全文获取类型
收费全文 | 5737篇 |
免费 | 408篇 |
国内免费 | 3篇 |
专业分类
林业 | 149篇 |
农学 | 123篇 |
基础科学 | 50篇 |
642篇 | |
综合类 | 1464篇 |
农作物 | 192篇 |
水产渔业 | 224篇 |
畜牧兽医 | 3056篇 |
园艺 | 62篇 |
植物保护 | 186篇 |
出版年
2020年 | 48篇 |
2019年 | 49篇 |
2018年 | 70篇 |
2017年 | 66篇 |
2016年 | 77篇 |
2015年 | 55篇 |
2014年 | 87篇 |
2013年 | 228篇 |
2012年 | 165篇 |
2011年 | 184篇 |
2010年 | 104篇 |
2009年 | 102篇 |
2008年 | 202篇 |
2007年 | 197篇 |
2006年 | 203篇 |
2005年 | 180篇 |
2004年 | 177篇 |
2003年 | 187篇 |
2002年 | 159篇 |
2001年 | 140篇 |
2000年 | 167篇 |
1999年 | 142篇 |
1998年 | 54篇 |
1997年 | 51篇 |
1995年 | 48篇 |
1992年 | 121篇 |
1991年 | 123篇 |
1990年 | 119篇 |
1989年 | 114篇 |
1988年 | 97篇 |
1987年 | 94篇 |
1986年 | 135篇 |
1985年 | 152篇 |
1984年 | 119篇 |
1983年 | 113篇 |
1982年 | 70篇 |
1981年 | 83篇 |
1980年 | 65篇 |
1979年 | 110篇 |
1978年 | 98篇 |
1977年 | 59篇 |
1976年 | 50篇 |
1975年 | 54篇 |
1974年 | 57篇 |
1973年 | 77篇 |
1972年 | 77篇 |
1971年 | 67篇 |
1970年 | 56篇 |
1969年 | 62篇 |
1968年 | 62篇 |
排序方式: 共有6148条查询结果,搜索用时 15 毫秒
31.
32.
Mastrorilli C Spangler EA Christopherson PW Aubry OA Newton JC Smith AN Kennis RA Weismann JL Moore PF 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2012,41(3):412-418
A 9‐month‐old male Great Dane had progressive generalized nodular dermatopathy for several months. There were > 100 raised, alopecic, firm, painful nodules throughout the skin. Aspirates from several lesions yielded moderate numbers of irregularly round or polygonal to spindle‐shaped cells with mild to moderate anisocytosis and few inflammatory cells, and the cytologic interpretation was proliferation of mesenchymal or histiocytic cells. On histopathologic examination, nodules were composed of densely packed sheets of round to spindle‐shaped cells with mild anisokaryosis and low mitotic activity. Multifocal histiocytic sarcoma with a spindle‐cell pattern was diagnosed based on morphologic features and intense expression of CD18. Additional immunophenotypic analysis on frozen sections of tissue confirmed the diagnosis of histiocytic sarcoma; expression of CD18, CD45, CD1a, CD11b, and CD11c, limited expression of Thy‐1 (CD90) and CD80, and lack of expression of CD4, CD11d, and CD86 indicated that the cells were likely interstitial dendritic cells; a review of reactive and neoplastic dendritic cells is provided. Based on staging, internal organs were not affected. Sequential treatment with lomustine and doxorubicin failed to prevent progression of the cutaneous lesions, and the dog died 3 months after initial diagnosis. At necropsy, a focus of neoplastic cells was present in one lymph node, but except for skin other organs were not involved. The clinical presentation of histiocytic sarcoma may be unusual, and neoplastic cells may lack overt features of malignancy on cytologic and histopathologic examination. In some instances, immunophenotyping is required to differentiate histiocytic sarcoma from other histiocytic disorders. 相似文献
33.
A ventral abdominal subcutaneous mass was removed from each of 2 young adult spayed female ferrets. In both cases, the neoplasms were composed of islands of polygonal cells separated by interlacing streams of spindloid cells reminiscent of ferret adrenocortical tumors with smooth muscle proliferation. Immunohistochemically, the polygonal cells demonstrated strong cytoplasmic reactivity for inhibin and weak cytoplasmic reactivity for pancytokeratin and S-100 protein. Spindloid cells demonstrated strong cytoplasmic reactivity for alpha smooth muscle actin, muscle-specific actin, desmin, and glial fibrillary acidic [corrected] protein. Ultrastructurally, the polygonal cells contained numerous intracytoplasmic clear vacuoles, mitochondria, scant rough endoplasmic reticulum, and few intermediate filaments. In one tumor, vesicular tubular mitochondria were found in polygonal cells. The spindloid cells contained numerous aggregates of parallel intermediate filaments. The histologic, immunohistochemical, and ultrastructural findings are suggestive of adrenocortical tumors with smooth muscle proliferation, but cannot be differentiated from an ovarian gonadal stromal tumor. Neither ferret had a clinically detected primary adrenal gland tumor or clinical signs of adrenal-associated endocrinopathy. 相似文献
34.
M.A. McMichael M. O'Brien S.A. Smith 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(2):499-504
Background
Blastomycosis is a potentially fatal fungal disease that most commonly affects humans and dogs. The organism causes systemic inflammation and has a predilection for the lungs. The inflammation might lead to a hypercoagulable state with microemboli in the pulmonary circulation which could contribute to inadequate oxygen exchange in infected dogs.Hypothesis/Objectives
Dogs with blastomycosis will be hypercoagulable compared with healthy case‐matched controls.Animals
Client‐owned dogs with a diagnosis of blastomycosis (n = 23) and healthy case‐matched controls (n = 23).Methods
Prospective case‐controlled study of client‐owned dogs presented to a veterinary teaching hospital with clinical signs compatible with blastomycosis. Complete blood counts, fibrinogen, PT, aPTT, thromboelastometry (TE), thrombin antithrombin complexes (TAT), and thrombin generation were evaluated.Results
Cases had a leukocytosis compared with controls [mean (SD) 16.6 (7.6) × 103/μL versus 8.2 (1.8) × 103/μL, P < .001], hyperfibrinogenemia [median 784 mg/dL, range 329–1,443 versus median 178 mg/dL, range 82–257, P < .001], and increased TAT concentrations [mean (SD) 9.0 (5.7) μg/L versus 2.0 (2.8) μg/L, P < .001]. As compared to controls, cases were also hypercoagulable as evaluated by thromboelastometry and had increased in vitro thrombin generation on calibrated automated thrombography.Conclusions and Clinical Importance
Hypercoagulability occurs in dogs with systemic blastomycosis. Additional studies are needed to explore a possible contribution of thrombogenicity to the clinical manifestations of systemic blastomycosis. 相似文献35.
36.
G Fecteau J G Zinkl B P Smith S O'Neil S Smith S Klopfer 《The Canadian veterinary journal. La revue veterinaire canadienne》1997,38(7):443-444
Hereditary fibrinogen deficiency is a rare condition in all species. Measurement of plasma fibrinogen should indicate low levels. Specific factor assays and pedigree analysis are essential in establishing a definitive diagnosis of the hereditary deficiency. Differentiation between afibrinogenemia, hypofibrinogenemia, and dysfibrinogenemia requires sophisticated techniques and assistance from a specialized laboratory. 相似文献
37.
Packages (n = 660) of clod, strip loin, tenderloin, bottom round, eye-of-round, and top round steaks, as well as ground beef, from beef cattle fed diets supplemented with vitamin E (500 IU/d for 100 d preharvest) were compared with packages of products derived from carcasses of beef cattle fed control diets to determine the duration of acceptable muscle color during simulated retail display. In addition, the effect of storage before steak fabrication, simulating distribution time, on the acceptability of each treatment and each cut during retail display was investigated. Dietary supplementation of animals with vitamin E increased muscle alpha-tocopherol concentrations (P < .05) in all cuts. The acceptable retail display time of ground beef from vitamin E-supplemented cattle was longer (P < .05) compared to ground beef from unsupplemented cattle by 10.2, 15.6, and 17.6 h following 7, 14, and 21 d of storage in chub packages prior to final grinding and retail display, respectively. However, length of storage in a vacuum package before retail display did not have a consistent effect on retail case life of steaks. Product drip loss during retail display was not affected by storage time or vitamin E treatment. The trained panel color score during retail display of high vitamin E strip loin, bottom round, inside round, and eye-of-round steaks remained acceptable longer (P < .05) by 11.5, 25.2, 8.4, and 29.4 h, respectively, than that of control steaks. The results demonstrated that vitamin E supplementation of cattle feed can be used as a management tool to reduce the economic losses associated with beef muscle color deterioration during retail display of products. 相似文献
38.
39.
40.