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   16004篇
  免费   997篇
  国内免费   564篇
耳鼻咽喉   40篇
儿科学   371篇
妇产科学   736篇
基础医学   1992篇
口腔科学   206篇
临床医学   1377篇
内科学   2741篇
皮肤病学   178篇
神经病学   702篇
特种医学   248篇
外国民族医学   3篇
外科学   1194篇
综合类   2421篇
预防医学   861篇
眼科学   116篇
药学   3036篇
  7篇
中国医学   734篇
肿瘤学   602篇
  2023年   123篇
  2022年   313篇
  2021年   446篇
  2020年   447篇
  2019年   326篇
  2018年   390篇
  2017年   404篇
  2016年   472篇
  2015年   433篇
  2014年   815篇
  2013年   1267篇
  2012年   781篇
  2011年   881篇
  2010年   724篇
  2009年   654篇
  2008年   698篇
  2007年   726篇
  2006年   673篇
  2005年   642篇
  2004年   603篇
  2003年   573篇
  2002年   492篇
  2001年   432篇
  2000年   410篇
  1999年   353篇
  1998年   303篇
  1997年   286篇
  1996年   295篇
  1995年   259篇
  1994年   229篇
  1993年   210篇
  1992年   200篇
  1991年   171篇
  1990年   164篇
  1989年   157篇
  1988年   140篇
  1987年   119篇
  1986年   104篇
  1985年   139篇
  1984年   144篇
  1983年   86篇
  1982年   90篇
  1981年   69篇
  1980年   71篇
  1979年   49篇
  1978年   42篇
  1977年   42篇
  1976年   31篇
  1975年   23篇
  1974年   21篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
ABSTRACT

Introduction

Type 1 diabetes mellitus (T1DM) is a chronic, autoimmune disease that is characterized by total absence of insulin production. Hypertension is a common comorbidity in T1DM with complex pathophysiology, while it is also a well-recognized risk factor for the development of cardiovascular disease (CVD), as well as other microvascular diabetic complications.  相似文献   
3.
冠状病毒(coronavirus,CoVs)感染主要累及肺部,但对心血管系统损伤作用也不容忽视。CoVs感染引起的心脏损伤并非罕见,其发生与病情的严重程度密切相关。本文首先从CoVs引起心血管损伤的证据入手,进一步探讨了CoVs对心肌的直接损伤,以及肾素血管紧张素(RAS)系统激活和细胞因子风暴与炎症反应对心血管损伤的可能作用机制。相关心血管损伤的可能机制包括,(1)病毒直接作用:CoVs在心肌细胞复制,损伤心肌;(2)RAS系统激活:感染CoVs后,心脏血管紧张素转化酶2(angiotensin-converting enzyme 2,ACE2)的表达下调,激活RAS系统,使得血管紧张素Ⅱ(AngiotensinⅡ,AngⅡ)收缩血管功能增强,Ang1-7保护心脏效应减弱;(3)诱发细胞因子风暴:循环细胞因子和全身炎症反应引起心脏损伤;(4)其他:包括低氧血症和儿茶酚胺心脏毒性。本文就相关内容作一综述,为后续的详尽机制和治疗策略研究提供思路。  相似文献   
4.
  1. Butyrylcholinesterase (BChE) is a serine esterase that plays a role in the detoxification of natural as well as synthetic ester-bond-containing compounds. Alterations in BChE activity are associated with a number of diseases. Cholinergic system abnormalities in particular are correlated with the formation of senile plaques in Alzheimer’s disease (AD), and administration of cholinesterase inhibitors is a common therapeutic approach used to treat AD.

  2. Here, our aim was to study the interaction between BChE and fluoxetine.

  3. Molecular docking simulations revealed that fluoxetine penetrated deep into the active-site gorge of BChE and that it was engaged in stabilizing noncovalent interactions with multiple subsites. In substrate kinetic studies, the Vm, Km, kcat and kcat/Km values were found to be 20.59?±?0.36?U mg?1 protein, 194?±?14?µM, 1.3?×?108?s?1 and 6.7?×?105?µM?1s?1, respectively. Based on inhibitory studies, fluoxetine appeared to inhibit BChE competitively, with an IC50 value of 104?µM and a Ki value of 36.3?±?4.7?µM.

  4. Overall, both the low Ki value and the high number of BChE–fluoxetine interactions suggest that fluoxetine is a potent inhibitor of BChE, although in vivo mechanisms for the direct effects of BChE inhibition on various pathologies remain to be further investigated.

  相似文献   
5.
6.
7.
Risk is a concept inherent in every medical procedure. It can be defined as the probability of an adverse event in a defined population over a specified period of time. In the frame of food allergy management, it might be related to a diagnostic procedure, a treatment, or the consumption of foods. The risk of an adverse event can also be augmented by individual factors. This rostrum article discusses various aspects faced by children with food allergies in the light of risk, and their practical implications. Identifying personal risks for severe reaction, such as unstable asthma, and correcting them whenever possible also contribute to a reduction of the risk inherent to food allergy. Among the facets discussed, oral food challenges (OFC) are the most common diagnostic procedures implying an inherent risk. The risk of OFCs can be minimized by correct indication and timing of the test, a safe setting, as well as by ensuring that the patient is otherwise well without potential stressor potentially increasing the risk of a more severe reaction. Oral immunotherapy (OIT) has been studied as a potential treatment for increasing the threshold dose for reaction, and thus reducing the risk of accidental reaction. Nevertheless, the procedure is not devoid of risk as the patients may and do often react during the course of the procedure. Ingestion of trace amounts in processed foods, mainly in community settings such as restaurants, schools, or day care, represents a potential risk of reactions, although for a minority of patients. Precautionary allergen labeling (PAL) is a widespread strategy to reduce the potential risk of reactions due to traces. However, PAL is currently inefficient due to inconsistent labeling, also not indicating a clear maximum amount possibly present in the manufactured food. Finally, cost-effectiveness needs to be considered in risk management, as many risk reduction procedures are clearly not cost-effective.  相似文献   
8.
通过分析中国马拉松运动员ACE基因I/D多态频率分布特征,探讨其作为杰出耐力基因标记的可行性。选择我国马拉松健将、国际健将级运动员26名作为马拉松运动员组,汉族学生216名作为对照组。对两组受试者进行ACE基因I/D多态性测定。结果显示:我国马拉松运动员组的等位基因频率和基因型频率与对照组比较无显著差异,其中15名国际健将中无一DD型纯合子,提示我国优秀马拉松运动员的纯合子DD型频率低下是其ACE基因多态频率分布的主要特征。  相似文献   
9.
The risks of induction must be carefully weighed against the risks of allowing the pregnancy to continue and not inducing labor. The aim of the study was to show labor and neonatal outcome of 335 deliveries inducted in 2004 at Institute of gynecology and obstetrics Clinical Center of Serbia. Inductions were performed with PGE2, PGE1 and Oxytocin. The best ripening effect was noted in PGE2 group. The average duration of labor was 8.6h in PGE1group, 5.9h in PGE2 group and 10.4h in OT group. Sixty eight labors finished with cesarean section (20%). Comparing duration of labor, percentage of emergency cesarean sections, incidence of fetal distress during the labor we suggest Dinoprostone, placed intracervically, as an agent of choice for induction of labor.  相似文献   
10.
Here we retrospectively examine the efficacy of two antibody induction regimens using Zenapax or Thymoglobulin in patients with positive complement-dependent cytotoxicity crossmatches (CDC-CMXs) desensitized with IVIG (intravenous immunoglobulin). Between January 1999 and March 2005, 97 patients with (+) CDC-CMXs received kidney transplants (43 deceased donors/54 living donors). All patients received at least 2 g/kg IVIG (maximum four doses) until an acceptable CMX was obtained. Patients were divided into two groups: 1. IVIG + Zenapax (n = 58), 2. IVIG + Thymoglobulin (n = 39). A total of 94% of patients in Group 1 and 84% in G2 have at least 2 years of follow up. Patient and graft survival was 96%/84% in Group 1 and 100%/90% in Group 2, p = NS. The number and severity of AR episodes were similar (36% Group 1 vs. 31% Group 2, p = NS) as was the incidence of C4d (+) antibody-mediated rejection (AMR) (Banff Grade II/III) (22% Group 1 vs. 21% Group 2). Mean serum creatinines (SCrs) at 24 months were similar (Group 1: 1.4 +/- 0.7 vs. G2: 1.5 +/- 0.7 mg/dL). Induction therapy with Zenapax or Thymoglobulin results in excellent patient, graft survival and graft function at 2 years. There was no increased risk of viral infections or malignancies with either agent. Neither agent was effective in reducing the incidence of AMR.  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