全文获取类型
收费全文 | 1282篇 |
免费 | 49篇 |
国内免费 | 4篇 |
专业分类
林业 | 116篇 |
农学 | 29篇 |
158篇 | |
综合类 | 67篇 |
农作物 | 43篇 |
水产渔业 | 184篇 |
畜牧兽医 | 647篇 |
园艺 | 10篇 |
植物保护 | 81篇 |
出版年
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 34篇 |
2020年 | 24篇 |
2019年 | 27篇 |
2018年 | 28篇 |
2017年 | 27篇 |
2016年 | 40篇 |
2015年 | 29篇 |
2014年 | 39篇 |
2013年 | 71篇 |
2012年 | 59篇 |
2011年 | 69篇 |
2010年 | 35篇 |
2009年 | 40篇 |
2008年 | 73篇 |
2007年 | 63篇 |
2006年 | 61篇 |
2005年 | 56篇 |
2004年 | 55篇 |
2003年 | 59篇 |
2002年 | 46篇 |
2001年 | 64篇 |
2000年 | 52篇 |
1999年 | 35篇 |
1998年 | 11篇 |
1997年 | 4篇 |
1996年 | 10篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1992年 | 22篇 |
1991年 | 18篇 |
1990年 | 22篇 |
1989年 | 20篇 |
1988年 | 10篇 |
1987年 | 18篇 |
1986年 | 11篇 |
1985年 | 14篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 8篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1965年 | 4篇 |
排序方式: 共有1335条查询结果,搜索用时 0 毫秒
991.
992.
Fujii K Sato H Kakumoto C Kobayashi M Saito S Kariya T Watanabe Y Sakoda Y Kai C Kida H Suzuki M 《The Japanese journal of veterinary research》2006,54(2-3):109-117
Serological analysis was performed to detect morbillivirus infection in Kuril harbor seals in Hokkaido, Japan. Serum samples were collected from the seals at Nosappu (231 sera), Akkeshi (16), and Erimo (75) between 1998 and 2005. Antibodies to phocine distemper virus (PDV) were detected by ELISA in seals from Nosappu and Erimo. Antibodies to PDV were found in 56% (5/9) of the sampled seals from Nosappu in 1998, versus only 5% (3/66) for 2003, 1% (1/79) for 2004, and 1% (1/77) for 2005. These suggest epidemic caused by the virus in or before 1998. As antibody-positive seals included juvenile seals in 2003 and 2005, sporadic infections of the virus are thought to have occurred in recent years. In Erimo, antibodies to PDV were found in 50% (14/28) of sampled seals in 2004, versus only 13% (1/8) for 1999, 7% (1/15) for 2003, and 0% (0/24) for 2005. These suggest sporadic infection by the virus before 2003 and the epizootic between after autumn in 2003, when samples of 2003 were collected, and 2004. Since antibodies to canine distemper virus (CDV) were detected in one adult seal from Nosappu in each year from 2003 to 2005, sporadic infections of the virus were suggested. There were no difference in incidence of seals with antibodies to the viruses between males and females and between juveniles and adults. 相似文献
993.
994.
Oriented strand boards (OSB) were made using sugi wood strand with different lengths at different free fall distance conditions. Strand alignment and mechanical properties of sugi OSB were evaluated. Results obtained can be summarized as follows. The alignment angle distribution was greatly affected by both free fall distance and strand length. It was found that the standard deviation of the angles can be a measure for predicting the distribution when employing the von Mises distribution function with concentration parameter. The Monte Carlo simulation showed an agreement between the theoretical considerations and the experimental results on the strand alignment. The mechanical properties as affected by both strand length and layer structure were determined. Bending properties could be equal in both directions at 25% face layer ratio. Young's modulus obtained by the in-plane vibration method showed almost linear relation to the face layer ratio. No significant differences or only a slight difference was observed for the internal bond strength, plate-shear modulus, and nail resistance properties. Further studies are necessary. 相似文献
995.
Kayano S Yamada NF Suzuki T Ikami T Shioaki K Kikuzaki H Mitani T Nakatani N 《Journal of agricultural and food chemistry》2003,51(5):1480-1485
Prunes are known to show high antioxidant activity on the basis of the oxygen radical absorbance capacity (ORAC), and their major antioxidant components are caffeoylquinic acid isomers. The aim of this study is to prove the contribution of caffeoylquinic acid isomers to the ORAC of prunes, and to investigate the existence of other antioxidant components. Caffeoylquinic acid isomers in ethanol (EtOH) extracts of prunes were quantified by HPLC analysis, and the degree of contribution of these isomers to the ORAC was found to be 28.4%; hence, it was speculated that the remaining ORAC is dependent on other antioxidant compounds. EtOH extract was partitioned between hexane and H(2)O. The H(2)O layer was further separated into H(2)O and 2-100% methanol (MeOH) eluates by Diaion HP-20 column chromatography. Both the H(2)O and 50% MeOH eluates showed high values of total phenolics and ORAC, although the contribution of caffeoylquinic acid isomers to the ORAC was low. Therefore, it was predicted that unknown antioxidants exist in these fractions, and several compounds were identified by HPLC analysis. Furthermore, hydrolysis of EtOH extract residue led to higher levels of total phenolics and ORAC, and these results suggested the existence of conjugated antioxidant components in prunes. 相似文献
996.
An oral high dosage regimen of sulphadimethoxine (SDM) was examined in pigs. The dose (50 mg/kg) in the therapeutic range, showed nonlinear pharmacokinetics, and administered by drench once a day for 4 days. The unbound plasma concentration-time profile was compared with that of the dosage regimen based on nonlinear pharmacokinetics, where a pharmacokinetic model and parameters were used except for the first order absorption rate constant (ka) and bioavailability (F). F and ka were obtained from oral and intravenous administration of 20 and 10 mg/kg of SDM. The unbound plasma concentration was observed almost within the setting range by the dosage regimen through the experimental period. This result suggested that the dosage regimen, based on the nonlinear pharmacokinetic model, resulted in an appropriate effect in the clinical use. 相似文献
997.
The separation and identification of pigments, chlorophylls, and carotenoids of seven teas and fresh leaf of tea (Camellia sinensis) by high-performance liquid chromatography (HPLC) are described. HPLC was carried out using a Symmetry C(8) column with a photodiode array detector. Pigments were eluted with a binary gradient of aqueous pyridine solution at a flow rate of 1.0 mL/min at 25 degrees C. HPLC analyses achieved the separation of more than 100 pigment peaks, and 79 pigment species, 41 chlorophylls, and 38 carotenoids were detected. The presence of degraded chlorophylls was a common feature, and the number and the variety of pigments differed with tea species. Generally, the numbers of chlorophyll species tended to increase with processing steps, while carotenoid species were decreased, especially by heating. Particularly in green teas, a change of carotenoid structure, conversion of violaxanthin to auroxanthin, occurred. In hot water extracts of teas, both chlorophylls and carotenoids were also detected, but the concentration of chlorophylls was less than 2% as compared with acetone extracts. The pigment compositions were compared between tea species, and they are discussed in terms of the differences in their manufacturing processes. 相似文献
998.
999.
Ookawa K Mochizuki K Shida E Suzuki T Suzuki T Kitagawa T Matumoto T Hokari Y Yokogoshi H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(11):1207-1209
Ovary lipid of Skipjack tuna (OLS) (Katsuwonus pelamis) contains a high level of docosahexaenoic acid combined with phospholipids. In this study, we examined the effect of OLS in male Wistar rats given OLS mixed in feed (0.9%) for 42 days, using an animal model of anxiety, the elevated T-maze test. The avoidance latency at the 1st trial was significantly shorter in the OLS ingestion group than in the control group. Those at the 2nd and 3rd trials showed a similar tendency. There was almost no difference in escape latency at the 1st trial between the two groups but the escape latencies at the 2nd and 3rd trials tended to be longer in the OLS group. These results suggested that OLS inhibits anxious behavior in rats. 相似文献
1000.
Takayuki Kobayashi Daichi Asakawa Yukiko Yanagi Takeshi Suzuki Makiko Watanabe Hiroyuki Ohta Nobuhide Fujitake 《Soil Science and Plant Nutrition》2005,51(6):779-786
Chloroform-extractable green fraction (CEGF) was detected in the supernatant obtained by alkali precipitation from the HCI-dimethylsulfoxide (DMSO) extract of Pg-rich soil. In the alkaline solution, the color of CEGF was green and CEGF showed strong Pg-like absorption bands. Ultraviolet and visible (UV-VIS) spectral analysis and gel chromatography on Sephadex G-50 were performed to compare several properties between CEGF and Pg. CEGF, which was purified by gel chromatography on Bio-Beads SX-1, displayed strong absorption bands at 609, 562, 445 and 280 inn in the alkaline solution. These absorption bands were almost similar to those of Pg. Furthermore, the UV-VIS spectrum of CEGF in the organic solvents showed a similar characteristic pattern of 4,9-dihydroxyperylene-3,10-quinone (DHPQ), which was considered to be a chromophore of Pg. Based on the results of gel chromatography on Sephadex G-50, CEGF mainly consisted of two fractions, corresponding to the G2 and G3 fractions of Pg. These results indicated that the method for extracting CEGF from Pg-rich soil in the present study was easy and selective and that CEGF was one of the components of, or a closely related substance to Pg. A colorimetric method for the estimation of the CEGF content in soils was developed. The calibration curve of CEGF was linear over a wide range of contents from 2.75 to 220 mg L−1 . The CEGF content in twelve samples of various soils was examined. CEGF was detected in all the soil sampled (5 orders) including three samples (3 orders) where Pg was not detected, and the content ranged from 0.07 to 1.66 g kg−1 (dry soil). Therefore, the method for estimating the CEGF content in soils developed in the present study was found to be suitable for various soil orders and it was assumed that CEGF occurred in various soil orders. 相似文献