全文获取类型
收费全文 | 69666篇 |
免费 | 5327篇 |
国内免费 | 200篇 |
专业分类
耳鼻咽喉 | 938篇 |
儿科学 | 2071篇 |
妇产科学 | 1358篇 |
基础医学 | 9286篇 |
口腔科学 | 1246篇 |
临床医学 | 7550篇 |
内科学 | 13863篇 |
皮肤病学 | 844篇 |
神经病学 | 6610篇 |
特种医学 | 2456篇 |
外国民族医学 | 1篇 |
外科学 | 11449篇 |
综合类 | 1324篇 |
现状与发展 | 1篇 |
一般理论 | 53篇 |
预防医学 | 5927篇 |
眼科学 | 1195篇 |
药学 | 4429篇 |
中国医学 | 64篇 |
肿瘤学 | 4528篇 |
出版年
2023年 | 366篇 |
2022年 | 673篇 |
2021年 | 1523篇 |
2020年 | 878篇 |
2019年 | 1436篇 |
2018年 | 1784篇 |
2017年 | 1207篇 |
2016年 | 1336篇 |
2015年 | 1624篇 |
2014年 | 2281篇 |
2013年 | 3064篇 |
2012年 | 4855篇 |
2011年 | 4986篇 |
2010年 | 2808篇 |
2009年 | 2489篇 |
2008年 | 4169篇 |
2007年 | 4358篇 |
2006年 | 4243篇 |
2005年 | 4331篇 |
2004年 | 3887篇 |
2003年 | 3684篇 |
2002年 | 3357篇 |
2001年 | 960篇 |
2000年 | 844篇 |
1999年 | 900篇 |
1998年 | 787篇 |
1997年 | 636篇 |
1996年 | 570篇 |
1995年 | 529篇 |
1994年 | 495篇 |
1993年 | 452篇 |
1992年 | 702篇 |
1991年 | 597篇 |
1990年 | 553篇 |
1989年 | 532篇 |
1988年 | 516篇 |
1987年 | 452篇 |
1986年 | 460篇 |
1985年 | 449篇 |
1984年 | 388篇 |
1983年 | 374篇 |
1982年 | 340篇 |
1981年 | 358篇 |
1980年 | 289篇 |
1979年 | 351篇 |
1978年 | 285篇 |
1977年 | 243篇 |
1976年 | 220篇 |
1974年 | 234篇 |
1973年 | 268篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Anne T. Berg Shlomo Shinnar‡§ Eugene D. Shapiro Morton E. Salomon‡ Ellen F. Crain‡ W. Allen Hauser§ 《Epilepsia》1995,36(4):334-341
Summary We conducted a matched casecontrol study to identify risk factors for first febrile seizures, with special emphasis on characteristics of the acute illness episode. Cases were identified through hospital emergency departments; controls were identified through outpatient clinics and emergency departments. Sixtynine children with first febrile seizures and no history of previous unprovoked seizures were matched for age (±6 months), site of routine pediatric care, and date of visit (±weeks) with 1 or 2 febrile controls who had no history of previous febrile or unprovoked seizures. Medical records for the index visit were reviewed, and parents were interviewed by telephone. Illness characteristics examined included height of temperature, type of underlying illness, contact with a physician during the illness but before the index visit, and use of acetaminophen or decongestants. Family history of febrile and of unprovoked seizures, sociodemographic characteristics, daycare use, and selected preand perinatal variables were also studied. On multivariable analysis, significant independent risk factors were height of temperature, history of febrile seizures in a firstor in a higher degree relative. Gastroenteritis as the underlying illness had a significant inverse (i.e., protective) association with febrile seizures. Maternal smoking during pregnancy was a marginally significant predictor of febrile seizures. 相似文献
102.
PURPOSETo demonstrate the spectrum of CT and MR imaging findings in patients with Wegener granulomatosis and to determine how often these findings could be attributed to either direct extension from paranasal or orbital disease sites, remote granulomas, or central nervous system (CNS) vasculitis.METHODSWe retrospectively reviewed the CT or MR studies of 15 patients with Wegener granulomatosis.RESULTSAbnormal findings were seen in 7 patients (5 examined with MR imaging, 2 with CT). Findings included dural thickening and contrast enhancement (3 patients), infarcts (2 patients), regions of hyperintense signal on T2-weighted MR images (2 patients), and abnormal MR signal in the brain stem (2 patients). Three patients with imaging findings of dural enhancement and thickening were thought to have remote granulomatous lesions involving the dura. No patients had extension from sites external to the CNS or clinical findings suggestive of CNS vasculitis.CONCLUSIONThe spectrum of CT and MR findings in Wegener granulomatosis includes dural thickening and enhancements cerebral infarction, and MR signal abnormalities in the brain stem and white matter. Presumed remote granulomatous lesions were the most common causes of CNS findings in this study. Complications related to non-CNS disease (eg, hypertension, endocarditis) also appear to have played a role in some patients. 相似文献
103.
Poverty, health services, and health status in rural America 总被引:5,自引:0,他引:5
Access to health services for everyone has been a major policy goal in the United States: inequitable access is assumed to lead to inequitable health status, particularly for low-income groups. A sophisticated model of the relation between poverty, health care needs, service use, and health outcomes is used to analyze cross-sectional data on 7,823 adults from 36 rural communities. Improved access and use are helpful, but evidence clearly indicates that combined health and social initiatives will be necessary to reduce inequalities in health status. 相似文献
104.
Patrick E. Barta Richard E. Powers Elizabeth H. Aylward Gary A. Chase Gordon J. Harris Peter V. Rabins Larry E. Tune Godfrey D. Pearlson 《Psychiatry Research: Neuroimaging》1997,68(2-3):65-75
Volumes of medial and lateral temporal lobe structures were assessed using magnetic resonance imaging (MRI) in 11 patients with late-life onset schizophrenia (LOS), 18 normal elderly controls and 12 patients with moderate cognitive impairment due to Alzheimer's disease (AD) who had no non-cognitive symptoms. While both patient groups has smaller volumes of several medial temporal regions (e.g. entorhinal cortex, left hippocampus), schizophrenics had significantly smaller anterior superior temporal gyri (STG) than normal controls, but AD patients did not. We have previously demonstrated anterior STG volume to be reduced in early life onset schizophrenia. 相似文献
105.
106.
Claus Jacob Alexander Y. Safronov Sonia Wilson H.Allen O. Hill Tim F. Booth 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》1997,431(1):7-10
A novel chiral redox-active ferrocene compound (FcVI) with amphiphilic properties has been synthesized. Cryogenic Transmission Electron Microscopy (cryo-TEM) has been used to estimate the shape and size of the FcVI aggregates in solution. Uni- and multi-lamellar vesicles (between 40 and 300 nm in diameter) were observed in water. Large particles (of more than 1 μm in diameter) with a hexagonal fine structure were found in 50 mM aqueous Na2SO4 solution. Sonication transformed the latter into ‘rosette’-like structures. Cyclic voltammetry has been employed to investigate the electrochemical properties of FcVI. The amphiphile adsorbed on graphite electrodes and a reversible electrochemical behaviour, characteristic of ferrocene, was observed with redox potentials between 330 and 350 mV. 相似文献
107.
Edel A. O'Toole MRCPI Patrick Deasy FRCPI † Rosemarie Watson FRCPI FACP 《Pediatric dermatology》1995,12(4):348-350
Abstract: We report a patient with cutis marmorata telangiectatica with the hitherto unreported anomaly of a double aortic arch. The presence of two major vascular anomalies in this patient may be secondary to a developmental defect of the mesoderm during embryogenesis. 相似文献
108.
R. N. Sinha A. W. Patrick L. Richardson M. Wallymahmed I. A. MacFarlane 《Postgraduate medical journal》1997,73(859):293-294
One hundred insulin-dependent diabetic patients (age < 45 years, 53 smokers) were followed for six years. The age, duration of diabetes and mean glycated haemoglobin levels, were comparable between the smokers and non-smokers. Microvascular complications (retinopathy and increased urine albumin excretion) were commoner and more severe in the smoking group at six years, particularly in heavy smokers. Of the 45 original smokers reviewed at six years, 12 (27%) had stopped, six of whom had developed microvascular complications. Only two of the ''heavy'' initial smokers, likely to be at most risk, had stopped smoking, and three original non-smokers had started smoking. 相似文献
109.
Four patients between 58 and 81 years of age undergoing investigation and endoscopic biopsy for gastric carcinoma also were subjected to direct-vision fine needle aspiration cytology of their mucosal lesions which yielded malignant cells. The relevance of this technique is discussed regarding both intrinsic and extrinsic lesions of the gastrointestinal tract. 相似文献
110.