全文获取类型
收费全文 | 389392篇 |
免费 | 6164篇 |
国内免费 | 1252篇 |
专业分类
电工技术 | 6125篇 |
综合类 | 2563篇 |
化学工业 | 61415篇 |
金属工艺 | 17141篇 |
机械仪表 | 12143篇 |
建筑科学 | 10003篇 |
矿业工程 | 2510篇 |
能源动力 | 8379篇 |
轻工业 | 32233篇 |
水利工程 | 4561篇 |
石油天然气 | 7509篇 |
武器工业 | 21篇 |
无线电 | 41764篇 |
一般工业技术 | 77828篇 |
冶金工业 | 54852篇 |
原子能技术 | 7946篇 |
自动化技术 | 49815篇 |
出版年
2021年 | 2705篇 |
2019年 | 2428篇 |
2018年 | 18353篇 |
2017年 | 17269篇 |
2016年 | 14464篇 |
2015年 | 3802篇 |
2014年 | 5547篇 |
2013年 | 14179篇 |
2012年 | 10993篇 |
2011年 | 19569篇 |
2010年 | 16537篇 |
2009年 | 14989篇 |
2008年 | 16474篇 |
2007年 | 17225篇 |
2006年 | 8757篇 |
2005年 | 9088篇 |
2004年 | 8413篇 |
2003年 | 8184篇 |
2002年 | 7708篇 |
2001年 | 7025篇 |
2000年 | 6728篇 |
1999年 | 6568篇 |
1998年 | 15135篇 |
1997年 | 11403篇 |
1996年 | 8878篇 |
1995年 | 6768篇 |
1994年 | 6122篇 |
1993年 | 5983篇 |
1992年 | 4638篇 |
1991年 | 4592篇 |
1990年 | 4378篇 |
1989年 | 4389篇 |
1988年 | 4346篇 |
1987年 | 3690篇 |
1986年 | 3674篇 |
1985年 | 4333篇 |
1984年 | 4119篇 |
1983年 | 3739篇 |
1982年 | 3554篇 |
1981年 | 3702篇 |
1980年 | 3537篇 |
1979年 | 3461篇 |
1978年 | 3539篇 |
1977年 | 4049篇 |
1976年 | 5181篇 |
1975年 | 3257篇 |
1974年 | 3081篇 |
1973年 | 3106篇 |
1972年 | 2687篇 |
1971年 | 2514篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Multimedia Tools and Applications - Remote Sensing categorical signature classification has gained significant implications on spatial resolution image analysis due to differences in the... 相似文献
3.
Chumakov Yu. A. Knyazeva A. G. Pribytkov G. A. 《Theoretical Foundations of Chemical Engineering》2021,55(3):490-503
Theoretical Foundations of Chemical Engineering - On the basis of the classic concepts of the theory of solid-phase combustion, for the first time, a model with a detailed scheme of chemical... 相似文献
4.
Leibetseder Andreas Schoeffmann Klaus Keckstein Jörg Keckstein Simon 《Multimedia Tools and Applications》2022,81(5):6191-6215
Multimedia Tools and Applications - Endometriosis is a common gynecologic condition typically treated via laparoscopic surgery. Its visual versatility makes it hard to identify for non-specialized... 相似文献
5.
6.
Engineering new glass compositions have experienced a sturdy tendency to move forward from (educated) trial-and-error to data- and simulation-driven strategies. In this work, we developed a computer program that combines data-driven predictive models (in this case, neural networks) with a genetic algorithm to design glass compositions with desired combinations of properties. First, we induced predictive models for the glass transition temperature (Tg) using a dataset of 45,302 compositions with 39 different chemical elements, and for the refractive index (nd) using a dataset of 41,225 compositions with 38 different chemical elements. Then, we searched for relevant glass compositions using a genetic algorithm informed by a design trend of glasses having high nd (1.7 or more) and low Tg (500 °C or less). Two candidate compositions suggested by the combined algorithms were selected and produced in the laboratory. These compositions are significantly different from those in the datasets used to induce the predictive models, showing that the used method is indeed capable of exploration. Both glasses met the constraints of the work, which supports the proposed framework. Therefore, this new tool can be immediately used for accelerating the design of new glasses. These results are a stepping stone in the pathway of machine learning-guided design of novel glasses. 相似文献
7.
Journal of Chemical Ecology - Biocontrol agents such as parasitic wasps use long-range volatiles and host-associated cues from lower trophic levels to find their hosts. However, this chemical... 相似文献
8.
Prof. Andrea Baier Dr. Anne Kokel Dr. William Horton Ewa Gizińska Dr. Garima Pandey Prof. Ryszard Szyszka Prof. Béla Török Prof. Marianna Török 《ChemMedChem》2021,16(12):1927-1932
A set of novel hydrazone derivatives were synthesized and analyzed for their biological activities. The compounds were tested for their inhibitory effect on the phosphorylating activity of the protein kinase CK2, and their antioxidant activity was also determined in three commonly used assays. The hydrazones were evaluated for their radical scavenging against the DPPH, ABTS and peroxyl radicals. Several compounds have been identified as good antioxidants as well as potent protein kinase CK2 inhibitors. Most hydrazones containing a 4-N(CH3)2 residue or perfluorinated phenyl rings showed high activity in the radical-scavenging assays and possess nanomolar IC50 values in the kinase assays. 相似文献
9.
Journal of Communications Technology and Electronics - A statistical study of the effectiveness of the non-threshold search procedure for a noise-like phase-shift keyed signal by the delay time is... 相似文献
10.
Marcus Reppich Zdeněk Jegla Jakob Grondinger Yaovi Ouézou Azouma Vojtěch Turek 《化学,工程师,技术》2021,93(10):1581-1589
This study investigates the behavior of fruit and vegetable samples during drying. The experimental data are fitted to several different thin-layer drying models. Regression analysis is used to determine model parameters, while statistical indicators serve to evaluate the goodness of fit. The power function model gives the best fit for all examined samples. Based on this model, different drying and heat storage technologies can be combined to ensure that the required residual moisture content of an agricultural product is reached. It is demonstrated on the case of a specific Togolese processing plant that under favorable conditions, fossil fuel consumption can be decreased by 33 %. 相似文献