首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6166篇
  免费   567篇
  国内免费   3篇
电工技术   65篇
综合类   1篇
化学工业   1572篇
金属工艺   166篇
机械仪表   180篇
建筑科学   252篇
矿业工程   22篇
能源动力   241篇
轻工业   951篇
水利工程   43篇
石油天然气   52篇
无线电   491篇
一般工业技术   1447篇
冶金工业   103篇
原子能技术   33篇
自动化技术   1117篇
  2024年   32篇
  2023年   89篇
  2022年   111篇
  2021年   230篇
  2020年   232篇
  2019年   187篇
  2018年   349篇
  2017年   372篇
  2016年   422篇
  2015年   240篇
  2014年   323篇
  2013年   711篇
  2012年   360篇
  2011年   426篇
  2010年   359篇
  2009年   339篇
  2008年   309篇
  2007年   293篇
  2006年   191篇
  2005年   146篇
  2004年   134篇
  2003年   114篇
  2002年   123篇
  2001年   53篇
  2000年   56篇
  1999年   44篇
  1998年   41篇
  1997年   40篇
  1996年   43篇
  1995年   32篇
  1994年   25篇
  1993年   24篇
  1992年   15篇
  1991年   20篇
  1990年   10篇
  1989年   16篇
  1988年   13篇
  1986年   8篇
  1985年   23篇
  1984年   11篇
  1983年   11篇
  1982年   21篇
  1981年   14篇
  1980年   12篇
  1979年   14篇
  1978年   11篇
  1977年   8篇
  1975年   8篇
  1974年   11篇
  1973年   8篇
排序方式: 共有6736条查询结果,搜索用时 281 毫秒
1.
2.
Multimedia Tools and Applications - Recently, many concepts in technology has been changed. According to the digital transformation trends, Internet of Things (IoT) represents an interested...  相似文献   
3.
Journal of Low Temperature Physics - This study modeled and investigated the magnetocaloric effect in Ni2MnGa Heusler alloy characterized by its magnetic entropy change (ΔSm) and its...  相似文献   
4.
We aimed to compare detailed fat distribution and lipid profile between young adults with congenital adrenal hyperplasia due to 21-hydroxylase enzyme deficiency and a control group. We also verified independent associations of treatment duration and daily hydrocortisone dose equivalent (HDE) with lipid profile within patients. This case–control study included 23 patients (7 male and 16 female) matched by an age range of young adults (18–31 years) with 20 control subjects (8 male and 12 female). Dual energy X-ray absorptiometry was used to measure the fat distribution. Male patients demonstrated elevated indices of fat mass for total (7.7 ± 2.1 vs. 4.5 ± 1.3 kg/m2, p = 0.003), trunk (4.0 ± 1.2 vs. 2.2 ± 0.8 kg/m2, p = 0.005), android (0.63 ± 0.24 vs. 0.32 ± 0.15 kg/m2, p = 0.008), gynoid (1.34 ± 0.43 vs. 0.74 ± 0.24 kg/m2, p = 0.005), arm (0.65 ± 0.16 vs. 0.39 ± 0.10 kg/m2, p = 0.009), and leg regions (2.7 ± 0.8 vs. 1.6 ± 0.4 kg/m2, p = 0.005) than the control group, but not in females. However, female patients demonstrated elevated ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (1.90 ± 0.46 vs. 1.39 ± 0.47, p = 0.009) than the control group, but not in males. Total fat mass was inversely correlated with total testosterone (r = −0.64, p = 0.014) and positively correlated with leptin in males (r = 0.75, p = 0.002). An elevated daily HDE (β = 0.43, p = 0.038 and β = 0.47, p = 0.033) and trunk to total fat mass ratio (β = 0.46, p = 0.025, and β = 0.45, p = 0.037) were independently correlated with impaired lipid profile markers. Although there is no altered lipid profile, male patients demonstrated an increased fat distribution. However, female patients presented with an impaired lipid profile marker but demonstrated close values of normal fat distribution. Interestingly, the dose of glucocorticoid therapy can have some role in the lipid mechanisms.  相似文献   
5.
In this paper, we extend the Bonferroni mean (BM) operator with the picture fuzzy numbers (PFNs) to propose novel picture fuzzy aggregation operators and demonstrate their application to multicriteria decision making (MCDM). On the basis of the algebraic operational rules of PFNs and BM, we introduce some aggregation operators: the picture fuzzy Bonferroni mean, the picture fuzzy normalized weighted Bonferroni mean, and the picture fuzzy ordered weighted Bonferroni mean. Then, a new picture fuzzy MCDM method is proposed with the help of the proposed operators. Lastly, a practical application of proposed model is given to verify the developed model and related results of the proposed model is compared with the results of the existing models to indicate its applicability.  相似文献   
6.
7.
8.
9.
10.
In the quest for new antibacterial agents, a series of novel long- and medium-chain mono- and disubstituted β-lactones was developed. Their activity against three pathogenic mycobacteria—M. abscessus, M. marinum, and M. tuberculosis—was assessed by the resazurin microtiter assay (REMA). Among the 16 β-lactones synthesized, only 3-hexadecyloxetan-2-one (VM005) exhibited promising activity against M. abscessus, whereas most of the β-lactones showed interesting activities against M. marinum, similar to that of the classical antibiotic, isoniazid. Regarding M. tuberculosis, six compounds were found to be active against this mycobacterium, with β-lactone VM008 [trans-(Z)-3-(hexadec-7-en-1-yl)-4-propyloxetan-2-one] being the best growth inhibitor. The promising antibacterial activities of the best compounds in this series suggest that these molecules may serve as leads for the development of much more efficient antimycobacterial agents.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号