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   431篇
  免费   37篇
  国内免费   21篇
耳鼻咽喉   1篇
儿科学   6篇
妇产科学   4篇
基础医学   56篇
口腔科学   5篇
临床医学   27篇
内科学   132篇
皮肤病学   13篇
神经病学   7篇
特种医学   3篇
外科学   23篇
综合类   65篇
预防医学   39篇
药学   64篇
中国医学   29篇
肿瘤学   15篇
  2023年   7篇
  2022年   7篇
  2021年   10篇
  2020年   11篇
  2019年   18篇
  2018年   15篇
  2017年   10篇
  2016年   12篇
  2015年   17篇
  2014年   34篇
  2013年   34篇
  2012年   34篇
  2011年   29篇
  2010年   23篇
  2009年   23篇
  2008年   21篇
  2007年   33篇
  2006年   19篇
  2005年   12篇
  2004年   16篇
  2003年   7篇
  2002年   8篇
  2001年   5篇
  2000年   8篇
  1999年   3篇
  1998年   2篇
  1996年   6篇
  1995年   6篇
  1994年   1篇
  1993年   3篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1987年   5篇
  1986年   3篇
  1985年   3篇
  1984年   8篇
  1983年   3篇
  1982年   4篇
  1981年   3篇
  1980年   4篇
  1979年   4篇
  1978年   2篇
  1977年   6篇
  1976年   1篇
  1974年   2篇
  1972年   1篇
排序方式: 共有489条查询结果,搜索用时 15 毫秒
1.
目的: 研究川芎嗪(Ligustrazine)逆转脂肪细胞介导的卵巢癌奥沙利铂耐药的作用,以及对肿瘤细胞中耐药相关蛋白ABCB1、ABCC1和ABCG2表达的影响。方法: MTS法研究川芎嗪逆转脂肪细胞介导的卵巢癌奥沙利铂耐药的IC50值和逆转耐药系数;流式细胞实验研究川芎嗪对脂肪细胞介导的耐药卵巢癌细胞的凋亡水平的影响;划痕实验研究川芎嗪对脂肪细胞介导的耐药卵巢癌细胞的迁移能力的影响;Western Blot研究川芎嗪对肿瘤细胞中耐药相关蛋白ABCG1、ABCC1和ABCG2表达水平。结果: 川芎嗪能够逆转脂肪细胞介导的卵巢癌奥沙利铂耐药,其逆转耐药系数为2.8;川芎嗪能够增加脂肪细胞和肿瘤细胞共培养体系下肿瘤细胞的凋亡;川芎嗪能够抑制脂肪细胞和肿瘤细胞共培养体系下肿瘤细胞的迁移;川芎嗪能够减少肿瘤细胞中耐药相关蛋白ABCB1、ABCC1和ABCG2的表达。结论: 川芎嗪能够逆转脂肪细胞介导的卵巢癌奥沙利铂耐药的作用且其机制与减少耐药相关蛋白ABCB1、ABCC1和ABCG2的表达有关。  相似文献   
2.
目的 探究脉冲式关节机械加载对高脂饮食诱导的肥胖小鼠骨丢失的改善作用。方法 将 45只雌性C57BL/6小鼠随机分为普通饮食对照组(Sham组)、高脂饮食模型组(HF组)和高脂加载治疗组(HF+L组),每组 15只。HF组和 HF+L组高脂饮食喂养 4周后,HF+L组进行 4周的机械加载治疗(加载条件为 1 N,10 Hz,3 min/d,每周连续加载 5 d)。治疗结束后测量 3组小鼠体质量指数(BMI)、全身体脂含量和双侧股骨的骨密度。使用 HE染色和MacNeal’s染色分析观察股骨的组织病理改变,使用 Western blot检测成骨生成相关蛋白[碱性磷酸酶(ALP)、Runt相关转录因子 2(RUNX2)]和脂肪生成相关蛋白[过氧化物酶体增殖物激活受体 γ(PPARγ)、CCAAT/增强子结合蛋白 α(C/EBPα)]的表达。结果 与 Sham组相比,HF组小鼠的体脂含量和 BMI升高,骨密度变化率和骨量变化率显著下降,骨小梁面积明显减少,骨髓脂肪细胞增多。机械加载治疗后,HF+L组的骨密度、骨小梁面积比 HF组明显升高,脂肪细胞的数目和面积比 HF 组显著降低(P<0.05)。Western blot 分析结果表明,HF+L 组与 HF 组相比,ALP 和RUNX2的表达显著升高,C/EBPα和 PPARγ的表达明显降低(均P<0.05)。结论 机械加载能够有效缓解由肥胖引起的低骨密度和低骨量,其治疗作用可能通过促进成骨分化和抑制脂肪生成来改善骨丢失。  相似文献   
3.
目的探讨CXC趋化因子配体14(CXCL14)对高糖暴露环境中脂肪细胞焦亡的影响。方法利用“鸡尾酒法”诱导3T3-L1细胞分化为成熟脂肪细胞,用5.5 mmol/L低糖(NG)或25 mmol/L高糖(HG)葡萄糖培养基培养脂肪细胞24 h;HG环境下用不同浓度CXCL14处理3T3-L1细胞不同时间。Western blot检测消化道皮肤素(GSDMD)、核苷酸结合寡聚化结构样受体蛋白3(NLRP3)、天冬氨酸蛋白水解酶-1(Caspase-1)蛋白、白细胞介素-6(IL-6)蛋白表达水平。实时荧光定量PCR检测GSDMD、NLRP3、白细胞介素-1β(IL-1β) mRNA转录水平。LDH测定试剂盒检测脂肪细胞上清液中乳酸脱氢酶(LDH)活力;Annexin V-FITC荧光检测细胞死亡情况;CCK-8法检测各组细胞增殖活力。结果高糖环境下脂肪细胞焦亡发生率升高,CXCL14处理可提高脂肪细胞增殖活力,但脂肪细胞焦亡相关指标却受到CXCL14浓度梯度的不同影响。50 nmol/L CXCL14处理可降低高糖环境下脂肪细胞GSDMD、NLRP3、IL-1β mRNA以及NLRP3蛋白的表达,下调脂肪细胞LDH活力,减少Annexin V-FITC荧光染色细胞死亡率,但25、100、200 nmol/L CXCL14对其焦亡的指标却呈反向趋势。并且50 nmol/L CXCL14干预后脂肪细胞NLRP3、Caspase-1蛋白随干预时间的延长呈先下降再上升趋势。结论CXCL14对高糖环境中脂肪细胞焦亡的影响与其浓度存在相关性。  相似文献   
4.
目的:建立急性寒冷刺激诱导小鼠皮下米黄色脂肪细胞形成的方法。方法:连续3天每天4 h预冷刺激使小鼠适应寒冷环境,然后持续24 h进行急性寒冷刺激,诱导小鼠皮下脂肪中米黄色脂肪细胞形成。采用免疫组化检测皮下脂肪中Ucp1阳性细胞,荧光定量PCR检测米黄色脂肪细胞标志性基因Ucp1、Prdm16、Pgc1α、Cidea的转录,Western blot检测米黄色脂肪细胞标志性蛋白Prdm16和Ucp1的表达。结果:急性寒冷刺激后小鼠皮下脂肪中Ucp1阳性细胞数量明显增加,Ucp1、Prdm16、Pgc1α、Cidea转录明显上调,Prdm16、Ucp1蛋白表达明显升高。结论:本研究建立的急性寒冷刺激诱导小鼠皮下米黄色脂肪细胞形成的方法可靠,可用于米黄色脂肪细胞形成调控机制的研究。  相似文献   
5.
6.
背景:目前用于整容的吸脂术发展很快,但为了脂肪干细胞应用而进行的综合吸脂术研究和比较尚未见报道。 目的:对比目前各种类型脂肪抽取技术的特点以及对基质血管层、脂肪细胞、脂肪干细胞的数量和存活率等指标的影响,评价出细胞活性高、适合进行脂肪干细胞制备、储存及临床科学研究的吸脂技术。 方法:作者分别采用检索关键词“adipose-derived stem cel s,ADSCs, liposuction,SAL,UAL,PAL,WAL”和“脂肪干细胞、脂肪抽取术、负压吸脂术、超声辅助吸脂术、震动辅助吸脂术、水动力辅助吸脂术”检索了PubMed数据库、中国知网全文期刊数据库和美国NIH 临床试验数据库,排除与研究目的无关和内容重复者,保留50篇文献进行进一步分析。 结果与结论:目前可应用于脂肪间充质干细胞采集的现代吸脂技术主要有负压吸脂、超声辅助吸脂、震动辅助吸脂、水动力辅助吸脂。其中负压吸脂、超声辅助吸脂技术、水动力辅助吸脂技术3类技术采集的脂肪混合物中可以分离出脂肪干细胞且具有较高的活性,可以用作自体细胞辅助移植技术和再生疗法。这4类技术虽然各有特点,有必要进一步研究这些吸脂技术获得的脂肪干细胞的活性、遗传性状稳定性、分化能力等系统性对比数据,为未来的再生医学工程提供更准确完善的支持。  相似文献   
7.
Nutritional factors such as casein hydrolysates and long chain polyunsaturated fatty acids have been proposed to exert beneficial metabolic effects. We aimed to investigate how a casein hydrolysate (eCH) and long chain polyunsaturated fatty acids could affect human primary adipocyte function in vitro. Incubation conditions with the different nutritional factors were validated by assessing cell vitality with lactate dehydrogenase (LDH) release and neutral red incorporation. Intracellular triglyceride content was assessed with Oil Red O staining. The effect of eCH, a non-peptidic amino acid mixture (AA), and long-chain polyunsaturated fatty acids (LC-PUFAs) on adiponectin and leptin secretion was determined by enzyme-linked immunosorbent assay (ELISA). Intracellular adiponectin expression and nuclear factor-κB (NF-κB) activation were analyzed by Western blot, while monocyte chemoattractant protein-1 (MCP-1) release was explored by ELISA. The eCH concentration dependently increased adiponectin secretion in human primary adipocytes through its intrinsic peptide bioactivity, since the non-peptidic mixture, AA, could not mimic eCH’s effects on adiponectin secretion. Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and DHA combined with arachidonic acid (ARA) upregulated adiponectin secretion. However, only DHA and DHA/ARA exerted a potentanti-inflammatory effect reflected by prevention of tumor necrosis factor-α (TNF-α) induced NF-κB activation and MCP-1 secretion in human adipocytes. eCH and DHA alone or in combination with ARA, may hold the key for nutritional programming through their anti-inflammatory action to prevent diseases with low-grade chronic inflammation such as obesity or diabetes.  相似文献   
8.

Aim:

Wogonin (5,7-dihydroxy-8-methoxyflavone), a major bioactive compound of the flavonoid family, is commonly extracted from the traditional Chinese medicine Scutellaria baicalensis and possesses antioxidant and anti-inflammatory activities and is assumed to have anti-diabetes function. Indeed, a current study has shown that it can possibly treat metabolic disorders such as those found in db/db mice. However, the underlying molecular mechanism remains largely unclear. The aim of this study was to investigate the impact of wogonin on osteopontin (OPN) expression in adipose tissue from type 1 diabetic mice and in 3T3-L1 adipocytes.

Methods:

Type 1 diabetes was induced by streptozotocin (STZ) injection. 3T3-L1 preadipocytes were converted to 3T3-L1 adipocytes through treatment with insulin, dexamethasone, and 3-isobutyl-1-methylxanthine (IBMX). Western blot analysis and RT-PCR were performed to detect protein expression and mRNA levels, respectively.

Results:

Wogonin treatment suppressed the increase in serum OPN levels and reduced OPN expression in adipose tissue from STZ-induced type 1 diabetic mice. Administration of wogonin enhanced PPARα expression and activity. Silencing of PPARα diminished the inhibitory effects of wogonin on OPN expression in 3T3-L1 adipocytes. Furthermore, the levels of c-Fos and phosphorylated c-Jun were reduced in wogonin-treated adipose tissue and 3T3-L1 adipocytes. In addition, wogonin treatment dramatically mitigated p38 MAPK phosphorylation. Pharmacological inhibition of p38 MAPK by its specific inhibitor SB203580 increased PPARα activity and decreased OPN expression.

Conclusion:

Our results suggest that wogonin downregulated OPN expression in adipocytes through the inhibition of p38 MAPK and the sequential activation of the PPARα pathway. Given the adverse effects of high OPN levels on metabolism, our results provide evidence for the potential administration of wogonin as a treatment for diabetes.  相似文献   
9.
Administration of streptozotocin (STZ) and nicotinamide (NA) to adult rats allows for the induction of mild diabetes. However, this experimental model has not been fully characterized. This study was undertaken to determine the metabolic and secretory activity of adipose tissue in rats with STZ‐NA‐induced diabetes. Experiments were performed using epididymal adipocytes isolated from control and mildly diabetic rats. Lipogenesis, glucose transport as well as glucose and alanine oxidation, lipolysis, anti‐lipolysis, cAMP levels and adipokine secretion were compared in cells isolated from the control and diabetic rats. Lipogenesis, glucose transport and oxidation were diminished in the adipocytes of diabetic rats compared with the fat cells of control animals. However, alanine oxidation appeared to be similar in the cells of non‐diabetic and diabetic animals. Lipolytic response to low epinephrine concentrations was slightly increased in the adipocytes of diabetic rats; however, at higher concentrations of the hormone, lipolysis was similar in both groups of cells. The epinephrine‐induced rise in cAMP levels was higher in the adipocytes of STZ‐NA‐induced diabetic rats, even in the presence of insulin. Lipolysis stimulated by dibutyryl‐cAMP did not significantly differ, whereas anti‐lipolytic effects of insulin were mildly decreased in the cells of diabetic rats. Secretion of adiponectin and leptin was substantially diminished in the adipocytes of diabetic rats compared with the cells of control animals. Our studies demonstrated that the balance between lipogenesis and lipolysis in the adipose tissue of rats with mild diabetes induced by STZ and NA is slightly shifted towards reduced lipid accumulation. Simultaneously, adiponectin and leptin secretion is significantly impaired.  相似文献   
10.
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