全文获取类型
收费全文 | 77246篇 |
免费 | 5243篇 |
国内免费 | 1636篇 |
专业分类
耳鼻咽喉 | 3106篇 |
儿科学 | 893篇 |
妇产科学 | 1512篇 |
基础医学 | 1896篇 |
口腔科学 | 3141篇 |
临床医学 | 7159篇 |
内科学 | 7357篇 |
皮肤病学 | 699篇 |
神经病学 | 2541篇 |
特种医学 | 1269篇 |
外国民族医学 | 20篇 |
外科学 | 26436篇 |
综合类 | 10388篇 |
现状与发展 | 6篇 |
一般理论 | 2篇 |
预防医学 | 2778篇 |
眼科学 | 5249篇 |
药学 | 3044篇 |
175篇 | |
中国医学 | 862篇 |
肿瘤学 | 5592篇 |
出版年
2024年 | 265篇 |
2023年 | 2077篇 |
2022年 | 3179篇 |
2021年 | 4187篇 |
2020年 | 4146篇 |
2019年 | 3543篇 |
2018年 | 3370篇 |
2017年 | 2912篇 |
2016年 | 2914篇 |
2015年 | 2955篇 |
2014年 | 5829篇 |
2013年 | 5430篇 |
2012年 | 4403篇 |
2011年 | 4631篇 |
2010年 | 3715篇 |
2009年 | 3503篇 |
2008年 | 3365篇 |
2007年 | 3354篇 |
2006年 | 2928篇 |
2005年 | 2558篇 |
2004年 | 2209篇 |
2003年 | 1786篇 |
2002年 | 1404篇 |
2001年 | 1330篇 |
2000年 | 1139篇 |
1999年 | 1043篇 |
1998年 | 857篇 |
1997年 | 811篇 |
1996年 | 604篇 |
1995年 | 492篇 |
1994年 | 435篇 |
1993年 | 350篇 |
1992年 | 295篇 |
1991年 | 293篇 |
1990年 | 198篇 |
1989年 | 193篇 |
1988年 | 194篇 |
1987年 | 194篇 |
1986年 | 153篇 |
1985年 | 170篇 |
1984年 | 159篇 |
1983年 | 103篇 |
1982年 | 109篇 |
1981年 | 96篇 |
1980年 | 76篇 |
1979年 | 44篇 |
1978年 | 33篇 |
1977年 | 32篇 |
1976年 | 24篇 |
1975年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Cortes RA Keller RL Townsend T Harrison MR Farmer DL Lee H Piecuch RE Leonard CH Hetherton M Bisgaard R Nobuhara KK 《Journal of pediatric surgery》2005,40(1):36-46
Background/Purpose
Fetal tracheal occlusion (TO) was developed in an attempt to enhance prenatal lung growth and improve survival in fetuses with severe congenital diaphragmatic hernia (CDH). We conducted a randomized, controlled clinical trial in 24 fetuses with severe left CDH (liver herniated into the thorax and low lung-to-head ratio) to compare survival after endoscopic fetal TO vs standard perinatal care (control) and prospectively followed up the 16 survivors (9 control, 7 TO) to compare neurodevelopmental, respiratory, surgical, growth, and nutritional outcomes.Methods
At 1 and 2 years old, subjects underwent evaluation consisting of medical and neurological history and physical, developmental testing, nutritional assessment, oxygen saturation and pulmonary function testing, chest radiograph, and echocardiogram. Growth and developmental measures were corrected for prematurity. Data were analyzed by Mann-Whitney rank sum test, Fisher's Exact test, and logistic and linear regression.Results
Infants with TO were significantly more premature at birth (control vs TO, 37.4 ± 1.0 vs 31.1 ± 1.7 weeks; P < .01). Growth failure (z score for weight <2 SDs below mean) was severe in both groups at 1 year of age (control vs TO, 56% vs 86%; P = .31). There was considerable catch-up growth by age 2 years (growth failure: control vs TO, 22% vs 33%; P = .19). There were no differences in other growth parameters. There were also no differences in neurodevelopmental outcome at 1 and 2 years. Supplemental oxygen at hospital discharge was a significant predictor of worse neurodevelopmental outcome at 1 and 2 years old (P = .05 and P = .02, respectively). Hearing loss requiring amplification has been diagnosed in 44% of the group (control vs TO, 44% vs 43%; P = 1.0).Conclusions
In this group of infants with severe CDH, there were no differences in outcome at 2 years old despite significant prematurity in the TO group. Oxygen supplementation at hospital discharge identified the most vulnerable group with respect to neurodevelopmental outcome, but all infants had significant growth failure, and hearing impairment is a substantial problem in this population. Severe CDH carries significant risk of chronic morbidity. 相似文献952.
Purpose:
This blinded study evaluates the N2O concentration variations in an ambulatory surgery centre using a small, simple on-line trace gas concentration monitor (GasFinder™ [Medair AB, Delsbo, Sweden]).Scope:
Thirty-seven day surgical sessions using standardised anaesthesia with propofol/fentanyl induction and sevoflurane/N2O with larynx mask. Five of 37 time-weighted averages (TWA) were greater than 25 ppm but less than 100. Peak registered concentrations reached 2000 ppm. Eleven sessions showed peak values higher than 100 ppm (range 13-1693).Conclusions:
This simple, on-line N2O monitor is a useful tool for detecting deviations from strict gas hygiene. 相似文献953.
Suzuki S Suzuki N Hattori A Hayashibe M Konishi K Kakeji Y Hashizume M 《The international journal of medical robotics + computer assisted surgery : MRCAS》2005,1(4):80-88
Robotic systems are increasingly being incorporated into general laparoscopic and thoracoscopic surgery to perform procedures such as cholecystectomy and prostatectomy. Robotic assisted surgery allows the surgeon to conduct minimally invasive surgery with increased accuracy and with potential benefits for patients. However, current robotic systems have their limitations. These include the narrow operative field of view, which can make instrument manipulation difficult. Current robotic applications are also tailored to specific surgical procedures. For these reasons, there is an increasing demand on surgeons to master the skills of instrument manipulation and their surgical application within a controlled environment. This study describes the development of a surgical simulator for training and mastering procedures performed with the da Vinci surgical system. The development of a tele-surgery simulator and the construction of a training center are also described, which will enable surgeons to simulate surgery from or in remote places, to collaborate over long distances, and for off-site expert assistance. 相似文献
954.
955.
Hayashibe M Suzuki N Hashizume M Kakeji Y Konishi K Suzuki S Hattori A 《The international journal of medical robotics + computer assisted surgery : MRCAS》2005,1(2):76-85
Recently, some useful robotic surgical systems have been developed and applied in many surgical situations. Systems such as the da Vinci surgical system of Intuitive Surgical Inc., which facilitates minimally invasive surgery with increased dexterity, are commercially available. Preoperative simulation and planning of surgical robot setups should accompany advanced robotic surgery if their advantages are to be further pursued. Feedback from the planning system will play an essential role in computer-aided robotic surgery in addition to preoperative detailed geometric information from patient CT/MRI images. Surgical robot setup simulation systems for appropriate trocar site placement have been developed especially for abdominal surgery. The motion of the surgical robot can be simulated and rehearsed with kinematic constraints at the trocar site, and the inverse-kinematics of the robot. Results from simulation using clinical patient data verify the effectiveness of the proposed system. 相似文献
956.
Effects of autotransfusion of mediastinal shed blood on biochemical markers of myocardial damage in coronary surgery 总被引:2,自引:0,他引:2
Pleym H Tjomsland O Asberg A Lydersen S Wahba A Bjella L Dale O Stenseth R 《Acta anaesthesiologica Scandinavica》2005,49(9):1248-1254
BACKGROUND: Previous studies have shown conflicting results regarding the effect of autotransfusion of mediastinal shed blood after coronary artery bypass grafting (CABG) on the serum levels of myocardial band (MB) isoenzymes of creatine kinase (CK-MB) and cardiac troponins. The effect of autotransfusion on serum levels of human heart fatty acid binding protein (H-FABP), another marker of myocardial necrosis, has not been studied. The aim of the present study was to investigate the effects of autotransfusion of mediastinal shed blood on the serum levels of CK-MB, cardiac troponin T (cTnT), and H-FABP after uncomplicated primary CABG. METHODS: Fifty patients were randomized to post-operative autotransfusion of mediastinal shed blood or no autotransfusion. Blood samples for the analysis of the biochemical markers of myocardial damage were drawn pre-operatively and 1, 4, 12, 24, 48, and 72 h after the termination of cardiopulmonary bypass. Samples from the mediastinal shed blood were collected after 1 and 4 h. RESULTS: The levels of the biochemical markers of myocardial injury were all markedly elevated in mediastinal shed blood. Autotransfusion did not significantly affect the serum levels of cTnT or H-FABP. However, during the early post-operative hours, there was a trend towards a higher level of cTnT and H-FABP in the autotransfusion group. During the first 24 h after surgery, the autotransfusion group had a significantly higher serum level of CK-MB. CONCLUSION: Post-operative autotransfusion of mediastinal shed blood may contribute to elevated serum levels of biochemical markers of myocardial injury. 相似文献
957.
958.
OBJECTIVE: To report an unusual and asymptomatic cause of cord compression treated surgically with good clinical outcome. METHODS AND MATERIAL: We report a case of extradural arachnoid cyst in the thoracic region and review the literature on the clinical, neuroradiologic and therapeutic features. RESULTS: A 17-year-old man, with unremarkable past medical history was referred to our institution of Neurosurgery, CHU Mohammed-VI, Marrakech, with progressive spastic paraparesis. Magnetic resonance imaging (MRI) showed a posterior extradural cystic lesion in the thoracic region from T6-T7 thoracic vertebra. The cyst was completely removed by posterior approach. An arachnoid cyst was confirmed at the histological study. Neurological symptoms improved after surgery. CONCLUSION: Given its infrequency, the diagnosis of arachnoid cyst should be suspected when a cystic lesion causes cord compression. Surgery is the treatment of choice, providing good clinical outcome. 相似文献
959.
Michael D. Lara M.D. Matthew T. Baker M.D. Christopher J. Larson PA-C R.D. Michelle A. Mathiason M.S. Pamela J. Lambert R.N. Shanu N. Kothari M.D. 《Surgery for obesity and related diseases》2005,1(1):597-21
BACKGROUND: There is no consensus regarding the optimal rate of follow-up in the post-bariatric surgery patient population. METHODS: The records of all patients who underwent laparoscopic Roux-en-Y gastric bypass from 2001 to 2003 were reviewed. Using patient zip codes, travel distances were calculated between the patients' places of residence and our clinic. Patients were then assigned to 1 of 3 cohorts according to the following distances: (1) < 50 miles, (2) 50 to 100 miles, and (3) > 100 miles. Patient compliance with follow-up appointments at 3 weeks, 3 months, 6 months, 9 months, and 12 months was analyzed. Linear trends were identified using the Mantel-Haenszel test. Age and sex were analyzed as possible predictors of compliance using the chi(2) test. P values < .05 were considered statistically significant. RESULTS: The study group comprised 150 patients (127 females and 23 males). The 3 cohorts contained 115, 21, and 14 patients, respectively. All patients in each cohort were compliant with the 3-week follow-up appointment. Although there were differences in compliance between cohorts at each of the remaining appointments, only the 9-month (70.3% vs 61.9% vs 35.7%) visit showed statistical significance (P = .035). The 6-month visit trended toward significance (85.2% vs 76.2% vs 64.3%; P = .088). Males were more likely to be compliant with the 12-month follow-up (P = .040). When controlling for sex, travel distance was also a predictor of compliance at this follow-up visit (P = .024). Age was not predictive of compliance (P = .827). CONCLUSION: Based on our findings, we conclude that travel distance from the clinic does not significantly affect compliance at the initial follow-up, 3-month, and 12-month appointments. However, distance does tend to affect compliance at the 6-month appointment and significantly affects compliance at the 9-month appointment. Males are more likely to be compliant at the 12 month follow-up visit. We must continue to strive for 100% follow-up in our post-bariatric surgery patients. 相似文献
960.
Comparison of propofol/remifentanil and sevoflurane/remifentanil for maintenance of anaesthesia for elective intracranial surgery 总被引:13,自引:0,他引:13
Background. Propofol and sevoflurane are suitable agents formaintenance of anaesthesia during neurosurgical procedures.We have prospectively compared these agents in combination withthe short-acting opioid, remifentanil. Methods. Fifty unpremedicated patients undergoing elective craniotomyreceived remifentanil 1 µg kg1 followed by an infusioncommencing at 0.5 µg kg1 min1 reducing to0.25 µg kg1 min1 after craniotomy. Anaesthesiawas induced with propofol, and maintained with either a target-controlledinfusion of propofol, minimum target 2 µg ml1 orsevoflurane, initial concentration 2%ET. Episodes of mean arterialpressure (MAP) more than 100 mm Hg or less than 60 mm Hg formore than 1 min were defined as hypertensive or hypotensiveevents, respectively. A surgical assessment of operating conditionsand times to spontaneous respiration, extubation, obey commandsand eye opening were recorded. Drug acquisition costs were calculated. Results. Twenty-four and twenty-six patients were assigned topropofol (Group P) and sevoflurane anaesthesia (Group S), respectively.The number of hypertensive events was comparable, whilst morehypotensive events were observed in Group S than in Group P(P=0.053, chi-squared test). As rescue therapy, more labetolol[45 (33) vs 76 (58) mg, P=0.073] and ephedrine [4.80 (2.21)vs 9.78 (5.59) mg, P=0.020] were used in Group S. Between groupdifferences in recovery times were small and clinically unimportant.The combined hourly acquisition costs of hypnotic, analgesic,and vasoactive drugs appeared to be lower in patients maintainedwith sevoflurane than with propofol. Conclusion. Propofol/remifentanil and sevoflurane/remifentanilboth provided satisfactory anaesthesia for intracranial surgery. 相似文献