全文获取类型
收费全文 | 402篇 |
免费 | 76篇 |
专业分类
林业 | 9篇 |
农学 | 3篇 |
19篇 | |
综合类 | 62篇 |
农作物 | 8篇 |
水产渔业 | 21篇 |
畜牧兽医 | 344篇 |
园艺 | 3篇 |
植物保护 | 9篇 |
出版年
2022年 | 4篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 14篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 15篇 |
2013年 | 15篇 |
2012年 | 29篇 |
2011年 | 17篇 |
2010年 | 6篇 |
2009年 | 19篇 |
2008年 | 21篇 |
2007年 | 18篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 12篇 |
2003年 | 18篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 15篇 |
1990年 | 7篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 9篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1967年 | 6篇 |
1966年 | 4篇 |
排序方式: 共有478条查询结果,搜索用时 31 毫秒
121.
122.
123.
A B-cell, Burkitt-type lymphoma, diffusely affecting the peripheral nerves and intramuscular nerve branches was diagnosed in a 4-year-old domestic shorthair cat with a chronic progressive history of flaccid tetraparesis and generalized muscle atrophy. There was no evidence of cranial nerve, central nervous system, radicular, bone marrow, splenic, or lymph node involvement. The cat tested negative for feline retroviruses and a wide variety of herpes viruses, including Epstein-Barr virus. The clinical manifestation of this case was similar to the chronic polyneuropathic variant of human diffuse neurolymphomatosis; a condition most commonly caused by an axonopathy resulting from infiltration of peripheral nerves with non-Hodgkin's lymphoma. 相似文献
124.
A 5-month-old Hereford calf with neurologic disease was euthanatized, and a necropsy was done. No gross lesions were seen in the brain. Microscopically, neurons throughout the brain and spinal cord had distended, foamy vacuolated cytoplasm. Ultrastructure showed clear vacuoles filling the neuronal cytoplasm. A lysosomal storage disease was suspected. Sphingomyelinase deficiency was confirmed by biochemical analysis of liver and brain. 相似文献
125.
A J Cooley D R Waldron M M Smith G K Saunders G C Troy D L Barber 《Journal of the American Animal Hospital Association》1999,35(4):341-347
The influence of urinary diversion procedures on urethral healing was studied in 15 male dogs following transection and anastomosis of the intrapelvic portions of their urethras. Dogs were randomly assigned to one of three treatment groups and had urine diverted from the surgical site by indwelling transurethral catheter, cystostomy catheter, or a combination of transurethral catheter and cystostomy catheter. There were no statistically significant differences in urethral healing when considering the different diversion methods, based on clinical, radiographic, and urodynamic parameters evaluated. 相似文献
126.
Stephen D. McCormick Richard L. Saunders Arthur D. MacIntyre 《Fish physiology and biochemistry》1989,6(4):231-241
Atlantic salmon (Salmo salar) exposed to either simulated natural photoperiod (SNP) or continuous light (L24) were used to examine developmental changes in the presence and absence, respectively, of the parrsmolt transformation. Plasma osmolarity and ion concentrations were unaffected by photoperiod treatment. Gill Na+, K+-ATPase specific activity increased 150% between February and June in SNP fish and was low and unchanged in L24 fish. Kidney Na+, K+-ATPase specific activity varied within similar, narrow limits in both groups. Citrate synthase of liver, gill and kidney, expressed as specific activity or activity/g total body weight (relative activity), increased 25–60% between March and June in SNP fish. With the exception of kidney relative activity, citrate synthase activity declined to initial (March) levels by August. Liver, gill and kidney cytochrome c oxidase activity of the SNP group underwent similar though less marked changes. Liver, gill and kidney citrate synthase and cytochrome c oxidase activities of the L24 group remained relatively constant between March and August, and where significant differences occurred, they were lower than those of the SNP group. These results indicate that respiratory capacities of the liver, gill and kidney increase in smolls concurrent with preparatory osmoregulatory changes, and subsequently decline. The findings are consistent with a hypothesized transient increase in catabolic activity during the parr-smolt transformation that may be due to the metabolic demands of differentiation. 相似文献
127.
To better understand the factors controlling carbon dioxide (CO2 ) production and transport in soil, we developed a new method to continuously monitor soil CO2 concentration at multiple depths, by using diffusion chambers. The soil diffusion chambers are constructed from a high-density polyethylene cylindrical frame enclosed by a micro-polyvinylidene difluoride flat membrane (PVDF). All chambers are linked to an infrared gas analyser positioned above-ground through a multi-port valve system. We set up two experimental sites for long-term measurements of soil CO2 concentration, soil temperature and soil water content at depths of 0, 10, 20, 40 and 80 cm. The system provides the following advantages : (i) the use of the PVDF combined with the small dimensions of the diffusion chambers allows rapid diffusion of soil gas into the chambers and therefore a short equilibration time of the gas phase with the surrounding soil atmosphere, (ii) the equilibrating closed loop system allows the semi-continuous measurement of soil profile CO2 concentrations without creating a pressure differential within the chambers, thus reducing gas concentration distortions in the soil, (iii) the small size of the closed diffusion chambers reduces the initial soil disturbance during installation, (iv) it allows sampling in wet, humid soils, including ones that are waterlogged or temporarily saturated, and (v) the chambers do not require removal for maintenance purposes and are inexpensive. 相似文献
128.
IgA deficiency in shar-pei dogs 总被引:1,自引:0,他引:1
S D Moroff A I Hurvitz M E Peterson L Saunders K E Noone 《Veterinary immunology and immunopathology》1986,13(3):181-188
Two shar-pei puppies examined because of signs of sinopulmonary disease, one of which also had skin disease, had deficient IgA concentrations. Deficient serum IgA concentrations also were confirmed in 30 of 39 (76.9%) clinically normal adult dogs in two colonies of shar-peis. Both courses of disease--sinopulmonary signs and chronic skin disease and a benign clinical course--have been reported in human patients with IgA deficiency. Thus, the shar-pei might be an appropriate model for studying the immunopathology of IgA deficiency in man. 相似文献
129.
Pigs were immunised intraperitoneally with ovalbumin (OVA) in Freund's complete adjuvant and killed between 52 and 71 days later. Sera, bile and spleen and liver tissue were collected at slaughter. IgG and IgA OVA antibody in bile and serum were detected by ELISA, and IgG and IgA anti-OVA containing cells (AOCC) in tissue were observed using double fluorochrome labelling techniques. The results indicated few IgA AOCC in spleen or liver, but an elevated IgA OVA response in bile compared to serum relative to IgG. The results indicate selective transport of IgA OVA antibody from serum to bile relative to IgG. 相似文献
130.