全文获取类型
收费全文 | 468篇 |
免费 | 30篇 |
专业分类
化学 | 375篇 |
晶体学 | 1篇 |
力学 | 11篇 |
数学 | 23篇 |
物理学 | 88篇 |
出版年
2024年 | 3篇 |
2023年 | 6篇 |
2022年 | 56篇 |
2021年 | 67篇 |
2020年 | 25篇 |
2019年 | 24篇 |
2018年 | 8篇 |
2017年 | 12篇 |
2016年 | 34篇 |
2015年 | 18篇 |
2014年 | 20篇 |
2013年 | 38篇 |
2012年 | 40篇 |
2011年 | 32篇 |
2010年 | 21篇 |
2009年 | 11篇 |
2008年 | 18篇 |
2007年 | 15篇 |
2006年 | 9篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1974年 | 2篇 |
1965年 | 1篇 |
1917年 | 2篇 |
1903年 | 1篇 |
排序方式: 共有498条查询结果,搜索用时 15 毫秒
411.
Isshadiba Faikah Mustafa Mohd Zobir Hussein Abu Seman Idris Nur Hailini Zainol Hilmi Sharida Fakurazi 《Molecules (Basel, Switzerland)》2021,26(19)
Reports on fungicide-based agronanochemicals in combating disastrous basal stem rot disease in the oil palm industry are scant. Herein, we describe the potential of fungicide nanodelivery agents based on hexaconazole-micelle systems produced using three different surfactants; sodium dodecylbenze sulfonate (SDBS), sodium dodecyl sulfate (SDS) and Tween 80 (T80). The resulting nanodelivery systems were characterized and the results supported the encapsulation of the fungicide into the micelles of the surfactants. We have investigated in detail the size-dependent effects of the as-synthesized micelles towards the inhibition growth of Ganoderma Boninense fungi. All the nanodelivery systems indicate that their size decreased as the surfactant concentration was increased, and it directly affects the fungal inhibition. It was also found that Tween 80, a non-ionic surfactant gave the lowest effective concentration, the EC50 value of 2, on the pathogenic fungus Ganoderma boninense compared to the other anionic surfactants; SDBS and SDS. This study opens up a new generation of agronanofungicide of better efficacy for Ganoderma disease treatment. 相似文献
412.
413.
414.
415.
Ayse Nur Esen Sevilay Haciyakupoglu Sema Erenturk Marie Kubešová Jan Kučera 《Journal of Radioanalytical and Nuclear Chemistry》2016,307(1):179-185
In this study, the effect of contact time, pH, competitive cations and equilibrium study of adsorption on Slovak illite/smectite Dolná Ves was investigated. The sorption processes was studied using batch techniques under aerobic conditions with radioisotope indication using 63Ni as a radiotracer. Studied material has proved to be as promising candidate for practically used as a barrier against the spread of undesirable substances in the environment landfill as insulating material of toxic and hazardous waste. 相似文献
416.
417.
Azmi Seyhun Kipcak Emek Moroydor Derun Sabriye Piskin 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(1):175-188
In this study, ulexite, probertite found within sodium–calcium borates and borax, and tincalconite found within sodium borates retrieved from different regions in Turkey are evaluated for their neutron irradiation performances. Characterisations were performed using XRD, FT-IR, Raman spectroscopy. B2O3 contents were determined experimentally, structural water contents and surface morphologies were determined using DTA/TG and SEM. Neutron transmission values and total macroscopic cross-sections were determined using 239Pu–Be source moderated in a howitzer. Neutron transmission values from lowest to highest were found to be as follows: secondary ulexite (K?rka), tincalconite (K?rka), ulexite (Kestelek), ulexite (K?rka), borax (K?rka), probertite (Kestelek) and ulexite (Bigadiç). 相似文献
418.
Mohd Noor Hidayat Adenan Latifah Saiful Yazan Annie Christianus Nur Fariesha Md Hashim Suzita Mohd Noor Shuhaimi Shamsudin Farah Jehan Ahmad Bahri Khairuddin Abdul Rahim 《Molecules (Basel, Switzerland)》2021,26(6)
Large doses of ionizing radiation can damage human tissues. Therefore, there is a need to investigate the radiation effects as well as identify effective and non-toxic radioprotectors. This study evaluated the radioprotective effects of Kelulut honey (KH) from stingless bee (Trigona sp.) on zebrafish (Danio rerio) embryos. Viable zebrafish embryos at 24 hpf were dechorionated and divided into four groups, namely untreated and non-irradiated, untreated and irradiated, KH pre-treatment and amifostine pre-treatment. The embryos were first treated with KH (8 mg/mL) or amifostine (4 mM) before irradiation at doses of 11 Gy to 20 Gy using gamma ray source, caesium-137 (137Cs). Lethality and abnormality analysis were performed on all of the embryos in the study. Immunohistochemistry assay was also performed using selected proteins, namely γ-H2AX and caspase-3, to investigate DNA damages and incidences of apoptosis. KH was found to reduce coagulation effects at up to 20 Gy in the lethality analysis. The embryos developed combinations of abnormality, namely microphthalmia (M), body curvature and microphthalmia (BM), body curvature with microphthalmia and microcephaly (BMC), microphthalmia and pericardial oedema (MO), pericardial oedema (O), microphthalmia with microcephaly and pericardial oedema (MCO) and all of the abnormalities (AA). There were more abnormalities developed from 24 to 72 h (h) post-irradiation in all groups. At 96 h post-irradiation, KH was identified to reduce body curvature effect in the irradiated embryos (up to 16 Gy). γ-H2AX and caspase-3 intensities in the embryos pre-treated with KH were also found to be lower than the untreated group at gamma irradiation doses of 11 Gy to 20 Gy and 11 Gy to 19 Gy, respectively. KH was proven to increase the survival rate of zebrafish embryos and exhibited protection against organ-specific abnormality. KH was also found to possess cellular protective mechanism by reducing DNA damage and apoptosis proteins expression. 相似文献
419.
Sideritis niveotomentosa Hub. -Mor. is a local endemic species belonging to the Lamiaceae family. In this study, GC/MS analysis, total antioxidant capacity and anticancer effects of different extracts obtained from S. niveotomentosa were investigated comparatively. Total phenolic contents of extracts were determined by the Folin–Ciocalteu method, total flavonoid contents by aluminum chloride method, and also the free radical scavenging activities of the extracts by DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay. The cytotoxic effect of the extracts was studied via MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay on DLD1, HL60 and ARH77 cell lines. Pro-apoptotic gene expression levels were also tested in the most sensitive cell line ARH77 by Real-Time PCR. The expression levels of 4 pro-apoptotic genes, APAF, BAX, CASP3, and HRK were found to be upregulated in ARH77 cells that were treated extracts. Results showed that methanolic extracts contain more phenolic content than acetone extracts, consistent with DPPH results. As a result, Sideritis niveotomentosa extracts, especially methanolic extracts, are rich in phenolic content and have a strong radical scavenging effect. In addition, the extracts showed selective effects on cell lines. This study is pioneering in terms of future studies, and the findings provide hope for future experimentation. 相似文献
420.
Dispersive liquid-liquid microextraction (DLLME) was combined with high-performance liquid chromatography-diode-array detector (HPLC-DAD) for the extraction and quantitation of three major capsaicinoids (i.e. capsaicin, dihydrocapsaicin and nordihydrocapsaicin) from pepper (Capsicum annuum L.). Chloroform (extraction solvent, 100 μL), acetonitrile (disperser solvent, 1250 μL) and 30 s extraction time were found optimum. The analytes were back-extracted into 300 μL of 50 mM sodium hydroxide/ methanol, 45/55% (v/v), within 15 s before being injected into the instrument. Enrichment factors ranged from 3.3 to 14.7 and limits of detection from 5.0 to 15.0 µg g-1. Coefficients of determination (R2) and %RSD were higher than 0.9962 and lower than 7.5%, respectively. The proposed method was efficiently applied for the extraction and quantitation of the three capsaicinoids in six cultivars of Capsicum annuum L. with percentage relative recoveries in the range of 92.0%–108.0%. DLLME was also scaled up for the isolation of the three major capsaicinoids providing purity greater than 98.0% as confirmed by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) analysis, which significantly reduced the extraction time and organic solvent consumption. 相似文献