全文获取类型
收费全文 | 377篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
林业 | 51篇 |
农学 | 9篇 |
基础科学 | 1篇 |
89篇 | |
综合类 | 35篇 |
农作物 | 22篇 |
水产渔业 | 16篇 |
畜牧兽医 | 123篇 |
园艺 | 17篇 |
植物保护 | 35篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 12篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 23篇 |
2013年 | 13篇 |
2012年 | 29篇 |
2011年 | 33篇 |
2010年 | 21篇 |
2009年 | 24篇 |
2008年 | 29篇 |
2007年 | 30篇 |
2006年 | 27篇 |
2005年 | 23篇 |
2004年 | 11篇 |
2003年 | 15篇 |
2002年 | 19篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有398条查询结果,搜索用时 15 毫秒
391.
Kim N Huang SN Williams JS Li YC Clark AB Cho JE Kunkel TA Pommier Y Jinks-Robertson S 《Science (New York, N.Y.)》2011,332(6037):1561-1564
The ribonuclease (RNase) H class of enzymes degrades the RNA component of RNA:DNA hybrids and is important in nucleic acid metabolism. RNase H2 is specialized to remove single ribonucleotides [ribonucleoside monophosphates (rNMPs)] from duplex DNA, and its absence in budding yeast has been associated with the accumulation of deletions within short tandem repeats. Here, we demonstrate that rNMP-associated deletion formation requires the activity of Top1, a topoisomerase that relaxes supercoils by reversibly nicking duplex DNA. The reported studies extend the role of Top1 to include the processing of rNMPs in genomic DNA into irreversible single-strand breaks, an activity that can have distinct mutagenic consequences and may be relevant to human disease. 相似文献
392.
Bernard Godon Marie-Pierre Leblanc Yves Popineau Ateliers et Chantiers de Bretagne 《Plant foods for human nutrition (Dordrecht, Netherlands)》1983,33(2-3):161-168
A new small scale device for wheat gluten separation is described and the results of the first experiments on the influence of extraction conditions on different flours are reported. 相似文献
393.
Objective To characterize the acute cardiopulmonary effects of severe hemorrhage in anesthetized horses. Study design Prospective experimental study. Animals Three geldings and six mares, aged 14.4 ± 2.7 years, weighing 486 ± 41 kg (range: 425–550 kg). Methods Horses were anesthetized using xylazine, guaifenesin, ketamine and halothane or isoflurane. Cardiovascular variables, hematocrit, total solids, capillary refill time (CRT) and color of mucous membranes were measured as blood was collected from the carotid artery into sterile plastic bags. Arterial blood gas analysis was also performed. Results The average amount of blood collected from these horses was (mean ± SD) 53 ± 4.8 mL kg?1 bodyweight (range: 23–32 kg) over 39 ± 4 minutes. Hematocrit decreased from 38 ± 3 to 32 ± 2% after induction of anesthesia and did not change significantly over the period of blood loss. Total solids decreased significantly after induction of anesthesia, and over the period of blood loss. Systolic, mean, diastolic and pulse pressures decreased as blood was lost. Heart rate did not change significantly. Capillary refill time increased from 1.6 ± 0.4 seconds to 4.8 ± 1.3 seconds as blood loss increased. Mucous membrane color deteriorated progressively. Arterial PO2 decreased significantly over the period of blood loss. Conclusions Hematocrit and heart rate do not change significantly during acute severe hemorrhage in the anesthetized horse. Arterial blood pressure, pulse pressure and PaO2 decrease as blood loss increases. Changes in mucous membrane color and CRT also occur as blood loss increases. Clinical relevance During severe hemorrhage in the inhalant‐anesthetized horse, both heart rate and hematocrit remain unchanged. Blood pressure decreases and changes in arterial PO2 correlate most strongly with volume of blood lost. 相似文献
394.
Troy J. Ostmeyer Somayanda M. Impa Scott R. Bean Rajveer Dhillon Chad Hayes Glen Ritchie Antonio R. Asebedo Yves Emendack S. V. Krishna Jagadish 《植物养料与土壤学杂志》2023,186(6):647-660
Background
The correct rate and timing of nitrogen (N) has the potential to improve sorghum productivity through modified grain yield components and quality. The impacts of in-season split application of N have little documentation.Aim
An experiment was conducted to determine the optimum rate and timing of N to relate vegetative indices that govern nitrogen use efficiency and to maximize grain yield and quality under different soil types.Methods
Pioneer 86P20 was grown in three environments on two different soil types following a completely randomized block design with nine N application treatments. Treatments included differing N rates applied at critical developmental stages of sorghum (planting, panicle initiation, and booting), accompanied with high temporal aerial phenotyping.Results
Opportunities to increase grain protein content while using split N applications were observed, with panicle initiation identified as a critical developmental stage. In-season split application of N enhances grain yield under low soil mineral N. Split application of 31 kg N ha−1 each at the time of planting, panicle initiation, and booting emerged as optimum N treatment to increase protein content in sorghum. Vegetative indices, that is, normalized difference vegetation index and normalized difference red edge index are capable of predicting grain yield and protein content, respectively. Intra-panicle grain numbers and weights were altered significantly at different portions within panicles, with an opportunity to enhance yield potential at the bottom portion. The strong stay-green trait in this hybrid locked a large proportion of nitrogen in the leaves, which warrants the need for balancing stay-green and senescence in sorghum improvement programs.Conclusions
Findings highlight that in grain sorghum remobilization of residual leaf N into grain is a target to increase yield and grain quality. An optimized stay-green trait balanced with senescence is recommended for enhancing sorghum yield potential. 相似文献395.
Relationship between biochemical markers and radiographic scores in the evaluation of the osteoarticular status of Warmblood stallions 总被引:1,自引:0,他引:1
Denis Verwilghen Valeria Busoni Monika Gangl Thierry Franck Jean-Philippe Lejeune Laurent Vanderheyden Johann Detilleux Sigrid Grulke Michelle Deberg Yves Henrotin Didier Serteyn 《Research in veterinary science》2009,87(2):319-328
Establishing the osteoarticular status of the horse is often performed by means of radiological screening of the animals. Widespread blood sampling could reveal to be an interesting alternative to this procedure which is time consuming and sometimes technically difficult. The aim of this study was to investigate the relationship between the radiological status of the horses and the levels of biochemical markers of cartilage degradation and synovial inflammation. A specific radiological scoring and classification system was therefore developed and applied on 63 stallions presented for studbook admission. Additionally, groups of horses were established according to the occurrence of osteochondrosis, degenerative joint disease and distal interphalangeal joint effusion. Insulin growth factor-I, myeloperoxidases, Coll2-1 and Coll2-1NO2 were used as blood markers. The combination of the blood parameters did not seem to correlate with the used scoring system. Coll2-1NO2 levels however tended to increase with poorer radiological class and this could therefore potentially be a useful predictor of the osteoarticular status in the horse. Coll2-1 levels were significantly higher in the degenerative joint disease group. A high percentage of horses with distal interphalangeal joint effusion was present in this study and was associated with decreased IGF-I and increased Coll2-1 levels. 相似文献
396.
Yves PS Moens DVM PD PhD Diplomate ECVAA Peter Gootjes† Ing Jean-Claude Ionita‡ DVM Erkki Heinonen§ Lic Tech PhD & Urs Schatzmann‡ DVM PhD Diplomate ECVAA 《Veterinary anaesthesia and analgesia》2009,36(3):209-219
Objective To remodel and validate commercially available monitors and their Pitot tube-based flow sensors for use in large animals, using in vitro techniques.
Study design Prospective, in vitro experiment.
Methods Both the original and the remodelled sensor were studied with a reference flow generator. Measurements were taken of the static flow-pressure relationship and linearity of the flow signal. Sensor airway resistance was calculated. Following recalibration of the host monitor, volumes ranging from 1 to 7 L were generated by a calibration syringe, and bias and precision of spirometric volume was determined. Where manual recalibration was not available, a conversion factor for volume measurement was determined. The influence of gas composition mixture and peak flow on the conversion factor was studied.
Results Both the original and the remodelled sensor showed similar static flow–pressure relationships and linearity of the flow signal. Mean bias (%) of displayed values compared with the reference volume of 3, 5 and 7 L varied between −0.4% and +2.4%, and this was significantly smaller than that for 1 L (4.8% to +5.0%). Conversion factors for 3, 5 and 7 L were very similar (mean 6.00 ± 0.2, range 5.91–6.06) and were not significantly influenced by the gas mixture used. Increasing peak flow caused a small decrease in the conversion factor. Volume measurement error and conversion factors for inspiration and expiration were close to identity.
Conclusion The combination of the host monitor with the remodelled flow sensor allowed accurate in vitro measurement of flows and volumes in a range expected during large animal anaesthesia.
Clinical relevance This combination has potential as a reliable spirometric monitor for use during large animal anaesthesia. 相似文献
Study design Prospective, in vitro experiment.
Methods Both the original and the remodelled sensor were studied with a reference flow generator. Measurements were taken of the static flow-pressure relationship and linearity of the flow signal. Sensor airway resistance was calculated. Following recalibration of the host monitor, volumes ranging from 1 to 7 L were generated by a calibration syringe, and bias and precision of spirometric volume was determined. Where manual recalibration was not available, a conversion factor for volume measurement was determined. The influence of gas composition mixture and peak flow on the conversion factor was studied.
Results Both the original and the remodelled sensor showed similar static flow–pressure relationships and linearity of the flow signal. Mean bias (%) of displayed values compared with the reference volume of 3, 5 and 7 L varied between −0.4% and +2.4%, and this was significantly smaller than that for 1 L (4.8% to +5.0%). Conversion factors for 3, 5 and 7 L were very similar (mean 6.00 ± 0.2, range 5.91–6.06) and were not significantly influenced by the gas mixture used. Increasing peak flow caused a small decrease in the conversion factor. Volume measurement error and conversion factors for inspiration and expiration were close to identity.
Conclusion The combination of the host monitor with the remodelled flow sensor allowed accurate in vitro measurement of flows and volumes in a range expected during large animal anaesthesia.
Clinical relevance This combination has potential as a reliable spirometric monitor for use during large animal anaesthesia. 相似文献
397.
Isabelle Iff Dr med vet Diplomate ECVAA Sonja Franz† Dr med vet & Yves Moens Dr med vet PhD Diplomate ECVAA 《Veterinary anaesthesia and analgesia》2009,36(5):495-501
ObjectiveTo measure the pressure profile during caudal extradural puncture and subsequent extradural anaesthesia in cattle and to investigate the presence of extradural pressure waves.Study designProspective experimental study.AnimalsEleven cattle aged 4.1 ± 2.5 years (range 0.8 to 8.8 years), with a body weight of 613 ± 162 kg (range 302–840 kg).MethodsCaudal extradural puncture was performed. To measure the extradural pressure profile, the needle was connected to an electronic pressure transducer placed at the height of the base of the tail. The pressure profile was recorded for 3 minutes following extradural puncture. Lack of resistance to injection of saline was assessed. One minute and 10 minutes after extradural anaesthesia with procaine extradural pressure was recorded. Correct extradural needle placement was assessed by clinical response.ResultsThree minutes after extradural puncture the median pressure was ?16 (range ?25 to 25) mmHg. Pressure in the extradural space 1 minute after the lack of resistance, 3 seconds after injection, and 10 minutes after injection was ?15 (?24 to 33) mmHg, 8 (?17 to 84) mmHg, and ?7 (?25 to 27) mmHg respectively. Pressure waves were visible after puncture, after lack of resistance, 3 seconds and 10 minutes after injection, in 4, 6, 8 and 7 cattle respectively. Pressure after testing lack of resistance, after the injection of local anaesthetic, as well as at the end of the measurement, period was significantly higher than baseline. All cattle showed clinical signs indicative of successful extradural needle placement.Conclusion and clinical relevance Extradural pressure was sub-atmospheric in 82% of the animals. Pressure waves were not consistently present before or after extradural injection, which limits their usefulness to confirm correct extradural needle placement. Extradural pressures increase significantly after injection of local anaesthetic solution. However, the clinical significance of the increase in extradural pressures was not clear. 相似文献
398.
Mertens Arne Bawin Yves Vanden Abeele Samuel Kallow Simon Swennen Rony Vu Dang Toan Vu Tuong Dang Minh Ho Thi Panis Bart Vandelook Filip Janssens Steven B. 《Genetic Resources and Crop Evolution》2022,69(7):2515-2534
Genetic Resources and Crop Evolution - Collection and storage of crop wild relative (CWR) germplasm is crucial for preserving species genetic diversity and crop improvement. Nevertheless, much of... 相似文献