全文获取类型
收费全文 | 6333篇 |
免费 | 213篇 |
国内免费 | 3篇 |
专业分类
林业 | 2627篇 |
农学 | 79篇 |
基础科学 | 9篇 |
538篇 | |
综合类 | 301篇 |
农作物 | 274篇 |
水产渔业 | 188篇 |
畜牧兽医 | 2119篇 |
园艺 | 87篇 |
植物保护 | 327篇 |
出版年
2020年 | 64篇 |
2019年 | 60篇 |
2018年 | 68篇 |
2017年 | 77篇 |
2016年 | 76篇 |
2015年 | 76篇 |
2014年 | 96篇 |
2013年 | 232篇 |
2012年 | 176篇 |
2011年 | 215篇 |
2010年 | 98篇 |
2009年 | 146篇 |
2008年 | 168篇 |
2007年 | 168篇 |
2006年 | 170篇 |
2005年 | 201篇 |
2004年 | 187篇 |
2003年 | 162篇 |
2002年 | 139篇 |
2001年 | 78篇 |
2000年 | 76篇 |
1999年 | 65篇 |
1997年 | 72篇 |
1996年 | 91篇 |
1995年 | 66篇 |
1994年 | 64篇 |
1993年 | 79篇 |
1992年 | 92篇 |
1991年 | 76篇 |
1990年 | 66篇 |
1989年 | 63篇 |
1988年 | 56篇 |
1987年 | 58篇 |
1986年 | 68篇 |
1984年 | 74篇 |
1983年 | 72篇 |
1982年 | 72篇 |
1981年 | 112篇 |
1980年 | 64篇 |
1979年 | 113篇 |
1978年 | 60篇 |
1953年 | 66篇 |
1938年 | 60篇 |
1936年 | 53篇 |
1935年 | 51篇 |
1934年 | 51篇 |
1933年 | 56篇 |
1932年 | 53篇 |
1926年 | 74篇 |
1925年 | 57篇 |
排序方式: 共有6549条查询结果,搜索用时 562 毫秒
51.
52.
Validation of the Accutrend Plus point‐of‐care triglyceride analyzer in horses,ponies, and donkeys
下载免费PDF全文
![点击此处可从《Journal of Veterinary Emergency and Critical Care》网站下载免费的PDF全文](/ch/ext_images/free.gif)
53.
54.
Clinicopathological Phenotype of Autosomal Recessive Cholesterol Deficiency in Holstein Cattle
下载免费PDF全文
![点击此处可从《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
55.
Fixed‐time Insemination in Pasture‐based Medium‐sized Dairy Operations of Northern Germany and an Attempt to Replace GnRH by hCG
下载免费PDF全文
![点击此处可从《Reproduction in domestic animals》网站下载免费的PDF全文](/ch/ext_images/free.gif)
D Marthold J Detterer U Koenig von Borstel M Gauly W Holtz 《Reproduction in domestic animals》2016,51(1):85-90
A field study was conducted aimed at (i) evaluating the practicability of a fixed‐time insemination regime for medium‐sized dairy operations of north‐western Germany, representative for many regions of Central Europe and (ii) substituting hCG for GnRH as ovulation‐inducing agent at the end of a presynch or ovsynch protocol in an attempt to reduce the incidence of premature luteal regression. Cows of two herds synchronized by presynch and two herds synchronized by ovsynch protocol were randomly allotted to three subgroups; in one group ovulation was induced by the GnRH analog buserelin, in another by hCG, whereas a third group remained untreated. The synchronized groups were fixed‐time inseminated; the untreated group bred to observed oestrus. Relative to untreated herd mates, pregnancy rate in cows subjected to a presynch protocol with buserelin as ovulation‐inducing agent was 74%; for hCG it was 60%. In cows subjected to an ovsynch protocol, the corresponding relative pregnancy rates reached 138% in the case of buserelin and 95% in the case of hCG. Average service interval was shortened by 1 week in the presynch and delayed by 2 weeks in the ovsynch group. It may be concluded that fixed‐time insemination of cows synchronized via ovsynch protocol with buserelin as ovulation‐inducing agent is practicable and may help improve efficiency and reduce the work load involved with herd management in medium‐sized dairy operations. The substitution of hCG for buserelin was found to be not advisable. 相似文献
56.
Licht BG Lin S Luo Y Hyson LL Licht MH Harper KM Sullivan SA Fernandez SA Johnston EV 《Journal of the American Veterinary Medical Association》2007,231(10):1520-1528
OBJECTIVE: To determine clinical characteristics and mode of inheritance of seizures in a family of Standard Poodles. DESIGN: Case series. ANIMALS: 90 Standard Poodles descended from the same maternal bloodline (30 with probable idiopathic epilepsy [PIE] and 60 without any history of seizures). PROCEDURES: Researchers contacted owners to determine whether dogs had ever had any seizures and, if so, the nature of any such seizures and any potential underlying causes. Dogs were considered to have PIE if they were between 6 months and 7.5 years old at the time of seizure onset and had no evidence of any underlying cause. To determine the mode of inheritance, segregation analyses were designed to allow the family to be analyzed as a whole, as opposed to as nuclear families. Competing models of inheritance were compared statistically for their ability to explain the data. RESULTS: Of the dogs with PIE, 28 (93%) had focal onset seizures with or without secondary generalization. Median age of onset was 3.7 years; 6 dogs were > 5 years old at the onset of seizures. Segregation analyses strongly suggested that PIE was inherited as a simple recessive autosomal trait with complete or almost complete penetrance. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in this family of Standard Poodles, PIE was inherited as a simple recessive autosomal trait with complete or almost complete penetrance. Seizures often had focal, as opposed to generalized, onsets, and it was not uncommon for seizures to begin after 5 years of age. 相似文献
57.
Buchholz J Wergin M Walt H Gräfe S Bley CR Kaser-Hotz B 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(4):770-775
BACKGROUND: Squamous cell carcinomas are common skin tumors in cats. We investigated photodynamic therapy (PDT) using a new liposomal photosensitizer as a minimally invasive, effective treatment that can be easily performed while achieving good cosmetic results. AIM: The goal of this study was to assess and describe possible toxicities using a liposomal formulation of the photosensitizer meta-(Tetrahydroxyphenyl)Chlorin (m-THPC) and investigate if favorable pharmacokinetics translate into favorable tumor response and control. ANIMALS: Eighteen client-owned cats with 20 spontaneous cutaneous squamous cell carcinomas were included in the study. METHODS: PDT was performed using a new, liposomal formulation of the photosensitizer. Toxicity, tumor response, and tumor control were evaluated retrospectively. RESULTS: No general adverse effects were observed in cats treated with the new liposomal formulation. Mild local toxicity such as erythema and edema were seen in 15% of the patients. All cats responded to therapy, with a complete response rate of 100%. The overall 1-year control rate was 75%. The tumor recurrence rate was 20% with a median time to recurrence of 172.25 +/-87.1) days. CONCLUSIONS AND CLINICAL IMPORTANCE: A new liposomal photosensitizer was successfully used for squamous cell carcinoma in cats and was well tolerated. There were no systemic adverse effects observed with the liposomal formulation. The favorable pharmacokinetics of the liposomal drug resulted in a favorable tumor response. 相似文献
58.
Diniz PP Maggi RG Schwartz DS Cadenas MB Bradley JM Hegarty B Breitschwerdt EB 《Veterinary research》2007,38(5):697-710
The purpose of this study was to determine the serological and molecular prevalence of Bartonella spp. infection in a sick dog population from Brazil. At the S?o Paulo State University Veterinary Teaching Hospital in Botucatu, 198 consecutive dogs with clinicopathological abnormalities consistent with tick-borne infections were sampled. Antibodies to Bartonella henselae and Bartonella vinsonii subsp. berkhoffii were detected in 2.0% (4/197) and 1.5% (3/197) of the dogs, respectively. Using 16S-23S rRNA intergenic transcribed spacer (ITS) primers, Bartonella DNA was amplified from only 1/198 blood samples. Bartonella seroreactive and/or PCR positive blood samples (n=8) were inoculated into a liquid pre-enrichment growth medium (BAPGM) and subsequently sub-inoculated onto BAPGM/blood-agar plates. PCR targeting the ITS region, pap31 and rpoB genes amplified B. henselae from the blood and/or isolates of the PCR positive dog (ITS: DQ346666; pap31 gene: DQ351240; rpoB: EF196806). B. henselae and B. vinsonii subsp. berkhoffii (pap31: DQ906160; rpoB: EF196805) co-infection was found in one of the B. vinsonii subsp. berkhoffii seroreactive dogs. We conclude that dogs in this study population were infrequently exposed to or infected with a Bartonella species. The B. henselae and B. vinsonii subsp. berkhoffii strains identified in this study are genetically similar to strains isolated from septicemic cats, dogs, coyotes and human beings from other parts of the world. To our knowledge, these isolates provide the first Brazilian DNA sequences from these Bartonella species and the first evidence of Bartonella co-infection in dogs. 相似文献
59.
Maria Caridad Montalvo Villalba Chantal J. Snoeck Licel de los Angeles Rodriguez Lay Aurélie Sausy Dayesi Hernández López Marite Bello Corredor Barbara Marrero Sanchéz Judith M. Hübschen 《Zoonoses and public health》2023,70(1):58-68
Surveillance of hepatitis E virus (HEV) in risk groups is an important strategy to monitor its circulation pattern and to timely detect changes thereof. The aims of this cross-sectional study were to estimate the prevalence of HEV infections in pigs and humans from different regions of the country, to identify risk factors for increasing anti-HEV IgG prevalence and to characterize HEV strains. The presence of anti-HEV antibodies was assessed by commercial ELISA in serum samples from the general population, farm and slaughterhouse employees, as well as pigs sampled in the three regions of Cuba from February to September 2016. Overall, individuals with occupational exposure to swine or swine products (70/248, 28.2%) were 4 times more likely to be seropositive compared to the general population (25/285, 8.7%; OR: 4.18; p < .001). Within the risk group, risk factors included age, number of years working in a professional activity with direct exposure to swine, geographic region and distance between residence and closest professional swine setting, while wearing gloves had a protective effect. Prevalence of total anti-HEV antibodies in swine was 88.2% (165/187) and HEV RNA was detected by real-time RT-PCR in 9.2% (16/173) swine stools. All HEV strains sequenced clustered within genotype 3. Some strains clearly belonged to subtype 3a, while another group of strains was related with subtypes 3b and 3 k but partial HEV sequences did not allow unequivocal subtype assignment. These findings suggest that the high HEV exposure in Cuban individuals with swine-related occupations could be due to enzootic HEV in certain regions, direct contact with infectious animals or their products as well as environmental contamination. 相似文献
60.
M. Ryan Smith DVM DACVECC Virginie A. Wurlod MS Dr vet med DACVECC DECVECC Chin-Chi Liu MS MApStat PhD 《Journal of Veterinary Emergency and Critical Care》2023,33(6):648-655