全文获取类型
收费全文 | 1444篇 |
免费 | 121篇 |
专业分类
林业 | 86篇 |
农学 | 32篇 |
基础科学 | 2篇 |
213篇 | |
综合类 | 184篇 |
农作物 | 56篇 |
水产渔业 | 88篇 |
畜牧兽医 | 820篇 |
园艺 | 33篇 |
植物保护 | 51篇 |
出版年
2024年 | 6篇 |
2023年 | 25篇 |
2022年 | 17篇 |
2021年 | 45篇 |
2020年 | 67篇 |
2019年 | 61篇 |
2018年 | 50篇 |
2017年 | 49篇 |
2016年 | 45篇 |
2015年 | 40篇 |
2014年 | 45篇 |
2013年 | 64篇 |
2012年 | 115篇 |
2011年 | 137篇 |
2010年 | 63篇 |
2009年 | 45篇 |
2008年 | 88篇 |
2007年 | 92篇 |
2006年 | 81篇 |
2005年 | 61篇 |
2004年 | 46篇 |
2003年 | 62篇 |
2002年 | 61篇 |
2001年 | 11篇 |
2000年 | 18篇 |
1999年 | 13篇 |
1998年 | 7篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 18篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1978年 | 8篇 |
1976年 | 7篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有1565条查询结果,搜索用时 15 毫秒
81.
Marlis L. Rezende Ryan A. Ferris Britta S. Leise Khursheed R. Mama David A. Scofield Patrick M. McCue 《Journal of Equine Veterinary Science》2014
This case report describes the occurrence of persistent penile erection in a breeding stallion that occurred while the horse was under inhalant anesthesia for a carpal arthroscopy. The horse had no history of breeding problems, and no abnormalities were detected on physical examination, complete blood count, or serum chemistry tests performed prior to surgery. Anesthesia was induced with guaifenesin and ketamine after sedation with xylazine and was maintained with isoflurane in 100% oxygen. Penile erection developed approximately 35 minutes after induction and persisted for over 2 hours despite various physical and pharmacological attempts to alleviate it (massage, cold compresses, intravenous benztropine administration, and intracavernosal phenylephrine). Successful resolution of the erection was obtained by cannulation and drainage of blood from the corpus cavernosum and subsequent irrigation with heparinized sterile saline and infusion of phenylephrine in the corpus cavernosum. The detumescent penis was placed back into the sheath, and purse string sutures were placed in the sheath to ensure the penis would remain inside the sheath during recovery. The stallion's recovery from anesthesia was uneventful, the sutures were removed, and the horse was fitted with a penile sling to prevent additional edema or trauma. The stallion recovered completely from the persistent penile erection. Semen was collected 6 days after the event, and he returned to normal pasture breeding 6 weeks after surgery. 相似文献
82.
83.
Effects of earthworm casts on soil nutrient dynamics and their responses to changing moisture availability in subtropical ecosystems remain poorly understood. This study aimed to examine short-term carbon(C) and nitrogen(N) dynamics and their interactions with wetting-drying cycles in three different structural forms(i.e., granular, globular, and heap-like) of Amynthas earthworm casts. The rates of C and N mineralization in the earthworm casts were examined under two different wetting-drying cycles(i.e., 2-d and 4-d wetting intervals) using a rainfall simulation experiment. After three simulated rainfall events, subsamples of the earthworm casts were further incubated for 4 d for the determination of CO_2 and N_2O fluxes. The results of this study indicated that the impacts of wetting-drying cycles on the short-term C and N dynamics were highly variable among the three cast forms, but wetting-drying cycles significantly reduced the cumulative CO_2 and N_2O fluxes by 62%–83% and 57%–85%, respectively, when compared to the control without being subjected to any rainfall events. The C mineralization rates in different cast forms were affected by the amount of organic substrates and N content in casts, which were associated with the food preference and selection of earthworms. Meanwhile, the cumulative N_2O fluxes did not differ among the three cast forms. Repeated wetting and drying of casts not only enhanced aggregate stability by promoting bonds between the cast particles, but also inhibited microbial survival and growth during the prolonged drying period, which together hindered decomposition and denitrification. Our findings demonstrated that the interactions between the structural forms, aggregate dynamics, and C and N cycling in the earthworm casts were highly complex. 相似文献
84.
Influence of orthopedic reinforced gloves versus double standard gloves on contamination events during small animal orthopedic surgery 下载免费PDF全文
85.
Background
Expression levels for genes of interest must be normalized with an appropriate reference, or housekeeping gene, to make accurate comparisons of quantitative real-time PCR results. The purpose of this study was to identify the most stable housekeeping genes in porcine articular cartilage subjected to a mechanical injury from a panel of 10 candidate genes.Results
Ten candidate housekeeping genes were evaluated in three different treatment groups of mechanically impacted porcine articular cartilage. The genes evaluated were: beta actin, beta-2-microglobulin, glyceraldehyde-3-phosphate dehydrogenase, hydroxymethylbilane synthase, hypoxanthine phosphoribosyl transferase, peptidylprolyl isomerase A (cyclophilin A), ribosomal protein L4, succinate dehydrogenase flavoprotein subunit A, TATA box binding protein, and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein—zeta polypeptide. The stability of the genes was measured using geNorm, BestKeeper, and NormFinder software. The four most stable genes measured via geNorm were (most to least stable) succinate dehydrogenase flavoprotein, subunit A, peptidylprolyl isomerase A, glyceraldehyde-3-phosphate dehydrogenase, beta actin; the four most stable genes measured via BestKeeper were glyceraldehyde-3-phosphate dehydrogenase, peptidylprolyl isomerase A, beta actin, succinate dehydrogenase flavoprotein, subunit A; and the four most stable genes measured via NormFinder were peptidylprolyl isomerase A, succinate dehydrogenase flavoprotein, subunit A, glyceraldehyde-3-phosphate dehydrogenase, beta actin.Conclusions
BestKeeper, geNorm, and NormFinder all generated similar results for the most stable genes in porcine articular cartilage. The use of these appropriate reference genes will facilitate accurate gene expression studies of porcine articular cartilage and suggest appropriate housekeeping genes for articular cartilage studies in other species. 相似文献86.
87.
88.
C. W. Ryan K. Bishop D. D. Blaney S. J. Britton F. Cantone C. Egan M. G. Elrod C. W. Frye A. M. Maxted G. Perkins 《Zoonoses and public health》2018,65(4):420-424
Melioidosis in humans presents variably as fulminant sepsis, pneumonia, skin infection and solid organ abscesses. It is caused by Burkholderia pseudomallei, which in the United States is classified as a select agent, with “potential to pose a severe threat to both human and animal health, to plant health or to animal and plant products” (Federal Select Agent Program, http://www.selectagents.gov/ , accessed 22 September 2016). Burkholderia pseudomallei is found in soil and surface water in the tropics, especially South‐East Asia and northern Australia, where melioidosis is endemic. Human cases are rare in the United States and are usually associated with travel to endemic areas. Burkholderia pseudomallei can also infect animals. We describe a multijurisdictional public health response to a case of subclinical urinary B. pseudomallei infection in a dog that had been adopted into upstate New York from a shelter in Thailand. Investigation disclosed three human contacts with single, low‐risk exposures to the dog's urine at his residence, and 16 human contacts with possible exposure to his urine or culture isolates at a veterinary hospital. Contacts were offered various combinations of symptom/fever monitoring, baseline and repeat B. pseudomallei serologic testing, and antibiotic post‐exposure prophylaxis, depending on the nature of their exposure and their personal medical histories. The dog's owner accepted recommendations from public health authorities and veterinary clinicians for humane euthanasia. A number of animal rescue organizations actively facilitate adoptions into the United States of shelter dogs from South‐East Asia. This may result in importation of B. pseudomallei into almost any community, with implications for human and animal health. 相似文献
89.
Evason MD Taylor SM Bebchuk TN 《The Canadian veterinary journal. La revue veterinaire canadienne》2007,48(3):296-298
A 4.5-month-old, male domestic shorthair was presented with bilateral femoral fractures after falling from a low height. Radiographs revealed reduced radio-opacity and thin cortices of all long bones. A presumptive diagnosis of osteodystrophy, secondary to osteogenesis imperfecta, was made on postmortem examination. 相似文献
90.
Plasma fentanyl concentrations in awake cats and cats undergoing anesthesia and ovariohysterectomy using transdermal administration 总被引:1,自引:0,他引:1
Objective To measure the plasma fentanyl concentrations achieved over time with transdermal fentanyl patches in awake cats and cats undergoing anesthesia and ovariohysterectomy. Study design Randomized prospective experimental study. Animals Twenty‐four purpose‐bred cats. Methods Cats were randomly assigned to three groups for Part I of a larger concurrent study. Group P received only a 25 μg hour?1 transdermal fentanyl patch. Group P/A received the patch and anesthesia. Group A received only anesthesia. After a minimum 1‐week washout period, the cats were randomly reassigned to two groups for Part II of the larger study. Group P/A/O received the patch, anesthesia and ovariohysterectomy. Group A/O received anesthesia and ovariohysterectomy. Patches were left in place for 72 hours and plasma samples were obtained for fentanyl analysis while the patches were in place, and for 8 hours after patch removal for cats in Group P, P/A, and P/A/O. Results The 25 μg hour?1 transdermal fentanyl patches were well tolerated by the cats in this study (mean body weight of 3.0 kg) and no overt adverse effects were noted. Mean plasma fentanyl concentrations over time, mean plasma fentanyl concentrations at specific times (8, 25, 49, and 73 hours after patch placement), time to first detectable plasma fentanyl concentration, time to reach maximum plasma fentanyl concentration, maximum plasma fentanyl concentration, mean plasma fentanyl concentration from 8 to 73 hours, elimination half‐life, and total area under concentration (AUC) were not statistically different among the groups. Conclusions Halothane anesthesia and anesthesia/ovariohysterectomy did not significantly alter the plasma fentanyl concentrations achieved or pharmacokinetic parameters measured, when compared with awake cats. There was a high degree of individual variability observed both within and between groups of cats in parameters measured. Clinical significance The high degree of variability observed suggests that careful observation of cats with fentanyl patches in place is required to assess efficacy and any potential adverse effects. Anesthesia and anesthesia/ovariohysterectomy do not appear to alter plasma fentanyl concentrations achieved by placement of a 25 μg hour?1 transdermal fentanyl patch when compared to cats not undergoing these procedures. 相似文献