全文获取类型
收费全文 | 228篇 |
免费 | 16篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 16篇 |
2020年 | 6篇 |
2019年 | 15篇 |
2018年 | 11篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 18篇 |
2014年 | 9篇 |
2013年 | 14篇 |
2012年 | 13篇 |
2011年 | 21篇 |
2010年 | 10篇 |
2009年 | 10篇 |
2008年 | 10篇 |
2007年 | 16篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1998年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有244条查询结果,搜索用时 31 毫秒
71.
13C incorporation into signature fatty acids as an assay for carbon allocation in arbuscular mycorrhiza 总被引:1,自引:0,他引:1
Olsson PA van Aarle IM Gavito ME Bengtson P Bengtsson G 《Applied and environmental microbiology》2005,71(5):2592-2599
The ubiquitous arbuscular mycorrhizal fungi consume significant amounts of plant assimilated C, but this C flow has been difficult to quantify. The neutral lipid fatty acid 16:1omega5 is a quantitative signature for most arbuscular mycorrhizal fungi in roots and soil. We measured carbon transfer from four plant species to the arbuscular mycorrhizal fungus Glomus intraradices by estimating (13)C enrichment of 16:1omega5 and compared it with (13)C enrichment of total root and mycelial C. Carbon allocation to mycelia was detected within 1 day in monoxenic arbuscular mycorrhizal root cultures labeled with [(13)C]glucose. The (13)C enrichment of neutral lipid fatty acid 16:1omega5 extracted from roots increased from 0.14% 1 day after labeling to 2.2% 7 days after labeling. The colonized roots usually were more enriched for (13)C in the arbuscular mycorrhizal fungal neutral lipid fatty acid 16:1omega5 than for the root specific neutral lipid fatty acid 18:2omega6,9. We labeled plant assimilates by using (13)CO(2) in whole-plant experiments. The extraradical mycelium often was more enriched for (13)C than was the intraradical mycelium, suggesting rapid translocation of carbon to and more active growth by the extraradical mycelium. Since there was a good correlation between (13)C enrichment in neutral lipid fatty acid 16:1omega5 and total (13)C in extraradical mycelia in different systems (r(2) = 0.94), we propose that the total amount of labeled C in intraradical and extraradical mycelium can be calculated from the (13)C enrichment of 16:1omega5. The method described enables evaluation of C flow from plants to arbuscular mycorrhizal fungi to be made without extraction, purification and identification of fungal mycelia. 相似文献
72.
73.
Nayeli Monterrosas-Brisson Mayra Zagal-Guzmán Alejandro Zamilpa Enrique Jiménez-Ferrer Margarita Avilés-Flores Macrina Fuentes-Mata Maribel Herrera-Ruiz 《化学与生物多样性》2021,18(3):e2000790
Argemone mexicana L. is a widely used plant in Mexican traditional medicine to treat inflammatory and nervous medical conditions. It has been subjected to several pharmacological and chemical studies in which acute anti-inflammatory activity is indicated. This work aimed at finding an extract and fraction with anti-inflammatory activity by means of 2-O-tetradecanoylphorbol-13-acetate (TPA)-induced auricular edema. Afterward, the extract and the fraction were tested on neuroinflammation caused by lipopolysaccharides (LPS). Treatments obtained from A. mexicana included the methanolic extract (AmMeOH), a fraction extracted with ethyl acetate (AmAcOEt), and four sub-fractions (AmF-1 to AmF-4), which were evaluated in auricular edema with the TPA assay. Both treatments with the most significant inhibitory effect were employed to test these in the LPS neuroinflammation model. AmAcOEt and AmF-3 induced a higher inhibition of edema (%), and both diminished ear inflammation when viewed under a microscope. These treatments also raised an increase in spleen, but not in brain of mice with neuroinflammation. They were able to decrease the concentration of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) in both organs. Furthermore, the accumulation of amyloid-β (Aβ) in hippocampus was not visible. AmF-3 contains the flavonoids isoquercetin, luteolin, and rutin, the former being the most concentrated. 相似文献
74.
Jean Pierre Schatzmann Peron Auriléia Aparecida de Brito Mayra Pelatti Wesley Nogueira Brand?o Luana Beatriz Vitoretti Flávia Regina Greiffo Elaine Cristina da Silveira Manuel Carneiro Oliveira-Junior Mariangela Maluf Lucila Evangelista Silvio Halpern Marcelo Gil Nisenbaum Paulo Perin Carlos Eduardo Czeresnia Niels Olsen Saraiva Camara Flávio Aimbire Rodolfo de Paula Vieira Mayana Zatz Ana Paula Ligeiro de Oliveira 《PloS one》2015,10(8)
Cigarette smoke-induced chronic obstructive pulmonary disease is a very debilitating disease, with a very high prevalence worldwide, which results in a expressive economic and social burden. Therefore, new therapeutic approaches to treat these patients are of unquestionable relevance. The use of mesenchymal stromal cells (MSCs) is an innovative and yet accessible approach for pulmonary acute and chronic diseases, mainly due to its important immunoregulatory, anti-fibrogenic, anti-apoptotic and pro-angiogenic. Besides, the use of adjuvant therapies, whose aim is to boost or synergize with their function should be tested. Low level laser (LLL) therapy is a relatively new and promising approach, with very low cost, no invasiveness and no side effects. Here, we aimed to study the effectiveness of human tube derived MSCs (htMSCs) cell therapy associated with a 30mW/3J—660 nm LLL irradiation in experimental cigarette smoke-induced chronic obstructive pulmonary disease. Thus, C57BL/6 mice were exposed to cigarette smoke for 75 days (twice a day) and all experiments were performed on day 76. Experimental groups receive htMSCS either intraperitoneally or intranasally and/or LLL irradiation either alone or in association. We show that co-therapy greatly reduces lung inflammation, lowering the cellular infiltrate and pro-inflammatory cytokine secretion (IL-1β, IL-6, TNF-α and KC), which were followed by decreased mucus production, collagen accumulation and tissue damage. These findings seemed to be secondary to the reduction of both NF-κB and NF-AT activation in lung tissues with a concomitant increase in IL-10. In summary, our data suggests that the concomitant use of MSCs + LLLT may be a promising therapeutic approach for lung inflammatory diseases as COPD. 相似文献
75.
76.
Marina Inés Flamini Gisel Valeria Gauna Mayra Lis Sottile Beatriz Silvina Nadin Angel Matias Sanchez Laura María Vargas‐Roig 《Journal of cellular and molecular medicine》2014,18(6):1113-1123
Breast cancer is the most common malignancy in women and the appearance of distant metastases produces the death in 98% of cases. The retinoic acid receptor β (RARβ) is not expressed in 50% of invasive breast carcinoma compared with normal tissue and it has been associated with lymph node metastasis. Our hypothesis is that RARβ protein participates in the metastatic process. T47D and MCF7 breast cancer cell lines were used to perform viability assay, immunobloting, migration assays, RNA interference and immunofluorescence. Administration of retinoic acid (RA) in breast cancer cells induced RARβ gene expression that was greatest after 72 hrs with a concentration 1 μM. High concentrations of RA increased the expression of RARβ causing an inhibition of the 60% in cell migration and significantly decreased the expression of migration‐related proteins [moesin, c‐Src and focal adhesion kinase (FAK)]. The treatment with RARα and RARγ agonists did not affect the cell migration. On the contrary, the addition of the selective retinoid RARβ‐agonist (BMS453) significantly reduced cell migration comparable to RA inhibition. When RARβ gene silencing was performed, the RA failed to significantly inhibit migration and resulted ineffective to reduce moesin, c‐Src and FAK expressions. RARβ is necessary to inhibit migration induced by RA in breast cancer cells modulating the expression of proteins involved in cell migration. 相似文献
77.
78.
Rojas-Rejn Oscar A. Poggi-Varaldo Hctor M. Ramos-Valdivia Ana C. Martnez-Jimnez Alfredo Cristiani-Urbina Eliseo de la Torre Martnez Mayra Ponce-Noyola Teresa 《Journal of industrial microbiology & biotechnology》2011,38(1):257-264
Derepressed mutant PR-22 was obtained by N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) mutagenic treatment of Cellulomonas flavigena PN-120. This mutant improved its xylanolytic activity from 26.9 to 40 U mg−1 and cellulolytic activity from 1.9 to 4 U mg−1; this represented rates almost 2 and 1.5 times higher, respectively, compared to its parent strain growing in sugarcane bagasse.
Either glucose or cellobiose was added to cultures of C. flavigena PN-120 and mutant PR-22 induced with sugarcane bagasse in batch culture. The inhibitory effect of glucose on xylanase activity
was more noticeable for parent strain PN-120 than for mutant PR-22. When 20 mM glucose was added, the xylanolytic activity
decreased 41% compared to the culture grown without glucose in mutant PR-22, whereas in the PN-120 strain the xylanolytic
activity decreased by 49% at the same conditions compared to its own control. Addition of 10 and 15 mM of glucose did not
adversely affect CMCase activity in PR-22, but glucose at 20 mM inhibited the enzymatic activity by 28%. The CMCase activity
of the PN-120 strain was more sensitive to glucose than PR-22, with a reduction of CMCase activity in the range of 20–32%.
Cellobiose had a more significant effect on xylanase and CMCase activities than glucose did in the mutant PR-22 and parent
strain. Nevertheless, the activities under both conditions were always higher in the mutant PR-22 than in the PN-120 strain.
Enzymatic saccharification experiments showed that it is possible to accumulate up to 10 g l−1 of total soluble sugars from pretreated sugarcane bagasse with the concentrated enzymatic crude extract from mutant PR-22. 相似文献
79.
Soto FR Vuaden ER de Paula Coelho C Bonamin LV de Azevedo SS Benites NR de Barros FR Goissis MD Ortiz D'Ávila Assumpção ME Visintin JA Marques MG 《In vitro cellular & developmental biology. Animal》2011,47(3):205-209
It has been speculated that the homeopathic treatment of sperm cells in order to improve semen quality could be promising. However, few data is available and its use in spermatozoa requires investigation. It is well established that mitochondrial membrane potential is an important viability parameter of spermatozoa and it is intimately related to reproductive efficiency. In this manner, new technologies in order to improve the activity of sperm cells and, finally, the fecundity of swine herds are of extremely importance. Due to the lack of knowledge of homeopathic treatment effect on spermatozoa, the aim of the present study was to verify the effect of three different homeopathic treatments on viability of boar sperm cells. Three homeopathic treatments composed by Pulsatila CH6, Pulsatila and Avena CH6, Avena CH6 and one control treatment (sucrose) were added to diluted boar semen, which were cooled for 24 or 48 h. Interestingly, no positive effect of homeopathic treatments was observed over semen viability. However, it was demonstrated that the 24 h of cooling storage provided more viable sperm cells when compared to the 48-h period. This effect of storage period on sperm viability was assessed by intact plasmatic membrane, intact acrosome and mitochondrial membrane potential evaluation. 相似文献
80.