全文获取类型
收费全文 | 1183篇 |
免费 | 125篇 |
国内免费 | 2篇 |
专业分类
林业 | 21篇 |
农学 | 24篇 |
基础科学 | 14篇 |
105篇 | |
综合类 | 202篇 |
农作物 | 75篇 |
水产渔业 | 31篇 |
畜牧兽医 | 715篇 |
园艺 | 8篇 |
植物保护 | 115篇 |
出版年
2020年 | 14篇 |
2019年 | 13篇 |
2018年 | 35篇 |
2017年 | 37篇 |
2016年 | 34篇 |
2015年 | 25篇 |
2014年 | 43篇 |
2013年 | 62篇 |
2012年 | 36篇 |
2011年 | 37篇 |
2010年 | 26篇 |
2009年 | 34篇 |
2008年 | 26篇 |
2007年 | 30篇 |
2006年 | 34篇 |
2005年 | 17篇 |
2004年 | 27篇 |
2003年 | 29篇 |
2002年 | 22篇 |
2001年 | 23篇 |
2000年 | 23篇 |
1999年 | 18篇 |
1998年 | 17篇 |
1997年 | 19篇 |
1995年 | 25篇 |
1993年 | 19篇 |
1992年 | 23篇 |
1991年 | 22篇 |
1990年 | 33篇 |
1989年 | 22篇 |
1988年 | 23篇 |
1987年 | 19篇 |
1986年 | 32篇 |
1985年 | 19篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1982年 | 18篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 17篇 |
1975年 | 10篇 |
1974年 | 20篇 |
1973年 | 21篇 |
1972年 | 18篇 |
1971年 | 15篇 |
1970年 | 17篇 |
1969年 | 10篇 |
1967年 | 12篇 |
1966年 | 13篇 |
排序方式: 共有1310条查询结果,搜索用时 15 毫秒
31.
32.
Mellanby RJ Crisp J De Palma G Spratt DP Urwin D Wright MJ Zago S 《The Journal of small animal practice》2007,48(1):26-31
OBJECTIVES: The aim of this study was to explore the attitudes of veterinarians and clients towards expressions of clinical uncertainty. METHODS: Questionnaires that assessed the respondent's attitudes towards expressions of clinical uncertainty were completed by clients at six small animal practices. In addition, questionnaires that evaluated what veterinarians thought their client's attitudes would be towards expressions of clinical uncertainty were completed by veterinarians. The responses from clients and veterinarians were statistically compared. RESULTS: Veterinarians significantly underestimated the desire of clients to be told about uncertainties in treatment and significantly overestimated how the expression of uncertainty would generally reduce client confidence. Veterinarians significantly overestimated the loss of client confidence resulting from saying "I am not sure about this" and from asking a nurse for advice. Both clients and veterinarians considered that verbal expressions of uncertainty would lead to a greater reduction in client confidence than behavioural expressions of uncertainty. CLINICAL SIGNIFICANCE: This study suggests that most clients want to be told about their veterinarian's clinical uncertainties, and how this uncertainty is expressed can markedly influence client confidence. 相似文献
33.
Welles EG Whatley EM Hall AS Wright JC 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2006,35(1):31-36
BACKGROUND: Urine protein: urine creatinine (UP:UC) ratio determined from the quantitative measurement of protein and creatinine in a single urine sample is the best feasible assessment of clinically significant proteinuria in dogs and cats. A dipstick that measures urine protein, urine creatinine, and UP:UC ratio has been used in human medicine and could have application for veterinary practice. OBJECTIVE: The objective of this study was to compare the Multistix PRO dipstick (Bayer Corporation, Elkhart, IN, USA) to other biochemical methods for determination of urine protein and creatinine, and UP:UC ratio in canine and feline urine. METHODS: A complete urinalysis, including sulfosalicylic acid (SSA) precipitation, was performed on urine samples submitted to our laboratory between February and April 2003 from 100 dogs and 49 cats. Urine protein and creatinine concentrations were determined by the Multistix PRO dipstick using a Clinitek 50 analyzer (Bayer) and compared with the results of SSA precipitation and quantitative biochemical analysis. The UP:UC ratios from the dipstick results (calculated by the Clinitek 50 and also manually) were compared with those calculated from quantitative values. Pearson product-moment correlation analysis and diagnostic sensitivity and specificity (using quantitative results as the gold standard) were determined. RESULTS: For both canine and feline urine, protein and creatinine concentrations determined by the Multistix PRO correlated closely with quantitative concentrations for protein (dogs r = .78, P = .0001; cats r = .87, P = .0001) and creatinine (dogs r = .78, P = .0001; cats r = .76, P = .0001). The Multistix PRO was more sensitive and less specific than SSA precipitation for diagnosing clinically significant proteinuria. UP:UC ratios obtained by manual calculation of dipstick results correlated best with quantitative UP:UC ratios in dogs, and had higher specificity but lower sensitivity for the diagnosis of proteinuria. In cats, UP:UC ratios determined by the dipstick method did not correlate (r = -.24, P = .0974) with quantitative values. CONCLUSIONS: The Multistix PRO, with manual calculation of UP:UC, may be a good alternative for the diagnosis of clinically significant proteinuria in dogs, but not cats. Dipstick creatinine concentration should be considered as an estimate. 相似文献
34.
Jane C.F. Chang Paul Ciaccio Patricia Schroeder Lindsay Wright Russell Westwood Anna-Lena Berg 《Journal of toxicologic pathology》2014,27(1):31-42
AZD3783, a cationic amphiphilic drug and a potent inhibitor of the 5-hydroxytryptamine
(5-HT1B) receptor, was explored as a potential treatment for depression. To
support clinical trials, repeat dose toxicity studies in rats and dogs were conducted.
Here we report toxicity findings in dogs after dosing from 1 to 3 months. In the 1-month
study, there were minimal neuronal vacuolation in the brain, a marked increase in liver
enzymes accompanied by hepatocellular degeneration/necrosis and phospholipidosis (PLD),
and PLD/cholecystitis in the gallbladder of animals dosed at 47 mg/kg/day. In the 3-month
study, neurotoxicity resulted in euthanasia of one animal dosed at 30 mg/kg/day after 86
days. Extensive pathologic changes were seen in all animals in retina epithelium
(inclusion bodies), brain (neuronal vacuolation, degeneration, or necrosis and nerve fiber
degeneration), spinal ganglia (vacuolation, degeneration, or necrosis), as well as sciatic
and optic nerves (degeneration). Pigment-laden macrophages were observed in the lung,
kidney, liver, gallbladder, bone marrow, gastrointestinal tract, and lymphoid tissues.
Also seen were vitrel and retinal hemorrhage in the eyes. A brain concentration and
pathology study showed that the concentration of AZD3783 in the brain was approximately 4
times higher than in the plasma after 4 weeks of dosing, however, they were similar in all
regions examined, and did not correlate with areas with pathologic findings. Our findings
with AZD3783 in dogs have not been reported previously with other CNS compounds that
effect through serotonergic pharmacology. 相似文献
35.
36.
37.
38.
I Esteban-Redondo S W Maley K Thomson S Nicoll S Wright D Buxton E A Innes 《Veterinary parasitology》1999,86(3):155-171
It has been reported in the literature that cattle are more resistant to toxoplasmosis than sheep. Congenital disease due to T. gondii infection is rarely reported in cattle whereas the parasite is a major cause of abortion and neonatal mortality in sheep. It is believed that sheep remain chronically infected for life. Undercooked meat from infected sheep is an important source of infection for man. In contrast cattle are thought to harbour fewer parasite tissue cysts which may not persist for the lifetime of the host. Therefore, cattle are believed to pose less of a risk for human infection. In this study we examined the presence of T. gondii within a range of tissues in sheep and cattle at 6 weeks and 6 months following oral infection with 10(3) or 10(5) sporulated oocysts of T. gondii. The presence of parasite was determined by bioassay in mice and using polymerase chain reaction (PCR). The results from this study show that T. gondii was more frequently and consistently detected in sheep, in particular within brain and heart tissues, whereas parasites were not detected in the samples of tissues taken from cattle. T. gondii was more frequently detected in sheep given the higher dose of T. gondii. Examination of tissues at either 6 weeks or 6 months after infection did not appear to affect the distribution of T. gondii. The polymerase chain reaction has more specificity and sensitivity when detecting the presence of T. gondii in large animals than histological detection. 相似文献
39.
40.
Cooper-Prado MJ Long NM Wright EC Goad CL Wettemann RP 《Journal of animal science》2011,89(4):1020-1027
Spring-calving Angus cows (n = 30) were used to evaluate changes in ruminal temperature (RuT) related to parturition and estrus. Cows were synchronized and artificially inseminated with semen from a single sire. Temperature boluses were placed in the rumen at 7.0 ± 0.2 mo of gestation. Boluses were programmed to transmit RuT every 15 min. Cows (BW = 623 ± 44 kg, BCS = 4.9 ± 0.4) calved during 3 wk, and estrus was synchronized at 77 ± 7 d after calving with PGF(2α). Cows were observed every 12 h to detect estrus. Daily average ambient temperatures ranged from 2 to 22 °C during parturition (February to March) and 17 to 25 °C during estrus (May to June). Ruminal temperature from 7 d before to 3 d after parturition and 2 d before to 2 d after visual detection of estrus was analyzed using the MIXED procedure. Ruminal temperatures <37.72 °C were attributed to water consumption and excluded from analyses. Day did not influence (P = 0.36) RuT from d -2 to -7 before parturition (38.94 ± 0.05 °C). Ruminal temperature decreased (P < 0.001) from d -2 to d -1 before parturition (38.88 ± 0.05 to 38.55 ± 0.05 °C, respectively). Ruminal temperature was not influenced (P = 0.23) by day from 1 d before to 3 d after parturition (38.49 ± 0.05 °C). Ruminal temperature at 0 to 8 h after detection of estrus (38.98 ± 0.09 °C) was greater (P < 0.001) compared with RuT at the same daily hour of the day before (38.37 ± 0.11 °C) or the day after estrus (38.30 ± 0.09 °C). Ambient temperature did not influence (P > 0.30) RuT at parturition or estrus. Ruminal temperature decreased the day before parturition and increased at estrus in spring-calving beef cows and has potential use as a predictor of parturition and estrus. 相似文献