全文获取类型
收费全文 | 2527篇 |
免费 | 147篇 |
国内免费 | 9篇 |
专业分类
林业 | 155篇 |
农学 | 60篇 |
基础科学 | 9篇 |
421篇 | |
综合类 | 404篇 |
农作物 | 104篇 |
水产渔业 | 210篇 |
畜牧兽医 | 1022篇 |
园艺 | 58篇 |
植物保护 | 240篇 |
出版年
2023年 | 12篇 |
2022年 | 21篇 |
2021年 | 41篇 |
2020年 | 64篇 |
2019年 | 72篇 |
2018年 | 50篇 |
2017年 | 67篇 |
2016年 | 74篇 |
2015年 | 51篇 |
2014年 | 67篇 |
2013年 | 119篇 |
2012年 | 172篇 |
2011年 | 193篇 |
2010年 | 116篇 |
2009年 | 84篇 |
2008年 | 173篇 |
2007年 | 167篇 |
2006年 | 177篇 |
2005年 | 163篇 |
2004年 | 137篇 |
2003年 | 145篇 |
2002年 | 147篇 |
2001年 | 25篇 |
2000年 | 19篇 |
1999年 | 24篇 |
1998年 | 23篇 |
1997年 | 30篇 |
1996年 | 18篇 |
1995年 | 28篇 |
1994年 | 23篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 17篇 |
1990年 | 13篇 |
1989年 | 18篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有2683条查询结果,搜索用时 0 毫秒
101.
Maximilian Estevan Oliveira Jssica Campanholi Roberta Lima Cavalcante Felipe Silveira Moreno Edson Hideaki Yoshida Murilo Melo Juste Dini lvio Franco de Camargo Aranha Jos Carlos Cogo Lourdes Dias Stephen Hyslop Denise Grotto Valquíria Miwa Hanai‐Yoshida Yoko Oshima‐Franco 《Journal of Veterinary Emergency and Critical Care》2020,30(3):286-294
102.
Mehl ML Kyles AE Reimer SB Flynn AK Pollard RE Nyland T Kass PH Griffey SM Gregory CR 《Veterinary surgery : VS》2006,35(4):341-346
OBJECTIVE: To determine the relative importance of ischemic injury to delayed graft function (DGF) in cats. STUDY DESIGN: Experimental study. ANIMALS: Six intact female cats. METHODS: Cats had renal autograft transplantation without ureteral transection and reimplantation and a contralateral nephrectomy. Serum creatinine and blood urea nitrogen (BUN) concentrations were measured regularly and abdominal ultrasound was performed before surgery, the day after surgery and twice weekly thereafter. Ultrasound-guided renal biopsy was performed on day 7. Cats were euthanatized on day 21. Histology of the autograft, ureter, bladder, vascular anastomoses sites, and contralateral kidney were performed. Observations were compared with those from an historic group of research cats that had extravesicular ureteroneocystostomy and contralateral nephrectomy. RESULTS: Five cats completed the study. Serum creatinine and BUN concentrations increased after surgery, peaking at 3.2+/-0.8 and 77.6+/-15.9 mg/dL, respectively, 1-2 days after surgery. Serum creatinine concentration returned to the reference interval by 6 days after surgery. BUN gradually decreased in all cats but did not return to the reference interval by study end. Serum creatinine and BUN concentrations were consistently lower but not significantly so (P=.29 and .56, respectively) compared with the historic ureteroneocystostomy group. No ultrasonographic abnormalities or renal biopsy histologic abnormalities were observed. At necropsy, 1 autograft had generalized interstitial fibrosis. CONCLUSION: Harvesting the renal graft and the ischemia before revascularization causes impaired renal function after engraftment. CLINICAL RELEVANCE: The process of harvesting and reimplanting the renal graft can contribute to DGF in cats, independent of ureteral obstruction. 相似文献
103.
Hunter SL Culp LB Muir WW Lerche P Birchard SJ Smeak DD McLoughlin MA 《Veterinary surgery : VS》2003,32(4):336-340
OBJECTIVE: To report the use of sodium nitroprusside to induce deliberate hypotension to reduce hemorrhage and facilitate surgical ligation of complicated patent ductus arteriosus (PDA) in dogs. STUDY DESIGN: Retrospective study. ANIMALS: Six dogs. METHODS: Hemorrhage occurred during surgical ligation of PDA in 5 dogs. Surgical dissection and isolation of the PDA were very difficult in a sixth dog that was considered to be at increased risk for ductus rupture. Sodium nitroprusside (5 to 25 microg/kg/min intravenously) was administered to these 6 dogs to induce hypotension to reduce blood loss and facilitate surgical ligation of the PDA. RESULTS: Sodium nitroprusside infusion reduced blood pressure (mean arterial pressure, 45 to 60 mm Hg) within 5 to 10 minutes and hemorrhage from the PDA, facilitating its surgical ligation. Recovery from surgery and anesthesia was uneventful in all 6 dogs. CONCLUSIONS: Sodium nitroprusside infusion can be used to induce deliberate hypotension in dogs to facilitate surgical ligation of PDA. CLINICAL RELEVANCE: Sodium nitroprusside infusion produces hypotension within 5 to 10 minutes and is easy to control, rapidly abates, and should help to facilitate surgical ligation of PDA. 相似文献
104.
Nathalie C. Newby Cassandra B. Tucker David L. Pearl Stephen J. LeBlanc Ken E. Leslie Marina A.G. von Keyserlingk Todd F. Duffield 《The Canadian veterinary journal. La revue veterinaire canadienne》2014,55(5):442-448
Post-operative pain management following rumen surgery is not common practice. We examined the effect of providing the pain medication ketoprofen to dairy cattle following the first stage of a rumen cannulation surgery, which involves an incision in the body wall and exteriorizing and clamping the rumen. The results of this study provide clear evidence that the first stage of the surgery was painful and ketoprofen at the time of and 24 h following surgery, alleviated some, but not all, of the post-surgical pain. Pain mitigation should be included when performing flank surgery in cattle. 相似文献
105.
Garcia-Pereira FL Greene SA Keegan RD McEwen MM Tibary A 《Veterinary anaesthesia and analgesia》2007,34(4):269-274
OBJECTIVE: To determine the effects of intravenous (IV) butorphanol on the cardiopulmonary system and on the bispectral index (BIS) in isoflurane-anesthetized alpacas. STUDY DESIGN: Randomized, blinded cross-over experimental trial. ANIMALS: Eight healthy, young (3 +/- 1 SD years) adult female alpacas weighing 64 +/- 9 SD kg. METHODS: Alpacas were anesthetized with isoflurane by mask followed by tracheal intubation and maintenance of anesthesia with isoflurane in oxygen and intermittent positive pressure ventilation. Animals were assigned to two treatments, butorphanol (0.1 mg kg(-1), IV) and saline (0.01 mL kg(-1), IV) in a randomized manner allowing a 2-week interval between treatments. Cardiovascular variables included systolic, diastolic, and mean arterial blood pressure, heart rate, pulmonary arterial pressure, pulmonary arterial occlusion pressure (PAOP), central venous pressure, cardiac output, and pulmonary temperature (TEMP). Cardiac index, systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR) were calculated. Bispectral index was also measured. Arterial and mixed venous blood samples were collected for blood gas analysis. All variables were recorded at baseline (time 0) and at 5, 10, 15, 30, 45 and 60 minutes following injection and were analyzed by using repeated-measures ANOVA (p < 0.05). PAOP, PVR, and BIS were analyzed by paired t-tests. RESULTS: Butorphanol decreased SVR at all times when compared with the baseline, but no difference was detected between treatments. TEMP decreased with time in both treatments, but they were not different from each other. Other cardiovascular, BIS, and blood gas variables were not different between groups. CONCLUSION AND CLINICAL RELEVANCE: We conclude that butorphanol had minimal effects on the cardiovascular system of the alpacas, causing a mild decrease in SVR. 相似文献
106.
107.
Zur G Ihrke PJ White SD Kass PH 《Veterinary therapeutics : research in applied veterinary medicine》2002,3(1):88-96
Antihistamines were prescribed for 178 of 271 dogs with a diagnosis of atopic dermatitis at the Veterinary Medical Teaching Hospital of the University of California, Davis from 1992 to 1998. Fifty-four percent of 166 dogs given antihistamines responded favorably to these treatments, with 27% of the responses rated as good and 27% rated as moderate. Diphenhydramine and hydroxyzine were the most commonly used antihistamines and were the most frequently effective. Chlorpheniramine and clemastine were administered less frequently and had much lower positive response rates. Responses to antihistamines as a group were significantly better in dogs having onset of clinical signs at younger ages (odds ratios for 1-year increase in age = 0.72, 95% confidence interval = 0.57 to 0.91, P =.005). 相似文献
108.
109.
110.