全文获取类型
收费全文 | 880篇 |
免费 | 35篇 |
专业分类
林业 | 120篇 |
农学 | 45篇 |
129篇 | |
综合类 | 25篇 |
农作物 | 35篇 |
水产渔业 | 88篇 |
畜牧兽医 | 391篇 |
园艺 | 5篇 |
植物保护 | 77篇 |
出版年
2023年 | 3篇 |
2022年 | 13篇 |
2021年 | 25篇 |
2020年 | 19篇 |
2019年 | 11篇 |
2018年 | 15篇 |
2017年 | 22篇 |
2016年 | 34篇 |
2015年 | 39篇 |
2014年 | 44篇 |
2013年 | 77篇 |
2012年 | 55篇 |
2011年 | 64篇 |
2010年 | 32篇 |
2009年 | 42篇 |
2008年 | 60篇 |
2007年 | 51篇 |
2006年 | 70篇 |
2005年 | 55篇 |
2004年 | 56篇 |
2003年 | 56篇 |
2002年 | 34篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1996年 | 1篇 |
1991年 | 2篇 |
1988年 | 2篇 |
1983年 | 1篇 |
排序方式: 共有915条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
Satoshi Haga Hiroshi Ishizaki Miwa Nakano Seiji Nakao Kiyoshi Hirano Yoshito Yamamoto Miya Kitagawa Hiroyuki Sasaki Yoshihiro Kariya 《Animal Science Journal》2014,85(2):135-142
Blood total antioxidant capacity (TAC) has become a key bio‐marker for animal health. Forest‐grazing cattle are known to forage various native plants that have high TAC. This study evaluated differences of plasma TAC between forest‐grazing (FG) and pasture‐grazing cattle (PG). Experiment 1 monitored the plasma TAC levels of 32 Japanese Black cattle. The level in PG did not change throughout the grazing period. However, that in FG, which increased from summer, was significantly higher than that in PG through fall (P < 0.05). In experiment 2, we used nine Japanese Black heifers and investigated their blood antioxidant parameters and the TAC in plants that the cattle consumed in late June and September. The plasma TAC levels in FG were significantly higher than those in PG in both periods (P < 0.05). Plasma levels of lipid peroxidation in FG tended to be lower than that in PG (P = 0.098). Furthermore, the TAC levels in various species of shrubs and trees consumed by FG were higher than those in pasture grasses. Results of this study show that plasma TAC of grazing Japanese Black cattle in forestland increase from summer through fall. 相似文献
56.
Takashi?KamiyamaEmail author Hiroyuki?Yamauchi Takuro?Iwai Shoichi?Hanawa Yukihiko?Matsuyama Satoshi?Arima Yuichi?Kotani 《Fisheries Science》2005,71(6):1295-1303
ABSTRACT: Sea water environmental conditions over annual cycles were investigated and compared between two oyster farming areas, western Hiroshima Bay and Oginohama Bay (a branch of Ishinomaki Bay) in Miyagi Prefecture, to appropriately manage oyster culture or more efficiently utilize farming areas. The environmental parameters of temperature, salinity, nutrient concentrations (NO2 –N, NO3 –N, NH4 –N, PO4 –P, and SiO2 –Si) and size-fractionated chlorophyll- a (<0.2, 2–20, >20µm), and abundances of microzooplankton were measured in each bay at the surface, and 2 and 5 m depth layers. Differences in the annual mean values and results with monthly paired Student's t -tests showed that salinity was lower, and temperature, nutrient (especially PO4 –P) and chlorophyll- a concentrations, and abundance of microzooplankton, were higher in Hiroshima Bay than in Oginohama Bay. Differences in environmental conditions between inshore and offshore areas of each bay suggest that inflows of river water in western Hiroshima Bay and sea water from offshore had the most significant effects on the environmental conditions. It is concluded that such oceanographic and biological differences strongly affect the oyster farming system, especially regarding the optimum usage of offshore areas in Summer under clean, cold and stable seawater conditions, rather than food quantity in Hiroshima Bay, and under more abundant food conditions in Oginohama Bay. 相似文献
57.
The size of harvests temporarily decreases following stock-recovery programs for overexploited resources. The process of stock recovery is quite uncertain, because of unknown life-history parameters, changes in environmental conditions, and human impact. To project future stock recovery, we considered a size-structured matrix model of a stock-recovery program, in which the minimum body size in the first harvest is increased. We applied some common concepts, including yield per recruitment, spawning per recruitment, and reproductive value, to a size-structured matrix model that incorporated economic discounting. The size-structured model predicted the following characteristics in stock-recovery processes: several years must pass for the harvest to increase, and the time-lag between the inception of the management program and the increase in the catch is caused by intergenerational momentum in demography. We also investigated the effects on the recovery process of temporal environmental fluctuations. We applied our model to a stock-recovery program of the corbiculid Seta clam (Corbicula sandai) in Lake Biwa, Japan. 相似文献
58.
Five new nucleoside antibiotics, named streptcytosines A–E (1–5), and six known compounds, de-amosaminyl-cytosamine (6), plicacetin (7), bamicetin (8), amicetin (9), collismycin B (10), and SF2738 C (11), were isolated from a culture broth of Streptomyces sp. TPU1236A collected in Okinawa, Japan. The structures of new compounds were elucidated on the basis of their spectroscopic data (HRFABMS, IR, UV, and 2D NMR experiments including 1H-1H COSY, HMQC, HMBC, and NOESY spectra). Streptcytosine A (1) belonged to the amicetin group antibiotics, and streptcytosines B–E (2–5) were derivatives of de-amosaminyl-cytosamine (6), 2,3,6-trideoxyglucopyranosyl cytosine. Compound 1 inhibited the growth of Mycobacterium smegmatis (MIC = 32 µg/mL), while compounds 2–5 were not active at 50 µg/disc. Bamicetin (8) and amicetin (9) showed the MICs of 16 and 8 µg/mL, respectively. 相似文献
59.
Okumura S Saitoh H Ishikawa T Wasano N Yamashita S Kusumoto K Akao T Mizuki E Ohba M Inouye K 《Journal of agricultural and food chemistry》2005,53(16):6313-6318
Parasporal inclusion proteins produced by Bacillus thuringiensis strain A1470 exhibit strong cytotoxicity against human leukemic T cells when activated by protease treatment. One of the cytotoxic proteins was separated by anion exchange chromatography and gel filtration chromatography and designated Cry45Aa. Its gene was then expressed in recombinant Escherichia coli, in which the Cry45Aa precursor was accumulated in an inclusion body. It was solubilized in sodium carbonate buffer and processed with proteinase K, and cytotoxic activities of the protein against various mammalian cell lines were evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide assay. The protein exhibited high cytotoxic activity against CACO-2, Sawano, MOLT-4, TCS, and HL60 cells and moderate activity against U-937 DE-4, PC12, and HepG2 cells. On the other hand, the EC50 values against Jurkat, K562, HeLa, A549, Vero, COS-7, NIH3T3, CHO, and four normal tissue cells (human primary hepatocyte cells, UtSMC, MRC-5, and normal T cells) were >2 microg/mL. 相似文献
60.
Quahir Sohail Tomoe Inoue Hiroyuki Tanaka Amin Elsadig Eltayeb Yoshihiro Matsuoka Hisashi Tsujimoto 《Breeding Science》2011,61(4):347-357
Few genes are available to develop drought-tolerant bread wheat (Triticum aestivum L.) cultivars. One way to enhance bread wheat’s genetic diversity would be to take advantage of the diversity of wild species by creating synthetic hexaploid wheat (SW) with the genomic constitution of bread wheat. In this study, we compared the expression of traits encoded at different ploidy levels and evaluated the applicability of Aegilops tauschii drought-related traits using 33 Ae. tauschii accessions along with their corresponding SW lines under well-watered and drought conditions. We found wide variation in Ae. tauschii, and even wider variation in the SW lines. Some SW lines were more drought-tolerant than the standard cultivar Cham 6. Aegilops tauschii from some regions gave better performing SW lines. The traits of Ae. tauschii were not significantly correlated with their corresponding SW lines, indicating that the traits expressed in wild diploid relatives of wheat may not predict the traits that will be expressed in SW lines derived from them. We suggest that, regardless of the adaptability and performance of the Ae. tauschii under drought, production of SW could probably result in genotypes with enhanced trait expression due to gene interactions, and that the traits of the synthetic should be evaluated in hexaploid level. 相似文献