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   581篇
  免费   61篇
  国内免费   5篇
林业   2篇
农学   5篇
  2篇
综合类   128篇
农作物   17篇
水产渔业   4篇
畜牧兽医   378篇
园艺   110篇
植物保护   1篇
  2023年   17篇
  2022年   5篇
  2021年   26篇
  2020年   21篇
  2019年   40篇
  2018年   35篇
  2017年   38篇
  2016年   37篇
  2015年   43篇
  2014年   41篇
  2013年   38篇
  2012年   25篇
  2011年   32篇
  2010年   22篇
  2009年   20篇
  2008年   21篇
  2007年   22篇
  2006年   18篇
  2005年   18篇
  2004年   16篇
  2003年   7篇
  2002年   20篇
  2001年   14篇
  2000年   10篇
  1999年   8篇
  1998年   8篇
  1997年   3篇
  1996年   9篇
  1995年   4篇
  1994年   2篇
  1993年   6篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1989年   3篇
  1988年   3篇
  1986年   1篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1973年   1篇
排序方式: 共有647条查询结果,搜索用时 187 毫秒
41.
MDM2和p53在大肠癌组织中的表达及其意义   总被引:1,自引:0,他引:1  
目的:探讨抑癌基因mdm2、p53在大肠癌组织中表达情况及与临床病理之间的关系。方法:采用免疫组化SABC法检测大肠癌79例,大肠腺瘤样息肉34例,正常大肠粘膜组织15例中MDM2、p53的表达。结果:MDM2在正常大肠组织、大肠腺瘤、大肠癌中表达阳性率分别为6.67%(1/15)、41.18%(14/34)、63.29%(50/79);p53阳性率分别为0、35.29%(12/34)、67.09%(53/79)。MDM2、p53在正常组织、大肠腺瘤、大肠癌组织中表达率逐渐增加(P〈0.01),两者与DukesC期、D期及远处转移相关,与年龄、性别及组织细胞分化程度无关。MDM2与p53表达之间呈正相关。结论:MDM2、p53高表达与大肠癌的发生、发展和预后相关。  相似文献   
42.
利用细胞电泳技术对低分化鼻咽癌细胞系(CNE-2Z)及其21个单克隆细胞株进行检测。CNE-2Z系平均细胞电泳率为1.43±0.35,21个单克隆平均细胞电泳率高低不一,从0.87±0.15到1.72±0.15,说明作为群体细胞系的CNE-2Z在细胞电泳方面具有明显异质性.同时,检测结果初步提供了21个单克隆株的纯度和转移能力的线索.  相似文献   
43.
5-Lipoxygenase (5-LO) is overexpressed in human prostate carcinomas (PCs), and its inhibition decreases proliferation and induces apoptosis in prostate cancer cell lines. We hypothesized that 5-LO would be overexpressed in canine PC compared with benign prostate tissue and may be important in the pathogenesis of the disease. Immunoblot analysis of canine PC and benign prostatic hyperplasia (BPH) tissues demonstrated 5-LO expression in both. 5-LO immunohistochemical staining was not significantly different within the stromal or epithelial components of canine primary PC, BPH or suppurative prostatitis, suggesting that differential expression of this enzyme does not occur in these conditions. The percentage of tumour cells expressing 5-LO was significantly lower in metastatic PC lesions compared with primary PC (P < 0.0001). This decreased expression may indicate down-regulation or altered expression of the enzyme with progression of canine PC to a metastatic phenotype.  相似文献   
44.
The goal of this study was to determine the efficacy and tolerability of gemcitabine in dogs diagnosed with hepatocellular carcinoma (HCC). Eighteen dogs were examined retrospectively (4 massive HCC, 10 nodular HCC and 4 diffuse HCC). All dogs received gemcitabine at 350-400 mg m(-2) weekly for 5 weeks. Toxicity was graded using VCOG-CTCAE guidelines and response was monitored with serial abdominal ultrasounds. Fifteen dogs completed all five cycles. Toxicity was minimal and consisted of grade I/II vomiting, anorexia and diarrhoea and two episodes of grade III neutropenia. Median survival time for all dogs was 983 days. Median progression free interval was 971 days. Based on the results of this study, surgery remains the best treatment for HCC, despite incomplete resection. There was no improvement in the survival of those diagnosed with nonresectable HCC treated with gemcitabine chemotherapy.  相似文献   
45.
Understanding the inherent radiosensitivity and repair capacity of canine transitional cell carcinoma (TCC) can aid in optimizing radiation protocols to treat this disease. The objective of this study was to evaluate the parameters surviving fraction at 2 Gy (SF(2) ), α/β ratio and capacity for sublethal damage repair (SLDR) in response to radiation. Dose-response and split-dose studies were performed using the clonogenic assay. The mean SF(2) for three established TCC cell lines was high at 0.61. All the three cell lines exhibited a low to moderate α/β ratio, with the mean being 3.27. Two cell lines exhibited statistically increased survival at 4 and 24 h in the dose-response assay. Overall, our results indicate that the cell lines are moderately radioresistant, have a high repair capacity and behave similarly to a late-responding normal tissue. These findings indicate that the radiation protocols utilizing higher doses with less fractionation may be more effective for treating TCC.  相似文献   
46.
目的:探讨HSP27、p14^ARF和caspase-3蛋白在大肠癌中的表达及其与大肠癌I临床病理特征的关系。方法:利用sP法检测大肠癌48例和大肠腺瘤10例以及正常大肠黏膜组织15例中HSP27、p14^ARF和caspase-3蛋白的表达。结果:大肠癌组织中HSP27、p14^ARF和caspase-3蛋白阳性表达率分别为79.2%、58.4%和66.7%,大肠腺瘤组织中分别为40.0%、70.0%和100.0%,正常大肠黏膜组织中分别为33.3%、80.0%和93.3%。p14^ARF和caspase-3蛋白的表达在高、中分化癌组的表达率分别为64.1%、74.4%,明显高于低分化组22.2%、33.3%(Pd0.05)。结论:HSP27、p14^ARF和caspase-3与大肠癌的发生有关,可作为大肠癌临床评价肿瘤生物学行为的指标。  相似文献   
47.
本试验利用显微注射技术,制备鼻咽癌来源LMP1基因(N-LMP1)的转基因小鼠。共获得15只首建鼠,经小鼠尾部组织DNA分析,PCR法证明其中两只小鼠有N-LMP1基因扩增带,Southern杂交显示PCR阳性小鼠有特异的杂交信号,整合率为13.3%,N-LMP1转基因小鼠的建立为研究N-LMP1转基因小鼠的建立为研究N-LMP1在鼻咽癌变过程中的作用机制奠定了基础。  相似文献   
48.
OBJECTIVE: To describe a novel technique for blepharoplasty to cover a tissue defect involving >/=50% of the lower eyelid. STUDY DESIGN: Prospective clinical study. ANIMALS: Five cats with lower eyelid squamous cell carcinoma (SCC). METHODS: En bloc resection of SCC by removing >/=50% of the lower lid with either the medial or lateral canthus was performed without other adjunctive treatment for SCC. The lid defect was reconstructed with a transposition skin flap derived from the frontal (medial defect) or temporal (lateral defect) region. The third eyelid was advanced laterally without dissection from its insertion; its outer conjunctival layer was removed, and the skin flap was sutured with single interrupted sutures dorsally over the nictitating membrane, ventrally to the cutaneous edge of the surgical wound and medially or laterally (depending on the canthus removed) to the skin of the remaining lower lid. RESULTS: Satisfactory cosmetic and functional results were achieved and the Schirmer tear tests were normal. In 2 cats, the skin flap needed monthly hair trimming to avoid corneal lesions. CONCLUSIONS: After en bloc resection of SCC involving >/=50% of the lower eyelid, reconstruction can be achieved by relocation of the third eyelid and use of a cutaneous transposition flap sutured to the scarified external surface of the third eyelid. Eyelid apposition and lacrimal function were preserved. CLINICAL RELEVANCE: Blepharoplasty using a cutaneous transposition flap sutured to the scarified surface of a relocated third eyelid should be considered for reconstruction of lower eyelid defects with >/=50% tissue loss of the lid margin.  相似文献   
49.
Abstract— Multiple squamous cell carcinomas in situ were diagnosed in five aged cats. Despite clinical courses ranging from 18 to 30 months, there was no clinical or histologic evidence of breachment of the basement membrane. The condition closely resembles Bowen's disease in humans.
Résumé— Des épithéliomas spinocellulaires multiples in situ ont été diagnostiqués chez 5 chats. Maigré une anclenneté clinique de 18 à 30 mois, il n'y avait pas de signes cliniques ou histologiques d'atteinte de la membrane basale. Cette affection resemble á la maladie de Bowen chez l'homme.
Zusammenfassung— Bei fünf alten Katzen wurden multiple plattenepithelkarzinome in situ diagnostiziert. Trotz der klinischen Krankheitverläufe von 18 bis 30 Monaten konnte weder klinisch noch histologisch ein Durchbrechen der Basalmembran nachgewiesen werden. Dieses Bild ähnelt sehr dem Bowens Krankheit des Menschen.
Resumen  En cinco gatos se diagnosticaron carcinomas multiples de células escamosas in situ. A pesar del curso clínico de 18–30 meses no se observó evidencia clinica, o histológica de infiltración a traves de la membrana basal. La condición es muy semejante a la enfermedad de Bowen en medicina humana.  相似文献   
50.
[目的]研究山核桃果皮提取物抗肿瘤活性。[方法]采用提取及萃取过程制备山核桃果皮提取物分离化合物,选取人肝癌SMMC-7721细胞及人宫颈癌Hela细胞为模型,测定山核桃果皮提取物对肿瘤细胞的抑制作用。[结果]从山核桃果皮所提取出的化合物具有一定的体外增殖抑制作用。[结论]山核桃果皮提取物是一种安全有效的抗肿瘤活性物质。  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