全文获取类型
收费全文 | 231865篇 |
免费 | 12515篇 |
国内免费 | 174篇 |
专业分类
林业 | 9327篇 |
农学 | 7292篇 |
基础科学 | 1544篇 |
28672篇 | |
综合类 | 40755篇 |
农作物 | 8999篇 |
水产渔业 | 11580篇 |
畜牧兽医 | 117103篇 |
园艺 | 3089篇 |
植物保护 | 16193篇 |
出版年
2018年 | 3136篇 |
2017年 | 3547篇 |
2016年 | 3249篇 |
2015年 | 2751篇 |
2014年 | 3484篇 |
2013年 | 8915篇 |
2012年 | 6432篇 |
2011年 | 8001篇 |
2010年 | 5139篇 |
2009年 | 5257篇 |
2008年 | 7831篇 |
2007年 | 7467篇 |
2006年 | 7060篇 |
2005年 | 6546篇 |
2004年 | 6325篇 |
2003年 | 6440篇 |
2002年 | 6040篇 |
2001年 | 7118篇 |
2000年 | 6962篇 |
1999年 | 5594篇 |
1998年 | 2402篇 |
1997年 | 2377篇 |
1996年 | 2219篇 |
1995年 | 2703篇 |
1994年 | 2418篇 |
1993年 | 2306篇 |
1992年 | 4667篇 |
1991年 | 4882篇 |
1990年 | 4835篇 |
1989年 | 4837篇 |
1988年 | 4443篇 |
1987年 | 4526篇 |
1986年 | 4665篇 |
1985年 | 4510篇 |
1984年 | 3725篇 |
1983年 | 3364篇 |
1982年 | 2334篇 |
1981年 | 2154篇 |
1979年 | 3458篇 |
1978年 | 2875篇 |
1977年 | 2421篇 |
1976年 | 2327篇 |
1975年 | 2471篇 |
1974年 | 3057篇 |
1973年 | 3107篇 |
1972年 | 2975篇 |
1971年 | 2695篇 |
1970年 | 2546篇 |
1969年 | 2508篇 |
1967年 | 2159篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
911.
912.
全球禽肉生产和贸易中的沙门菌风险评估与控制 总被引:1,自引:0,他引:1
G.Mead A.M.Lammerding N.Cox M.P.Doyle F.Humbert A.Kulikocskiy A.Panin V.P.do Nascimento M.Wierup 《中国家禽》2011,33(5)
1 禽源沙门菌对公共卫生的影响
在许多国家,沙门菌仍是引发食源性肠道疾病的主要原因.沙门菌通常存在于家畜、家禽中,也可在啮齿类、爬行类和鸟类等野生动物中发现.当农场的禽群感染沙门菌后,通常会有一部分家禽的消化道中携带沙门菌,但并无症状.随后,沙门菌可能会通过粪便污染感染动物屠体. 相似文献
913.
A three-year-old, male, entire, Yorkshire terrier was presented with peracute onset of abdominal pain and vomitus. Clinicopathological abnormalities included severely increased serum lipase activity, immeasurably high serum trypsin-like immunoreactivity and mild hypocalcaemia. Canine pancreatic lipase immunoreactivity (cPLI) was intended to be measured, however, the sample got lost. Ultrasonography revealed a hypoechoic pancreas with small amounts of peripancreatic fluid and hyperechogenic mesentery. Acute pancreatitis (AP) was diagnosed and the dog recovered with appropriate therapy within 48 hours. Clomipramine, a selective serotonin reuptake inhibitor (SSRI) for alleviating signs of separation anxiety had been given for seven weeks. Two similar, albeit less severe, episodes associated with previous courses of clomipramine had occurred eight months earlier that responded to discontinuing clomipramine and supportive care. As SSRIs are associated with AP in human beings and no other trigger could be identified, we conclude that clomipramine should be considered as a potential cause when investigating causes for AP in susceptible breeds or other dogs presenting with compatible clinical signs. 相似文献
914.
J. IGNACIO ARIAS DVM CRISTIAN TORRES DVM DANIEL SAEZ DVM 《Veterinary surgery : VS》2009,38(4):463-466
Objective— To report arthroscopic diagnosis and treatment of synovial hemangioma in a dog.
Study Design— Case report.
Animal— Standard Poodle (8-year-old neutered male).
Methods— A soft tissue density mass observed radiographically in the left stifle joint of a dog with a 2-month history of recurrent lameness, hemarthrosis, and a slight cranial drawer sign, was located by diagnostic arthroscopy and surgically excised via arthrotomy.
Results— Histologic evaluation revealed tissue composed of variably sized cavernous vascular spaces filled with erythrocytes that were considered compatible with synovial hemangioma.
Conclusions— In this dog, synovial hemangioma evident as a soft tissue mass on radiographs was associated with chronic lameness and hemarthrosis, and resolved with surgical excision.
Clinical Relevance— Synovial hemangioma, although seemingly rare in dogs, should be considered in the differential diagnosis for nontraumatic, recurrent lameness, and unresponsive to anti-inflammatory therapy when there is a circumscribed intracapsular soft tissue mass evident radiographically together with hemarthrosis. 相似文献
Study Design— Case report.
Animal— Standard Poodle (8-year-old neutered male).
Methods— A soft tissue density mass observed radiographically in the left stifle joint of a dog with a 2-month history of recurrent lameness, hemarthrosis, and a slight cranial drawer sign, was located by diagnostic arthroscopy and surgically excised via arthrotomy.
Results— Histologic evaluation revealed tissue composed of variably sized cavernous vascular spaces filled with erythrocytes that were considered compatible with synovial hemangioma.
Conclusions— In this dog, synovial hemangioma evident as a soft tissue mass on radiographs was associated with chronic lameness and hemarthrosis, and resolved with surgical excision.
Clinical Relevance— Synovial hemangioma, although seemingly rare in dogs, should be considered in the differential diagnosis for nontraumatic, recurrent lameness, and unresponsive to anti-inflammatory therapy when there is a circumscribed intracapsular soft tissue mass evident radiographically together with hemarthrosis. 相似文献
915.
Christa Horvath-Ungerboeck Keith L. Thoday Darren J. Shaw Adri H. M. van den Broek 《Veterinary dermatology》2009,20(4):233-242
Thirty dogs with atopic dermatitis were given tepoxalin (Zubrin®, Intervet/Schering-Plough Animal Health, Boxmeer, the Netherlands) or placebo once daily for 4 weeks, followed by a wash-out period of 1 week before reversing the treatments. Pruritus was scored by the owners using the Edinburgh Pruritus Scale and one investigator employed a modification of the Canine Atopic Dermatitis Extent and Severity Index-01 (mCADESI-01) to score the physical lesions. After administration of tepoxalin there was a ≥ 50% reduction in pruritus and mCADESI-01 scores in 36% and 25% of the dogs, respectively, whereas following administration of the placebo there was a ≥ 50% reduction in pruritus and mCADESI-01 scores in only 25% and 16% of the dogs, respectively. Analysis of pooled data indicated that tepoxalin resulted in a significant reduction in pruritus ( P = 0.012) and mCADESI-01 ( P = 0.002) scores but there was no significant change after placebo. The median pruritus scores before and after tepoxalin were 2 (range 1–5) and 1 (range 0–5), respectively, and before and after placebo were 2 (range 0–4) and 2 (range 0–4), respectively. The median mCADESI scores before and after tepoxalin were 23 (range 0–68) and 16 (range 0–72), respectively, and before and after placebo were 18 (range 3–79) and 24 (range 0–65), respectively. At the dose used in this study (10.0–19.1 mg kg−1 ), tepoxalin was well-tolerated and no adverse effects were noted. 相似文献
916.
917.
MARCY J. SOUZA JONATHAN S. WALL ALAN STUCKEY GREGORY B. DANIEL 《Veterinary radiology & ultrasound》2011,52(3):340-344
Positron emission tomography (PET) is often used to stage and monitor human cancer and has recently been used in a similar fashion in veterinary medicine. The most commonly used radiopharmaceutical is 2‐Deoxy‐2‐[18F]‐Fluoro‐d ‐glucose (18F‐FDG), which is concentrated and trapped within cells that use glucose as their energy substrate. We characterized the normal distribution of 18F‐FDG in 10 healthy Hispaniolan Amazon parrots (Amazona ventralis) by performing whole body PET scans at steady state, 60 min after injection. Significant variability was found in the intestinal activity. Avian species are known to reflux fluid and electrolytes from their cloaca into their colon. To evaluate reflux as the cause of variability in intestinal distribution of 18F‐FDG, dynamic PET scans were performed on the coelomic cavity of six Hispaniolan Amazon parrots from time 0 to 60 min postinjection of radiotracer. Reflux of radioactive material from the cloaca into the colon occurred in all birds to varying degrees and occurred before 60 min. To evaluate the intestinal tract of clinical avian patients, dynamic scans must be performed starting immediately after injection so that increased radioactivity due to metabolism or hypermetabolic lesions such as cancer can be differentiated from increased radioactivity due to reflux of fluid from the cloaca. 相似文献
918.
J. Kidd 《Equine Veterinary Education》2011,23(6):314-323
Fractures of the pedal bone are usually the result of direct trauma, and are relatively commonly encountered in equine practice. Either front or hind feet may be affected. Seven distinct fracture types are recognised. Type I fractures involve the palmar/plantar process and do not enter the distal interphalangeal (DIP) joint. Type II fractures are oblique or parasagittal fractures that are articular but are not on the midline. Type III fractures are midline articular fractures that bisect the pedal bone into 2 equal halves. Type IV fractures involve the extensor (pyramidal) process of the pedal bone. Type V fractures are comminuted and split the pedal bone into multiple fragments. Type VI fractures are solar margin fractures. Type VII fractures are exclusive to foals and are also fractures of the solar margin. In most cases the onset of clinical signs is acute. The diagnosis is usually achieved by radiography, although computed tomography or magnetic resonance imaging can be helpful in some cases. Treatment options include surgical and nonsurgical therapies. The prognosis for articular fractures (Types II and III) is worse than for nonarticular fractures (Types I, IV, VI and VII) because of the likelihood of osteoarthritis within the DIP joint. Nonarticular fractures carry a good prognosis if a long enough convalescence is undertaken. Comminuted fractures (Type V) carry a poor, but not hopeless, prognosis. 相似文献
919.
920.
Fractures of the accessory carpal bone in 35 racing Greyhounds were classified into five types. Type I fractures (27 fractures) involved the distal articular surface of the accessory carpal bone, type II (6 fractures) were of the proximal articular margin, type III (1 fracture) were at the origin of the accessorometacarpal ligaments, type IV (6 fractures) were avulsion fractures at the tendon of insertion of the flexor carpi ulnaris muscle, and type V (3 fractures) were comminuted fractures. 相似文献