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   1167篇
  免费   75篇
  国内免费   3篇
耳鼻咽喉   30篇
儿科学   22篇
妇产科学   37篇
基础医学   187篇
口腔科学   3篇
临床医学   83篇
内科学   246篇
皮肤病学   95篇
神经病学   99篇
特种医学   31篇
外科学   170篇
综合类   6篇
预防医学   137篇
眼科学   7篇
药学   45篇
中国医学   3篇
肿瘤学   44篇
  2023年   6篇
  2022年   13篇
  2021年   31篇
  2020年   17篇
  2019年   26篇
  2018年   46篇
  2017年   10篇
  2016年   22篇
  2015年   19篇
  2014年   35篇
  2013年   38篇
  2012年   52篇
  2011年   74篇
  2010年   41篇
  2009年   33篇
  2008年   46篇
  2007年   80篇
  2006年   74篇
  2005年   52篇
  2004年   50篇
  2003年   60篇
  2002年   49篇
  2001年   37篇
  2000年   43篇
  1999年   25篇
  1998年   9篇
  1996年   4篇
  1995年   9篇
  1994年   4篇
  1993年   2篇
  1992年   18篇
  1991年   16篇
  1990年   19篇
  1989年   17篇
  1988年   23篇
  1987年   24篇
  1986年   22篇
  1985年   18篇
  1984年   14篇
  1983年   10篇
  1981年   3篇
  1979年   4篇
  1978年   4篇
  1975年   3篇
  1974年   5篇
  1973年   3篇
  1972年   12篇
  1971年   9篇
  1970年   5篇
  1944年   1篇
排序方式: 共有1245条查询结果,搜索用时 15 毫秒
21.
22.
This paper presents a theoretical model derived from a grounded theory analysis of interviews with 19 men who had had a vasectomy three years previously. The aim was to track men's experience of vasectomy through decision making, surgery and adjustment and to develop a model to shed light on the process. Early studies of vasectomy had suggested that men adopt more stereotypically masculine behaviours after vasectomy and their authors had conjectured that these were compensatory for a diminished sense of masculinity. Interesting findings from the present study suggest that, for these participants at least, vasectomy often enhanced their sense of masculinity. Surgery was sometimes construed as a “bloodbath” heroically endured and part of the construction of a valued identity of a “family man”. Peer pressure, particularly in the workplace, appeared to be a powerful motivator when making the decision to be sterilized and the authors suggest that vasectomy can be a passport to membership of a socially valued group.  相似文献   
23.
24.

Introduction

Airtraq laryngoscope is a new and single use device for endotracheal intubation. Few studies showed the superiority of the Airtraq comparing to Macintosh laryngoscope in the setting of difficult intubation.

Study design

To compare the performance of these two laryngoscopes by simulating a situation of reduced mobility of the cervical spine by applying the Manual in-line stablization (MILS) maneuver.

Patients and methods

After obtaining the approval of the ethic committee, we realized a prospective single blind randomized study. During a 6-month period, 120 consenting patients scheduled for ORL or ophthalmologic surgery were included. They all had general anesthesia and orotracheal intubation. These patients were randomly and equally divided in two groups (n = 60), depending on the type of the laryngoscope used (Airtraq or Macintosh). Were excluded from the study the patients with history or criteria predicting difficult intubation. Each patient was intubated by one of the five experimented anesthetists selected for this work. The principle judgment criteria were: i) the time taken for the orotracheal intubation and ii) the intubation difficulty score (IDS). The secondary judgment criterion was the hemodynamic modifications after the endotracheal intubation.

Results

Demographic and upper airway track variables were comparable between the two groups. There was no case of failure of intubation in this serie. Nonetheless, all the patients of the Airtaq group were intubated from the first attempt, whereas half of the patients of the Macintosh group were intubated after the third attempt. Comparing to the Macintosh, the Airtraq reduces the time taken for the orotracheal intubation (14 ± 1 s vs 19 ± 3 s, P = 0.01), the necessity of additional maneuver to facilitate the intubation, and the intubation difficulty score (0.7 ± 0.3 vs 3.8 ± 1, P < 0.001). Orotracheal intubation using the Airtraq laryngoscope caused less hemodynamic stimulation than using the Macintosh.

Conclusion

Our study showed the usefulness of the Airtraq laryngoscope for endotracheal intubation for patients presenting conditions of difficult intubation such as reduced mobility of the cervical spine.  相似文献   
25.
26.

Purpose

Premature physeal closure of the proximal femoral physis has been reported in Legg-Calve-Perthes Disease (LCPD). However, the timing of its occurrence had not yet been reported. We proposed (1) to determine the timing of premature physeal closure in unilateral LCPD with serial radiographic evaluation, and (2) to evaluate the relationship between the premature physeal closure and Herring classification, leg-length discrepancy (LLD), Stulberg classification, and trochanteric overgrowth.

Methods

We performed a retrospective study with serial radiographs of 27 patients diagnosed with LCPD. The difference in the timing of physeal closure between the hips was calculated. The involved hip was classified according to Herring classification. The LLD and ATD index at latest follow up was measured. The mean values were calculated and statistical comparison of variables was done using the Fisher’s exact test.

Results

The mean difference of physeal closure at the involved hip compared to the uninvolved side was 3.5 years (range, two to five years). Hips demonstrating premature physeal closure were associated with Herring B/C and C (p?=?0.01) and LLD >1 cm (p?=?0.02). There is no correlation between Stulberg classification, trochanteric overgrowth and premature physeal closure (p?=?0.06 and p?=?0.19).

Conclusions

We may expect premature physeal closure of the proximal femoral physis in patients with LCPD to occur 3.5 years earlier than normal hips. Presence of premature physeal closure can be an adjunct diagnostic tool in the prognostication of LCPD outcomes. Future studies directed toward premature physeal closure in LCPD and associated growth disturbances are necessary.  相似文献   
27.
Calcitriol deficiency and phosphate retention are two main factors in the pathogenesis of renal hyperparathyroidism. In spite of normal serum levels, phosphate may have an important role even in moderate RI. The aim of this study was to evaluate the effect of dietary phosphorus restriction on serum levels of calcitriol in patients with moderate RI. We studied 21 patients (7 F/14 M); mean age 61.7 +/- 15 years old; corrected creatinine clearance 51.4 +/- 14 ml/m. Serum PTH, calcitriol 25(OH)D3, calcium, phosphorus and urinary excretion of calcium and phosphorus were measured before and after 30 days on phosphorus restricted diet (700 mg/day). RESULTS: [table: see text] CONCLUSIONS: Our patients with moderate RI have elevated serum levels of PTH while calcitriol was in the lower normal range. Dietary phosphorus restriction resulted in a significant decrease in PTH levels and a significant increase in serum calcitriol concentrations. The levels of 25(OH)D3 did not change in this study.  相似文献   
28.
29.
Nanoporous polymers are becoming increasingly interesting materials for electrochemical applications, as their large surface areas with redox-active sites allow efficient adsorption and diffusion of ions. However, their limited electrical conductivity remains a major obstacle in practical applications. The conventional approach that alleviates this problem is the hybridisation of the polymer with carbon-based additives, but this directly prevents the utilisation of the maximum capacity of the polymers. Here, we report a layer-by-layer fabrication technique where we separated the active (porous polymer, top) layer and the conductive (carbon, bottom) layer and used these “layered” electrodes in a supercapacitor (SC). Through this approach, direct contact with the electrolyte and polymer material is greatly enhanced. With extensive electrochemical characterisation techniques, we show that the layered electrodes allowed a significant contribution of fast faradic surface reactions to the overall capacitance. The electrochemical performance of the layered-electrode SC outperformed other reported porous polymer-based devices with a specific gravimetric capacitance of 388 F·g−1 and an outstanding energy density of 65 Wh·kg−1 at a current density of 0.4 A·g−1. The device also showed outstanding cyclability with 90% of capacitance retention after 5000 cycles at 1.6 A·g−1, comparable to the reported porous polymer-based SCs. Thus, the introduction of a layered electrode structure would pave the way for more effective utilisation of porous organic polymers in future energy storage/harvesting and sensing devices by exploiting their nanoporous architecture and limiting the negative effects of the carbon/binder matrix.  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