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   28612篇
  免费   2536篇
  国内免费   85篇
耳鼻咽喉   304篇
儿科学   1107篇
妇产科学   586篇
基础医学   3633篇
口腔科学   440篇
临床医学   3569篇
内科学   4895篇
皮肤病学   504篇
神经病学   2808篇
特种医学   962篇
外国民族医学   1篇
外科学   3992篇
综合类   634篇
一般理论   23篇
预防医学   3437篇
眼科学   431篇
药学   2090篇
中国医学   45篇
肿瘤学   1772篇
  2023年   235篇
  2022年   335篇
  2021年   788篇
  2020年   435篇
  2019年   755篇
  2018年   882篇
  2017年   616篇
  2016年   599篇
  2015年   692篇
  2014年   944篇
  2013年   1333篇
  2012年   1895篇
  2011年   1955篇
  2010年   1084篇
  2009年   957篇
  2008年   1525篇
  2007年   1548篇
  2006年   1469篇
  2005年   1447篇
  2004年   1291篇
  2003年   1229篇
  2002年   1180篇
  2001年   650篇
  2000年   575篇
  1999年   496篇
  1998年   270篇
  1997年   228篇
  1996年   267篇
  1995年   204篇
  1994年   217篇
  1993年   171篇
  1992年   360篇
  1991年   354篇
  1990年   373篇
  1989年   358篇
  1988年   298篇
  1987年   315篇
  1986年   240篇
  1985年   265篇
  1984年   220篇
  1983年   168篇
  1982年   145篇
  1981年   113篇
  1980年   125篇
  1979年   170篇
  1978年   144篇
  1977年   110篇
  1976年   105篇
  1974年   128篇
  1973年   110篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
AIM: This paper is a report of a study to examine how nurse practitioners combine information when estimating patient risk of coronary heart disease. BACKGROUND: In the United States of America and other countries, nurse practitioners are increasingly working alongside physicians in primary healthcare settings. Given this role, nurse practitioners represent an important resource in early detection of numerous diseases. Understanding how nurse practitioners use patient characteristics (cues) to form estimates of patient risk for disease may improve general disease prevention efforts. METHOD: Social judgment theory and its lens model analysis are concerned with the correspondence between a person's judgments and the environment. This approach was applied to examine how 15 nurse practitioners weighted eight risk factors for coronary heart disease, how accurate practitioners were in assessing patient risk for coronary heart disease, and how much self-insight practitioners had into their own risk estimation processes. The data were collected in 2006. RESULTS: Nurse practitioners showed moderate to high accuracy and evinced a variety of cue-weighting strategies. Insight into their own judgment policies was modest. The lens model analysis revealed that most practitioners had lower values on knowledge of the ecology than they did on cognitive control. CONCLUSION: Educational efforts aimed at improving detection of patients at risk for diseases might do better to target increasing clinicians' understanding of cue-criteria relationships, than to stress themes of consistency in evaluating patients.  相似文献   
952.
Objective: Clinical literature was examined for evidence supporting use of CAD/CAM reconstructions and fiber‐reinforced materials. Materials and methods: Potential evidence was identified via databases [PubMed; EMBASE (R) Drugs & Pharmacology; Center for Reviews and Dissemination, University of York; Cochrane Library], hand search of non‐indexed literature, secondary reference searches, and personal contacts with clinical trial PI's. Search terms included: dental restorations; CAD/CAM; CEREC; LAVA; CERCON; Procera; inlay/onlay; dental prosthesis; fiber‐reinforced composite (FRC). Results: Two randomized‐controlled clinical trials were identified as examined in one Cochrane Collaboration review relevant to CAD/CAM inlays. One systematic review of 15 CAD/CAM inlay studies was examined. Six studies were identified of three commercial FRC endodontic posts and eight reported on FRC use for fixed denture prostheses. Fifteen ongoing prospective trials were identified studying CAD/CAM fabricated zirconia‐based prostheses. A total of 76 papers were referenced including those related to use of in vitro measures as evidence. Conclusions: Review of the Cochrane analysis raised concerns that typical RCT protocols may prove insufficient for stratification of confounding variables (patient, practitioner, material) when treatment outcomes are primarily prosthesis‐ or material‐based (not patient‐based, e.g., as in fracture). RCT designs are most straightforward when treatment outcomes are patient‐based (e.g., soft tissue changes). When treatment responses are material‐based, controls also become difficult to define and studies become tests of equivalency/superiority; where well‐stratified cohort designs are likely preferred. Large numbers of independent cohort studies support the use of CAD/CAM ceramic inlay/onlay restorations and crowns but many complications inhibit the application of high‐level systematic review. Except perhaps for fiber‐based endodontic posts, the clinical FRC literature appears insufficient for expert review. Single in vitro measures cannot currently serve as evidence for clinical practice, except in limited cases of simple function (e.g., impression material accuracy). Batteries of in vitro measures are often applied during materials development but cannot substitute for clinical study.  相似文献   
953.
Sawatzky B, Denison I, Langrish S, Richardson S, Hiller K, Slobogean B. The Segway Personal Transporter as an alternative mobility device for people with disabilities: a pilot study.

Objectives

To determine the functional measures that best correlate with the skill levels of people with disabilities who operate a Segway Personal Transporter, and—using a qualitative analysis—to explore subjects’ experience with the Segway.

Design

A prospective study encompassing 3 training sessions with the Segway to correlate subjects’ functional ability (eg, cognition, balance, mobility, muscle strength) with their skill level on the device.

Setting

A provincial adult rehabilitation center.

Participants

Twenty-three subjects (age range, 19−65y) with a wide range of disabilities (eg, multiple sclerosis, spinal cord injury, amputation) who could walk at least 6m with or without assistance.

Interventions

Not applicable.

Main Outcome Measures

Segway Task Assessment, Berg Balance Scale, and Timed Up & Go test.

Results

No correlation was found because all participants successfully completed the final Segway Task Assessment, regardless of scores on functional assessments.

Conclusions

The Segway is a useful device for a broad range of populations with functional disabilities. Subjects found the Segway easy to use and were excited about its potential as an assistive device for use in their communities.  相似文献   
954.
Components of the renin-angiotensin system (RAS) are expressed in a number of areas in the brain involved in cardiovascular control. However, it has been difficult to link RAS actions in circumscribed brain regions to specific physiological functions. In a study appearing in this issue of the JCI, Sakai and associates use a combination of sophisticated transgenic techniques and stereotaxic microinjection of recombinant viral vectors to demonstrate a pivotal role in the regulation of thirst and salt appetite of angiotensin II generated in the subfornical organ in the brain (see the related article beginning on page 1088).  相似文献   
955.
956.
957.
We report a case of biventricular implantable cardioverter-defibrillator (ICD) insertion in which standard lead placement techniques could not achieve left ventricular capture. Protrusion of the guidewire beyond a venous stenosis provided adequate left ventricular capture.  相似文献   
958.
959.
Physician and nurse satisfaction with an Electronic Medical Record system   总被引:2,自引:0,他引:2  
Electronic Medical Records (EMRs) are intended to support clinical activity, improve efficiency, and reduce error. Reluctance to use EMRs may exist among clinicians. The purpose of this study was to assess physician and nurse satisfaction with an Emergency Department (ED) EMR. We surveyed Emergency Medicine (EM) physicians and nurses at a large urban teaching hospital after implementation of an Emergency Department EMR. The questionnaire assessed: 1) computer background and experience; 2) perceptions regarding EMR use; and 3) concerns about impact upon quality of patient care. The clinicians find the EMR easy to use and are generally satisfied with the impact on their work. However, they report that the EMR has no positive impact on patient care. They report confusion in following the sequence of screens, and are concerned with the amount of time it takes to use the EMR and the confidentiality of patient information. Similar results were found between physicians and nurses. Nurses, but not physicians, report that they are able to finish work much faster than before implementation (p < 0.05). We were unable to correlate computer background and experience with satisfaction with an EMR. This survey suggests that EM physicians and nurses favor the use of an EMR and suggests opportunities for EMR enhancement.  相似文献   
960.

Background

Capillary lymphatic venous malformations (CLVM) and associated syndromes, including Klippel–Trenaunay syndrome (KTS) and congenital lipomatous overgrowth, vascular malformation, epidermal nevi, skeletal, and spinal syndrome (CLOVES), are underrecognized disorders associated with high morbidity from chronic pain, recurrent infections, bleeding, and clotting complications. The rarity of these disorders and heterogeneity of clinical presentations make large-scale randomized clinical drug trials challenging. Identification of PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha [gene]) mutations in CLVM has made targeted medications, such as sirolimus, attractive treatment options. The aim of this study was to investigate the safety and efficacy of sirolimus therapy in CLVM.

Procedure

A combined prospective and retrospective cohort of pediatric and young adult patients with CLVM treated with sirolimus was evaluated for disease response, including symptom improvement, quality of life (QOL), and radiologic response. Sirolimus dosing regimens and toxicities were also assessed.

Results

Twenty-nine patients with CLVM, including KTS and CLOVES, were included. Ninety-three percent of patients reported improved QOL, and 86% had improvement in at least one symptom. Most significantly, improvement was noted in 100% of patients with bleeding and 89% with thrombotic complications with corresponding decreases in mean D-dimer (p = .008) and increases in mean fibrinogen (p = .016). No patients had progressive disease on sirolimus. Most common side effects included neutropenia, lymphopenia, infection, and aphthous ulcers/stomatitis. No toxicities were life-threatening, and none required long-term discontinuation of sirolimus.

Conclusion

Sirolimus appears to be effective at reducing complications and improving QOL in patients with CLVM and associated syndromes. In this patient cohort, sirolimus was well tolerated and resulted in few treatment-related toxicities.  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