全文获取类型
收费全文 | 839篇 |
免费 | 81篇 |
国内免费 | 67篇 |
专业分类
林业 | 10篇 |
农学 | 33篇 |
12篇 | |
综合类 | 262篇 |
农作物 | 10篇 |
水产渔业 | 71篇 |
畜牧兽医 | 564篇 |
园艺 | 11篇 |
植物保护 | 14篇 |
出版年
2024年 | 3篇 |
2023年 | 11篇 |
2022年 | 12篇 |
2021年 | 38篇 |
2020年 | 29篇 |
2019年 | 27篇 |
2018年 | 23篇 |
2017年 | 35篇 |
2016年 | 28篇 |
2015年 | 39篇 |
2014年 | 36篇 |
2013年 | 51篇 |
2012年 | 53篇 |
2011年 | 57篇 |
2010年 | 55篇 |
2009年 | 56篇 |
2008年 | 44篇 |
2007年 | 52篇 |
2006年 | 47篇 |
2005年 | 32篇 |
2004年 | 23篇 |
2003年 | 21篇 |
2002年 | 16篇 |
2001年 | 18篇 |
2000年 | 17篇 |
1999年 | 25篇 |
1998年 | 13篇 |
1997年 | 19篇 |
1996年 | 14篇 |
1995年 | 13篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 14篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有987条查询结果,搜索用时 15 毫秒
31.
Diaa Massoud Mashael M. Bin-Meferij Attala F. El-Kott Mona M. Abd El-Maksoud Sally Negm 《Anatomia, histologia, embryologia》2023,52(2):254-261
This study aimed to investigate the major salivary glands in the southern white-breasted hedgehog (Erinaceus concolor) histologically and histochemically. Five adult males were included in this study. The results showed that anatomically the shape of the parotid, submandibular and sublingual glands of the Erinaceus concolor was respectively almost pear, elliptical to pyramidal and oval. Histologically, the parotid gland had serous acini and secretory cells showed negative reaction to alcian blue (AB) (pH = 2.5) and negative response to aldehyde fuchsin (AF), methylene blue (MB) and PAS stains. The submandibular gland was a mixed gland of mucous and serous acini. The mucous acini were strongly positive for PAS, AB, MB and AF. However, serous acini were week for PAS and negative against AB, MB and AF stains. The sublingual gland was purely composed of mucous acini. The mucous acini of the sublingual gland were strongly positives for PAS, AB and MB methods. While their reaction to the AF staining was negative. In conclusion, the histological and histochemical observations of the major salivary glands of the southern white-breasted hedgehog (E. concolor) indicated that these glands shown similarities and some special different histochemical features as compared to other mammalian species. 相似文献
32.
Olivier Taeymans Luc Duchateau Elke Schreurs Martin Kramer Sylvie Daminet Jimmy H. Saunders 《Veterinary radiology & ultrasound》2005,46(2):139-142
The repeatability of ultrasonographic measurements of the canine thyroid gland was evaluated. The variability of three different parameters (the maximal length, width, and height) within observer, between observer and between dogs was assessed based on three different measurements made by each of three observers infive healthy beagle dogs. From the three parameters, the volume of the gland was estimated using a formula of a rotation ellipse. The height and the volume had the lowest intra- and interobserver variability, while measurements of the length had the biggest intra- and interobserver variability. The mean values, with their 90% confidence interval were: height = 0.53cm [0.33-0.73], length = 2.45cm [2.04-2.85], width = 0.62cm [0.46- 0.78], volume = 0.38 cm3 [0.20-0.55]. 相似文献
33.
AIM: To study the effects of intrathymic inoculation of liver specific antigen (LSA) on hepatocyte apoptosis after liver allotransplantation. METHODS: Orthotopic liver transplantation was used in this study. Group Ⅰ: syngenic control (Wistar-to-Wistar); Group Ⅱ: acute rejection (SD-to-Wistar); Group Ⅲ: thymus inoculation of SD rat LSA day 7 before transplantation. The observation of general situation and survival time, hepatocyte apoptosis and LAT expression in liver transplants were used to analyze immune state of animals in different groups. RESULTS: The general situation of group Ⅰ was very well after transplantation. Recipients of groupⅡ lost body weight progressively and all died within day 9 to day 13 post transplantation. As for group Ⅲ, the general situation of recipients was remarkably better than that in group Ⅱ. The positive cells of apoptosis in group Ⅲ detected by TUNEL were not significantly different from that in group Ⅰ, but was significantly lower than that in group Ⅱ. LAT was detected at any time in group Ⅱ with peak expression at day 5 and day 7 post transplantation. In contrast, LAT was not detected in any other groups. CONCLUSION: Intrathymic inoculation of LSA protects hepatocytes from apoptosis after liver allotransplantation. 相似文献
34.
Exons 4 to 8 of the tumour suppressor gene p53 were analysed in 25 skin and 25 mammary tumours of 50 dogs. A 1 bp deletion (ACCAC) was detected in codon 89 in exon 4 in a squamous cell carcinoma. A missense mutation CGCCAC (argininehistidine) was present in codon 162 in exon 5 in a mammary adenocarcinoma. Moreover, a silent mutation occurred in codon 103 (serine) of exon 4 in a mammary adenoma. The somatic nature of the three mutations was demonstrated. 相似文献
35.
36.
GIOVANNA BERTOLINI TOMMASO FURLANELLO DAVIDE DE LORENZI MARCO CALDIN 《Veterinary radiology & ultrasound》2006,47(5):444-448
We conducted a retrospective study in presumed normal dogs to determine the adrenal gland attenuation and volume values. Multidetector computer tomography (MDCT 16) analysis of the gland was carried out in 48 adult dogs without evidence of adrenal gland disease that underwent CT examination for acute spinal injuries. The mean nonenhanced attenuation value +/- SD of the left adrenal gland was 36.0 +/- 5.3 HU (range: 22.0-42.0 HU). The mean nonenhanced attenuation value +/- SD of the right gland was 34.3 +/- 7.0 HU (range: 20.4-48.6HU). The mean enhanced attenuation value +/- SD were: left gland 101.5 +/- 10.6HU (range: 86.8-128.0 HU), and right gland 97.4 +/- 12.4 HU (range: 58.9-123.6 HU). The mean CT volume +/- SD were: left gland was 0.60 cm3 (range: 0.20-0.95; SD 0.17), and right gland (0.55cm3, range: 0.22-1.01; SD 0.19). Attenuation values and volume data were related to age, weight, and gender, using ANOVA. There was no statistically significant difference between the left and right side or in adrenal measurements, because of body weight class effects. The animal effect was the most important source of variation for all adrenal measurements. Based on our study, CT is an effective method for assessing adrenal characteristics in the dog. Normative CT data are provided to allow estimation of normal adrenal gland size and volume. 相似文献
37.
38.
Ultrasonographic images were acquired of the mammary glands of 40 bitches with physiologically lactating (n = 20) or inflamed glands (n = 20). Echogenicity, structure, homogeneity, thickness, and distinguishability of each tissue layer were assessed. Additionally, overall echogenicity was noted. In the normal lactating gland, different tissues could be differentiated easily. The parenchyma was, without exception, separated from adjacent tissues and was visible as medium echogenic tissue with a coarse-grained structure. The tissue always had some echogenic lines and anechoic areas and was slightly heterogeneous. The loss of distinct layering of the tissue was characteristic of an inflamed mammary gland and inflamed regions had reduced echogenicity. Additionally in five bitches with mastitis, the ultrasound examination was repeated five times for documentation of the progress of the illness and associated changes, supplemented with a color Doppler sonogram to assess changes in blood vessel density. Information from the examinations carried out via B-mode did not allow treatment success to be predicted. Two bitches with reduced blood vessel density centrally had a poor outcome whereas three bitches with increased blood vessel density had a good outcome. Thus, Doppler sonography might be a useful tool to obtain information of the prognosis in acute canine mastitis. 相似文献
39.
Andrew J. Brown MA VetMB DACVECC MRCVS Amy J. Alwood DVM Steven G. Cole DVM DACVECC 《Journal of Veterinary Emergency and Critical Care》2007,17(2):164-169
Objective: To describe a case of atrioventricular block and syncope secondary to systemic hypertension in a dog with malignant pheochromocytoma. Case Summary: A 13‐year‐old spayed female mixed‐breed dog presented following an acute onset of collapse. The dog was hypertensive and had paradoxical high‐grade second‐degree atrioventricular block with concurrent syncope. Initial emergent therapy included a nitroprusside infusion for the systemic hypertension and vagolytic therapy for the bradyarrhythmia. A left adrenal mass was seen on abdominal ultrasound and was further characterized by MRI. Following medical stabilization with phenoxybenzamine and propantheline, a left adrenalectomy was performed. Histological diagnosis was consistent with a malignant pheochromocytoma. Following tumor removal there has been no further hypertension, atrioventricular block or syncope. Unique information provided: This is the first documented case of a malignant pheochromocytoma presenting as syncope secondary to hypertension induced atrioventricular block. 相似文献
40.
M. Yavuz Gulbahar Tolga Guvenc Murat Yarim Yonca B. Kabak Yuksel Sozgen 《Journal of veterinary science (Suw?n-si, Korea)》2007,8(4):423-425
A fibroadenoma was diagnosed in the left udder of a 3-month-old female Chios lamb. No recurrence was observed after surgery. Grossly, the tumor had a whitish-gray lobular appearance, and the lobules were interlaced with thin septa. Microscopically, the tumor was composed of proliferating fibroepithelial tissue, including differentiated ducts lined by whorls and interlacing bundles of abundant loose fibrovascular stroma. Immunohistochemistry revealed the ductal epithelium to be positive for pancytokeratin (AE1/AE3) and loose fibrovascular stroma was positive for vimentin and basal cells covering the ductal epithelium of alpha-smooth-muscle actin. Immunostaining for the estrogen and progesterone receptors was negative. A diagnosis of mammary fibroadenoma was made based on the histological and immunohistochemical findings. 相似文献