全文获取类型
收费全文 | 14554篇 |
免费 | 932篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 415篇 |
妇产科学 | 396篇 |
基础医学 | 1716篇 |
口腔科学 | 178篇 |
临床医学 | 2247篇 |
内科学 | 3001篇 |
皮肤病学 | 178篇 |
神经病学 | 1437篇 |
特种医学 | 241篇 |
外科学 | 1297篇 |
综合类 | 389篇 |
一般理论 | 18篇 |
预防医学 | 2031篇 |
眼科学 | 262篇 |
药学 | 636篇 |
中国医学 | 15篇 |
肿瘤学 | 1003篇 |
出版年
2023年 | 78篇 |
2022年 | 90篇 |
2021年 | 261篇 |
2020年 | 152篇 |
2019年 | 239篇 |
2018年 | 284篇 |
2017年 | 217篇 |
2016年 | 230篇 |
2015年 | 289篇 |
2014年 | 430篇 |
2013年 | 694篇 |
2012年 | 976篇 |
2011年 | 1123篇 |
2010年 | 593篇 |
2009年 | 522篇 |
2008年 | 999篇 |
2007年 | 1053篇 |
2006年 | 1001篇 |
2005年 | 1000篇 |
2004年 | 976篇 |
2003年 | 887篇 |
2002年 | 837篇 |
2001年 | 123篇 |
2000年 | 112篇 |
1999年 | 143篇 |
1998年 | 209篇 |
1997年 | 150篇 |
1996年 | 131篇 |
1995年 | 122篇 |
1994年 | 105篇 |
1993年 | 94篇 |
1992年 | 74篇 |
1991年 | 65篇 |
1990年 | 68篇 |
1989年 | 72篇 |
1988年 | 60篇 |
1987年 | 48篇 |
1986年 | 53篇 |
1985年 | 54篇 |
1984年 | 71篇 |
1983年 | 81篇 |
1982年 | 73篇 |
1981年 | 77篇 |
1980年 | 63篇 |
1979年 | 48篇 |
1978年 | 52篇 |
1977年 | 43篇 |
1976年 | 37篇 |
1975年 | 31篇 |
1974年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
Emiri Tejima Bing-Qiao Zhao Kiyoshi Tsuji Anna Rosell Klaus van Leyen R Gilberto Gonzalez Joan Montaner Xiaoying Wang Eng H Lo 《Journal of cerebral blood flow and metabolism》2007,27(3):460-468
We tested the hypothesis that astrocytic matrix metalloproteinase-9 (MMP-9) mediates hemorrhagic brain edema. In a clinical case of hemorrhagic stroke, MMP-9 co-localized with astrocytes and neurons in peri-hematoma areas. In a mouse model where blood was injected into striatum, MMP-9 was colocalized with astrocytes surrounding the hemorrhagic lesion. Because MMP-9 is present in blood as well as brain, we compared four groups of wild type (WT) and MMP-9 knockout (KO) mice: WT blood injected into WT brain, KO blood into KO brain, WT blood into KO brain, and KO blood into WT brain. Gel zymography showed that MMP-9 was elevated in WT hemorrhagic brain tissue but absent from KO hemorrhagic brain tissue. Edematous water content was elevated when WT blood was injected into WT brain. However, edema was ameliorated when MMP-9 was absent in either blood or brain or both. To further assess the mechanisms involved in astrocytic induction of MMP-9, we next examined primary mouse astrocyte cultures. Exposure to hemoglobin rapidly upregulated MMP-9 in conditioned media within 1 to 24 h. Hemoglobin-induced MMP-9 was reduced by the free radical scavenger U83836E. Taken together, these data suggest that although there are large amounts of MMP-9 in blood, hemoglobin-induced oxidative stress can trigger MMP-9 in astrocytes and these parenchymal sources of matrix degradation may also be an important factor in the pathogenesis of hemorrhagic brain edema. 相似文献
44.
45.
Eugénie C.H. van den Ham Jeroen P. Kooman Annemie M.W.J. Schols Fred H.M. Nieman Joan D. Does Frits M.E. Franssen Marco A. Akkermans Paul P. Janssen Johannes P. van Hooff 《American journal of transplantation》2005,5(8):1957-1965
Exercise intolerance is common in hemodialysis (HD) and renal transplant (RTx) patients. Aim of the study was to assess to what extent exercise capacity and skeletal muscle strength of RTx patients differ from HD patients and healthy controls and to elucidate potential determinants of exercise capacity in RTx patients. Exercise capacity, muscle strength, lean body mass (LBM) and physical activity level (PAL) were measured by cycle-ergometry, isokinetic dynamometry, DEXA and Baecke Questionnaire, respectively, in 35 RTx, 16 HD and 21 controls. VO2peak and muscle strength of the RTx patients were significantly lower compared to controls (p<0.01), but not different compared to HD patients. In RTx patients, strength (p<0.001), PAL (p=0.001) and age (p=0.045) were significant predictors of VO2peak. Muscle strength was related to LBM (p=0.001) and age (p=0.001), whereas gender (p<0.001) and renal function (p=0.01) turned out to be significant predictors of LBM. No effects of corticosteroids were observed. Exercise capacity and muscle strength seem equally reduced in RTx and HD patients compared to controls. In RTx patients, muscle strength and PAL are highly related to exercise capacity. Renal function appears to be a significant predictor of LBM, and through the LBM, of muscle strength and exercise capacity. 相似文献
46.
Avian influenza (AI) and Newcastle disease (ND) viruses are heat labile viruses, but exact parameters for heat inactivation at egg pasteurization temperatures have not been established. In this study we artificially infected four egg products with two AI (one low [LP] and one high pathogenicity [HP]) and three ND (two low and one highly virulent) viruses, and determined inactivation curves at 55, 57, 59, 61 and 63 degrees C. Based on D(t) values, the time to inactivation of the viruses was dependent on virus strain and egg product, and was directly related to virus titre, but inversely related to temperature. For all temperatures, the five viruses had the most rapid and complete inactivation in 10% salt yolk, while the most resistant to inactivation was HPAI virus in dried egg white. This study demonstrated that the LPAI and all ND viruses were inactivated in all egg products when treated using industry standard pasteurization protocols. By contrast, the HPAI virus was inactivated in liquid egg products but not in dried egg whites when using the low-temperature industry pasteurization protocol. 相似文献
47.
Personal Digital Assistants (PDAs) are a readily accessible source of information to aid in the delivery of patient care. A pilot group of five Family Nurse Practitioner students used PDAs to organize data and access information relevant to patient care. Utilization of the PDAs in the clinical setting provided practice guidelines, textbook information and protocols that were readily accessible. The PDA made it possible for students to utilize preexisting knowledge with additional learning resources. The PDAs were purchased with funds provided from a United States Department of Health and Human Services, Health Resources and Services Administration (HRSA) grant. 相似文献
48.
Marc Tey Joan C. Monllau Josep M. Centenera Xavier Pelfort 《Knee surgery, sports traumatology, arthroscopy》2007,15(10):1235-1239
The purpose of this work was to describe the posterior ankle impingement syndrome related to the posterolateral tubercle of
the talus bone and to present a retrospective analysis of our results after arthroscopic plasty of the tubercle in 15 ankles
with a mean 3-year follow-up. Fifteen cases of posterior ankle impingement (PAI) underwent arthroscopic excision of an impinging
bone spur. All the patients (13) were retrospectively evaluated at an average of 36 months after index surgery. There were
seven women (bilateral in two of them) and six men. Ten were involved in different kinds of sport and three were professional
ballet dancers. Preoperative symptoms included pain localized in the posterior ankle, limitation of motion, weakness and swelling.
All patients had failed a course of conservative therapies. Surgery was performed through posterolateral and posteromedial
portals as described by van Dijk. After soft tissue debridement, partial resection of the posterolateral process was performed
until there was complete plantar flexion without bone impingement. Postoperatively, all patients followed the same rehabilitation
protocol. Improvement in their impingement symptoms was recorded in all of them according to AOFAS score. One of them (7%)
still had occasional discomfort. The results suggest that arthroscopic bone decompression of the posterolateral tubercle in
cases of PAI resistant to non-surgical therapies is an effective treatment. 相似文献
49.
JoAnn G. Congdon Ph.D. R.N. Joan K. Magilvy Ph.D. R.N. FAAN 《Public health nursing (Boston, Mass.)》1995,12(1):18-24
Abstract Rural community and public health nursing are characterized by an impressive commitment of nurses to their communities and a connectedness of people to one another. Home care as an integral part of long-term and acute care for the older adult population has emerged as a vital practice area in community health nursing. The purpose of this ethnographic field study was to describe rural home care for frail older adults from the perspective of those providing and receiving care. More than 250 interviews were conducted with home care providers, recipients and their families, and other community members. The setting included eight culturally and geographically diverse counties in rural Colorado. One major theme is presented: the perceived change in the spirit of rural community nursing due to the overwhelming documentation required for home care reimbursement. Oppressive paperwork requirements impeded practice and resulted in fewer home visits per day, low job satisfaction, increased nursing staff turnover, decreased quality of care, and changed the spirit of community nursing from an emphasis on caring and community service to a focus on reimbursement. The study results have timely implications for health policy formulation as the United States undergoes major health care reform. 相似文献
50.
This article examines how the death of a parent, particularly the father, can create an immediate crisis for the surviving spouse and children. The problems of being a widow or being a child or teenager who has lost his or her father to death are explored in detail. Interventions are suggested and explored in terms of the literature, empirical work, and anecdotal material. The authors raise many questions about how death impacts family members and whether or not interventions are needed. 相似文献