全文获取类型
收费全文 | 239篇 |
免费 | 16篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 16篇 |
2019年 | 19篇 |
2018年 | 15篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 9篇 |
2014年 | 14篇 |
2013年 | 26篇 |
2012年 | 25篇 |
2011年 | 16篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 15篇 |
2007年 | 5篇 |
2006年 | 11篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有255条查询结果,搜索用时 15 毫秒
71.
Coumarins are a well-known group of natural products distributed in the plant kingdom especially in the family Apiaceae with various biological activities. Isoarnottinin 4'-glucoside is a simple glycosylated coumarin found previously in a few genera of Apiaceae, and its biological activities have not been previously described in details. In the present paper, the compound was isolated from Prangos uloptera (Apiaceae) leaves using HPLC techniques. Antimicrobial, phytotoxic and cytotoxic activities of the compound were evaluated by disk diffusion, lettuce assay and MTT method. Our results indicated that the compound has high antibacterial effect against Erwinia carotovora, a common plant pathogen with MIC value of 100 microg/mL. The compound also exhibited significant phytotoxic activity against lettuce and modest cytotoxic activity against HeLa cell line with IC50 of 0 .84 mg/mL. It could be concluded that isoamottinin 4'-glucoside may play phytoalexin or allelopathic role for plant and may be a candidate for an antibacterial agent or a bioherbicide. 相似文献
72.
首次报道了伊朗西北部 Varzeghan 附近发现的大型哺乳动物化石,材料包括三趾马和恐象。根据个体大小和形态特征,将三趾马标本暂时分为一个小至中型类似 Hipparion moldavicum 的种和一个中至大型类似 H. prostylum 或 H. dietrichi 的种。Deinotherium giganteum 也出现于这一地区。依据与其他晚中新世地点哺乳动物化石的对比,这些新化石地点的时代推测为吐洛里期( Turolian) 中期或相当于欧洲哺乳动物带的 MN12。 相似文献
73.
Jafari Marjan Shiran Behrouz Rabiei Gholamreza Ravash Rudabeh Sayed Tabatabaei Badraldin Ebrahim Martínez-García Pedro J. Martínez-Gómez Pedro 《Plant Growth Regulation》2022,97(2):357-373
Plant Growth Regulation - Almond is a stone fruit crop belonging to the Rosaceae family, cultivated in the temperate region of the world for its high nutritive valued fruits. In today’s... 相似文献
74.
Marzie Jalali Monfared Farinaz Nasirinezhad Somayeh Ebrahimi-Barough Gholamreza Hasanzade Hooshang Saberi Seyed Mohammad Tavangar Shiva Asadpour Leila Aryan Zahra Barabadi Jafar Ai 《Journal of cellular physiology》2019,234(10):18887-18896
Oligodendrocyte (OL) loss and demyelination occur after spinal cord injury (SCI). Stimulation of remyelination through transplantation of myelinating cells may be effective in improving function. For the repair strategy to be successful, the selection of a suitable cell and maintaining cell growth when cells are injected directly to the site of injury is important. In addition to selecting the type of cell, fibrin hydrogel was used as a suitable tissue engineering scaffold for this purpose. To test the relationship between myelination and functional improvement, the human endometrial stem cells (hEnSCs) were differentiated toward oligodendrocyte progenitor cells (OPCs) using overexpression of miR-219. Adult female Wistar rats were used to induce SCI by using a compression model and were randomly assigned to the following four experimental groups: SCI, Vehicle, hEnSC, and OPC. Ten days after injury, miR-219 overexpressed hEnSC-derived OPCs encapsulated in fibrin hydrogel, as an injectable scaffold, were injected to the injury site. In this study, with a focus on promoting functional recovery after SCI, the Basso-Beattie-Bresnahan test was performed to evaluate the recovery of motor function every week for 10 weeks and the histological assay was then performed. Results showed that the rate of motor function recovery was significantly higher in OPC group compared to SCI and vehicle groups but no marked differences were found between OPC and hEnSC groups, although, the rate of myelination in the OPC group was significantly higher than the other groups. These results demonstrated that remyelination was not the cause of recovery of motor function. 相似文献
75.
Hojjat Samareh Fekri Mehdi Ranjbar Gholamreza Dehghan Noudeh Nazanin Ziasistani 《Luminescence》2019,34(8):870-876
Carboxymethyl cellulose (CMC) is one of the main derivatives of cellulose and is used as a drug carrier for hydrophobic and hydrophilic drugs, imaging in vivo, and biological applications. Encapsulation is a technology in which target compounds are coated with wall compounds to form microcapsules. This study reports a new chemical processing wet method for precipitation and encapsulation of strontium nanoparticles (Sr NPs) within CMC structures using a sonochemical method. Preparation parameters such as microwave power and irradiation time as well as morphology and particle size of Sr NPs were also investigated. Products were characterized by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and atomic force microscopy. In this study, CMC was used as a biological stabilizer in a retentive phase to encapsulate Sr NPs. For the first time, Sr NPs were synthesized using CMC in a cost‐effective, simple, fast, micellation‐assisted, ultrasound method. Sr NPs were encapsulated in green capping agent structures of either 1%, 2% or 3% weight to provide an efficient optical nanostructure with a high yield at wavelengths 200–700 nm for use in in vivo imaging studies. 相似文献
76.
Amir Pachideh Gholamreza Niknam Habibeh Jabbari Reyes Pe?a-Santiago 《Journal of nematology》2015,47(1):67-70
Margollus bokanicus n. sp., collected from natural habitats in Khorasaneh district, Bokan, West Azarbaijan province, Iran, is described. Morphological and morphometric data are provided as well as drawings and light microscopy illustrations. The new species is characterized by a medium size body length (0.60 to 0.73 mm), labial and postlabial sclerotizations, lip region 7-μm wide, offset by constriction and long neck (167 to 207 μm), long pharyngeal basal bulb (27 to 36 μm) or 16% to 17% of total neck length, female genital system monodelphic–opisthodelphic, anterior branch reduced to a uterine sac (26–29 μm) or 1.1 to 1.3 times the body diameter, long posterior uterus (25–28 μm) or 1.1 to 1.3 times the body diameter, V = 40 to 47, cylindroid female tail (17 to 24 μm, c = 31 to 38, c’ = 1.1 to 1.4), and males unknown. This taxon is easily distinguishable from other Margollus species by its smaller general size and more posterior vulva. A compendium of Margollus species is also presented. 相似文献
77.
78.
Ali Reza Hosseininia Maryam Vahabzadeh Marziyeh Rashedinia Bamdad Riahi-Zanjani Gholamreza Karimi 《Mycotoxin Research》2014,30(1):43-46
Sesame seed is one of the main nutrient substances which is used in the food industries of Khorasan Razavi, Iran. Because it is likely that stored sesame seeds are contaminated with mycotoxins, the levels of aflatoxins (AF) in five lots of imported sesame seeds before their distribution to the market were studied during one year. A total of 269 sub-samples were obtained from a total of 9,321 tons of sesame seeds from five importing companies. Aflatoxins at >1 μg/kg were found in 50 % of all samples, but at low levels in most cases, which is illustrated by mean AFB1 and total AF levels of 1.25?±?3.70 and 1.43?±?4.38 μg/kg, respectively. A few (1.9 %) samples exceeded the National Iranian Standard maximum accepted level for AFB1 (5 μg/kg) or total AF (15 μg/kg); the maximum total AF level found in one sample was 48 μg/kg. The results indicate that the risk of a violative AF contamination in imported sesame seeds is not negligible but is currently relatively low. 相似文献
79.
Ivana Jov?evska Neja Zupanec Nina Ko?evar Daniela Cesselli Ne?a Podergajs Clara Limbaeck Stokin Michael P. Myers Serge Muyldermans Gholamreza Hassanzadeh Ghassabeh Helena Motaln Maria Elisabetta Ruaro Evgenia Bourkoula Tamara Lah Turn?ek Radovan Komel 《PloS one》2014,9(11)
Malignant gliomas are among the rarest brain tumours, and they have the worst prognosis. Grade IV astrocytoma, known as glioblastoma multiforme (GBM), is a highly lethal disease where the standard therapies of surgery, followed by radiation and chemotherapy, cannot significantly prolong the life expectancy of the patients. Tumour recurrence shows more aggressive form compared to the primary tumour, and results in patient survival from 12 to 15 months only. Although still controversial, the cancer stem cell hypothesis postulates that cancer stem cells are responsible for early relapse of the disease after surgical intervention due to their high resistance to therapy. Alternative strategies for GBM therapy are thus urgently needed. Nanobodies are single-domain antigen-binding fragments of heavy-chain antibodies, and together with classical antibodies, they are part of the camelid immune system. Nanobodies are small and stable, and they share a high degree of sequence identity to the human heavy chain variable domain, and these characteristics offer them advantages over classical antibodies or antibody fragments. We first immunised an alpaca with a human GBM stem-like cell line prepared from primary GBM cultures. Next, a nanobody library was constructed in a phage-display vector. Using nanobody phage-display technology, we selected specific GBM stem-like cell binders through a number of affinity selections, using whole cell protein extracts and membrane protein-enriched extracts from eight different GBM patients, and membrane protein-enriched extracts from two established GBM stem-like cell lines (NCH644 and NCH421K cells). After the enrichment, periplasmic extract ELISA was used to screen for specific clones. These nanobody clones were recloned into the pHEN6 vector, expressed in Escherichia coli WK6, and purified using immobilised metal affinity chromatography and size-exclusion chromatography. Specific nanobody:antigen pairs were obtained and mass spectrometry analysis revealed two proteins, TRIM28 and β-actin, that were up-regulated in the GBM stem-like cells compared to the controls. 相似文献
80.
Gholamreza Ahmadi Lakalayeh Reza Faridi-Majidi Reza Saber Alireza Partoazar Shahram Ejtemaei Mehr Amir Amani 《AAPS PharmSciTech》2012,13(4):1386-1395
Nanoemulsions are increasingly being investigated for their fascinating capability of loading both hydrophobic and hydrophilic molecules while their stability is still an issue, being affected by various factors. In this study, to evaluate the dominant factors affecting the stability of nanoemulsions, artificial neural networks (ANNs) were implemented. Nanoemulsions of almond oil in water containing oleic acid-coated superparamagnetic iron oxide nanoparticles were prepared using a mixture of Tween 80 and Span 80 as surfactant system and ethanol as a co-surfactant. The ratio of transparency of the samples at 30 min and 7 days after preparation was taken as an indication of the stability of samples. Four independent variables, namely, concentration of nanoparticle, surfactant, oil, and alcohol were investigated to find their relations with the dependent variable (i.e., transparency ratio). Using ANNs modeling, it was concluded that the stability is affected by all variables, with all variables showing reverse effect on the stability beyond an optimum amount.Key words: artificial neural networks, nanoemulsion, optimization, stability, superparamagnetic iron oxide 相似文献