首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   195篇
  免费   28篇
  国内免费   1篇
林业   1篇
农学   5篇
基础科学   1篇
  3篇
综合类   21篇
农作物   8篇
水产渔业   2篇
畜牧兽医   172篇
园艺   1篇
植物保护   10篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2020年   5篇
  2019年   4篇
  2018年   5篇
  2017年   6篇
  2016年   8篇
  2015年   9篇
  2014年   9篇
  2013年   34篇
  2012年   7篇
  2011年   8篇
  2010年   4篇
  2009年   6篇
  2008年   3篇
  2007年   6篇
  2006年   5篇
  2005年   7篇
  2004年   9篇
  2003年   3篇
  2001年   6篇
  2000年   2篇
  1999年   6篇
  1998年   5篇
  1997年   3篇
  1996年   4篇
  1995年   2篇
  1994年   5篇
  1993年   4篇
  1992年   6篇
  1991年   6篇
  1990年   2篇
  1989年   4篇
  1988年   5篇
  1987年   2篇
  1986年   4篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1967年   3篇
  1954年   1篇
  1953年   2篇
  1952年   3篇
  1951年   1篇
  1950年   1篇
  1949年   1篇
  1947年   1篇
排序方式: 共有224条查询结果,搜索用时 0 毫秒
81.
82.
In spite of widespread application of flutamide in the endocrine therapies of young and adult patients, the side effects of this antiandrogen on spermatogenesis and germ‐cell morphology remain unclear. This study evaluates the short‐term androgen blockage effect induced by the administration of flutamide to the testes of pubertal (30‐day old) and adult (65‐ and 135‐day old) guinea pigs, with an emphasis on ultrastructural alterations of main cell types. The testes removed after 10 days of treatment with either a non‐steroidal antiandrogen, flutamide (10 mg/kg of body weight) or a pharmacological vehicle alone were processed for histological, quantitative and ultrastructural analysis. In pubertal animals, flutamide androgenic blockage induces spermatogonial differentiation and accelerates testes maturation, causing degeneration and detachment of primary spermatocytes and round spermatids, which are subsequently found in great quantities in the epididymis caput. In post‐pubertal and adult guinea pigs, in addition to causing germ‐cell degeneration, especially in primary spermatocytes, and leading to the premature detachment of spherical spermatids, the antiandrogen treatment increased the relative volume of Leydig cells. In addition, ultrastructural evaluation indicated that irrespective of age antiandrogen treatment causes an increase in frequency of organelles involved with steroid hormone synthesis in the Leydig cells and a dramatic accumulation of myelin figures in their cytoplasm and, to a larger degree, in Sertoli cells. In conclusion, the transient exposition of the guinea pigs to flutamide, at all postnatal ages causes some degenerative lesions including severe premature detachment of spermatids and accumulation of myelin bodies in Leydig and Sertoli cells, compromising, at least temporarily, the spermatogenesis.  相似文献   
83.
Two six-week-old intact Welsh terrier littermates, a male and a female, were presented for congenital ventral thoracic wall deformities characterised by noticeable funnel-like depressions of the cranial sternum associated with inversion of the rib cage. No exercise intolerance or cardiac murmurs were noted. Thoracic radiographic examination revealed a significant dorsal deviation of the first to the fifth sternebrae. At 12 weeks of age, the thoracic depressions had improved markedly in both puppies. Thoracic radiography to reassess the sternal deviation was at this stage within normal limits, demonstrating complete radiographic resolution of the sternal deformity.  相似文献   
84.
Objective To determine if systemic administration of lidocaine during intraocular surgery reduces post-operative ocular pain. Study design Randomized, masked, controlled experimental trial. Animals Twelve dogs weighing 15.5 ± 1.7 kg (mean ± SD) and aged 2.5 ± 0.6 years. Methods All dogs underwent a baseline ophthalmic examination and subjective pain score. Anesthesia consisted of acepromazine (0.1 mg kg−1, IM), propofol (4–6 mg kg−1, IV), and isoflurane in oxygen. There were three groups each receiving a bolus followed by an infusion (n = 4): saline (0.3 mL kg−1 IV + 0.2 mL kg−1hour−1 IV); morphine (0.15 mg kg−1 IV + 0.1 mg kg−1hour−1 IV); and lidocaine (1.0 mg kg−1 IV + 0.025 mg kg−1minute−1 IV). All treatments began 15 minutes prior to starting of phacoemulsification and lens removal from the right eye. Pain scores were recorded at 0.5, 1, 2, 3, 4, 6, 8, 16, and 24 hours after t = 0 (extubation). Rescue morphine was administered (1.0 mg kg−1 IM) if the subjective pain score ≥9 (maximum = 24), and the dog was excluded from further data analysis. Differences in pain scores and time-to-treatment failure (TTF) were analyzed using the Wilcoxon's rank sum test. Differences in incidence of treatment failure were analyzed using Fisher's exact test. Physiologic data were analyzed using repeated measures anova . Significance was defined as P < 0.05. Results Incidence of treatment failure was 100% in saline-treated dogs and 50% in morphine- or lidocaine-treated dogs. There was no difference in intraocular pressure, aqueous flare, cell count (or protein) between groups in the operated eye at any time following extubation. Conclusion and clinical relevance This pilot study suggests that intraoperative lidocaine may provide analgesic benefits similar to morphine for intraocular surgery in dogs, but more definitive research is needed. This model appears to be appropriate for pain assessment studies as the negative control group demonstrated 100% failure rate.  相似文献   
85.
This study was carried out to compare the post‐thaw cryosurvival rate and the level of apoptosis in vitro produced zona‐free cloned buffalo blastocysts subjected to slow freezing or vitrification in open‐pulled straws (OPS). Zona‐free cloned embryos produced by handmade cloning were divided into two groups and were cryopreserved either by slow freezing or by vitrification in OPS. Cryosurvival of blastocysts was determined by their re‐expansion rate following post‐thaw culture for 22–24 h. The post‐thaw re‐expansion rate was significantly (p < 0.05) higher following vitrification in OPS (71.2 ± 2.3%) compared with that after slow freezing (41.6 ± 4.8%). For examining embryo quality, the level of apoptosis in day 8 frozen‐thawed blastocysts was determined by TUNEL staining. The total cell number was not significantly different among the control non‐cryopreserved cloned embryos (422.6 ± 67.8) and those cryopreserved by slow freezing (376.4 ± 29.3) or vitrification in OPS (422.8 ± 36.2). However, the apoptotic index, which was similar for embryos subjected to slow freezing (14.8 ± 2.0) or OPS vitrification (13.3 ± 1.8), was significantly (p < 0.05) higher than that for the control non‐cryopreserved cloned embryos (3.4 ± 0.6). In conclusion, the results of this study demonstrate that vitrification in OPS is better than slow freezing for the cryopreservation of zona‐free cloned buffalo blastocysts because it offers a much higher cryosurvival rate.  相似文献   
86.
A thirteen year old neutered female Domestic Shorthair cat with oral squamous cell carcinoma was noted to have a cranial mediastinal mass on survey thoracic radiographs. Fluoroscopic aspiration was performed and cystic fluid was obtained which was clear colorless, and devoid of cells, with a specific gravity of 1.005 and protein <2.5 mg/dl. On postmortem examination, a unilocular cyst was identified originating from the external lateral surface of the cranial mediastinum. Histologically, the cyst lining was nonciliated and resembled mesothelium. These findings differentiate this cyst from previously reported branchial cysts in cats where the cysts were multiloculated, the cyst fluid was mucinous and cellular, and the cysts were lined by ciliated columnar epithelial cells.  相似文献   
87.
Hyperthyroidism associated with thyroid adenoma was diagnosed in a dog. Typical clinical signs of hyperthyroidism were resolved with surgical excision of the adenoma. Hyperthyroidism in dogs usually is associated with thyroid carcinoma, which has a poor prognosis. This case emphasizes the importance of obtaining a histologic diagnosis of thyroid tumors in hyperthyroid dogs before giving a prognosis.  相似文献   
88.
89.
OBJECTIVE: To compare an ELISA measuring serum allergen-specific IgE with intradermal skin testing in canine atopic dermatitis. PROCEDURE: Eighty-four dogs with the clinical diagnosis of atopic dermatitis underwent intradermal skin testing and serum testing for allergen-specific IgE. Tests were performed in a blinded fashion. Positive reactions were compared and the sensitivity and specificity of the serum test (using intradermal skin test as the standard) were determined overall and for individual allergen groups (grass pollens, weed pollens, tree pollens, house dust mites and fleas). RESULTS: The sensitivity of the ELISA overall was 90.4%. Evaluating the individual allergen groups, the sensitivity for dust mite hypersensitivity was 95.1%, for fleas 85.4%, for tree pollens 84.3%, for grass pollens 95.1% and for weed pollens 96.4%. The specificity was 91.6% overall, for dust mites 96.3%, for fleas 92.7%, for tree pollens 95.2%, for grass pollens 94% and for weed pollens 80.7%. CONCLUSION: The evaluated ELISA seemed reliable for the diagnosis of atopy in practice and can be recommended as a screening test prior to intradermal skin testing or for use in dogs when immunotherapy is not a therapeutic option.  相似文献   
90.
The purpose of this study was to identify oxidative damage to renal allografts during graft rejection by evaluating changes in oxidative markers and plasma lactate levels in feline renal allotransplant recipients. Heterotopic renal allotransplantations were performed between 8 adult feline cross-matched donors. Following 14 d of immunosuppression, the drugs were discontinued to allow allograft rejection. Baseline and serial postoperative evaluations of serum creatinine, plasma lactate, plasma thiobarbituate reactive substances (TBARS), plasma creatol, urine creatol, and renal sonographic cross-sectional area were performed. When sonographic evaluation revealed the absence of blood flow to the allograft, the rejected kidney was nephrectomized and evaluated histopathologically. Allograft rejection occurred in all cats by day 26. A significant elevation in body temperature occurred during the rejection period. No significant change was observed between any of the time periods for plasma TBARS, creatol, or urine creatol. There was a significant decrease in plasma lactate levels throughout the study. Markers of oxidative stress from venous blood did not reflect renal allograft rejection in cats with a normally functioning native kidney. Renal allograft rejection may be associated with significant increases in body temperature and warrants further investigation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号