全文获取类型
收费全文 | 3143篇 |
免费 | 157篇 |
国内免费 | 2篇 |
专业分类
林业 | 58篇 |
农学 | 112篇 |
基础科学 | 25篇 |
345篇 | |
综合类 | 413篇 |
农作物 | 122篇 |
水产渔业 | 161篇 |
畜牧兽医 | 1780篇 |
园艺 | 58篇 |
植物保护 | 228篇 |
出版年
2021年 | 30篇 |
2020年 | 40篇 |
2019年 | 38篇 |
2018年 | 45篇 |
2017年 | 50篇 |
2016年 | 48篇 |
2015年 | 39篇 |
2014年 | 46篇 |
2013年 | 162篇 |
2012年 | 103篇 |
2011年 | 100篇 |
2010年 | 60篇 |
2009年 | 64篇 |
2008年 | 121篇 |
2007年 | 109篇 |
2006年 | 106篇 |
2005年 | 107篇 |
2004年 | 82篇 |
2003年 | 96篇 |
2002年 | 112篇 |
2001年 | 112篇 |
2000年 | 98篇 |
1999年 | 64篇 |
1998年 | 39篇 |
1997年 | 37篇 |
1996年 | 41篇 |
1995年 | 43篇 |
1994年 | 28篇 |
1992年 | 42篇 |
1991年 | 65篇 |
1990年 | 64篇 |
1989年 | 53篇 |
1988年 | 54篇 |
1987年 | 59篇 |
1986年 | 61篇 |
1985年 | 57篇 |
1984年 | 52篇 |
1983年 | 50篇 |
1982年 | 36篇 |
1981年 | 30篇 |
1979年 | 31篇 |
1978年 | 33篇 |
1977年 | 37篇 |
1976年 | 31篇 |
1975年 | 29篇 |
1974年 | 36篇 |
1973年 | 35篇 |
1972年 | 35篇 |
1971年 | 33篇 |
1970年 | 34篇 |
排序方式: 共有3302条查询结果,搜索用时 62 毫秒
961.
962.
963.
Laredo FG Belda E Murciano J Escobar M Navarro A Robinson KJ Jones RS 《The Veterinary record》2004,155(21):667-671
Thirty-two dogs undergoing operations to repair a torn cranial cruciate ligament or a fractured long bone were randomly allocated to one of two treatment groups in a study on postoperative pain. Sixteen of the dogs were given 4 mg/kg carprofen and the other 16 were given 0.2 mg/kg meloxicam subcutaneously before the operation. The signs of pain shown by the animals were assessed for 24 hours on a visual analogue scale, a discontinuous scoring system, and a score based on five behavioural and physiological variables. The dogs' heart and respiratory rates and their mean arterial blood pressures were also measured non-invasively at each assessment. Blood samples were taken before the surgery and 24 hours after it, and the concentrations of urea and creatinine were measured in plasma. Both drugs were effective in relieving the signs of pain for up to 24 hours in all the dogs. There were no significant changes in the concentrations of urea and creatinine, and no adverse effects were reported during the postoperative period. 相似文献
964.
: Tetanus with hiatal hernia was diagnosed in a four-month-old female sheepdog pup. The animal was treated with tetanus antitoxin, antibiotics, fluids and intensive nursing care for three weeks and subsequently made a full recovery. 相似文献
965.
: Infection with Angiostrongylus vasorum was diagnosed at necropsy on a dog that died from acute pulmonary haemorrhage, and on recovery of L1 larvae by Baermann examination of faeces from two dogs, one of which had abdominal pain and retroperitoneal haemorrhage, while the other had right-sided heart failure due to cor pulmonale. The presenting signs included syncope (one dog), exercise intolerance (two dogs), cough (two dogs), abdominal pain (one dog) and depression (one dog). One-stage prothrombin time and activated partial thromboplastin time were prolonged in two dogs, buccal mucosal bleeding time was prolonged in one dog and globulin was elevated in all three dogs. Two dogs were treated with fenbendazole and recovered. 相似文献
966.
Although muscle diseases occur relatively rarely in cats, a number of congenital feline myopathies have been described over the last 20 years and are reviewed in this paper. Some of them have been reported exclusively in specific breeds, including the hypokalaemic myopathy of Burmese cats, type IV glycogen storage disease in Norwegian Forest cats, or the myopathy of Devon Rex. Other congenital disorders of muscle and neuromuscular junction such as myotonia congenita, dystrophin-deficient hypertrophic feline muscular dystrophy, laminin alpha2 deficiency, or congenital myasthenia gravis may occur in any cat. A systematic approach is essential in order to efficiently obtain a timely diagnosis in cats showing signs of muscle disease. After a thorough clinical examination, this approach includes blood analyses (eg, serum concentration of muscle enzymes), electrophysiology where available (electromyography, nerve conduction studies), and sampling of muscle biopsies for histological, histochemical and immunohistochemical evaluation. When available, detection of healthy carriers of these genetic disorders is important to eliminate the gene mutations from breeding families. Clinicians regularly receiving feline patients must have a good knowledge of congenital feline myopathies and the features which enable a diagnosis to be made and prognosis given. Besides preserving or restoring the well-being of the myopathic patient, rapid and efficient information and counselling of the breeders are of central importance in order to prevent the recurrence of the problem in specific breeding lines. 相似文献
967.
Silicon enhances the accumulation of diterpenoid phytoalexins in rice: a potential mechanism for blast resistance 总被引:2,自引:0,他引:2
Rodrigues FA McNally DJ Datnoff LE Jones JB Labbé C Benhamou N Menzies JG Bélanger RR 《Phytopathology》2004,94(2):177-183
ABSTRACT Although several reports underscore the importance of silicon (Si) in controlling Magnaporthe grisea on rice, no study has associated this beneficial effect with specific mechanisms of host defense responses against this fungal attack. In this study, however, we provide evidence that higher levels of momilactone phytoalexins were found in leaf extracts from plants inoculated with M. grisea and amended with silicon (Si(+)) than in leaf extracts from inoculated plants not amended with silicon (Si(-) ) or noninoculated Si(+) and Si(-) plants. On this basis, the more efficient stimulation of the terpenoid pathway in Si(+) plants and, consequently, the increase in the levels of momilactones appears to be a factor contributing to enhanced rice resistance to blast. This may explain the lower level of blast severity observed on leaves of Si(+) plants at 96 h after inoculation with M. grisea. The results of this study strongly suggest that Si plays an active role in the resistance of rice to blast rather than the formation of a physical barrier to penetration by M. grisea. 相似文献
968.
Hill RC Bloomberg MS Legrand-Defretin V Burger IH Hillock SM Sundstrom DA Jones GL 《American journal of veterinary research》2000,61(12):1566-1573
OBJECTIVES: To determine maintenance energy requirements and effect of diet on performance of racing Greyhounds. ANIMALS: 7 adult racing Greyhounds. PROCEDURE: Dogs were fed a higher fat and protein (HFP) or a lower fat and protein (LFP) diet for 8 weeks in a crossover design. Dogs were exercised for 15 minutes twice daily in a paddock and raced 500 m twice weekly. Blood gas, hematologic, and serum biochemical analyses were performed before and after racing, and race times were compared at the end of each diet period. RESULTS: Mean race time was significantly shorter (32.81+/-0.65 seconds vs. 33.05+/-0.71 seconds), and mean racing speed over 500 m was significantly faster (15.25+/-0.30 vs. 15.13+/-0.30 m x s(-1)) when dogs were fed the HFP diet than when they were fed the LFP diet. Diet had little or no effect on results of blood gas, hematologic, and serum biochemical analyses, except that Hct was 4% greater before and after racing when the HFP diet was fed than when the LFP diet was fed. Mean SD metabolizable energy intake from weeks 1 through 16 was 155+/-9 kcal x kg(-0.75) x d(-1). CONCLUSIONS AND CLINICAL RELEVANCE: Racing Greyhounds ran faster when fed a diet containing higher fat and protein and lower carbohydrate contents. Their maintenance metabolizable energy requirement was slightly higher than that of moderately active dogs. 相似文献
969.
Plasma and urinary trypsinogen activation peptide in healthy dogs, dogs with pancreatitis and dogs with other systemic diseases 总被引:1,自引:0,他引:1
OBJECTIVE: To determine the specificity and sensitivity of plasma and urinary trypsinogen activation peptide (TAP) concentrations in diagnosing pancreatitis in dogs. DESIGN: Retrospective analysis of clinical cases. PROCEDURE: Dogs were classified into three groups: healthy animals, dogs with confirmed pancreatitis and dogs with nonpancreatic disease, which clinically or biochemically resembled pancreatitis. This last group was further subdivided into dogs with renal and those with nonrenal disease. The plasma and urinary TAP concentration was determined by a competitive enzyme immunoassay. Clinical cases additionally had serum trypsin-like immunoreactivity concentration measured, as well as radiography and ultrasound of the abdomen and further diagnostic procedures. Nonparametric analysis of variance (Kruskal-Wallis test) was performed using Statistix 4.0 program. RESULTS: There was a wide range of urinary TAP concentration in healthy dogs (mean 52.30 nmol/L, standard deviation 55.25) that made interpretation of urinary TAP concentrations difficult in the other groups. There was a narrow reference range for plasma TAP (mean 2.67 nmol/L, standard deviation 0.93). Plasma and urinary TAP concentrations, as well as urinary TAP to creatinine ratio, were all increased in dogs that died with necrotising pancreatitis. Values were not increased in mild, interstitial pancreatitis. Increased plasma TAP concentrations were also present in dogs with severe renal disease. CONCLUSION: Plasma TAP concentration is a good prognostic indicator in naturally occurring pancreatitis in dogs. The failure of TAP to increase in mild pancreatitis, and the increase present in severe renal disease, suggests its measurement has limited application as a sole diagnostic tool for canine pancreatitis. Further investigations are required in order to explain the large variability of urinary TAP concentration and the presence of circulating TAP in healthy dogs. 相似文献
970.
Physical, chemical and biological hazards in veterinary practice 总被引:1,自引:0,他引:1
OBJECTIVE: To identify major occupational hazards encountered by veterinarians and their staff in practice in Australia. PROCEDURE: A literature search of Medical (MEDLINE), Occupational Health and Safety (OSHRAM) and Nursing and Allied Health (CINAHL) electronic data bases plus continual monitoring utilising the Uncover alerting system using the key words, 'occupational injury', 'occupational disease' and 'safety' linked with use of the word 'veterinarians' has found relevant articles. Personal communication with people who have undertaken studies on occupational safety in veterinarians elicited further information. CONCLUSION AND RECOMMENDATIONS: Veterinarians often sustain animal-related injuries, the most common of which are dog and cat bites, cat scratches and being hit or crushed by large animals. The most costly to treat include strains and back injuries. Most veterinarians treat themselves. There is no single reporting system for injuries or disease in veterinarians and reported cases may greatly underestimate the total. There is a need to assess accurately the occupational hazards in veterinary practice, to determine the actual occurrence of injuries and to develop strategies to prevent them. 相似文献