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   5491篇
  免费   281篇
  国内免费   36篇
耳鼻咽喉   28篇
儿科学   284篇
妇产科学   100篇
基础医学   295篇
口腔科学   101篇
临床医学   825篇
内科学   1073篇
皮肤病学   100篇
神经病学   428篇
特种医学   171篇
外科学   509篇
综合类   312篇
预防医学   797篇
眼科学   90篇
药学   378篇
中国医学   101篇
肿瘤学   216篇
  2024年   2篇
  2023年   209篇
  2022年   294篇
  2021年   441篇
  2020年   383篇
  2019年   473篇
  2018年   396篇
  2017年   246篇
  2016年   148篇
  2015年   160篇
  2014年   436篇
  2013年   419篇
  2012年   253篇
  2011年   320篇
  2010年   235篇
  2009年   272篇
  2008年   225篇
  2007年   206篇
  2006年   117篇
  2005年   102篇
  2004年   89篇
  2003年   54篇
  2002年   28篇
  2001年   40篇
  2000年   30篇
  1999年   29篇
  1998年   23篇
  1997年   22篇
  1996年   11篇
  1995年   13篇
  1994年   9篇
  1993年   7篇
  1992年   10篇
  1991年   5篇
  1990年   3篇
  1989年   5篇
  1987年   3篇
  1985年   17篇
  1984年   9篇
  1983年   10篇
  1982年   13篇
  1981年   11篇
  1980年   9篇
  1979年   5篇
  1978年   1篇
  1977年   2篇
  1976年   3篇
  1975年   4篇
  1974年   3篇
  1973年   1篇
排序方式: 共有5808条查询结果,搜索用时 15 毫秒
61.
Echography is the most appropriate imaging modality for investigating astronauts. Unfortunately, it requires a great deal of training to perform ultrasound examinations, which can be difficult and time consuming, especially if the astronaut does not have a medical background. We designed a new echography system with motorized probes that allows for the majority of exam functions to be controlled by a ground-based sonographer. Using tele-operation, the sonographer controls the orientation of the transducer (tilt, rotation) and echograph settings (gain, depth, freeze) and triggers ultrasound functions (pulsed wave color Doppler, 3-D capture, radiofrequency data collection, elastography). With this system, astronauts are required to hold the motorized probe only at the locations indicated, with the remainder of the exam being conducted by the ground-based sonographer. During spaceflight, ultrasound imaging of the carotid artery, jugular vein, thyroid, liver, gallbladder, biliary tract and portal vein (2-D, 3-D, color, pulsed wave, radiofrequency) were successfully performed.  相似文献   
62.
Autoimmune hepatitis (AIH) is a severe liver disease affecting all age groups worldwide. Novel basic and clinical aspects of AIH, addressed at a Monothematic Conference in London in September 2015, are highlighted in this review. The diagnosis of AIH relies upon detection of characteristic autoantibodies, hypergammaglobulinemia, and interface hepatitis on liver histology. The International Autoimmune Hepatitis Group (IAIHG) has devised diagnostic scoring systems to help in comparative studies and clinical practice. AIH arises in a genetically predisposed host, when yet unknown triggers – such an encounter with a pathogen – lead to a T cell-mediated immune response targeting liver autoantigens. This immune response is inadequately controlled because regulatory mechanisms are impaired. The mainstay of treatment for AIH is immunosuppression, which should be instituted as soon as the diagnosis is made. Standard treatment regimens include relatively high doses of predniso(lo)ne, which are tapered gradually as azathioprine is introduced. Recent guidelines have described newer treatment regimens and have tightened the goal of therapy to complete normalization of biochemical, serological and histological parameters. Mycophenolate mofetil, calcineurin inhibitors, mTOR inhibitors and biological agents are potential salvage therapies, but should be reserved for selected non-responsive patients and administered only in experienced centers. Liver transplantation is a life-saving option for those patients who progress to end-stage liver disease. Further dissection of cellular and molecular pathways involved in AIH pathogenesis is likely to lead to the discovery of novel, tailored and better tolerated therapies.  相似文献   
63.
Stabilometry is a useful tool for examining patients with functional disorders of the vestibular system. However, measurement techniques and devices vary by country. Therefore, international standardization of stabilometry is mandatory to validate the exchange of important findings. This was advocated at the 1983 Posturography Meeting in Kyoto but has not been adopted worldwide, and each country has continued to use unique regional measurement methods. In Japan, stabilometry has widespread application in medical practice in conjunction with research into its applications. With a goal of international standardization, we present details of stabilometry measurement methods and their application in Japan, together with a brief history and potential future directions of stabilometry.  相似文献   
64.
General practitioners (GPs) are frontline health workers. They should be sensitive to the health needs of the community in addition to caring for patients that visit their practice. Due to changes in demography, epidemiology, ecology and healthcare policy, a community orientation becomes more important. Our research question is: to what extent does community orientation of GPs vary between countries and GPs and how can this variation be explained? We use cross-sectional survey data from the QUALICOPC study, conducted among over 7000 GPs in 34 countries. Community orientation was measured through a scale constructed from three survey questions on whether GPs would take action when confronted with: repeated accidents in an industrial setting, frequent respiratory problems in patients living near a certain industry, and repeated cases of food poisoning in the local community. Independent variables are at healthcare system level and GP or practice level. Data were analysed using linear multilevel regression analysis. Community orientation varies between GPs and countries. Community orientation is more frequent in healthcare systems with a list system, among self-employed GPs, those using medical records to make overviews, and those more active in prevention and multidisciplinary cooperation. GPs in rural areas and areas with more people from ethnic minorities are more community oriented. Based on the variation between countries and GPs, we would like to raise awareness and underline the importance of multidisciplinary cooperation.  相似文献   
65.
BackgroundJoint contractures are frequent conditions in individuals in geriatric care settings and are associated with activity limitations and participation restrictions. As such, relevant intervention programs should address these aspects, and the effectiveness of such programs should be determined by assessing improvement in activities and participation. However, no patient-centred and psychometrically sound outcome measures for this purpose are available so far.ObjectivesThe objectives of this study were to develop and to validate a new outcome measure, the PaArticular Scales, to quantify activities and participation in older individuals with joint contractures. Specific aims were (A) to operationalize the content of an International Classification of Functioning, Disability and Health-based standard set towards meaningful questions and to combine them to a questionnaire and (B) to assess the psychometric properties of the developed questionnaire, in detail to evaluate test–retest reliability, objectivity, internal consistency reliability and criterion validity.DesignOperationalization was reached by an expert consensus conference and a subsequent expert Delphi survey. Psychometric properties were assessed in a cross-sectional study.SettingsNursing homes, geriatric rehabilitation facilities.Participants23 experts (nurses, physicians, physical and occupational therapists) participated in the consensus conference and the Delphi survey. A total of 191 individuals with joint contractures (as confirmed by physician, nurse or physical therapist) between 65 and 102 years, living in nursing homes or as patients in geriatric rehabilitation were enrolled in the cross-sectional study.MethodsRasch Partial Credit Modelling.ResultsThe consensus conference and Delphi survey resulted in a questionnaire with 86 items of the International Classification of Functioning, Disability and Health. Test–retest-reliability among those was acceptable (Cohen's weighted kappa: 0.779). The Rasch analysis revealed two independent interval-scaled scales with 24 items for the Activities scale and 11 items for the Participation scale with high internal consistency reliability. Cronbach's alpha was 0.96 for the Activities scale and 0.92 for the Participation scale. Criterion validity was −0.40 and −0.30 for the Activities scale and for the Participation scale, respectively.ConclusionsThe PaArticular Scales, a new patient-centred and psychometric sound outcome measures to comprehensively assess the impact of joint contractures in geriatric care, are available now. These developed scales will serve as primary outcomes in a scheduled evaluation of a complex intervention to improve participation and quality of life in nursing home residents with joint contractures.  相似文献   
66.
67.
Background and aimsEfficient analysis strategies for complex network with cardiovascular disease (CVD) risk stratification remain lacking. We sought to identify an optimized model to study CVD prognosis using survival conditional inference tree (SCTREE), a machine-learning method.Methods and resultsWe identified 5379 new onset CVD from 2006 (baseline) to May, 2017 in the Kailuan I study including 101,510 participants (the training dataset). The second cohort composing 1,287 CVD survivors was used to validate the algorithm (the Kailuan II study, n = 57,511). All variables (e.g., age, sex, family history of CVD, metabolic risk factors, renal function indexes, heart rate, atrial fibrillation, and high sensitivity C-reactive protein) were measured at baseline and biennially during the follow-up period. Up to December 2017, we documented 1,104 deaths after CVD in the Kailuan I study and 170 deaths in the Kailuan II study. Older age, hyperglycemia and proteinuria were identified by the SCTREE as main predictors of post-CVD mortality. CVD survivors in the high risk group (presence of 2–3 of these top risk factors), had higher mortality risk in the training dataset (hazard ratio (HR): 5.41; 95% confidence Interval (CI): 4.49–6.52) and in the validation dataset (HR: 6.04; 95%CI: 3.59–10.2), than those in the lowest risk group (presence of 0–1 of these factors).ConclusionOlder age, hyperglycemia and proteinuria were the main predictors of post-CVD mortality.Trial registrationChiCTR-TNRC-11001489.  相似文献   
68.
目的通过参加IAEA/WHO组织的TLD国际比对,检查二级标准剂量学实验室(SSDL)放疗水平剂量标准和国际标准的一致性。方法 SSDL对IAEA邮寄的TLD进行照射,并计算出其吸收剂量,然后将TLD及其计算结果寄往IAEA剂量学实验室,IAEA对其进行评价后给出比对的偏差。结果本次60Coγ射线吸收剂量比对的偏差为-1.8%。结论按照IAEA要求,该项比对的最大允许偏差为±3.5%,所以这次比对结果是合格的。  相似文献   
69.
BackgroundOpen pelvic fractures are rare injuries, associated with high patient morbidity and mortality. Few studies have investigated the impact of patient demographics, comorbidities, and injury related factors on complication and mortality rates. The purpose of this study was to: (1) identify the overall incidence of complications and mortality after open pelvic fractures, (2) compare patient factors between those who did and did not develop complications, (3) identify perioperative independent risk factors for complications and mortality.MethodsA query was performed for patients with open pelvic fractures between 2007 and 2017 using the American College of Surgeons National Trauma Data Bank. Patient and injury specific variables were collected and complications were identified using International Classification of Disease Ninth and Tenth edition Codes. Patient demographic and perioperative data was compared using Fisher’s exact test and chi-square test for categorical variables, and Welch’s t-test for continuous variables. Using pooled data from multiple imputations, logistic regressions were used to calculate odds ratios and confidence intervals of independent risk factors for complications.ResultsA total of 19,834 open pelvic fracture cases were identified, with 9622 patients (48.5%) developing at least one complication. Patients who developed complications were older (35.0 vs 38.1 years), and had higher Injury Severity Scores (17.7 vs 26.5), lower Glasgow Coma Scores (14.2 vs 11.7), and a larger proportion presenting with hypotension (21% vs 6.9%). After pooled regression involving 19 factors, these were the strongest independent predictors of inpatient complication and mortality.ConclusionWe report a mortality rate of 14%, with an inclusive complication rate of 48.5%. Evaluating risk factors for morbidity and mortality for this devastating orthopaedic injury provides knowledge of an inherently sparse population.Level of EvidenceLevel II, Retrospective study.  相似文献   
70.
Background/ObjectiveOccurrence of post-dural puncture headache (PDPH) after diagnostic lumbar puncture (LP) for idiopathic intracranial hypertension (IIH) may seem very unlikely in clinical practice. Nevertheless, it has been suggested by several studies, mainly in sub-group analyses. We aimed to evaluate the prevalence of PDPH in an IIH population and determine any eventual predictive factors of PDPH occurrence.MethodsWe conducted a retrospective multiple-center observational study. All newly diagnosed IIH patients who met the International Classification of Headache Disorders (ICHD-3) or the Dandy modified criteria were included from three different French hospitals. They all underwent LP following the same process with the same type of needle. We recorded PDPH occurring within five days after LP, as defined by ICHD-3 criteria.ResultsSeventy-four IIH patients were recruited, of whom 23 (31%) presented with PDPH. Neither classical risk factors for PDPH such as body mass index, age or gender, nor cerebrospinal fluid opening pressure, or specific IIH features were associated with occurrence of PDPH.ConclusionPDPH can occur after LP in IIH patients. Clinicians should be aware of this possible event during the IIH diagnosis assessment and should not automatically reconsider IIH diagnosis. PDPH prevention using an atraumatic needle and dedicated PDPH treatment seem relevant in IIH patients.  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