全文获取类型
收费全文 | 1422篇 |
免费 | 112篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 76篇 |
妇产科学 | 17篇 |
基础医学 | 150篇 |
口腔科学 | 33篇 |
临床医学 | 211篇 |
内科学 | 294篇 |
皮肤病学 | 14篇 |
神经病学 | 49篇 |
特种医学 | 299篇 |
外科学 | 98篇 |
综合类 | 23篇 |
一般理论 | 1篇 |
预防医学 | 94篇 |
眼科学 | 18篇 |
药学 | 63篇 |
中国医学 | 5篇 |
肿瘤学 | 43篇 |
出版年
2023年 | 8篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 31篇 |
2017年 | 21篇 |
2016年 | 24篇 |
2015年 | 27篇 |
2014年 | 29篇 |
2013年 | 33篇 |
2012年 | 39篇 |
2011年 | 36篇 |
2010年 | 46篇 |
2009年 | 66篇 |
2008年 | 40篇 |
2007年 | 33篇 |
2006年 | 27篇 |
2005年 | 17篇 |
2004年 | 20篇 |
2003年 | 26篇 |
2002年 | 23篇 |
2001年 | 22篇 |
2000年 | 16篇 |
1999年 | 26篇 |
1998年 | 51篇 |
1997年 | 52篇 |
1996年 | 70篇 |
1995年 | 54篇 |
1994年 | 45篇 |
1993年 | 49篇 |
1992年 | 25篇 |
1991年 | 24篇 |
1990年 | 27篇 |
1989年 | 54篇 |
1988年 | 44篇 |
1987年 | 53篇 |
1986年 | 50篇 |
1985年 | 43篇 |
1984年 | 35篇 |
1983年 | 27篇 |
1982年 | 29篇 |
1981年 | 16篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 12篇 |
1977年 | 21篇 |
1976年 | 14篇 |
1975年 | 16篇 |
1971年 | 11篇 |
1970年 | 7篇 |
排序方式: 共有1541条查询结果,搜索用时 281 毫秒
101.
102.
Follicular carcinoma of the thyroid with massive angioinvasion: extension of tumor thrombus to the heart 总被引:2,自引:0,他引:2
Angioinvasion is a well documented microscopic characteristic of follicular carcinoma of the thyroid. Patients with untreated tumors may die from local invasion or metastases to the lungs, bones, or other organs. A less well recognized cause of morbidity and death from this neoplasm is angioinvasion of cervical veins with direct extension into the great veins of the chest, to the heart. Six instances of this complication have been reported previously. The most common clinical presentation of patients with neoplastic thrombus within the great veins is the superior vena cava syndrome. In each case the patient died as a result of the vascular or cardiac involvement, shortly after diagnosis. The patient reported is the first in which follicular carcinoma with extensive angioinvasion was treated. A clinical diagnosis of superior vena cava syndrome was confirmed by angiographic studies. Resection of the primary thyroid tumor and the angioinvasive extension to the heart plus 131I therapy have controlled the malignancy for at least 3 years. 相似文献
103.
104.
BACKGROUND: In this study we evaluated bone abnormalities of patients with chronic renal failure (CRF) by cortical quantitative bone ultrasound (QUS) measurements at different bone sites because these abnormalities may be of variable etiology and may start before symptoms or radiological changes are manifested. METHODS: Of fifteen patients with chronic renal failure, seven had moderate-severe disease and eight had been on chronic hemodialysis from 5 to 17 years, with renal osteodystrophy (ROD) confirmed by bone biopsies. Twelve normal subjects of similar age and gender volunteered for the control group. RESULTS: Patients and controls differed in creatinine clearance, in serum phosphate levels and in serum total alkaline phosphatase. Mean intact-PTH levels differed significantly amongst the three groups of subjects. All patients with ROD had intact-PTH higher than 200 pg/mL. The cortical ultrasound parameter, speed of sound (SOS), was slower in patients with more severe renal failure at all bone sites measured. The group with ROD had significantly lower cortical ultrasound values than the other patients and the control group at all sites. SOS values at the proximal phalanx, distal radius and midtibial sites were positively and significantly correlated. Cortical ultrasound measurements at the radial site correlated with midtibial and phalangeal sites but the correlation between midtibial and phalangeal sites did not reach significance. IPTH levels correlated negatively and significantly with cortical QUS values at all sites being the correlations higher at phalangeal and radial sites than at the midtibial region. CONCLUSIONS: The differences in cortical ultrasound observed indicate the potential clinical application of this methodology to evaluate bone abnormalities in chronic renal failure, especially in patients on chronic hemodialysis. 相似文献
105.
BACKGROUND: Through the 1990s, governments across Canada shifted health care funding allocation and organizational foci toward a community-based population health model. Major concerns of reform based on this model include ensuring equitable access to health and health care, and enhancing preventive and community-based resources for care. Reforms may act differentially relative to specific conditions and services, including those geared to chronic versus acute conditions. The present study therefore focuses on health service utilization, specifically cancer hospitalizations, in British Columbia during a decade of health system reform. METHODS: Data were drawn from the British Columbia Linked Health Data resource; income measures were derived from Statistics Canada 1996 Census public use enumeration area income files. Records with a discharge (separation) date between 1 January 1991 and 31 December 1998 were selected. All hospitalizations with ICD-9 codes 140 through 208 (except skin cancer, code 173) as principal diagnosis were included. Specific cancers analyzed include lung; colorectal; female breast; and prostate. Hospitalizations were examined in total (all separations), and as divided into first and all other hospitalizations attributed to any given individual. Annual trends in age-sex adjusted rates were analyzed by joinpoint regression; longitudinal multivariate analyses assessing association of residence and income with hospitalizations utilized generalised estimating equations. Results are evaluated in relation to cancer incidence trends, health policy reform and access to care. RESULTS: Age-sex adjusted hospitalization rates for all separations for all cancers, and lung, breast and prostate cancers, decreased significantly over the study period; colorectal cancer separations did not change significantly. Rates for first and other hospitalizations remained stationary or gradually declined over the study period. Area of residence and income were not significantly associated with first hospitalizations; effects were less consistent for all and other hospitalizations. No interactions were observed for any category of separations. CONCLUSIONS: No discontinuities were observed with respect to total hospitalizations that could be associated temporally with health policy reform; observed changes were primarily gradual. These results do not indicate whether equity was present prior to health care reform. However, findings concur with previous reports indicating no change in access to health care across income or residence consequent on health care reform. 相似文献
106.
Theriot JA Franco SM Sisson BA Metcalf SC Kennedy MA Bada HS 《Clinical pediatrics》2003,42(2):165-172
The objective of this prospective study was to determine the impact of early literacy anticipatory guidance (AG) with provision of books on language development in 3-year-olds in an early literacy program at a University-affiliated inner-city pediatric clinic. The Peabody Picture Vocabulary Test (PPVT-III) and the Expressive One Word Picture Vocabulary Test (EOWPVT-R) were administered to 33-39-month-old children exposed to an early literacy program, which included AG and provision of an age-appropriate book at each well-child visit starting at 2 months old. Children with developmental delays were excluded. Parental surveys on literacy and demographic data were obtained. Univariate and multivariate analyses were performed. Sixty-four children were evaluated; 88% African American, 89% Medicaid recipients. Fifty-eight percent of families reported family-centered literacy orientation. The PPVT-III scores directly correlated with the number of AG visits with book given x number of books purchased (r2 = 0.025, p = 0.0006). Higher scores in EOWPVT-R were predicted by race and the number of visits with books given x number of books purchased (r2 = 0.182, p = 0.0009). All families reported reading together, half reporting positive family-centered literacy. Given the same number of books purchased for each child, the outcome scores were higher the greater the number of clinic visits wherein AG included early literacy and provision of books. 相似文献
107.
108.
Recent publications have reported impressive success with laryngeal reinnervation utilizing a nerve-muscle pedicle. This innovative surgical procedure is claimed to be useful for unilateral and bilateral vocal cord paralysis. Although the surgical results reported by Tucker have been good, they have lacked corroboration from other centers. We have performed six laryngeal reinnervation procedures at Northwestern University Medical School. Four patients presented with bilateral vocal cord paralysis and two patients with unilateral paralysis. All six operations were successful in restoring vocal cord function. The technique, problems, and results are discussed. Our experience supports the initial reports of success with this new operation. 相似文献
109.
Tumors of the major salivary glands. 总被引:2,自引:0,他引:2
Tumors of the major salivary glands are reviewed according to classification, location, surgical procedure and end results. Our data of the incidence of benign and malignant tumors show that the most commonly involved area is the parotid gland and the most frequent is of the mixed variety. In the parotid region 80 percent are benign and 20 percent are malignant; whereas, in the submandibular gland, the malignant and benign tumors are equally distributed. The need for an extensive surgical attack and inclusion of contiguous structure is dictated by the nature of the malignant disease. The role of postoperative irradiation is discussed as is the indication for neck dissection. Management of the facial nerve, relative to malignant tumors of the parotid gland, is considered in detail. 相似文献
110.
Casanueva FF Molitch ME Schlechte JA Abs R Bonert V Bronstein MD Brue T Cappabianca P Colao A Fahlbusch R Fideleff H Hadani M Kelly P Kleinberg D Laws ED Marek J Scanlon M Sobrinho LG Wass JAH Giustina A 吴哲褒 张亚卓 《中华神经外科杂志》2008,24(8)
3.男性:高催乳素血症通常导致阳痿、不孕和性功能低下.男性患者通常为大腺瘤,有神经系统症状.其原因可能是对症状认识的延误或者肿瘤生物学行为的差异. 相似文献