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   4430662篇
  免费   364612篇
  国内免费   26430篇
耳鼻咽喉   62302篇
儿科学   134445篇
妇产科学   113657篇
基础医学   672085篇
口腔科学   121252篇
临床医学   408611篇
内科学   796182篇
皮肤病学   104929篇
神经病学   373663篇
特种医学   175667篇
外国民族医学   1008篇
外科学   666380篇
综合类   153649篇
现状与发展   62篇
一般理论   2594篇
预防医学   372098篇
眼科学   104571篇
药学   319092篇
  213篇
中国医学   21935篇
肿瘤学   217309篇
  2021年   64447篇
  2020年   42281篇
  2019年   64100篇
  2018年   78830篇
  2017年   61205篇
  2016年   67059篇
  2015年   83077篇
  2014年   119416篇
  2013年   183822篇
  2012年   130269篇
  2011年   134268篇
  2010年   131451篇
  2009年   132438篇
  2008年   116409篇
  2007年   122176篇
  2006年   131304篇
  2005年   126333篇
  2004年   124081篇
  2003年   114323篇
  2002年   104262篇
  2001年   156437篇
  2000年   152990篇
  1999年   142101篇
  1998年   72845篇
  1997年   69350篇
  1996年   66884篇
  1995年   62724篇
  1994年   56688篇
  1993年   52293篇
  1992年   104418篇
  1991年   99752篇
  1990年   94671篇
  1989年   92256篇
  1988年   85831篇
  1987年   84187篇
  1986年   79762篇
  1985年   78163篇
  1984年   66047篇
  1983年   58929篇
  1982年   48181篇
  1981年   44943篇
  1980年   42202篇
  1979年   57883篇
  1978年   47050篇
  1977年   41606篇
  1976年   38669篇
  1975年   37857篇
  1974年   42432篇
  1973年   40564篇
  1972年   38024篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.

Background

We have recently shown that human epididymis protein 4 (HE4) levels correlate with the severity of cystic fibrosis (CF) lung disease. However, there are no data on how HE4 levels alter in patients receiving CFTR modulating therapy.

Methods

In this retrospective clinical study, 3 independent CF patient cohorts (US-American: 29, Australian: 12 and Irish: 19 cases) were enrolled carrying at least one Class III CFTR CF-causing mutation (p.Gly551Asp) and being treated with CFTR potentiator ivacaftor. Plasma HE4 was measured by immunoassay before treatment (baseline) and 1–6?months after commencement of ivacaftor, and were correlated with FEV1 (% predicted), sweat chloride, C-reactive protein (CRP) and body mass index (BMI).

Results

After 1?month of therapy, HE4 levels were significantly lower than at baseline and remained decreased up to 6?months. A significant inverse correlation between absolute and delta values of HE4 and FEV1 (r?=??0.5376; P?<?.001 and r?=??0.3285; P?<?.001), was retrospectively observed in pooled groups, including an independent association of HE4 with FEV1 by multiple regression analysis (β?=??0.57, P?=?.019). Substantial area under the receiver operating characteristic curve (ROC-AUC) value was determined for HE4 when 7% mean change of FEV1 (0.722 [95% CI 0.581–0.863]; P?=?.029) were used as classifier, especially in the first 2?months of treatment (0.806 [95% CI 0.665–0.947]; P?<?.001).

Conclusions

This study shows that plasma HE4 levels inversely correlate with lung function improvement in CF patients receiving ivacaftor. Overall, this potential biomarker may be of value for routine clinical and laboratory follow-up of CFTR modulating therapy.  相似文献   
995.
996.
后Pilon骨折是一种新近报道的Pilon骨折的特殊模式,其特征是累及后外踝和后内踝.在过去由于后Pilon骨折没有得到充分的认识,常被误诊为后踝骨折,也导致这类患者功能恢复不良.因此是否能作出正确诊断至关重要,只有熟悉后Pilon骨折的各种影像学特征并了解合并损伤的机制,才能及时、准确地诊断后Pilon骨折,并改进这种具有挑战性骨折的术前计划和临床结果.本文着重介绍了后Pilon骨折的损伤机制,现有的分类方案,并讨论了目前使用的各种手术方法.  相似文献   
997.
目的 探讨microRNA-613调控细胞周期蛋白依赖性激酶14(CDK14)通路来抑制老年胶质瘤患者瘤细胞增殖和侵袭的机制。方法 购自上海北诺生物科技有限公司的人脑胶质瘤细胞株U251共24株,分为shNC组、shmicroRNA-613组、Vector组、microRNA-613组,每组各6株; Western Blotting法和qRT-PCR法检测敲减microRNA-613和过表达microRNA-613后的人脑胶质瘤细胞株U251中CDK14蛋白表达水平,CCK-8细胞增殖实验、Transwell小室实验验证敲除microRNA-613和过表达microRNA-613后U251细胞的增殖、侵袭能力。结果 人胶质瘤细胞株U251敲减microRNA-613后CDK14蛋白表达增加(P<0.05); 人胶质瘤细胞株U251过表达microRNA-613后CDK14蛋白表达减少(P<0.05); 转染第24、36、48 h microRNA-613组U251细胞增殖率P<0.05); microRNA-613组U251细胞侵袭能力>Vector组,shNC组>shmicroRNA-613组(P<0.05)。结论 microRNA-613可通过调控CDK14信号转导通路来抑制人脑胶质瘤细胞U251增殖、转移。  相似文献   
998.
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   
999.
1000.
BACKGROUND AND PURPOSE:Embolization of the middle meningeal artery for treatment of refractory or recurrent chronic subdural hematomas has gained momentum during the past few years. Little has been reported on the use of the n-BCA liquid embolic system for middle meningeal artery embolization. We present the technical feasibility of using diluted n-BCA for middle meningeal artery embolization.MATERIALS AND METHODS:We sought to examine the safety and technical feasibility of the diluted n-BCA liquid embolic system for middle meningeal artery embolization. Patients with chronic refractory or recurrent subdural hematomas were prospectively enrolled from September 2019 to June 2020. The primary outcome was the safety and technical feasibility of the use of diluted n-BCA for embolization of the middle meningeal artery. The secondary end point was the efficacy in reducing hematoma volume.RESULTS:A total of 16 patients were prospectively enrolled. Concomitant burr-hole craniotomies were performed in 12 of the 16 patients. Two patients required an operation following middle meningeal artery embolization for persistent symptoms. The primary end point was met in 100% of cases in which there were no intra- or postprocedural complications. Distal penetration of the middle meningeal artery branches was achieved in all the enrolled cases. A 7-day post–middle meningeal artery embolization follow-up head CT demonstrated improvement (>50% reduction in subdural hematoma volume) in 9/15 (60%) patients, with 6/15 (40%) showing an unchanged or stable subdural hematoma. At day 21, available CT scans demonstrated substantial further improvement (>75% reduction in subdural hematoma volume).CONCLUSIONS:Embolization of the middle meningeal artery using diluted n-BCA and ethiodized oil (1:6) is safe and feasible from a technical standpoint. The use of a dextrose 5% bolus improves distal penetration of the glue.

Despite traditional treatment with surgical evacuation, chronic subdural hematomas (cSDHs) tend to have an indolent course with frequent recurrences.1 In recent years, embolization of the middle meningeal artery (MMA) for treatment of refractory or recurrent cSDH has gained momentum, with recent literature showing a significant reduction in the size of the cSDH as well as lower rates of recurrence.2 The primary endovascular techniques used to date have involved the use of polyvinyl alcohol particles (PVA) and Onyx liquid embolic (ethylene-vinyl alcohol dissolved in dimethyl-sulfoxide; Medtronic). Another commonly used liquid embolic agent in the neurointerventional area is n-BCA, which is a liquid adhesive that polymerizes rapidly on contact with ionic substances and can be injected to achieve permanent vessel occlusion. The rates of polymerization and flow and the penetration depth can be modified using varying amounts of ethiodized oil as well as concurrent infusion of dextrose 5% in water (D5W) during n-BCA (Trufill, Cordis Neurovascular) injection (D5W-push technique).3 Data on the use of n-BCA as an embolic agent in cases of cSDH are extremely limited. Herein, we sought to study the safety and technical feasibility of using diluted n-BCA for embolization of the MMA for cSDHs.  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