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   4512篇
  免费   224篇
  国内免费   49篇
耳鼻咽喉   68篇
儿科学   71篇
妇产科学   93篇
基础医学   618篇
口腔科学   110篇
临床医学   414篇
内科学   763篇
皮肤病学   150篇
神经病学   322篇
特种医学   203篇
外科学   577篇
综合类   32篇
一般理论   3篇
预防医学   243篇
眼科学   67篇
药学   576篇
中国医学   110篇
肿瘤学   365篇
  2023年   31篇
  2022年   113篇
  2021年   183篇
  2020年   90篇
  2019年   116篇
  2018年   143篇
  2017年   105篇
  2016年   140篇
  2015年   195篇
  2014年   255篇
  2013年   277篇
  2012年   388篇
  2011年   404篇
  2010年   222篇
  2009年   167篇
  2008年   269篇
  2007年   256篇
  2006年   225篇
  2005年   190篇
  2004年   165篇
  2003年   140篇
  2002年   107篇
  2001年   97篇
  2000年   78篇
  1999年   82篇
  1998年   33篇
  1997年   18篇
  1996年   22篇
  1995年   11篇
  1994年   9篇
  1993年   8篇
  1992年   31篇
  1991年   29篇
  1990年   25篇
  1989年   22篇
  1988年   10篇
  1987年   12篇
  1986年   5篇
  1985年   17篇
  1984年   5篇
  1983年   6篇
  1979年   5篇
  1974年   8篇
  1972年   5篇
  1971年   8篇
  1970年   4篇
  1969年   6篇
  1968年   14篇
  1967年   5篇
  1966年   4篇
排序方式: 共有4785条查询结果,搜索用时 0 毫秒
91.
We measured heating of isotonic saline by three fluid warmers in six experiments: saline at 5 °C or 20 °C delivered at 30, 50 or 100 ml.min?1. At the three flow rates, the enFLOW®, buddy lite? and ThermoSens® systems heated 5 °C saline to mean (SD) temperatures of: 41.1 (0.5) °C, 37.7 (0.6) °C and 39.1 (0.6) °C; to 40.3 (0.8) °C, 33.9 (1.6) °C and 39.3 (0.7) °C; and to 37.1 (0.8) °C, 24.0 (1.3) °C and 37.6 (1.0) °C, respectively, p < 0.0001 for each experiment. The mean (SD) times taken to heat 5 °C saline were: 16.6 (1.7) s, 258.4 (58.9) s and 134.2 (79.6) s; 16.9 (1.8) s, 256.2 (62.2) s and 182.5 (74.5) s; and 21.5 (1.5) s, 275.9 (49.3) s and 313.5 (18.0) s, respectively, p < 0.0003 for each experiment. The results for saline at 20 °C were similar. The enFLOW system heated saline above 36 °C faster than the ThermoSens system, whereas the buddy lite often failed to achieve 36 °C.  相似文献   
92.
93.
94.
95.
Pituitary apoplexy is a rare but potentially life-threatening clinical syndrome caused by the sudden enlargement of a pituitary adenoma secondary to hemorrhage or infarction. Pituitary apoplexy after cardiac surgery is a very rare perioperative complication. Factors associated with open heart surgery that may lead to pituitary apoplexy include hemodynamic instability during cardiopulmonary bypass and systemic heparinization. We report a case of pituitary apoplexy after mitral valvuloplasty with cardiopulmonary bypass. After early pituitary tumor resection and hormonal replacement therapy, the patient made a full recovery.  相似文献   
96.
97.
Introduction: Extracorporeal membrane oxygenation (ECMO) is widely used to treat respiratory distress during cardiac or respiratory arrest; moreover, its use is being extended to a wide variety of clinical fields. In this study we assess the utility of ECMO in the management of airway obstruction.Patients and Methods: 15 patients underwent ECMO for airway obstruction. We retrospectively analyzed and evaluated the feasibility of ECMO in the treatment of airway problems.Results: Seven patients received ECMO to facilitate respiration and promote stability during trachea surgery. In six cases ECMO ceased immediately following the operation; in the remaining case ECMO cessation was delayed due to post-operative ARDS. In three cases emergency ECMO was used in response to respiratory arrest; two patients died. In five cases ECMO was emergently inserted to prevent death, following airway blockade by massive hemoptysis. One patient was not discharged from the intensive care unit. Another patient was transferred to a general ward but died from other causes.Conclusion: ECMO is useful during anesthesia in patients at high risk of airway blockade, for example due to endobronchial bleeding, and during complex thoracic surgery. ECMO confers a safer environment during airway surgery, and its complication rate is acceptable.  相似文献   
98.

PURPOSE

This study aimed to investigate the efficacy of cleaning solutions on saliva-contaminated zirconia in comparison to air-abrasion in terms of resin bonding.

MATERIALS AND METHODS

For saliva-contaminated airabraded zirconia, seven cleaning methods)-no contamination (NC), water-spray rinsing (WS), additional airabrasion (AA), and cleaning with four solutions (Ivoclean [IC]; 1.0 wt% sodium dodecyl sulfate [SDS], 1.0 wt% hydrogen peroxide [HP], and 1.0 wt% sodium hypochlorite [SHC])-were tested. The zirconia surfaces for each group were characterized using various analytical techniques. Three bonded resin (Panavia F 2.0) cylinders (bonding area: 4.5 mm2) were made on one zirconia disk specimen using the Ultradent jig method [four disks (12 cylinders)/group; a total of 28 disks]. After 5,000 thermocycling, all specimens were subjected to a shear bond strength test with a crosshead speed of 1.0 mm/minute. The fractured surfaces were observed using an optical and scanning electron microscope (SEM).

RESULTS

Contact angle measurements showed that groups NC, AA, IC, and SHC had hydrophilic surfaces. The X-ray photoelectron spectroscopy (XPS) analysis showed similar elemental distributions between group AA and groups IC and SHC. Groups IC and SHC showed statistically similar bond strengths to groups NC and AA (P>.05), but not groups SDS and HP (P<.05). For groups WS, SDS, and HP, blister-like bubble formations were observed on the surfaces under SEM.

CONCLUSION

Within the limitations of this in vitro study, some of the cleaning solutions (IC or SHC) were effective in removing saliva contamination and enhancing the resin bond strength.  相似文献   
99.
[Purpose] The purpose of this study was to evaluate the effects of constrained weight shift induced by shoe lift beneath the unaffected lower extremity, on balance functions and electromyography of the affected lower extremity of stroke patients. [Subjects and Methods] Twelve patients with unilateral stroke were recruited as volunteers for this study. The subjects were repeatedly measured in a randomized order under three conditions: no-shoe lift, and shoe lifts of 5 mm and 10 mm heights beneath the unaffected lower extremity. [Results] Standing with a 10 mm shoe lift for the unaffected lower extremity decreased the mean velocity of mediolateral sway compared to no-shoe lift. Regarding the velocity of anteroposterior sway, standing with 5 mm and 10 mm shoe lifts decreased the mean velocity of anteroposterior sway. The muscle activation of the affected lower extremity was not significantly different among the no-shoe lift, 5 mm shoe lift and 10 mm shoe lift conditions; however, the muscle activities of the rectus femoris, biceps femoris, tibialis anterior, and medial gastrocnemius of the affected lower extremity progressively improved with increasing height of the shoe lift. [Conclusion] A constrained weight shift to the affected side elicited by a shoe insole of 10 mm height on the unaffected side can improve the static standing balance of stroke patients, and it resulted in 14–24% increases in the muscle activities of the affected leg.Key words: Constrained weight shift, Stroke, Balance  相似文献   
100.
Viscum album coloratum (Korean mistletoe) is a semi-parasitic plant that grows on various trees and has a variety of biological functions such as immunomodulation, apoptosis, and anti-tumor activity. In this study, we investigated the effects of Korean mistletoe extract (KME) on lifespan in experimental models using Caenorhabditis elegans and Drosophila melanogaster. Supplementation of KME at 50 μg/ml extended the mean survival time by 9.61 and 19.86 % in worms and flies, respectively. The longevity benefit of KME was not due to reduced feeding, reproduction, and/or locomotion in flies and worms. The supplementation of KME also did not increase resistance to various stresses including heat shock, oxidative, or starvation stresses. Furthermore, KME did not further extend the lifespan of flies fed a dietary restricted diet but did increase the expression of Sir2, one of the target genes of dietary restriction, suggesting that KME may function as a putative dietary restriction mimetic. These results also suggest that the longevity promoting effects of KME may be an example of mild stress-induced hormesis.  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