successfully demonstrated at multi-gram scale. The existence of several ligation sites for each macrocycle makes this approach highly flexible and facilitates both the larger-scale manufacture and the engineering of bioactive, grafted cyclotide variants, therefore clearly offering a valuable and powerful extension of the existing toolbox of enzymes for peptide head-to-tail cyclization. 相似文献
4.
Francesco Paolo Fiorentino Irene Marchesi Christoph Schrder Ronny Schmidt Jun Yokota Luigi Bagella 《International journal of molecular sciences》2020,21(24)
Small cell lung cancer (SCLC) is an aggressive type of lung cancer with high mortality that is caused by frequent relapses and acquired resistance. Despite that several target-based approaches with potential therapeutic impact on SCLC have been identified, numerous targeted drugs have not been successful in providing improvements in cancer patients when used as single agents. A combination of targeted therapies could be a strategy to induce maximum lethal effects on cancer cells. As a starting point in the development of new drug combination strategies for the treatment of SCLC, we performed a mid-throughput screening assay by treating a panel of SCLC cell lines with BETi or AKi in combination with PARPi or EZH2i. We observed drug synergy between I-BET762 and Talazoparib, BETi and PARPi, respectively, in SCLC cells. Combinatorial efficacy was observed in MYCs-amplified and MYCs-wt SCLC cells over SCLC cells with impaired MYC signaling pathway or non-tumor cells. We indicate that drug synergy between I-BET762 and Talazoparib is associated with the attenuation HR-DSBR process and the downregulation of various players of DNA damage response by BET inhibition, such as CHEK2, PTEN, NBN, and FANCC. Our results provide a rationale for the development of new combinatorial strategies for the treatment of SCLC. 相似文献
5.
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
6.
7.
8.
9.
10.