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   75414篇
  免费   7097篇
  国内免费   3853篇
耳鼻咽喉   416篇
儿科学   1411篇
妇产科学   482篇
基础医学   6318篇
口腔科学   960篇
临床医学   11112篇
内科学   6587篇
皮肤病学   304篇
神经病学   8280篇
特种医学   4679篇
外国民族医学   3篇
外科学   14245篇
综合类   13776篇
现状与发展   3篇
一般理论   1篇
预防医学   5493篇
眼科学   993篇
药学   6688篇
  40篇
中国医学   3613篇
肿瘤学   960篇
  2024年   98篇
  2023年   1487篇
  2022年   1919篇
  2021年   3067篇
  2020年   2945篇
  2019年   2380篇
  2018年   2555篇
  2017年   2618篇
  2016年   3081篇
  2015年   3239篇
  2014年   5117篇
  2013年   5962篇
  2012年   4716篇
  2011年   4946篇
  2010年   4359篇
  2009年   4113篇
  2008年   3916篇
  2007年   3748篇
  2006年   3521篇
  2005年   3147篇
  2004年   2895篇
  2003年   2213篇
  2002年   1859篇
  2001年   1636篇
  2000年   1310篇
  1999年   1069篇
  1998年   992篇
  1997年   985篇
  1996年   863篇
  1995年   750篇
  1994年   751篇
  1993年   545篇
  1992年   528篇
  1991年   456篇
  1990年   423篇
  1989年   335篇
  1988年   302篇
  1987年   189篇
  1986年   213篇
  1985年   234篇
  1984年   166篇
  1983年   109篇
  1982年   157篇
  1981年   133篇
  1980年   93篇
  1979年   63篇
  1978年   43篇
  1977年   40篇
  1976年   32篇
  1975年   21篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
61.
PurposeContrast-induced acute kidney injury (CI-AKI) is a common and potentially serious complication of percutaneous coronary interventions (PCI). In this study, we tested the hypothesis whether serum and urinary hepcidin could represent early biomarkers of CI-AKI in patients with normal serum creatinine undergoing PCI. In addition, we assessed serum and urinary neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, eGFR and serum creatinine in these patients.MethodsSerum and urinary hepcidin and NGAL, serum cystatin C, were evaluated before, and after 2, 4, 8, 24 and 48 h after PCI using commercially available kits. Serum creatinine was assessed before, 24 and 48 h after PCI.ResultsWe found a significant rise in serum hepcidin as early as after 4 and 8 h when compared to the baseline values. Serum NGAL increased after 2, 4 and 8 h, and in urinary NGAL after 4, 8 and 24 h after PCI. We found a significant fall in urinary hepcidin after 8 and 24 h after PCI. Serum cystatin C increased significantly 8 h after PCI, reaching peak 24 h after PCI and then decreased after 48 h. The prevalence of CI-AKI was 8%. Urine hepcidin was significantly lower 8 and 24 h after PCI in patients with CI-AKI, while serum and urine NGAL were significantly higher in patients with CI-AKI.ConclusionsOur findings suggest that serum hepcidin might be an early predictive biomarker of ruling out CI-AKI after PCI, thereby contributing to early patient risk stratification. However, our data needs to be validated in large cohorts with various stages of CKD.  相似文献   
62.
63.
《Injury》2019,50(4):834-847
The use of suture associated with heterologous fibrin sealant has been highlighted for reconstruction after peripheral nerve injury, having the advantage of being safe for clinical use. In this study we compared the use of this sealant associated with reduced number of stitches with conventional suture after ischiatic nerve injury. 36 Wistar rats were divided into 4 groups: Control (C), Denervated (D), ischiatic nerve neurotmesis (6 mm gap); Suture (S), epineural anastomosis after 7 days from neurotmesis, Suture + Fibrin Sealant (SFS), anastomosis with only one suture point associated with Fibrin Sealant. Catwalk, electromyography, ischiatic and tibial nerve, soleus muscle morphological and morphometric analyses were performed. The amplitude and latency values of the Suture and Suture + Fibrin Sealant groups were similar and indicative of nerve regeneration.The ischiatic nerve morphometric analysis in the Suture + Fibrin Sealant showed superior values related to axons and nerve fibers area and diameter when compared to Suture group. In the Suture and Suture + Fibrin Sealant groups, there was an increase in muscle weight and in fast fibers frequency, it was a decrease in the percentage of collagen compared to group Denervated and in the neuromuscular junctions, the synaptic boutons were reestablished.The results suggest a protective effect at the lesion site caused by the fibrin sealant use. The stitches reduction minimizes the trauma caused by the needle and it accelerates the surgical practice. So the heterologous fibrin sealant use in nerve reconstruction should be considered.  相似文献   
64.
BackgroundImpaired self-awareness (ISA) has frequently been found to be both frequent and deleterious in patients with moderate to severe traumatic brain injury (TBI).ObjectivesThe present paper is the first of a two-part systematic review of ISA after traumatic brain injury (TBI), focusing on assessment methods, clinical aspects and recovery.MethodsFollowing the PRISMA guidelines, 95 articles meeting the inclusion criteria were included.ResultsISA occurs in 30% to 50% of patients with moderate to severe TBI, although it tends to improve with time. There is no one single gold-standard measure of ISA. Self-proxy discrepancy scores, with scales such as the Patient Competency Rating Scale or the Awareness Questionnaire, or a structured interview such as the Self Awareness of Deficits Interview, are the most frequently used assessment methods, with adequate psychometric properties. Scores on these different scales correlate only moderately with each other, which suggests that they may address different aspects of self-awareness. ISA mainly concerns cognitive and behavioral problems rather than physical or sensory impairments and may concern different areas of functioning, such as anticipatory, emergent or meta-cognitive awareness.ConclusionISA is a complex and multifaceted issue that should be systematically assessed in rehabilitation settings using a range of relatively well-validated tools. The consequences and predictors of ISA after TBI will be addressed in a companion paper.  相似文献   
65.
66.
BackgroundPatients with traumatic intracranial hemorrhage (TIH) frequently receive repeat head CT scans (RHCT) to assess for progression of TIH. The utility of this practice has been brought into question, with some studies suggesting that in the absence of progressive neurologic symptoms, the RHCT does not lead to clinical interventions.MethodsThis was a retrospective review of consecutive patients with CT-documented TIH and GCS ≥ 13 presenting to an academic emergency department from 2009 to 2013. Demographic, historical, and physical exam variables, number of CT scans during admission were collected with primary outcomes of: neurological decline, worsening findings on repeat CT scan, and the need for neurosurgical intervention.ResultsOf these 1126 patients with mild traumatic intracranial hemorrhage, 975 had RHCT. Of these, 54 (5.5% (4.2–7.2 95 CI) had neurological decline, 73 (7.5% 5.9–9.3 95 CI) had hemorrhage progression on repeat CT scan, and 58 (5.9% 4.5–7.6 95 CI) required neurosurgical intervention. Only 3 patients (0.3% 0.1–0.9% 95 CI) underwent neurosurgical intervention due to hemorrhage progression on repeat CT scan without neurological decline. In this scenario, the number of RHCT scans needed to be performed to identify this one patient is 305.ConclusionsRHCT after initial findings of TIH and GCS ≥ 13 leading to a change to operative management in the absence of neurologic progression is a rare event. A protocol that includes selective RHCT including larger subdural hematomas or patients with coagulopathy (vitamin K inhibitors and anti-platelet agents) may be a topic for further study.  相似文献   
67.
68.
Objective: The purpose was to describe the prevalence and characteristics of healthcare utilization among individuals with spinal cord injury (SCI) from a Level I trauma center.

Design: Retrospective data analysis utilizing a local acute trauma registry for initial hospitalization and merged with the Dallas-Fort Worth Hospital Council registry to obtain subsequent health care utilization in the first post-injury year.

Setting: Dallas, TX, USA.

Participants: Six hundred and sixty four patients were admitted with an acute traumatic SCI from January 2003 through June 2014 to a Level I trauma center. Fifty five patients that expired during initial hospitalization and 18 patients with unspecified SCI (defined by ICD-9 with no etiology or level of injury specified) were not included in the analysis, leaving a final sample of 591.

Outcome Measures: Data included demographic and clinical characteristics, charges, and healthcare utilization.

Results: Mean age was 46.1?years (±18.9?years), the majority of patients were male (74%), and Caucasian (58%). Of the 591 patients, 345 (58%) had additional inpatient or emergency healthcare utilization accounting for 769 additional visits (median of 3 visits per person). Of the 769 encounters, 534 (69%) were inpatient and 235 (31%) were emergency visits not resulting in an admission. The most prevalent ICD-9 codes listed were pressure ulcer, neurogenic bowel, neurogenic bladder, urinary tract infection, fluid electrolyte imbalance, hypertension, and tobacco use.

Conclusion: Individuals with SCI experience high levels of healthcare utilization which are costly and may be preventable. Increasing our understanding of the prevalence and causes for healthcare utilization after acute SCI is important to target preventive strategies.  相似文献   

69.
Objective/Background: To assess frequency domain heart rate variability (HRV) parameters at rest and in response to postural autonomic provocations in individuals with spinal cord injury (SCI) and investigate the autonomic influences on the heart of different physical activities.

Design: Cross-sectional study.

Methods: Ten subjects with complete cervical SCI and fourteen subjects with complete low thoracic SCI were prospectively recruited from the community and further divided in sedentary and physically active groups, the latter defined as regular weekly 4 hour physical activity for the preceding 3 months. Sixteen healthy individuals matched for sex and age were recruited to participate in the control group. The Low Frequency (LF), High Frequency (HF) powers and the LF/HF ratio of HRV were measured from continuous electrocardiogram (ECG) recordings at rest and after sitting using a fast Fourier transformation.

Outcome measures: The LF,HF, and the LF/HF ratio at rest and after sitting.

Results: A significant decrease in all HRV parameters in patients with SCI was found compared to controls. The change in HF, LF and LF/HF following sitting maneuver was significantly greater in controls as compared with the SCI group and greater in subjects with paraplegia as compared to subjects with tetraplegia. Better HRV values and enhanced vagal activity appears to be related to the type of physical activity in active subjects with paraplegia.

Conclusion: In this cohort of subjects spectral parameters of HRV were associated with the level of the injury. Passive standing was associated with higher HRV values in subjects with paraplegia.  相似文献   

70.
BackgroundDental trauma injuries are frequent in children and adolescents and can result in a sequela of future complications. Lateral luxation injuries are diagnosed when a tooth becomes displaced in a position other than axial and is often associated with alveolar bone fracture. Although the tooth is not immediately lost, pulp canal obliteration or pulpal necrosis can occur. The objective of this systematic review was to gather existing data on lateral luxation injuries to mature teeth to evaluate their overall prognosis and reported complications.Types of Studies ReviewedThe authors conducted a systematic search of the literature using MEDLINE, PubMed, Embase, and Cochrane databases in February 2019. They hand searched reference lists to identify additional literature. The authors included prospective and retrospective observational studies in the search. They screened a total of 291 articles, downloaded 28 articles, and included 4 articles in the study.ResultsThe most frequent complication reported for mature teeth with lateral luxation was pulpal necrosis (44.2%). Less frequent findings included surface resorption (14.0%), inflammatory resorption (8.5%), pulp canal obliteration (8.1%), and replacement resorption (0.9%). The included studies were cohort studies, which resulted in great heterogeneity, and the authors could not attempt a meta-analysis.Conclusions and Practical ImplicationsA large number of permanent teeth that experience lateral luxation are at risk of developing pulpal necrosis and other complications. Careful follow-up is required for these patients to treat complications as early as possible. Furthermore, the authors of this systematic review emphasize the importance of consistent reporting of dental trauma outcomes.  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