全文获取类型
收费全文 | 553篇 |
免费 | 21篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 19篇 |
妇产科学 | 13篇 |
基础医学 | 44篇 |
口腔科学 | 22篇 |
临床医学 | 59篇 |
内科学 | 106篇 |
皮肤病学 | 3篇 |
神经病学 | 35篇 |
特种医学 | 5篇 |
外科学 | 163篇 |
综合类 | 11篇 |
一般理论 | 1篇 |
预防医学 | 20篇 |
眼科学 | 6篇 |
药学 | 31篇 |
中国医学 | 2篇 |
肿瘤学 | 14篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 9篇 |
2021年 | 22篇 |
2020年 | 15篇 |
2019年 | 13篇 |
2018年 | 12篇 |
2017年 | 13篇 |
2016年 | 21篇 |
2015年 | 27篇 |
2014年 | 21篇 |
2013年 | 29篇 |
2012年 | 68篇 |
2011年 | 50篇 |
2010年 | 22篇 |
2009年 | 28篇 |
2008年 | 46篇 |
2007年 | 32篇 |
2006年 | 18篇 |
2005年 | 24篇 |
2004年 | 25篇 |
2003年 | 21篇 |
2002年 | 11篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1979年 | 3篇 |
1976年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有580条查询结果,搜索用时 0 毫秒
71.
Maternal smoking is considered to be a risk factor for low birth weight. It is hypothesized that alteration in leptin concentration may be associated with reduced fetal growth. In this study, we assess the effect of smoking during pregnancy on maternal and neonatal serum leptin concentrations, and also on breast milk leptin levels. When the infants were brought to routine physical examination at 7 days old, blood samples and breast milk specimens were taken for leptin measurement from mothers who smoked during pregnancy and their newborns. Nonsmoking mothers and their infants were recruited randomly over the same period as a control group. Maternal age, number of pregnancy, weight of the mothers, birth weight, and gestational age of the infants were similar in both groups (p > 0.05). There was no significant difference between groups in maternal serum and breast milk leptin levels (p = 0.14 and p = 0.96, respectively). However, serum leptin levels were found significantly lower in neonates born to smoking mothers compared with infants born to nonsmoking mothers (p = 0.02). Our findings suggest that maternal smoking dose not have an effect on maternal serum and breast milk leptin levels but decreases neonatal serum leptin concentration independent of birth weight. 相似文献
72.
BACKGROUND/AIMS: Gangrenous cholecystitis, empyema, gallbladder perforation, and biliary peritonitis are severe complications of acute cholecystitis associated with increased morbidity and mortality. This study aimed to evaluate perioperative factors associated with complications of acute cholecystitis. METHODOLOGY: Between January 1993 and October 2000, we performed cholecystectomy in 368 patients with acute cholecystitis. All perioperative data were collected on age, sex, medical history, symptoms, laboratory tests, ultrasound, operative and microbiological findings, morbidity and mortality. RESULTS: There were 305 cases (83%) of acute uncomplicated cholecystitis, 26 (7.1%) of gangrenous cholecystitis, 23 (6.3%) of empyema of the gallbladder, 12 (3.3%) of gallblader perforation, and 2 (0.5%) emphysematous cholecystitis. Risk factors for complicated cholecystitis included male gender, advanced age, associated diseases, temperature above 38 degrees C, and white blood cell count on admission greater than 18,000. Laparoscopic cholecystectomy was attempted on 36 patients (11.8%) with uncomplicated and seven patients (11.1%) with complicated acute cholecystitis. The conversion rate to open cholecystectomy was 19.4% for uncomplicated cases, 28.6% for complicated cases. There were no differences in operative complications between complicated and uncomplicated cases, however, length of hospital stay, postoperative morbidity and mortality were significantly higher in complicated cases. CONCLUSIONS: Sex (male), advanced age, presence of associated disease, high temperature (> 38 degrees C) and leukocytosis are all remarkable risk factors inducing complications in acute cholecystitis. Laparoscopic cholecystectomy can be performed with success in uncomplicated cases. 相似文献
73.
Tabari AM 《Journal of telemedicine and telecare》2007,13(6):274-276
Many developing countries still rely on conventional hard copy images to transfer information among physicians. We have developed a low-cost alternative method of printing computerised tomography (CT) scan images where there is no dedicated camera. A digital camera is used to photograph images from the CT scan screen monitor. The images are then transferred to a PC via a USB port, before being printed on glossy paper using an inkjet printer. The method can be applied to other imaging modalities like ultrasound and MRI and appears worthy of emulation elsewhere in the developing world where resources and technical expertise are scarce. 相似文献
74.
75.
76.
77.
78.
A bivariate autoregressive Poisson model and its application to asthma-related emergency room visits
There are no gold standard methods that perform well in every situation when it comes to the analysis of multiple time series of counts. In this paper, we consider a positively correlated bivariate time series of counts and propose a parameter-driven Poisson regression model for its analysis. In our proposed model, we employ a latent autoregressive process, AR(p) to accommodate the temporal correlations in the two series. We compute the familiar maximum likelihood estimators of the model parameters and their standard errors via a Bayesian data cloning approach. We apply the model to the analysis of a bivariate time series arising from asthma-related visits to emergency rooms across the Canadian province of Ontario. 相似文献
79.
Abdulkadir Tepeler Tolga Akman Mesrur Selcuk Silay Muzaffer Akcay Cevper Ersoz Senad Kalkan Abdullah Armagan Kemal Sarica 《Urological research》2014,42(3):275-279
The micro-percutaneous nephrolithotomy (microperc) is a recently introduced percutaneous nephrolithotomy (PNL) technique that is performed through a 4.8Fr all-seeing needle. We aimed to measure the intrarenal pelvic pressure (IPP) during microperc and compare it with the levels of conventional PNL. A total of 20 patients with 1- to 3-cm renal calculi resistant to shock wave lithotripsy were treated either with microperc (Group-1, n: 10) or conventional PNL (Group-2, n: 10) by the same surgical team. The IPP was measured during different stages (entrance into the collecting system, stone fragmentation, and before termination) of the procedures by an urodynamic machine using the 6Fr ureteral catheter. All the variables were statistically compared between the two groups. The demographic values of the patients were similar. The operation time and duration of hospitalization were significantly prolonged in conventional PNL group (p = 0.034, p = 0.01, respectively). The mean drop in hematocrit levels was significantly lower in microperc group (3.5 ± 1.5 vs. 1.8 ± 0.8; p = 0.004). The IPP was significantly higher in microperc group during all steps of the procedure. The highest level of the IPP was measured as 30.3 ± 3.9 and 20.1 ± 3.1 mmHg in Group 1 and Group 2, respectively (p < 0.0001). However, the complication and success rates were found comparable. In conclusion, we demonstrate that the level of IPP is significantly increased during microperc compared to conventional PNL. Microperc should be used cautiously in cases with impaired drainage of the collecting system. 相似文献
80.