首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   179篇
  免费   28篇
  2023年   1篇
  2022年   12篇
  2021年   8篇
  2020年   6篇
  2019年   6篇
  2018年   13篇
  2017年   11篇
  2016年   16篇
  2015年   5篇
  2014年   13篇
  2013年   20篇
  2012年   10篇
  2011年   12篇
  2010年   5篇
  2009年   6篇
  2008年   5篇
  2007年   4篇
  2006年   9篇
  2005年   1篇
  2004年   5篇
  2003年   2篇
  2002年   2篇
  2001年   1篇
  1999年   1篇
  1998年   2篇
  1996年   1篇
  1992年   2篇
  1991年   2篇
  1990年   4篇
  1988年   1篇
  1986年   1篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1976年   3篇
  1973年   3篇
  1972年   1篇
  1966年   1篇
  1965年   2篇
排序方式: 共有207条查询结果,搜索用时 15 毫秒
201.
This study examined the performances of 21 cassava cultivars in two cropping seasons on the field against root rot disease and the yield in cassava-maize intercrop. Data were collected on number of root/plant, weight of root (t/ha) and disease severity (DS) on rotted roots at 12 and 16 months after planting (MAP), respectively. There were significant (P ≤ 0.05) differences for DS at 12 and 16 MAP in both seasons with cultivar TMS 97/JW2 having the least DS score. TMS 97/JW2 was resistant to the root rot pathogen, while eleven other cultivars were moderately resistant to the disease at 16 MAP. There was no consistency in the roots weight for the cultivars over the two cropping seasons but higher roots weight was recorded at 16 MAP than 12 MAP with different cultivars having highest roots weight at these periods. Intercropping maize with cassava does not have any management potential on root rot development.  相似文献   
202.
Abstract

The use of liquid chromatography coupled with mass spectrometry (LC-MS/MS) is advantageous in in-vivo receptor occupancy assays at pre-clinical drug developmental stages. Relatively, its application is effective in terms of high throughput, data reproducibility, sensitivity, and sample processing. In this perspective, we have evaluated the use of FTC-146 as a non-radiolabelled tracer to determine the sigma-1 receptor occupancy of test drugs in mice brain. Further, the brain and plasma exposures of test drug were determined at their corresponding occupancies. In this occupancy method, the optimized tracer treatment (sacrification) time after intravenous administration was 30?min. The tracer dose was 3?µg/kg and specific brain regions of interest were frontal cortex, pons and midbrain. Mice were pretreated orally with SA4503, fluspidine, haloperidol, and donepezil followed by tracer treatment. Among the test drugs, SA4503 was used as positive control group at its highest test dose (7?mg/kg, intraperitoneal). There was a dose-dependent decrease in brain regional FTC-146 binding in pretreated mice. From the occupancy curves of SA4503, fluspidine, haloperidol, and donepezil the effective dose (ED50) value ranges are 0.74–1.45, 0.09–0.11, 0.11–0.12, and 0.07–0.09?mg/kg, respectively. Their corresponding brain effective concentration (EC50) values are 74.3–132.5, 3.4–3.7, 122.5–139.5, and 8.8–11.0?ng/g and plasma EC50 values are 34.3–53.7, 0.08–0.10, 7.8–9.5, and 0.6–0.7?ng/mL. Brain regional distribution and binding inhibition upon pretreatment were comparable with data reported with labeled [18F]FTC-146. Drug exposures were simultaneously determined and correlated with sigma-1 occupancy from the same experiment. Wide category drugs can be assayed for sigma-1 receptor engagement and their correlation with exposures aid in clinical development.  相似文献   
203.
This study was undertaken to identify and characterize the globally expressed microRNAs (miRNAs) involved in interleukin-1β (IL-1β)-induced joint damage and to predict whether miRNAs can regulate the catabolic effects in osteoarthritis (OA) chondrocytes. Out of 1347 miRNAs analyzed by microarrays in IL-1β-stimulated OA chondrocytes, 35 miRNAs were down-regulated, 1 miRNA was up-regulated, and the expression of 1311 miRNAs remained unchanged. Bioinformatics analysis showed the key inflammatory mediators and key molecular pathways are targeted by differentially expressed miRNAs. Novel miRNAs identified could have important diagnostic and therapeutic potentials in the development of novel therapeutic strategies for pain managements in OA.  相似文献   
204.
Salinity is a significant constraint for plant survival and productivity. Therefore, an immediate solution to this problem is sought to meet the human population''s food demands. Recently, Menadione sodium bisulphite (MSB) has emerged as a significant regulator of plant defense response under abiotic stress. Studies on MSB are scarce, and a few reports on salinity (Arabidopsis and okra) and cadmium stress (okra) are present in the literature. However, these studies did not include the impact of MSB on physiological and plant water relation attributes, critical mediators of plant survival, and yield production under stress. Our results studied the impact of MSB on wheat administered to NaCl salinity in hydroponics medium. We used two wheat cultivars (salt-sensitive MH-97 and salt-tolerant Millat-2011, based on our pre-experimental studies). Seeds were primed in different MSB doses [control (unprimed), hydroprimed, 5, 10, 20, and 30 mM]. Salinity significantly diminished growth, chlorophyll molecules, photosynthesis, total free amino acids, water and turgor potentials, K, Ca, and P contents of wheat when administered NaCl salinity in the nutrient solution. Besides, a noteworthy accretion was present in oxidative stress markers [hydrogen peroxide & malondialdehyde], proline, ascorbic acid, antioxidant enzyme activities, and Na+ accumulation under salinity. Moreover, MSB noticeably enhanced chlorophyll molecules, proline, and oxidative defense to improve photosynthesis, plant water relations, and diminish specific ions toxicity. Our results manifested better defense regulation in salt-administered plants primed with 5 and 10 mM MSB. Our findings strongly advocated the use of MSB in improving plant salinity tolerance, particularly in wheat.  相似文献   
205.
206.
Fungal endophyte-grass associations are diverse and complex. Some endophytes (e.g. Neotyphodium spp.) reproduce asexually by growing vegetatively into host seeds and many of these vertically-transmitted endophytes form mutualisms with their hosts by providing high levels of alkaloids, such as lolines, that reduce herbivore performance. Additionally, Neotyphodium coenophialum provides wound-inducible herbivore resistance through increased production of lolines. Neotyphodium likely evolved from Epichloë spp. which are sexually reproducing endophytes that are transmitted horizontally to the next host generation through production of stromata (fruiting bodies), which sterilize host grasses. We asked if wound-inducible resistance like that in N . coenophialum also occurs in the ancestral, sexually reproducing Epichloë glyceriae , which infects Glyceria striata . Host grasses were damaged by fall armyworm caterpillars, artificially cut, or left undamaged. An aphid bioassay tested the plant's toxicity to herbivores, expression of lolc (a gene in the loline biosynthesis pathway) was quantified using real-time RT-PCR, and loline concentration was quantified using gas chromatography and mass spectrometry. Artificially-damaged plants supported fewer live aphids, had greater lolc mRNA expression, and greater loline concentration than undamaged plants. Herbivore-damaged plants supported intermediate performance by aphids, low lolc mRNA expression, and minimal loline concentration. Our study is the first to demonstrate sexual endophytes can produce lolines following wounding. This suggests wound-induced responses are ancestral within the Epichloë / Neotyphodium clade and reveals a trait of grass endophytes that may have predisposed them for the evolution of defensive mutualisms with their hosts.  相似文献   
207.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号