全文获取类型
收费全文 | 1568篇 |
免费 | 118篇 |
国内免费 | 3篇 |
专业分类
林业 | 94篇 |
农学 | 34篇 |
基础科学 | 3篇 |
320篇 | |
综合类 | 249篇 |
农作物 | 59篇 |
水产渔业 | 160篇 |
畜牧兽医 | 606篇 |
园艺 | 70篇 |
植物保护 | 94篇 |
出版年
2023年 | 14篇 |
2022年 | 15篇 |
2021年 | 37篇 |
2020年 | 40篇 |
2019年 | 59篇 |
2018年 | 43篇 |
2017年 | 48篇 |
2016年 | 57篇 |
2015年 | 38篇 |
2014年 | 38篇 |
2013年 | 73篇 |
2012年 | 89篇 |
2011年 | 101篇 |
2010年 | 53篇 |
2009年 | 65篇 |
2008年 | 101篇 |
2007年 | 90篇 |
2006年 | 106篇 |
2005年 | 79篇 |
2004年 | 89篇 |
2003年 | 85篇 |
2002年 | 69篇 |
2001年 | 28篇 |
2000年 | 28篇 |
1999年 | 23篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 18篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 16篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1979年 | 6篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1968年 | 6篇 |
1967年 | 3篇 |
1964年 | 4篇 |
1963年 | 3篇 |
1962年 | 3篇 |
排序方式: 共有1689条查询结果,搜索用时 265 毫秒
1.
Kevin R. Stuart Arnold G. Eversole David E. Brune 《Journal of the World Aquaculture Society》2001,32(1):105-111
Abstract.— The freshwater mussel Elliptio complanata was provided water containing green algae and cyanobacteria delivered from the Partitioned Aquaculture System (PAS) at eight flow rates to determine algal filtration rates as mg of particulate organic carbon (POC)/kg wet tissue weight per h. The dominant taxon in cyanobacterial waters was Microcystis while the dominant taxa in green algal waters were Scenedesmus and Ankistrodesmus . The cell counts of Scenedesmus and Ankistrodesmus were the only algal taxa that were significantly different between the incoming water and water filtered by mussels. Filtration rates of POC obtained from green algal water were significantly greater than from cyanobacteria-dominated waters at all flow rates. A significant increase in mean filtration rate was observed as flow rates increased. The filtration rate of green algae increased as POC concentration increased, peaking at 28 mg C/L. A maximum filtration rate was not observed with cyanobacterial waters. 相似文献
2.
PULMONARY MINERALIZATION IN FOUR DOGS WITH CUSHING'S SYNDROME 总被引:1,自引:0,他引:1
Clifford R. Berry DVM Norman Ackerman DVM Kevin Monce DVM 《Veterinary radiology & ultrasound》1994,35(1):10-16
The clinical and imaging features of four dogs with Cushing's syndrome and pulmonary mineralization are reviewed. Three dogs presented with a primary complaint of respiratory distress/dyspnea. Three dogs had pituitary dependent Cushing's syndrome, while the remaining one dog had iatrogenic Cushing's syndrome. Each dog had clinical features typical for Cushing's syndrome. Two of the dogs were euthanized due to progressive hypoxemia. In each dog, the serum calcium, phosphorous, blood urea nitrogen and creatinine were normal.
A generalized increase in unstructured interstitial pulmonary opacity with diffuse mineralization was noted on thoracic radiographs of all dogs. In one dog, an ill-defined nodular interstitial pattern of mineralization was present. Delayed bone phase scintigraphy using99m Technetium methylene diphosphonate documented generalized pulmonary uptake in two dogs. 99m Technetium labeled microaggregated albumin lung perfusion scans were normal in these two dogs. 99m Tc-MDP scintigraphy can provide useful information in diagnosing pulmonary mineralization in Cushingoid dogs. 相似文献
A generalized increase in unstructured interstitial pulmonary opacity with diffuse mineralization was noted on thoracic radiographs of all dogs. In one dog, an ill-defined nodular interstitial pattern of mineralization was present. Delayed bone phase scintigraphy using
3.
4.
5.
A single, artificially-induced fly-strike with Lucilia sericata larvae was associated with a rapid (decline in food intake in sheep, with a consequent reduction in liveweight. Loss of weight ranged from 0.5 to 5.5 kg over four to six days and recovery to pre-infestation liveweight took three to 36 days. Pair-fed, uninfested partners of these sheep also showed a reduction in liveweight, whereas uninfested sheep in some experiments fed ad libitum showed either little change or a gain in liveweight over the same period. In general, maggot infested sheep took less time to regain weight than did their pair-fed partners although the weight lost as a proportion of initial weight was similar in both groups. Loss of appetite alone would appear to account for these events. 相似文献
6.
M D Bishop M E Davis W R Harvey G R Wilson B D VanStavern 《Journal of animal science》1991,69(11):4360-4367
A single generation divergent selection study, replicated four times (1983, 1984, 1985, and 1986), was conducted to assess genetic differences between progeny of high and low feed conversion sires in Angus beef cattle and to determine correlated response for weight gain (ADG140), feed intake (AVFD140), and BW (OFFTSTWT) in a time- (140-d) and fat-constant (8.9 mm) period. Realized heritability estimates for unadjusted (feed/gain; FEFF140; .26) and adjusted feed conversion (adjusted as recommended by the BIF, 1986; ADJFDEFF; .46) were obtained. The difference in heritability estimates reflects variation accounted for by adjustment for BW differences, and thus maintenance requirements, of individual progeny. Phenotypic and "pseudo" realized genetic correlations of FEFF140 with ADG140, AVFD 140, and OFFTSTWT were -.33 and -.66, .49 and -.26, and .15 and -.41, respectively. Phenotypic and "pseudo" realized genetic correlations of ADJFDEFF with ADG140, AVFD140, OFFTSTWT, and FEFF140 were -.54 and -.59, .30 and -.23, .27 and -.36, and .97 and .49, respectively. Subcutaneous fat (as estimated by ultrasonic measurement; BF140) had phenotypic and "pseudo" realized genetic correlations with FEFF140 of -.33 and .66, respectively, and with ADJFDEFF of -.44 and -.58, respectively. 相似文献
7.
8.
9.
10.
The comparative efficacy of 13 of the sheep dips currently registered in New Zealand was investigated using sheep infested with the louse Bovicola ovis and carrying wool which was about 10 cm long at the shoulder. With the exception of one synthetic pyrethroid pour-on formulation, all products were able to effect a significant reduction in louse populations, relative to untreated controls, for 37 days after treatment. Only four products proved capable of eradicating lice and preventing their re-establishment up to 37 days after treatment. Variations in manufacturers' recommendations relating to the length of wool at dipping, and mode of application of dips are discussed in relation to the results. 相似文献