全文获取类型
收费全文 | 1460篇 |
免费 | 73篇 |
国内免费 | 12篇 |
专业分类
林业 | 201篇 |
农学 | 38篇 |
基础科学 | 6篇 |
435篇 | |
综合类 | 182篇 |
农作物 | 39篇 |
水产渔业 | 63篇 |
畜牧兽医 | 460篇 |
园艺 | 26篇 |
植物保护 | 95篇 |
出版年
2023年 | 9篇 |
2022年 | 9篇 |
2021年 | 30篇 |
2020年 | 23篇 |
2019年 | 24篇 |
2018年 | 48篇 |
2017年 | 33篇 |
2016年 | 46篇 |
2015年 | 47篇 |
2014年 | 48篇 |
2013年 | 83篇 |
2012年 | 95篇 |
2011年 | 106篇 |
2010年 | 77篇 |
2009年 | 62篇 |
2008年 | 99篇 |
2007年 | 87篇 |
2006年 | 73篇 |
2005年 | 55篇 |
2004年 | 87篇 |
2003年 | 57篇 |
2002年 | 47篇 |
2001年 | 25篇 |
2000年 | 16篇 |
1999年 | 13篇 |
1998年 | 9篇 |
1997年 | 14篇 |
1996年 | 17篇 |
1995年 | 8篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1979年 | 4篇 |
1976年 | 4篇 |
1972年 | 6篇 |
1971年 | 8篇 |
1970年 | 5篇 |
1969年 | 5篇 |
1967年 | 4篇 |
1966年 | 5篇 |
1965年 | 8篇 |
1956年 | 3篇 |
1932年 | 4篇 |
1911年 | 6篇 |
排序方式: 共有1545条查询结果,搜索用时 15 毫秒
81.
82.
Cor triatrium dexter with Budd-Chiari syndrome and a review of ascites in young dogs 总被引:1,自引:0,他引:1
C. M. Otto M. Mahaffey C. Jacobs A. Binhazim 《The Journal of small animal practice》1990,31(8):385-389
Ascites with accumulation of a true or modified transudate, is relatively uncommon in young dogs. When it does occur, congenital defects of the cardiovascular, gastrointestinal, or renal systems, infectious diseases and trauma must be considered. Cor triatrium dexter, an abnormal membrane obstructing the caudal vena cava at the level of the right atrium, was diagnosed in an eight-month-old cocker spaniel presented with ascites. 相似文献
83.
C M Otto W J Dodds C E Greene 《Journal of the American Veterinary Medical Association》1991,198(1):129-131
Factor XII deficiency and impaired prekallikrein activity were diagnosed in a 1-year-old Chinese Shar Pei. The dog experienced repeated episodes of intestinal hemorrhage and diarrhea. Laboratory findings were compatible with blood loss (iron deficiency anemia and hypoproteinemia). Necropsy findings suggested mild infiltrative bowel disease that could have been responsible for the dog's diarrhea, but no explanation for the severe recurrent gastrointestinal hemorrhage could be found. Factor XII deficiency is uncommon in the dog and is not associated with hemorrhagic tendencies. The factor XII deficiency in this case may have contributed to the gastrointestinal hemorrhage. 相似文献
84.
D. Otto 《Forstwissenschaftliches Centralblatt》1911,33(10):523-535
Ohne Zusammenfassung 相似文献
85.
Irene Schiller Zen Huat Lu Lloyd Vaughan Roseline Weilenmann Stephane Koundrioukoff Andreas Pospischil 《Journal of veterinary diagnostic investigation》2003,15(6):585-588
Polymerase chain reaction (PCR) from paraffin-embedded tissues provides a powerful tool to amplify DNA from a variety of recent and archival material. Because DNA from paraffin-embedded samples is more degraded than from fresh material, the amplification of reference genes is essential to exclude false-negative results. This study describes the use of the proliferative cell nuclear antigen (PCNA) gene as a reference gene in a range of animal species and in humans. The PCNA-PCR to amplify a fragment extending from exon 5 through exon 6 and including the intervening intron 6 gave a reproducible pattern, with a 280-base pair (bp) band from canine, equine, bovine, ovine, and caprine samples showing high sequence homology. Porcine, guinea pig, tiger, and lion samples, however, gave an additional fragment of approximately 197 bp. The whole intron 6 from these fragments is missing, possibly representing a pseudogene. In feline samples only the 197-bp fragment could be detected. This study shows that the PCNA gene is highly conserved across a broad range of animal species and is well suited as an internal control for PCR analysis in veterinary medicine. 相似文献
86.
87.
88.
89.
Devesa V Loos A Súñer MA Vélez D Feria A Martínez A Montoro R Sanz Y 《Journal of agricultural and food chemistry》2005,53(26):10297-10305
A study of the transformation of arsenic species by the microflora of the freshwater crayfish Procambarus clarkii was carried out. The study of the degradation of AB (arsenobetaine) was performed in aerobic conditions in two culture media (tryptic soy broth and saline medium) at two temperatures (30 and 8 degrees C). The microflora transformed AB into TMAO (trimethylarsine oxide), DMA (dimethylarsinate), MA (methylarsonate), and an unidentified compound (U1). The quickest transformations were carried out by microflora from hepatopancreas incubated in saline medium at 30 degrees C. The individualized study of other arsenic species [AC (arsenocholine), TETRA (tetramethylarsonium ion), TMAO, DMA, and MA] was also performed in saline medium. The only transformation observed was of AC into AB. The bacteria possibly responsible for AB degradation were isolated, identified by phenotypic and genotypic methods, and individually assayed for AB transformation. Only isolates allocated to the species Pseudomonas putida were able to metabolize AB. 相似文献
90.
Lars A. Knechtenhofer Irene O. Xifra Andreas C. Scheinost Hannes Flühler Ruben Kretzschmar 《植物养料与土壤学杂志》2003,166(1):84-92
To assess the mobility of Pb and associated metals in a highly contaminated shooting range soil (Losone, Ticino, Switzerland), we investigated the spatial distribution of the metals and their relation to preferential water flow paths. A 2.2 m2 plot located 40 m behind the stop butt was irrigated with a solution containing bromide and Brilliant Blue, a slightly sorbing dye. A soil profile 50 cm in width was sampled down to 80 cm with a spatial resolution of 2.5 cm, resulting in 626 samples. Concentrations of elements (12 ≤ Z ≤ 92) were determined by energy‐dispersive Xray fluorescence spectrometry, and Brilliant Blue concentrations were determined with a chromameter. In the acidic (pH 3), organic matter‐rich, well drained Dystric Cambisol, maximum concentrations of 80.9 g kg‐1 Pb, 4.0 g kg‐1 Sb, and 0.55 g kg‐1 Cu were measured in the topsoil. Within 40 cm soil depth, however, Pb, Sb, and Cu approached background concentrations of 23 mg kg‐1, 0.4 mg kg‐1, and 9.4 mg kg‐1, respectively. The even horizontal distribution and the steep gradient along soil depth indicate tight metal binding in the topsoil, and a fairly homogeneous transport front. In contrast, water flow through the profile was highly heterogeneous. In the uppermost 20 cm, preferential flow was initiated by heterogeneous infiltration at the soil surface, but had no influence on metal distribution. Below 20 cm, however, preferential flow originated from larger tree roots, and metal concentrations were significantly elevated along these macropores. Spatial distributions of Pb, Sb, and Cu were similar, suggesting that all three metals are strongly retained in the topsoil and transported along preferential water flow paths in the subsoil. 相似文献