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   3586篇
  免费   284篇
  国内免费   7篇
耳鼻咽喉   59篇
儿科学   135篇
妇产科学   79篇
基础医学   497篇
口腔科学   49篇
临床医学   407篇
内科学   626篇
皮肤病学   41篇
神经病学   448篇
特种医学   94篇
外科学   439篇
综合类   40篇
一般理论   4篇
预防医学   416篇
眼科学   39篇
药学   308篇
  1篇
中国医学   4篇
肿瘤学   191篇
  2023年   33篇
  2022年   62篇
  2021年   109篇
  2020年   83篇
  2019年   92篇
  2018年   100篇
  2017年   71篇
  2016年   75篇
  2015年   102篇
  2014年   127篇
  2013年   181篇
  2012年   277篇
  2011年   270篇
  2010年   118篇
  2009年   118篇
  2008年   165篇
  2007年   190篇
  2006年   160篇
  2005年   131篇
  2004年   110篇
  2003年   112篇
  2002年   110篇
  2001年   69篇
  2000年   87篇
  1999年   79篇
  1998年   34篇
  1997年   23篇
  1996年   29篇
  1995年   23篇
  1994年   22篇
  1992年   57篇
  1991年   46篇
  1990年   46篇
  1989年   40篇
  1988年   26篇
  1987年   50篇
  1986年   35篇
  1985年   16篇
  1984年   20篇
  1983年   25篇
  1982年   23篇
  1981年   19篇
  1980年   18篇
  1979年   32篇
  1978年   31篇
  1976年   22篇
  1975年   18篇
  1973年   19篇
  1972年   16篇
  1971年   20篇
排序方式: 共有3877条查询结果,搜索用时 31 毫秒
1.
2.
BACKGROUND: During the last 15 years, a substantial number of population-based, clinical, laboratory, and animal studies have been published that reported findings on the relationship between periodontal disease and cardiovascular disease. The Periodontitis and Vascular Events (PAVE) pilot study was conducted to investigate the feasibility of a randomized secondary prevention trial to test whether treatment of periodontal disease reduces the risk for cardiovascular disease. This article describes the occurrence of adverse events during the pilot study. METHODS: The PAVE pilot study was a multicenter, randomized trial comparing periodontal therapy to community dental care. Baseline and follow-up clinic visits included a periodontal examination; blood, subgingival plaque, and crevicular fluid specimen collection; and medical and dental histories. Telephone follow-up contacts were scheduled to occur 3 months after randomization and every 6 months thereafter to assess adverse events or endpoints. RESULTS: Cardiovascular adverse events occurred with similar frequency (23 versus 24 [P = 0.85] in the community control and the treatment groups, respectively). There were 15 serious adverse events (SAEs) with a non-significantly higher percentage occurring in the community care group (6.6% versus 3.3%; P = 0.19). A time-to-event analysis of patterns of SAEs indicated that subjects in the periodontal therapy group tended to be less likely to experience an SAE over the entire 25 months of the study. CONCLUSION: For those individuals who remained in the study, it appears that provision of periodontal scaling and root planing treatment to individuals with heart disease resulted in a similar pattern of adverse events as seen in the community care group, which also received some treatment.  相似文献   
3.
Longitudinal study of bone density and periodontal disease in men   总被引:2,自引:0,他引:2  
Bone loss is a feature of both periodontitis and osteoporosis, and periodontal destruction may be influenced by systemic bone loss. This study evaluated the association between periodontal disease and bone mineral density (BMD) in a cohort of 1347 (137 edentulous) older men followed for an average of 2.7 years. Participants were recruited from the Osteoporotic Fractures in Men Study. Random half-mouth dental measures included clinical attachment loss (CAL), pocket depth (PD), calculus, plaque, and bleeding. BMD was measured at the hip, spine, and whole-body, by dual-energy x-ray absorptiometry, and at the heel by ultrasound. After adjustment for age, smoking, race, education, body mass index, and calculus, there was no association between number of teeth, periodontitis, periodontal disease progression, and either BMD or annualized rate of BMD change. We found little evidence of an association between periodontitis and skeletal BMD among older men.  相似文献   
4.
5.
6.
Macroalbuminuria, defined as urine albumin excretion rate (AER)≥300 mg/d, has long been considered a stage of irreversible kidney damage that leads reliably to GFR loss. We examined the long-term renal outcomes of persons with type 1 diabetes who developed incident macroalbuminuria during the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study. One hundred fifty-nine participants developed incident macroalbuminuria and were subsequently followed for a median duration of 9 years (maximum of 25 years). At the time of macroalbuminuria diagnosis, mean (SD) age was 37 (9) years, mean (SD) duration of diabetes was 17 (5) years, median AER was 524 mg/d, and mean (SD) eGFR was 108 (20) ml/min per 1.73 m2. Ten years after macroalbuminuria diagnosis, the cumulative incidence of a sustained reduction in AER to <300 mg/d was 52%, mostly but not entirely under treatment with renin-angiotensin system inhibitors. The cumulative incidence of impaired GFR (sustained eGFR<60 ml/min per 1.73 m2) 10 years after macroalbuminuria diagnosis was 32%, including 16% who developed ESRD. Lower hemoglobin A1c and BP and regression to AER<300 mg/d were associated with reduced risk of developing impaired GFR. In conclusion, people with type 1 diabetes who develop macroalbuminuria are at high risk of progressive kidney disease. However, through at least 10 years of follow-up, AER could often be controlled, and GFR frequently remained in the normal range.Macroalbuminuria, defined as urine albumin excretion rate (AER)≥300 mg/d, has long been considered a stage of irreversible kidney damage that leads reliably to GFR loss.1 In early published type 1 diabetes cohorts, macroalbuminuria was associated with a 15-year cumulative incidence of ESRD as high as 75%.2,3 However, contemporary long-term renal outcomes of macroalbuminuria have not been fully characterized.The Diabetes Control and Complications Trial (DCCT) and its observational follow-up, the Epidemiology of Diabetes Interventions and Complications (EDIC) study, present a valuable opportunity to examine macroalbuminuria and its long-term clinical outcomes. In DCCT/EDIC, the onset of macroalbuminuria can be defined with confidence using frequent longitudinal measurements of AER, participants have been followed for up to 25 years after the diagnosis of macroalbuminuria, and outcomes were meticulously recorded using standardized methods. Previous work in this cohort has shown that most cases of impaired GFR are preceded by macroalbuminuria,4 which is associated with a 50-fold higher risk of developing impaired GFR (eGFR<60 ml/min per 1.73 m2).5 Here, we extend these studies by comprehensively evaluating the long-term renal outcomes of incident macroalbuminuria in the DCCT/EDIC cohort and examining the risk factors for its progression to impaired GFR.  相似文献   
7.
Hormonal changes in brain dead patients   总被引:1,自引:0,他引:1  
Thirty neurologically impaired (Glasgow Coma Score less than 7) patients were evaluated to determine if changes in serum levels of thyroid hormone, cortisol, insulin, or lactate suggest that replacement therapy is needed before removal of organs for donation. Serum levels of free thyroxine (fT4), thyroid-stimulating hormone (TSH), reverse T3 (rT3), cortisol, insulin, and lactate were monitored in 16 patients before and after brain death and in 14 additional patients who were similarly compromised but did not become brain dead. Low fT3, normal fT4, and normal or high rT3 as found in most patients were consistent with a variant of the euthyroid sick syndrome although TSH was elevated in some patients. Cortisol, insulin, and lactate levels were also normal or high. No correlation was found between low thyroid hormones and elevated lactate or the amount of vasopressor needed to sustain BP. No significant changes occurred in hormone or lactate levels after brain death. The explanation for an elevated lactate remains unclear but we do not believe this single finding justifies the diagnosis of a hypothyroid state in these patients or the administration of thyroid hormone to brain dead organ donors.  相似文献   
8.
9.
10.

Objective

The objective of this study was to review current literature on the comparison of the radiological outcome of cervical arthroplasty with fusion after anterior discectomy for radiculopathy.

Materials and Methods

A literature search was performed in PubMed, Embase, Web of Science, Cochrane, CENTRAL, and CINAHL using a sensitive search string combination. Studies were selected by predefined selection criteria (patients exclusively suffering from cervical radiculopathy), and risk of bias was assessed using a validated Cochrane checklist adjusted for this purpose. Additionally, an overview of results of articles published in 21 meta-analyses was added, considering a group of patients with myelopathy with or without radiculopathy.

Results

Seven articles that compared intervertebral devices in patients with radiculopathy (excluding patients with myelopathy) were included in the study. Another 31 articles were studied as a mixed group, including patients with myelopathy and radiculopathy. Apart from three studies with low risk of bias, all other articles showed intermediate or high risk of bias. Heterotopic ossification was reported to be present in circa 10% of patients, seemingly predominant in patients with radiculopathy, with a very low level of evidence. Radiological signs of adjacent segment disease were present at baseline in 50% of patients, and there is a low level of evidence that this increased more (10%–20%) in the fusion group at long-term follow-up. However, this was only studied in the mixed study population, which is degenerative by diagnosis.

Conclusion

Although the cervical disc prosthesis was introduced to decrease adjacent level disease, convincing radiological evidence for this benefit is lacking. Heterotopic ossification as a complicating factor in the preservation of motion of the device is insufficiently studied. Regarding purely radiological outcomes, currently, no firm conclusion can be drawn for implanting cervical prosthesis versus performing fusion.  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