全文获取类型
收费全文 | 787篇 |
免费 | 30篇 |
国内免费 | 35篇 |
专业分类
化学 | 761篇 |
晶体学 | 1篇 |
力学 | 3篇 |
综合类 | 13篇 |
数学 | 1篇 |
物理学 | 73篇 |
出版年
2023年 | 17篇 |
2022年 | 123篇 |
2021年 | 91篇 |
2020年 | 44篇 |
2019年 | 32篇 |
2018年 | 32篇 |
2017年 | 20篇 |
2016年 | 31篇 |
2015年 | 32篇 |
2014年 | 26篇 |
2013年 | 23篇 |
2012年 | 33篇 |
2011年 | 35篇 |
2010年 | 22篇 |
2009年 | 33篇 |
2008年 | 31篇 |
2007年 | 37篇 |
2006年 | 29篇 |
2005年 | 22篇 |
2004年 | 26篇 |
2003年 | 22篇 |
2002年 | 11篇 |
2001年 | 16篇 |
2000年 | 10篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1981年 | 2篇 |
1979年 | 2篇 |
排序方式: 共有852条查询结果,搜索用时 15 毫秒
151.
152.
尖海龙提取物抗癌作用的研究 总被引:4,自引:0,他引:4
制备尖海龙提取物,再将其分别作用于Hela,SK-RB-3细胞系,从细胞形态变化,细胞计数,集落形成率,细胞分裂指数变化观察体外药效,结果表明,尖海龙提取物可改变肿瘤的正常生活形态,又可显著抑制肿瘤细胞的增殖,降低集落形成率,减少分裂指数,从而证实尖海龙提取物具有抗癌活性,其在癌症的治疗与预防方面具有实用价值。 相似文献
153.
Hui-Hsuan Lin Jen-Ying Hsu Chiao-Yun Tseng Xiao-Yin Huang Hsien-Chun Tseng Jing-Hsien Chen 《Molecules (Basel, Switzerland)》2022,27(13)
The aim is to investigate the effect of lotus (Nelumbo nucifera Gaertn.) seedpod extract (LSE) on acetaminophen (APAP)-induced hepatotoxicity. LSE is rich in polyphenols and has potent antioxidant capacity. APAP is a commonly used analgesic, while APAP overdose is the main reason for drug toxicity in the liver. Until now, there has been no in vitro test of LSE in drug-induced hepatotoxicity responses. LSEs were used to evaluate the effect on APAP-induced cytotoxicity, ROS level, apoptotic rate, and molecule mechanisms. The co-treatment of APAP and LSEs elevated the survival rate and decreased intracellular ROS levels on HepG2 cells. LSEs treatment could significantly reduce APAP-induced HepG2 apoptosis assessed by DAPI and Annexin V/PI. The further molecule mechanisms indicated that LSEs decreased Fas/FasL binding and reduced Bax and tBid to restore mitochondrial structure and subsequently suppress downstream apoptosis cascade activation. These declines in COX-2, NF-κB, and iNOS levels were observed in co-treatment APAP and LSEs, which indicated that LSEs could ameliorate APAP-induced inflammation. LSE protected APAP-induced apoptosis by preventing extrinsic, intrinsic, and JNK-mediated pathways. In addition, the restoration of mitochondria and inflammatory suppression in LSEs treatments indicated that LSEs could decrease oxidative stress induced by toxic APAP. Therefore, LSE could be a novel therapeutic option for an antidote against overdose of APAP. 相似文献
154.
Tian-Yang Wu Juan Liang Jing-Ya Ai Jing-Long Cui Wei-Dong Huang Yi-Lin You Ji-Cheng Zhan 《Molecules (Basel, Switzerland)》2022,27(13)
Mulberry extract has been proven to have the effect of resisting alcohol damage, but its mechanism is still unclear. In this study, the composition of mulberry ethanol extract (MBE) was identified by LC-MS/MS and the main components of MBE were ascertained by measuring. Gastric mucosal epithelial (GES-1) cells were used to elucidate the mechanism of MBE and rutin (the central part of MBE) helped protect against alcohol damage. The results revealed that phenolics accounted for the majority of MBE, accounting for 308.6 mg/g gallic acid equivalents and 108 substances were identified, including 37 flavonoids and 50 non-flavonoids. The treatment of 400 μg/mL MBE and 320 μM rutin reduced early cell apoptosis and the content of intracellular reactive oxygen species, malondialdehyde and increased glutathione. The qPCR results indicated that the MBE inhibits the expression of genes in the mitogen-activated protein kinase (MAPK) pathway, including p38, JNK, ERK and caspase-3; rutin inhibits the expression of p38 and caspase-3. Overall, MBE was able to reduce the oxidative stress of GES-1 cells and regulated apoptosis-related genes of the MAPK pathway. This study provides information for developing anti-ethanol injury drugs or functional foods. 相似文献
155.
Stefania Cometa Carla Zannella Francesco Busto Anna De Filippis Gianluigi Franci Massimiliano Galdiero Elvira De Giglio 《Molecules (Basel, Switzerland)》2022,27(13)
In the present study, a hydroxytyrosol-rich Olea europaea L. fruit extract (OFE) was added to three thoroughly green formulations—hydrogel, oleogel, and cream—in order to evaluate their antiviral activity against HSV-1. The extract was characterized by different analytical techniques, i.e., FT-IR, XPS, and TGA. HPLC analyses were carried out to monitor the content and release of hydroxytyrosol in the prepared formulations. The total polyphenol content and antioxidant activity were investigated through Folin–Ciocâlteu’s reagent, DPPH, and ABTS assays. The ability of the three formulations to convey active principles to the skin was evaluated using a Franz cell, showing that the number of permeated polyphenols in the hydrogel (272.1 ± 1.8 GAE/g) was significantly higher than those in the oleogel and cream (174 ± 10 and 179.6 ± 2 GAE/g, respectively), even if a negligible amount of hydroxytyrosol crossed the membrane for all the formulations. The cell viability assay indicated that the OFE and the three formulations were not toxic to cultured Vero cells. The antiviral activity tests highlighted that the OFE had a strong inhibitory effect against HSV-1 with a 50% inhibitory concentration (IC50) at 25 µg/mL, interfering directly with the viral particles. Among the three formulations, the hydrogel exhibited the highest antiviral activity also against the acyclovir-resistant strain. 相似文献
156.
157.
Bo-Yang Hsu Chen-Te Jen Baskaran Stephen Inbaraj Bing-Huei Chen 《Molecules (Basel, Switzerland)》2022,27(10)
Ginseng (Panax quinquefolius), a popular herbal and nutritional supplement consumed worldwide, has been demonstrated to possess vital biological activities, which can be attributed to the presence of ginsenosides. However, the presence of ginsenosides in ginseng root residue, a by-product obtained during processing of ginseng beverage, remains unexplored. The objectives of this study were to develop a high-performance liquid chromatography-photodiode array detection-mass spectrometry (HPLC-DAD-ESI-MS) and an ultra-high-performance-liquid-chromatography-tandem mass spectrometry (UPLC-HRMS-MS/MS) method for the comparison of ginsenoside analysis in ginseng root residue. Results showed that by employing a Supelco Ascentis Express C18 column (150 × 4.6 mm ID, particle size 2.7 μm) and a gradient mobile phase of deionized water and acetonitrile with a flow rate at 1 mL/min and detection at 205 nm, a total of 10 ginsenosides, including internal standard saikosaponin A, were separated within 18 min and detected by HPLC-DAD-ESI-MS. Whereas with UPLC-HRMS-MS/MS, all the 10 ginsenosides were separated within six minutes by using an Acquity UPLC BEH C18 column (50 × 2.1 mm ID, particle size 1.7 μm, 130 Å) and a gradient mobile phase of ammonium acetate and acetonitrile with column temperature at 50 °C, flow rate at 0.4 mL/min and detection by selected reaction monitoring (SRM) mode. High accuracy and precision was shown, with limit of quantitation (LOQ) ranging from 0.2–1.9 μg/g for HPLC-DAD-ESI-MS and 0.269–6.640 ng/g for UPLC-HRMS-MS/MS. The contents of nine ginsenosides in the ginseng root residue ranged from <LOQ-26.39 mg/g by HPLC-DAD-ESI-MS and <LOQ-21.25 mg/g by UPLC-HRMS-MS/MS, with a total amount of 38.37 and 34.71 mg/g, respectively. 相似文献
158.
Hae-Lim Kim Sung-Kwon Lee Da-Eun Min Bong-Keun Choi Dong-Ryung Lee 《Molecules (Basel, Switzerland)》2022,27(10)
Dyglomera® is an aqueous ethanol extract of the fruit pods of Dichrostachys glomerata, a Cameroonian spice. Several studies have shown its anti-diabetic and anti-obesity effects. However, the underlying mechanisms for such effects remain unclear. Thus, the objective of this study was to investigate the anti-obesity effect of Dyglomera® and its underlying mechanisms in mice with high-fat diet-induced obesity and 3T3-L1 adipocytes. Our results revealed that Dyglomera® inhibited adipogenesis and lipogenesis by regulating AMPK phosphorylation in white adipose tissues (WATs) and 3T3-L1 adipocytes and promoted lipolysis by increasing the expression of lipolysis-related proteins. These results suggest that Dyglomera® can be used as an effective dietary supplement for treating obesity due to its modulating effect on adipogenesis/lipogenesis and lipolysis. 相似文献
159.
Rosa I. Ventura-Aguilar Csar Gnzalez-Andrade Mnica Hernndez-Lpez Zormy N. Correa-Pacheco Pervin K. Teksür Margarita de L. Ramos-García Silvia Bautista-Baos 《Molecules (Basel, Switzerland)》2022,27(14)
The fungus Aspergillus flavus causes serious damage to maize grains and its by-products, such as tortilla. Currently, animal and plant derivatives, such as chitosan and propolis, and plant extract residues, respectively, are employed as alternatives of synthetic fungicides. The objective of this research was to evaluate the efficacy of several formulations based on propolis-chitosan-pine resin extract on the in vitro growth of A. flavus, the growth of maize grain plantlets and the quality of stored tortillas at 4 and 28 °C. The most outstanding formulation was that based on 59.7% chitosan + 20% propolis nanoparticles + 20% pine resin extract nanoparticles; since the in vitro conidia germination of A. flavus did not occur, disease incidence on grains was 25–30% and in tortillas, 0% infection was recorded, along with low aflatoxin production (1.0 ppb). The grain germination and seedling growth were markedly reduced by the nanocoating application. The percentage weight loss and color of tortillas were more affected by this coating compared to the control, and the rollability fell within the scale of non-ruptured at 4 °C and partially ruptured at 28 °C. The next step is to evaluate the toxicity of this formulation. 相似文献
160.
为研究秦巴山区钮子根茎、叶中微量元素的含量,采用微波消解的方法处理样品,用火焰原子吸收分光光度法分别测定了其K、Na、Mg、Fe、Cu、Mn、Zn、Co、Ni、Pd 10种金属元素的含量,确立了样品消解试剂、微波消解条件,并对样品进行了精密度和回收率试验。结果表明,相对标准偏差在0.772 8%~6.813 7%之间,回收率在94.0%~109.9%之间,钮子根茎、叶中均含有丰富的K、Na、Mg、Fe、Cu、Mn、Zn等金属元素,Co、Ni等有益微量元素的含量次之,Pd的含量最低。 相似文献