全文获取类型
收费全文 | 222293篇 |
免费 | 4776篇 |
国内免费 | 119篇 |
专业分类
耳鼻咽喉 | 1503篇 |
儿科学 | 8671篇 |
妇产科学 | 4433篇 |
基础医学 | 22791篇 |
口腔科学 | 2020篇 |
临床医学 | 18896篇 |
内科学 | 39527篇 |
皮肤病学 | 1422篇 |
神经病学 | 21023篇 |
特种医学 | 9907篇 |
外国民族医学 | 38篇 |
外科学 | 33260篇 |
综合类 | 2818篇 |
一般理论 | 101篇 |
预防医学 | 24878篇 |
眼科学 | 3378篇 |
药学 | 12017篇 |
中国医学 | 708篇 |
肿瘤学 | 19797篇 |
出版年
2023年 | 457篇 |
2022年 | 624篇 |
2021年 | 1549篇 |
2020年 | 927篇 |
2019年 | 1468篇 |
2018年 | 23361篇 |
2017年 | 18376篇 |
2016年 | 20613篇 |
2015年 | 2248篇 |
2014年 | 2679篇 |
2013年 | 3518篇 |
2012年 | 10802篇 |
2011年 | 24805篇 |
2010年 | 20749篇 |
2009年 | 13268篇 |
2008年 | 22701篇 |
2007年 | 24850篇 |
2006年 | 3560篇 |
2005年 | 5123篇 |
2004年 | 6032篇 |
2003年 | 6710篇 |
2002年 | 4729篇 |
2001年 | 575篇 |
2000年 | 611篇 |
1999年 | 482篇 |
1998年 | 655篇 |
1997年 | 546篇 |
1996年 | 385篇 |
1995年 | 405篇 |
1994年 | 361篇 |
1993年 | 286篇 |
1992年 | 183篇 |
1991年 | 242篇 |
1990年 | 254篇 |
1989年 | 196篇 |
1988年 | 175篇 |
1987年 | 129篇 |
1986年 | 131篇 |
1985年 | 144篇 |
1984年 | 144篇 |
1983年 | 135篇 |
1982年 | 150篇 |
1981年 | 162篇 |
1980年 | 153篇 |
1979年 | 78篇 |
1978年 | 70篇 |
1977年 | 75篇 |
1976年 | 74篇 |
1974年 | 83篇 |
1938年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 656 毫秒
71.
Irwin L. Flink 《Brain structure & function》2002,205(3):235-244
72.
73.
74.
Loss of basal forebrain P75(NTR) immunoreactivity in subjects with mild cognitive impairment and Alzheimer's disease. 总被引:13,自引:0,他引:13
Elliott J Mufson Shuang Y Ma John Dills Elizabeth J Cochran Sue Leurgans Joanne Wuu David A Bennett Syed Jaffar Michelle L Gilmor Alan I Levey Jeffrey H Kordower 《The Journal of comparative neurology》2002,443(2):136-153
The long-held belief that degeneration of the cholinergic basal forebrain was central to Alzheimer's disease (AD) pathogenesis and occurred early in the disease process has been questioned recently. In this regard, changes in some cholinergic basal forebrain (CBF) markers (e.g. the high affinity trkA receptor) but not others (e.g., cortical choline acetyltransferase [ChAT] activity, the number of ChAT and vesicular acetylcholine transporter-immunoreactive neurons) suggest specific phenotypic changes, but not frank neuronal degeneration, early in the disease process. The present study examined the expression of the low affinity p75 neurotrophin receptor (p75(NTR)), an excellent marker of CBF neurons, in postmortem tissue derived from clinically well-characterized individuals who have been classified as having no cognitive impairment (NCI), mild cognitive impairment (MCI), and mild AD. Relative to NCI individuals, a significant and similar reduction in the number of nucleus basalis p75(NTR)-immunoreactive neurons was seen in individuals with MCI (38%) and mild AD (43%). The number of p75(NTR)-immunoreactive nucleus basalis neurons was significantly correlated with performance on the Mini-Mental State Exam, a Global Cognitive Test score, as well as some individual tests of working memory and attention. These data, together with previous reports, support the concept that phenotypic changes, but not frank neuronal degeneration, occur early in cognitive decline. Although there was no difference in p75(NTR) CBF cell reduction between MCI and AD, it remains to be determined whether these findings lend support to the hypothesis that MCI is a prodromal stage of AD. 相似文献
75.
76.
Bone mineral density testing in healthy postmenopausal women. The role of clinical risk factor assessment in determining fracture risk. 总被引:5,自引:0,他引:5
William D Leslie Colleen Metge Elizabeth A Salamon C Kin Yuen 《Journal of clinical densitometry》2002,5(2):117-130
The ease of measurement and the quantitative nature of bone mineral densitometry (BMD) is clinically appealing. Despite BMD's proven capability to stratify fracture risk, data indicate that clinical risk factors provide complementary information on fracture susceptibility that is independent of BMD. Methods to quantify fracture risk using both clinical and BMD variables would have great appeal for clinical decision-making. We describe a procedure for quantifying hip fracture risk (5-yr and remaining lifetime) based on (1) the individual's age alone (base model, assuming average clinical risk factors and bone density), (2) incorporation of multiple patient-specific clinical risk factor data in the base model, and (3) incorporation of both patient-specific clinical risk factor data and BMD results. 相似文献
77.
78.
79.
Scott A Fields Elizabeth Morrison Ernie Yoder Kevin Krane Thomas Agresta Rich Esham Frederick McCurdy Jonathan Rosen James Shumway 《Academic medicine》2002,77(6):543-546
PURPOSE: Chart notes are used to support billing codes under the evaluation and management guidelines of the Health Care Financing Administration (HCFA), in addition to serving as a record of the visit. To better understand the effect of the HCFA documentation guidelines, the authors collected data on how the guidelines affect participation by university- and community-based faculty in clinical education programs. METHOD: In 2000, the authors sent six copies of their questionnaire to the associate deans of the 125 U.S. medical schools and requested they distribute them to all core clerkship directors. The questionnaire consisted of multiple-choice and short-answer questions regarding documentation of medical visits, participation of community-based faculty, understanding of HCFA documentation guidelines, and effects on education programs. RESULTS: The response rate was about 50%. Most of the 379 clerkship directors who responded (77%) stated they were aware the HCFA documentation guidelines include specifications regarding the role medical students can play and documentation of medical visits, and 64% indicated they were concerned the guidelines would affect their educational programs. Concerns included the loss of student independence and active participation in the patient care environment (37), time constraints and the changing balance between education and service (16), loss of faculty and decreased morale (11), and decreased quality of care for patients (7). CONCLUSION: Leaders of medical education must work to modify these guidelines to protect the quality of patients' care, while maximizing students' educational opportunity and participation. 相似文献
80.
Paul Hochstein Ulrich Glatzel Thomas Schmickal Andreas Wentzensen 《Trauma und Berufskrankheit》2002,4(2):s110-s114
The treatment of deep cartilage defects in load-bearing joints is a problem that still has no satisfactory solution. Full-thickness defects of the articular cartilage rarely heal spontaneously, usually leaving damage that can lead to early arthrosis. Techniques currently available for the treatment of chondral defects include abrasion, drilling, micro-fracturing, transplantation of tissue autografts and allografts, and cell transplantation. Osteochondral autograft transplantation is currently the only surgical cartilage repair technique known to lead to the formation of genuine hyaline articular cartilage and its retention at least in the medium term. The Draenert method, in which a water-cooled diamond bone-cutting system is used, is an effective procedure for resurfacing the joints affected by localised cartilaginous defects, even when there is also severe bone loss. Donor-side morbidity can be kept to a minimum by filling the defect caused by harvesting with a press-fit cylinder of cancellous bone covered with periosteum for protection. 相似文献