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   9413篇
  免费   564篇
  国内免费   1105篇
耳鼻咽喉   30篇
儿科学   330篇
妇产科学   26篇
基础医学   681篇
口腔科学   104篇
临床医学   870篇
内科学   4050篇
皮肤病学   43篇
神经病学   56篇
特种医学   173篇
外国民族医学   1篇
外科学   180篇
综合类   2117篇
预防医学   563篇
眼科学   9篇
药学   969篇
  6篇
中国医学   344篇
肿瘤学   530篇
  2024年   3篇
  2023年   76篇
  2022年   156篇
  2021年   193篇
  2020年   218篇
  2019年   110篇
  2018年   98篇
  2017年   181篇
  2016年   275篇
  2015年   330篇
  2014年   616篇
  2013年   799篇
  2012年   581篇
  2011年   616篇
  2010年   531篇
  2009年   512篇
  2008年   477篇
  2007年   592篇
  2006年   631篇
  2005年   635篇
  2004年   421篇
  2003年   501篇
  2002年   468篇
  2001年   466篇
  2000年   395篇
  1999年   282篇
  1998年   244篇
  1997年   196篇
  1996年   131篇
  1995年   100篇
  1994年   88篇
  1993年   50篇
  1992年   40篇
  1991年   39篇
  1990年   18篇
  1989年   4篇
  1988年   6篇
  1909年   1篇
  1907年   1篇
  1906年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
幽门螺杆菌(Helicobacter pylori,H.pylori)是一种可引发多系统病变的致病微生物。根除H.pylori能够改善胃黏膜炎性反应,阻止或延缓胃黏膜萎缩、肠化生的发生和发展,并部分逆转萎缩,也可不同程度地降低胃癌的发生率。以往临床常采用三联疗法作为根除H.pylori的一线治疗方案,但近年由于抗生素的广泛使用,导致H.pylori的抗药性增强,根除率降低。国内外研究均表明,链霉蛋白酶可以通过抑制H.pylori生存和影响抗H.pylori抗菌药起到根治的作用,并且在此方面取得良好疗效,为根除H.pylori开辟出一条崭新的道路。本文就链霉蛋白酶治疗H.pylori的进展作一概述。  相似文献   
3.
When several Helicobacter pylori eradication treatments fail, guidelines recommend a cultured guided approach; however, culture is not widely available. Therefore, a rifabutin based regimen could be the best solution. Rifabutin indeed shows a low rate of antibiotic resistance. Rifabutin is generally used in combination with amoxicillin in a triple therapy, with eradication rates about 80% in third-line regimens. The ideal duration of this therapy should range between 10 and 12 d. Combinations with antibiotics other than amoxicillin have demonstrated even better results, such as vonoprazan, which is a type of novel acid suppressor drug. Finally, a new formulation of triple therapy in a single capsule is under investigation, which is a field that deserves further investigation. Some notes of caution about rifabutin should be mentioned. This drug is used to treat tuberculosis or atypical mycobacteria; therefore, before starting a rifabutin-based eradication regimen, Mycobacterium tuberculosis infection should be thoroughly tested, since its use could promote the development of antibiotic resistance, thus affecting its effectiveness against Koch’s bacillus. Additionally, some serious side effects must be evaluated before starting any rifabutin-based therapy. Adverse effects include fever, nausea, vomiting and bone marrow suppression. For this reason, full blood count surveillance is required.  相似文献   
4.
目的 采取前瞻性设计、多中心随机对照临床研究方法,探讨国产内镜新光学染色技术——聚谱成像(spectral focused imaging,SFI)及光电复合染色成像(variable intelligent staining technology,VIST)对于胃癌前病变的诊断价值。方法 2020年8月—2021年5月,采用同一技术方案在河北医科大学第一医院、上海市第十人民医院、苏州大学附属第二医院,将拟行胃镜检查的患者随机分成白光组和新光学染色组,采取序贯检查方式(白光→新光学染色或新光学染色→白光),分别记录两组先行白光或先行新光学染色检查时的内镜诊断结果和幽门螺杆菌(Helicobacter pylori, HP)感染的判断结果;同时对两组的胃黏膜萎缩、肠上皮化生、皱襞肿大、结节性胃炎和弥漫性发红5个方面进行内镜胃癌风险评分。结果 共入组病例合计419例,白光组208例,新光学染色组211例。结合内镜及病理学结果,对胃内炎症、萎缩、肠上皮化生、低级别上皮内瘤变、高级别上皮内瘤变、进展期癌病变,白光组检出率分别为:28.9%、40.4%、64.9%、17.8%、0.5%、0.5%,新光学染色组检出率为:30.8%、42.7%、62.6%、15.2%、2.8%、0.5%,检出率组间差异无统计学意义(P>0.05);以病理结果为金标准,计算国产内镜诊断各类病变的灵敏度、特异度、准确度、阳性预测值、阴性预测值,对胃黏膜萎缩的诊断白光组分别为92.9%、61.3%、74.0%、61.9%、92.7%,新光学染色组(SFI模式)为94.4%、64.5%、77.3%、66.4%、94.0%;对胃黏膜肠上皮化生的诊断,白光组为68.1%、72.6%、69.7%、82.1%、55.2%,新光学染色组(VIST模式)为87.1%、89.9%、88.2%、93.5%、80.7%,两组间比较差异有统计学意义(P<0.05);以13C尿素呼气试验(13C?urea breath test, 13C?UBT)结果为金标准,对HP感染判断,白光组为90.2%、84.3%、87.4%、86.8%、88.2%,新光学染色组为92.6%、77.1%、85.4%、82.2%、90.1%;胃癌风险评分≥4分的病例,新光学染色组高危病变的占比更高(P<0.05)。结论 国产内镜新光学染色技术对胃黏膜肠上皮化生有较高的诊断价值,优于白光内镜;以胃癌风险评分为工具进行精查胃镜有助于胃癌前病变的检出;国产内镜新光学染色技术对胃癌前病变及HP感染诊断效能与进口内镜相近,是发现胃黏膜癌前病变的有效手段。  相似文献   
5.
Helicobacter pylori (H. pylori) is an infectious agent influencing as much as 50% of the world’s population. It is the causative agent for several diseases, most especially gastric and duodenal peptic ulcer, gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma of the stomach. A number of other, extragastric manifestations also are associated with H. pylori infection. These include neurological disorders, such as Alzheimer’s disease, demyelinating multiple sclerosis and Parkinson’s disease. There is also evidence for a relationship between H. pylori infection and such dermatological diseases as psoriasis and rosacea as well as a connection with infection and open-angle glaucoma. Generally little is known about the relationship between H. pylori infection and diseases of the pancreas. Most evidence about H. pylori and its potential role in the development of pancreatic diseases concerns pancreatic adenocarcinoma and autoimmune forms of chronic pancreatitis. There is data (albeit not fully consistent) indicating modestly increased pancreatic cancer risk in H. pylori-positive patients. The pathogenetic mechanism of this increase is not yet fully elucidated, but several theories have been proposed. Reduction of antral D-cells in H. pylori-positive patients causes a suppression of somatostatin secretion that, in turn, stimulates increased secretin secretion. That stimulates pancreatic growth and thus increases the risk of carcinogenesis. Alternatively, H. pylori, as a part of microbiome dysbiosis and the so-called oncobiome, is proven to be associated with pancreatic adenocarcinoma development via the promotion of cellular proliferation. The role of H. pylori in the inflammation characteristic of autoimmune pancreatitis seems to be explained by a mechanism of molecular mimicry among several proteins (mostly enzymes) of H. pylori and pancreatic tissue. Patients with autoimmune pancreatitis often show positivity for antibodies against H. pylori proteins. H. pylori, as a part of microbiome dysbiosis, also is viewed as a potential trigger of autoimmune inflammation of the pancreas. It is precisely these relationships (and associated equivocal conclusions) that constitute a center of attention among pancreatologists, immunologists and pathologists. In order to obtain clear and valid results, more studies on sufficiently large cohorts of patients are needed. The topic is itself sufficiently significant to draw the interest of clinicians and inspire further systematic research. Next-generation sequencing could play an important role in investigating the microbiome as a potential diagnostic and prognostic biomarker for pancreatic cancer.  相似文献   
6.
7.
目的:基于生物医学大数据筛选幽门螺杆菌(Hp)相关性慢性萎缩性胃炎的关键基因,探索其发病机制及安胃汤对其的影响。方法:从数据库Gene Expression Omnibus(GEO)下载Hp相关性慢性萎缩性胃炎相关芯片数据,利用GEO2R软件筛选出Hp相关性慢性萎缩性胃炎差异基因,进行生物信息学分析,根据蛋白参与通路数量确定核心蛋白,建立Hp阳性慢性萎缩性胃炎大鼠模型,用PCR和蛋白质印迹法(Western Blotting)进行检测并观察安胃汤对其表达的影响。结果:经过检索分析GSE13873和GSE27411系列芯片数据被纳入,取2个芯片交集的20个差异基因进行生物信息学分析,发现载脂蛋白A1、CD36、囊性纤维化穿膜传导调节蛋白(CFTR)可能是信号通路的核心蛋白。Western Blotting及PCR结果显示Hp相关性慢性萎缩性胃炎大鼠胃组织中,CD36蛋白表达下调(P<0.05),载脂蛋白A1和CFTR蛋白表达上调(P<0.05);与模型组比较,实验观察高剂量组、实验观察中剂量组和实验观察低剂量组胃组织中CD36蛋白表达上调,载脂蛋白A1和CFTR表达下调(P<0.05),其与Hp相关性慢性萎缩性胃炎发病关系密切。结论:通过对GEO中Hp相关性慢性萎缩性胃炎芯片生物信息学分析结合Western Blotting及PCR进一步的验证发现载脂蛋白A1、CD36、CFTR作为信号通路的核心蛋白实验结果与生物信息学分析结果一致。  相似文献   
8.
目的 探讨抗幽门螺杆菌(Hp)治疗对Hp阳性寻常型银屑病患者疗效的影响及Hp感染与寻常型银 屑病发病的可能机制。方法 选取2019年12月-2021年9月重庆三峡医药高等专科学校附属医院皮肤科确诊 的50例Hp阳性寻常型银屑病患者,采用随机数字表法分成试验组与对照组,每组25例。试验组予以外用卤 米松乳膏、卡泊三醇软膏联合四联抗Hp治疗,对照组予以外用卤米松乳膏、卡泊三醇软膏治疗,比较两组 治疗前、治疗后1个月PASI评分以及血清IL-17水平。结果 两组治疗后PASI评分低于治疗前,且试验组低 于对照组,差异有统计学意义(P<0.05);两组治疗后IL-17水平低于治疗前,且试验组低于对照组,差 异有统计学意义(P<0.05)。结论 对Hp阳性寻常型银屑病患者进行抗Hp治疗有利于提高患者临床疗效, Hp感染可能通过诱导血清IL-17水平升高而参与银屑病的发生与发展。  相似文献   
9.
BACKGROUND Helicobacter pylori(H.pylori)infection is known to prevent the occurrence of gastroesophageal reflux disease(GERD)by inducing gastric mucosal atrophy.However,little is known about the relationship between atrophic gastritis(AG)and GERD.AIM To confirm the inverse correlation between AG and the occurrence and severity of GERD.METHODS Individuals receiving health checkups who underwent upper gastrointestinal endoscopy at Seoul National University Healthcare System Gangnam Center were included.The grade of reflux esophagitis was evaluated according to the Los Angeles classification.Endoscopic AG(EAG)was categorized into six grades.Serologic AG(SAG)was defined as pepsinogen I≤70 ng/m L and pepsinogen I/II ratio≤3.0.The association between the extent of EAG and SAG and the occurrence and severity of GERD was evaluated using multivariate logistic regression analysis.RESULTS In total,4684 individuals with GERD were compared with 21901 healthy controls.In multivariate logistic regression analysis,advanced age,male sex,body mass index>23 kg/m2,presence of metabolic syndrome,current smoking,and alcohol consumption were associated with an increased risk of GERD.Seropositivity for H.pylori immunoglobulin G antibodies was associated with a decreased risk of GERD.There was an inverse correlation between the extent of EAG and occurrence of GERD:Odds ratio(OR),1.01[95%confidence interval(CI):0.90-1.14]in C1,0.87(0.78-0.97)in C2,0.71(0.62-0.80)in C3,0.52(0.44-0.61)in O1,0.37(0.29-0.48)in O2,and 0.28(0.18-0.43)in O3.Additionally,the extent of EAG showed an inverse correlation with the severity of GERD.The presence of SAG was correlated with a reduced risk of GERD(OR=0.49,95%CI:0.28-0.87,P=0.014).CONCLUSION The extent of EAG and SAG exhibited strong inverse relationships with the occurrence and severity of GERD.AG followed by H.pylori infection may be independently protect against GERD.  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