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   104729篇
  免费   8491篇
  国内免费   3016篇
耳鼻咽喉   668篇
儿科学   1535篇
妇产科学   1146篇
基础医学   20376篇
口腔科学   2658篇
临床医学   6376篇
内科学   14939篇
皮肤病学   1902篇
神经病学   9891篇
特种医学   2538篇
外国民族医学   29篇
外科学   7667篇
综合类   11663篇
现状与发展   13篇
预防医学   4149篇
眼科学   1048篇
药学   15667篇
  60篇
中国医学   4546篇
肿瘤学   9365篇
  2024年   1106篇
  2023年   2082篇
  2022年   4006篇
  2021年   4518篇
  2020年   4038篇
  2019年   4154篇
  2018年   3869篇
  2017年   3958篇
  2016年   3590篇
  2015年   4118篇
  2014年   6003篇
  2013年   6394篇
  2012年   5623篇
  2011年   6792篇
  2010年   5358篇
  2009年   5514篇
  2008年   5316篇
  2007年   4631篇
  2006年   4074篇
  2005年   3650篇
  2004年   3222篇
  2003年   2826篇
  2002年   2174篇
  2001年   1746篇
  2000年   1527篇
  1999年   1366篇
  1998年   1350篇
  1997年   1289篇
  1996年   1203篇
  1995年   1093篇
  1994年   993篇
  1993年   912篇
  1992年   744篇
  1991年   626篇
  1990年   539篇
  1989年   432篇
  1988年   405篇
  1987年   396篇
  1986年   474篇
  1985年   657篇
  1984年   636篇
  1983年   481篇
  1982年   462篇
  1981年   395篇
  1980年   360篇
  1979年   305篇
  1978年   194篇
  1977年   151篇
  1976年   155篇
  1975年   99篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Blood pressure regulation is impacted by a spinal cord injury (SCI) due to impaired descending sympathetic vascular control. Common blood pressure problems in the SCI population include persistently low blood pressure with bouts of orthostatic hypotension and autonomic dysreflexia, which are more prevalent in individuals with lesions above the sixth thoracic vertebral level; however, they may occur regardless of the neurological level of injury. Although blood pressure disorders adversely impact daily function and quality of life, most individuals with SCI do not acknowledge this association. Few pharmacological options have been rigorously tested for safety and efficacy to manage blood pressure disorders in the SCI population. Furthermore, clinical management of any one blood pressure disorder may adversely impact others, as such treatment is complicated and not often prioritized.  相似文献   
2.
《Neuro-Chirurgie》2023,69(5):101478
ObjectivePituitary abscess is an often misdiagnosed, rare clinical disorder. To improve diagnostic accuracy and the efficacy of surgical and antibiotic therapy for patients with pituitary abscess, herein, we retrospectively reviewed 15 patients who presented with pituitary abscesses from 2005 to 2022.DesignRetrospective study.PatientsFifteen patients underwent transsphenoidal surgery and received antibiotic treatment.MeasurementsComplete details regarding medical history, clinical manifestations, laboratory examinations, imaging studies, and treatment strategies were obtained for all patients.ResultsMost patients presented with hypopituitarism and headaches, while some presented with fever, visual disturbances, and diabetes insipidus (DI). Abscesses showed significant annular enhancement post gadolinium injection. In most patients, pituitary abscess can be cured via microscopic or endoscopic drainage of the abscess followed by antibiotic treatment. Complete cure of pituitary abscess was observed in nine patients, with six cases of prolonged hypopituitarism and only one case of recurrence. Long-term hormone replacement therapy was effective in the postoperative management of hypopituitarism.ConclusionsThe typical manifestations of pituitary abscess include hypopituitarism and headaches; the presence of an enhanced ring at the edge of the mass on contrast-enhanced magnetic resonance images (MRI) is highly suggestive of pituitary abscess. We recommend antibiotic treatment for 4–6 weeks postoperatively, based on the results of bacterial cultures or metagenomic next-generation sequencing (mNGS).  相似文献   
3.
Our knowledge of the radiological spectrum of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is growing rapidly. An update on the radiological features of the disease, and its evolution is thus necessary. Magnetic resonance imaging (MRI) has an increasingly important role in the differential diagnosis of MOGAD particularly from aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and multiple sclerosis (MS). Differentiating these conditions is of prime importance because the management is different between the three inflammatory diseases, and thus could prevent further attack-related disability. Therefore, identifying the MRI features suggestive of MOGAD has diagnostic and prognostic implications. We herein review optic nerve, spinal cord and the brain MRI findings from MOGAD adult patients, and compare them to AQP4-NMOSD and MS.  相似文献   
4.
《Radiography》2022,28(3):746-750
IntroductionIn response to advice from The National Institute for Health and Care Excellence (1) to reduce hospital visits during COVID-19, standard headrests were introduced for head and neck radiotherapy within Northern Centre for Cancer Care (NCCC). The standard headrest requires one mould room appointment compared to 3 appointments with customised headrests.MethodsTwo groups of 10 patients treated between December 2019 and June 2020 were retrospectively analysed by 1 observer. Groups were stratified according to age, sex and tumour site. One group had customised headrest and the other had standard headrest. Five hundred and forty seven cone beam computed tomography images were reviewed. A 6 Degree of Freedom match was performed then chin, shoulder and spine position were assessed using dosimetrist drawn structures. Structures out of the tolerance were recorded. A chi-squared test was used for statistical analysis.ResultsThe out of tolerance chin position count recorded was 21 for customised headrest and 36 for standard headrest, p-value 0.046. The shoulder position count was 13 for customised headrest and 77 for standard headrest p-value <0.001. The spine position count was 3 for CHR and 21 for standard headrest, p-value <0.001. This means the headrests compared are not equivalent in terms of set up reproducibility. Overall the standard headrest group had 10 set-up re-scans and no set up re-scans were recorded in the customised headrest group.ConclusionFewer hospital visits with SHR reduce patient exposure to COVID-19. However, CHR provided a more reliable level of immobilisation in this study.Implications for practiceThe radiotherapy service will be reviewed in line with these findings.  相似文献   
5.
《Immunity》2022,55(3):475-493.e5
  1. Download : Download high-res image (123KB)
  2. Download : Download full-size image
  相似文献   
6.
《Injury》2023,54(2):318-328
PurposeThis study intended to determine the properties of induced membranes after various periods of polymethyl methacrylate (PMMA) retention and the effect of different retention intervals on subsequent defect repair.MethodsModel of a critical bone defect in rabbits was prepared to obtain the induced membrane. For varying intervals of spacer insertion (2, 4, 6, 8, 12, 16, and 20 weeks postoperatively), angiogenesis, osteogenesis, and MSC-related properties were analyzed by immunohistochemistry and western-blot. Furthermore, 2, 4, 6, and 8 weeks after PMMA insertion, bone grafting was performed. Characteristics of defect repair were analyzed by X-ray and micro-CT analysis.ResultsThe induced membrane displayed angiogenesis, osteogenesis, and MSC-related properties from the 2- to 20-week intervals. Quantitation of protein expression (RUNX2, ALP, VEGF, TGF-beta, OCT4, and STRO1) revealed that selected proteins gradually rose to a high level at 4–8 weeks postoperatively and then decreased to a low level over a long time period. Following bone grafting, the most new bone formation was in the group when grafting was performed at 4 weeks, followed by the groups at 2 and 6 weeks, with the least in the group at 8 weeks.ConclusionThe induced membrane displays angiogenesis, osteogenesis, and MSC-related properties from the 2- to 20-week intervals. These were increased to a peak level at 4–8 weeks postoperatively and then gradually decreased. The optimal timing for bone grafting at the second stage in the presented model was 4 weeks after PMMA insertion.  相似文献   
7.
8.
9.

Objectives

The aim of this study was to develop a high-fidelity minimally invasive mitral valve surgery (MIMVS) simulator.

Methods

The process of industrial serial design was applied based on pre-set requirements, acquired by interviewing experienced mitral surgeons. A thoracic torso with endoscopic and robotic access and disposable silicone mitral valve apparatus with a feedback system was developed. The feedback system was based on 4 cameras around the silicone valve and an edge detection algorithm to calculate suture depth and width. Validity of simulator measurements was assessed by comparing simulator-generated values with measurements done manually on 3-dimensional reconstructed micro-computed tomography scan of the same sutures. Independent surgeons tested the simulator between 2014 and 2018, whereupon an evaluation was done through a questionnaire.

Results

The feedback system was able to provide width and depth measurements, which were subsequently scored by comparison to pre-set target values. Depth did not significantly differ between simulator and micro-computed tomography scan measurements (P = .139). Width differed significantly (P = .001), whereupon a significant regression equation was found (P < .0001) to calibrate the simulator. After calibration, no significant difference was found (P = .865). In total, 99 surgeons tested the simulator and more than agreed with the statements that the simulator is a good method for training MIMVS, and that the mitral valve and suture placement looked and felt realistic.

Conclusions

We successfully developed a high-fidelity MIMVS simulator for endoscopic and robotic approaches. The simulator provides a platform to train skills in an objective and reproducible manner. Future studies are needed to provide evidence for its application in training surgeons.  相似文献   
10.

Background

Catheter ablation of ventricular tachycardia (VT) can reduce the burden of ventricular arrhythmia (VA) but its effect on health care utilization and costs after such therapy is poorly known. We sought to compare the rates of cardiovascular (CV)-related hospitalizations, survival, and health care costs in patients with recurrent VT treated either with VT ablation or with medical therapy.

Methods

One-hundred implantable cardioverter-defibrillator patients with structural heart disease who underwent VT ablation were included. Propensity score-matched patients with recurrent VT treated with medical therapy were identified from a prospective registry of approximately 7000 de novo implantable cardioverter-defibrillator patients. Outcomes and costs were ascertained using health administrative databases.

Results

Among patients who underwent VT ablation, the cumulative rates of VA-related hospitalizations were lower in the 2 years after their ablation procedure compared with the year before (rate ratio, 0.3; 95% confidence interval [CI], 0.22-0.43). Rates of CV-related hospitalization and hospitalization because of VA post index date were similar between the VT ablation and medical therapy groups (hazard ratio [HR], 0.94; 95% CI, 0.57-1.54 and HR, 1.04; 95% CI, 0.57-1.91, respectively). Health care costs in the VT ablation patients were not increased post-ablation compared with the medical management group. The risk of all-cause mortality was lower among patients in the VT ablation group relative to the medical therapy group (HR, 0.64; 95% CI, 0.4-0.99).

Conclusions

Patients who underwent VT ablation experienced a significant reduction in their rate of VA-related hospitalizations. Patients treated with VT ablation had similar rates of CV-related hospitalization compared with those treated with medical therapy without increased health care-related costs.  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