全文获取类型
收费全文 | 52622篇 |
免费 | 3889篇 |
国内免费 | 645篇 |
专业分类
耳鼻咽喉 | 453篇 |
儿科学 | 1354篇 |
妇产科学 | 1101篇 |
基础医学 | 6664篇 |
口腔科学 | 959篇 |
临床医学 | 5398篇 |
内科学 | 11160篇 |
皮肤病学 | 868篇 |
神经病学 | 4918篇 |
特种医学 | 1773篇 |
外国民族医学 | 4篇 |
外科学 | 7122篇 |
综合类 | 1670篇 |
一般理论 | 32篇 |
预防医学 | 4046篇 |
眼科学 | 1179篇 |
药学 | 4008篇 |
5篇 | |
中国医学 | 390篇 |
肿瘤学 | 4052篇 |
出版年
2023年 | 403篇 |
2022年 | 758篇 |
2021年 | 1297篇 |
2020年 | 794篇 |
2019年 | 1128篇 |
2018年 | 1226篇 |
2017年 | 992篇 |
2016年 | 1059篇 |
2015年 | 1352篇 |
2014年 | 1785篇 |
2013年 | 2309篇 |
2012年 | 3532篇 |
2011年 | 3887篇 |
2010年 | 2205篇 |
2009年 | 1974篇 |
2008年 | 3137篇 |
2007年 | 3419篇 |
2006年 | 3253篇 |
2005年 | 3300篇 |
2004年 | 2970篇 |
2003年 | 2762篇 |
2002年 | 2518篇 |
2001年 | 795篇 |
2000年 | 653篇 |
1999年 | 781篇 |
1998年 | 599篇 |
1997年 | 487篇 |
1996年 | 511篇 |
1995年 | 421篇 |
1994年 | 349篇 |
1993年 | 356篇 |
1992年 | 421篇 |
1991年 | 400篇 |
1990年 | 336篇 |
1989年 | 292篇 |
1988年 | 298篇 |
1987年 | 258篇 |
1986年 | 222篇 |
1985年 | 280篇 |
1984年 | 323篇 |
1983年 | 275篇 |
1982年 | 298篇 |
1981年 | 303篇 |
1980年 | 287篇 |
1979年 | 176篇 |
1978年 | 181篇 |
1977年 | 160篇 |
1976年 | 136篇 |
1974年 | 135篇 |
1973年 | 99篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Single photon emission computed tomography using 99mTc-HM-PAO in the routine evaluation of Alzheimer's disease 总被引:1,自引:0,他引:1
T A Hurwitz W Ammann D Chu C Clark J Holden R Brownstone 《The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques》1991,18(1):59-62
Regional cerebral blood flow was studied in 7 patients with clinically suspected Alzheimer's disease and 10 normal controls by single photon computed emission tomography (SPECT) using HM-PAO. All patients with Alzheimer's disease and no controls had parietal lobe hypoperfusion which was usually bilateral. In patients with more severe dementia hypoperfusion extended into the frontal lobes. Parietal lobe hypoperfusion corresponds to parietal lobe degeneration which is the one of the first neocortical regions to show the typical degenerative changes of Alzheimer's disease. SPECT with HM-PAO is a non-invasive investigation available in most nuclear medicine departments and complements existing tests in the routine evaluation of patients presenting with dementia. 相似文献
52.
W W Huurman F S Jacobsen J C Anderson W K Chu 《The Journal of bone and joint surgery. American volume》1987,69(5):699-705
A simple, rapid, and accurate method for measuring limb-length discrepancies with computerized axial tomographic equipment is described. With this method less irradiation is delivered and some of the errors of computation are eliminated, compared with conventional methods. The costs of the technique are comparable with those of scanograms. The method is particularly applicable in the patient who has contracture of a joint. 相似文献
53.
54.
55.
Background : The present paper addressed the issue of whether pretreatment with intravenous (IV) chemotherapy affects response rate or survival in patients receiving hepatic artery chemotherapy (HAC). Methods : Case note reviews of 164 patients treated in a teaching hospital from June 1990 to July 1996 were carried out. Results : The response rate and carcino-embryonic antigen (CEA) fall in the two groups was almost identical. There was a nonsignificant survival advantage in the non-pretreatment group. Conclusions : Previous administration of IV chemotherapy did not affect the CEA response of patients receiving HAC. 相似文献
56.
Philip W. H. Peng David T. Wong David Bevan Michael Gardam 《Journal canadien d'anesthésie》2003,50(10):989-997
PURPOSE: To describe the outbreak of severe acute respiratory syndrome (SARS) in Toronto, its impact on anesthesia practice and the infection control guidelines adopted to manage patients in the operating room (OR) and to provide emergency intubation outside the OR. Clinical features: The SARS outbreak in Toronto was the result of a single index patient. The causative virus, SARS-CoV, is moderately contagious, and is spread by droplets and contact. The virus gains access to host through the mucosa of the respiratory tract and the eyes. It can affect both healthy and compromised patients. The use of several precautionary measures such as goggles, gloves, gowns and facemasks and the application of various infection control strategies designed to minimize the spread of the virus are discussed. CONCLUSION: In containing the spread of SARS, vigilance and strict infection control are important. This results in the rediscovery of standards of infection control measures in daily anesthesia practice. 相似文献
57.
58.
Radionuclide targeting and dosimetry at the microscopic level: the role of microautoradiography 总被引:1,自引:0,他引:1
Matthew R. B. Puncher Philip J. Blower 《European journal of nuclear medicine and molecular imaging》1994,21(12):1347-1365
The understanding of localisation mechanisms and microdosimetry of diagnostic and therapeutic radiopharmaceuticals depends
on knowledge of their biodistribution at the microscopic level (cellular and subcellular) in the target tissues. Various methods
have been advanced for obtaining information about this microdistribution: subcellular fractionation, secondary ion mass spectrometry
imaging, microprobe elemental analysis in the electron microscope, and microautoradiography. This review compares these approaches,
and discusses in detail the methodology of microautoradiography (the most generally useful approach) with imaging and therapy
radionuclides. Literature examples of applications of microautoradiography in nuclear medicine are reviewed, and the future
potential contribution of the techniques is assessed. 相似文献
59.
60.
H. W. Chu S. Balzar J. Y. Westcott J. B. Trudeau Y. Sun D. J. Conrad S. E. Wenzel 《Clinical and experimental allergy》2002,32(11):1558-1565
BACKGROUND: Although 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), a product of 15-lipoxygenase (15-LO), may be involved in mild to moderate asthma, little is known about its potential roles in severe asthma. OBJECTIVES: This study was performed to evaluate 15(S)-HETE levels in bronchoalveolar lavage fluid (BALF) from severe asthmatics with and without airway eosinophils and from the control groups. In addition, 15-LO protein expression was examined in endobronchial biopsy, while its expression and activation were evaluated in BAL cells. RESULTS: While 15(S)-HETE levels in BALF were significantly higher in all severe asthmatics than normal subjects, severe asthmatics with airway eosinophils had the highest levels compared with mild, moderate asthmatics and normal subjects. 15(S)-HETE levels were associated with tissue eosinophil numbers, sub-basement membrane thickness and BALF tissue inhibitor of metalloproteinase-1 levels, and were accompanied by increased 15-LO expression in bronchial epithelium. In addition, activation of 15-LO was suggested by the increased proportion of 15-LO in the cytoplasmic membrane of alveolar macrophages from severe asthmatics. CONCLUSION: The data suggest that severe asthmatics with persistent airway eosinophils manifest high levels of 15(S)-HETE in BALF, which may be associated with airway fibrosis. It is likely that 15-LO expression and activation by airway cells explain the increased 15(S)-HETE levels. 相似文献