全文获取类型
收费全文 | 482篇 |
免费 | 21篇 |
专业分类
林业 | 31篇 |
农学 | 11篇 |
基础科学 | 2篇 |
37篇 | |
综合类 | 39篇 |
农作物 | 21篇 |
水产渔业 | 40篇 |
畜牧兽医 | 278篇 |
园艺 | 5篇 |
植物保护 | 39篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 17篇 |
2014年 | 13篇 |
2013年 | 16篇 |
2012年 | 28篇 |
2011年 | 23篇 |
2010年 | 12篇 |
2009年 | 9篇 |
2008年 | 12篇 |
2007年 | 25篇 |
2006年 | 25篇 |
2005年 | 30篇 |
2004年 | 27篇 |
2003年 | 19篇 |
2002年 | 18篇 |
2001年 | 18篇 |
2000年 | 16篇 |
1999年 | 21篇 |
1993年 | 1篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 11篇 |
1987年 | 13篇 |
1986年 | 8篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1965年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有503条查询结果,搜索用时 950 毫秒
71.
Effects of relative shoot height and irradiance on shoot and leaf properties of Quercus serrata Thunb. saplings growing in the understory and in gaps were investigated. Photosynthetic photon flux (PPF) at the location of the shoot relative to that in the open (relative PPF; rPPF) and the height of the shoot base relative to tree height (relative height; rHeight) were measured for all current-year shoots of each sapling. Current-year shoot properties (length, leaf area, number of daughter shoots) and mortality, and leaf properties (mass per area (LMA) and nitrogen content per area (N(area))) were examined in relation to rPPF and rHeight. N(area) was used as a proxy for area-based assimilative capacity. Shoot length, leaf area per shoot and number of daughter shoots increased with increasing rHeight, especially in well-lit conditions. Shoot mortality decreased with increasing rHeight and rPPF. Both LMA and N(area) were positively correlated with rPPF, but not rHeight. 相似文献
72.
In many disaster settings, top‐down responses emphasise ‘expert‐led’ solutions that often involve relocating disaster‐affected communities. While the intention might be to move people from harm's way and facilitate recovery, failure to attend to local pre‐disaster circumstances as well as the interplay between power, resilience and vulnerability within and around affected communities often sees resettlement reconfigure as displacement or disconnection. This oversight may even usher in a new phase of dispossession and disadvantage for marginalised groups (particularly in colonial settings). This paper explores experiences in Australia, Japan and Taiwan to reflect on what issues of local sociality, local culture and local resilience need to be attended to in framing ‘better’ disaster responses. 相似文献
73.
Triploid Induction in the Yellowtail Tetra,Astyanax altiparanae,Using Temperature Shock: Tools for Conservation and Aquaculture 下载免费PDF全文
Nadya Soares de Macedo Adamov Nivaldo Ferreira do Nascimento Elayna Cristina Silva Maciel Matheus Pereira‐Santos José Augusto Senhorini Leonardo Luiz Calado Mariana Machado Evangelista Laura Satiko Okada Nakaghi Alan Hertz Marín Guerrero Takafumi Fujimoto George Shigueki Yasui 《Journal of the World Aquaculture Society》2017,48(5):741-750
Triploidization is an interesting tool to produce sterile fish. In the yellowtail tetra, Astyanax altiparanae, this can be applied for aquaculture and surrogate technologies. In this study, we compared the efficacy of cold (2 C) or heat shock (38 C, 40 C, and 42 C) on triploid induction in the yellowtail tetra. The eggs were treated with cold or heat shock, 2 min postfertilization (30 min in cold shock or 2 min in heat shock). Intact embryos served as the control group. Ploidy status was confirmed by karyotyping, flow cytometry, and nuclear diameter of erythrocytes. The hatching rate decreased after cold shock (12.69 ± 15.76%) and heat shock at 42 C (0.35 ± 0.69%) in comparison with the control group (63.19 ± 16.82%). At 38 C and 40 C, hatching rates (61.29 ± 17.73% and 61.75 ± 22.1%, respectively) were not decreased. Only one triploid arose at 38 C (1/80). At 40 C, a high number of triploids arose (72/78). At 42 C, very few embryos developed into the hatching stage. A large number of haploid individuals arose after cold shock (61/75), with only one triploid. Our results indicate that heat shocking of embryos at 40 C is optimum for triploid production in the yellowtail tetra. 相似文献
74.
Ichimi Kazuhiko Honda Miyuki Okada Yuka Tsuzuki Kana Yamaguchi Hitomi 《Fisheries Science》2019,85(3):417-427
Fisheries Science - We carried out surveys to clarify how the density (no. of individuals/m2) and condition factor (CF) of Manila clam Ruditapes philippinarum differ between estuarine tidal flats... 相似文献
75.
Jun Sasaki Megumi Uehara Itaru Sato Hiroshi Satoh Yoshitaka Deguchi Hiroyuki Chida Masahiro Natsuhori Takahisa Murata Kenji Ochiai Kumiko Otani Keiji Okada Nobuhiko Ito 《Animal Science Journal》2019,90(9):1333-1339
To study the effect of ionizing radiation on thyroid glands, 66 Japanese Black cattle residing in the restricted area of the Fukushima Daiichi Nuclear Power Plant in 2013–2017 were pathologically examined. There were no clinical symptoms of thyroid disease in these cattle. Three cases of goiter and seven of atrophy were found in two among the four farms examined. Cases of goiter exhibited normal morphological structure without mass or nodule formation in thyroid glands. Cellular atypia or capsular invasion of the follicular epithelium was absent. The estimated integrated dose of external radiation in goiter cases ranged from maximum 797 mSv to minimum 24 mSv. All lobules in the seven atrophic thyroid glands were affected, but pathological findings, such as inflammatory cell infiltration or stromal fibrosis, were not observed. The estimated integrated dose of external radiation in atrophic thyroids ranged from maximum 589 mSv to minimum 8 mSv. Immunohistochemical analysis of anti‐nitroguanosine and the TUNEL method in goiter and atrophic thyroid glands did not reveal any positive findings. The present study indicates that there was no significant relationship between a radiation effect and pathological findings in any thyroid glands. 相似文献
76.
Itaru Sato Jun Sasaki Hiroshi Satoh Masahiro Natsuhori Takahisa Murata Keiji Okada 《Animal Science Journal》2019,90(8):1090-1095
Blood and urine were compared to clarify which is a better sample for estimating the concentration of radioactive cesium in muscles of live cattle. The most probable concentration of 137Cs in muscles was 21.0 times that in blood, and the error of this estimation was 28%. The concentration of 137Cs in blood was estimated accurately using urine samples. The estimation error did not increase so much (33%), even when the concentration of 137Cs in muscles was estimated using urine samples. On the other hand, the maximum volume of blood that can be collected with one syringe is 50 ml, whereas it is easy to collect 1,000 ml of urine. It took at least 360 min to confirm that a cow meets the legal standard by inspecting 50 ml of blood. However, with 1,000 ml of urine, a 20 min measurement time was sufficient for this purpose. This difference in the required measurement time is critically important for practical use. In addition, urine can be collected by farmers themselves, whereas the blood collection requires a veterinarian. Therefore, urine is a more convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium. 相似文献
77.
Itaru Sato Jun Sasaki Hiroshi Satoh Yoshitaka Deguchi Hiroyuki Chida Masahiro Natsuhori Kumiko Otani Keiji Okada 《Animal Science Journal》2019,90(1):128-134
White blood cells, especially lymphocytes, are susceptible to radiation exposure. In the present study, red blood cell, total white blood cell, and lymphocyte counts were repeatedly measured in cattle living on three farms located in the “difficult‐to‐return zone” of the Fukushima nuclear accident, and compared with two control groups from unaffected areas. Blood cell counts differed significantly between the two control groups, although almost all the values fell within the normal range. The blood cell counts of the cattle in the “difficult‐to‐return zone” varied across sampling times even on the same farms, being sometimes higher or lower than either of the two control groups. However, neither a statistically significant decrease in blood cell counts nor an increase in the rate of cattle with extremely low blood cell counts was observed overall. The estimated cumulative exposure dose for the cattle on the most contaminated farm was within a range of 500–1000 mSv, exceeding the threshold for the lymphopenia. Because of the low dose rate on these farms, potential radiation damages would have been repaired and have not accumulated enough to cause deterministic effects. 相似文献
78.
Oxidative stress and bovine liver diseases: role of glutathione peroxidase and glucose 6-phosphate dehydrogenase 总被引:1,自引:0,他引:1
This article summarizes the different types of free radicals, antioxidants and the effect of oxidative stress on the activities of glutathione peroxidase and glucose 6-phosphate dehydrogenase in bovine liver diseases. A growing body of evidence suggests that the formation of reactive oxygen species is a common occurrence associated with most if not all disease processes. The overall importance of reactive oxygen species to the progression and severity of various disease states varies greatly depending on the conditions and whether the disease is acute or chronic. Free radical researches in animals are in progress and further investigations are needed to establish the involvement of reactive oxygen species in diseases affecting different animal species and the pathology they produce. 相似文献
79.
Go Suzuki Wataru Okada Youko Yasutake Sayaka Kai Yuji Fujikura Iwao Tanita Hiroshi Yamashita Takeshi Hayashibara Wataru Ando Koichi Nogami Masayuki Fudo 《Fisheries Science》2018,84(5):849-856
Extremely low post-settlement survival is one of the largest barriers for artificial rehabilitation of Acropora corals. However, little data have been found for interspecific difference of the post-settlement survival probably because the observation of coral juvenile is difficult in the field. Here, we analyzed the survival of three dominant species of Acropora corals (A. digitifera, A. tenuis, A. yongei), with different colony morphologies and habitat preferences, for 2 years after settlement under the same environmental conditions. The post-settlement survival was significantly higher for A. tenuis than for A. digitifera 3 months after settlement. Two years later, the survival rate of A. tenuis was approximately 15 times higher than A. digitifera. In a separate analysis of three bottle-brush species (A. awi, A. echinata, A. subglabra) and A. tenuis, post-settlement survival was always higher for A. awi than for other two bottle-brush species, suggesting that the initial survival was different among morphologically sister species. Low survival was possibly associated with slow growth rates during the first 7 months. Thus, species selection is important for successful artificial coral rehabilitation, with A. tenuis being the most viable option. Alternatively, new techniques are required to improve post-settlement survival of slow growing coral species. 相似文献
80.
First feeding of diploid and triploid yellowtail tetra Astyanax altiparanae: An initial stage for application in laboratory studies 下载免费PDF全文
Rafaela Manchin Bertolini José Augusto Senhorini Nivaldo Ferreira do Nascimento Matheus Pereira‐Santos Laura Satiko Okada Nakaghi Wellington Adriano Moreira Peres Regiane Cristina da Silva George Shigueki Yasui 《Aquaculture Research》2018,49(1):68-74
In this study, the aim was to establish a protocol for first feeding of diploid and triploid yellowtail tetra Astyanax altiparanae in laboratory conditions. The fry were fed with five different diets: (i) Artemia franciscana nauplii, (ii) plankton, (iii) dry food, (iv) Artemia franciscana nauplii + plankton, and (v) Artemia nauplii + plankton + dry food. Additionally, the growth and survival rates of diploid and triploid individuals were also evaluated. On day 10, the length of the fish between the treatments differed significantly (p = .0001) and ranged from 4.07 ± 0.06 mm (dry food) to 8.50 ± 0.64 mm (plankton + Artemia). The sizes of the fish increased with time, except for the fish fed with dry food. The survival rates were similar for the fish fed with the four diets and ranged from 80.7 ± 5.4% (dry food + plankton + Artemia to 92.0 ± 1.6% (plankton + Artemia), but differed from the fish fed with dry food (17.7 ± 5.8%, p = .0017). Diploids and triploids did not present differences on day 0 (p = .2252) and on day 10 (p = .4844) when the fish presented 6.77 ± 0.25 mm and 6.54 ± 0.15 mm respectively. Survival of diploids (87.3 ± 5.13%) and triploids (74.67 ± 2.30%) were also similar (p = .0285). These data are innovative and useful for establishing protocols for this species in both academic and applied sciences. 相似文献