全文获取类型
收费全文 | 1787篇 |
免费 | 107篇 |
国内免费 | 2篇 |
专业分类
林业 | 229篇 |
农学 | 116篇 |
基础科学 | 19篇 |
377篇 | |
综合类 | 108篇 |
农作物 | 134篇 |
水产渔业 | 162篇 |
畜牧兽医 | 568篇 |
园艺 | 23篇 |
植物保护 | 160篇 |
出版年
2023年 | 14篇 |
2022年 | 29篇 |
2021年 | 53篇 |
2020年 | 73篇 |
2019年 | 66篇 |
2018年 | 77篇 |
2017年 | 77篇 |
2016年 | 74篇 |
2015年 | 50篇 |
2014年 | 76篇 |
2013年 | 158篇 |
2012年 | 111篇 |
2011年 | 106篇 |
2010年 | 82篇 |
2009年 | 66篇 |
2008年 | 83篇 |
2007年 | 58篇 |
2006年 | 71篇 |
2005年 | 47篇 |
2004年 | 40篇 |
2003年 | 43篇 |
2002年 | 47篇 |
2001年 | 50篇 |
2000年 | 35篇 |
1999年 | 27篇 |
1998年 | 11篇 |
1997年 | 25篇 |
1996年 | 15篇 |
1995年 | 7篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 8篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 8篇 |
1983年 | 9篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1973年 | 9篇 |
1971年 | 6篇 |
1970年 | 6篇 |
1969年 | 8篇 |
1968年 | 9篇 |
排序方式: 共有1896条查询结果,搜索用时 140 毫秒
31.
32.
A Q Khan 《The British veterinary journal》1968,124(4):171-173
33.
M.A. Khan 《Veterinary parasitology》1981,8(4):327-336
In two experiments, a pour-on application of phosmet at 25 mg kg?1 reduced the harassment of cattle by black flies for up to 5–6 weeks posttreatment. During this period, the treated groups either gained more weight or loss less weight than their controls. The untreated groups made compensatory gains when teh black fly activity decreased or ceased. No significant differences existed between the average daily gains of a treated group and its control either for the posttreatment-periods of 9 and 15 weeks or for the experimental periods of 15 and 20 weeks in the two experiments.Black fly toxemia was not seen in indigenous cattle or in naive steers brought into a black fly infested area 1–2 weeks before the onset of black fly activity. 相似文献
34.
35.
Draghia-Akli R Cummings KK Khan AS Brown PA Carpenter RH 《Journal of animal science》2003,81(9):2301-2310
Our study focused on the evaluation of the pharmacological and toxicological effects of plasmid-mediated GHRH supplementation with electroporation in normal adult dogs over a 180-d period. Twenty-eight dogs (< 2 yr of age) were randomized to four groups. Three groups (four dogs/sex for each group) were treated with ascending doses of GHRH-expressing plasmid: 0.2, 0.6, and 1 mg. One group (two dogs of each sex) served as the control. Clinical observations and body weights were recorded. Hematological, serum biochemical, and urine analyses were performed. Serum IGF-I, ACTH, and insulin were determined. Necropsies were performed on d 93 and 180; organs were weighed and tissues were fixed and processed for light microscopy. Selected tissues were used to assess plasmid biodistribution on d 93. At all doses, plasmid GHRH caused increased weight gain (P < 0.001), without organomegaly. Serum glucose and insulin in fasted dogs remained within normal ranges at all time points. Adrenocorticotropic hormone was normal in all groups. Significant increases in number of red blood cells, hematocrit, and hemoglobin (P < 0.01) were observed. In conclusion, our study shows that plasmid-mediated GHRH supplementation is safe in electroporated doses up to 1.0 mg in young healthy dogs. 相似文献
36.
The spike 1 (S1) surface glycoprotein of infectious bronchitis virus (IBV) is the major inducer of the generation of virus neutralizing antibodies, and the administration of purified S1 has been shown to elicit a protective immune response against virulent virus challenge. On the basis of these observations, recombinant fowl poxvirus (rFPV) containing a cDNA copy of the S1 gene of IBV Mass 41 (rFPV-S1) was constructed and its immunogenicity and vaccine potential were evaluated. Initially, rFPV-S1 was shown to express the S1 in vito by indirect immunofluorescence staining and western blot analyses. Later, in vivo expression was demonstrated by the detection of IBV-specific serum immunoglobulin G and neutralization antibodies in the sera of chickens immunized with rFPV-S1. That the recombinant virus elicited anti-IBV protective immunity was indicated by the manifested, relatively mild clinical signs of disease, decreased titers of recovered challenge virus, and less severe histologic changes of the tracheas in virulent IBV Mass 41-challenged chickens previously receiving rFPV-S1 as compared with parental fowl poxvirus (FPV)-vaccinated control birds. In contrast, chickens immunized with either recombinant or parental FPV were resistant to a subsequent virulent FPV challenge. As to a preferred method of immunization, wing web administration appeared to be superior to the subcutaneous route because a greater percentage of birds vaccinated by the former protocol exhibited an anti-IBV humoral immune response. Thus, rFPV-S1 has potential as a poultry vaccine against both fowl pox and infectious bronchitis. 相似文献
37.
A flock of 810 pheasants experienced 6.2% mortality over 6 days. Affected birds were weak and lethargic for up to 24 hr before death. Examined birds were thin, and gross lesions consisted of thick opaque crops and cecal cores. Histologically, there was capillariasis of the crop and multifocal ulcerative typhlitis with Heterakis spp. infection, and numerous systemic intravascular monocytes were filled with clusters of blue rod-shaped organisms. The organisms were gram-positive bacilli by Brown and Brenn staining and ultrastructural analysis. Liver bacterial cultures were negative for pathogenic bacteria. Erysipelas septicemia was diagnosed by an Erysipelothrix species-specific polymerase chain reaction method with the substrate DNA isolated from formalin-fixed, paraffin-embedded liver. 相似文献
38.
Richardson JA Gwaltney-Brant SM Albretsen JC Khan SA Porter JA 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2002,16(2):208-210
Zolpidem is a nonbenzodiazepine hypnotic of the imidazopyridine class that is used to treat insomnia in humans. Zolpidem binds selectively to the benzodiazepine omega-1 receptor and increases the frequency of chloride channel opening, which results in inhibition of neuronal excitation. A retrospective study was conducted of zolpidem ingestion in dogs that were reported to the ASPCA Animal Poison Control Center (APCC) between January 1998 and July 2000. Data analysis included amount ingested, clinical effects, and time of onset of signs. Thirty-three reports of zolpidem ingestion in dogs (ranging in age from 5 months to 16 years) were evaluated. Approximate ingested dosages ranged from 0.24 to 21 mg/kg. Clinical signs reported included ataxia (18 dogs; 54.5%), hyperactivity (10 dogs; 30.3%), vomiting (7 dogs; 21.2%), and lethargy (5 dogs; 15.2%), as well as panting, disorientation, nonspecific behavior disorder, and hypersalivation (4 dogs each sign; 12.1%). Other signs reported include tachycardia, tremors, apprehension, vocalization, hypersalivation, weakness, and hyperesthesia. In 85% percent of reports, clinical signs developed within 1 hour and usually resolved within 12 hours. Although central nervous system (CNS) depression is reported as a primary effect of zolpidem in humans and would also be expected in dogs, information obtained from this study indicates that some dogs may exhibit a paradoxical excitation reaction. This effect appears to vary among individual dogs. 相似文献
39.
Polack EW King JM Cummings JF Mohammed HO Birch M Cronin T 《American journal of veterinary research》2000,61(6):609-611
OBJECTIVE: To compare concentrations of trace minerals in the spinal cord of horses with equine motor neuron disease (EMND) with those of horses without neurologic disease (control horses). ANIMALS: 24 horses with EMND and 22 control horses. PROCEDURE: Spinal cord trace mineral concentrations in horses with EMND and control horses were analyzed by use of inductively coupled plasma atomic emission spectroscopy (calcium, phosphorus, sodium, potassium, magnesium, copper, iron, manganese, nickel, zinc, aluminum, cobalt, and chromium), atomic absorption spectrophotometry (lead and cadmium), flameless atomic absorption (mercury), and fluorometry (selenium). RESULTS: Copper concentration was significantly higher in the spinal cord of horses with EMND, compared with control horses; spinal cord concentrations of all other trace minerals were similar between groups. CONCLUSION AND CLINICAL RELEVANCE: Among spinal cord trace minerals investigated in the study, only copper concentrations were significantly different between horses with EMND and horses without neurologic disease, which suggests that copper may be involved in the pathogenesis of EMND. An hypothesis of oxidative injury in this disease is supported by the finding of increased copper concentrations in the spinal cord and by low vitamin E concentrations reported by other researchers. 相似文献
40.
龙胆泻肝汤为中医经典名方,源于清代汪昂《医方集解》,由龙胆草、黄芩、栀子、柴胡、当归、生地黄、木通、车前子、泽泻、甘草10味组成[1]。由于其疗效显著,在临床上被广泛应用。近年来对其药理学、毒理学进行了广泛研究,取得了可喜成绩。1药理学研究1.1中兽医药理论龙胆泻肝汤是以“凉肝猛将”大苦大寒的龙胆草为君,上清肝胆实火,下利三焦湿热,泻火除湿两擅其功;臣以黄芩、栀子泻火;泽泻、木通、车前子除湿,使邪出有路;佐以生地、当归养血益阴,使祛邪不伤正,燥湿不伤阴,并用柴胡疏畅肝胆。综观全方,泻中有补,利中有滋,降中寓升,祛邪不伤正,… 相似文献