全文获取类型
收费全文 | 16436篇 |
免费 | 1042篇 |
国内免费 | 83篇 |
专业分类
耳鼻咽喉 | 148篇 |
儿科学 | 345篇 |
妇产科学 | 247篇 |
基础医学 | 2306篇 |
口腔科学 | 357篇 |
临床医学 | 1677篇 |
内科学 | 3496篇 |
皮肤病学 | 202篇 |
神经病学 | 1758篇 |
特种医学 | 640篇 |
外科学 | 2516篇 |
综合类 | 100篇 |
一般理论 | 36篇 |
预防医学 | 1131篇 |
眼科学 | 200篇 |
药学 | 1298篇 |
中国医学 | 22篇 |
肿瘤学 | 1082篇 |
出版年
2023年 | 107篇 |
2022年 | 188篇 |
2021年 | 413篇 |
2020年 | 294篇 |
2019年 | 444篇 |
2018年 | 459篇 |
2017年 | 343篇 |
2016年 | 450篇 |
2015年 | 437篇 |
2014年 | 645篇 |
2013年 | 869篇 |
2012年 | 1248篇 |
2011年 | 1270篇 |
2010年 | 693篇 |
2009年 | 646篇 |
2008年 | 1054篇 |
2007年 | 1124篇 |
2006年 | 1035篇 |
2005年 | 988篇 |
2004年 | 880篇 |
2003年 | 767篇 |
2002年 | 807篇 |
2001年 | 131篇 |
2000年 | 87篇 |
1999年 | 117篇 |
1998年 | 148篇 |
1997年 | 150篇 |
1996年 | 130篇 |
1995年 | 100篇 |
1994年 | 106篇 |
1993年 | 105篇 |
1992年 | 81篇 |
1991年 | 69篇 |
1990年 | 65篇 |
1989年 | 53篇 |
1988年 | 46篇 |
1987年 | 44篇 |
1986年 | 55篇 |
1985年 | 59篇 |
1984年 | 51篇 |
1983年 | 61篇 |
1982年 | 66篇 |
1981年 | 69篇 |
1980年 | 65篇 |
1979年 | 33篇 |
1978年 | 41篇 |
1977年 | 46篇 |
1976年 | 34篇 |
1975年 | 28篇 |
1974年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Erik D Skarsgard Ying C MacNab Zhenguo Qiu Ruth Little Shoo K Lee 《Journal of perinatology》2005,25(5):315-319
OBJECTIVE: Outcomes analysis in congenital diaphragmatic hernia (CDH) requires a validated risk-adjustment tool. The purpose of this study was to use the Canadian Neonatal Network (CNN) database to validate the Score for Neonatal Acute Physiology, Version II (SNAP-II) for prediction of mortality among CDH infants admitted to a neonatal intensive care unit (NICU), and to compare this to the predictive equation recently developed by the Congenital Diaphragmatic Hernia Study Group (CDHSG). STUDY DESIGN: Infants with CDH in the CNN database were identified. Bivariate and multivariable logistic regression models were used to identify risk factors predictive of mortality. Model predictive performance and calibration were assessed using the area under the receiver operator characteristic curve and the technique of Hosmer-Lemeshow, respectively, and compared with the CDHSG predictive equation. RESULTS: There were 88 patients with CDH among 19,507 admissions to CNN hospitals. The mortality rate among CDH patients surviving to NICU admission was 17%, and 12.5% received extracorporeal membrane oxygenation therapy. Gestational age and admission SNAP-II score predicted mortality. Model predictive performance and calibration were optimized with these variables combined. The CDHSG equation was equally predictive of mortality, but was only marginally calibrated. CONCLUSIONS: SNAP-II is highly predictive of mortality among patients with CDH, and can be used to risk-adjust these patients. 相似文献
22.
23.
Anthony M Dart Jan Erik Otterstad Bridget-Anne Kirwan John D Parker Sophie de Brouwer Philip A Poole-Wilson Jacobus Lubsen 《European journal of echocardiography》2007,8(4):275-283
AIMS: To evaluate the relationship between echocardiographic cardiac function and outcome in patients with stable symptomatic angina. METHODS: Baseline echo left ventricular ejection fraction and volume data measured in a central laboratory was available for 7016 patients (92% of the total) participating in the ACTION trial (A Coronary disease Trial Investigating Outcome with Nifedipine GITS). Ejection fraction was also measured by investigators. Evaluation of the different echocardiographic variables was based on adjusted hazard ratios comparing the unfavourable limit of the 90% range of the variable concerned to the favourable limit. RESULTS: The centrally measured ejection fraction was the most powerful predictor of all-cause death (adjusted hazard ratio=2.5), myocardial infarction, any stroke or transient ischaemic attack and overt heart failure (adjusted hazard ratio=4.5). The addition of either end systolic volume or end diastolic volume to ejection fraction did not materially affect the power of prediction. Compared to the central ejection fraction measurement, the investigator-measured ejection fraction was a less powerful predictor for all outcomes considered. CONCLUSION: Routine echocardiography carefully analysed by standardised methods provides useful prognostic information in patients with stable angina, including for total mortality. 相似文献
24.
25.
INTRODUCTION: We report successful management of aortic endograft infection without graft explantation or extra-anatomic bypass. REPORT: A 66 year-old male who had undergone endovascular repair of an aortic aneurysm presented with abdominal pain and raised inflammatory markers following embolisation of a type-2 'endoleak'. CT scanning revealed a left psoas fluid collection. Endograft infection was diagnosed. Following failure of CT-guided drainage and conservative management, surgical drainage with irrigation drain placement was undertaken with preservation of the endograft. There was no evidence of recurrent infection after follow-up at 30 months. DISCUSSION: Aortic endograft infection may be managed without endograft removal and extra-anatomic bypass. 相似文献
26.
Jan de Lange Thomas Putters Erik M Baas Johan M van Ingen 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,104(6):841-845
OBJECTIVE: The purpose of this study was to evaluate the potential benefit of an ultrasonic device in apical surgery on the outcome of treatment. STUDY DESIGN: A randomized prospective design was used in a standardized treatment protocol. Patients were allocated to treatment with an ultrasonic device (P-Max Newtron) or treatment with a bur in an otherwise similar protocol. One year after treatment the results were evaluated by 2 oral and maxillofacial surgeons who were blinded for the therapy. RESULTS: Out of a total group of 399 patients who were included in the study, adequate follow-up could be obtained in 290 patients. The overall success rate in the ultrasonic group was 80.5% and in the group treated with a bur 70.9% (P = .056). In molars, the difference in success rate was significant (P = .02). CONCLUSION: The use of an ultrasonic device in apical surgery improved the outcome of treatment. In molars this effect was significant. 相似文献
27.
手术致肾盂输尿管交界部闭锁的再手术治疗 总被引:1,自引:0,他引:1
目的:探讨复杂性肾窦内肾盂结石取石术后肾盂输尿管交界部闭锁的原因和再手术治疗方法。方法:对于9例复杂性肾窦内肾盂结石取石术后致肾盂输尿管交界部闭锁患者行输尿管和肾下极侧侧吻合术.并采用双J管和肾造瘘管双重支撑及引流。结果:9例手术均获得成功。随访6~36个月,IVU示9例患者经再手术所重建的上尿路均引流通畅,肾盂肾盏积水明显缓解,肾功能明显改善。结论:输尿管与肾下极吻合是肾盂输尿管交界部闭锁再手术治疗的较好方法,而双J管和肾造瘘管双重支撑引流则是手术成功的关键。 相似文献
28.
Ordinary surgical rubber gloves are penetrated by methylmethacrylate monomer (MMA) in less than 1 minute, as demonstrated by gas chromatographic measurements. A three-layered PVP glove, 0.07 mm thick - consisting of an outer layer of polyethylene, an intermediary layer of ethylene vinyl alcohol copolymer, and an inner layer of polyethylene - was impervious for 20 minutes, whereas a viton-butyl rubber glove, 0.27 mm thick, was impervious for 15 minutes.
The PVP glove is recommended to orthopedic surgeons, nurses, and other handling acrylic bone cements to avoid sensitization, and is especially recommended to persons with known contact allergy to MMA. 相似文献
The PVP glove is recommended to orthopedic surgeons, nurses, and other handling acrylic bone cements to avoid sensitization, and is especially recommended to persons with known contact allergy to MMA. 相似文献
29.
The electromyographic (EMG) interference pattern (IP) was measured in the biceps muscle of 16 normal male and 17 normal female subjects. The activity, upper centile amplitude (UCA), and the number of small segments (NSS) (defined in a companion paper) were measured from 500-msec epochs of the IP. The normal values of these features were defined separately for men and women by plotting the UCA and NSS values against activity for each epoch and defining an area on these plots, called a “cloud,” that contained more than 90% of the datum points from each study. The mean deviation of the individual datum points from the overall mean values was also calculated for each study. A study in one muscle is considered to be normal if more than 90% of the datum points from that muscle are within the normal clouds and the deviation values are within their normal range. In patients with neuropathy, the characteristic pattern was increased UCA with normal or decreased NSS. In patients with myopathy, NSS was increased and the UCA was normal or decreased. In all studies, the interpretations of the IP from the plots agreed with qualitative assessments of the IP made independently by an electromyographer. The use of these features to understand and quantitate the changes in the motor units produced by disease is demonstrated by serial studies performed in a patient with motor neuron disease. 相似文献
30.
Exercise rapidly increases eukaryotic elongation factor 2 phosphorylation in skeletal muscle of men 总被引:11,自引:6,他引:5
Adam J. Rose Christa Broholm Kristian Kiillerich Stephen G. Finn Christopher G. Proud Mark H. Rider Erik A. Richter Bente Kiens 《The Journal of physiology》2005,569(1):223-228
Protein synthesis in skeletal muscle is known to decrease during contractions but the underlying regulatory mechanisms are unknown. Here, the effect of exercise on skeletal muscle eukaryotic elongation factor 2 (eEF2) phosphorylation, a key component in protein translation machinery, was examined. Eight healthy men exercised on a cycle ergometer at a workload eliciting ∼67% peak pulmonary oxygen consumption with skeletal muscle biopsies taken from the vastus lateralis muscle at rest as well as after 1, 10, 30, 60 and 90 min of exercise. In response to exercise, there was a rapid (i.e. < 1 min) 5- to 7-fold increase in eEF2 phosphorylation at Thr56 that was sustained for 90 min of continuous exercise. The in vitro activity of skeletal muscle eEF2 kinase was not altered by exercise indicating that the increased activity of eEF2 kinase to eEF2 is not mediated by covalent mechanisms. In support of this, the increase in AMPK activity was temporally unrelated to eEF2 phosphorylation. However, skeletal muscle eEF2 kinase was potently activated by Ca2 + –calmodulin in vitro , suggesting that the higher eEF2 phosphorylation in working skeletal muscle is mediated by allosteric activation of eEF2 kinase by Ca2 + signalling via calmodulin. Given that eEF2 phosphorylation inhibits eEF2 activity and mRNA translation, these findings suggest that the inhibition of protein synthesis in contracting skeletal muscle is due to the Ca2 + -induced stimulation of eEF2 kinase. 相似文献