全文获取类型
收费全文 | 6771篇 |
免费 | 3379篇 |
国内免费 | 1篇 |
专业分类
林业 | 214篇 |
农学 | 441篇 |
基础科学 | 2篇 |
1368篇 | |
综合类 | 62篇 |
农作物 | 119篇 |
水产渔业 | 2542篇 |
畜牧兽医 | 4115篇 |
园艺 | 12篇 |
植物保护 | 1276篇 |
出版年
2024年 | 3篇 |
2023年 | 10篇 |
2022年 | 16篇 |
2021年 | 147篇 |
2020年 | 497篇 |
2019年 | 1038篇 |
2018年 | 909篇 |
2017年 | 952篇 |
2016年 | 942篇 |
2015年 | 822篇 |
2014年 | 813篇 |
2013年 | 978篇 |
2012年 | 490篇 |
2011年 | 499篇 |
2010年 | 610篇 |
2009年 | 264篇 |
2008年 | 231篇 |
2007年 | 95篇 |
2006年 | 103篇 |
2005年 | 98篇 |
2004年 | 103篇 |
2003年 | 102篇 |
2002年 | 112篇 |
2001年 | 74篇 |
2000年 | 102篇 |
1999年 | 10篇 |
1997年 | 15篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1970年 | 4篇 |
1968年 | 2篇 |
1965年 | 3篇 |
1963年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The vertebral heart score (VHS) measurement is commonly used to provide a more objective measurement of cardiomegaly in canines. However, several studies have shown significant breed variations from the value previously established by Buchanan and Bücheler (9.7 ± 0.5). This study describes VHS measurements in Pug, Pomeranian, Yorkshire Terrier, Dachshund, Bulldog, Shih Tzu, Lhasa Apso, and Boston Terrier dog breeds. Dogs with two or three view thoracic radiographs, no subjective radiographic evidence of cardiomegaly, and no physical examination findings of heart murmurs or gallop rhythms were included in the study. The Pug, Pomeranian, Bulldog, and Boston Terrier groups were found to have a VHS significantly greater than 9.7 ± 0.5 (P < 0.00001, P = 0.0014, P < 0.0001, P < 0.00001, respectively). Body condition score (BCS) was found to have a significant effect on the VHS of Lhasa Apso group. Anomalous vertebrae in the thoracic column were associated with a significant increase in VHS of the Bulldog (P = 0.028) and Boston Terrier (P = 0.0004) groups. Thoracic depth to width ratio did not have a significant effect on VHS. 相似文献
72.
A. Kovačić I. Listeš C. Vučica L. Kozačinski I. Tripković K. Šiško‐Kraljević 《Zoonoses and public health》2013,60(4):269-276
Consumption of poultry contaminated with Campylobacter jejuni has been recognized worldwide as the leading cause of campylobacteriosis. Therefore, the aim of our study was to investigate the prevalence and genotype diversity of Campylobacter jejuni in poultry meat intended for consumption in Split and Dalmatia County, which is the second biggest County in Croatia. Furthermore, we also wanted to discover possibly stable clones of C. jejuni appearing in different samples and periods of time, which would indicate their ability to persist in or adapt to poultry. In the period from March 2008 until June 2010, 834 samples of poultry from various sources were examined using a surface swab technique. Isolation of C. jejuni was performed by Preston broth and Karmali agar. Identification of the isolates was carried out using biochemical tests. C. jejuni was found in 84 of 574 chicken samples (14.6%) and in nine of 260 samples of turkey (3.5%). Pulse‐field gel electrophoresis (PFGE) was used to analyse 61 obtained isolates using SmaI and KpnI. Of 22 different macrorestriction profiles (MRP) that were found, five were detected in poultry from both different locations and periods of time. Samples from 11 locations were found to be contaminated with more than two different genotypes of C. jejuni. Interestingly, the same MRP were found both in poultry declared to be of domestic origin and in the poultry imported from abroad. The prevalence of C. jejuni in poultry samples was in accordance with previously reported results. Genotypic analysis indicated that the population of C. jejuni in Split and Dalmatia County was diverse and that multiple strains of C. jejuni could be found in the same poultry samples. Furthermore, the same genotypes were identified from the samples obtained from different locations and periods of time, which could support the theory of a global existence of certain MRP that are able to persist in or adapt to poultry. 相似文献
73.
Effect of injecting amino acids into the egg on embryonic and subsequent growth in the domestic fowl
W. K. Al‐Murrani 《British poultry science》1982,23(2):171-174
1. The growing embryo uses about 1% of the total protein available in the egg during the first week of incubation.
2. Injecting the growing embryo with amino acids equivalent to the amount of protein used resulted in higher weight of chicks at all stages up to 56 d. 相似文献
74.
V. Villar B. Colao I. Calles‐Venal J. G. Fernndez‐lvarez M. Fernndez‐Caso J. M. Villar 《Anatomia, histologia, embryologia》2005,34(Z1):54-54
Chondrocytes dedifferentiate to a fibroblast‐like phenotype on plastic surfaces. Dedifferentiation is reversible if these cells are then cultured embedded in gels as alginate, agarose or collagen. Chondrocytes cultured in suspension on a non‐adherent surface are also known to form aggregates of differentiated cells. The knowledge of chondrocyte behavior in culture is relevant for tissue engineering purposes. In this report we describe a simple method to culture differentiated or redifferentiated rabbit auricular chondrocytes on plastic surfaces with a stable phenotype. When chondrocyte aggregates formed in suspension are next seeded on plastic surfaces, most of them attach to the plastic as round or polygonal cells, and this morphological differentiation, confirmed by the presence of type II collagen, is stable for long culture periods. We also report that the addition of aggregates to monolayer cultures of dedifferentiated chondrocytes results in their redifferentiation, as is shown by their morphological changes and the synthesis of type II collagen. Therefore, this simple method can be useful for the study of chondrocyte behavior on plastic surfaces and for redifferentiating previously proliferated chondrocytes in tissue engineering techniques. Furthermore, these results demonstrate that, in addition to culture conditions such as cell isolation method or cell‐density, chondrocyte behavior on plastic depends on the presence or absence of aggregates resulting from the dissociation process. 相似文献
75.
Nonregenerative immune‐mediated anemia associated with a diffuse large B‐cell lymphoma in a captive jaguar (Panthera onca) 下载免费PDF全文
Monika A. Keresztes Manfred Henrich Penelope Baloi Sascha Gerst Jens‐Christian Rudnick Judith Langenstein Andreas Moritz Natali Bauer 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2017,46(4):597-604
An 18‐year‐old male castrated jaguar (Panthera onca) was presented with anorexia and continuous bleeding from the oral cavity after a history of fighting with the partner animal. Clinical evaluation revealed ulcerating lesions on the gingiva and hard palate and a hematoma on the tongue. Computed tomography of the head and endoscopic examination of the esophagus and stomach were unremarkable. Hematology and clinical chemistry revealed severe nonregenerative anemia, mild thrombocytopenia, and moderate azotemia. Several PCRs for feline hemotropic mycoplasmas (Mycoplasma haemofelis, M heamominutium, M turicensis), Babesia felis, and Bartonella spp., as well as an FeLV antigen test were negative. The cytologic examination of a bone marrow aspirate was consistent with ineffective erythropoiesis, most likely due to immune‐mediated destruction of the erythroid precursor cells. Prednisolone therapy was initiated (1.25 mg/kg/day), and the CBC returned to normal 16 days after the initiation of the therapy. Anemia relapsed after 4 months and severe splenomegaly was noted. A repeat bone marrow aspirate revealed active erythropoiesis in the presence of erythroid precursor phagocytosis suggesting an immune‐mediated process. Splenic fine‐needle aspiration and tissue biopsies were taken, and all findings including histology and immunohistochemistry were consistent with a diffuse large B‐cell lymphoma (DLBCL). Five days later, the clinical condition deteriorated and the jaguar died. Histopathology following necropsy showed infiltration with neoplastic lymphoblasts in the spleen, liver, and abdominal lymph nodes. This case report describes a nonregenerative immune‐mediated anemia associated with a DLBCL in a jaguar. 相似文献
76.
K. Blanco‐Peña F. Esperón A. M. Torres‐Mejía A. de la Torre E. de la Cruz M. Jiménez‐Soto 《Zoonoses and public health》2017,64(7):e23-e30
Antimicrobial resistance is known to be an emerging problem, but the extent of the issue remains incomplete. The aim of this study was to determine the presence or absence of nine resistance genes (blaTEM, catI, mecA, qnrS, sulI, sulII, tet(A), tet(Q), vanA) in the faeces of 141 pigeons from four urban parks in Alajuela, Guadalupe, Tres Ríos and San José in Costa Rica. The genes were identified by real‐time PCR directly from enema samples. About 30% of the samples were positive for genes catI and sulI; between 13% and 17% were positive for qnrS, sulII, tet(A) and tet(Q); and 4% were positive for blaTEM. The mecA and vanA genes were not detected. The average of antimicrobial resistance genes detected per pigeon was 2. Eight different patterns of resistance were identified, without differences in the sampling areas, being the most common pattern 2 (sulII positive samples). During rainy season, the genes more frequently found were sulI and tet(A). In conclusion, the urban inhabiting pigeons tested are currently carrying antimicrobial resistance genes, potentially acting as reservoirs of resistant bacteria and vectors to humans. To the authors’ knowledge, this is the first study carried out on direct detection of resistance genes in the digestive metagenomes of pigeons. 相似文献
77.
78.
79.
80.