全文获取类型
收费全文 | 11490篇 |
免费 | 913篇 |
国内免费 | 32篇 |
专业分类
电工技术 | 134篇 |
综合类 | 5篇 |
化学工业 | 3006篇 |
金属工艺 | 357篇 |
机械仪表 | 402篇 |
建筑科学 | 365篇 |
矿业工程 | 24篇 |
能源动力 | 484篇 |
轻工业 | 1402篇 |
水利工程 | 75篇 |
石油天然气 | 70篇 |
无线电 | 1437篇 |
一般工业技术 | 2418篇 |
冶金工业 | 538篇 |
原子能技术 | 76篇 |
自动化技术 | 1642篇 |
出版年
2024年 | 39篇 |
2023年 | 110篇 |
2022年 | 184篇 |
2021年 | 409篇 |
2020年 | 355篇 |
2019年 | 315篇 |
2018年 | 530篇 |
2017年 | 551篇 |
2016年 | 615篇 |
2015年 | 414篇 |
2014年 | 553篇 |
2013年 | 1099篇 |
2012年 | 684篇 |
2011年 | 772篇 |
2010年 | 613篇 |
2009年 | 625篇 |
2008年 | 562篇 |
2007年 | 492篇 |
2006年 | 393篇 |
2005年 | 270篇 |
2004年 | 275篇 |
2003年 | 239篇 |
2002年 | 214篇 |
2001年 | 181篇 |
2000年 | 167篇 |
1999年 | 134篇 |
1998年 | 238篇 |
1997年 | 191篇 |
1996年 | 151篇 |
1995年 | 115篇 |
1994年 | 100篇 |
1993年 | 88篇 |
1992年 | 70篇 |
1991年 | 73篇 |
1990年 | 39篇 |
1989年 | 51篇 |
1988年 | 44篇 |
1987年 | 25篇 |
1986年 | 29篇 |
1985年 | 45篇 |
1984年 | 33篇 |
1983年 | 36篇 |
1982年 | 35篇 |
1981年 | 32篇 |
1980年 | 36篇 |
1979年 | 26篇 |
1977年 | 20篇 |
1976年 | 33篇 |
1974年 | 17篇 |
1973年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 781 毫秒
1.
Bokyung Kim Young Ho Ko Massimiliano Runfola Simona Rapposelli Gabriella Ortore Grazia Chiellini Jin Hae Kim 《International journal of molecular sciences》2021,22(7)
Thyromimetics, whose physicochemical characteristics are analog to thyroid hormones (THs) and their derivatives, are promising candidates as novel therapeutics for neurodegenerative and metabolic pathologies. In particular, sobetirome (GC-1), one of the initial halogen-free thyromimetics, and newly synthesized IS25 and TG68, with optimized ADME-Tox profile, have recently attracted attention owing to their superior therapeutic benefits, selectivity, and enhanced permeability. Here, we further explored the functional capabilities of these thyromimetics to inhibit transthyretin (TTR) amyloidosis. TTR is a homotetrameric transporter protein for THs, yet it is also responsible for severe amyloid fibril formation, which is facilitated by tetramer dissociation into non-native monomers. By combining nuclear magnetic resonance (NMR) spectroscopy, computational simulation, and biochemical assays, we found that GC-1 and newly designed diphenyl-methane-based thyromimetics, namely IS25 and TG68, are TTR stabilizers and efficient suppressors of TTR aggregation. Based on these observations, we propose the novel potential of thyromimetics as a multi-functional therapeutic molecule for TTR-related pathologies, including neurodegenerative diseases. 相似文献
2.
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
3.
Juliano Henrique Borges Daniel Minutti de Oliveira Sofia Helena Valente de Lemos-Marini Bruno Geloneze Ezequiel Moreira Gonçalves Gil Guerra-Júnior 《Lipids》2021,56(1):101-110
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
4.
SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
5.
6.
7.
8.
9.
10.
Mohamed A.El-Nemr Ibrahim M.A.Ismail Nabil M.Abdelmonem Ahmed El Nemr Safaa Ragab 《中国化学工程学报》2021,36(8):199-222
Watermelon peel residues were used to produce a new biochar by dehydration method. The new biochar has undergone two methods of chemical modification and the effect of this chemical modification on its ability to adsorb Cr(VI) ions from aqueous solution has been investigated. Three biochars, Melon-B, Melon-BO-NH_2 and Melon-BO-TETA, were made from watermelon peel via dehydration with 50% sulfuric acid to give Melon-B followed by oxidation with ozone and amination using ammonium hydroxide to give Melon-BO-NH_2 or Triethylenetetramine(TETA) to give Melon-BO-TETA. The prepared biochars were characterized by BET, BJH,SEM, FT-IR, TGA, DSC and EDAX analyses. The highest removal percentage of Cr(VI) ions was 69% for Melon-B,98% for Melon-BO-NH_2 and 99% for Melon-BO-TETA biochars of 100 mg·L~(-1) Cr(VI) ions initial concentration and 1.0 g·L~(-1) adsorbents dose. The unmodified biochar(Melon-B) and modified biochars(Melon-BO-NH_2 and Melon-BO-TETA) had maximum adsorption capacities(Qm) of 72.46, 123.46, and 333.33 mg·g~(-1), respectively.The amination of biochar reduced the pore size of modified biochar, whereas the surface area was enhanced.The obtained data of isotherm models were tested using different error function equations. The Freundlich,Tempkin and Langmuir isotherm models were best fitted to the experimental data of Melon-B, Melon-BO-NH_2 and Melon-BO-TETA, respectively. The adsorption rate was primarily controlled by pseudo-second–order rate model. Conclusively, the functional groups interactions are important for adsorption mechanisms and expected to control the adsorption process. The adsorption for the Melon-B, Melon-BO-NH_2 and Melon-BO-TETA could be explained for acid–base interaction and hydrogen bonding interaction. 相似文献