全文获取类型
收费全文 | 276篇 |
免费 | 7篇 |
国内免费 | 5篇 |
专业分类
林业 | 41篇 |
农学 | 16篇 |
基础科学 | 2篇 |
42篇 | |
综合类 | 12篇 |
农作物 | 28篇 |
水产渔业 | 38篇 |
畜牧兽医 | 68篇 |
园艺 | 14篇 |
植物保护 | 27篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 15篇 |
2019年 | 15篇 |
2018年 | 13篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 8篇 |
2013年 | 22篇 |
2012年 | 19篇 |
2011年 | 26篇 |
2010年 | 19篇 |
2009年 | 13篇 |
2008年 | 11篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有288条查询结果,搜索用时 15 毫秒
241.
Md. Hasan Hafizur Rahman Yasuhiro Arima Koichiro Watanabe Hitoshi Sekimoto 《Soil Science and Plant Nutrition》2013,59(2):287-296
A pot experiment was conducted under growth chamber conditions to determine the lower and upper critical levels of boron (B) for plant growth, nodule development, and nodule acetylene reduction activity (ARA) in young soybean plants. Plants of a soybean cultivar, Tachinagaha, were grown in pots containing river sand to which a nutrient solution with different B levels was added and were inoculated with Bradyrhizobium japonicum A1017. At 8, 12, and 16 d after sowing (DAS), among the plants supplied with the solution at 0, 1.0, and 2.0 mg B L-1 , plants with 1.0 mg B L-1 showed the highest values for dry shoot and fresh root weight, root length, total number of developing nodules and meristematic nodules (DMN), and ARA. At 20 DAS plants grown with 11 B levels (0-2.0 mg L-1) were compared. The B critical deficiency levels for soybean dry shoot weight, fresh root weight, root length, DMN, number of complete nodules, and ARA were approximately 46, 35, 34, 57, 60, and 50 mg B kg-1 dry matter, and the critical toxicity levels were approximately 114, 137, 134, 97, 104, and 89 mg B kg-1 dry matter, respectively. The optimum B levels for the growth characters were approximately 34 to 137 mg B kg-1 dry matter. The optimum range of B levels for nodule formation and function was more restricted than that for the growth characters. Based on the results of treatments with various B concentrations, 0.4 mg B L-1 was found to be the concentration most beneficial for all the growth characters including nodule formation at the early stage (20 DAS) of development of soybean plants. 相似文献
242.
Spinach (Spinacea oleracea L. cv. ‘Banarasi’), known to be responsive to potentially toxic elements, was investigated for chromium (Cr6 +) effect on iron metabolism and water relations. After 40 days growth in sand culture, a set of plants was supplied with 100 and 400 μM Cr6 + (potassium dichromate, K2Cr2O7), superimposed over the complete nutrient solution (control). Excess Cr6 + produced visual symptoms of toxicity and increased accumulation of Cr, more in roots than in leaves. Decreased concentration of chlorophylls and the activities of heme enzymes, catalase and peroxidase in excess Cr6 + may suggest interference of Cr in iron metabolism of plants. These changes associated with decrease in iron (Fe) accumulation in Cr6 + treated plants, indicate that by reducing absorption of Fe, Cr6 + impairs the Fe requiring steps of chlorophyll and heme biosynthesis. In spite of lower water saturation deficit, the leaves of Cr6 + treated plants showed a decrease in leaf water potential, associated with increase in diffusive resistance and lowering of transpiration rate along with proline accumulation indicates water stress. The changes observed in water stress parameters in Cr6 + treated plants indicate that excess supply of Cr6 + reduces the physiological availability of water. 相似文献
243.
Md. Mahadhi Hasan Hana Starobova Alexander Mueller Irina Vetter Richard J. Lewis 《Marine drugs》2021,19(2)
The peripheral effects of ω-conotoxins, selective blockers of N-type voltage-gated calcium channels (CaV2.2), have not been characterised across different clinically relevant pain models. This study examines the effects of locally administered ω-conotoxin MVIIA, GVIA, and CVIF on mechanical and thermal paw withdrawal threshold (PWT) in postsurgical pain (PSP), cisplatin-induced neuropathy (CisIPN), and oxaliplatin-induced neuropathy (OIPN) rodent models. Intraplantar injection of 300, 100 and 30 nM MVIIA significantly (p < 0.0001, p < 0.0001, and p < 0.05, respectively) alleviated mechanical allodynia of mice in PSP model compared to vehicle control group. Similarly, intraplantar injection of 300, 100, and 30 nM MVIIA (p < 0.0001, p < 0.01, and p < 0.05, respectively), and 300 nM and 100 nM GVIA (p < 0.0001 and p < 0.05, respectively) significantly increased mechanical thresholds of mice in OIPN model. The ED50 of GVIA and MVIIA in OIPN was found to be 1.8 pmol/paw and 0.8 pmol/paw, respectively. However, none of the ω-conotoxins were effective in a mouse model of CisIPN. The intraplantar administration of 300 nM GVIA, MVIIA, and CVIF did not cause any locomotor side effects. The intraplantar administration of MVIIA can alleviate incision-induced mechanical allodynia, and GVIA and MVIIA effectively reduce OIPN associated mechanical pain, without locomotor side effects, in rodent models. In contrast, CVIF was inactive in these pain models, suggesting it is unable to block a subset of N-type voltage-gated calcium channels associated with nociceptors in the skin. 相似文献
244.
B. Hasan Sontas F.T. Seval Toydemir ?zge Erdogan Gülbin ?ennazli Hayri Ekici 《The Canadian veterinary journal. La revue veterinaire canadienne》2013,54(9):840-844
A 5-year-old, sexually intact poodle bitch was presented with a 2-year history of inguinal mass. A tentative diagnosis of hydrometra/mucometra with inguinal herniation was made and ovariohysterectomy with hernia repair was performed. Both fluid-filled uterine horns, both broad ligaments, and the uterine body were observed to be herniated through the inguinal ring. On histopathology, marked edema and diffuse hemorrhage were diagnosed in the uterus. 相似文献
245.
Delamination is the most common failure mode in laminated composites, due to the reduced strength in the through-the-thickness direction. This paper describes the development of core-and-effect textured glass yarns for improving the bonding strength of laminated glass woven fabric composites. Air-jet texturing introduces bulk and loops in the yarn which provides more contact surface between the fibers and the resin. However, the yarn tenacity decreases after texturing because of the reduced alignment of the filaments. The effects of texturing air pressure, yarn overfeed ratio, yarn linear density and core-sheath ratio were studied in this paper. The tenacity of glass yarns decreased significantly after the texturing process. The reduction was smaller for yarns with a higher core linear density. The effects of texturing air pressure on the tenacity were found to be insignificant. 相似文献
246.
247.
Antibacterial activity and cytotoxicity of extractives from Uvaria hamiltonii stem bark 总被引:2,自引:0,他引:2
The extracts as well as piperolactum C, goniopedaline, 6beta-hydroxystigmasta-4,22-dien-3-one and a mixture of cis- and trans-4-hydroxymelleins obtained from Uvaria hamiltonii stem bark exhibited mild to moderate in vitro antibacterial activity. The results obtained were compared with a standard antibiotic, kanamycin. In a brine shrimp lethality bioassay the pet-ether, dichloromethane, methanol extracts and a major alkaloid, piperolactum C were found to exhibit mild to moderate cytotoxicity. 相似文献
248.
Ornamental plants play an increasingly important role in urban habitats in Turkey. Scale insects are a serious pest group that attack ornamental plants. In this study, a total of 67 species of Coccoidea belonging to 7 families, which are harmful to ornamental plants, are given in Tables 1, 2, and 3. These tables are based on the authors data and on bibliographic sources. The most numerous families are Diaspididae (31), Coccidae (23), Pseudococcidae (7), Eriococcidae (3), and the Margarodidae, Kermesidae and Astereolecaniidae (1). Twenty-one of these species are harmful to flowering fruit and deciduous trees, 5 species are harmful to conifers, while 15 species are important orchard pests. Their hosts and distributions are also taken into consideration. 相似文献
249.
Dr. Hasan Çanakçioglu 《Journal of pest science》1972,45(10):152-154
Zusammenfassung Die Aphiden in den türkischen Forsten (114 Arten in 7 Familien) und deren Wirtspflanzen sowie ihre ö konomische Bedeutung sind in diesem Artikel zusammengestellt. Die wichtigsten Arten sind.Pineus orientalis (Dreyf.),P. pini (Macq.) (Adelgidae);Cinara cedri Mime.,C. palaestinensis H. R. Lamb. (Lachidae);Eriosoma lanuginosum (Hart.) (Pemphigidae);Phyllaphis fagi (L.) (Callaphidae) undAphis craccivora Koch (Aphididae).Weitere in den türkischen Wäldern verbreitete Blattlausarten können orts- und zeitweise von Bedeutung sein.
Summary The aphids of Turkish forests (114 species in 7 families), their host plants and economic importance are summarized. More important species are:Pineus orientalis (Dreyf.),P. pini (Macq.) (Adelgidae);Cinara cedri Mim.,C. palaestinensis H. R. Lamb. (Lachnidae);Eriosoma lanuginosum (Hart.) (Pemphigidae);Phyllaphis fagi (L.) (Callaphididae) andAphis craccivora Koch (Aphididae).The other aphids which are recorded in Turkish forest, in some extent are important species.相似文献
250.
Hasan Mohammad Al-Amin Narayan Gyawali Melissa Graham Mohammad Shafiul Alam Audrey Lenhart Leon E Hugo Gordana Rašić Nigel W Beebe Gregor J Devine 《Pest management science》2023,79(8):2846-2861