全文获取类型
收费全文 | 1033篇 |
免费 | 64篇 |
专业分类
林业 | 48篇 |
农学 | 25篇 |
基础科学 | 2篇 |
134篇 | |
综合类 | 89篇 |
农作物 | 30篇 |
水产渔业 | 41篇 |
畜牧兽医 | 677篇 |
园艺 | 23篇 |
植物保护 | 28篇 |
出版年
2023年 | 16篇 |
2022年 | 16篇 |
2021年 | 20篇 |
2020年 | 34篇 |
2019年 | 36篇 |
2018年 | 28篇 |
2017年 | 20篇 |
2016年 | 26篇 |
2015年 | 28篇 |
2014年 | 24篇 |
2013年 | 44篇 |
2012年 | 70篇 |
2011年 | 86篇 |
2010年 | 34篇 |
2009年 | 37篇 |
2008年 | 68篇 |
2007年 | 81篇 |
2006年 | 75篇 |
2005年 | 63篇 |
2004年 | 62篇 |
2003年 | 74篇 |
2002年 | 58篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1970年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有1097条查询结果,搜索用时 31 毫秒
991.
Tolina T. Son DVM Lisa Thompson DVM DACVECC Sergi Serrano LV DACVECC Ravi Seshadri DVM DACVECC DAVBP 《Journal of Veterinary Emergency and Critical Care》2010,20(4):426-435
Objective – To evaluate clinical characteristics and outcomes of cats undergoing surgical intervention in the course of treatment for severe acute pancreatitis. Design – Retrospective observational study from 2003 to 2007 with a median follow‐up period of 2.2 years (range 11 d–5.4 y) postoperatively. Setting – Private referral veterinary center. Animals – Eight cats. Interventions – None. Measurements and Main Results – Quantitative data included preoperative physical and clinicopathologic values. Qualitative parameters included preoperative ultrasonographic interpretation, perioperative and intraoperative feeding tube placement, presence of free abdominal fluid, intraoperative closed suction abdominal drain placement, postoperative complications, microbiological culture, and histopathology. Common presenting clinical signs included lethargy, anorexia, and vomiting. Leukocytosis and hyponatremia were present in 5 of 8 cats. Hypokalemia, increased total bilirubin, and hyperglycemia were present in 6 of 8 cats. Elevated alanine aminotransferase and aspartate transferase were present in all cats. Surgery for extrahepatic biliary obstruction was performed in 6 cats, pancreatic abscess in 3 cats, and pancreatic necrosis in 1 cat. Six of the 8 cats survived. Five of the 6 cats that underwent surgery for extrahepatic biliary obstruction and 1 cat that underwent pancreatic necrosectomy survived. All 5 of the cats with extrahepatic biliary obstruction secondary to pancreatitis survived. The 2 nonsurvivors included a cat with a pancreatic abscess and a cat with severe pancreatitis and extrahepatic biliary obstruction secondary to a mass at the gastroduodenal junction. Postoperative complications included progression of diabetes mellitus, septic peritonitis, local gastrostomy tube stoma inflammation, local gastrostomy tube stoma infection, and mild dermal suture reaction. Conclusion – Cats with severe acute pancreatitis and concomitant extrahepatic biliary obstruction, pancreatic necrosis, or pancreatic abscesses may benefit from surgical intervention. Cats with extrahepatic biliary obstruction secondary to severe acute pancreatitis may have a good prognosis. 相似文献
992.
Jaramillo C Ochoa D Contreras L Pagani M Carvajal-Ortiz H Pratt LM Krishnan S Cardona A Romero M Quiroz L Rodriguez G Rueda MJ de la Parra F Morón S Green W Bayona G Montes C Quintero O Ramirez R Mora G Schouten S Bermudez H Navarrete R Parra F Alvarán M Osorno J Crowley JL Valencia V Vervoort J 《Science (New York, N.Y.)》2010,330(6006):957-961
Temperatures in tropical regions are estimated to have increased by 3° to 5°C, compared with Late Paleocene values, during the Paleocene-Eocene Thermal Maximum (PETM, 56.3 million years ago) event. We investigated the tropical forest response to this rapid warming by evaluating the palynological record of three stratigraphic sections in eastern Colombia and western Venezuela. We observed a rapid and distinct increase in plant diversity and origination rates, with a set of new taxa, mostly angiosperms, added to the existing stock of low-diversity Paleocene flora. There is no evidence for enhanced aridity in the northern Neotropics. The tropical rainforest was able to persist under elevated temperatures and high levels of atmospheric carbon dioxide, in contrast to speculations that tropical ecosystems were severely compromised by heat stress. 相似文献
993.
Lisa M. Tomkins Peter C. Thomson Paul D. McGreevy 《Journal of Veterinary Behavior: Clinical Applications and Research》2010,5(5):247-255
Motor laterality in potential guide dogs (n = 113) was determined using two methods: the Kong? Test (the current benchmark test) and our innovation, a First-stepping Test. Kong? studies record paw use during foraging from a rubber cylinder. However, motivation to feed varies markedly among dogs and breeds, and the test comprises 50 observations which for a single dog can take up to 4 hours to collect. The First-stepping Test bypasses hunger, and simply records the first foot advanced after standing with both forelegs level. In contrast to the Kong? Test, it allows 50 observations to be gathered in 20 minutes. The findings of the current study indicate that lateralized behavior in the domestic dog is strongly task-dependent. The First-stepping Test revealed more significant paw preferences (PPs) than the Kong? Test (76.1% vs. 52.2%). A significant right population bias (P = 0.036) was revealed using this novel test, whereas there was no bias in the direction of laterality observed using the Kong? Test (P = 0.30). Instead, there was a significant population bias for the category of ambidextrous PP using the Kong? (P = 0.005). Strength of laterality (regardless of direction) was significantly high in the First-stepping Test (P < 0.001), but only weak PPs were observed for the Kong? Test (P = 0.65). Measures of laterality from the First-stepping Test were not influenced by dog factors, whereas age, breed, and sex of the dog were significantly associated with several laterality measures during the Kong? Test. The occurrence of using both paws simultaneously to either hold the Kong?, or to step-off by means of jumping, was associated with a decrease in lateral strength for both tests. The First-stepping Test was repeatable, and the intraobserver (κ = 0.988) and interobserver (κ = 0.975) reliabilities were high. It offers a simple, quick and, when compared with the Kong? Test, a more discriminative method of determining PP that is less influenced by dog factors. 相似文献
994.
Chiara Lanzanova Maria Gabriella Giuffrida Mario Motto Cristina Baro Guenter Donn Hans Hartings Elisabetta Lupotto Maria Careri Lisa Elviri Carlotta Balconi 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(3):471-482
In maize endosperm, a cytosolic albumin, b-32, with a molecular weight of 32 kDa is synthesised in temporal and quantitative
coordination with the deposition of storage proteins. This protein has homology with several previously characterised Ribosome-Inactivating
Proteins (RIPs). To verify if the maize plant expressing b-32 in various tissues has an increased tolerance to fungal pathogens,
transgenic plants were obtained through genetic transformation using a chimeric gene containing the b-32 coding sequence downstream of a constitutive 35SCaMV promoter. A set of four independent homozygous progenies expressing b-32, were selected for a detailed analysis of b-32 expression
in leaves and for pathogenicity tests. A differential b-32 content in leaf protein extracts was recorded in the transgenic
progenies. Proteomic investigations on protein leaf extracts were carried out; the overlapping of the two-dimensional electrophoresis
maps demonstrated the presence in a transgenic progeny, of additional spots, identified as b-32 and as a protein for herbicide
resistance, in comparison to the negative control. Transgenic progenies were tested in bioassays to evaluate the response
to Fusarium attack in leaf tissues. Preliminary experiments supported the choice of bioassay parameters for a reliable evaluation
of transgenic progenies. The negative control was most susceptible to Fusarium verticillioides attack, compared to transgenic progenies. The data obtained indicate that maize b-32 was an effective antifungal protein
by reducing Fusarium infection progression. Additionally, the reduction in Fusarium attack symptoms was related to b-32 concentration
in leaf tissues. 相似文献
995.
996.
Nahla Bassil Amira Bidani Kim Hummer Lisa J. Rowland Jim Olmstead Paul Lyrene Christopher Richards 《Genetic Resources and Crop Evolution》2018,65(3):939-950
Wild species representatives from Northwestern, Central and Southern Florida, and neighboring U.S. states were collected in multiple United States Department of Agriculture (USDA) exploration expeditions and are being preserved at the USDA, Agricultural Research Service, National Clonal Germplasm Repository in Corvallis, Oregon. Germplasm from these southeastern regions of North America is particularly vulnerable to loss in the wild due to encroachment of human development in key habitats and biotic and abiotic stresses from climate change. Fourteen simple sequence repeats (SSRs), previously developed from the highbush blueberry (Vaccinium corymbosum) cultivar ‘Bluecrop’, were used to estimate genetic diversity and genetic differentiation of 67 diploid individuals from three species, including 19 V. elliottii, 12 V. fuscatum, and 35 V. darrowii accessions collected throughout the species’ ranges. Results from our analyses indicated that the samples from each species could be reliably resolved using genetic distance measures with ordination and neighbor joining approaches. In addition, we estimated admixture among these species by using Bayesian assignment tests, and were able to identify a mis-labeled accession of V. darrowii ‘Johnblue’, two mis-classified accessions (CVAC 735.001 and CVAC 1223.001), and four accessions of previously undescribed hybrid origin (CVAC 734.001, CVAC 1721.001, CVAC 1741.001, and Florida 4B CVAC 1790). Allele composition at the 14 SSRs confirmed that Florida 4B CVAC 1790, the donor of low chilling for the southern highbush blueberry, was the critical parent of US 74. Genetic diversity assessment and identification of these wild accessions are crucial for optimal germplasm management and expand opportunities to utilize natural variation in breeding programs. 相似文献
997.
The effect of crate height on the behavior of female turkeys during commercial pre‐slaughter transportation 下载免费PDF全文
Guido Di Martino Katia Capello Anna Lisa Stefani Luca Tripepi Angelica Garbo Marina Speri Matteo Trolese Michele Brichese Stefano Marangon Lebana Bonfanti 《Animal Science Journal》2017,88(10):1651-1657
Limited information is available on suitable height of transport crates for turkeys. We compared behaviors and physiological indicators of four groups of 10 female turkeys each confined in either conventional (38.5 cm height) or experimental (77 cm height) crates during six commercial pre‐slaughter transportations for 86 km (76 ± 4 min) along two tracts with one‐lane streets, crossroads, bends, roundabouts (S1 and S2) and a highway tract (H) between S1 and S2. Only 36% of birds in the higher crates maintained a standing position. In conventional versus experimental crates, the frequency of rising attempts was five/bird/hour versus less than one/bird/hour, while wing flapping was seven/bird/hour versus 20/bird/hour, and balance loss was one versus four/bird/hour. The behaviors of both groups differed significantly according to the route tract, with a lower frequency of stress‐related behaviors at H. No scratches, fractures or hematomas were detected in any birds after transportation. Crate height had no significant effect on hemato‐biochemical markers. These results suggest that crates enabling a standing position may increase potentially dangerous behaviors. Moreover, busy and curvy routes should be avoided, as they may contribute to increasing the frequency of stress‐related behaviors. 相似文献
998.
Duana McBride Anthea L. Raisis Giselle Hosgood Lisa Smart 《Veterinary anaesthesia and analgesia》2017,44(3):444-451
Objective
To determine the cardiovascular and acid-base effects of 6% hydroxyethyl starch (HES) 130/0.4 and 0.9% sodium chloride (NaCl) administered to anaesthetized greyhounds with haemorrhagic shock.Study design
Prospective, experimental, complete randomized block design.Animals
Twelve healthy adult greyhounds.Methods
After 60 minutes of isoflurane anaesthesia, 48 mL kg?1 of blood was removed to induce hypotension. Dogs were randomized to receive either 20 mL kg?1 of HES 130/0.4 or 80 mL kg?1 of 0.9% NaCl over 20 minutes. Haemoglobin, arterial and central venous blood gas and electrolytes, lactate, mean arterial pressure (MAP) and cardiac index were measured at: T0, 60 minutes after induction of anaesthesia, immediately prior to blood removal; T1, immediately after blood removal; T2, immediately after fluid administration; and T3, 40 minutes after fluid administration. Oxygen extraction ratio (O2ER) was calculated at each sample time.Results
O2ER increased at T1 and decreased at T2 and T3, with no difference between the two groups. Dogs administered HES 130/0.4 had higher lactate at T2 [mean (95% confidence interval) 1.3 (0.8–1.9) mmol L?1] than dogs administered 0.9% NaCl [0.8 (0.5–1.1) mmol L?1]; p = 0.045. Dogs administered HES 130/0.4 had a higher MAP at T3 [88 (74–102) mmHg] than dogs administered 0.9% NaCl [69 (60–79) mmHg]; p = 0.019. Dogs administered 0.9% NaCl were more acidaemic at T2 and T3, including higher hydrogen ion, lower bicarbonate, lower base excess and higher chloride concentrations.Conclusion
and clinical relevance The effect of 20 mL kg?1 of HES 130/0.4 on shock, as measured by O2ER, was no different than that of 80 mL kg?1 of 0.9% NaCl in dogs under general anaesthesia. Acidaemia in the NaCl group is likely attributable to hyperchloraemic metabolic acidosis from the larger volume administered. 相似文献999.
1000.