全文获取类型
收费全文 | 5821篇 |
免费 | 538篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 62篇 |
综合类 | 1篇 |
化学工业 | 1486篇 |
金属工艺 | 151篇 |
机械仪表 | 169篇 |
建筑科学 | 249篇 |
矿业工程 | 22篇 |
能源动力 | 200篇 |
轻工业 | 884篇 |
水利工程 | 37篇 |
石油天然气 | 39篇 |
无线电 | 462篇 |
一般工业技术 | 1416篇 |
冶金工业 | 104篇 |
原子能技术 | 30篇 |
自动化技术 | 1051篇 |
出版年
2024年 | 32篇 |
2023年 | 70篇 |
2022年 | 83篇 |
2021年 | 197篇 |
2020年 | 204篇 |
2019年 | 167篇 |
2018年 | 313篇 |
2017年 | 337篇 |
2016年 | 397篇 |
2015年 | 236篇 |
2014年 | 307篇 |
2013年 | 685篇 |
2012年 | 346篇 |
2011年 | 433篇 |
2010年 | 334篇 |
2009年 | 316篇 |
2008年 | 300篇 |
2007年 | 288篇 |
2006年 | 193篇 |
2005年 | 146篇 |
2004年 | 133篇 |
2003年 | 112篇 |
2002年 | 121篇 |
2001年 | 48篇 |
2000年 | 57篇 |
1999年 | 39篇 |
1998年 | 42篇 |
1997年 | 36篇 |
1996年 | 41篇 |
1995年 | 32篇 |
1994年 | 25篇 |
1993年 | 21篇 |
1992年 | 15篇 |
1991年 | 20篇 |
1990年 | 8篇 |
1989年 | 14篇 |
1988年 | 12篇 |
1986年 | 8篇 |
1985年 | 23篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 8篇 |
1975年 | 7篇 |
1974年 | 10篇 |
1973年 | 8篇 |
排序方式: 共有6363条查询结果,搜索用时 15 毫秒
1.
Deniz Caylioglu Rieke Johanna Meyer Dana Hellmold Carolin Kubelt Michael Synowitz Janka Held-Feindt 《International journal of molecular sciences》2021,22(7)
Glioblastoma (GBM) is a barely treatable disease due to its profound chemoresistance. A distinct inter- and intratumoral heterogeneity reflected by specialized microenvironmental niches and different tumor cell subpopulations allows GBMs to evade therapy regimens. Thus, there is an urgent need to develop alternative treatment strategies. A promising candidate for the treatment of GBMs is AT101, the R(-) enantiomer of gossypol. The present study evaluates the effects of AT101, alone or in combination with temozolomide (TMZ), in a microenvironmental glioma stem cell niche model of two GBM cell lines (U251MG and U87MG). AT101 was found to induce strong cytotoxic effects on U251MG and U87MG stem-like cells in comparison to the respective native cells. Moreover, a higher sensitivity against treatment with AT101 was observed upon incubation of native cells with a stem-like cell-conditioned medium. This higher sensitivity was reflected by a specific inhibitory influence on the p-p42/44 signaling pathway. Further, the expression of CXCR7 and the interleukin-6 receptor was significantly regulated upon these stimulatory conditions. Since tumor stem-like cells are known to mediate the development of tumor recurrences and were observed to strongly respond to the AT101 treatment, this might represent a promising approach to prevent the development of GBM recurrences. 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.
5.
6.
7.
8.
Thin Film Thermoelectric Metal–Organic Framework with High Seebeck Coefficient and Low Thermal Conductivity 下载免费PDF全文
9.
Pierre Santucci Christina Dedaki Alexandros Athanasoulis Laura Gallorini Anaïs Munoz Dr. Stéphane Canaan Dr. Jean-François Cavalier Dr. Victoria Magrioti 《ChemMedChem》2019,14(3):349-358
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
10.
Gabriel Rodrigues de Almeida Neto Cesar Augusto Gonçalves Beatrice Daniel Rodrigo Leiva Luiz Antonio Pessan 《International Journal of Hydrogen Energy》2021,46(46):23767-23778
This study investigates the preparation of polyetherimide (PEI) – LaNi5 composites films for hydrogen storage. Prior to the polymer addition, LaNi5 was ball-milled at different conditions (250, 350, and 450 RPM) and annealed at 500 °C for 1 h under vacuum. The composites were produced with BM-LaNi5-350 (PEI/LaNi5-350) and annealed BM-LaNi5-350 (PEI/LaNi5-350-TT). Membranes were successfully produced through solvent casting assisted by an ultrasonic bath. The particles dispersion and the film morphology did not change after hydrogenation cycles. In the H2 sorption experiments at 43 °C and 20 bar, the films stored H2 without incubation time; both samples reached a capacity of ~0.6 wt%. The H2 sorption kinetics of PEI/LaNi5-350 was comparable to that of BM-LaNi5-350, whereas PEI/LaNi5-350-TT presented significantly slower kinetics. LaNi5 oxidation was hindered by PEI, showing that it can be explored to improve metal hydrides air resistance. The results demonstrated that PEI films filled with LaNi5 are promising materials for hydrogen storage. 相似文献