全文获取类型
收费全文 | 1293篇 |
免费 | 10篇 |
专业分类
林业 | 32篇 |
农学 | 1篇 |
171篇 | |
综合类 | 377篇 |
农作物 | 31篇 |
水产渔业 | 65篇 |
畜牧兽医 | 589篇 |
园艺 | 2篇 |
植物保护 | 35篇 |
出版年
2012年 | 96篇 |
2011年 | 113篇 |
2010年 | 20篇 |
2009年 | 6篇 |
2008年 | 98篇 |
2007年 | 86篇 |
2006年 | 92篇 |
2005年 | 85篇 |
2004年 | 79篇 |
2003年 | 76篇 |
2002年 | 64篇 |
2001年 | 50篇 |
2000年 | 60篇 |
1999年 | 27篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 11篇 |
1990年 | 10篇 |
1989年 | 42篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1984年 | 10篇 |
1983年 | 14篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1972年 | 4篇 |
1966年 | 6篇 |
1963年 | 11篇 |
1960年 | 4篇 |
1958年 | 10篇 |
1957年 | 6篇 |
1956年 | 6篇 |
1954年 | 5篇 |
1948年 | 5篇 |
1947年 | 6篇 |
1946年 | 4篇 |
1945年 | 4篇 |
1941年 | 4篇 |
1934年 | 3篇 |
1924年 | 3篇 |
排序方式: 共有1303条查询结果,搜索用时 15 毫秒
161.
Dicko MH Gruppen H Traore AS van Berkel WJ Voragen AG 《Journal of agricultural and food chemistry》2005,53(7):2581-2588
The screening of 50 sorghum varieties showed that, on average, germination did not affect the content in total phenolic compounds but decreased the content of proanthocyanidins, 3-deoxyanthocyanidins, and flavan-4-ols. Independent of germination, there are intervarietal differences in antioxidant activities among sorghum varieties. Phenolic compounds and antioxidant activities were more positively correlated in ungerminated varieties than in germinated ones. Sorghum grains with pigmented testa layer, chestnut color glumes, and red plants had higher contents, larger diversity of phenolic compounds, and higher antioxidant activities than other sorghums. Some red sorghum varieties had higher antioxidant activities (30-80 mumol of Trolox equiv/g) than several sources of natural antioxidants from plant foods. Among varieties used for "to", "dolo", couscous, and porridge preparation, the "dolo"(local beer) varieties had the highest average content and diversity in phenolic compounds as well as the highest antioxidant activities. The biochemical markers determined are useful indicators for the selection of sorghum varieties for food and agronomic properties. 相似文献
162.
Dicko MH Hilhorst R Gruppen H Traore AS Laane C van Berkel WJ Voragen AG 《Journal of agricultural and food chemistry》2002,50(13):3780-3788
Analysis of fifty sorghum [Sorghum bicolor (L.) Moench] varieties used in Burkina Faso showed that they have different contents of phenolic compounds, peroxidase (POX), and polyphenol oxidase (PPO). Most of the varieties (82%) had a tannin content less than 0.25% (w/w). POX specific activity was higher than the monophenolase and o-diphenolase specific activities of PPO. For POX, there was a diversity of isoforms among varieties. No clear correlation could be made between the quantitative composition of the grain in phenolics, PPO, and POX, and resistance of plant to pathogens. In general, varieties good for a thick porridge preparation ("t?") had low phenolic compounds content and a medium POX activity. From the red varieties, those used for local beer ("dolo") had a high content in phenolic compounds and PPO, and a low POX activity. The variety considered good for couscous had a low POX content. The characteristics might be useful as selection markers for breeding for specific applications. 相似文献
163.
Induction of apoptosis by garcinol and curcumin through cytochrome c release and activation of caspases in human leukemia HL-60 cells 总被引:5,自引:0,他引:5
Pan MH Chang WL Lin-Shiau SY Ho CT Lin JK 《Journal of agricultural and food chemistry》2001,49(3):1464-1474
Garcinol, a polyisoprenylated benzophenone, was purified from Garcinia indica fruit rind. The effects of garcinol and curcumin on cell viability in human leukemia HL-60 cells were investigated. Garcinol and curcumin displayed strong growth inhibitory effects against human leukemia HL-60 cells, with estimated IC(50) values of 9.42 and 19.5 microM, respectively. Garcinol was able to induce apoptosis in a concentration- and time-dependent manner; however, curcumin was less effective. Treatment with garcinol caused induction of caspase-3/CPP32 activity in a dose- and time-dependent manner, but not caspase-1 activity, and induced the degradation of poly(ADP-ribose) polymerase (PARP). Pretreatment with caspase-3 inhibitor inhibited garcinol-induced DNA fragmentation. Treatment with garcinol (20 microM) caused a rapid loss of mitochondrial transmembrane potential, release of mitochondrial cytochrome c into cytosol, and subsequent induction of procaspase-9 processing. The cleavage of D4-GDI, an abundant hematopoietic cell GDP dissociation inhibitor for the Ras-related Rho family GTPases, occurred simultaneously with the activation of caspase-3 but preceded DNA fragmentation and the morphological changes associated with apoptotic cell death. Of these, Bcl-2, Bad, and Bax were studied. The level of expression of Bcl-2 slightly decreased, while the levels of Bad and Bax were dramatically increased in cells treated with garcinol. These results indicate that garcinol allows caspase-activated deoxyribonuclease to enter the nucleus and degrade chromosomal DNA and induces DFF-45 (DNA fragmentation factor) degradation. It is suggested that garcinol-induced apoptosis is triggered by the release of cytochrome c into the cytosol, procaspase-9 processing, activation of caspase-3 and caspase-2, degradation of PARP, and DNA fragmentation caused by the caspase-activated deoxyribonuclease through the digestion of DFF-45. The induction of apoptosis by garcinol may provide a pivotal mechanism for its cancer chemopreventive action. 相似文献
164.
Potent fibrinolytic enzyme from a mutant of Bacillus subtilis IMR-NK1 总被引:10,自引:0,他引:10
A mutant of Bacillus subtilis IMR-NK1, which is used for the production of domestic "natto" in Taiwan, produced high fibrinolytic enzyme activity by solid-state fermentation using wheat bran as medium. In addition, a strong fibrinolytic enzyme was purified from the cultivation media. The purified enzyme was almost homogeneous, as examined by SDS-PAGE and capillary electrophoresis. The enzyme had an optimal pH of 7.8, an optimal temperature of 55 degrees C, and a K(m) of 0.15% for fibrin hydrolysis. The molecular mass estimated by gel filtration was 31.5 kDa, and the isoelectric point estimated by isoelectric focusing electrophoresis was 8.3. The enzyme also showed activity for hydrolysis of fibrinogen, casein, and several synthetic substrates. Among the synthetic substrates, the most sensitive substrate was N-succinyl-Ala-Ala-Pro-Phe-pNA. PMSF and NBS almost completely inhibited the activity of the enzyme. These results indicate that the enzyme is a subtilisin-like serine protease, similar to nattokinase from Bacillus natto. 相似文献
165.
Effects of garlic powders with varying alliin contents on hepatic drug metabolizing enzymes in rats 总被引:3,自引:0,他引:3
Le Bon AM Vernevaut MF Guenot L Kahane R Auger J Arnault I Haffner T Siess MH 《Journal of agricultural and food chemistry》2003,51(26):7617-7623
The anticarcinogenic effect of garlic has been demonstrated in both epidemiologic and experimental studies. In this study, possible mechanisms involved in the anticarcinogenic effect of garlic consumption were assessed by determining its capacity to alter drug metabolizing enzymes, in relation with its alliin content. Rats were fed a diet for 2 weeks containing 5% garlic powders produced from bulbs grown on soils with different levels of sulfate fertilization and therefore containing differing amounts of alliin. Activities of several hepatic enzymes, which are important in carcinogen metabolism such cytochromes P450 (CYP) and phase II enzymes, were determined. Garlic consumption slightly increased ethoxyresorufin O-deethylase and CYP 1A2 levels. In contrast, garlic consumption decreased CYP 2E1 activity and the level of the corresponding isoform. UDP glucuronosyl transferase and glutathion S-transferase activities were increased by garlic powders. The alliin content of the garlic powders was positively correlated with UGT activity although not with other activities. Effects produced by garlic consumption were qualitatively similar to that of diallyl disulfide, a sulfur compound that has been extensively studied. These data could partially explain the chemoprotective effect of garlic. 相似文献
166.
167.
168.
169.
ZIMMERMANN MH 《Science (New York, N.Y.)》1955,122(3173):766
170.
Mutual adhesiveness and aggregation of dissociated embryonic retina cells in suspension cultures are suppressed rapidly and reversibly by puromycin, an inhibitor of RNA-dependent protein synthesis; and at a slower rate, irreversibly, by actinomycin D, an inhibitor of RNA formation. The results imply that biosynthetic processes are involved in the mechanism of reattachment of these cells. 相似文献