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   1372篇
  免费   106篇
  国内免费   6篇
耳鼻咽喉   7篇
儿科学   16篇
妇产科学   43篇
基础医学   155篇
口腔科学   60篇
临床医学   193篇
内科学   266篇
皮肤病学   60篇
神经病学   87篇
特种医学   52篇
外科学   219篇
综合类   4篇
一般理论   1篇
预防医学   62篇
眼科学   3篇
药学   117篇
中国医学   1篇
肿瘤学   138篇
  2023年   5篇
  2022年   13篇
  2021年   34篇
  2020年   26篇
  2019年   27篇
  2018年   25篇
  2017年   34篇
  2016年   35篇
  2015年   45篇
  2014年   55篇
  2013年   39篇
  2012年   88篇
  2011年   109篇
  2010年   60篇
  2009年   47篇
  2008年   77篇
  2007年   87篇
  2006年   62篇
  2005年   64篇
  2004年   65篇
  2003年   61篇
  2002年   55篇
  2001年   34篇
  2000年   30篇
  1999年   25篇
  1998年   12篇
  1997年   13篇
  1996年   11篇
  1995年   9篇
  1994年   5篇
  1993年   8篇
  1992年   14篇
  1991年   11篇
  1990年   18篇
  1989年   13篇
  1988年   18篇
  1987年   21篇
  1986年   13篇
  1985年   18篇
  1984年   10篇
  1983年   14篇
  1982年   12篇
  1981年   5篇
  1980年   5篇
  1979年   9篇
  1977年   4篇
  1975年   8篇
  1974年   3篇
  1972年   5篇
  1966年   4篇
排序方式: 共有1484条查询结果,搜索用时 583 毫秒
21.
Purpose: Long‐term results in the clinical outcome of different implant systems, including high patient numbers and a long follow‐up time, are rare. This retrospective study evaluated the cumulative survival rate of a self‐tapping, cylindrical implant system with a conical implant‐abutment connection after 10 years of prosthetic loading. Materials and Methods: A total of 516 TiOblast? implants (Astra Tech AB, Mölndal, Sweden) were placed in 108 patients. The patients were treated in the Department of Oral and Maxillofacial Surgery, Johannes Gutenberg University, Mainz, Germany, between September 1994 and May 2005. The main indications for implantation were the treatment of edentulous mandibles (74%) and partial edentulism (15%). Twenty‐three implants were placed postradiation, and a further 64 implants were irradiated after insertion. In 153 implants, a bony augmentation was conducted prior to implantation. Results: The in situ rate was 89.7% after an average implantation time of 108 months. Eighty‐three patients with 403 implants were available for investigation. Seventeen patients with 76 implants have died since 1994. Absence of osseointegration (n = 22), peri‐implantitis (n = 18), fracture of the implants (n = 9), failing of primary stability (n = 2), and implants next to tumors (n = 2) were the reasons of explantation in 26 patients. Under analysis with different implant success‐assessment criteria, the success rate showed results from 76 to 89%. Conclusion: With respect to the critical patient selection including a high number of patients with minor and major augmentations, the 10‐year clinical use of the studied implant system showed acceptable results.  相似文献   
22.
23.
24.
A lack of appropriate diagnostic tools for prostate cancer has led to overdiagnosis and over treatment. In a recent publication in the New England Journal of Medicine, Hamdy et al showed no difference in the outcomes of patients that had undergone either radical prostatectomy, radiotherapy, or active monitoring. In an effort to enhance clinical stratification, the development of improved, more accurate diagnostic tools is actively being pursued. Herein, we explore recent advances in prostate cancer screening, including biomarker assays, genetic testing, and specialized fields, such as mathematical oncology. These newly developed, highly sensitive diagnostic assays may potentially aid clinicians in selecting appropriate therapies for patients in the very near future.  相似文献   
25.
26.

Introduction

Magnetic resonance imaging using the delayed contrast-enhanced (DE-MRI) method can be used for characterizing and quantifying myocardial infarction (MI). Electrocardiogram (ECG) score after the acute phase of MI can be used to estimate the portion of left ventricular myocardium that has infracted. There are no comparison of serial changes on ECG and DE-MRI measuring infarct size.

Aim

The general aim of this study was to describe the acute, healing, and chronic phases of the changes in infarct size estimated by the ECG and DE-MRI. The specific aim was to compare estimates of the Selvester QRS scoring system and DE-MRI to identify the difference between the extent of left ventricle occupied by infarction in the acute and chronic phases.

Methods

In 31 patients (26 men, age 56 ± 9) with reperfused ST-elevation MI (11 anterior, 20 inferior), standard 12-lead ECG and DE-MRI were taken from 1 to 2 days (acute), 1 month (healing), and 6 months (chronic) after the MI. Selvester QRS scoring was used to estimate the infarct size from the ECG.

Results

The correlation values between infarct size measured by DE-MRI and QRS scoring range from 0.33 to 0.43 higher for anterior than inferior infarcts. The infarct size estimated by QRS scoring was larger (about 5% of the left ventricle) than infarct size by DE-MRI acute and 1 month, but at 6 months, there was no difference. In about half of the patients, the QRS score agreed with DE-MRI in change of infarct size from acute to 6 months.

Conclusion

In conclusion, the Selvester QRS scoring system is in half of the patients with reperfused first time MI in good accordance with DE-MRI in identifying a decrease or no change in the extent of left ventricle occupied by infarction in the acute and chronic phases.  相似文献   
27.
The new psychoactive substance (NPS) 3‐HO‐PCP, a phencyclidine (PCP) analog, was detected in a law enforcement seizure and in forensic samples in Denmark. Compared with PCP, 3‐HO‐PCP is known to be a more potent dissociative NPS, but no toxicokinetic investigations of 3‐HO‐PCP are yet available. Therefore, 3‐HO‐PCP was quantified in in vivo samples, and the following were investigated: plasma protein binding, in vitro and in vivo metabolites, and metabolic targets. All samples were separated by liquid chromatography and analyzed by mass spectrometry. The unbound fraction in plasma was determined as 0.72 ± 0.09. After in vitro incubation with pooled human hepatocytes, four metabolites were identified: a piperidine‐hydroxyl‐and piperidine ring opened N‐dealkyl‐COOH metabolite, and O‐glucuronidated‐ and O‐sulfate‐conjugated metabolites. In vivo, depending on the sample and sample preparation, fewer metabolites were detected, as the O‐sulfate‐conjugated metabolite was not detected. The N‐dealkylated‐COOH metabolite was the main metabolite in the deconjugated urine sample. in vivo analytical targets in blood and brain samples were 3‐HO‐PCP and the O‐glucuronidated metabolite, with 3‐HO‐PCP having the highest relative signal intensity. The drug levels of 3‐HO‐PCP quantified in blood were 0.013 and 0.095 mg/kg in a living and a deceased subject, respectively. The 3‐HO‐PCP concentrations in deconjugated urine in a sample from a living subject and in post‐mortem brain were 7.8 and 0.16 mg/kg, respectively. The post mortem results showed a 1.5‐fold higher concentration of 3‐HO‐PCP in the brain tissue than in the post mortem blood sample.  相似文献   
28.
29.
Clinical Oral Investigations - This study evaluated the reproducibility of electronic color determination system evaluations of the marginal gingiva, which could be important for adhesive cervical...  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