全文获取类型
收费全文 | 923014篇 |
免费 | 60518篇 |
国内免费 | 1670篇 |
专业分类
耳鼻咽喉 | 12052篇 |
儿科学 | 29973篇 |
妇产科学 | 22073篇 |
基础医学 | 141640篇 |
口腔科学 | 25056篇 |
临床医学 | 81171篇 |
内科学 | 182409篇 |
皮肤病学 | 21956篇 |
神经病学 | 69015篇 |
特种医学 | 32292篇 |
外国民族医学 | 171篇 |
外科学 | 131823篇 |
综合类 | 15743篇 |
现状与发展 | 2篇 |
一般理论 | 221篇 |
预防医学 | 71276篇 |
眼科学 | 20564篇 |
药学 | 69249篇 |
3篇 | |
中国医学 | 2996篇 |
肿瘤学 | 55517篇 |
出版年
2021年 | 8665篇 |
2019年 | 9053篇 |
2018年 | 14814篇 |
2017年 | 10677篇 |
2016年 | 11374篇 |
2015年 | 12671篇 |
2014年 | 15593篇 |
2013年 | 23997篇 |
2012年 | 35652篇 |
2011年 | 36635篇 |
2010年 | 20145篇 |
2009年 | 17511篇 |
2008年 | 32972篇 |
2007年 | 35467篇 |
2006年 | 34681篇 |
2005年 | 33115篇 |
2004年 | 31876篇 |
2003年 | 29773篇 |
2002年 | 28687篇 |
2001年 | 41636篇 |
2000年 | 42322篇 |
1999年 | 35182篇 |
1998年 | 8690篇 |
1997年 | 7324篇 |
1996年 | 7599篇 |
1995年 | 7210篇 |
1994年 | 6605篇 |
1992年 | 25842篇 |
1991年 | 25547篇 |
1990年 | 24773篇 |
1989年 | 24336篇 |
1988年 | 22187篇 |
1987年 | 21434篇 |
1986年 | 20376篇 |
1985年 | 19031篇 |
1984年 | 13984篇 |
1983年 | 11831篇 |
1982年 | 6555篇 |
1979年 | 12651篇 |
1978年 | 8909篇 |
1977年 | 7571篇 |
1976年 | 7177篇 |
1975年 | 8013篇 |
1974年 | 9404篇 |
1973年 | 9064篇 |
1972年 | 8522篇 |
1971年 | 7991篇 |
1970年 | 7694篇 |
1969年 | 7160篇 |
1968年 | 6525篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Denis Mariano-Goulart Laurent Déchaux Fran?ois Rouzet Eric Barbotte Charles Caderas de Kerleau Michel Rossi Dominique Le Guludec 《Journal of nuclear medicine》2007,48(9):1416-1423
This study aimed to assess the ability of global and local systolic parameters measured with gated blood-pool SPECT (GBPS) to diagnose and characterize the severity of diffuse or localized arrhythmogenic right ventricular dysplasia (ARVD). METHODS: Fifty-nine subjects with symptomatic ventricular arrhythmias were prospectively included in the study. With the International Society and Federation of Cardiology criteria for ARVD as a gold standard, these subjects were classified as subjects without ARVD (21 control subjects) and patients with localized ARVD (16 patients) or diffuse ARVD (22 patients). Right ventricular volumes, right ventricular ejection fractions (EF), the SD of local EF (sigma-EF), and the SD of the local times of end systole (sigma-TES) were computed from GBPS data and compared among the groups in the study population. RESULTS: sigma-EF did not differ between control subjects and patients with diffuse or localized ARVD. Right ventricular EF and volumes differed between patients with diffuse ARVD and control subjects, with similar areas under the receiver-operating-characteristic curves, but right ventricular EF and volumes failed to differentiate patients with localized ARVD. In contrast, sigma-TES differed between patients with diffuse or localized ARVD and control subjects. Regression analysis showed that the systolic parameter most strongly associated with the diagnosis of ARVD was sigma-TES. The probabilities of a randomly chosen patient in the diffuse ARVD group and of a randomly chosen patient in the localized ARVD group having sigma-TES values greater than that of a randomly chosen control subject were 98.5% and 96.7%, respectively. For the diagnosis of localized ARVD, a threshold of 80 ms for sigma-TES corresponded to sensitivity, specificity, and positive and negative predictive values of 100%, 81%, 80%, and 100%, respectively. CONCLUSION: With GBPS, both diffuse ARVD and localized ARVD can be accurately diagnosed by computing sigma-TES for all of the pixels on the surface of the right ventricle. 相似文献
952.
T. Randjelovic S. Dikic B. Filipovic D. Gacic D. Bilanovic N. Stanisavljevic 《Diseases of the esophagus》2007,20(3):239-246
A non-dilatable benign stricture of the esophagus is a problem for the patient and always a challenge for the surgeon. The present study is intended to provide some details of surgical technique and the physiological concept that constitutes the basis for patient selection for short-segment jejunoplasty. In this study, out of 98 patients, 91 had complex stricture of the lower, and seven of the cervical esophagus. The main cause of stenosis in 60 patients (61.2%) was gastroesophageal reflux, in 34 (34.7%) post-corrosive damage, and in three (3.0%) it was other causes. All patients were treated by three methods of jejunoplasty: group I (n=54 patients) short-segment of the jejunum; group II (n=37 pts) Roux-en-Y double tract; and group III (n=7 patients) short jejunal segment on the long vascular pedicle. Intraoperative complications occurred in 17 (17.34%) of the patients. An anastomotic leak occurred only in three (3.29%) in group I and II, and 1/98 patients (1.02%) died from mediastinitis. Follow-up of functional results for up to 36 months (average 18 months) was available in 77/97 (79.3%) hospital survivors. Fifty-seven (74%) patients are satisfied with their ability to take food, postoperative reflux was completely denied by 72 (93.5%) patients. Postvagotomy diarrhea was transient and gradually subsided over the course of the first 6 months. 相似文献
953.
F Agresta I Michelet E Candiotto N Bedin 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2007,11(2):255-257
Two cases of internal herniation through a defect in the broad ligament of the uterus are described. Both were successfully treated laparoscopically. This rare condition should be borne in mind when a middle-aged woman presents with colicky lower abdominal pain. The cause is unknown, but both congenital and acquired origins have been proposed. As far as emergency situations are concerned, laparoscopy has proven to be both a diagnostic and a therapeutic tool. 相似文献
954.
H. S. Pollinger M. D. Stegall J. M. Gloor S. B. Moore S. R. Degoey N. A. Ploeger W. D. Park H. S. Pollinger M. D. Stegall J. M. Gloor S. B. Moore S. R. Degoey N. A. Ploeger W. D. Park 《American journal of transplantation》2007,7(4):857-863
The immunologic risk associated with donor-specific antibodies (DSA) against Class II human leukocyte antigens (HLA) in kidney transplant (KTx) recipients is unclear. The aim of this study was to determine the outcome of KTx when DSA was detected only against HLA Class II. To isolate the impact of anti-Class II DSA, we retrospectively analyzed 12 KTx recipients who at baseline had a positive B-cell flow cytometric crossmatch (FXM) and a negative T-cell FXM. Using alloantibody specification analysis, 58.3% (7/12) had DSA against donor Class II and 41.7% had no demonstrable DSA. Biopsy-proven AMR occurred in 57% (4/7) in the Class II(+) group and 0% in the Class II(-) group (p > 0.05). Peritubular capillaries stained positive for C4d in 86% (6/7) of the Class II(+) patients and in 40% (2/5) of the Class II(-) patients (p > 0.05). One patient in the Class II(+) group lost their graft at 3 months to accelerated transplant glomerulopathy, while all other grafts were functioning 3-37 months posttransplant despite the persistence of anti-Class II DSA. We conclude that KTx recipients with clearly defined anti-Class II DSA are at risk for humoral rejection suggesting that desensitization and/or close posttransplant monitoring may be needed to prevent AMR. 相似文献
955.
956.
Annie Mathieu Stéphanie Mazza Dominique Petit Anne Décary Jessica Massicotte-Marquez Jacques Malo Jacques Montplaisir 《Clinical neurophysiology》2007,118(7):1538-1544
OBJECTIVE: The aim of this study was to determine whether EEG slowing is more pronounced in older than younger OSAS patients and to verify whether this cortical slowing is correlated to daytime performance, respiratory perturbation and sleep fragmentation. METHODS: Twelve young OSAS patients (mean age 38.2+/-2.0 y) and 13 older OSAS patients (mean age 62.2+/-1.9 y) along with 13 young controls (mean age 35.8+/-2.0 y) and 14 older controls (mean age 60.2+/-2.0 y) underwent a polysomnographic evaluation followed by a waking EEG recording. As a global index of cortical slowing, a ratio of slow-to-fast frequencies was calculated in all cortical regions. Daytime performance was assessed using the four choice reaction time test. RESULTS: Differences in waking EEG and in daytime performance were analyzed by ANOVAs with Group and Age as factors. Waking EEG did not yield a Group by Age interaction. OSAS patients had higher ratios across all regions than controls. Similarly, daytime performance revealed no Group by Age interaction. However, OSAS patients showed more lapses than controls and older subjects were slower than younger subjects. CONCLUSIONS: Our results indicate that age does not interact with OSAS to worsen the severity of cortical slowing, but age can add to the OSAS effect to worsen daytime performance deficits in OSAS patients. SIGNIFICANCE: The daytime performance deficits observed particularly in elderly OSAS patients warrant a careful clinical assessment of these patients to prevent accidents and injuries. 相似文献
957.
R Depprich J Handschel J Hornung U Meyer N R Kübler 《Mund-, Kiefer- und Gesichtschirurgie》2007,11(1):19-26
BACKGROUND: Fractures of the mandible are a common form of facial injury. The aetiological factors associated with mandibular fractures and the trends in these factors over a 10-year period are reported. METHODS: A retrospective survey was carried out of 724 patients presenting with a fracture of the mandible over the 10-year-period 1994-2003. Patients; records were reviewed and analyzed according to age, sex, cause of injury, anatomic site of fracture, treatment and postoperative complications. RESULTS: Over the 10-year-period the rate of mandibular fractures remained constant (mean 40,7%). There were no changes in the age group (mean 33,3 years) or in the higher prevalence in male (male-female-ratio 2,3 : 1). The major causes of fractures were assaults (38,6%) and accidental fall (27,3%). The most common fracture site was the condylar region (47,0%) followed by the angle (29,4%). Most fractures were treated by closed reduction until 2002, thereafter surgical treatment increased noticeable. The complication rate was 8,9% and the most common complications were hardware exposure and infection. CONCLUSION: Fractures of the mandible are a prevalent form of facial injury. Aetiological factors show no significant change over the 10-year-period. Complication-rate is low and will support the tendency towards surgical treatment. 相似文献
958.
We present a new simple approach for automated, non-destructive measurement of the alpha-emitting radium isotopes ((223)Ra, (224)Ra, and (226)Ra) in water based on the emanation of their respective radon daughters ((219)Rn, (220)Rn, and (222)Rn). The method combines the high adsorption uptake of MnO(2) Resin for radium (K(d)=2.4 x 10(4)ml/g) over a wide pH range with the simplicity of the activity registration using a commercial radon-in-air analyzer (RAD7, DURRIDGE Company, Inc). Radium is first adsorbed onto the MnO(2) Resin by passing a water sample through the resin packed in a gas-tight glass cartridge. The same cartridge is then connected to the radon analyzer via a simple tubing system to circulate air through the resin and a drying system. The efficiency of the proposed system is determined by running standards prepared in the same manner. Our results indicate that the efficiency for (226)Ra is >22% if both (218)Po and (214)Po counts are collected. This is comparable with typical efficiencies for alpha spectrometry but with much less sample preparation. We estimate that an MDA of 0.8 pCi/L for (226)Ra may be obtained with this new approach using a 1L water sample and less than 4h of counting. 相似文献
959.
960.