全文获取类型
收费全文 | 1175篇 |
免费 | 73篇 |
国内免费 | 1篇 |
专业分类
林业 | 97篇 |
农学 | 30篇 |
基础科学 | 6篇 |
225篇 | |
综合类 | 215篇 |
农作物 | 33篇 |
水产渔业 | 100篇 |
畜牧兽医 | 435篇 |
园艺 | 33篇 |
植物保护 | 75篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 9篇 |
2021年 | 18篇 |
2020年 | 33篇 |
2019年 | 25篇 |
2018年 | 30篇 |
2017年 | 26篇 |
2016年 | 30篇 |
2015年 | 23篇 |
2014年 | 40篇 |
2013年 | 59篇 |
2012年 | 73篇 |
2011年 | 112篇 |
2010年 | 60篇 |
2009年 | 44篇 |
2008年 | 85篇 |
2007年 | 80篇 |
2006年 | 81篇 |
2005年 | 67篇 |
2004年 | 60篇 |
2003年 | 65篇 |
2002年 | 57篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 16篇 |
1998年 | 19篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 9篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1971年 | 2篇 |
1916年 | 2篇 |
1896年 | 1篇 |
1885年 | 1篇 |
1883年 | 2篇 |
排序方式: 共有1249条查询结果,搜索用时 15 毫秒
1.
Lactate Kinetics in veterinary Critical Care: A Review 总被引:3,自引:0,他引:3
Michael S. Lagutchik DVM Gregory K. Ogilvie DVM Wayne E. Wingfield MS DVM Timothy B. Hackett DVM MS 《Journal of Veterinary Emergency and Critical Care》1996,6(2):81-95.
Elevation in blood lactate concentration, with or without accompanying metabolic acidosis, is a hallmark finding in patients with circulatory compromise, and is also consistently noted in other conditions affecting critically ill or injured individuals. Little is reported in a veterinary literature regarding lactate measurement in the emergency and critical care setting, despite impressive reports of the clinical usefulness of lactate measurement in people. The purpose of this article is to review lactate kinetics and the clinical utility of lactate measurement. Limitations to lactate evaluation will also be discussed. 相似文献
2.
Deborah R. Van Pelt DVM MS Wayne E. Wingfield MS DVM Timothy B. Hackett DVM Linda G Martin DVM 《Journal of Veterinary Emergency and Critical Care》1993,3(2):63-70
Over the past several decades, recognition of acute respiratory failure as the cause of death in patients suffering from various clinical conditions has prompted aggressiv investigation into the area of respiratory physiology and supportive respiratory care. With the evolution of emergency medicine and critical care services in both human and veterinary medicine, many patients previously considered unsalvageable due to the severity of their underlying disease are now being resuscitated and successfully supported, creating a new population of critically ill patients. Where only a decade ago these patients would have succumbed to their underlying disease, they now survive long enough to manifest the complications of shock and tissue injury in the form of acute respiratory failure. Investigation into the pathophysiology and treatment of this acute respiratory distress syndrom (ARDS) has facilitated increased clinical application of respiratory theerapy and machanical ventilation.1 The purpose of this paper is to provide a basic review of respiratory mechanics and the pathophysiology of hypoxemia as they relate to airway pressure therapy in veterinary patients and to review the use of airway pressure therapy in veterinary patients This paper is divided into two parts; part I reviews respiratory mechanics and hypoxemia as they apply to respiratory therapy, while part II deals specifically with airway pressure therapy andits use in clinical cases. 相似文献
3.
Application of Airway Pressure Therapy in Veterinary Critical Care: Part II: Airway Pressure Therapy
Deborah R. Van Pelt DVM MS Wayne E. Wingfield MS DVM Timothy B. Hackett DVM Linda G. Martin DVM 《Journal of Veterinary Emergency and Critical Care》1993,3(2):71-81
As the specialties of emergency medicine and critical care have grown and evolved in both human and veterinary medicine, so has the need for more advanced care of patients with primary lung disease. Treatment of acute respiratory failure has been the focus of several articles in the human medical literature of the past few years.1,8 This paper deals with airway pressure therapy and its application in cases of acute respiratory failure in veterinary medicine. The reader is referred to part I of this paper for a reveiw of respiratory mechanics and hypoxemia as they apply to respiratory therapy. 相似文献
4.
Hong Li Donal O'Toole Okjin Kim J Lindsay Oaks Timothy B Crawford 《Journal of veterinary diagnostic investigation》2005,17(2):171-175
A malignant catarrhal fever (MCF)-like disease was induced experimentally in 3 sheep after aerosol inoculation with ovine herpesvirus-2 (OvHV-2). Each of 3 OvHV-2-negative sheep was nebulized with 2 ml of nasal secretions containing approximately 3.07 X 10(9) OvHV-2 DNA copies from a sheep experiencing an intensive viral-shedding episode. Ovine herpesvirus-2 DNA became detectable by polymerase chain reaction in the peripheral blood leukocytes of all 3 sheep within 3 days, and all 3 seroconverted between 6 and 8 days postinfection (PI). The sheep developed clinical signs, with copious mucopurulent nasal discharge and fever around 14 days PI. One of the 3 clinically affected sheep was euthanized at 18 days PI. Major lesions at necropsy were multifocal linear erosions and ulcers in mucosa of the cheeks, tongue, pharynx, and proximal esophagus and mild disseminated pneumonia. Microscopically, there was extensive moderate superficial histiocytic-lymphocytic rhinitis with epithelial dissociation and degeneration. Moderate multifocal histiocytic bronchointerstitial pneumonia was associated with loss of terminal bronchiolar epithelium. Lymphocytic vasculitis was present only in the lung. The remaining 2 sheep recovered clinically, approximately 25 days PI. The study revealed that clinical signs and lesions resembling MCF can develop when uninfected sheep are exposed to a high dose of aerosolized OvHV-2. 相似文献
5.
Francesco Faggioli Graziella Pasquini Valentina Lumia Gaetano Campobasso Timothy L. Widmer Paul C. Quimby Jr 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(4):353-360
In the United States, yellow starthistle (Centaurea solstitialis) is an annual invasive weed with Mediterranean origins. Malformed plants displaying witches' broom, fasciations, abortion of buds and flower virescence symptoms were observed in central Italy. Attempts to transmit the causal agent from the natural yellow starthistle host to periwinkle by grafting, resulted in typical symptoms of a phytoplasma, i.e. yellowing and shortening of internodes. The detection of phytoplasmas was obtained from both symptomatic yellow starthistle and periwinkle by the specific amplification of their 16S-23S rRNA genes. PCR amplification of extracted DNA from symptomatic plant samples gave a product of expected size. Asymptomatic plants did not give positive results. An amplicon obtained by direct PCR with universal primers P1/P7 was cloned and sequenced. The homology search using CLUSTALW program showed more than 99% similarity with Illinois elm yellows (ILEY) phytoplasma from Illinois (United States) and 97% with Brinjal little leaf (BLL) phytoplasma from India. Digestion of the nested-PCR products with restriction enzymes led to restriction fragment length polymorphism patterns referable to those described for phytoplasmas belonging to the clover proliferation (16S-VI) group. Since this is a previously undescribed disease, the name Centaurea solstitialis virescence has been tentatively assigned to it. This is a new phytoplasma with closest relationships to ILEY and BLL, but distinguishable from them on the basis of 16S rDNA homology, the different associated plant hosts and their geographical origin. 相似文献
6.
7.
Booker CW Abutarbush SM Schunicht OC Jim GK Perrett T Wildman BK Guichon PT Pittman TJ Jones C Pollock CM 《Veterinary therapeutics : research in applied veterinary medicine》2007,8(3):183-200
The purpose of this study was to determine the efficacy and cost-effectiveness of tulathromycin (DRAX) versus tilmicosin (MIC) or oxytetracycline (TET) as a metaphylactic antimicrobial in feedlot calves. Calves that received DRAX had significantly (P<.05) lower initial undifferentiated fever (UF) treatment and relapse rates; lower overall chronicity, overall mortality, and cause-specific mortality rates; higher average daily gains; and improved quality grades. However, calves that received DRAX also had poorer (P<.05) yield grades compared with calves that received MIC or TET and worse feed conversion compared with calves that received MIC. Net advantages in the DRAX group were 3.79CanDollars/animal and 16.96CanDollars/animal compared with the MIC and TET groups, respectively. Based on these results, DRAX is a more efficacious and cost-effective metaphylactic antimicrobial than MIC or TET in feedlot calves at ultra-high risk of developing UF. In addition, this study presents a comparison between two methods ("deads out" and "deads in") of calculating feedlot performance variables. 相似文献
8.
9.
10.
The use of saline waters is an option for the irrigation of salt tolerant ornamentals as competition for high quality water increases. However, despite the importance of ornamental shrubs in Mediterranean areas, salt tolerance of such species has received little attention. The aims of our investigation were to quantify the growth response and any injury symptom of 12 widely cultivated ornamental shrubs to irrigation with saline water and to investigate any possible relation with the concentration of Na+ and Cl− in the plants. Species were irrigated with different salinities (10, 40, and 70 mM NaCl) for a 120-day period. At the end of salt treatment, plants were sampled and dry biomass recorded; the relative growth rate (RGR) was also calculated. Root and leaf samples from each species were used to evaluate Na+, K+ and Cl− concentrations. Growth rates were significantly reduced in Cotoneaster lacteus, Grevillea juniperina and Pyracantha ‘Harlequin’, which also showed the highest percentage of necrotic leaves. The increasing external NaCl lead to an increase of Na+ and Cl− in roots and leaves of the different species, although less Na+ was accumulated than Cl−: growth reduction well correlated with the concentration of Cl− and/or Na+ in the leaves. The most sensitive species (i.e. C. lacteus, G. juniperina and Pyracantha ‘Harlequin’) had high concentrations of Na+ and/or Cl− in their leaves and also showed a decrease in their leaf K+/Na+ ratios. Even though other species (i.e. Bougainvillea glabra, Ceanothus thyrsiflorus, Leptospermum scoparium, Leucophyllum frutescens and Ruttya fruticosa) demonstrated a high ion concentration in their leaves, they could be considered relatively salt tolerant as there was little growth reduction and few symptoms of injury in the leaves. In some other cases (i.e. Cestrum fasciculatum, Escallonia rubra and Viburnum lucidum) the observed tolerance was related to higher ion concentration in the roots compared to the leaves, probably indicative of a limited transport to the shoots. Only in Eugenia myrtifolia was the absence of symptoms associated with a limited Na+ and Cl− uptake from the rhizosphere. 相似文献