全文获取类型
收费全文 | 2308篇 |
免费 | 151篇 |
国内免费 | 5篇 |
专业分类
化学 | 1946篇 |
晶体学 | 21篇 |
力学 | 43篇 |
数学 | 145篇 |
物理学 | 309篇 |
出版年
2024年 | 1篇 |
2023年 | 21篇 |
2022年 | 45篇 |
2021年 | 52篇 |
2020年 | 55篇 |
2019年 | 68篇 |
2018年 | 47篇 |
2017年 | 46篇 |
2016年 | 100篇 |
2015年 | 71篇 |
2014年 | 106篇 |
2013年 | 186篇 |
2012年 | 224篇 |
2011年 | 248篇 |
2010年 | 152篇 |
2009年 | 118篇 |
2008年 | 158篇 |
2007年 | 135篇 |
2006年 | 114篇 |
2005年 | 101篇 |
2004年 | 85篇 |
2003年 | 73篇 |
2002年 | 75篇 |
2001年 | 29篇 |
2000年 | 35篇 |
1999年 | 14篇 |
1998年 | 14篇 |
1997年 | 14篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 11篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 2篇 |
排序方式: 共有2464条查询结果,搜索用时 46 毫秒
971.
972.
973.
Thao Quyen Cao Zhiming Liu Linsha Dong Hwan Lee Wonmin Ko Le Ba Vinh Nguyen Quoc Tuan Youn-Chul Kim Jae Hak Sohn Joung Han Yim Dong-Sung Lee Hyuncheol Oh 《Molecules (Basel, Switzerland)》2022,27(9)
Microglia play a significant role in immune defense and tissue repair in the central nervous system (CNS). Microglial activation and the resulting neuroinflammation play a key role in the pathogenesis of neurodegenerative disorders. Recently, inflammation reduction strategies in neurodegenerative diseases have attracted increasing attention. Herein, we discovered and evaluated the anti-neuroinflammatory potential of compounds from the Antarctic fungi strain Aspergillus sp. SF-7402 in lipopolysaccharide (LPS)-stimulated BV2 cells. Four metabolites were isolated from the fungi through chemical investigations, namely, 5-methoxysterigmatocystin (1), sterigmatocystin (2), aversin (3), and 6,8-O-dimethylversicolorin A (4). Their chemical structures were elucidated by extensive spectroscopic analysis and HR-ESI-MS, as well as by comparison with those reported in literature. Anti-neuroinflammatory effects of the isolated metabolites were evaluated by measuring the production of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in LPS-activated microglia at non-cytotoxic concentrations. Sterigmatocystins (1 and 2) displayed significant effects on NO production and mild effects on TNF-α and IL-6 expression inhibition. The molecular mechanisms underlying this activity were investigated using Western blot analysis. Sterigmatocystin treatment inhibited NO production via downregulation of inducible nitric oxide synthase (iNOS) expression in LPS-stimulated BV2 cells. Additionally, sterigmatocystins reduced nuclear translocation of NF-κB. These results suggest that sterigmatocystins present in the fungal strain Aspergillus sp. are promising candidates for the treatment of neuroinflammatory diseases. 相似文献
974.
Hyeon Seok Oh Taehyung Kim Dong-Hyeon Gu Tae Suk Lee Tae Hwan Kim Soyoung Shin Beom Soo Shin 《Molecules (Basel, Switzerland)》2022,27(6)
Nafamostat, a synthetic serine protease inhibitor, has been used for the treatment of inflammatory diseases such as pancreatitis. Recently, an increasing number of studies have shown the promising antiviral effects of nafamostat for the treatment of coronavirus disease-19 (COVID-19). This study aimed to develop a novel liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis and to characterize the pharmacokinetics of nafamostat in rats. Nafamostat in the rat plasma was extracted by solid phase extraction, and 13C6-nafamostat was used as an internal standard. The quantification limit of nafamostat in the rat plasma was 0.5 ng/mL. The LC-MS/MS method was fully validated and applied to characterize the pharmacokinetics of nafamostat in rats. Following intravenous injection (2 mg/kg), nafamostat in the plasma showed a multiexponential decline with an average elimination half-life (t1/2) of 1.39 h. Following oral administration of nafamostat solutions (20 mg/kg) in 10% dimethyl sulfoxide (DMSO) and in 10% DMSO with 10% Tween 80, nafamostat was rapidly absorbed, and the average oral bioavailability was 0.95% and 1.59%, respectively. The LC-MS/MS method and the pharmacokinetic information of nafamostat could be helpful for the further preclinical and clinical studies of nafamostat. 相似文献
975.
Min Yeong Park Sang Eun Ha Hun Hwan Kim Pritam Bhagwan Bhosale Abuyaseer Abusaliya Se Hyo Jeong Joon-Suk Park Jeong Doo Heo Gon Sup Kim 《Molecules (Basel, Switzerland)》2022,27(12)
Inflammation is a severe topic in the immune system and play a role as pro-inflammatory mediators. In response to such inflammatory substances, immune cells release cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). Lipopolysaccharide (LPS) is known as an endotoxin in the outer membrane of Gram-negative bacteria, and it catalyzes inflammation by stimulating the secretion of inflammatory-mediated cytokines such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) by stimulated immune cells. Among the pathways involved in inflammation, nuclear factor kappa (NF-кB) and mitogen-activated protein kinases (MAPKs) are important. NF-kB is a diploid composed of p65 and IkBα and stimulates the pro- gene. MAPKs is a family consisting of the extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38, JNK and p38 play a role as proinflammatory mediators. Thus, we aim to determine the scutellarein (SCU) effect on LPS stimulated RAW264.7 cells. Furthermore, since scutellarein has been shown to inhibit the SARS coronavirus helicase and has been used in Chinese medicine to treat inflammatory disorders like COVID-19, it would be required to examine scutellarein’s anti-inflammatory mechanism. We identified inflammation-inducing substances using western blot with RAW264.7 cells and SCU. And we discovered that was reduced by treatment with SCU in p-p65 and p-IκBα. Also, we found that p-JNK and p-ERK were also decreased but there was no effect in p-p38. In addition, we have confirmed that the iNOS was also decreased after treatment but there is no change in the expression of COX-2. Therefore, this study shows that SCU can be used as a compound to treat inflammation. 相似文献
976.
Soonbum Park Eun A Cho Jung Nyeo Chun Da Young Lee Sanghoon Lee Mi Yeon Kim Sang Mun Bae Su In Jo So Hee Lee Hyun Ho Park Tae Min Kim Insuk So Sang-Yeob Kim Ju-Hong Jeon 《Experimental & molecular medicine》2022,54(8):1225
Crizotinib is a clinically approved tyrosine kinase inhibitor for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harboring EML4-ALK fusion. Crizotinib was originally developed as an inhibitor of MET (HGF receptor), which is involved in the metastatic cascade. However, little is known about whether crizotinib inhibits tumor metastasis in NSCLC cells. In this study, we found that crizotinib suppressed TGFβ signaling by blocking Smad phosphorylation in an ALK/MET/RON/ROS1-independent manner in NSCLC cells. Molecular docking and in vitro enzyme activity assays showed that crizotinib directly inhibited the kinase activity of TGFβ receptor I through a competitive inhibition mode. Cell tracking, scratch wound, and transwell migration assays showed that crizotinib simultaneously inhibited TGFβ- and HGF-mediated NSCLC cell migration and invasion. In addition, in vivo bioluminescence imaging analysis showed that crizotinib suppressed the metastatic capacity of NSCLC cells. Our results demonstrate that crizotinib attenuates cancer metastasis by inhibiting TGFβ signaling in NSCLC cells. Therefore, our findings will help to advance our understanding of the anticancer action of crizotinib and provide insight into future clinical investigations.Subject terms: Non-small-cell lung cancer, Targeted therapies 相似文献
977.
Yeon Jae Jo Dan Hee Yoo In Chul Lee Junsoo Lee Heon Sang Jeong 《Molecules (Basel, Switzerland)》2022,27(17)
We focused on the functional components, antioxidant activity, skin-whitening, and anti-wrinkle properties of subcritical and supercritical water (SCW)-treated rutin. Rutin treatments were performed at the following temperature and pressure conditions: 200 °C/15 bar, 300 °C/100 bar, and 400 °C/250 bar. ABTS and DPPH radical scavenging activities and reducing power presented their highest values (1193.72 mg AAE/g, 728.73 mg AAE/g, and 0.65, respectively) at 300 °C/100 bar. The tyrosinase inhibitory activity of SCW-treated rutin was 21.72–60.05% at 1 mg/mL. The ethyl acetate fraction showed 14.91% melanin inhibitory activity at a concentration of 10 µg/mL compared to the α-MSH treatment group. The protein expression inhibition rates of MITF, tyrosinase, TRP-1, and TRP-2 in the ethyl acetate fractions were 14.05%, 72%, 93.05%, and 53.44%, respectively, at a concentration of 10 µg/mL, compared to the control. These results indicate that SCW treatment could be used to develop cosmetic materials and functional food with physiological activity, and that SCW-treated rutin can be used as a skin-whitening cosmetic material. 相似文献
978.
Fermented bean products are used worldwide; most of the products are made using only a few kinds of beans. However, the metabolite changes and contents in the beans generally used during fermentation are unrevealed. Therefore, we selected four different beans (soybean, Glycine max, GM; wild soybean, Glycine soja, GS; common bean, Phaseolus vulgaris, PV; and hyacinth bean, Lablab purpureus, LP) that are the most widely consumed and fermented with Aspergillus oryzae. Then, metabolome and multivariate statistical analysis were performed to figure out metabolite changes during fermentation. In the four beans, carbohydrates were decreased, but amino acids and fatty acids were increased in the four beans as they fermented. The relative amounts of amino acids were relatively abundant in fermented PV and LP as compared to other beans. In contrast, isoflavone aglycones (e.g., daidzein, glycitein, and genistein) and DDMP-conjugated soyasaponins (e.g., soyasaponins βa and γg) were increased in GM and GS during fermentation. Notably, these metabolite changes were more significant in GS than GM. In addition, the increase of antioxidant activity in fermented GS was significant compared to other beans. We expect our research provides a basis to extend choice for bean fermentation for consumers and food producers. 相似文献
979.
Oriana Brea Dr. Inés Corral Prof. Dr. Otilia Mó Prof. Dr. Manuel Yáñez Prof. Dr. Ibon Alkorta Prof. Dr. José Elguero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18322-18325
Through the use of high‐level ab initio and density functional calculations it is shown that 1,8‐diBeX‐naphthalene (X=H, F, Cl, CN, CF3, C(CF3)3) derivatives behave as anion sponges, very much as 1,8‐bis(dimethylamino)naphthalene derivatives behave as proton sponges. The electron‐deficient nature of the BeX substituents, which favors strong charge transfer from the anion towards the former, results in anion affinities that are among the largest ones reported for single neutral molecules. 相似文献
980.