全文获取类型
收费全文 | 221篇 |
免费 | 13篇 |
国内免费 | 2篇 |
专业分类
林业 | 18篇 |
农学 | 3篇 |
基础科学 | 1篇 |
35篇 | |
综合类 | 7篇 |
农作物 | 9篇 |
水产渔业 | 31篇 |
畜牧兽医 | 124篇 |
植物保护 | 8篇 |
出版年
2023年 | 1篇 |
2022年 | 12篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 5篇 |
2011年 | 11篇 |
2010年 | 5篇 |
2009年 | 18篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 16篇 |
2003年 | 10篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有236条查询结果,搜索用时 15 毫秒
41.
The purpose of this study was to clarify the effect of decreased food consumption on evaluation of myelotoxicity in routine general toxicity studies. Male rats were divided into the following 7 groups: 12, 15, and 18 mg/kg 5-fluorouracil (5-FU) treatment groups (FU12, FU15 and FU18); dietary restriction groups (R12, R15 and R18 receiving the same amount of food as the rats in the FU12, FU15 and FU18 groups, respectively); and a nontreated control group (NT). We compared the changes in body weight, hematology and the results of cytological analyses of bone marrow and histopathology among the groups after administration and recovery periods of 14 and 7 days, respectively. At the end of the administration period, the FU15 and FU18 groups showed decreases in many hematologic and bone marrow parameters that were all similar to those in the corresponding dietary restriction groups (R15 and R18). A granulocyte abnormality (polyploidy: frequency of 1% or less) was also observed in all 5-FU treated groups. At the end of the recovery period, increases in the reticulocyte and platelet counts and extramedullary hematopoiesis of the spleen were observed in the 5-FU treated groups. These results indicate that the results of general toxicity studies in rats should be evaluated in consideration of dietary restriction effects when food consumption is decreased at about 30-40% or more. Careful morphological observation of hemocytes would be helpful in distinguishing the effect of a drug from that of dietary restriction in relation to hematological and bone marrow parameters. Performance of a recovery test to determine the reactive response of hematopoiesis is also recommended. 相似文献
42.
43.
44.
Hideki TAKAHASHI Mitsuhiro SUGIYAMA SUKAMTO Akira KARASAWA Shuu HASE Yoshio EHARA 《Journal of General Plant Pathology》2000,66(4):335-344
A variant of Cucumber mosaic virus, CMV(Y/GM2), was isolated from a tobacco plant with mild green mosaic symptoms that was regenerated in vitro from a yellow strain of CMV [CMV(Y)]-infected tobacco leaves by tissue culture. CMV(Y/GM2) has two amino acid substitutions
at 36 and 111 positions in the coat protein encoded on RNA3. CMV, assembled by mixing in vitro transcribed CMV(Y) RNA1 and RNA2 plus infectious RNA3 transcribed in vitro from cDNA to RNA3 of CMV(Y/GM2), was prepared and designated as CMV(Y/GM2)tr. When tobacco (Nicotiana tabacum cv. Xanthi nc) plants were inoculated with CMV(Y/GM2)tr, large necrotic local lesions in which the virus was localized, developed
on the inoculated leaves. This host response unique to CMV(Y/GM2)tr was similar to the hypersensitive response (HR), which
is a common resistance response to avirulent pathogens and was observed in five cultivars of Nicotiana tabacum and eight Nicotiana species. The revertant virus, however, accumulated to quite different levels in the various hosts. CMV(Y/GM2)tr induced pathogenesis-related
1 (PR-1) protein accumulation and systemic acquired resistance (SAR) which were generally observed in the HR. However, when
tobaccos were inoculated with CMV(S36P)tr and CMV(V111I)tr, which have an amino acid substitution at either the 36 or 111
position in the coat protein of CMV(Y), respectively, CMV(S36P)tr was restricted to the primary infection site without necrotic
local lesion formation and PR-1 protein and SAR induction. CMV(V111I)tr, however, systemically spread and induced mild green
mosaic symptoms, while the host had the HR to CMV(Y/GM2)tr. The localization of CMV(Y/GM2)tr at the primary infection site
may not only be caused by the HR, but also by the restriction of virus systemic movement resulting from the amino acid substitution
at position 36 in the coat protein of CMV(Y).
Received 15 December 1999/ Accepted in revised form 18 April 2000 相似文献
45.
Sawai Y Satake K Kamataki T Nasu H Shishikura M Atwater BF Horton BP Kelsey HM Nagumo T Yamaguchi M 《Science (New York, N.Y.)》2004,306(5703):1918-1920
In eastern Hokkaido, 60 to 80 kilometers above a subducting oceanic plate, tidal mudflats changed into freshwater forests during the first decades after a 17th-century tsunami. The mudflats gradually rose by a meter, as judged from fossil diatom assemblages. Both the tsunami and the ensuing uplift exceeded any in the region's 200 years of written history, and both resulted from a shallow plate-boundary earthquake of unusually large size along the Kuril subduction zone. This earthquake probably induced more creep farther down the plate boundary than did any of the region's historical events. 相似文献
46.
47.
Yuma SAHASHI Masaaki OSHIMA Junjiro YAMAGISHI Chieko MURAMATSU Kaori SHIMIZU Yasuo INOSHIMA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(11):1730
Polymerase chain reaction (PCR) combined with restriction fragment length polymorphism (RFLP) is commonly used for genotyping bovine leukemia virus (BLV) in slaughterhouses. However, unclassified BLV genotypes have been sporadically reported. To assess the current status of BLV genetic characterization in cattle, PCR-RFLP was performed on blood samples of 170 cattle (84 Japanese Black, 60 Japanese Black x Holstein, and 26 Holstein) from 17 farms (5 prefectures) at a slaughterhouse in Aichi Prefecture in 2019. A total of 65 samples (38.2%) were BLV positive, and genotype 1 was the most predominant (56/65 samples), followed by genotypes 3 (6 samples) and 5 (1 sample), and two unclassified samples. No relationship between the genotypes and breeds was observed. Sequence and phylogenetic analyses demonstrated that unclassified BLV genotypes clustered with genotype 1 sequences were, therefore, not new genotypes. 相似文献
48.
A neural network system with genetic algorithms (Neurogenetic Algorithm System, or NGAS) was employed to develop individual
coniferous tree growth models. A multivariable regression model was applied to compare the performance of NGAS. An IBM personal
computer with the BioComp System’s software program of NGO was used to execute this comparison. The results indicate that
NGAS is more accurate and effective than the conventional regression method in modeling individual tree growth based on the
criteria of Sum of Squared Error (SSE), Average Absolute Error (AAE), Mean Squared Error (MSE) and Final Predicted Error (FPE).
This study also suggests that individual tree growth may indeed be a non-linear process. Using this flexible neural network
system to model individual tree growth can yield satisfactory prediction results. 相似文献
49.
Jun’ichiro Ide Tomonori Kume Yoshifumi Wakiyama Naoko Higashi Masaaki Chiwa Kyoichi Otsuki 《Forest Ecology and Management》2009
Japanese cypress (Chamaecyparis obtusa) is one of the most common plantation species in Japan. In most Japanese cypress plantations, closure of the forest canopy hinders understory growth because of insufficient management practices. Thus leaf litter barely covers the soil surface. Such plantations are vulnerable to surface erosion triggered by rainfalls, and could yield large amounts of suspended sediment (SS). However, few studies have investigated the annual SS yield. This study aimed to develop a modified model of SS yields, and to accurately estimate and characterize the annual SS yield from a Japanese cypress plantation. For this, hydrological surveys were conducted for 5 years, and stream water was sampled weekly as well as sequentially at 15–60 min intervals in each of 14 rain events in a small forested watershed of Japanese cypress. The root mean square error (RMSE) and the annual SS yield estimates were obtained using three different equations: the rating curve derived from instantaneous SS concentration versus stream discharge relationship (SSC − Q equation); the rating curve derived from cumulative SS yield versus cumulative specific discharge relationship (∑SS − ∑Q equation); and the multiple regression of cumulative SS yield expressed as functions of cumulative specific discharge and antecedent rainfalls (∑SS − ∑Q × AR equation). The ∑SS − ∑Q × AR equation is a modified model considering the effects of antecedent rain history on the SS yield. The parameters in each equation were determined by a nonlinear least square method. Of the three equations, the RMSE was the highest using the SSC − Q equation. Although the ∑SS − ∑Q equation and the ∑SS − ∑Q × AR equation gave similar RMSE values, the SS yields extrapolated by the ∑SS − ∑Q equation would be overestimated. Thus, the 5-year average of annual SS yield estimated by the ∑SS − ∑Q equation was three times larger than that estimated by the ∑SS − ∑Q × AR equation. These results indicate that the ∑SS − ∑Q × AR equation more accurately estimates the annual SS yield, compared with the other two equations. The results also suggest that antecedent rain history, as well as stream discharge, should be considered for appropriately estimating the annual SS yield. The annual SS yield estimated by the ∑SS − ∑Q × AR equation was the largest among 25 undisturbed forested watersheds, except for two watersheds dominated by sandstone. Our results suggest that the annual SS yield is greater from a Japanese cypress plantation under current management practices than from other undisturbed forests. 相似文献
50.
Kazunori KATAYAMA Makoto TOMATSU Hidetaka FUCHU Masaaki SUGIYAMA Satoshi KAWAHARA Kiyoshi YAMAUCHI Yukio KAWAMURA Michio MUGURUMA 《Animal Science Journal》2003,74(1):53-58
To search for a novel angiotensin I‐converting enzyme (ACE) inhibitory peptide, porcine skeletal troponin was hydrolyzed with pepsin. This hydrolysate showed ACE inhibitory activity, and was applied to various kinds of chromatography to separate an active peptide. Analysis using a protein sequencer identified this peptide as RMLGQTPTK (9mer). This sequence was estimated to occur at the 44–52 position of troponin C, and its 50% inhibitory protein concentration (IC50) was 34 µM. RMLGQTP (7mer), a partial peptide of 9mer, showed activity with an IC50 of 503 µM. RP‐HPLC analysis of a reaction mixture of 9mer and ACE showed that 9mer was slowly hydrolyzed by ACE. On the other hand, 7mer was rapidly hydrolyzed by ACE. Activity of 9mer was reduced as its hydrolysis by ACE proceeded. To estimate the resistance of 9mer to digestive proteases after oral administration, it was reacted with pepsin, α‐chymotrypsin, or trypsin. In each of these reaction mixtures, a significant amount of 9mer remained as a substrate after digestion. Remaining ACE inhibitory activity was close to that of 9mer. These results suggest that 9mer might not be digested after oral administration, because of its relatively high resistance to digestive proteases. Therefore, 9mer might be expected to work well in vivo as an ACE inhibitor. 相似文献