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   155篇
  免费   9篇
林业   16篇
农学   1篇
基础科学   4篇
  28篇
综合类   4篇
农作物   10篇
水产渔业   24篇
畜牧兽医   53篇
园艺   7篇
植物保护   17篇
  2023年   3篇
  2022年   2篇
  2021年   3篇
  2020年   6篇
  2019年   3篇
  2018年   7篇
  2017年   8篇
  2016年   8篇
  2015年   6篇
  2014年   7篇
  2013年   16篇
  2012年   13篇
  2011年   13篇
  2010年   12篇
  2009年   12篇
  2008年   7篇
  2007年   8篇
  2006年   11篇
  2005年   4篇
  2004年   2篇
  2003年   2篇
  2002年   4篇
  2001年   2篇
  1998年   1篇
  1995年   1篇
  1969年   2篇
  1968年   1篇
排序方式: 共有164条查询结果,搜索用时 31 毫秒
101.
Stereology is a method for examining two-dimensional objects as three-dimensional objects. The aim of this study was to offer volume values for thoracic segments in ducks by means of stereological methods. This study examined the data obtained from stereological analysis of the total volume and grey and white matter volume values of the thoracic segment, a part of the adult duck spinal cord with a weight of 3–4 kg. In the study, study samples consisted of 10 adult ducks (Anas) used without gender discrimination. To perfuse all of the animals, 10% formaldehyde was utilised. The perfused animals were kept in 10% formaldehyde for one week. The spinal cord was uncovered following the removal of arcus vertebrae parts of thoracic vertebrae in the thoracic part of dissected ducks. Tissue samples of thoracic segments were taken; 5-µm-thick cross sections from these tissue samples were taken via microtome. Attention was paid to obtaining samples at the ratio of 1/250 by taking 12 cross sections from each segment. The cross sections were subjected to haematoxylin-eosin staining. Photographs of all cross sections were taken using a microscope. The volume values of all tissue and grey and white matter structures in each thoracic segment of the spinal cord were calculated. The total volume, grey and white matter volume densities in thoracic segments of ducks, as well as the data obtained as a result of proportioning volume values of one another are represented in the conclusion section of this study.  相似文献   
102.
The vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), is one of the main pests in vineyards. At present biological control of the pest is based on the release of hymenopterous parasitoids and coccinellid predators. The effectiveness of an entomopathogenic fungus, Isaria farinosa, as an alternative biological control agent on vine mealybug P. ficus was investigated by using different inoculum densities and different relative humidity levels. The fungus caused more than 80% mortality at 95% relative humidity and at 1 × 108 conidia ml?1 inoculum density. The mortality effects of the fungus decreased in lower humidity levels and lower spore densities. The inhibitory effects of common fungicides, used in vineyards, on I. farinosa were also investigated. Sulphur, copper oxychloride, fosetyl-Al and chlorothalonil did not decrease the effectiveness of I. farinosa as a pathogen of vine mealybug. With the application of tebuconazole, penconazole and mancozeb, the most inhibitory fungicides on the entomopathogen, the mortality rates of mealybugs, inoculated with I. farinosa, decreased from 86% to 42%, 34% and 45%, respectively, in the adult females; from 94% to 51%, 45% and 45%, respectively, in the first nymphal stages; and from 86% to 56%, 49% and 63%, respectively, in ovisacs.  相似文献   
103.
104.
Interactive effects of silicon (Si) and high boron (B) on growth and yield of tomato (Lycopercison esculentum cv. ‘191 F1’) plants were studied. Treatments were: 1) control (B1), normal nutrient solution including 0.5 mg L?1 B (boron), 2) B1 +Si treatment: 0.5 mg L?1 boron plus 2 mM Si, 3) B2 treatment: 3.5 mg L?1 B, 4) B2 +Si treatment: 3.5 mg L?1 B plus 2 mM Si, 5) B3 treatment: 6.5 mg L?1 B, and 6) B3 +Si: 6.5 mg L?1 B plus 2 mM Si. High B reduced dry matter, fruit yield and chlorophyll (Chl) in tomato plants compared to the control treatment, but increased the proline accumulation. Supplementary Si overcame the deleterious effects of high B on plant dry matter, fruit yield and chlorophyll concentrations. High B treatments increased the activities of superoxide dismutase (SOD; EC 1.15.1.1), peroxidase (POD; EC. 1.11.1.7) and polyphenol oxidase (PPO; EC 1.10.3.1). However, supplementary Si in the nutrient solution containing high B reduced SOD and PPO activities in leaves, but POD activity remained unchanged. These data suggest that excess B-induced oxidative stress and alterations in the antioxidant enzymes. Boron (B) concentrations increased in leaves and roots in the elevated B treatment as compared to the control treatment. Concentrations of calcium (Ca) and potassium (K) were significantly lower in the leaves of plants grown at high B than those in the control plants. Supplementing the nutrient solution containing high B with 2 mM Si increased both nutrients in the leaves. These results indicate that supplementary Si can mitigate the adverse effects of high B on fruit yield and whole plant biomass in tomato plants.  相似文献   
105.
Abstract

The effects of Alcaligenes 637Ca, Agrobacterium A18, Staphylococcus MFDCa1, MFDCa2, Bacillus M3 and Pantoea FF1 were tested on peach cv. ‘Elegant Lady’ on GF677 and Nemaguard rootstocks. Average increases in citric, malic, oxalic, butyric and fumaric acid in the leaf were obtained from rhizobacterial root inoculations of 33.1, 17.5, 21.7, 26.5, and 44.7% in Elegant Lady/Nemaguard, respectively. FF1 showed the highest FC-R activity in the roots of Nemaguard (112.4?nmol?FW?gr?1?hr?2) and GF677 (162?nmol?FW?gr?1?hr?2). The highest FC-R activity in the leaf was with MFDCa2 in Elegant Lady/Nemaguard (57.1?nmol?FW?gr?1?hr?2) and 637Ca in Elegant Lady/GF677 (87.9?nmol?FW?gr?1?hr?2). PGPR strains used in this study expressed increased leaf organic acid content, FC-R activity in the roots and leaf, increased active Fe content in the leaf, and possessed a great potential for the improvement of iron availability to plants.  相似文献   
106.
Meagre, Argyrosomus regius, is a candidate marine fish species for aquaculture diversification, presenting a high economic value in the Mediterranean. Tolerance of juvenile meagre to nitrite (NO2‐N) was determined relating to temperature. Fish (3.2 ± 0.6 g and 5.4 ± 0.9 cm) were exposed to different NO2‐N concentrations in a series of acute toxicity tests by the static renewal method at three temperatures (18, 22, and 26 C) at a pH of 8.0. Low temperature clearly increased tolerance to NO2‐N (P < 0.05). The 96‐h median lethal concentration (LC50) values of NO2‐N were 177.63, 139.55, and 49.61 mg/L, at 18, 22, and 26 C, respectively. The safe levels of NO2‐N for juvenile meagre were estimated to be 17.7, 13.9, and 4.9 mg/L at 18, 22, and 26 C, respectively (P < 0.05). This study indicates A. regius is more sensitive to nitrite than other marine fish species cultured in the Mediterranean.  相似文献   
107.
Bartonella henselae is the causative agent of cat scratch disease (CSD) in humans. Cats are the main reservoir of this bacterium and may infect humans through scratches and bites. The purpose of this study was to determine the B. henselae seroprevalence in cats in Turkey. A total of 298 cats blood samples were collected from six different provinces of Turkey. Sera were tested for the presence of anti-B. henselae IgG antibodies by indirect fluorescent antibody test (IFA). The seroprevalence of B. henselae was 27.9% (83/298) for the cats examined in this study. The seroprevalence of cats by province was significantly higher in Bursa (41.3%), Adana (33.9%), Aydin (27.5%) and Burdur (32.3%) than in Kayseri (17.9%) and Istanbul (12.5%). Statistically significant differences were not observed between cat sexes and living conditions of cats. The results revealed that B. henselae is an important zoonotic pathogen in Turkey.  相似文献   
108.
This study describes the expression of heat shock protein70 (HSP70) and alpha-basic-crystallin (α-BC) and their association with apoptosis and some related adaptor proteins in the pathogenesis of foot-and-mouth disease virus (FMDV)-induced myocarditis in lambs. HSP70 was generally overexpressed in the myocardial tissues and inflammatory cells of FMDV-induced myocarditis with differential accumulation and localization in same hearts when compared to non-foot-and-mouth disease control hearts. α-BC immunolabeling showed coarse aggregations in the Z line of the cardiomyocytes in FMDV-infected hearts in contrast to control hearts. Overall, the results of this study show that the anti-apoptotic proteins, HSP70 and α-BC, were overexpressed with increased apoptosis in FMDV-infected heart tissues. Both proteins failed to protect the cardiomyocytes from apoptosis as defense mechanisms to the FMDV during the infection, suggesting that the virus is able to increase apoptosis via both downregulation and/or upregulation of these anti-apoptotic proteins.  相似文献   
109.
The pecten oculi is a highly vascularized and pigmented organ that projects from the optic disc into the vitreous body in the avian eye. In this study, the pecten oculi of Turkey's native Gerze chicken was examined by light and scanning electron microscopy. Furthermore, the localization of some adherens junction components (E-cadherin and pan-cadherin) in intact vessels of the blood–retina barrier was investigated by immunohistochemistry. In the Gerze chicken, the pecten oculi was a thin structure, which was located over the head of the discus nervi optici and projected from the retina into the corpus vitreum. The pecten oculi consisted of 18–21 highly vascularized pleats, joined apically by a bridge and resembled an accordion in appearance. Hyalocytes and melanocytes were observed around the small and large vessels. The morphometric data of the pecten oculi showed that there were no statistical differences in terms of sex. The immunohistochemical analysis of the pecten oculi, which is used as a model for the investigation of the formation and maturation of the barrier properties in the central nervous system, revealed cytoplasmic E-cadherin and pan-cadherin immunoreactivity in the endothelial cells of the small, large and capillary vessels. These observations suggest that while the morphological and histological structure of the Gerze chicken's pecten oculi was generally similar to that of other diurnal domestic birds, the pecten oculi, a model system for vascular differentiation and the blood–retina barrier, expressed different cadherins.  相似文献   
110.
ABSTRACT

Salix anatolica Ziel. & D. Tomasz., belonging to Salicaceae family, is endemic to the East Mediterranean in Turkey. Its threat category has been assessed as vulnerable based on the red list criteria of IUCN. Therefore, it is necessary to protect and reproduce. Within the scope of this study, propagation of the species is carried out by cutting which is one of the vegetative propagation methods. Under greenhouse media conditions, effects of different concentrated doses of auxins were examined on rooting percentage (RP), number of roots (RN) per rooted cuttings, and root length (RL) related to male and female stem cuttings. At the end of this study, the highest RP in the cuttings taken from the female individuals was 100% in Control and IAA 1000 ppm treatments, this value was also obtained as 100% in Control + Wounding and IAA 1000 ppm treatments in the cuttings taken from the male individuals. While hormone applications were effective on the RP in male individuals, they were effective on the RN and RL in female individuals. In addition, wounding has had a positive effect on both male and female individuals.  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