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   183篇
  免费   13篇
林业   19篇
农学   2篇
基础科学   2篇
  29篇
综合类   10篇
农作物   27篇
水产渔业   29篇
畜牧兽医   50篇
园艺   3篇
植物保护   25篇
  2024年   3篇
  2022年   8篇
  2021年   4篇
  2020年   5篇
  2019年   11篇
  2018年   7篇
  2017年   10篇
  2016年   7篇
  2015年   10篇
  2014年   8篇
  2013年   14篇
  2012年   14篇
  2011年   11篇
  2010年   3篇
  2009年   9篇
  2008年   7篇
  2007年   5篇
  2006年   2篇
  2005年   8篇
  2004年   1篇
  2003年   7篇
  2002年   1篇
  2001年   4篇
  2000年   4篇
  1999年   2篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1991年   1篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1979年   1篇
  1977年   2篇
  1975年   1篇
  1973年   3篇
  1971年   3篇
  1969年   1篇
  1966年   1篇
  1965年   3篇
排序方式: 共有196条查询结果,搜索用时 46 毫秒
101.
In this part, 32 plants (rubiaceae tovitaceae) are investigated in a search for local tanning materials. Colour tests along with the chromatographic investigation of the free sugars and phenolic aglycones are given. A conclusion of all the plants previously studied is given discussing the collective data of the colour tests, free sugars and phenolic aglycones separately.
Zusammenfassung In diesem letzten Teil einer Serie von Veröffentlichungen über lokal vorkommende Pflanzen als potentielle Quelle für Gerbstoffe, werden die Untersuchungsergebnisse von weiteren 32 Pflanzen (aus den FamilienRubiaceae bisVitaceae) beschrieben.Farbtests, spezifisch für Tannine, zusammen mit chromatographischen Untersuchungen auf freie Zucker und phenolische Aglykone wurden durchgeführt.Zusammenfassend werden die Ergebnisse aus dem Farbtest, der Analysen auf freie Zucker und phenolische Aglykone an allen bisher in die Untersuchungen einbezogenen Pflanzen diskutiert.

Resume Trente-deux plantes (des familiesRubiaceae à Vitaceae) ont été examinées afin de déterminer le site de localisation des tannins. Les tests colorés et les résultats chromatographiques des sucres libres et des aglycones phénoliques sont décrits.Une conclusion de toutes les plantes déjà examinées du point de vue des tests colorés est présentée ainsi qu'une discussion générale des résultats individuels des sucres libres et des aglycones phénoliques.


Part VI, this journal: XX, 4 :297–309, 1971  相似文献   
102.
Journal of Plant Diseases and Protection - The ability of the nematode antagonistic, mutualistic endo-phyte Fusarium oxysporum strain 162, to colonize the endorhiza of different Fusarium wilt...  相似文献   
103.
This study explores the occurrence of Non-alcoholic Fatty Liver Disease (NAFLD), Insulin Resistance (IR), dyslipidemia and atherogenic ratios in epileptic children and adolescents receiving Valproic Acid (VPA), Carbamazepine (CBZ) or both (combination therapy) compared to healthy controls. Abdominal Computerized Tomography (CT), measurements of serum fasting insulin, glucose, serum lipids and liver enzymes were performed in VPA (n = 14), CBZ (n = 14) or both (n = 10) treated non-diabetic non-obese epileptic patients compared to healthy controls (n = 10). Abdominal CT demonstrated characteristics of fatty liver disease in 42.8% of VPA, in 21.4% of CBZ, in 60% of combination therapy treated patients and none of the healthy controls. All of them were overweight and 53.3% had IR. In conclusion VPA therapy was associated with increased risk of IR and NAFLD, while CBZ therapy was associated with dyslipidemia and combination therapy was associated with all these risks.  相似文献   
104.
Background: Initial studies have shown that low-energy ultrasound stimulates living tissue cells to reduce regeneration or speed up their recovery. The purpose of this study was to examine the effects of various ultrasound parameters on the speed of recovery in injured sciatic nerves NMRI.Methods: NMRI mice (n = 200) with injured left paw, caused by crushing their sciatic nerves, were randomly selected. The animals were exposed to ultrasound radiation with various frequencies, intensities, and exposure time. They were allocated into 20 groups (19 treatment and 1 control groups). Sciatic functional index (SFI) test was used to evaluate the difference between the groups with respect to functional efficiency of the sciatic nerve and its recovery. SFI ، (P=0.000).Results: The results of SFI test obtained from the 14th day showed a significant difference among the groups (P<0.05). On the 14th day after treatment, one of the groups (US11) recovered up to 90%..Conclusion: Altered ultrasound exposure parameters had more favorable outcomes compared with our previous work.Key Words: Sciatic nerve, Ultrasonic therapy, Regeneration  相似文献   
105.
The efficacy of using cottonseed oil (CSO) as a fish oil (FO) substitute in gilthead seabream (Sparus aurata) juveniles feed was evaluated. Fish (BWi 4.0 ± 2.9 g) were fed one of four isoproteic (~48% CP) and isolipidic (~18% L) diets for 9 weeks. Added oil was either FO (control diet, CTRL) or CSO, replacing 50% (CSO50 diet), 60% (CSO60 diet) and 70% (CSO70 diet) of dietary FO. Results indicated that FO replacement by CSO up to 60% level had no detrimental effects on growth or nutritive utilization and composition in fish muscles. Higher CSO intake (CSO70 diet, 56 g kg?1) led to a 16% reduction in weight gain, 14% in feed utilization (FCR) and 57% in muscle n‐3 long‐chain polyunsaturated fatty acids (lc PUFA) as compared with CTRL and to abundant accumulation of lipid within the hepatocytes. Use of CSO altered fatty acid (FA) profiles of muscle and liver. Data suggested utilization of linoleic acid (LOA) by fish and retain of docosahexaenoic acid (DHA) in muscles. Therefore, limits of CSO inclusion as the main source of supplementary dietary lipid, with no negative effects on fish performance or nutritive composition and utilization in muscles, are: 40–48 g kg?1 feed for gilthead seabream juveniles.  相似文献   
106.
107.
In future, prolonged summer drought and heat will constitute a major risk for the cultivation of shallow‐rooting beech in Central Europe and will negatively affect the productivity of beech forests. In a pot experiment under controlled conditions, the influence of long‐term (28 d) water deprivation on nitrogen (N), carbon (C), phosphate (Pi), and ascorbate (ASC) concentrations was examined in leaves and fine roots of beech seedlings (Fagus sylvatica L.) from six provenances originating from Central Europe (Germany: Neidenstein and Illertissen, intermediate habitats), the Balkan peninsula (Croatia: Zagreb and Gospic, wet habitats), and Southeast Europe (Bulgaria: Kotel, Greece: Paikos; dry habitats). The goal of the study was to identify beech provenances well adapted to water limitation during summer drought events. Our results suggest that N might be involved in the alleviation of water scarcity, whereas Pi might become a limiting factor for forest growth during drought periods. Drought stress resulted in significant changes of ASC pools in leaves and fine roots and the ASC redox state. Under well‐watered and under drought conditions, ASC in leaves was the most important factor causing differences between the provenances examined. Finally, a link between P nutrition and the capacity of antioxidative stress defense by ascorbate could be highlighted. Based on observations from this study, beech seedlings from three origins (Paikos, Zagreb, and Neidenstein) might constitute beech provenances well adapted to water shortage in summer. This conclusion is drawn from the high potential of these provenances to alleviate oxidative stress during water shortage.  相似文献   
108.
This paper presents the effects of particle size and mixing ratio on the properties including physical, mechanical, and decay resistance of wood plastic composites (WPCs). In addition, it also presents the effects of immersion temperatures on water absorption (WA) and thickness swelling (TS) of the WPCs. WPCs with a thickness of 6 mm were fabricated from Albizia richardiana King & Prain wood particles and recycled polyethylene terephthalate (PET) by the flat-press method. To prepare the WPCs, two different wood particle sizes (0.5–1.0 and 1.01–2.0 mm) were used along with four different mixing ratios (w/w). Subsequently, the physical properties include density, moisture content, WA, and TS, and mechanical properties include modulus of elasticity (MOE) and modulus of rupture (MOR) of the produced WPCs was evaluated. Furthermore, decay resistance was evaluated by the weight loss percentage method. Moreover, the effects of immersion temperatures on WA and TS of WPCs after 24 h of immersion in water at three different temperatures, i.e., 25, 50, and 75 °C were investigated. Results showed that the wood particle size had impact on WPC’s density (only 6% decreased with the increase of particle size); however, the density decreased by 29% when the wood particle content increased from 40 to 70%. The WA and TS gradually increased with the increase of particle content and decrease of particle size. In addition, WA and TS increased proportionately with increasing immersion temperature from 25 to 75 °C. Furthermore, the highest MOE (2570 N/mm2) was found for the WPCs fabricated from large wood particles having the ration of 50:50 (wood particle:PET). For decay resistance, WPCs consisted of larger particles and higher PET content showed greater resistance against decay. Therefore, it is comprehensible that fabrication of the WPCs from 50% large particles and 50% PET is technically feasible and further improvement of WPC performance like enhancement of MOE and reduction of density using coupling agent and agricultural waste fibers, respectively, in the WPC formulation is recommended.  相似文献   
109.
The degree of similarity between rice milled in a McGill #2 laboratory mill and commercial milling processes was evaluated using eight physical, physicochemical, and end‐use properties. There was no statistical difference between the two milling systems with respect to color parameters L* and a*, final viscosity, texture, and end‐use cooking properties (α = 0.05). Overall, the kernel dimensions of length, width, and thickness were less in the McGill #2 laboratory‐milled rice than the same rice milled commercially. The incidence of bran streaks and peak viscosity values were each higher when the rice sample was milled commercially in 27, and 28, respectively, of the 29 samples by means comparison. The decrease in kernel dimensions and incidence of bran streaks were attributed to the more aggressive nature of the single‐pass, batch milling system of the McGill #2 laboratory mill as compared with multipass, continuous milling systems that are used commercially. Finally, as surface lipid content (SLC) decreased, L* increased and a*, b*, and the incidence of bran streaks decreased for both milling systems.  相似文献   
110.
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