全文获取类型
收费全文 | 440篇 |
免费 | 39篇 |
专业分类
林业 | 26篇 |
农学 | 7篇 |
基础科学 | 3篇 |
70篇 | |
综合类 | 36篇 |
农作物 | 18篇 |
水产渔业 | 38篇 |
畜牧兽医 | 249篇 |
园艺 | 8篇 |
植物保护 | 24篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 12篇 |
2021年 | 17篇 |
2020年 | 16篇 |
2019年 | 22篇 |
2018年 | 25篇 |
2017年 | 16篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 20篇 |
2013年 | 26篇 |
2012年 | 32篇 |
2011年 | 32篇 |
2010年 | 20篇 |
2009年 | 14篇 |
2008年 | 27篇 |
2007年 | 31篇 |
2006年 | 20篇 |
2005年 | 26篇 |
2004年 | 24篇 |
2003年 | 22篇 |
2002年 | 10篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有479条查询结果,搜索用时 15 毫秒
111.
Prospective evaluation of outcome of dogs with intrahepatic portosystemic shunts treated via percutaneous transvenous coil embolization
下载免费PDF全文
![点击此处可从《Veterinary surgery : VS》网站下载免费的PDF全文](/ch/ext_images/free.gif)
112.
113.
Jane E. Quandt DVM DACVAA DACVECC Michele Barletta DVM MS PhD DACVAA Karen K. Cornell DVM PhD DACVS Steeve Giguère DVM PhD DACVIM Erik H. Hofmeister DVM MA DACVAA DECVAA 《Journal of Veterinary Emergency and Critical Care》2018,28(1):45-53
Objective
To assess agreement between a point‐of‐care glucometer (POCG) and a laboratory chemistry analyzer for blood glucose measurements in goats.Design
Prospective study.Setting
University teaching hospital.Animals
Eighteen healthy adult goats.Investigations
Whole blood samples were obtained via jugular venipuncture prior to premedication with xylazine and butorphanol (T0), following premedication (T20), and after 1 hour of inhalant anesthesia (T60). Each sample was tested with a POCG and a laboratory analyzer (HITA). Agreement was assessed using concordance correlation coefficients and calculation of bias and 95% limits of agreement.Measurements and Main Results
Mean blood glucose concentration at T0 was 3.9 ± 0.6 mmol/L (70 ± 10 mg/dL; POCG) and 2.9 ± 0.4 mmol/dL (53 ± 8 mg/dL; HITA). Glucose concentrations at T20 were 6.7 ± 2.4 mmol/L (121 ± 43 mg/dL) and 5.4 ± 2.1 mmol/L (97 ± 37 mg/dL) and at T60 were 5.7 ± 1.7 mmol/L (102 ± 31 mg/dL) and 4.7 ± 1.3 mmol/L (85 ± 24 mg/dL) when measured with the POCG and HITA, respectively. The POCG overestimated blood glucose compared to the HITA. The bias ± SD was 1.08 ± 0.53 mmol/L (19.4 ± 9.5 mg/dL) (95% LOA 0.04 to 2.11 mmol/L [0.7 to 38.0 mg/dL]) and the concordance correlation coefficient was 0.82. After correcting the results of the POCG using a mixed‐effects linear model, the bias was 0.0 ± 0.38 mmol/L (0.0 ± 6.8 mg/dL) (95% LOA ± 0.74 mmol/L [± 13.4 mg/dL]) and the concordance correlation coefficient was 0.98.Conclusions
The POCG overestimated blood glucose concentrations in goats, compared to the HITA, but when the POCG concentrations were corrected, the agreement was excellent. 相似文献114.
Michele Scotton 《Strength and Conditioning Journal》2018,71(6):762-769
Wild harvesting is an efficient option for supplying seed to be used for restoring seminatural grasslands. Several methods are currently used to implement wild harvesting, but few controlled experiments have investigated its efficiency regarding seed amount and number of species collected. A harvesting trial was conducted in a species-rich, low-productivity grassland of the calcareous Italian Alps (1 030 m above sea level [a.s.l.). Three mechanical methods were tested in three replications using a completely randomized block design: green hay (GH), dry hay (DH), and seed stripping (SS) harvesting. The number of fertile shoots, mature seeds, and species collected was recorded and compared with the standing seed yield (SSY). GH, DH, and SS harvested approximately 84%, 70%, and 29% of SSY, respectively. Forbs were harvested more efficiently than grasses in all methods but in most cases at very low seed amounts per m2 due to their low seed density for SSY. No significant difference among methods was found for the number of species collected as mature seeds, but SS, implemented on larger plots, tended to collect more forb species. Comparing the results with those of other experiments demonstrated that the relatively cool temperature of the seed maturation period at the mountain site favored stronger seed retention and therefore increased the GH and DH efficiency but decreased the SS efficiency. In cool mountain areas, wild harvesting from forb-rich grasslands should be more successful by SS implemented on wide areas and several times over the vegetative season. In less species-rich grassland, GH and DH can efficiently collect high seed amounts of the fewer species present, even if implemented over smaller areas. 相似文献
115.
M. Andrew Stamper Michele M. Kittell Erin E. Patel Allison L. Corwin 《Journal of aquatic animal health》2013,25(3):111-116
Abstract Head and lateral line erosion syndrome (HLLES) is a common but very poorly understood disease of marine aquarium fish. One suspected etiology is the use of granulated activated carbon (GAC) to filter the water. Seventy-two ocean surgeons Acanthurus bahianus were distributed among three carbon-negative control systems and three GAC-treated systems such that each tank contained approximately the same total body mass. Each replicate system was made up of two 250-L circular tanks with a common filtration system (6 fish per tank, 12 fish per replicate system). The GAC-treated tanks were exposed to full-stream, extruded coconut shell activated carbon, which produced a mean total organic carbon content of 0.4 mg/L. The results of this study indicate that extruded coconut shell activated carbon filtering at full-stream rates can cause HLLES-type lesions in ocean surgeons. The HLLES developed exponentially over 15 d, beginning in the chin region. This was followed by pitting in the cheek region, which expanded until erosions coalesced. Once the carbon was discontinued, the processes reversed in a mean time of 49 d. As the lesions healed, they reverted from the coalesced to the pitted stage and then darkened before returning to normal. Received September 2, 2010; accepted March 20, 2011 相似文献
116.
Alberto Cesarani Salvatore Mastrangelo Michele Congiu Baldassare Portolano Giustino Gaspa Marco Tolone Nicolò P. P. Macciotta 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2023,140(1):28-38
The effects of inbreeding in livestock species breeds have been well documented and they have a negative impact on profitability. The objective of this study was to evaluate the levels of inbreeding in Sarda (SAR, n = 785) and Valle del Belice (VdB, n = 473) dairy sheep breeds and their impact on milk production traits. Two inbreeding coefficients (F) were estimated: using pedigree (FPED), or runs of homozygosity (ROH; FROH) at different minimum ROH lengths and different ROH classes. After the quality control, 38,779 single nucleotide polymorphisms remained for further analyses. A mixed-linear model was used to evaluate the impact of inbreeding coefficients on production traits within each breed. VdB showed higher inbreeding coefficients compared to SAR, with both breeds showing lower estimates as the minimum ROH length increased. Significant inbreeding depression was found only for milk yield, with a loss of around 7 g/day (for SAR) and 9 g/day (VdB) for a 1% increase of FROH. The present study confirms how the use of genomic information can be used to manage intra-breed diversity and to calculate the effects of inbreeding on phenotypic traits. 相似文献
117.
To identify hybrid-specific differences in developmental response to mechanical perturbation (MP), we compared the effects of stem flexure on several morphological and mechanical properties of two Populus trichocarpa Torr. & A. Gray x P. deltoides Bartr. ex Marsh. hybrids, 47-174 and 11-11. In response to the MP treatment, both hybrids exhibited a significant increase in radial growth, especially in the direction of the MP (47-174, P = 0.0001; 11-11, P = 0.002), and a significant decrease in height to diameter growth ratio (P = 0.0001 for both hybrids), suggesting that MP-treated stems are more tapered than control stems. A direct consequence of the MP-induced increase in radial growth was a significant increase in flexural rigidity (EI, N mm(2)) in stems of both hybrids (47-174, P = 0.0001; 11-11, P = 0.009). Both control and MP-treated stems of Hybrid 47-174 had significantly greater height to diameter ratios and EI values than the corresponding stems of Hybrid 11-11 (11-11 stem ratios and EI values were 85 and 76%, respectively, of those of 47-174). In Hybrid 47-174, Young's modulus of elasticity (E, N mm(-2)), a measure of stem flexibility, for MP-treated stems was only 80% of the control value (P = 0.0034), whereas MP had no significant effect on E of stems of Hybrid 11-11 (P = 0.2720). Differences in flexure response between the hybrids suggest that Hybrid 47-174 can produce a stem that is more tolerant of wind-induced flexure by altering both stem allometry and material properties, whereas Hybrid 11-11 relies solely on changes in stem allometry for enhanced stability under MP conditions. 相似文献
118.
Influence of ozone and nitrogen deposition on bark beetle activity under drought conditions 总被引:3,自引:0,他引:3
Michele Eatough Jones Timothy D. Paine Mark E. Fenn Mark A. Poth 《Forest Ecology and Management》2004,200(1-3):67-76
Four years of severe drought from 1999 through 2003 led to unprecedented bark beetle activity in ponderosa and Jeffrey pine in the San Bernardino and San Jacinto Mountains of southern California. Pines in the San Bernardino Mountains also were heavily impacted by ozone and nitrogenous pollutants originating from urban and agricultural areas in the Los Angeles basin. We studied bark beetle activity and bark beetle associated tree mortality in pines at two drought-impacted sites in the San Bernardino Mountains, one receiving high levels of atmospheric pollutants, and one with more moderate atmospheric input. We also investigated the effects of nitrogen addition treatments of 0, 50 and 150 kg N ha−1 year−1 at each site. Tree mortality and beetle activity were significantly higher at the high pollution site. Differences in beetle activity between sites were significantly associated with ozone injury to pines, while differences in tree mortality between sites were significantly associated with both ozone injury and fertilization level. Tree mortality was 9% higher and beetle activity 50% higher for unfertilized trees at the high pollution site compared to the low pollution site. Tree mortality increased 8% and beetle activity increased 20% under the highest rates of nitrogen additions at the low pollution site. The strong response in beetle activity to nitrogen additions at the low pollution site suggests that atmospheric nitrogen deposition increased tree susceptibility to beetle attack at the high deposition site. While drought conditions throughout the region were a major factor in decreased tree resistance, it appears that both ozone exposure and atmospheric nitrogen deposition further increased pine susceptibility to beetle attack. 相似文献
119.
Qingjiang Hou James Brandle Kenneth Hubbard Michele Schoeneberger Carlos Nieto Charles Francis 《Agroforestry Systems》2003,57(2):137-147
Root-pruning is generally recommended as an appropriate treatment to reduce competition for soil water and/or nutrients and suppression of crop yield in areas adjacent to windbreaks. Several recent studies suggest, however, that factors other than soil water might be causing yield reduction at the interface. For two consecutive years, we evaluated root-pruning effects on soil water at the windbreak/crop interface under both cropped (soybean [Glycine max (L) Merr.] variety Iroquois, 1997) and non-cropped (1998) conditions in Mead, Nebraska, USA. Volumetric soil water content near the windbreaks was systematically measured at various soil depths, distances from the windbreak, and windbreak exposures using Time Domain Reflectometry (TDR). Overall differences in soil water content between root-pruned and non-pruned plots in soybean were smaller in magnitude at all distances in both the west (windbreak on the east side) and the east (windbreak on the west side) exposures in 1997, compared with the non-cropped condition in the south exposure in 1998. With a soybean crop in 1997, volumetric soil water content in the east exposure averaged 2.3% greater in the top 30 cm of the soil profile at a distance of 0.75H (H = windbreak height) into the field from the windbreak when compared to the non-pruned treatment. In the west exposure, however, the differences were undetectable at corresponding distance and depth. The increase in soybean yield in root-pruned plots corresponded well with the observed differences in soil water content at various distances, especially in the east exposure. Under a non-cropped condition in 1998, soil water content in the root-pruned plots was significantly greater than the non-pruned plots in the top 45-cm profile, averaging 3.3% at 0.75H and 2.2% at 1.0H. Beyond 1.0H, the increase was not significant. These results agree with the previously reported range of crop yield suppression near windbreaks, indicating that soil water competition between the crop and windbreak is highly related to, and probably plays a leading role in yield suppression within the competition zone.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
120.
Perugini M Visciano P Manera M Turno G Lucisano A Amorena M 《Journal of agricultural and food chemistry》2007,55(5):2049-2054
Polycyclic aromatic hydrocarbons (PAHs) were determined by an HPLC method with fluorescence detection in bivalves (Mitylus galloprovincialis), cephalopods (Todarodes sagittatus), crustaceans (Aristeus antennatus), and fish (Mullus surmeletus, Scomber scombrus, Micromesistius poutassou, and Merluccius merluccius) caught in the Gulf of Naples (Tyrrhenian Sea, Italy). Anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, and benzo(k)fluoranthene were detected, at different concentrations, in all of the examined marine organisms, whereas benzo(a)pyrene, dibenz(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3-cd)pyrene were found only in Mediterranean mussels. Of mussels collected in winter 71.43% exceeded the maximum residual levels (MRL) fixed for the benzo(a)pyrene in European Regulation 208/2005/EC, whereas all samples collected in summer reported values lower than this limit. In comparison to the other marine organisms, the mussels showed the highest PAH concentrations (p < 0.01). Fish showed total PAH levels lower than those of cephalopods and, in particular, European hake showed the lowest values (6.06 ng/g of fresh weight). 相似文献