全文获取类型
收费全文 | 163篇 |
免费 | 7篇 |
专业分类
林业 | 4篇 |
农学 | 2篇 |
16篇 | |
综合类 | 5篇 |
农作物 | 6篇 |
水产渔业 | 19篇 |
畜牧兽医 | 106篇 |
植物保护 | 12篇 |
出版年
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2013年 | 13篇 |
2012年 | 10篇 |
2011年 | 12篇 |
2010年 | 3篇 |
2009年 | 7篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 1篇 |
1999年 | 2篇 |
1992年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1960年 | 1篇 |
排序方式: 共有170条查询结果,搜索用时 296 毫秒
101.
High-resolution Greenland ice core data show abrupt climate change happens in few years 总被引:1,自引:0,他引:1
Steffensen JP Andersen KK Bigler M Clausen HB Dahl-Jensen D Fischer H Goto-Azuma K Hansson M Johnsen SJ Jouzel J Masson-Delmotte V Popp T Rasmussen SO Röthlisberger R Ruth U Stauffer B Siggaard-Andersen ML Sveinbjörnsdóttir AE Svensson A White JW 《Science (New York, N.Y.)》2008,321(5889):680-684
The last two abrupt warmings at the onset of our present warm interglacial period, interrupted by the Younger Dryas cooling event, were investigated at high temporal resolution from the North Greenland Ice Core Project ice core. The deuterium excess, a proxy of Greenland precipitation moisture source, switched mode within 1 to 3 years over these transitions and initiated a more gradual change (over 50 years) of the Greenland air temperature, as recorded by stable water isotopes. The onsets of both abrupt Greenland warmings were slightly preceded by decreasing Greenland dust deposition, reflecting the wetting of Asian deserts. A northern shift of the Intertropical Convergence Zone could be the trigger of these abrupt shifts of Northern Hemisphere atmospheric circulation, resulting in changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next. 相似文献
102.
Kanokwan SRIRATTANA Kazutsugu MATSUKAWA Satoshi AKAGI Mariko TASAI Takahiro TAGAMI Keijiro NIRASAWA Takashi NAGAI Yukio KANAI Rangsun PARNPAI Kumiko TAKEDA 《Animal Science Journal》2011,82(2):236-243
Although interspecies/intergeneric somatic cell nuclear transfer (iSCNT) has been proposed as a tool to produce offspring of endangered species, conflict between donor nucleus and recipient cytoplasm in iSCNT embryos has been identified as an impediment to implementation for agricultural production. To investigate the nuclear–mitochondrial interactions on the developmental potential of iSCNT embryos, we analyzed the mtDNA copy numbers in iSCNT embryos reconstructed with water buffalo (swamp type) fibroblasts and bovine enucleated oocytes (buffalo iSCNT). As controls, SCNT embryos were derived from bovine fibroblasts (bovine SCNT). Buffalo iSCNT and bovine SCNT embryos showed similar rates of cleavage and development to the 8‐cell stage (P > 0.05). However, buffalo iSCNT embryos did not develop beyond the 16‐cell stage. Both bovine and buffalo mtDNA content in buffalo iSCNT embryos was stable throughout the nuclear transfer process, and arrested at the 8‐ to 16‐cell stage (P > 0.05). In bovine SCNT embryos that developed to the blastocyst stage, mtDNA copy number was increased (P < 0.05). In conclusion, both the donor cell and recipient cytoplast mtDNAs of buffalo iSCNT embryos were identified and maintained through the iSCNT process until the 8–16‐cell stage. In addition, the copy number of mtDNA per embryo was a useful monitor to investigate nuclear–mitochondrial interactions. 相似文献
103.
104.
The effects of non-ionic (sorbitol, maltose, trehalose) and ionic compounds (Na-glutamate, Na-acetate, Na-sulfate, ammonium
sulfate) on freeze denaturation of myosin subfragment-1 (S-1) and of myofibrils were compared. Sugars, Na-glutamate and Na-acetate
well suppressed the freeze denaturation of myofibrils as well as S-1 in a concentration dependent manner. Although sulfate
suppressed freeze denaturation of S-1 irregularly, it accelerated myofibril denaturation. It was concluded that sulfate salts
were useless as cryoprotectant for myofibrils. Stabilization extent by F-actin in frozen storage was much less than that in
heating. 相似文献
105.
Yosuke Amagai Akane Tanaka Kyungsook Jung Akira Matsuda Kumiko Oida Sho Nishikawa Hyosun Jang Saori Ishizaka Hiroshi Matsuda 《Research in veterinary science》2014
Mast cell tumor (MCT) is the most common cutaneous tumor in dogs. We recently revealed that production of stem cell factor (SCF) contributes to the proliferation of neoplastic mast cells in an autocrine/paracrine manner. The aim of the present study was to determine the contribution of the mechanism in clinical MCTs. In consequence, high SCF expression (>10 times compared to HRMC cells) was observed in 5 of 7 MCT samples used in the study regardless of KIT mutation, which was confirmed in immunohistochemical analysis. In addition, production of SCF was observed in Ki-67-positive cells in the MCT xenograft. These results indicate the broad contribution of SCF autocrine/paracrine mechanism on clinical MCTs, providing the rationale for the clinical use of KIT inhibitors regardless of KIT mutation. 相似文献
106.
Kohei Matsushita Yuji Ishii Aki Kijima Shinji Takasu Ken Kuroda Hisayoshi Takagi Takehiko Nohmi Kumiko Ogawa Takashi Umemura 《Journal of toxicologic pathology》2021,34(1):23
Although gpt delta rats, as reporter gene-transgenic rats, were originally developed for in vivo mutation assays, they have also been used to evaluate chemical carcinogenesis and comprehensive toxicity. Therefore, it is necessary to accumulate background data on carcinogenicity and general toxicity in gpt delta rats. Here, we investigated the background data of 110-week-old male and female F344 gpt delta rats and wild-type rats. There was no effect of reporter gene transfection on animal survival rates and body weights during the experiment. The relative weight of male gpt delta rat adrenals was significantly higher than that of wild-type rats, possibly due to the higher incidence of pheochromocytoma. There were no intergenotype differences in the incidence of nonneoplastic lesions in both sexes, including chronic progressive nephropathy and focus of cellular alteration in the liver, which had a higher incidence in both genotypes. Additionally, the significantly higher incidence of adrenal pheochromocytoma in male gpt delta rats than that in wild-type rats was likely incidental because of the lack of differences in the incidences of preneoplastic (male and female) and neoplastic (female) adrenal lesions in both genotypes. Other neoplastic lesions in both sexes showed no intergenotype differences in incidence rates, although large granular lymphocytic leukemia in the spleen and Leydig cell tumors in the testes of males showed higher incidence rates. Overall, there were no effects of reporter gene transfection on the spectrum of spontaneous lesions in F344 gpt delta rats, thus supporting their applicability in evaluating chemical toxicity and carcinogenicity. 相似文献
107.
Morimoto M Tanimoto K Nakano S Ozaki T Nakano A Komai K 《Journal of agricultural and food chemistry》2003,51(2):389-393
The antifeedant polymethylated flavones 5-hydroxy-3,6,7,8,4'-heptamethoxyflavone, 5-hydroxy-3,6,7,8-tetramethoxyflavone, and 5,6-dihydroxy-3,7-dimethoxyflavone have been isolated from the cudweed, Gnaphalium affine D. Don (Compositae). These flavonoids and authentic analogues showed insect antifeedant activity against the common cutworm (Spodoptera litura F.). In a previous paper, it was suggested that there was no substituent on the B-ring of the flavonoid for the beneficial antifeedant activity against the common cutworm. These flavonoids having a phenyl group as the B-ring and the chromone as elimination of the B-ring from the flavonoids were used to test the hypothesis of the previously described B-ring effect. The known fact is that Sculletaria baicarensis (Rutaceae) produced the 2-phenyl flavone. Test compounds and their methylated derivatives were prepared from this material for the structure-activity relationship (SAR) study of insect antifeedant activity. In spite of the 2-phenyl flavonoids, some tested compounds did not show any insect antifeedant activity against the common cutworm, although these inactive flavonoids were deficient in the 6-substituent group on the A-ring of the flavonoid. This 6-position-substituted derivative almost showed strong insect antifeedant activity against common cutworm. Moreover, the tested flavonoids having a hydroxyl group as a substituent on any of the positions tended to increase the activity. These results suggested the importance of the 6-position substitution on the flavonoid; however, hydrophilic substituents decreased the activity. Baicalein (5,6,7-trihydroxyflavone) derivatives did not show any activity despite having the 6-substituent derivative. Although the activity of some chromones increased the activity of the flavone, the bulky B-ring was a disadvantage for the antifeedant activity. It was suggested that the charge on C(3) and C(5) of the flavonoid was important for the biological activity. Additionally, an adequate hydrogen bonding property, which is different from lipophilicity, was an advantage for the activity on the basis of a QSAR analysis. 相似文献
108.
109.
Chuan‐Zhao Wei Hiroshi Katoh Kumiko Nishimura Hideo Ishii 《Pest management science》2009,65(12):1344-1351
BACKGROUND: It is possible that a single nucleotide polymorphism (SNP) (G143A mutation) in the cytochrome b gene could confer resistance to quinone outside inhibiting (QoI) fungicides (strobilurins) in rice blast fungus because this mutation caused a high level of resistance to fungicides such as azoxystrobin in Pyricularia grisea Sacc. and other fungal plant pathogens. The aim of this study was to survey Magnaporthe oryzae B Couch sp. nov. isolates in Japan for resistance to QoIs, and to try to develop molecular detection methods for QoI resistance. RESULTS: A survey on the QoI resistance among M. oryzae isolates from rice was conducted in Japan. A total of 813 single‐spore isolates of M. oryzae were tested for their sensitivity to azoxystrobin using a mycelial growth test on PDA. QoI fungicide resistance was not found among these isolates. The introduction of G143A mutation into a plasmid containing the cytochrome b gene sequence of rice blast fungus was achieved by site‐directed mutagenesis. Molecular diagnostic methods were developed for identifying QoI resistance in rice blast fungus using the plasmid construct. CONCLUSION: As the management of rice blast disease is often dependent on chemicals, the rational design of control programmes requires a proper understanding of the fungicide resistance phenomenon in field populations of the pathogen. Mutation of the cytochrome b gene of rice blast fungus would be specifically detected from diseased leaves and seeds using the molecular methods developed in this study. Copyright © 2009 Society of Chemical Industry 相似文献