全文获取类型
收费全文 | 907篇 |
免费 | 44篇 |
专业分类
林业 | 48篇 |
农学 | 25篇 |
130篇 | |
综合类 | 77篇 |
农作物 | 26篇 |
水产渔业 | 39篇 |
畜牧兽医 | 517篇 |
园艺 | 11篇 |
植物保护 | 78篇 |
出版年
2023年 | 6篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 20篇 |
2019年 | 22篇 |
2018年 | 14篇 |
2017年 | 20篇 |
2016年 | 19篇 |
2015年 | 17篇 |
2014年 | 27篇 |
2013年 | 52篇 |
2012年 | 61篇 |
2011年 | 60篇 |
2010年 | 33篇 |
2009年 | 30篇 |
2008年 | 62篇 |
2007年 | 63篇 |
2006年 | 53篇 |
2005年 | 50篇 |
2004年 | 69篇 |
2003年 | 62篇 |
2002年 | 61篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1955年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有951条查询结果,搜索用时 31 毫秒
91.
Crawford PC Levy JK Werner LL 《Journal of the American Veterinary Medical Association》2006,228(7):1038-1041
OBJECTIVE: To identify surrogate markers of passive transfer of immunity in kittens. DESIGN: Prospective clinical trial. ANIMALS: 55 kittens from 12 specific-pathogen-free queens. PROCEDURE: Kittens were allocated at birth into colostrum-fed (n = 27) and colostrum-deprived (28) groups. Blood was collected at birth and on days 1, 2, 4, 7, 14, 28, and 56. Serum samples were analyzed for activities of alkaline phosphatase (ALP), alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, gamma-glutamyltransferase, amylase, and lipase and for concentrations of albumin, total protein, bilirubin, urea nitrogen, creatinine, cholesterol, glucose, calcium, phosphorus, and triglycerides by use of an automated analyzer. Total serum solids concentrations were estimated by use of refractometry. Serum IgG concentrations were quantified by use of radial immunodiffusion. RESULTS: All kittens were agammaglobulinemic at birth. Colostrum-fed kittens had significantly higher IgG concentrations than did colostrum-deprived kittens from 1 though 28 days of age. Transient significant differences in serum biochemical variables between the colostrum-deprived and colostrum-fed groups were substantially resolved by day 4. Passive transfer of immunity could be reliably determined at 1 day of age and to a lesser extent at 2 days of age only by measurement of serum activity of ALP. CONCLUSIONS AND CLINICAL RELEVANCE: Adequacy of passive transfer in kittens initially correlated with serum activity of ALP, but quantification of serum IgG concentration was necessary after 2 days of age. 相似文献
92.
Lord LK Wittum TE Ferketich AK Funk JA Rajala-Schultz P Kauffman RM 《Journal of the American Veterinary Medical Association》2006,229(1):48-54
OBJECTIVE: To examine changes between 1996 and 2004 in regard to numbers of animals handled, medical care provided, expenses, numbers of employees, and agency policies for animal care and control agencies in Ohio. DESIGN: Cross-sectional survey. SAMPLE POPULATION: 223 animal care and control agencies. PROCEDURES: A questionnaire was mailed to animal care and control agencies in Ohio to collect information for 2004; results were compared with published results of a similar survey. RESULTS: 165 of the 223 (74%) agencies responded. Estimated total number of animals handled in 2004 was 315,519, which represented a decrease of 7% compared with 1996. However, although number of dogs taken in decreased 17%, number of cats taken in increased 20%. Between 1996 and 2004, the euthanasia rate decreased from 65.3% to 56.8%, and the adoption rate increased from 24.5% to 33.6%. Number of dogs euthanatized decreased 39%, but number of cats euthanatized increased 14%. The proportion of agencies with a spay-neuter policy increased from 56% to 71%, and the proportion that maintained an association with a veterinarian increased from 39% to 80%. For dogs handled by county dog warden agencies, the odds of euthanasia were higher if the agency did not have a spay-neuter policy (odds ratio, 1.36). CONCLUSIONS: Results suggest that the status of dogs handled by animal care and control agencies in Ohio improved between 1996 and 2004, but that the status of cats deteriorated. 相似文献
93.
Chein-Yao Liao Mei-Ya Chen Yuh-Kun Chen Tien-Cheng Wang Zong-Ming Sheu Ker-Chung Kuo Pi-Fang Linda Chang Kuang-Ren Chung Miin-Huey Lee 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(3):599-608
Colletotrichum acutatum causes anthracnose on peppers (Capsicum spp.), resulting in severe yield losses in Taiwan. Fungal isolates Coll-153, Coll-365 and Coll-524 collected from diseased peppers were found to differ in pathogenicity. Pathogenicity assays on various index plants revealed that Coll-524 was highly virulent and Coll-153 was moderately virulent to three commercially available pepper cultivars. Both isolates induced anthracnose lesions and produced abundant conidia. Coll-365 was only weakly virulent on pepper fruit, where it caused small lesions and hardly produced conidia on pepper fruit. However, Coll-365 was highly pathogenic to tomato fruit and mango leaves, where it caused anthracnose lesions and formed acervuli and conidia. All three isolates showed similar abilities in the attachment and germination of conidia, formation of highly branched hyphae and appressoria, penetration of cuticles, and infection of epidermal cells on chili peppers. Coll-365 accumulated less turgor pressure in appressoria but produced higher levels of cutinase and protease activity than Coll-153 and Coll-524 did. All three isolates invaded the neighbouring cells through plasmodesmata in chili peppers and showed similar pectinase or cellulase activities in culture. However, the most virulent strain Coll-524 expressed stronger laccase activity and was more resistant to capsaicin compared to Coll-153 and Coll-365. The three isolates are different in numbers and sizes of double-stranded RNAs. Depending on the cultivar genotypes, cellular resistance of chili pepper to C. acutatum might rely on the ability to restrict penetration, colonization, or conidiation of the pathogen. We conclude that the differences in pathogenicity among the three C. acutatum isolates of pepper are attributed to their ability to colonize the host plant. 相似文献
94.
Use of cross incompatibility in corn (Zea mays L.) by the Ga1-s allele may reduce cross-fertilization in specialty and conventional organic corn with pollen from genetically-modified (GM)
corn. For effective use, information about environment, and genotype × environment effects on cross-fertilization by ga1 as well as heritability of cross incompatibility in maize is necessary. Our objective was to obtain this information. Four
population pairs differing in their genotype at ga1 were evaluated for cross incompatibility with ga1 pollen in different environments. Populations were derived by crossing the recurrent parents B116, PHG35, ARZM16035:S19,
and (CHZM05015:Mo17)Mo17 to Ga1-s donor parent Mo508W/Mo506W. Two replicates of each treatment were grown in the center of 952 m2 fields planted with purple corn as an adventitious source of ga1/ga1 pollen. Open pollination was allowed and the amount of cross-fertilization estimated by averaging the percentage of purple
seeds. Environment and genotype × environment effects were not significant. Contrasts to evaluate differences in cross-fertilization
between Ga1-s and ga1 populations revealed that mean percentages of cross-fertilization in Ga1-s populations of B116, ARZM16035:S19, and (CHZM05015:Mo17)Mo17 were significantly lower than in ga1 populations. The estimated broad-sense heritability on an entry-mean basis for cross incompatibility was 0.81. Results suggest
differences in genotype at ga1 played a major role in cross-fertilization of populations differing in their genotype at the ga1 locus. Incompatibility may be selected effectively over different environments and the Ga1-s system may be of value to reduce cross-fertilization with GM corn pollen. 相似文献
95.
Michael R. Betz Mark D. Partridge David S. Kraybill Linda Lobao 《Growth and change》2012,43(3):361-391
U.S. states and localities often engage in economic development policies using incentives and abatements for specific firms or industries. Yet, there is very little empirical evidence suggesting that such policies are successful. Why, then, do governments engage in these policies? In order to answer this question, we employ a model that considers not only geographic and economic factors, but also, in a novel application, local political conditions. A unique survey of U.S. county governments forms the basis for our empirical assessment of both traditional economic development policies and new‐wave policies. Using probit, Poisson, negative binomial, and spatial econometric models, we find evidence that the use of incentives is inversely related to local economic conditions. Furthermore, we find Republican counties are more apt to use incentives, though counties dominated by one political party are less likely to use them. 相似文献
96.
Hsu CL Lin W Seshasayee D Chen YH Ding X Lin Z Suto E Huang Z Lee WP Park H Xu M Sun M Rangell L Lutman JL Ulufatu S Stefanich E Chalouni C Sagolla M Diehl L Fielder P Dean B Balazs M Martin F 《Science (New York, N.Y.)》2012,335(6064):89-92
Lysosomal storage diseases (LSDs) are a group of heterogeneous disorders caused by defects in lysosomal enzymes or transporters, resulting in accumulation of undegraded macromolecules or metabolites. Macrophage numbers are expanded in several LSDs, leading to histiocytosis of unknown pathophysiology. Here, we found that mice lacking the equilibrative nucleoside transporter 3 (ENT3) developed a spontaneous and progressive macrophage-dominated histiocytosis. In the absence of ENT3, defective apoptotic cell clearance led to lysosomal nucleoside buildup, elevated intralysosomal pH, and altered macrophage function. The macrophage accumulation was partly due to increased macrophage colony-stimulating factor and receptor expression and signaling secondary to the lysosomal defects. These studies suggest a cellular and molecular basis for the development of histiocytosis in several human syndromes associated with ENT3 mutations and potentially other LSDs. 相似文献
97.
98.
Bryan J Frank LA Rohrbach BW Burgette LJ Cain CL Bemis DA 《Veterinary dermatology》2012,23(4):361-8, e65
Background – The prevalence of meticillin‐ and multidrug‐resistant Staphylococcus pseudintermedius (MRSP) in canine pyoderma has been increasing in recent years; thus, treatment of these cases has become challenging. Hypothesis/Objectives – To compare treatment outcome (clinical resolution and treatment duration), adverse effects of medication, and concurrent diseases and medications in dogs with meticillin‐susceptible S. pseudintermedius (MSSP) and MRSP pyoderma. Animals/Methods – Medical records were reviewed retrospectively, and 123 MSSP and 93 MRSP clinical cases between January 2008 and April 2010 were included. Results – In MSSP infections, cefalexin and cefpodoxime were the most commonly prescribed antimicrobials, accounting for 43.2 and 34.4% of cases, respectively. In MRSP infections, chloramphenicol and doxycycline were most commonly prescribed, accounting for 52.6 and 14.4% of cases, respectively. Adverse effects were reported in seven MSSP and 31 MRSP cases. The most commonly reported adverse effects were gastrointestinal, prompting antibiotic discontinuation in three MSSP and 20 MRSP cases. Chloramphenicol was associated with the highest incidence of adverse reactions (27 of 51 cases). Of 164 cases with follow up, 43 of 88 MSSP infections and 29 of 76 MRSP infections achieved complete clinical resolution at the first recheck examination. Three MSSP and seven MRSP cases failed to improve or resolve at subsequent visits assessed at 3–4 week intervals. Conclusions and clinical importance – Results from this study showed that the majority of pyodermas resolved regardless of meticillin susceptibility. Although some cases of MRSP pyoderma took longer to treat, this is likely to be because of chronicity and not the organism. In addition, adverse effects were frequently associated with chloramphenicol administration. 相似文献
99.
Background – Superficial pyoderma is traditionally considered rare in cats but may be more prevalent than previously reported. Objectives – To better characterize superficial pyoderma in cats. Animals – Fifty‐two cats from a dermatology referral population over a 10 year period. Methods – This study was retrospective. Cases were included if neutrophils and intracellular bacteria were reported from surface cytology of skin lesions. Medical records were reviewed for signalment, historical and clinical data, cytology results, primary skin diagnoses and treatment details. Results – Disease prevalence was 20%, with no breed or sex predispositions. The estimated median age of onset was 2 years, affecting 54% of cats by 3 years and 23% after 9 years. Fewer cases presented during winter (15%) compared with other seasons. Skin lesions were typically multifocal, affecting the face (62%), neck (37%), limbs (33%) and ventral abdomen (29%) most commonly. Crusting (83%), alopecia (67%), ulceration/erosion (54%) and erythema (46%) were common lesion types. Pruritus was reported in 92% of cats. Underlying hypersensitivities (confirmed in 60%; suspected in 19%), and atopic dermatitis specifically (confirmed in 48%), were the most frequent primary dermatoses. Cats were treated with a variety of systemic and/or topical antimicrobials. The overall apparent response was considered good in 61% and poor in 27% of cats. Recurrence was confirmed or suspected in 42% of cats. Conclusions and clinical importance – Feline superficial pyoderma was more prevalent in this study population than previously reported. Young cats with hypersensitivities and older cats were more commonly affected, and a variety of lesion types and distributions occurred. 相似文献
100.
Wellehan JF Pessier AP Archer LL Childress AL Jacobson ER Tesh RB 《Veterinary microbiology》2012,158(3-4):274-279
Rhabdoviruses infect a variety of hosts, including non-avian reptiles. Consensus PCR techniques were used to obtain partial RNA-dependent RNA polymerase gene sequence from five rhabdoviruses of South American lizards; Marco, Chaco, Timbo, Sena Madureira, and a rhabdovirus from a caiman lizard (Dracaena guianensis). The caiman lizard rhabdovirus formed inclusions in erythrocytes, which may be a route for infecting hematophagous insects. This is the first information on behavior of a rhabdovirus in squamates. We also obtained sequence from two rhabdoviruses of Australian lizards, confirming previous Charleville virus sequence and finding that, unlike a previous sequence report but in agreement with serologic reports, Almpiwar virus is clearly distinct from Charleville virus. Bayesian and maximum likelihood phylogenetic analysis revealed that most known rhabdoviruses of squamates cluster in the Almpiwar subgroup. The exception is Marco virus, which is found in the Hart Park group. 相似文献