全文获取类型
收费全文 | 858篇 |
免费 | 30篇 |
国内免费 | 3篇 |
专业分类
林业 | 123篇 |
农学 | 35篇 |
基础科学 | 1篇 |
97篇 | |
综合类 | 43篇 |
农作物 | 29篇 |
水产渔业 | 138篇 |
畜牧兽医 | 351篇 |
园艺 | 12篇 |
植物保护 | 62篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 27篇 |
2020年 | 21篇 |
2019年 | 14篇 |
2018年 | 24篇 |
2017年 | 28篇 |
2016年 | 27篇 |
2015年 | 36篇 |
2014年 | 37篇 |
2013年 | 50篇 |
2012年 | 48篇 |
2011年 | 67篇 |
2010年 | 33篇 |
2009年 | 34篇 |
2008年 | 51篇 |
2007年 | 47篇 |
2006年 | 39篇 |
2005年 | 44篇 |
2004年 | 46篇 |
2003年 | 56篇 |
2002年 | 30篇 |
2001年 | 25篇 |
2000年 | 13篇 |
1999年 | 13篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有891条查询结果,搜索用时 15 毫秒
881.
Atsushi Ishihara 《Journal of Pesticide Science》2021,46(4):382
Plants synthesize and accumulate a wide variety of compounds called secondary metabolites. Secondary metabolites serve as chemical barriers to protect plants from pathogens and herbivores. Antimicrobial secondary metabolites are accumulated to prevent pathogen infection. These metabolites are classified into phytoalexins (induced in response to pathogen attack) and phytoanticipins (present prior to pathogen infection). The antimicrobial compounds in the grass family (Poaceae) were studied from the viewpoint of evolution. The studies were performed at three hierarchies, families, genera, and species and include the following: 1) the distribution of benzoxazinoids (Bxs) in the grass family, 2) evolutionary replacement of phytoanticipins from Bxs to hydroxycinnamic acid amide dimers in the genus Hordeum, and 3) chemodiversity of flavonoid and diterpenoid phytoalexins in rice. These studies demonstrated dynamic changes in secondary metabolism during evolution, indicating the adaptation of plants to their environment by repeating scrap-and-build cycles. 相似文献
882.
883.
Vinicius Henrique Bello Felipe Barreto da Silva Luís Fernando Maranho Watanabe Eduardo Vicentin Cristiane Muller Regiane Cristina Oliveira de Freitas Bueno Jessica Costa Santos Bruno Rossitto De Marchi Angélica Maria Nogueira Valdir Atsushi Yuki Julio Massaharu Marubayashi Maria Márcia Pereira Sartori Marcelo Agenor Pavan Murad Ghanim Renate Krause-Sakate 《Plant pathology》2021,70(6):1508-1520
Since the detection of Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) species in Brazil in the early 1990s, this whitefly has been the predominant species and the main viral vector in the country. In this work, whiteflies were collected from commercial soybean fields near and far from greenhouses where Mediterranean (MED) species had previously been detected infesting vegetable crops. Results indicated that MEAM1 was the predominant whitefly species in soybean in most sampling sites, while MED was found colonizing soybean plants in open field conditions alone and/or with MEAM1 in several places. Among the tested insects, MED species was mostly detected harbouring the facultative endosymbiont Hamiltonella. We also detected cowpea mild mottle virus (CPMMV) infecting soybean plants. Transmission assays demonstrated that MED species was more efficient transmitting CPMMV from beans to beans and from soybean to soybean plants than MEAM1, while MEAM1 was more efficient in transmitting the virus from soybean to bean than MED. Performance assays indicated that adult emergence of both species on CPMMV-infected soybean plants was higher when compared with the emergence on healthy plants. Moreover, nonviruliferous MED and MEAM1 adults preferred to settle more often on healthy plants, while viruliferous adults settled more often on CPMMV-infected soybean plants. As MED has already been found in soybean open fields in São Paulo and Paraná States, Brazil, and it is a good vector of CPMMV, we anticipate problems related to whitefly management and to increase in the incidence of the virus in soybean. 相似文献
884.
The sterile insect technique is an environmentally friendly method to control and even eradicate agricultural and veterinary insect pests without using chemical pesticides in excess. However, the continuous production and release of sterile insects is economically costly and eradication programs using sterile insects have not always been successful owing to the incomplete mating ability of the sterile insects. Here we focus on the theory and empirical findings of interspecific negative mating interaction, known as reproductive interference, to develop a more cost‐effective and value‐added pest management program. We suggest that sterile insects can be used for simultaneous control of both wild‐type conspecifics and closely related pest species by taking advantage of the fact that, when species recognition abilities are incomplete, courtship and mating are often misdirected toward heterospecies. This new approach might help mitigate economic damage and human health crises caused by pest insects. © 2018 Society of Chemical Industry 相似文献
885.
Waleed A Abdel-Naime Atsushi Kimishima Andi Setiawan John Refaat Fahim Mostafa A. Fouad Mohamed Salah Kamel Masayoshi Arai 《Marine drugs》2020,18(11)
The tumor microenvironment is a nutrient-deficient region that alters the cancer cell phenotype to aggravate cancer pathology. The ability of cancer cells to tolerate nutrient starvation is referred to as austerity. Compounds that preferentially target cancer cells growing under nutrient-deficient conditions are being employed in anti-austerity approaches in anticancer drug discovery. Therefore, in this study, we investigated physcion (1) and 2-(2′,3-epoxy-1′,3′,5′-heptatrienyl)-6-hydroxy-5-(3-methyl-2-butenyl) benzaldehyde (2) obtained from a culture extract of the marine-derived fungus Aspergillus species (sp.), which were isolated from an unidentified marine sponge, as anti-austerity agents. The chemical structures of 1 and 2 were determined via spectroscopic analysis and comparison with authentic spectral data. Compounds 1 and 2 exhibited selective cytotoxicity against human pancreatic carcinoma PANC-1 cells cultured under glucose-deficient conditions, with IC50 values of 6.0 and 1.7 µM, respectively. Compound 2 showed higher selective growth-inhibitory activity (505-fold higher) under glucose-deficient conditions than under general culture conditions. Further analysis of the mechanism underlying the anti-austerity activity of compounds 1 and 2 against glucose-starved PANC-1 cells suggested that they inhibited the mitochondrial electron transport chain. 相似文献
886.
Yen Thi Bich Nguyen Akihiko Kamoshita Van Thi Hai Dinh Hirotaka Matsuda Hisashi Kurokura 《Paddy and Water Environment》2017,15(1):37-48
This study was carried out to identify the vulnerability of rice production to salinity intrusion arising from climate change in Giao Thuy, a coastal district of Nam Dinh Province, located in Red River Delta in Vietnam. From the analysis of historical climate data at Nam Dinh city, both mean maximum and minimum temperatures increased by about 0.3 and 0.1 °C per decade, respectively, during the period of 1961–2010. Salt concentration of the river water was higher at the irrigation gate closer to river mouth (Con Nhat) than at the upstream gate (Ha Mieu), which generally increased from 2003 to 2012, with the average maximum concentration up to 2.13 % at Con Nhat gate in 2010. The salt water concentration in the riverside field outside the dyke reached 3.6 %, while among the fields within dyke the salinity was only 0.7 % at maximum in January 2013, and the values were higher in paddy fields close to the dyke than far from the dyke. Average yield among the selected 27 fields from 2011 summer to 2013 spring rice was higher in spring rice (748 g m?2) but lower in summer rice (417 g m?2) mainly due to unfavorable weather such as cold spell at flowering and flood at harvesting time. Rice yield was lowest in general in the most downstream commune Giao Thien, and was significantly lower in field located close to the dyke than those far from the dyke. This spatial variability of rice yield may not be directly attributable to salinity, but to the other factors such as shift of irrigation intake gate to further upstream and/or different management such as less input of N fertilizer and use of traditional local variety. 相似文献
887.
Giacomo Zaccone Gioele Capillo Jorge Manuel Oliveira Fernandes Viswanath Kiron Eugenia Rita Lauriano Alessio Alesci Patrizia Lo Cascio Maria Cristina Guerrera Michal Kuciel Krystyna Zuwala Jose Manuel Icardo Atsushi Ishimatsu Ryosuke Murata Takafumi Amagai Antonino German Marialuisa Aragona 《Marine drugs》2022,20(2)
Antimicrobial peptides (AMPs) are found widespread in nature and possess antimicrobial and immunomodulatory activities. Due to their multifunctional properties, these peptides are a focus of growing body of interest and have been characterized in several fish species. Due to their similarities in amino-acid composition and amphipathic design, it has been suggested that neuropeptides may be directly involved in the innate immune response against pathogen intruders. In this review, we report the molecular characterization of the fish-specific AMP piscidin1, the production of an antibody raised against this peptide and the immunohistochemical identification of this peptide and enkephalins in the neuroepithelial cells (NECs) in the gill of several teleost fish species living in different habitats. In spite of the abundant literature on Piscidin1, the biological role of this peptide in fish visceral organs remains poorly explored, as well as the role of the neuropeptides in neuroimmune interaction in fish. The NECs, by their role as sensors of hypoxia changes in the external environments, in combination with their endocrine nature and secretion of immunomodulatory substances would influence various types of immune cells that contain piscidin, such as mast cells and eosinophils, both showing interaction with the nervous system. The discovery of piscidins in the gill and skin, their diversity and their role in the regulation of immune response will lead to better selection of these immunomodulatory molecules as drug targets to retain antimicrobial barrier function and for aquaculture therapy in the future. 相似文献
888.
Huifeng Ren Yuichi Okamoto Huijuan Jia Ryoji Fukuda Atsushi Kobayashi Sumio Goto Hideaki Endo Tetsuhito Hayashi 《Fisheries Science》2008,74(1):187-192
ABSTRACT: Hepatopancreases were washed four times with 2% acetic acid solution. In both the washed hepatopancreases and the supernatant of the washing solution, the residual cadmium (Cd) concentration was in accordance with the required standard for organic fertilizers. Hepatopancreases do not naturally contain high levels of nitrogen, but they do contain several amino acids which are useful for cultivation, and these were retained during the washing process. Although the condensed precipitate of the washing solution contained a considerable amount of Cd, Cd elution levels at the time of final disposal met judgment standard for special management industrial waste as a result of kneading and immobilizing with chelating adsorbent for treatment of contaminated soil. The volume of the precipitate of the washing solution was one-fifth of the original hepatopancreas, and the solid waste was suitable for burial at a final disposal site without further treatment. 相似文献
889.
Takashi Nishida Atsushi Matsunaga Norio Onikura Shin Oikawa Akinobu Nakazono 《Fisheries Science》2008,74(2):285-292
ABSTRACT: From 2002 to 2006, the fish fauna associated with sea weeds drifting in the Chikuzen Sea, northern Kyushu, Japan, was examined. The total numbers of species and individuals collected were 51 and 5475, respectively. The five dominant species, accounting for approximately 80% of the total individuals, were Rudarius ercodes , Stephanolepis cirrhifer , Petroscirtes breviceps , Sebastes thompsoni and Paramonacanthus japonicus . The number of species and individuals increased significantly with the increase in water temperature, reaching maxima during early summer and autumn, respectively. Combining the present and previous data (∼50 years ago), the appearance patterns of the fishes associated with drifting sea weed were classified into the following four types: (i) long periods (continuously for 3 months or more) and autumn (LA); (ii) spring (SP); (iii) summer (SU); and (iv) rare (R). In more than half of the species, there were no changes in the appearance patterns between the present and previous studies. However, in the present study, the appearance patterns of several species changed from LA to R ( Oplegnathus punctatus and Kyphosus cinerascens ) and from R to LA and SU ( Abudefduf vaigiensis and Hyperoglyphe japonica , respectively). 相似文献
890.
Keishi Matsuda Shinsuke Torisawa Tomonori Hiraishi Katsutaro Yamamoto 《Fisheries Science》2008,74(3):562-572
ABSTRACT: The visual acuity, visual axis and visual accommodation of pointhead flounder, slime flounder, and red halibut were determined to obtain basic knowledge for developing appropriate fishing gear and fishing methods for sustainable fisheries. Each of these species has a different ecotype in terms of habitat, depth and prey species. Thus, it was hypothesized that they may differ in terms of visual acuity, visual axis and visual accommodation. Few studies have compared these characters in flatfishes from different ecotypes. We used histological methods to determine visual acuity (i.e. cone cell density) and visual axis (i.e. cone cell distribution) in each of these species. The maximum visual acuity was 0.127 in pointhead flounder (total length, TL 344 mm), 0.092 in slime flounder (TL 372 mm) and 0.109 in red halibut (TL 336 mm). Based on the cone cell distribution in the retina, the visual axis was upward and forward in pointhead flounder, forward and downward in slime flounder, and downward in red halibut. Finally, the mean angle of lens movement was −2° in pointhead flounder, −13° in slime flounder and −32° in red halibut. This measurement of lens movement indicated that the average near-point distance was 0.87 × TL in pointhead flounder, 0.65 × TL in slime flounder and 1.02 × TL in red halibut. At similar TL (336–355 mm), the visual acuity of these species differs depending on the direction in which they are looking. 相似文献