全文获取类型
收费全文 | 260篇 |
免费 | 0篇 |
专业分类
17篇 | |
综合类 | 62篇 |
农作物 | 8篇 |
水产渔业 | 1篇 |
畜牧兽医 | 160篇 |
植物保护 | 12篇 |
出版年
2012年 | 9篇 |
2011年 | 23篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 12篇 |
2007年 | 20篇 |
2006年 | 17篇 |
2005年 | 28篇 |
2004年 | 17篇 |
2003年 | 15篇 |
2002年 | 14篇 |
2001年 | 15篇 |
2000年 | 14篇 |
1999年 | 8篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1963年 | 2篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1953年 | 2篇 |
1948年 | 1篇 |
1946年 | 2篇 |
1940年 | 1篇 |
1926年 | 1篇 |
1917年 | 1篇 |
排序方式: 共有260条查询结果,搜索用时 156 毫秒
61.
Ponder J Yoo BH Abraham AD Li Q Ashley AK Amerin CL Zhou Q Reid BG Reigan P Hromas R Nickoloff JA LaBarbera DV 《Marine drugs》2011,9(11):2397-2408
Type IIα DNA topoisomerase (TopoIIα) is among the most important clinical drug targets for the treatment of cancer. Recently, the DNA repair protein Metnase was shown to enhance TopoIIα activity and increase resistance to TopoIIα poisons. Using in vitro DNA decatenation assays we show that neoamphimedine potently inhibits TopoIIα-dependent DNA decatenation in the presence of Metnase. Cell proliferation assays demonstrate that neoamphimedine can inhibit Metnase-enhanced cell growth with an IC(50) of 0.5 μM. Additionally, we find that the apparent K(m) of TopoIIα for ATP increases linearly with higher concentrations of neoamphimedine, indicating ATP-competitive inhibition, which is substantiated by molecular modeling. These findings support the continued development of neoamphimedine as an anticancer agent, particularly in solid tumors that over-express Metnase. 相似文献
62.
This study aims to justify effects of niacin and folic acid in feed rations on growth and survival rate of the fish under in vitro conditions. A Completely Randomized Design (CRD) with four replications for Experiment I and three replications for Experiment II was used. Niacin (0, 5, 10, 20 and 40 mg kg(-1)) and folic acid (0, 2, 4, 6 and 8 mg kg(-1)) were used for Experiments I, and II, respectively. The cement tanks were used for Experiment I and fibre tanks for Experiment II. A static water system was used. Water temperature was maintained at a range from 26 to 30 degrees C with pH values from 7.4 to 7.9. The results showed that niacin at a rate of 10 mg kg(-1) feed ration gave significant differences on weight gained %, survival %, protein efficiency ratio, specific growth rate % and feed conversion ratio with mean values of 99.92, 100, 1.18, 5.77 and 1.35, respectively. Folic acid at a rate of 2 mg kg(-1) gave significant differences on weight gained %, survival %, protein efficiency ratio, specific growth rate % and feed conversion ratio with mean values of 108.88, 100, 1.22, 6.13 and 1.43, respectively. Niacin at a rate of 10 and 2 mg kg(-1) of folic acid were the best rates for in vitro culture of Green catfish. 相似文献
63.
64.
Rème CA Dramard V Kern L Hofmans J Halsberghe C Mombiela DV 《Veterinary therapeutics : research in applied veterinary medicine》2008,9(2):69-82
Oral S-adenosylmethionine (SAMe) tosylate supplementation (Novifit tablets, Virbac) was evaluated as a dietary aid for the management of age-related mental impairment in dogs. Thirty-six dogs older than 8 years that had displayed signs of cognitive dysfunction for at least 1 month were selected for the study. The dogs were administered 18 mg/kg SAMe tosylate (n=17) or identical placebo tablets (n=19) for 2 months. Concurrent behavioral treatment was forbidden. A 14-item standardized questionnaire evaluated behavior and locomotion difficulties. Compared with the placebo group, SAMe-treated dogs showed greater improvement in activity (41.7% versus 2.6% after 4 weeks, P<.0003; 57.1% versus 9.0% after 8 weeks, P<.003) and awareness (33.3% versus 17.9% after 4 weeks, P<.05; 59.5% versus 21.4% after 8 weeks, P<.01). The aggregate mental impairment score was reduced by more than 50% in 41.2% and 15.8% of dogs treated with SAMe and placebo, respectively, at week 8. SAMe tosylate tablets proved safe and effective in improving signs of age-related mental decline in dogs. 相似文献
65.
66.
de Souza PP Siebald HG Augusti DV Neto WB Amorim VM Catharino RR Eberlin MN Augusti R 《Journal of agricultural and food chemistry》2007,55(6):2094-2102
We have investigated the capability of direct infusion electrospray ionization mass spectrometry in the negative ion mode, ESI(-)-MS, to differentiate representative samples of artisan cacha?a, a Brazilian sugar cane distillate of large production, aged in four different types of wood casks: amburana (Amburana cearensis), jequitibA (Cariniana estrellensis), balm (Myroxylon peruiferum), and oak (Quercus rubra). The ESI(-)-MS were found to be very characteristic, showing sets of diagnostic ions for each of the four types of samples: amburana (m/z 271, 313, 377), jequitibA (m/z 143, 171, 255), balm (m/z 137, 269, 283, 297), and oak (m/z 197, 301, 307). Furthermore, principal component (PCA) and hierarchical cluster analysis (HCA), applied to the ESI(-)-MS data, divided these samples into four definite categories. The influence of the aging time on the ESI(-)-MS fingerprints of the cacha?a samples stored in oak casks was also established. An inversion in the relative intensity of the diagnostic ions of m/z 307 and 301 is detected in the ESI(-)-MS as the aging time increased from 1 to 2 years. The chemical structures of the major cacha?a components were proposed on the basis of the following: (a) the comparison of the ESI(-)-MS/MS of the diagnostic anions with those of the authentic anions or (b) the interpretation of the fragmentation patterns of the previously unknown diagnostic anions. Hence, direct infusion ESI(-)-MS allows not only a rapid, simple, and accurate way to distinguish among cacha?a samples stored in different wood casks but also monitoring changes in their chemical composition according to the aging time. 相似文献
67.
Yu J Dandekar DV Toledo RT Singh RK Patil BS 《Journal of agricultural and food chemistry》2006,54(16):6041-6045
Limonoid glucosides (primarily limonin 17-beta-D-glucopyranoside, LG) were extracted from grapefruit molasses by supercritical fluid extraction using a supercritical carbon dioxide-ethanol (SC CO(2)-ethanol) system. Extraction conditions to maximize the yield of LG were determined by varying pressure, temperature, ethanol concentration, and extraction time. The highest yield of LG at 0.61 mg/g molasses was obtained at a pressure 48.3 MPa, a temperature of 50 degrees C, 10% ethanol (X(Eth) = 0.1), and 40 min of extraction time at a flow rate of 5.0 L/min. The results demonstrated that SC CO(2) extraction of limonoid glucosides from grapefruit molasses has practical significance for commercial production. 相似文献
68.
Manuja A Malhotra DV Sikka VK Sangwan AK Sharma R Kumar B Mehta BD Gulati BR Nichani AK 《Veterinary parasitology》2006,137(3-4):242-252
Phenotypic and genetic polymorphism was studied amongst four Theileria annulata isolates collected from three different parts of India. Amongst various markers studied for the comparison of growth characteristics of schizont cell lines established from these isolates, viability, non-viability counts and nitric oxide (NO) production showed significant variation. A negative correlation was observed between NO production and mRNA expression for TNF-alpha, a potent proinflammatory cytokine related to the pathogenesis of the disease. Phenotypic polymorphism was also revealed by T. annulata schizont-specific monoclonal antibodies (Mabs), viz. 1C7, 1E11, 2G2 and EU-106, which recognized variable number of cells in indirect fluorescent antibody and indirect immunoperoxidase tests, when tested against the four T. annulata isolates collected from India. Genetic polymorphism was recognized amongst the four isolates by restriction digestion analysis of Tams-1 gene PCR products. These observations revealed that the four isolates of T. annulata are different from each other and might be expressing different antigenic determinants on their cell surface. 相似文献
69.
任何人工授精公猪站都应该定期对稀释精液单剂进行品质监控,可以通过内部品控程序,也可委托第三方组织进行,以期保证精液的授精能力,让情期中按正确的时机授精的后备母猪和经产母猪都能妊娠。品控程序应该对每剂精液的精子细胞数量、精子活力、精子形态进行检测评估,并对可能存在的微生物污染情况进行排查。 相似文献
70.
AJ Burton DV Nydam KJ Mitchell DD Bowman 《Journal of the American Veterinary Medical Association》2012,241(4):496-498
Objective-To determine the apparent prevalence of shedding of Cryptosporidium spp in healthy alpaca crias and their dams on 14 farms in New York and 1 farm in Pennsylvania. Design-Cross-sectional study. Animals-110 alpaca crias and their 110 dams. Procedures-Fecal samples were obtained from 220 alpacas at 14 alpaca farms in New York and 1 farm in Pennsylvania. For each animal, age, sex, and health condition were recorded. A fecal score (1 = normally formed; 2 = soft or loose; 3 = diarrhetic) was recorded for each cria. Cryptosporidium oocysts were identified in fecal samples by a direct immunofluorescence assay. Results-Apparent prevalence of fecal shedding of Cryptosporidium oocysts was 8% (95% confidence interval, 4% to 15%) in dams and was 7% (95% confidence interval, 3% to 13%) in crias. There was no significant difference in age between dams with positive fecal test results for Cryptosporidium oocysts (median age, 4 years; range, 3 to 8 years) and dams with negative results (median age, 4 years; range, 2.5 to 19 years). No significant difference was found in age between crias with positive fecal test results (median age, 20 days; range, 7 to 53 days) and those with negative results (median, 36 days; range, 2 to 111 days). No significant difference in fecal scores was found between crias with positive versus negative fecal test results. Conclusions and Clinical Relevance-A higher than previously reported apparent prevalence of fecal shedding of Cryptosporidium oocysts in healthy alpacas was found. A zoonotic risk should be considered, especially for Cryptosporidium parvum. 相似文献