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   12915篇
  免费   597篇
  国内免费   79篇
耳鼻咽喉   177篇
儿科学   252篇
妇产科学   246篇
基础医学   1557篇
口腔科学   725篇
临床医学   1020篇
内科学   3133篇
皮肤病学   230篇
神经病学   1078篇
特种医学   282篇
外科学   2082篇
综合类   68篇
一般理论   6篇
预防医学   872篇
眼科学   258篇
药学   747篇
中国医学   48篇
肿瘤学   810篇
  2024年   14篇
  2023年   124篇
  2022年   257篇
  2021年   485篇
  2020年   280篇
  2019年   376篇
  2018年   445篇
  2017年   324篇
  2016年   322篇
  2015年   383篇
  2014年   560篇
  2013年   689篇
  2012年   1131篇
  2011年   1117篇
  2010年   622篇
  2009年   557篇
  2008年   906篇
  2007年   872篇
  2006年   786篇
  2005年   747篇
  2004年   640篇
  2003年   538篇
  2002年   522篇
  2001年   69篇
  2000年   60篇
  1999年   72篇
  1998年   106篇
  1997年   67篇
  1996年   62篇
  1995年   54篇
  1994年   47篇
  1993年   41篇
  1992年   29篇
  1991年   25篇
  1990年   15篇
  1989年   13篇
  1988年   12篇
  1987年   19篇
  1986年   25篇
  1985年   17篇
  1984年   15篇
  1983年   9篇
  1982年   9篇
  1981年   17篇
  1980年   18篇
  1979年   12篇
  1977年   10篇
  1975年   11篇
  1974年   10篇
  1969年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
BackgroundRevision total knee arthroplasty (rTKA) rates are increasing in younger patients. Few studies have assessed outcomes of initial aseptic rTKA performed for younger patients compared with traditional-aged patients.MethodsA detailed medical record review was performed to identify patient demographics, medical comorbidities, surgical rTKA indications, timing from index TKA to rTKA, subsequent reoperation rates, component rerevision rates, and salvage procedures for 147 young patients (158 knees) aged 55 years and younger and for a traditional older cohort of 276 patients (300 knees) between 60 and 75 years. Univariate analysis was performed to assess differences in these primary variables, and a log-rank test was used to estimate 5-year implant survival based on either reoperation or component revision and salvage procedures.ResultsYounger TKA patients were more likely to undergo initial aseptic rTKA within 2 years of their primary TKA (52.5% vs 29.0%, P < .001) and were more likely to undergo early reoperation (17.7% vs 9.7%, P = .02) or component rerevision (11.4% vs 6.0%, P < .05) after rTKA. Infection and extensor mechanism complications were more commonly noted in younger patients. Estimated 5-year survival was also lower for both reoperation (59.4% vs 65.7%, P = .02) and component rerevision or salvage (65.8% vs 80.1%, P = .02).ConclusionEarly reoperation and component re-rTKA were performed nearly twice as often in younger rTKA than traditional-aged TKA patients. Care should be given to reduce perioperative infection and extensor mechanism failures after rTKA in younger patients.  相似文献   
112.
BackgroundPatient-reported outcomes (PRO) obtained from follow-up survey data are essential to understanding the longitudinal effects of bariatric surgery. However, capturing data among patients who are well beyond the recovery period of surgery remains a challenge, and little is known about what factors may influence follow-up rates for PRO.ObjectivesTo assess the effect of hospital practices and surgical outcomes on patient survey completion rates at 1 year after bariatric surgery.SettingProspective, statewide, bariatric-specific clinical registry.MethodsPatients at hospitals participating in the Michigan Bariatric Surgery Collaborative are surveyed annually to obtain information on weight loss, medication use, satisfaction, body image, and quality of life following bariatric surgery. Hospital program coordinators were surveyed in June 2017 about their practices for ensuring survey completion among their patients. Hospitals were ranked based on 1-year patient survey completion rates between 2011 and 2015. Multivariable regression analyses were used to identify associations between hospital practices, as well as 30-day outcomes, on hospital survey completion rankings.ResultsOverall, patient survey completion rates at 1 year improved from 2011 (33.9% ± 14.5%) to 2015 (51.0% ± 13.0%), although there was wide variability between hospitals (21.1% versus 77.3% in 2015). Hospitals in the bottom quartile for survey completion rates had higher adjusted rates of 30-day severe complications (2.6% versus 1.7%, respectively; P = .0481), readmissions (5.0% versus 3.9%, respectively; P = .0157), and reoperations (1.5% versus .7%, respectively; P = .0216) than those in the top quartile. While most hospital practices did not significantly impact survey completion at 1 year, physically handing out surveys during clinic visits was independently associated with higher completion rates (odds ratio, 13.60; 95% confidence interval, 1.99?93.03; P =.0078).ConclusionsHospitals vary considerably in completion rates of patient surveys at 1 year after bariatric surgery, and lower rates were associated with hospitals that had higher complication rates. Hospitals with the highest completion rates were more likely to physically hand surveys to patients during clinic visits. Given the value of PRO on longitudinal outcomes of bariatric surgery, improving data collection across multiple hospital systems is imperative.  相似文献   
113.
IntroductionThe purpose of the present study is to analyse the prevalence and distribution of asbestos lung residue in the Barcelona urban population.Material and methodsLung autopsy samples were obtained from 35 individuals who had lived in Barcelona. The close family was interviewed in order to rule out asbestos exposure. Samples were obtained from three areas of the right lung during the autopsy: upper lobe apex, lower lobe apex, and lower lobe base. The samples were treated to remove organic material. The inorganic residue was analysed using a light microscope. The results were expressed as asbestos bodies (AB) per gram of dry tissue. Levels greater than 1000AB/g of dry tissue were considered as potentially causing disease.ResultsAB were detected in 29(83%) of the subjects, of which 86% had levels less than 300AB/g. Only one individual (3%) had values greater than 1000AB/g dry tissue. The asbestos residue was higher in the lower lung lobe in 17 individuals (48%) than in the rest, although no significant differences were seen as regards AB residue in the three lung areas studied.ConclusionsThe results of this study show that the urban population of Barcelona has asbestos levels in the lung that vary between 0 and 300AB/g dry tissue. No differences in the asbestos residues were detected in the lung areas studied in this population.  相似文献   
114.
Study Type – Diagnostic (case series)
Level of Evidence 4

OBJECTIVES

To assess the prostate cancer detection rate and predictive factors for prostate cancer after transrectal ultrasonography (TRUS)‐guided transperineal saturation re‐biopsies of the prostate, using a 24‐core scheme.

PATIENTS AND METHODS

We evaluated 143 consecutive patients undergoing TRUS‐guided transperineal saturation re‐biopsy of the prostate using a 24‐core scheme. The inclusion criteria were a previous negative biopsy and a prostate‐specific antigen (PSA) level of ≥10.0 ng/mL, or of 4.0–10.0 ng/mL with a free/total ratio of <20% or an abnormal digital rectal examination or previous high‐grade prostatic intraepithelial neoplasia (HGPIN) or atypical small acinar proliferation (ASAP).

RESULTS

The mean (sd ) age of the patients was 66.5 (6.1) years and the median (interquartile range) PSA level was 9.0 (6.1–12.8) ng/mL. The number of previous biopsies was one in 59% of patients, two in 26% and three or more in 15%. We detected prostate cancer in 26%, ASAP in 5.6% and HGPIN in 2.1%. The cancer detection rate was 47%, 25.5% and 14% for prostate volumes of <40, 40–60 and ≥60 mL, respectively (P = 0.002). On a multivariate analysis the total prostate volume (40–60 vs <40 mL, hazard ratio 5.683; >60 vs <40 mL, hazard ratio 6.965; P = 0.01) was the only significant predictor of prostate cancer at saturation biopsy.

CONCLUSIONS

TRUS‐guided transperineal saturation re‐biopsy of the prostate using a 24‐core scheme resulted in a high cancer detection rate also in patients who had had two or more previous biopsies. The total prostate volume was the only predictor of prostate cancer.  相似文献   
115.
116.
117.
Objective. Our aim has been evaluating the influence of an acute dose of cinacalcet on the gastrointestinal hormonal responses to a test meal in uraemic patients with secondary hyperparathyroidism undergoing peritoneal dialysis (PD) or haemodialysis (HD). METHODS: Twenty patients (11 PD, 9 HD) on cinacalcet treatment (30-120 mg/day) were studied. Twelve patients (1 PD, 11 HD) who never received cinacalcet were studied as control group. Each patient received a test meal with blood samples at 0, 2 and 4 h. At 0 time, patients in the cinacalcet group received their usual oral dose of this calcimimetic. Plasma concentrations of intact parathyroid hormone (PTH), vasoactive intestinal peptide (VIP), ghrelin, substance P, serotonin, cholecystokinin (CCK) and gastrin were quantified at 0, 2 and 4 h. RESULTS: No significant differences in baseline concentrations of serum VIP, ghrelin, substance P, serotonine, CCK and gastrin were found between controls and cinacalcet-treated patients. In comparison with the control group, cinacalcet administration was followed by a significant decrease in VIP concentration at 4 h and a significant increase in substance P at 4 h. However, the areas under the curves of all studied gut hormones were similar in both groups. CONCLUSION: An acute dose of cinacalcet exerts minimal influence on gut hormone responses to a mixed meal in dialysis patients on chronic therapy with this drug. The small but significant differences between control subjects and patients on cinacalcet in VIP and substance P levels at 4 h should be investigated in symptomatic patients.  相似文献   
118.
Patients with chronic kidney disease frequently experience loss of appetite (anorexia), which increases in severity during the progression of the disease and may lead to protein-energy wasting, morbidity, and mortality. Anorexia represents a multiple, complex, and multifactorial disorder that may have its origin in renal failure (contemplating not only retention of uremic toxins but also peptides and cytokines) but that later on also involves metabolic abnormalities not yet corrected by dialysis therapy. This paper reviews current knowledge about the clinical signs of uremic anorexia as well as mechanisms involved. Based on megestrol acetate interventions and the recent observation that sex may modulate uremic appetite behavior, the potential role of sex hormones in treating chronic kidney disease anorexia needs to be further explored.  相似文献   
119.

Background:

The characteristics of the ideal type of mesh are still being debated. Mesh shrinkage and fixation have been associated with complications. Avoiding shrinkage and fixation would improve hernia recurrence rates and complications. To our knowledge, this is the first study of a device with a self-expanding frame for laparoscopic hernia repair.

Methods:

Six Rebound Hernia Repair Devices were placed laparoscopically in pigs. This device is a condensed polypropylene, super-thin, lightweight, macro-porous mesh with a self-expanding Nitinol frame. The devices were assessed for adhesions, shrinkage, and histological examination. Laboratory and radiologic evaluations were also performed.

Results:

The handling properties of the devices facilitated their laparoscopic placement. They were easily identified with simple x-rays. The mesh was firmly integrated within the surrounding tissue. One device was associated with 3 small adhesions. The other 5 HRDs had no adhesions. We noted no shrinkage or folding. All devices preserved their original size and shape.

Conclusions:

At this evaluation stage, we found that the Rebound Hernia Repair Device may serve for laparoscopic hernia repair and has favorable handling properties. It prevents folding and shrinkage of the mesh. It may eliminate the need for fixation, thus preventing chronic pain. The Nitinol frame also allowed radiologic evaluation for gross movement. Further studies will be needed to evaluate its clinical application.  相似文献   
120.
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