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   374298篇
  免费   22784篇
  国内免费   8209篇
耳鼻咽喉   4678篇
儿科学   13753篇
妇产科学   6103篇
基础医学   28132篇
口腔科学   8203篇
临床医学   41083篇
内科学   64843篇
皮肤病学   6412篇
神经病学   18989篇
特种医学   17896篇
外国民族医学   22篇
外科学   56794篇
综合类   36773篇
现状与发展   28篇
一般理论   51篇
预防医学   36531篇
眼科学   6646篇
药学   32140篇
  394篇
中国医学   11399篇
肿瘤学   14421篇
  2023年   5723篇
  2022年   8667篇
  2021年   16190篇
  2020年   11910篇
  2019年   19393篇
  2018年   14836篇
  2017年   10872篇
  2016年   10505篇
  2015年   13767篇
  2014年   25229篇
  2013年   22289篇
  2012年   24356篇
  2011年   23972篇
  2010年   19576篇
  2009年   18660篇
  2008年   17609篇
  2007年   16991篇
  2006年   14412篇
  2005年   10504篇
  2004年   6667篇
  2003年   5332篇
  2002年   4919篇
  2001年   4541篇
  2000年   5142篇
  1999年   4670篇
  1998年   4770篇
  1997年   3619篇
  1996年   2766篇
  1995年   2362篇
  1994年   2312篇
  1993年   1673篇
  1992年   1950篇
  1991年   1660篇
  1990年   1710篇
  1989年   1468篇
  1988年   1470篇
  1987年   1189篇
  1985年   4091篇
  1984年   5470篇
  1983年   3983篇
  1982年   4020篇
  1981年   3819篇
  1980年   3378篇
  1979年   3081篇
  1978年   2475篇
  1977年   2196篇
  1976年   2276篇
  1975年   1800篇
  1974年   1673篇
  1973年   1577篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
《Enfermería clínica》2022,32(3):171-183
IntroductionAgeing is a period of physical and psychological changes. Inactivity is one of the biggest problems among the older adult population increasing the risk of sarcopenia and chronic diseases. Physical activity is an effective intervention to improve health outcomes. In recent years, there has been an increase in the use of technology, with health technology tools (ICT) appearing as an intervention to increase physical activity and improve associated health problems.ObjectiveIn this review, we evaluated the effectiveness of health technology to increase physical activity and to improve cardiovascular parameters in older adults.MethodologyStudies with a great variety of health technology tools to increase physical activity levels, and that evaluated the effect of that increase on cardiovascular parameters were included by searching the main databases.ResultsEleven studies reporting the use of a variety of ICT tools were included in this review. Despite these differences, the effectiveness of health technology tool interventions has been demonstrated in increasing physical activity and reducing cardiovascular parameters.DiscussionThe lack of adherence of older adults to health technology would be a disadvantage, but it has been shown that younger older adults are more familiar with health technology tools and the number using them is increasing.ConclusionHealth technology tools show effectiveness in increasing physical activity in older adults and improving cardiovascular parameters.  相似文献   
22.
《Vaccine》2022,40(19):2679-2695
Vaccinations are essential for preventing infectious diseases in children with chronic diseases as they have increased risk of infection from frequent use of biologics. Response to immunizations in this group is not well known.ObjectiveA systematic review was performed to evaluate three primary outcomes: efficacy; immunogenicity; and safety of vaccines in children with chronic conditions treated with biologics.MethodsThe protocol for our systematic review and meta-analysis was registered and published with PROSPERO. We searched electronic bibliographic databases for studies published from 2009 to 2019, focusing on vaccinations in children with chronic conditions treated with biologics.ResultsWe retrieved 532 records. Thirty-one full-text articles were selected, and 14 were included in the meta-analysis. No significant publication bias was found. Efficacy: limited data are available regarding the efficacy of vaccination, as most studies have focused on immunogenicity as surrogate outcome for efficacy. Immunogenicity: patients receiving anti-TNF-alpha therapy had a statistically significant risk of poor seroconversion (p = 0.028) and seroprotection by the serotype B influenza vaccine [inflammatory bowel disease (IBD) p = 0.013; juvenile idiopathic arthritis (JIA) p = 0.004]. We found adequate responses with H1N1 and H3N2 serotypes. Few studies existed for pneumococcal, hepatitis A virus, hepatitis B virus, varicella-zoster virus, Measles Mumps Rubella virus, and multiple vaccine administration. Safety: vaccine administration was not associated with serious side effects, but JIA patients on anti-TNF alpha therapy had a statistically significant risk of presenting with myalgia or arthralgia postinfluenza vaccine (p = 0.014).ConclusionsMore evidence concerning efficacy, immunogenicity, and safety of vaccinations is needed to guide physicians in the vaccine decision process for this pediatric population.  相似文献   
23.
24.
An ovine iliac vein thrombosis model was devised to test a wall-contacting rotational thrombectomy device. Thrombosis was successfully induced in 9 sheep with an average clot length of 31 mm ± 12 and >60% vessel occlusion on angiography. The thrombus was subsequently removed, maintaining normal intraoperative pulmonary arterial pressure (5.9 mm Hg ± 3.6) and complete distal reperfusion after thrombectomy. Additionally, the sheep were without signs of vascular trauma or embolic complications on gross necropsy and histopathologic analysis. The findings from this study support the use of an ovine iliac deep vein thrombosis model for testing of a lower extremity thrombectomy device.  相似文献   
25.
PurposeTo study, from a U.S. payer’s perspective, the economic consequences of drug-coated balloon (DCB) versus standard percutaneous transluminal angioplasty (PTA) use for the treatment of stenotic lesions in dysfunctional hemodialysis arteriovenous fistulae.Materials and MethodsCost differences between DCBs and PTA at year 1 and beyond were calculated via 2 methods. The first approach used the mean absolute number of trial-observed access circuit reinterventions through 12 months (0.65 ± 1.05 vs 1.05 ± 1.18 events per patient for DCBs and PTA, respectively) and projected treatment outcomes to 3 years. The second approach was based on the trial-observed access circuit primary patency rates at 12 months (53.8% vs 32.4%) and calculated the cost difference on the basis of previously published Medicare cost for patients who maintained or did not maintain primary patency. Assumptions regarding DCB device prices were tested in sensitivity analyses, and the numbers needed to treat were calculated.ResultsUsing the absolute number of access circuit reinterventions approach, the DCB strategy resulted in an estimated per-patient savings of $1,632 at 1 year and $4,263 at 3 years before considering the DCB device cost. The access circuit primary patency approach was associated with a per-patient cost savings of $2,152 at 1 year and $3,894 at 2.5 years of follow-up. At the theoretical DCB device reimbursement of $1,800, savings were $1,680 and $2,049 at 2.5 and 3 years, respectively. The one-year NNT of DCB compared to PTA was 2.48.ConclusionsEndovascular therapy for arteriovenous access stenosis with the IN.PACT AV DCB can be expected to be cost-saving if longer follow-up data confirm its clinical effectiveness.  相似文献   
26.
This study investigated the role of dual-energy computed tomography (CT) for lesion characterization in patients with peripheral arterial disease manifesting with chronic total occlusions (CTOs). Forty-one symptomatic patients with CTOs underwent dual-energy CT angiography before endovascular treatment. The lesions were subsequently analyzed in a dedicated workstation, and 2 indexes—dual-energy index (DEI) and effective Z (Zeff)—were calculated, ranging from 0.0027 to 0.321 and from 6.89 to 13.02, respectively. Statistical analysis showed a significant correlation between the DEI and Zeff values (P < .001). The interobserver intraclass correlation coefficient was 0.91 for the mean Zeff values and 0.86 for the mean DEI values. This technique could potentially provide useful information regarding the composition of a CTO.  相似文献   
27.
《Radiography》2022,28(2):353-359
Patient contact shielding has been in use for many years in radiology departments in order to reduce the effects and risks of ionising radiation on certain organs. New technologies in projection imaging and CT scanning such as digital receptors and automatic exposure control (AEC) systems have reduced doses and improved image consistency. These changes and a greater understanding of both the benefits and the risks from the use of shielding have led to a review of shielding use in radiology. A number of professional bodies have already issued guidance in this regard. This paper represents the current consensus view of the main bodies involved in radiation safety and imaging in Europe: European Federation of Organisations for Medical Physics, European Federation of Radiographer Societies, European Society of Radiology, European Society of Paediatric Radiology, EuroSafe Imaging, European Radiation Dosimetry Group (EURADOS), and European Academy of DentoMaxilloFacial Radiology (EADMFR). It is based on the expert recommendations of the Gonad and Patient Shielding (GAPS) Group formed with the purpose of developing consensus in this area. The recommendations are intended to be clear and easy to use. They are intended as guidance, and they are developed using a multidisciplinary team approach. It is recognised that regulations, custom and practice vary widely on the use of patient shielding in Europe and it is hoped that these recommendations will inform a change management program that will benefit patients and staff.  相似文献   
28.
《Genetics in medicine》2022,24(9):1814-1820
Although still in the early stages of development, the advent of fast, high-output, and cost-effective next-generation DNA sequencing technology is moving precision medicine into public health. Before this shift toward next-generation sequencing in public health settings, individual patients met geneticists after showing symptoms and through limited family screening. In the new era of precision public health, everyone is a possible participant in genetic sequencing, simply by being born (newborn screening), by donating blood (biobanking), or through population screening. These initiatives are increasingly offered to individuals throughout their life and more individuals are encountering opportunities to use DNA sequencing. This article raises awareness of these growing areas and calls for different models of public engagement and communication about genomics, including screening asymptomatic populations, obtaining consent for unspecified and unforeseen future uses of genomic data, and managing variants of uncertain significance. Given that such communication challenges loom large, established norms of practice in genomic medicine and research should be reconsidered.  相似文献   
29.
ObjectiveTo identify how individuals respond to unilateral upper extremity peripheral nerve injury via compensation (increased use of the nondominant hand). We hypothesized that injury to the dominant hand would have a greater effect on hand use (left vs right choices). We also hypothesized that compensation would not depend on current (postinjury) nondominant hand performance because many patients undergo rehabilitation that is not designed to alter hand use.DesignObservational survey, single-arm.SettingsAcademic research institution and referral center.ParticipantsA total of 48 adults (N=48) with unilateral upper extremity peripheral nerve injury. Another 14 declined participation. Referred sample, including all eligible patients from 16 months at 1 nerve injury clinic and 1 hand therapy clinic.InterventionsNot applicable.Main Outcome MeasuresHand use (% of actions with each hand) via Block Building Task. Dexterity via Jebsen-Taylor Hand Function.ResultsParticipants preferred their dominant hand regardless of whether it was injured: hand usage (dominant/nondominant) did not differ from typical adults, regardless of injured side (P>.07), even though most participants (77%) were more dexterous with their uninjured nondominant hand (mean asymmetry index, ?0.16±0.25). The Block Building Task was sensitive to hand dominance (P=2 × 10?4) and moderately correlated with Motor Activity Log amount scores (r2=0.33, P<.0001). Compensation was associated only with dominant hand dexterity (P=3.9 × 10?3), not on nondominant hand dexterity, rehabilitation, or other patient and/or injury factors (P>.1).ConclusionsPatients with peripheral nerve injury with dominant hand injury do not compensate with their unaffected nondominant hand, even if it is more dexterous. For the subset of patients unlikely to recover function with the injured hand, they could benefit from rehabilitation that encourages compensation with the nondominant hand.  相似文献   
30.
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