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   208篇
  免费   11篇
林业   14篇
农学   8篇
基础科学   3篇
  58篇
综合类   24篇
农作物   9篇
水产渔业   20篇
畜牧兽医   45篇
园艺   3篇
植物保护   35篇
  2024年   1篇
  2023年   5篇
  2022年   2篇
  2021年   6篇
  2020年   4篇
  2019年   10篇
  2018年   4篇
  2017年   4篇
  2016年   5篇
  2015年   5篇
  2014年   1篇
  2013年   6篇
  2012年   11篇
  2011年   20篇
  2010年   10篇
  2009年   9篇
  2008年   23篇
  2007年   16篇
  2006年   9篇
  2005年   16篇
  2004年   9篇
  2003年   15篇
  2002年   10篇
  2001年   1篇
  2000年   1篇
  1998年   2篇
  1996年   5篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1986年   1篇
  1984年   1篇
  1982年   1篇
  1955年   1篇
  1870年   1篇
排序方式: 共有219条查询结果,搜索用时 15 毫秒
121.
122.
123.
124.
Recently, some preclinical and clinical studies have demonstrated the ability of brown seaweeds in reducing the risk factors for metabolic syndrome. Here, we analyzed the beneficial effect of a nutraceutical formulation containing a phytocomplex extracted from seaweeds and chromium picolinate in animal models of liver steatosis of differing severities (rats with non-alcoholic fatty liver disease (NAFLD) and its complication, non-alcoholic steatohepatitis (NASH)). This treatment led to a significant drop in hepatic fat deposition in both models (p < 0.01 vs. untreated animals), accompanied by a reduction in plasma inflammatory cytokines, such as interleukin 6, tumor necrosis factor α, and C reactive protein, and myeloperoxidase expression in liver tissue. Furthermore, a modulation of the molecular pathways involved in lipid metabolism and storage was demonstrated, since we observed the significant reduction of the mRNA levels of fatty acid synthase, diacylglycerol acyltransferases, the sterol-binding protein SREBP-1, and the lipid transporter perilipin-2, in both treated NAFLD and NASH rats in comparison to untreated ones. In conclusion, this nutraceutical product was effective in reducing liver steatosis and showed further beneficial effects on hepatic inflammation and glycemic control, which were particularly evident in rats characterized by a more severe condition, thus representing a therapeutic option for the treatment of NAFLD and NASH patients.  相似文献   
125.
Toxocara canis (T. canis) is originally a parasite of canine bitches and their pups. The pathogenicity of T. canis infection is enhanced during pregnancy and puppyhood. The aim of this study was to investigate if modification of IFNgamma and IL-10 secretion occurs during infection in pregnant dogs and puppies. Analysis of cytokines secreted could let us hypothesize a role for IL-10 and/or IFNgamma in T. canis infection. We tested T. canis-specific production of IFNgamma and IL-10 by lymphocytes of pregnant dogs and their puppies after in vitro re-exposure to purified excretory/secretory antigen (ESAg) from T. canis. Blood mononuclear cells (BMC) isolated from pregnant dogs and their puppies were cultured in the presence of ESAg. Cultures' supernatants were tested for cytokine levels by ELISA. Results obtained showed that IL-10 concentrations increased during pregnancy in infected animals and in the meantime IFNgamma production decreased. In puppyhood, we observed that, IL-10 concentration decreased with the age of puppies mainly in infected animals while IFNgamma increased. In conclusion, our data suggests that BMC of infected dogs have a particular modification of IL-10 and IFNgamma synthesis. These data could be the basis to design immunotherapeutic approaches.  相似文献   
126.
Objective: To report a surgical implantation of the Vibrant Soundbridge (VSB) middle ear implant in dogs. Study Design: Pilot study. Animals: Dogs (n=3). Methods: A lateral approach to the tympanic bulla was used to insert the floating mass transducer of the VSB into the tympanic bulla. Using microscopic guidance the transducer was moved to and inserted into the round window niche by manipulation through the acoustic bony meatus, after reflection of the tympanic membrane. VSB position was confirmed by computed tomography (CT) imaging. Results: No intraoperative complications occurred and CT images confirmed correct placement of the VSB. Conclusions: A VSB can be safely implanted in the middle of dogs.  相似文献   
127.
128.
129.
Three management units (MUs) are used for stock assessment and fishery regulations of anchoveta Engraulis ringens in Chilean waters (>65% of E. ringens latitudinal range): MU‐I [18–25)°S, MU‐II [25–32)°S and MU‐III [32–42)°S. To evaluate whether these three MUs correspond to separate demographic units (DUs), as well as to estimate mixing rates and spatial distribution of these DUs, we combined three types of otolith natural markers: isotopic signatures (δ13C and δ18O), elemental compositions (Na, Mg, Mn, Sr and Ba) and microstructural indexes. All otolith markers were determined in nuclear and marginal regions of juveniles and adults from cohorts 2012 and 2015. Differences in core region markers indicated spatial segregation between three environmentally distinct nursery areas, probably related to Subtropical Water (MU‐I), Subantarctic Water (MU‐III) and the Subtropical Convergence (MU‐II). Comparison of core and marginal regions, from juvenile and/or adult fish, suggested that adult fish remained nearby nursery areas, separated from fish nursed in other MUs. Nonetheless, ontogenetic migrations from warmer (offshore) nursery habitats to cooler (deeper/more coastal) feeding habitats occurred within MUs. In summary, our results support the consideration of the three MUs as three separate DUs. Estimated mixing rates indicated MU‐II received contributions of 31% from MU‐I and 3% from MU‐III, while complete segregation existed between MU‐I and MU‐III. Such mixing rates between MU‐I and MU‐III seem large enough to justify its further consideration by stock assessment models and management procedures.  相似文献   
130.
Larval growth, age, growth effect and instantaneous mortality were estimated in anchoveta, Engraulis ringens, collected biweekly during the austral winter of 2014 in nearshore waters off Bay of Antofagasta (23°41′W–70°30′S), northern Chile. Through measuring standard length (SL) and sagitta microstructure analysis, it was estimated that the growth rate of E. ringens larvae decreased from June (0.85 mm day?1) to August (0.50 mm day?1). However, the water temperature was homogeneous during the sampling dates (14.6, 15.2, 14.4, and 14.6°C), suggesting that the decelerating larval growth was not linked to changes in sea temperature. Additionally, larvae with slow growth have larger otoliths compared with conspecifics with fast growth (growth effect). Larval mortality rates tended to decrease until the middle of July (0.18 per day) but increased to 0.25 per day in early August, which coincided with lower food availability (i.e., chlorophyll‐a, 2.7–5.6 mg m?3) and a high occurrence of smaller larvae (1.58–11.5 mm). Partial least squares analysis indicates low covariance between the biological and oceanographic variables (PLS: 11.71%), suggesting that other factors, such as parental effects, may explain the abrupt decrease in the larval growth rates.  相似文献   
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