全文获取类型
收费全文 | 11167篇 |
免费 | 785篇 |
国内免费 | 7篇 |
出版年
2024年 | 9篇 |
2023年 | 37篇 |
2022年 | 129篇 |
2021年 | 223篇 |
2020年 | 166篇 |
2019年 | 219篇 |
2018年 | 336篇 |
2017年 | 280篇 |
2016年 | 430篇 |
2015年 | 700篇 |
2014年 | 727篇 |
2013年 | 830篇 |
2012年 | 1025篇 |
2011年 | 946篇 |
2010年 | 600篇 |
2009年 | 529篇 |
2008年 | 686篇 |
2007年 | 672篇 |
2006年 | 582篇 |
2005年 | 551篇 |
2004年 | 511篇 |
2003年 | 437篇 |
2002年 | 350篇 |
2001年 | 192篇 |
2000年 | 179篇 |
1999年 | 131篇 |
1998年 | 74篇 |
1997年 | 50篇 |
1996年 | 40篇 |
1995年 | 29篇 |
1994年 | 20篇 |
1993年 | 28篇 |
1992年 | 29篇 |
1991年 | 25篇 |
1990年 | 20篇 |
1989年 | 19篇 |
1988年 | 16篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 13篇 |
1982年 | 13篇 |
1981年 | 6篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
982.
983.
Parthiban P Pallela R Kim SK Park DH Jeong YT 《Bioorganic & medicinal chemistry letters》2011,21(22):6678-6686
A series of twenty 2,6-diarylpiperidin-4-one O-methyloximes were synthesized with fluoro/chloro/bromo/methyl/methoxy/ethoxy/isopropyl substituents on various positions of the phenyl at C-2 and C-6 in association with/without methyl substituent on the secondary amino group and methyl/ethyl/isopropyl substituents on the active methylene centers. Regardless of their substitution all compounds predominantly exist in the chair conformation except 3m, which adopts a twist-boat conformation. All the synthesized compounds were evaluated for their in vitro antiproliferative activity against human cervical carcinoma (HeLa) cell line. The cytotoxicity of the test compounds was determined by measuring the number of live cells after 24 h of treatment by MTT assay method. This preliminary SAR suggests some lead molecules 3c-f, 3j-k, 4d-g, and 4i with a scope of further structural optimization of the piperidone pharmacophore toward the development of anticancer drug synthesis. 相似文献
984.
A new type of biosorbent was developed for binding anionic precious metals through cross-linking waste biomass Corynebacterium glutamicum with polyethylenimine (PEI). This biomass was evaluated for the removal and recovery of palladium and compared to commercial adsorbents, such as Amberjet 4200 Cl, Lewatit Monoplus TP 214, SPC-100, and SPS-200. The kinetic experiments revealed that the sorption equilibrium was reached with 30 min for the PEI-modified biomass. The maximum uptake of the biosorbent was 176.8 mg/g, which was calculated using the Langmuir model. The Pd(II) maximum uptake exhibited the following order: Amberjet 4200 Cl > Lewatit Monoplus TP 214 > PEI-modified biomass > SPC-100 > SPS-200. Acidified thiourea in 1.0 M HCl was used to desorb Pd(II) from all of the sorbents examined. 相似文献
985.
Koltun E Richards S Chan V Nachtigall J Du H Noson K Galan A Aay N Hanel A Harrison A Zhang J Won KA Tam D Qian F Wang T Finn P Ogilvie K Rosen J Mohan R Larson C Lamb P Nuss J Kearney P 《Bioorganic & medicinal chemistry letters》2011,21(22):6773-6777
A novel series of potent inhibitors of glucosylceramide synthase are described. The optimization of biochemical and cellular potency as well as ADME properties led to compound 23c. Broad tissue distribution was obtained following oral administration to mice. Thus 23c could be another useful tool compound for studying the effects of GCS inhibition in vitro and in vivo. 相似文献
986.
Our recent study has shown that ubiquinol-cytochrome c reductase binding protein (UQCRB), the 13.4-kDa subunit of mitochondrial complex III, plays a crucial role in hypoxia-induced angiogenesis via mitochondrial reactive oxygen species (ROS)-mediated signaling. Here we report a new synthetic small molecule targeting the mitochondrial oxygen sensor UQCRB that was identified by pharmacophore-based virtual screening and in vitro and in vivo competition binding analyses. 6-((1-Hydroxynaphthalen-4-ylamino)dioxysulfone)-2H-naphtho[1,8-bc]thiophen-2-one (HDNT) binds to the hydrophobic pocket of UQCRB and potently inhibits in vitro angiogenesis of human umbilical vein endothelial cells without cytotoxicity. Furthermore, the binding of HDNT to UQCRB suppressed mitochondrial ROS-mediated hypoxic signal transduction. These results demonstrated that HDNT is a novel synthetic small molecule targeting UQCRB and exhibits anti-angiogenic activity by modulating the oxygen-sensing function of UQCRB. 相似文献
987.
988.
989.
Park JY Jeong HJ Kim YM Park SJ Rho MC Park KH Ryu YB Lee WS 《Bioorganic & medicinal chemistry letters》2011,21(18):5602-5604
As part of our ongoing effort to develop influenza virus neuraminidase (NA) inhibitors from various medicinal plants, we utilized bioassay-guided fractionation to isolated six alkylated chalcones (1-6) from Angelica keiskei. Xanthokeistal A (1) emerged as new compound containing the rare alkyl substitution, 6,6-dimethoxy-3-methylhex-2-enyl. When we tested the ability of these individual alkyl substituted chalcones to inhibit influenza virus NA hydrolysis, we found that 2-hydroxy-3-methyl-3-butenyl alkyl (HMB) substituted chalcone (3, IC(50)=12.3 μM) showed most potent inhibitory activity. The order of potency of substituted alkyl groups on for NA inhibition was HMB>6-hydroxyl-3,7-dimethyl-octa-2,7-dienyl>dimethylallyl>geranyl. All NA inhibitors screened were found to be reversible noncompetitive inhibitors. 相似文献
990.