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   197485篇
  免费   16755篇
  国内免费   7113篇
耳鼻咽喉   1616篇
儿科学   2533篇
妇产科学   2209篇
基础医学   31696篇
口腔科学   3298篇
临床医学   14339篇
内科学   34201篇
皮肤病学   2762篇
神经病学   14914篇
特种医学   4273篇
外国民族医学   55篇
外科学   13192篇
综合类   26385篇
现状与发展   19篇
一般理论   6篇
预防医学   9271篇
眼科学   1970篇
药学   32556篇
  45篇
中国医学   8345篇
肿瘤学   17668篇
  2024年   342篇
  2023年   3556篇
  2022年   4988篇
  2021年   10111篇
  2020年   7636篇
  2019年   6507篇
  2018年   6277篇
  2017年   6330篇
  2016年   6459篇
  2015年   7542篇
  2014年   11827篇
  2013年   13354篇
  2012年   11742篇
  2011年   13484篇
  2010年   11128篇
  2009年   11344篇
  2008年   10957篇
  2007年   9897篇
  2006年   8830篇
  2005年   7765篇
  2004年   6498篇
  2003年   5781篇
  2002年   4578篇
  2001年   3718篇
  2000年   3129篇
  1999年   2834篇
  1998年   2653篇
  1997年   2456篇
  1996年   2198篇
  1995年   1948篇
  1994年   1765篇
  1993年   1526篇
  1992年   1279篇
  1991年   1210篇
  1990年   994篇
  1989年   834篇
  1988年   795篇
  1987年   666篇
  1986年   601篇
  1985年   1008篇
  1984年   958篇
  1983年   686篇
  1982年   698篇
  1981年   555篇
  1980年   470篇
  1979年   396篇
  1978年   255篇
  1977年   200篇
  1976年   188篇
  1975年   124篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
121.
《Vaccine》2019,37(31):4382-4391
Cancer-associated fibroblasts (CAFs), major components of the tumor microenvironment (TME), promote tumor growth and metastasis and inhibit the anti-tumor immune response. We previously constructed a DNA vaccine expressing human FAPα, which is highly expressed by CAFs, to target these cells in the TME, and observed limited anti-tumor effects in the 4T1 breast cancer model. When the treatment time was delayed until tumor nodes formed, the anti-tumor effect of the vaccine completely disappeared. In this study, to improve the safety and efficacy, we constructed a new FAPα-targeted vaccine containing only the extracellular domain of human FAPα with a tissue plasminogen activator signal sequence for enhanced antigen secretion and immunogenicity. The number of CAFs was more effectively reduced by CD8+ T cells induced by the new vaccine. This resulted in decreases in CCL2 and CXCL12 expression, leading to a significant decrease in the ratio of myeloid-derived suppressor cells in the TME. Moreover, when mice were treated after the establishment of tumors, the vaccine could still delay tumor growth. To facilitate the future application of the vaccine in clinical trials, we further optimized the gene codons and reduced the homology between the vaccine and the original sequence, which may be convenient for evaluating the vaccine distribution in the human body. These results indicated that the new FAPα-targeted vaccine expressing an optimized secreted human FAPα induced enhanced anti-tumor activity by reducing the number of FAPα+ CAFs and enhancing the recruitment of effector T cells in the 4T1 tumor model mice.  相似文献   
122.
Background/objectiveObstructive sleep apnea (OSA) is independently associated with dyslipidemia, a surrogate marker of atherosclerosis. Low-density lipoprotein (LDL)-cholesterol is accepted as a major independent risk factor for cardiovascular disease. However, non-high-density lipoprotein (HDL)-cholesterol is a better marker of atherogenic dyslipidemia and recommended as a target of lipid lowering therapy. We aimed to assess the prevalence of atherogenic dyslipidemia, and relationship between OSA severity and serum LDL-cholesterol and non-HDL cholesterol levels in OSA patients.MethodsWe retrospectively evaluated treatment naïve 2361 subjects admitted to the sleep laboratory of a university hospital for polysomnography. All subjects’ lipid profile including total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and non-HDL-cholesterol were measured.ResultsOut of 2361 patients (mean age 49.6 ± 11.9 years; 68.9% male, apnea-hypopnea index 36.6 ± 28.4/h), 185 (7.8%) had no OSA and 2176 (92.2%) had OSA. Atherogenic dyslipidemia prevalence was high (57–66%) in OSA patients, and especially increased in severe OSA compared to other groups (p < 0.05). Though total and LDL-cholesterol did not differ between those with and without OSA, non-HDL-cholesterol (p = 0.020), and triglycerides (p = 0.001) were higher and HDL-cholesterol levels (p = 0.018) were lower in OSA patients than non-OSA. Non-HDL-cholesterol was significantly correlated with OSA severity (p < 0.001) and hypoxia parameters (p < 0.01), whereas LDL-cholesterol showed no correlation.ConclusionsAtherogenic dyslipidemia is highly prevalent and non-HDL-cholesterol levels are significantly increased, predominantly in severe OSA patients. Non-HDL-cholesterol but not LDL-cholesterol, is significantly correlated with OSA severity and hypoxia parameters. Therefore, it could be better to use non-HDL-cholesterol, which is a guideline recommended target of lipid therapy, as a marker of atherosclerotic cardiovascular risk in OSA patients.  相似文献   
123.
BackgroundConsiderable progress has been made in therapeutic options for multiple myeloma (MM). Understanding the current landscape of MM treatment options and associated outcomes in the real world is important in providing key insights into clinical and knowledge gaps which could be targeted for further optimization.MethodsThe Canadian Myeloma Research Group Database (CMRG-DB) is a prospectively maintained disease-specific database with >7000 patients. The objective of this study was to describe the trends in the treatment landscape and outcomes including early mortality, time to next treatment, and overall survival (OS) in each line of treatment stratified by autologous stem cell transplant (ASCT) receipt among newly-diagnosed MM patients in Canada between 2007 and 2018.ResultsA total of 5154 patients were identified among which 3030 patients (58.8%) received an upfront ASCT and 2124 (41.2%) did not. At diagnosis, the median age was 64 years and 58.6% were males. Bortezomib and lenalidomide were most frequently used (>50%) in first and second-line treatment respectively among both the ASCT and non-ASCT cohort. The median OS was 122.0 months (95% Cl 115.0-135.0 months) and 54.3 months (95% CI 50.8-58.8 months) for the ASCT and non-ASCT cohort respectively with an incremental decrease in OS in each subsequent line of treatment.ConclusionWe present the largest study to date in the Canadian landscape showing the characteristics, therapy usage, and outcomes among MM patients. This information will be critical in benchmarking current outcomes and provide key insight into areas of unmet needs and gaps for improvement of MM patients nationally.  相似文献   
124.
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction.  相似文献   
125.
《Ticks and Tick》2020,11(6):101547
Ferritin 2 (FER2) is an iron storage protein, which has been shown to be critical for iron homeostasis during blood feeding and reproduction in ticks and is therefore suitable as a component for anti-tick vaccines. In this study, we identified the FER2 of Ixodes persulcatus, a major vector for zoonotic diseases such as Lyme borreliosis and tick-borne relapsing fever in Japan, and investigated its functions. Ixodes persulcatus-derived ferritin 2 (Ip-FER2) showed concentration-dependent iron-binding ability and high amino acid conservation, consistent with FER2s of other tick species. Vaccines containing the recombinant Ip-FER2 elicited a significant reduction of the engorgement weight of adult I. persulcatus. Interestingly, the reduction of engorgement weight was also observed in Ixodes ovatus, a sympatric species of I. persulcatus. In silico analyses of FER2 sequences of I. persulcatus and other ticks showed a greater similarity with I. scapularis and I. ricinus and lesser similarity with Hyalomma anatolicum, Haemaphysalis longicornis, Rhipicephalus microplus, and R. appendiculatus. Moreover, it was observed that the tick FER2 sequences possess conserved regions within the primary structures, and in silico epitope mapping analysis revealed that antigenic regions were also conserved, particularly among Ixodes spp ticks. In conclusion, the data support further protective tick vaccination applications using the Ip-FER2 antigens identified herein.  相似文献   
126.
习洋  陶泽璋 《疑难病杂志》2020,(2):207-211,216
慢性鼻窦炎(CRS)是一种常见的慢性非特异感染性鼻部疾病,病理分型主要分为Th2细胞介导的嗜酸性粒细胞性鼻窦炎(ECRS)和Th1细胞介导的非嗜酸性粒细胞性鼻窦炎(非ECRS)2种表型。欧洲国家CRS患病人群主要表现为ECRS,而随着亚洲国家的急剧工业化发展,其ECRS的比例也在急剧增加。ECRS发病机制复杂,涉及多种免疫细胞和相关因子相互作用。其治疗方法包括抗生素、激素药物治疗及手术治疗等,但仍有部分患者症状难以改善或存在复发的风险。Ⅱ型固有淋巴样细胞(ILC2s)是一种非B、非T的新型淋巴细胞,与Th2免疫应答关系密切。文章就ILC2s在ECRS发病机制中的作用进行综述,以期为ECRS的诊断和治疗提供理论参考。  相似文献   
127.
目的:探讨2型糖尿病(T2DM)患者不同脂质参数与糖尿病肾病(DKD)发生的相关性。方法:检测226例T2DM患者血清TC、TG、LDL-C、HDL-C水平及相关生化指标,计算血浆致动脉硬化指数(AIP)以及脂质三角相关指标(TC/HDL-C、TG/HDL-C、LDL-C/HDL-C)。根据DKD临床诊断标准和Mogensen分期标准分为:Ⅰ~Ⅱ期组136例,Ⅲ期组55例,Ⅳ~Ⅴ期组35例。应用多因素logistic回归分析不同脂质参数与DKD发生的关系。结果:与Ⅰ~Ⅱ期组相比,随着DKD分期加重,TC、TG、LDL-C、LDL-C/HDL-C、AIP水平明显增高(P<0.01)。LDL-C/HDL-C和AIP与24 h尿蛋白水平呈正相关(r=0.724;r=0.769,均P<0.05)。LDL-C/HDL-C和AIP是T2DM合并DKD患者的独立预测因子(P=0.002;P=0.004)。结论:LDL-C/HDL-C和AIP对T2DM合并DKD病情进展有较高的预测价值,可为临床诊治提供参考。  相似文献   
128.
目的探讨新诊断2型糖尿病(T2DM)常见中医证型与非酒精性脂肪肝(NAFLD)及其相关危险因素的相关性,为中西医结合治疗提供临床指导。方法选择沧州中西医结合医院门诊和病房收治的300例新诊断T2DM患者作为研究对象,根据其是否合并NAFLD分为合并NAFLD组,单纯T2DM组。记录2组一般资料,依照《糖尿病中医防治指南》对所有患者进行辨证分型,记录2组腰围、身高、体质量、体质量指数(BMI)、肝功指标[丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、γ-谷氨酰转肽酶(GGT)、碱性磷酸酶(ALP)]、血脂指标(TG、TC、HDL-C、LDL-C)及血尿酸(SUA)、空腹血糖(FPG)、空腹胰岛素(FINS)、空腹C-肽(FC-P)、胰岛素抵抗指数(HOMA-IR),分析各中医证型与客观化指标的关系。结果合并NAFLD组124例,单纯T2DM组176例,2组性别、年龄比较差异无统计学意义(P均>0.05);合并NAFLD组的痰湿郁阻证占比明显高于T2DM组(P<0.05),其余分型占比组间比较差异无统计学意义(P均>0.05);合并NAFLD组的腰围、BMI、TG、TC、FC-P、HOMA-IR均显著高于T2DM组(P均<0.05),其余指标2组比较差异无统计学意义(P均>0.05);非条件Logistic回归分析显示,NAFLD的独立危险因素为BMI、TG、HOMA-IR。结论痰湿郁阻证是T2DM合并NAFLD患者的最常见证型,肥胖、胰岛素抵抗、脂质代谢紊乱是T2DM合并NAFLD患者的独立危险因素。  相似文献   
129.
HER2-positive breast cancer is an aggressive subtype identified in the 1980s. The development of therapies targeting the HER2 has improved outcomes. The current standard of care, established in 2012 is dual blockade with trastuzumab + pertuzumab as first-line followed by TDM-1 as second-line. Several suboptimal choices are available in third-line or more. In 2019 the presentation of several trials evaluating new drugs and regimens in third-line has re-opened questions about sequencing, treatment of triple positive disease and treatment choice after exposure to TDM-1. These include tucatinib, neratinib and trastuzumab-deruxtecan. Other agents – including other antibody drug conjugates and bispecific antibodies as well as combinations - will lead to further changes in coming years. Additionally, should the numerous putative biomarkers thus identified ever come into use at the clinic, choice of treatment and response evaluation may be substantially changed.  相似文献   
130.
目的探讨中药方剂四君子汤对脾胃虚弱症型消化性溃疡患者肠道菌群变化、环氧化酶(COX-1、COX-2)及前列腺素E2表达水平的影响。方法从2017年1月-2018年12月收治的消化性溃疡患者中按年龄组、性别、溃疡类型1∶1匹配后,随机分配于试验组与对照组(试验组与对照组各240名患者)。其中,对照组患者给予思密达治疗,试验组使用思密达协同四君子汤,分别治疗8周。比较治疗前后2组患者的治疗效果、肠道微生态变化、环氧化酶及前列腺素E2水平表达情况。结果治疗后,试验组的阳性与阴性杆菌数减少,阳性球菌数增多,且阳性球菌与阴性球菌数量均高于对照组。而对照组的阳性、阴性杆菌与阴性球菌均显著减少(P<0.05);2组的COX-1、COX-2、PGE2表达水平均增高(P<0.05),且中药组显著高于对照组(P<0.05)。结论在思密达基础上加用四君子汤治疗脾胃虚弱症型消化性溃疡可有效调节其胃肠道菌群平衡、增强对胃黏膜的覆盖保护作用。  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