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   1529篇
  免费   389篇
  国内免费   22篇
  1940篇
  2024年   21篇
  2023年   63篇
  2022年   83篇
  2021年   105篇
  2020年   106篇
  2019年   89篇
  2018年   78篇
  2017年   69篇
  2016年   80篇
  2015年   101篇
  2014年   148篇
  2013年   123篇
  2012年   108篇
  2011年   113篇
  2010年   64篇
  2009年   52篇
  2008年   62篇
  2007年   59篇
  2006年   60篇
  2005年   47篇
  2004年   37篇
  2003年   32篇
  2002年   30篇
  2001年   16篇
  2000年   17篇
  1999年   12篇
  1998年   8篇
  1997年   16篇
  1996年   5篇
  1995年   18篇
  1994年   20篇
  1993年   9篇
  1992年   13篇
  1991年   14篇
  1990年   9篇
  1989年   14篇
  1988年   7篇
  1987年   2篇
  1986年   8篇
  1985年   2篇
  1984年   5篇
  1983年   4篇
  1982年   5篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1976年   1篇
排序方式: 共有1940条查询结果,搜索用时 15 毫秒
51.
Drug resistance is a critical obstacle to effective treatment in patients with chronic myeloid leukemia. To understand the underlying resistance mechanisms in response to imatinib mesylate (IMA) and adriamycin (ADR), the parental K562 cells were treated with low doses of IMA or ADR for 2 months to generate derivative cells with mild, intermediate, and severe resistance to the drugs as defined by their increasing resistance index. PulseDIA-based (DIA [data-independent acquisition]) quantitative proteomics was then employed to reveal the proteome changes in these resistant cells. In total, 7082 proteins from 98,232 peptides were identified and quantified from the dataset using four DIA software tools including OpenSWATH, Spectronaut, DIA-NN, and EncyclopeDIA. Sirtuin signaling pathway was found to be significantly enriched in both ADR-resistant and IMA-resistant K562 cells. In particular, isocitrate dehydrogenase (NADP(+)) 2 was identified as a potential drug target correlated with the drug resistance phenotype, and its inhibition by the antagonist AGI-6780 reversed the acquired resistance in K562 cells to either ADR or IMA. Together, our study has implicated isocitrate dehydrogenase (NADP(+)) 2 as a potential target that can be therapeutically leveraged to alleviate the drug resistance in K562 cells when treated with IMA and ADR.  相似文献   
52.
目的:探讨骨化三醇联合腹膜透析疗法治疗慢性肾功能衰竭的临床疗效及对患者血清Pro-Gastrin-Releasing Peptide (ProGRP)、CystatinC(Cysc)、Chemerin水平的影响。方法:选取我院2017年2月至2018年1月收治的98例慢性肾功能衰竭患者,按照随机数表法将其分为观察组(n=51)和对照组(n=47)。对照组采用腹膜透析疗法治疗,观察组采用骨化三醇联合腹膜透析疗法治疗。观察和比较两组治疗前后肾功能指标尿素氮(blood urea nitrogen,BUN)、血清肌酐(Serum creatinine Cr)、24小时尿蛋白(24 h urinary protein,24 h UP),生化指标白蛋白(albumin,Alb)、血红蛋白(hemoglobin,Hb)及红细胞(red blood cell,RBC),胃泌素释放肽前体(ProGRP)、血清胱抑素(Cys C)、趋化素(Chemerin)水平的变化,6个月、1年生存率及不良反应的发生情况。结果:治疗后,观察组BUN、SCr、24hUP水平均显著低于对照组[(13.95±3.06)mmol/L vs.(21.10±3.85)mmol/L,(260.12±40.32)μmol/L vs.(354.93±51.06)μmol/L,(1.75±0.45)g/24 h vs.(2.67±0.80)g/24 h](P0.05);Alb水平显著低于对照组[(27.85±3.58)g/L vs.(33.06±4.27)g/L](P0.05);Hb、RBC显著高于对照组[(91.72±13.46)g/L vs.(82.36±10.15)g/L,(379.47±92.08)×1012/L vs.(315.70±73.24)×1012/L](P0.05);ProGRP、Chemerin水平显著低于对照组[(49.23±4.72)pg/mL vs.(63.87±7.30)pg/mL,(37.02±6.15)μg/L vs.(30.63±4.81)μg/L](P0.05);Cysc水平显著高于对照组[(80.75±16.08)mL/min vs.(98.81±18.07)mL/min](P0.05);6个月、1年生存率均显著高于对照组[96.08%(49/51) vs. 91.49%(43/47),90.20%(46/51) vs. 74.47%(35/47)](P0.05);不良反应总发生率显著低于对照组[17.65%(9/51) vs. 44.68%(21/47)](P0.05)。结论:骨化三醇联合腹膜透析疗法治疗慢性肾功能衰竭的临床效果显著优于单用,其可有效减轻患者的临床症状,纠正电解质紊乱,改善肾功能和预后,可能与降低血清ProGRP、Chemerin水平及提高血清Cysc水平有关。  相似文献   
53.
慢性扁桃体炎与细菌L型感染   总被引:1,自引:0,他引:1  
通常认为,慢性扁桃体炎主要致病菌是金黄色葡萄球菌和乙型溶血性链球菌。通过50例慢性扁桃体炎的病原微生物培养、组织切片细菌学及电镜等研究,发现慢性扁桃体炎组织中细菌L型也相当常见,L型培养阳性率是88.5%,且组织切片L型感染率与培养阳性率基本一致(P>0.05)。电镜在扁桃体组织间质及上皮细胞、淋巴细胞等多种细胞内均见到细菌L型。提示慢性扁桃体炎与细菌L型感染关系极为密切。并认为,L型侵入组织并在宿主细胞内生长的特性,可能是慢性扁桃体炎反复发作、迁延不愈的重要原因。  相似文献   
54.
摘要 目的:探讨老年慢性心力衰竭(CHF)患者甲状腺激素(TH)水平与认知功能、心功能及心血管事件的关系。方法:将我院2018年6月~2020年6月收治的140例老年CHF患者纳入研究,检测患者TH指标[血清三碘甲状腺原氨酸(T3)、游离三碘甲状腺原氨酸(FT3)、甲状腺素(T4)、游离甲状腺素(FT4)、促甲状腺激素(TSH)]水平。按蒙特利尔认知评估量表(MoCA)评分将患者分为认知障碍组(MoCA评分<26分)、非认知障碍组(MoCA评分≥26分),比较两组各TH指标与MoCA评分。比较不同纽约心脏病协会(NYHA)分级患者的TH指标与心功能指标[左室射血分数(LVEF)、左室舒张末期内径(LVEDD)、左室收缩末期内径(LVESD)]。根据患者住院期间是否发生心血管事件分为心血管事件组和非心血管事件组,比较两组各TH指标。经Pearson线性相关分析TH指标与MoCA评分、心功能指标的相关性。结果:认知障碍组血清T3、FT3水平及MoCA评分较非认知障碍组明显降低(P<0.05)。Ⅲ级、Ⅳ级组的血清T3、FT3水平及LVEF较Ⅰ级、Ⅱ级组显著降低,其中Ⅳ级组低于Ⅲ级组(P<0.05)。Ⅲ级、Ⅳ级组的LVEDD、LVESD较Ⅰ级、Ⅱ级组明显升高,且Ⅳ级组高于Ⅲ级组(P<0.05)。心血管事件组血清T3、FT3水平较非心血管事件组显著降低(P<0.05)。Pearson线性相关分析显示:血清T3、FT3水平与MoCA评分、LVEF呈正相关(均P<0.05),与LVEDD、LVESD呈负相关(均P<0.05)。结论:老年CHF患者血清T3、FT3水平下调与其认知功能、心功能降低及心血管事件的发生密切相关,通过检测其血清T3、FT3水平,有利于进一步了解其病情变化。  相似文献   
55.
BACKGROUNDS: Recently, potential liver toxicity was discussed with the intake of kava extract preparations (Piper methysticum) as anxiolytic drugs. The aim of this study was to test chronic toxicity in rats by oral application of an ethanolic kava full extract. METHODS: Wistar rats of both sexes were fed 7.3 or 73 mg/kg body weight of ethanolic kava extract for 3 and 6 months. The animals were examined for changes in body weight, hematological and liver parameters, and macroscopical and microscopical histological changes in the major organs. RESULTS: No signs of toxicity could be found. CONCLUSIONS: The results are in accordance with the medical experience regarding the use of kava preparations and the long tradition of kava drinking in the South Pacific island states. Specifically, the results do not back the suspicion of potential liver toxicity.  相似文献   
56.
The optimisation of two series of 4-hydroxybenzothiazolone derived β2-adrenoceptor agonists, bearing α-substituted cyclopentyl and β-phenethyl amino-substituents, as inhaled long-acting bronchodilators is described. Analogues were selected for synthesis using a lipophilicity based hypothesis to achieve the targeted rapid onset of action in combination with a long duration of action. The profiling of the two series led to identification of the α-substituted cyclopentyl analogue 2 as the optimal compound with a comparable profile to the inhaled once-daily long-acting β2-adrenoceptor agonist indacaterol. On the basis of these data 2 was promoted as the backup development candidate to indacaterol from the Novartis LABA project.  相似文献   
57.
《Reproductive biology》2020,20(4):474-483
Infertility is a growing worldwide public health problem, and stress is a main factor exerting detrimental effects on female reproduction. However, knowledge regarding the neuroendocrine changes caused by chronic stress in females is limited. Therefore, this study assessed the effects of stress on hormones that control female reproduction during the proestrus and diestrus stages of the estrous cycle, as well as its effects on fertility. Adult females were assigned to either a control or a stress group. Stress consisted of exposure, for 15 min, to cold-water immersion daily for 30 days. Estrous cyclicity, female sexual behavior, as well as hypothalamic kisspeptin, gonadotropin releasing hormone (GnRH) content, serum luteinizing hormone (LH), estradiol (E2), progesterone (P4), corticosterone (CORT) and fertility were assessed after chronic stress. The results show that chronically stressed females exhibited disrupted estrous cyclicity, decreased receptivity, low pregnancy rates and lower numbers of fetuses. The content of Kisspeptin and GnRH in the Anteroventral Periventricular/medial Preoptic Area decreased during proestrus, while Kisspeptin increased in the Arcuate nucleus in proestrus and diestrus. Serum LH decreased only during proestrus, whereas E2 and P4 concentrations decreased during proestrus and diestrus, with a concomitant increase in CORT levels in both stages. As a whole, these results indicate that chronic stress decreases Kisspeptin content in AVPV nucleus and GnRH in POA in females, and might induce disruption of the LH surge, consequently disrupting estrous cyclicity and fertility, leading to lower rates of pregnancy and number of fetuses.  相似文献   
58.
摘要 目的:探讨布南色林联合团体心理治疗慢性精神分裂症(SZ)的疗效,分析其对认知功能、社会功能和服药依从性的影响。方法:选取124例慢性SZ患者随机分为对照组和观察组,对照组口服布南色林治疗,观察组在对照组基础上加以团体心理治疗,疗程均为2个月。治疗后,采用阳性与阴性症状量表(PANSS)和临床疗效总评量表-疾病严重程度(CGI-SI)评估两组患者治疗后的疗效,采用威斯康星卡片分类测验(WCST)评估两组患者治疗前后的认知功能,采用个人和社会功能量表(PSP)评估两组患者治疗前后的社会功能,评定两组患者治疗后的服药依从性。结果:治疗后,两组患者PANSS阳性症状、阴性症状、一般精神病理评分以及总评分均低于治疗前,且观察组低于对照组(P<0.05);两组患者CGI-SI评分均低于治疗前,且观察组低于对照组(P<0.05);两组患者WCST总应答数评分均高于治疗前,且观察组高于对照组(P<0.05);两组患者PSP总评分均高于治疗前,且观察组高于对照组(P<0.05);观察组服药依从性优于对照组(P<0.05)。结论:布南色林联合团体心理治疗较单一布南色林治疗慢性SZ的治疗效果更好,能更好地提高患者的认知功能、社会功能以及服药依从性,值得临床借鉴推广。  相似文献   
59.
Virologica Sinica - Hepatitis C virus (HCV) is still one of the main causes of liver disease worldwide. Metabolic disorders, including non-alcoholic fatty liver disease (NAFLD), induced by HCV have...  相似文献   
60.
纤连蛋白(FN)是参与乙型肝炎病毒感染和肝脏纤维化的重要分子。 蚓激酶(LK)是从赤子爱胜蚓(Eisenia foetide)中提取的一组蛋白水解同工酶,能水解纤维蛋白治疗凝血相关疾病。 从这组同工酶中分离纯化出单一活性成分,在体外可降解纤连蛋白,被命名为蚯蚓纤连蛋白水解酶(EFNase)。 然而,LK 能否预防乙型肝炎病毒感染以及缓解因乙型肝炎导致的肝脏损伤等问题还不清楚。本研究以人肝癌细胞系HepG2.2.15为细胞模型,观察LK 对乙型肝炎表面抗原(HBsAg)或 FN 水平的影响;以 C57BL / 6J-HBV 转基因小鼠为动物模型,探讨 LK 对小鼠血清中 HBsAg、FN、丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)水平及肝脏病理改变的影响。结果表明,LK 在体内外均能抑制HBsAg 的生成,降低血清和肝脏FN。与生理盐水处理组相比,LK 改善了肝脏的状态。这些数据为理解LK 作为治疗乙型肝炎的潜在有效药物的治疗作用提供了有价值的信息。  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