全文获取类型
收费全文 | 391篇 |
免费 | 6篇 |
专业分类
林业 | 59篇 |
农学 | 8篇 |
基础科学 | 1篇 |
48篇 | |
综合类 | 20篇 |
农作物 | 15篇 |
水产渔业 | 13篇 |
畜牧兽医 | 200篇 |
园艺 | 2篇 |
植物保护 | 31篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 26篇 |
2012年 | 18篇 |
2011年 | 33篇 |
2010年 | 11篇 |
2009年 | 21篇 |
2008年 | 27篇 |
2007年 | 29篇 |
2006年 | 25篇 |
2005年 | 23篇 |
2004年 | 20篇 |
2003年 | 25篇 |
2002年 | 23篇 |
2001年 | 13篇 |
2000年 | 15篇 |
1999年 | 9篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有397条查询结果,搜索用时 31 毫秒
81.
Poly ion complexes of anionic lignosulfonic acid (LSA) with cationic poly(2-vinyl pyridine) or poly(4-vinyl pyridine) were
prepared by mixing the polymer solutions in dimethyl sulfoxide or dilute hydrochloric acid. The complexes were formed as soon
as the polymer solutions were mixed. Fourier transform infrared (FTIR) measurements for the complexes revealed the presence
of strong ionic interactions between sulfonate anions of LSA and pyridinium cations of the vinyl pyridine (VPy) polymers.
The strong interaction was supported by detection of a glass transition temperature (T
g) much higher than pristine T
g values of VPy polymers in differential scanning calorimetry. By using the ionic complexation, a coating of LSA onto VPy polymer
films was undertaken to modify their original surface property. Formation of a thin complex film was confirmed by observation
of absorption bands that are characteristic of the pyridinium cation in reflection FTIR spectra measurements, and by visualization
of the attached LSA component in atomic force microscopy. This treatment resulted in the surface of the VPy polymer films
becoming hydrophobic. An adhesion test was also conducted by pasting two veneered woods with the polymer complex, followed
by shear-tearing them off. The adhesive strength of the complex was estimated to be 1.1 MPa.
Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan
Wood Research Society 相似文献
82.
Nakagawa T Watanabe M Ohashi E Uyama R Takauji S Mochizuki M Nishimura R Ogawa H Sugano S Sasaki N 《Research in veterinary science》2006,80(3):317-323
We characterised cultured canine mammary gland adenocarcinoma cells by exhaustive step protein expression analysis to identify factors associated with tumour progression or metastasis of canine mammary gland tumour. Cultured adenocarcinoma cells derived from a total of 3 primary and 3 metastatic lesions from 3 dogs (CHMp/m, CIPp/m and CNMp/m, where CHM, CIP, and CNM indicate the 3 animals) were used in this study. The expression of 24 proteins reported to be related to tumourigenesis or malignancy of human breast cancers were examined by Western blot analysis using 24 antibodies. The expression of sialyl Lewis X [sLe(x)] was only observed in CHMm cells, which were derived from pleural effusion. This expression was further confirmed by immunohistochemistry. The levels of some factors, such as 14-3-3sigma, cyclinD1 and Rb, differed among cells or between the primary and metastatic cells in the pair. Though the difference in their expression was not consistent within the cells from primary and metastatic origin, this characterisation should provide useful information for further molecular analysis of these cultured cells. Since some of the factors, such as sLe(x), 14-3-3sigma, cyclinD1 and Rb, showed different levels of expression in the pair, these cultured cells might be meaningful tools for clarification of distant metastasis in canine mammary gland tumours. 相似文献
83.
Kazuki TAKAHASHI Yasuyuki KANEKO Akiko SHIBANAI Shushi YAMAMOTO Ayana KATAGIRI Tatsuyuki OSUGA Yoshiyuki INOUE Kohei KURODA Mika TANABE Tamaki OKABAYASHI Kiyokazu NAGANOBU Isao MINOBE Akatsuki SAITO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(5):648
The hepatitis B virus (Hepadnaviridae) induces chronic hepatitis and hepatic cancer in humans. A novel domestic cat hepadnavirus (DCH) was recently identified in several countries, however, the DCH infection status of cats in Japan is unknown. Therefore, we investigated the DCH infection rate of 139 cat samples collected in Japan. We identified one positive blood sample (0.78%) from a 17-year-old female cat with chronically elevated alanine aminotransferase. Phylogenetic analysis demonstrated that the DCH strain identified in this study is genetically different from strains in other countries. Further investigations are required to elucidate the evolution of DCH and the impact of DCH infection on hepatic diseases in domestic cats. 相似文献
84.
Naoya KAWAHARA Yoshiyuki TSUCHIYA Natsumi ENDO Tomomi TANAKA 《The Journal of reproduction and development》2023,69(1):41
To improve the accuracy of ultrasonographic assessment of luteal function, we investigated the relationship between ovarian ultrasonographic findings on Day 7 (Day 1 = ovulation) and plasma progesterone (P4) concentration, nutritional metabolic factors, and pregnancy outcome. A total of 47 spontaneous estrus events were investigated in 38 lactating Holstein cows (artificial insemination, n = 31; embryo transfer, n = 16). Transrectal ultrasonography was performed on Days 0 and 7 to measure the pre-ovulatory follicle area on Day 0 and the luteal tissue area (LTA), luteal blood flow area (LBF), relative LBF (rLBF) (= LBF/LTA), and dominant follicle area (DFA) on Day 7. Blood samples were collected on Day 7 to measure plasma P4, insulin-like growth factor-I (IGF-I), insulin, and metabolites. Plasma P4 concentration was positively correlated with LTA but was not associated with LBF or rLBF. Plasma P4 concentration was positively correlated with blood glucose and IGF-I and negatively correlated with blood urea nitrogen and free fatty acid, and no significant relationship was found between the ultrasonographic findings of the corpus luteum (CL) and these blood metabolites. Pregnant cows had smaller DFA than non-pregnant cows. In conclusion, LTA measurement can help predict plasma P4 concentration, but it was difficult to detect variations in plasma P4 concentration in relation to changes in energy status by evaluating the CL ultrasonographically. A combined assessment of CL and first-wave dominant follicle may be important in evaluating fertility. 相似文献
85.
Fumiko TAGUCHI Rui TANAKA Sayuri KINOSHITA Yuki ICHINOSE Yoshiyuki IMURA Salamah ANDI Kazuhiro TOYODA Tomonori SHIRAISHI Tetsuji YAMADA 《Journal of General Plant Pathology》2001,67(2):116-123
To elucidate the role of harpins produced by Pseudomonas syringae, the corresponding hrpZ gene was isolated from P. s. pv. tabaci. The sequence information revealed that this gene carries a serious mutation with 326 bp lacking in the central region and
potentially encodes only 140 N-terminal amino acids because of a frame shift. The investigation of biological properties using
recombinant harpin indicated harpinpsta was incapable of inducing HR in both host and nonhost plants. Based on an immunoblot analysis to detect harpin from P. s. pathovars in hrp-inducing medium, the truncated harpinpsta was neither expressed nor secreted into the culture medium. These results suggest that harpin is not the sole determinant
of the host-parasite specificity in P. s. pv. tabaci.
Received 10 August 2000/ Accepted in revised form 21 December 2000 相似文献
86.
Yoshiyuki Kiyono Yukihito Ochiai Yukihiro Chiba Hidetoshi Asai Kazuki Saito Tatsuhiko Shiraiwa Takeshi Horie Visone Songnoukhai Viengmany Navongxai Yoshio Inoue 《Journal of Forest Research》2007,12(5):371-383
In northern Lao People’s Democratic Republic, rising human population has drastically reduced the fallow period of slash-and-burn
agriculture which has led to a considerable decrease in the carbon stock in these communities. We estimated chronosequential
changes in the communities' carbon stocks, and established the relationship between the fallow period and fallow-period-average
carbon stocks in three carbon pools of bamboo-dominated communities in hilly areas of the Luang Prabang Province, northern
Lao People’s Democratic Republic. Based on measurements by destructive sampling, we devised a model and root-to-shoot ratios
for estimating bamboo biomass. In six secondary plant communities established after slash-and-burn cropping, we estimated
community biomass using the above model and others, and measured deadwood and litter stocks. The communities’ biomass and
deadwood significantly increased with time after the last cropping and the former reached about 100 Mg ha−1 after 15 years, whereas litter stocks did not show significant trends over time. Extending the fallow period from 2 to 5 years
would increase fallow-period-average carbon stock from 14.2 to 25.1 Mg C ha−1. The overstory height was significantly correlated with biomass, deadwood, and litter carbon stocks of these communities.
Based on our findings, changes in a community’s carbon stocks can be estimated using the changes in overstory height, which
should be taken into account in future studies to reduce uncertainty in estimating carbon stocks in tropical ecosystems. 相似文献
87.
Hideo Ohashi Tetsuya Kyogoku Takahiro Ishikawa Shin-ichiro Kawase Shingo Kawai 《Journal of Wood Science》1999,45(1):53-63
The present work was undertaken from the standpoint of radical-capturing ability with regard to the antioxidative ability of flavonoids, especially flavonols distributed widely in woody plants. In regard to the flavonols, six methyl derivatives were initially prepared from quercetin and its litinoside. Their radical-capturing constants were determined strictly by the stopped-flow spectroscopic method. It was proved that the radical-capturing ability of quercetin mainly involves the vicinal C3. and C4, hydroxyl groups and the C3 hydroxyl group. To clarify the reaction mechanism begun at the C3 hydroxyl group of quercetin, 5,7,3,4-tetramethylquercetin (TMQ), flavon-3-ol (F30) and so on were treated with 2,2-azo-bis-(2,4-dimethylvaleronitrile) (AMVN). Six products (1–6) containing one depside and its two hydrolytic products, two valeronitrile adducts, and others were isolated from the reaction mixture of TMQ and their structures determined by instrumental analyses. Similarly, F30 gave four products, 7–10, which corresponded to the above products 1–3 and 5 (one depside, its two hydrolytic products, and one adduct), respectively. 3,5,7,3,4-Pentamethylquercetin (PMQ) and flavon-3-O-methylate (F3M) gave no products. The quantitative change of the products with reaction time was determined spectroscopically. An initial reaction pathway for the radical-capturing reaction of flavon-3-ols with AMVN was proposed based on the products and their amounts. The main route — formation of depside and its hydrolytic products via ketohydroperoxide (3) or ketohydroperoxy radical (4) - was similar to that of the oxidation reaction of quercetin with quercetinase and light.Part of this paper was presented at the 46th and 47th annual meetings of the Japan Wood Research Society, Kumamoto and Kouchi, April 1996 and 1997 相似文献
88.
Mariko Yoshioka Keiji Takabe Junji Sugiyama Yoshiyuki Nishio 《Journal of Wood Science》2006,52(2):121-127
New biodegradable cellulose acetate/layered silicate grafted poly(ε-caprolactone) [(CA/layered silicate)-g-PCL] nanocomposites were prepared by in situ polymerization of ε-caprolactone in the presence of cellulose acetate (CA) and organically modified layered silicate (OMLS). The structures of
the resulting composites were investigated. X-ray diffractometry was carried out to survey general structural features of
(CA/OMLS)-g-PCL nanocomposites, and revealed that OMLSs having hydroxyl groups in the organic modifiers greatly altered the layered silicate
structure by monomer intercalation and successive exfoliation through its polymerization. Two of the representative cases
were characterized by wide-angle and small-angle X-ray scattering analyses with a synchrotron source. The morphology of these
nanocomposites was further examined by transmission electron microscopy. When SPN, one of OMLSs having one hydroxyl group
in its modifier, was used, the silicate layers could not be dispersed thoroughly, but existed as aggregates consisting of
several silicate layers. Among them, the crystal growth of PCL developed by transcrystallization, where the crystal growth
was restricted in the confined space. When Cloisite 30B, having two hydroxyl groups within the modifier, was used, the silicate
layers forming the clay were dispersed completely in the composite and random orientation of the OMLS was observed. 相似文献
89.
Shingo Kawai Yosuke Kobayashi Makoto Nakagawa Hideo Ohashi 《Journal of Wood Science》2006,52(4):363-366
Nonphenolic β-O-4 lignin substructure model dimer, 1,3-dihydroxy-2-(2,6-dimethoxyphenoxy)-1-(4-ethoxy-3-methoxyphenyl)propane (I) was degraded by horseradish peroxidase (HRP) in the presence of hydrogen peroxide and 1-hydroxybenztriazole (HBT). 4-Ethoxy-3-methoxybenzoic
acid (II), 1-(4-ethoxy-3-methoxyphenyl)-3-hydroxypropanone (III), 2,3-dihydroxy-1-(4-ethoxy-3-methoxyphenyl)-1-formyloxypropane (IV), 2,3-dihydroxy-1-(4-ethoxy-3-methoxyphenyl)propanone (V), 1-(4-ethoxy-3-methoxyphenyl)-1,2,3-trihydroxypropane (VI), 1-(4-ethoxy-3-methoxyphenyl)-1,2,3-trihydroxypropane-2,3-cyclic carbonate (VII), and 1-(4-ethoxy-3-methoxyphenyl)-1,2,3-trihydroxypropane-1,2-cyclic carbonate (VIII) were identified as degradation products by gas chromatography-mass spectrometry. These degradation products were qualitatively
the same as those of substrate I in the laccase/HBT system, but the yield of the products was apparently different. The products catalyzed by the HRP/H2O2/HBT system contained large amounts of the aromatic ring cleavage products IV, VII, and VIII compared with those catalyzed by the laccase/HBT system, while the amount of Cα-Cβ cleavage product II is relatively low. These results suggest that the role of HBT is not in a simple one-electron transfer between the enzymes
and substrates. 相似文献
90.
Effects of age, egg-laying activity, and Salmonella-inoculation on the expressions of gallinacin mRNA in the vagina of the hen oviduct 总被引:1,自引:0,他引:1
Yoshimura Y Ohashi H Subedi K Nishibori M Isobe N 《The Journal of reproduction and development》2006,52(2):211-218
Gallinacins (Gal) are antimicrobial peptides that play significant roles in innate immunity in chickens. The aim of this study was to examine whether age of birds and egg-laying activity (laying and non-laying caused by feed-regulation) affect the mRNA expression of Gal-1, -2, and -3 in the vagina of hens, and whether their expressions are changed in response to the stimulation with Salmonella enteritidis (SE) and lipopolysaccharide (LPS). White Leghorn hens were divided into groups of young and old laying hens, and groups of laying and non-laying hens after feed-regulation. Vaginal cells were cultured and stimulated with SE or LPS. Expressions of Gal-1, -2, and -3 mRNA in their vaginal mucosa and cultured cells were examined by quantitative real-time RT-PCR. The expressions of Gal-1, -2, and -3 of the vaginal mucosa were significantly greater in old birds than in young birds. Expression of these Gals in the vagina were decreased in the regressed oviduct of non-laying birds compared with laying birds. The expressions of Gal-1, -2, and -3 in the cultured vaginal cells were increased by stimulation with SE or LPS within 24 h. These results suggest that the mRNA expressions of Gal-1, -2 and -3 in the vagina of laying hens increased with age, whereas they decreased in the regressed oviduct during the non-laying phase. Also, synthesis of these antimicrobial peptides in the vagina may increase in response to SE and LPS to eliminate SE bacteria. 相似文献