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排序方式: 共有117条查询结果,搜索用时 15 毫秒
91.
Suchanit Ngamkala Kunihiko Futami Masato Endo Masashi Maita Takayuki Katagiri 《Fisheries Science》2010,76(5):833-840
The present study histologically examined the effects of glucan-containing and Lactobacillus rhamnosus GG (LGG)-containing diets on intestinal damages inflicted on Nile tilapia by Aeromonas challenges. Tilapia were fed control, glucan, and LGG diets for 2 weeks and were subsequently challenged with Aeromonas. The intestines were then histologically examined at 1, 7, 14, and 21 days post-infection. Mortality following the challenge
was lower for the fish fed the glucan and LGG diets. The intestines of these groups also showed increased inflammatory cell
infiltration and reduced intestinal damage from Aeromonas. Moreover, inflammatory cell infiltration occurred more rapidly in the glucan-fed than in the LGG-fed fish following the
challenge. Before the challenge, the dominant mucous cell was the acid type in all the tests. After the challenge, the main
mucus cell type in the proximal intestine of the glucan-fed fish shifted to AB-PAS double-staining cells, while in the LGG-fed
fish, it remained the acid type throughout the test period, and the number of double-staining cells was smaller than in the
control fish after the challenge. Thus, the different mucous cell and inflammatory cell responses show that glucan and LGG
might have different immunostimulative effects, although they both reduced the intestinal damage following Aeromonas challenges. 相似文献
92.
Three types of proteinases, namely cysteine, metallo, and serine proteinases, were found in squid hepatopancreas by studying
the inhibition spectra using carp myofibril as substrate. The cysteine, metallo, and serine types showed the highest activities
at 50, 35, and 40°C, respectively. The optimal pHs were 5, 7, and 9 for the cysteine, metallo, and serine types, respectively.
When assayed at 20°C and pH 7.5, the metallo type showed the highest activity. The metallo type was characterized by a high
selectivity in the digestion of myosin. Among the three enzymes, the cysteine type was found to be the most stable against
thermal and acid treatments. Heat-treated myofibrils were more susceptible to the cysteine and serine types, but less susceptible
to the metallo type. Acid treatment of myofibrils also enhanced the digestibility by the cysteine type. The results indicated
that the cysteine type seemed to be the most suitable enzyme to produce peptides from denatured myofibrils by their random
digestion. 相似文献
93.
The suppressive effects of Ca2+ on the thermal denaturation of myosin and myofibrils of squid mantle muscle were compared. The stabilization effect on myosin
was smaller than that on myofibrils and was not affected by KCl concentration. The stabilizing effect of Ca2+ on myosin decreased as the heating temperature dropped, showing no stabilization at 20°C, while the effect on myofibrils
was the same at all temperatures tested. The stabilizing effect of Ca2+ on myosin disappeared even at 30°C in the presence of sorbitol, where a small inactivation rate was found, while the effect
of Ca2+ on myofibrils was equally detected irrespective of the reduction in inactivation rate in the presence of sorbitol. Stabilization
of myosin by Ca2+ again appeared even in the presence of sorbitol when the heating temperature was raised to 38°C. It was suggested that Ca2+ confers stabilization on myosin only when myosin is under unstable conditions. The stabilization effect of Ca2+ on myosin was enhanced upon F-actin binding: Ca2+-bound myosin was more significantly stabilized by F-actin binding, and the effect was no longer affected by the conditions
for heating. 相似文献
94.
Soil erosion by water is a common environmental problem which can affect the sustainable development and the agriculture of
developing countries especially. Therefore, several countries, threatened by this phenomenon, adopt different measures to
preserve and protect their natural resources. The main purpose of this study was to identify vulnerable areas to establish
a soil erosion risk map in Tunisia. In order to do so, an approach based on a combination of the Revised Universal Soil Loss
Equation (RUSLE) as an erosion model, Geographic Information System (GIS) and Remote Sensing was applied. RUSLE, which is
a model to predict soil loss, is composed of five factors. Erosivity factor (R factor), erodibility factor (K factor), topography factor (LS factor), crop management factor (C factor), and supporting practices factor (P factor). Furthermore, in order to get the most accurate C factor for each land use, times series Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation index (MODIS-EVI)
were used. MODIS-EVI time series was helpful for distinguishing vegetation dynamics with taking into account phenological
variation of the crops. The results indicated that Tunisia has a serious risk of soil erosion. Indeed, about 24.57% of our
study area had a soil loss rate more than 30 t/ha. In these areas, suitable and urgent measures and treatments should be required.
Finally, this approach which is based on remote sensing techniques, GIS and erosion model can be useful for planning appropriate
environmental decision-making policy in a global scale. 相似文献
95.
Ovarian immature oocytes accumulate many dormant maternal mRNAs, which have short poly(A) tails. Cytoplasmic‐polyadenylation‐element binding protein (CPEB) has been reported to play key roles for the elongation of the tails and the translation of these mRNAs in Xenopus oocytes. However, the functions of CPEB in meiotic resumption have not yet been established in mammalian oocytes. The present study examined the roles of porcine CPEB in Cyclin B syntheses and meiotic resumption of porcine oocytes. Porcine CPEB1 (pCPEB1) cDNA was cloned from total RNA of immature oocytes by RT‐PCR. The overexpression of pCPEB1 by mRNA injection into immature oocytes increased Cyclin B expression and the rate of meiotic resumption. Conversely, the inhibition of endogenous CPEB by expression of a dominant‐negative mutant pCPEB1 (AA‐CPEB), which replaced the expected phosphorylation sites with alanines, had the effect of inhibiting Cyclin B synthesis, ribosomal S6 kinase phosphorylation (an indicator of Mos activity), and meiotic resumption. The inhibition of porcine Aurora A by an injection of antisense RNA enhanced the inhibitory effects of AA‐CPEB. These results suggest the involvement of mammalian CPEB1 in Cyclin B syntheses and meiotic resumption in mammalian oocytes. In addition, the phosphorylation sites of pCPEB1 were identified and are suggested to be phosphorylated by porcine Aurora A. 相似文献
96.
Yoshimichi Fukuta Kunihiko Konisho Sachiko Senoo-Namai Seiji Yanagihara Hiroshi Tsunematsu Ayumi Fukuo Takashi Kumashiro 《Breeding Science》2012,62(1):27-37
A total of 18 rainfed upland New Rice for Africa (NERICA) varieties were categorized as the heavy panicle and low tillering types and early heading, in compared with 32 different varieties. These chromosome components were clarified using 243 SSR markers which showed polymorphism among NERICA varieties and their parents, CG 14 (O. glaberrima Steud.) and one of the recurrent parents, WAB-56-104 (O. sativa L.). NERICA varieties were classified into three groups, which corresponded with these parents’ continuation including two exceptions, NERICAs 14 and 17, by a cluster analysis using polymorphism data of SSR markers and 14 differential markers among them were selected to classify NERICA varieties. However, three groups: NERICAs, 3 and 4, NERICAs, 8, 9 and 11 and NERICAs, 15 and 16 were not distinguishable. Association analysis was carried out for characterization of NERICA varieties by using SSR markers genotype and phenotype of agronomic traits. A total of 131 quantitative trait loci between SSR markers and 11 agronomic traits were detected. The characteristics of early maturity and heavy panicle of upland NERICA varieties were succeeded from Asian rice varieties and the characteristics of high dry matter production and late heading were introduced from CG 14 and the other varieties. 相似文献
97.
98.
A novel bacterial strain FJ1117YT was isolated from an enrichment culture with the herbicide simetryn. The isolate was capable of degrading the herbicide supplied as the sole sulfur source in an aquatic batch culture. The strain FJ1117YT was identified as that belonging to Rhodococcus sp. on the basis of comparative morphology, physiological characteristics and comparison of the 16S rRNA gene sequence. The biodegradation pathway of simetryn was established by isolating the methylsulfinyl analogue as the first metabolite and by identification of the methylsulfonyl intermediate and the hydroxy analogue by liquid chromatography-mass spectrometry (LC-MS) and/or nuclear magnetic resonance (NMR) analysis. The results indicate that the methylthio group was progressively oxidised and hydrolysed by the strain FJ1117YT. The same strain is also able to metabolise other methylthio-s-triazines such as ametryn, desmetryn, dimethametryn and prometryn through similar pathways. 相似文献
99.
A moderately persistent herbicide, simazine, has been used globally and detected as a contaminant in soil and water. The authors have isolated a simazine-degrading bacterium from a simazine-degrading bacterial consortium that was enriched using charcoal as a microhabitat. The isolate, strain CDB21, was gram-negative, rod-shaped (0.5-0.6 microm x 1.0-1.2 microm) and motile by means of a single polar flagellum. Based on 16S rRNA sequence analysis, strain CDB21 was identified as a novel beta-proteobacterium exhibiting 100% sequence identity with the uncultured bacterium HOClCi25 (GenBank accession number AY328574). PCR using primers that were specific for the genes of the atrazine-degrading enzymes (atzABCDEF) of Pseudomonas sp. strain ADP showed that strain CDB21 also possessed the entire set of genes of these enzymes. Nucleotide sequences of the atzCDEF genes of strain CDB21 were 100% identical to those of Pseudomonas sp. strain ADP. Sequence identity of the atzA genes between these bacteria was 99.7%. The 398-nucleotide upstream fragment of the atzB gene of strain CDB21 was 100% identical to ORF30 of Pseudomonas sp. strain ADP, and the 1526-nucleotide downstream fragment showed 99.8% sequence similarity to the atzB gene of the pseudomonad. 相似文献
100.