全文获取类型
收费全文 | 1703篇 |
免费 | 155篇 |
国内免费 | 212篇 |
专业分类
林业 | 43篇 |
农学 | 152篇 |
基础科学 | 204篇 |
129篇 | |
综合类 | 467篇 |
农作物 | 116篇 |
水产渔业 | 172篇 |
畜牧兽医 | 540篇 |
园艺 | 56篇 |
植物保护 | 191篇 |
出版年
2024年 | 14篇 |
2023年 | 43篇 |
2022年 | 69篇 |
2021年 | 80篇 |
2020年 | 100篇 |
2019年 | 101篇 |
2018年 | 64篇 |
2017年 | 104篇 |
2016年 | 113篇 |
2015年 | 84篇 |
2014年 | 111篇 |
2013年 | 101篇 |
2012年 | 102篇 |
2011年 | 121篇 |
2010年 | 77篇 |
2009年 | 79篇 |
2008年 | 88篇 |
2007年 | 64篇 |
2006年 | 62篇 |
2005年 | 69篇 |
2004年 | 46篇 |
2003年 | 44篇 |
2002年 | 45篇 |
2001年 | 33篇 |
2000年 | 29篇 |
1999年 | 25篇 |
1998年 | 23篇 |
1997年 | 26篇 |
1996年 | 19篇 |
1995年 | 25篇 |
1994年 | 17篇 |
1993年 | 15篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2070条查询结果,搜索用时 15 毫秒
991.
Kyohei Yasuno Haruka Sakashita Ryosuke Kobayashi Saori Araki Rio Saito Mariko Shirota Junichi Kamiie Kinji Shitora 《Journal of toxicologic pathology》2013,26(2):203-208
Membranous glomerulonephropathy can be experimentally induced in rats, but spontaneous
cases have been rarely reported. In this report, we present a typical case of spontaneous
membranous glomerulonephropathy in a rat. A male Hatano low-avoidance (LAA) strain rat had
a tumor mass on the right auricle, and was sacrificed at 41 weeks of age. Urinary
screening by reagent strips revealed intense proteinuria. Histological tests revealed
frequent presence of irregularly sized eosinophilic hyaline materials on the capillary
wall and in the mesangium of renal glomeruli. Immunofluorescence revealed granular
deposits of IgG, IgM, and C3 in the glomeruli. Subepithelial dense deposits were observed
by electron microscopy accompanied by podocyte foot process effacement and occasional
irregular thickening of the glomerular basement membrane. The rat also developed chronic
lymphocytic pancreatitis, and the tumor mass on the right auricle was diagnosed as a
fibrosarcoma. Screening tests for antibodies against major infectious agents and
antinuclear antibody were negative. Western blot and indirect immunofluorescence analyses
suggested the presence of an autoantibody against the pancreatic component. The
glomerulopathy was considered an early stage of membranous glomerulonephropathy. 相似文献
992.
ZOU Wen-bo SU Jin-zi XU Chang-sheng CAI Wen-qin MA Wen-wen CHEN Xiu-ping WANG Fang-bing 《园艺学报》2013,29(8):1393-1399
AIM:To investigate the protective effect of atorvastatin (ATO) against contrast medium (CM)-induced apoptosis of renal tubular epithelial cells in diabetic rats. METHODS:Streptozocin-induced diabetic Wistar rats were fed for 8 weeks and then randomly divided into 5 groups: diabetes mellitus (DM) group, DM with iopromide (a kind of CM) treatment group (DM+CM group), and groups of DM rats treated with ATO at 5 mg·kg-1·d-1 (ATO1 group), 10 mg·kg-1·d-1 (ATO2 group) and 30 mg·kg-1·d-1 (ATO3 group) before iopromide injection. Healthy Wistar rats served as normal controls (N group). Urine creatinine (UCr) and 24-hour urinary albumin (24 h-UAlb) were determined 24 h after iopromide injection. Serum creatinine (SCr) and blood urea nitrogen (BUN) were detected 48 h after iopromide injection, and then creatinine clearance (CCr) and 24-hour urinary albumin excretion rate (24 h-UAER) were calculated. The rats were sacrificed and both kidneys were removed 48 h after iopromide injection. For the left kidney, the morphology by HE staining, the renal tubular apoptosis by TUNEL and the expression of Bax and Bcl-2 by immunohistochemistry were detected. For the right kidney, the expression of Bax and Bcl-2 was measured by Western blotting. RESULTS:Compared with N and DM groups, the levels of SCr, BUN and 24 h-UAER, as well as the expression of Bax in the renal medulla were higher, the levels of Ccr and Bcl-2 expression in the renal medulla were lower and TUNEL-positive cells were more in DM+CM group. Compared with DM+CM group, ATO attenuated these changes, especially in ATO3 group. CONCLUSION: Iopromide could cause renal tubular apoptosis. Early application of ATO could dose-dependently attenuate the development of contrast-induced acute kidney injury, partly due to suppression of iopromide-induced renal tubular apoptosis. 相似文献
993.
Jeffrey D. Ruth Hock Gan Heng Margaret A. Miller Peter D. Constable 《Veterinary radiology & ultrasound》2013,54(6):659-665
The echogenicity of the renal cortex is an important parameter to consider in dogs that are suspected to have renal dysfunction. Focal increases in echogenicity have been attributed to neoplasia, infection, calcification, fibrosis, gas, and infarction. Anisotropic backscatter has been described as a source of focally increased renal cortical echogenicity in several species. The source of anisotropy appears to be the medullary rays, which are oriented perpendicular to the renal capsule. Spatial compound imaging (SCI) is an ultrasound setting that uses beam steering to acquire and average several overlapping scans of an object from different view angles, creating a compound image that is updated in real time. The impact of insonation angle and SCI on renal cortical echogenicity was evaluated ex vivo in eight kidneys from four dogs. Significant angle‐dependent differences in cortical echogenicity were detected with both microconvex and linear transducers (P < 0.0001). Furthermore, the angle‐dependent echogenicity differences persisted when SCI mode was used. Our finding that echogenicity was increased using a perpendicular insonation angle (90°) relative to the tubules, compared to a parallel insonation angle (0°) should assist in the interpretation of ultrasonographic images of the dog kidney. 相似文献
994.
Reid Tyson Stacy A. Logsdon Stephen R. Werre Gregory B. Daniel 《Veterinary radiology & ultrasound》2013,54(2):127-132
Renal volume estimation is an important parameter for clinical evaluation of kidneys and research applications. A time efficient, repeatable, and accurate method for volume estimation is required. The purpose of this study was to describe the accuracy of ultrasound and computed tomography (CT) for estimating feline renal volume. Standardized ultrasound and CT scans were acquired for kidneys of 12 cadaver cats, in situ. Ultrasound and CT multiplanar reconstructions were used to record renal length measurements that were then used to calculate volume using the prolate ellipsoid formula for volume estimation. In addition, CT studies were reconstructed at 1 mm, 5 mm, and 1 cm, and transferred to a workstation where the renal volume was calculated using the voxel count method (hand drawn regions of interest). The reference standard kidney volume was then determined ex vivo using water displacement with the Archimedes’ principle. Ultrasound measurement of renal length accounted for approximately 87% of the variability in renal volume for the study population. The prolate ellipsoid formula exhibited proportional bias and underestimated renal volume by a median of 18.9%. Computed tomography volume estimates using the voxel count method with hand‐traced regions of interest provided the most accurate results, with increasing accuracy for smaller voxel sizes in grossly normal kidneys (–10.1 to 0.6%). Findings from this study supported the use of CT and the voxel count method for estimating feline renal volume in future clinical and research studies. 相似文献
995.
Aline Herrera Farha Jeana Pereira da Silva Stela Bonadia de Souza Bete Maria Jaqueline Mamprim Bruno Cesar Schimming 《Anatomia, histologia, embryologia》2021,50(3):614-624
The aim of this study was to identify the anatomical structures in the head region of the giant anteater (Myrmecophaga tridactyla) using computed tomography. For this, three giant anteater corpses, adult and female, were used. The tomographic analysis was performed in sequential order in rostrocaudal direction. Subsequently, the heads of these animals were sectioned in cross sections of approximately 1.5 cm each. Tomographic images were compared with anatomical sections. The association between computed tomography and anatomical sections allowed the visualization of anatomical structures found in the nasal, oral, cranial, pharyngeal and ear cavities. An elongated oral cavity delimited by the elongated mandible was observed. The oral cavity was mainly occupied by a thin and elongated tongue formed mainly by the union of the sternoglossal muscles. The nasopharynx and oropharynx extended up to the neck at the level of the fifth cervical vertebra. The findings of this study suggest that the giant anteater has a head with structures morphologically adapted to its feeding habits, such as an elongated skull, tongue, styloid bones and mandible. In addition, based on the results of this study, it is possible to suggest that computed tomography is a pivotal tool for the veterinary routine of wild animals, since it allowed the identification of anatomical structures found in the head of the giant anteater. 相似文献
996.
小麦赤霉病已发展成为危害黄淮南部麦区小麦生产的主要病害,快速提高黄淮南部麦区小麦品种的赤霉病抗性是解决赤霉病问题的重要途径。本研究采用回交和分子标记辅助选择技术,将抗赤霉病主效基因Fhb1和Fhb7导入黄淮南部麦区3个优异小麦品种中。结果发现,在基本保持原有丰产性和品质特性的基础上,3个小麦品种回交后代群体的赤霉病抗性提高了38.38%~52.87%。通过对主要农艺性状和抗病性选择,从以郑麦1860为受体亲本的回交后代群体中,选育出6个与受体亲本产量水平相当、主要品质特性相似、赤霉病抗性显著提高的小麦新品系。在回交过程中采用人工气候室加代技术加快育种进程,每世代平均需要112 d。本研究的育种方法可用于今后黄淮南部麦区小麦品种的赤霉病抗性快速改良。 相似文献
997.
998.
Jiabao Lin Luqi Lin Siyu Chen Lifang Yu Songjie Chen Zhaofei Xia 《Journal of veterinary diagnostic investigation》2021,33(2):288
Fibroblast growth factor 23 (FGF-23) is an independent monitor of the progression of chronic kidney disease (CKD) in human medicine, and FGF-23 may have value as a biomarker in feline CKD. We evaluated the relationship between serum FGF-23 and CKD stages, and the effect of age on FGF-23 in normal cats. We measured FGF-23 and intact parathyroid hormone (iPTH) concentrations by ELISA, with intra- and inter-assay CVs ≤ 15%. The percentage recovery of FGF-23 and iPTH remained stable for up to 7 d in samples stored at −20°C and −80°C. We measured FGF-23 in 304 cats, among which 196 were diagnosed with CKD. The 108 clinically healthy cats were divided into 5 subgroups based on growth stage (0–2 y, 3–6 y, 7–10 y, 11–14 y, ≥ 15 y). No statistical difference was found in FGF-23 among age groups (p = 0.15) or by sex in healthy subjects. Using the International Renal Interest Society guideline, 34 cats were defined as CKD stage 1, 74 stage 2, 51 stage 3, and 37 stage 4. FGF-23 was higher in cats in all CKD stages than in controls. Higher serum phosphorus was observed in stage 3 (p = 0.04) and 4 (p < 0.01) compared to controls. iPTH increased as CKD progressed. Pearson analysis indicated a positive linear relationship between FGF-23 and iPTH (control: r = 0.70, p < 0.01; CKD: r = 0.46, p = 0.02). FGF-23 may be a useful biomarker of feline CKD and may precede hyperphosphatemia in advanced feline CKD. 相似文献
999.
1000.
为了探索微生物菌剂对结球生菜的影响,选用"润雨"微生物菌剂,开展其在张家口坝上地区对结球生菜产量、品质和抗病性的影响试验。结果表明:与传统施肥相比,在结球生菜整个生育期每667 m~2追施4 kg微生物菌剂,植株的株高、株幅和最大叶质量显著增加,一级品产量和一级品率也有明显提高,分别为82 245 kg/hm~2、94.6%;可溶性蛋白、维生素C和可溶性糖含量明显提高;植株抗病性增强,软腐病、霜霉病、菌核病的发生率降低,尤其是软腐病和霜霉病,发病率仅为5.39%、8.54%。综合考虑,推荐在生产上推广使用微生物菌剂,促进作物生长的同时实现农药减施。 相似文献