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   92篇
  免费   13篇
  国内免费   17篇
农学   2篇
综合类   20篇
农作物   1篇
水产渔业   34篇
畜牧兽医   62篇
园艺   3篇
  2024年   1篇
  2022年   4篇
  2021年   3篇
  2020年   7篇
  2019年   2篇
  2018年   3篇
  2017年   5篇
  2016年   7篇
  2015年   4篇
  2014年   2篇
  2013年   3篇
  2012年   3篇
  2011年   5篇
  2010年   2篇
  2009年   7篇
  2008年   4篇
  2007年   4篇
  2006年   3篇
  2005年   7篇
  2004年   2篇
  2003年   5篇
  2002年   6篇
  2001年   8篇
  2000年   4篇
  1999年   1篇
  1996年   3篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   5篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1985年   3篇
  1956年   1篇
排序方式: 共有122条查询结果,搜索用时 15 毫秒
81.
Cell cannibalism refers to the engulfment of cells by nonprofessional phagocytic cells. Studies in human medicine have demonstrated a relationship between the presence of cell cannibalism by neoplastic cells and a poor outcome, and have shown a positive correlation with the presence of metastasis at the time of diagnosis. The biologic significance of cell cannibalism is unknown, but it is proposed that it may represent a novel mechanism of tumor immune evasion as a survival strategy in cases of unfavorable microenvironmental conditions. This report describes clinical and morphologic features of 3 cases of dogs with malignant neoplasia in which the presence of cellular cannibalism was observed in cytologic and histologic specimens. In the 1st case, a dog with a primary tonsillar squamous cell carcinoma with metastasis to retropharyngeal lymph nodes had neoplastic epithelial cells engulfing neutrophils noted in cytologic examination of the lymph nodes. In the 2nd case, neoplastic epithelial cells were seen engulfing each other in fine‐needle aspirates from a primary mammary carcinoma with lung metastasis. In the 3rd case, poorly differentiated neoplastic mast cells from a recurrent, metastatic grade III mast cell tumor were observed cannibalizing eosinophils. A brief review of the literature describing known cell‐into‐cell relationships and the possible biologic significance and mechanisms involved in this phenomenon is provided. The relationship between cell cannibalism and distant metastasis should be explored in further studies, as it may prove to be a criterion of malignancy, as it is proposed in human medicine.  相似文献   
82.
We hypothesized that neutrophil function in tumour‐bearing dogs is negatively impacted by chemotherapy. Flow cytometric techniques were used to assess neutrophil oxidative burst and phagocytic activities at baseline, 7 and 21 days after induction chemotherapy in 20 dogs with lymphoma. Dogs had a lower percentage of neutrophils exhibiting oxidative burst activity after stimulation with Escherichia coli (day 7; P = 0.009) and phorbol 12‐myristate 13‐acetate (PMA) (days 7 and 21; P = 0.0003 and P = 0.01, respectively), compared with healthy controls. From day 0 to 7, the percentage of neutrophils exhibiting oxidative burst activity decreased after stimulation with E. coli (P = 0.016) and PMA (P = 0.0006). Induction chemotherapy suppresses the percentage of neutrophils capable of oxidative burst in dogs with lymphoma, with improvement in phagocytic activity over time (P = 0.03). The impact of neutrophil dysfunction on incidence and severity of sepsis in dogs receiving chemotherapy should be investigated.  相似文献   
83.
Livestock blood discarded during slaughtering has potentially valuable components such as plasma proteins and haemoglobin. Plasma is used as a feed additive following processing via different methods, including spray drying, whereas blood cells have been underutilized. In this study, we developed haemoglobin hydrolysate (HH) and iron-enriched residue (IER) from porcine blood cells and investigated whether their oral administration regulates the immune system and gut microbiota in growing rats. Twenty-one Sprague-Dawley male rats (n = 7) were used during a 4-week trial and were fed a control, HH or IER diet. The ratio of beneficial bacteria such as Lactobacillus and Akkermansia strains increased in rats fed HH or IER diets. Moreover, compared with the control group, the IER group had an elevated ratio of Lactobacillus to Enterobacteria, which is regarded as an index of beneficial aspect in the gut. Phagocytosis of peripheral blood leucocytes was higher in the HH and IER groups than in the control group. The level of plasma immunoglobulin G increased to approximately 72.7 mg/ml and 152.0 mg/ml in the HH and IER groups, respectively, which was significantly (p < 0.05) higher than that in the control group. These results confirm that HH and IER developed in this study may be a potential additive for animal feeds.  相似文献   
84.
亮氨酸脑啡肽对栉孔扇贝血细胞吞噬作用的影响   总被引:1,自引:0,他引:1  
向栉孔扇贝(Chlamys farreri)血淋巴中加入不同浓度的亮氨酸脑啡肽(leucine-enkephalin,L-ENK),研究其对栉孔扇贝血细胞吞噬杆菌作用的影响.结果表明,血细胞的吞噬能力随L-ENK浓度的升高而增强,L-ENK能增强栉孔扇贝血细胞的吞噬能力,可作为一种较好的免疫刺激剂.  相似文献   
85.
几种重金属对刺参体腔细胞超氧阴离子(O2-)产生的影响   总被引:1,自引:0,他引:1  
测定重金属(Zn2 、Pb2 、Cd2 、Cu2 )对刺参体腔细胞吞噬过程中超氧阴离子(O2-)产生的影响。结果表明:Cu、Zn、Pb、Cd均能抑制刺参体腔细胞吞噬过程中超氧阴离子(O2-)的产生。低浓度重金属离子Zn2 (1、5、10mg.L-1),Pb2 (0.5mg.L-1),Cd2 (0.05mg.L-1)处理刺参体腔细胞能使其吞噬过程活性氧产生增加;高浓度重金属离子Zn2 (50、100、200mg.L-1),Pb2 (1、5、10、50、100mg.L-1),Cd2 (0.5、5、10、50、100mg.L-1)处理能明显地抑制刺参体腔细胞吞噬过程中的超氧阴离子(O2-)的产生,Cu2 在浓度为0.1mg.L-1时就开始对超氧阴离子(O2-)的产生抑制,随着浓度的加大,抑制作用明显。  相似文献   
86.
猪圆环病毒2型感染对猪肺泡巨噬细胞生物学活性的影响   总被引:3,自引:1,他引:2  
将猪圆环病毒2型(PCV2)BF株经口、鼻接种40日龄健康仔猪,在接种后不同时间宰杀,收集猪肺泡巨噬细胞(PAM),同时设立对照。用FITC—Annexin V/PI双染色流式细胞术和琼脂糖凝胶电泳检测PAM凋亡现象,通过EA花环试验测定Fc受体数目,通过吞噬鸡红细胞试验测定吞噬功能,分析PCV2感染对PAM生物学活性的影响。结果显示,在整个试验期内2种方法均没有检测到PAM凋亡,表明PCV2感染不会诱发PAM凋亡。PAM的Fc受体数和吞噬鸡红细胞数的变化规律一致,与对照组相比,两者数量在接种后第3d明显下降,第7d有所回升,之后基本恢复,表明PCV2感染后PAM吞噬和清除病原的功能出现短暂下降。  相似文献   
87.
An eosinophilic dermatosis was diagnosed in a dog with a multifocal distribution of pruritic, pustular and erosive lesions on the trunk. Ectoparasites, fungi and bacteria were not detected in the skin of the dog. At a subsequent admission to the university clinic, bacterial conjunctivitis and superficial pyoderma had developed. At a time when the dog received no medical therapy, evaluation of phagocytosis and chemotactic migration towards a variety of chemotactic factors revealed a general suppression of patient neutrophil responsiveness, as compared to a control dog. Viability of the patient's neutrophils was normal. It was proposed that deactivation of neutrophil functions occurred following exposure to suppressive factors from mast cells, or as a consequence of surface receptor down-regulation due to prolonged cell activation by as yet unknown stimulants. The observed susceptibility to infections in the dog suffering from a primary, sterile eosinophilic dermatosis may be related to impaired host defence against opportunistic microorganisms.  相似文献   
88.
扶正方剂“七补散”煎剂灌服10d后,能促进健康小鼠吞噬细胞的吞噬功能,提高体内T淋巴细胞转化率,增加血清中溶血素的含量,对小鼠脾、胸腺的重量及外周血T淋巴细胞百分率的影响则不显著。本实验结果表明,“七补散”具有广泛增强机体免疫功能的作用,“扶正”包括增强机体免疫力,“正气”与机体的免疫功能密切相关。  相似文献   
89.
The intracellular behaviour of a Flavobacterium psychrophilum strain, ingested by spleen phagocytes of rainbow trout, Oncorhynchus mykiss , of different ages, was assessed in vivo . Three groups of rainbow trout weighing 1 g (aged 10 weeks), 25 g (aged 20 weeks) and 300 g (aged 15 months), respectively, were injected intraperitoneally with 1 × 106 cfu of a F. psychrophilum strain. It was found that only fry, aged 10 weeks, displayed clinical signs and suffered mortality. Bacteriological colony plating of different organs demonstrated that the spleen and to a lesser extent the kidney of only the fry were affected. The number of colony forming units per gram of spleen tissue increased with time. No bacteria were found in the trout aged 5 months and older. Light microscopical examination and epifluorescence microscopy revealed that the fry spleen phagocytes contained an increasing number of viable intracellular F. psychrophilum bacteria over time. Again, no bacteria were encountered in the phagocytes collected from older fish.  相似文献   
90.
Relationship between ultrastructure and specific functions of macrophages   总被引:1,自引:0,他引:1  
The main function of the macrophages, which is to ingest and degrade any foreign molecules or particles penetrating the organism, appears in the development of the different structures implicated in endocytic activity. The macrophage's high endocytic property first appears in its irregular shape and the large number of extensions of the cell membrane, allowing the rapid capture of extra-cellular material. Adhesion between macrophage cell surface and molecules or particles is greatly enhanced by the presence of varied kinds of receptors: lectin-like receptors which bind specific sugars or highly specific receptors such as Fc and C3b receptors, which increase phagocytosis of opsonized microbes. The microbicidal properties reside in part in the production of superoxide anions which result from the activity of a NAD(P)H oxidase. This enzyme is located in the plasma membrane. Its activity could be demonstrated with a cytochemical method, on the cell surface and along the phagosome membrane. It is, however, very weak in resident macrophages and increases after stimulation or activation. The second kind of bactericidal property corresponds to cationic proteins located in lysosomes. After fusion between lysosomes and phagosomes, they contribute to microbe killing by permeabilizing microbe envelopes. Lysosomes, which contain diverse acid hydrolases and are responsible for the degradation of ingested material, play a crucial role in macrophage endocytic activity. Their number increases in parallel with endocytic activity during macrophage differentiation and is particularly high after ingestion of degradable material. Contrary to polymorphonuclear leukocytes, macrophage is very poor in granules containing peroxidase. The latter, which are rather abundant in monocytes, disappear during macrophage maturation. They do not seem thus to be implicated in macrophage microbicidal activity. Endocytosis is accompanied by rapid and intense exchanges between the different membrane compartments of the cell (plasma membrane, pinosomes or phagosomes, endosomes, lysosomes, Golgi apparatus, etc.). These exchanges seem to occur by transitory fusions between vesicles coming from different compartments, rapidly followed by their recycling to their original compartment. This system of membrane shuttle has been clearly observed after formation of phagosomes or pinosomes in which the internalized plasma membrane is recycled back to the cell surface within a few minutes after their formation. This membrane traffic is especially intense in macrophages, the endocytic activity of which is very high, but it also exists in all cell types.(ABSTRACT TRUNCATED AT 400 WORDS)  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