全文获取类型
收费全文 | 11336篇 |
免费 | 837篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 85篇 |
儿科学 | 310篇 |
妇产科学 | 319篇 |
基础医学 | 1559篇 |
口腔科学 | 250篇 |
临床医学 | 1384篇 |
内科学 | 2206篇 |
皮肤病学 | 290篇 |
神经病学 | 1314篇 |
特种医学 | 204篇 |
外科学 | 1004篇 |
综合类 | 68篇 |
一般理论 | 16篇 |
预防医学 | 1363篇 |
眼科学 | 200篇 |
药学 | 771篇 |
中国医学 | 32篇 |
肿瘤学 | 836篇 |
出版年
2023年 | 137篇 |
2022年 | 234篇 |
2021年 | 465篇 |
2020年 | 272篇 |
2019年 | 373篇 |
2018年 | 389篇 |
2017年 | 280篇 |
2016年 | 330篇 |
2015年 | 330篇 |
2014年 | 408篇 |
2013年 | 606篇 |
2012年 | 867篇 |
2011年 | 874篇 |
2010年 | 514篇 |
2009年 | 401篇 |
2008年 | 675篇 |
2007年 | 672篇 |
2006年 | 629篇 |
2005年 | 587篇 |
2004年 | 496篇 |
2003年 | 486篇 |
2002年 | 427篇 |
2001年 | 88篇 |
2000年 | 65篇 |
1999年 | 77篇 |
1998年 | 79篇 |
1997年 | 76篇 |
1996年 | 70篇 |
1995年 | 60篇 |
1994年 | 56篇 |
1993年 | 59篇 |
1992年 | 59篇 |
1991年 | 64篇 |
1990年 | 59篇 |
1989年 | 75篇 |
1988年 | 57篇 |
1987年 | 54篇 |
1986年 | 37篇 |
1985年 | 43篇 |
1984年 | 55篇 |
1983年 | 49篇 |
1982年 | 37篇 |
1981年 | 44篇 |
1980年 | 48篇 |
1979年 | 26篇 |
1978年 | 28篇 |
1977年 | 29篇 |
1975年 | 25篇 |
1974年 | 24篇 |
1973年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 29 毫秒
31.
ABSTRACT: This paper reports on the effectiveness of a teacher development project in promoting implementation of a comprehensive school health education curriculum among inner city elementary school teachers. The longitudinal evaluation design provides empirical data on the efficacy of a strategy to reduce teachers' concerns and promote use of the curriculum at the classroom level. Data were collected at various points throughout the project period from 156 school staff from five schools. Results from analyses of repeated measures of teachers' feelings of preparedness to teach specific health topics, and the observed relationship between both high and improved feelings of preparation and reported health teaching suggest that teacher development efforts including training and ongoing reinforcement to increase teachers' feelings of preparedness can have significant classroom effects. 相似文献
32.
33.
34.
C.-J. Wallin 《Acta anaesthesiologica Scandinavica》1998,42(3):383-383
Background: Pulmonary oedema is life threatening. A method is needed for reliable measurement of lung water in man in order to clarify aetiology, pathophysiology, prognosis, and to evaluate treatments against pulmonary oedema. Methods: The double-indicator dilution method with bolus injection and optical detection of heavy water and indocyanine green in arterial blood for the measurement of cardiac output, central blood volume and lung water was applied in two human and two experimental studies. In parallel, the thermo-dye technique was tested in one of the experimental studies. The results from these four studies, together with results presented in the literature, were analysed according to the criteria set forth by The National Institute of Health, USA 1985, for the measurement of lung water in man, that is versatility, reproducibility, sensitivity, and accuracy. Results: for the heavy water-indocyanine green method: Versatility: No adverse reaction was recorded in the two human studies. A central venous line and a peripheral arterial line, or access to an arterio-venous fistula, were needed for bolus injection and concentration analysis. In-line optical detection of heavy water and indocyanine green did not expose the subjects to radio-labelled isotopes and the blood loss was low compared to timed blood volume collection. Reproducibility: The coefficient of variation was below 10% for cardiac output and central blood volume, and 10–17% for lung water. Sensitivity: Changes in lung water that were below the level of gas exchange disturbance could be detected in a group of subjects. Accuracy: Cardiac output, mean transit time and lung water for heavy water were linearly related to independent reference measures. Evidence for barrier limitations for heavy water in the clinical setting were weak. The indicator dilution method is unreliable for shock states and pulmonary embolism. Results: for the thermo-dye method: Versatility: The method did not expose the subjects to radio-labelled isotopes and there was no blood loss, but the method requires a central venous line and a thermistor-equipped fibre-optic catheter placed in the aorta. Reproducibility: The coefficient of variation was approximately 10% for cardiac output, central blood volume and lung water. Sensitivity: In healthy lungs, small differences in lung water can be detected. In pulmonary oedema, the large increase in deviation cripples the sensitivity of the method. Accuracy: Recovery of the thermal indicator and the error in its mean transit time were dependent on the distribution volume for the indicator cold. This undermines reliable calculation of cardiac output and lung water. Conclusions: The method using optical detection of heavy water and indocyanine green in blood for the measurement of cardiac output, central blood volume and lung water in humans is an improvement with regard to radio-labelled methods, with the same reproducibility. The method allows for detection of small changes in lung water under the range where gas-exchange disturbance occurs. The method provides values close to gravimetric lung water values in both healthy and grossly oedematous lungs, independent of cardiac output and distribution volume, with the exception of shock states and severe vascular obstruction. 相似文献
35.
36.
37.
Brigitte Schiller Chun He David J. Salant Alice Lim Jessy J. Alexander Richard J. Quigg 《The Journal of experimental medicine》1998,188(7):1353-1358
Crry (complement receptor 1–related protein/gene y) is a key cellular complement regulator in rodents. It is also present in Fx1A, the renal tubular preparation used to immunize rats to induce active Heymann nephritis (HN), a model of membranous nephropathy. We hypothesized that rats immunized with anti-Fx1A develop autoantibodies (auto-Abs) to Crry as well as to the megalin-containing HN antigenic complex, and that anti-Crry Abs promote the development of injury in HN by neutralizing the complement regulatory activity of Crry. Rats immunized with Fx1A lacking Crry remained free of proteinuria and glomerular deposits of C3 during a 10-wk follow-up despite typical granular immunoglobulin (Ig)G deposits in glomeruli. Anti-Fx1A auto-Abs were present in their sera at levels that were not different from sera pooled from proteinuric rats with HN induced with nephritogenic Fx1A. Passive administration of sheep anti-Crry Abs to rats immunized with Crry-deficient Fx1A led to proteinuria and glomerular C3 deposition, which were not seen in such rats injected with preimmune IgG, nor in rats with collagen-induced arthritis injected with anti-Crry IgG. To directly examine the role of Crry in HN, rats were immunized with Crry-deficient Fx1A reconstituted with rCrry. This led to typical HN, with 8 out of 15 rats developing proteinuria within 14 wk. Moreover, the extent of glomerular C3 deposition correlated with proteinuria, and anti-Crry Abs were present in glomerular eluates. Thus, Crry is a key nephritogenic immunogen in Fx1A. Formation of neutralizing auto-Abs to Crry impairs its function, leading to unrestricted complement activation by Abs reactive with the HN antigenic complex on the epithelial cell surface. 相似文献
38.
This study was performed to test the existing notion that an increased muscle sympathetic nerve discharge is part of the underlying mechanism for the chronic pain syndrome of primary fibromyalgia. Muscle sympathetic nerve activity was recorded in the peroneal nerve in eight patients with primary fibromyalgia and eight age-matched controls. No difference in baseline sympathetic activity was observed between patients and controls. Furthermore, patients did not show exaggerated sympathetic nerve responses to static handgrip or jaw muscle contractions, postcontraction ischemia or mental stress. Thus the results do not indicate muscle sympathetic nerve overactivity in primary fibromyalgic patients. 相似文献
39.
Hexane and methanol extracts of heartwood, bark/sapwood and leaves of twelve taxa of Juniperus from the United States were assayed for antifungal and antibacterial activities. The hexane extract of the heartwood of several junipers appeared comparable in antibacterial activity to streptomycin. Antibacterial activity of the hexane extracts from the bark/sapwood of J. monosperma and J. californica were comparable to streptomycin. No appreciable antibacterial activities were found in the leaf extracts from any species examined. No antifungal activities comparable to amphotericin B were found in either hexane or methanol extracts of the heartwood nor from the bark/sapwood. Antifungal activity against Cryptococcus neoformans comparable to amphotericin B was found in the hexane extract of the leaves of J. occidentalis var. australis. The methanol extracts from the leaves of J. osteosperma and J. californica had antifungal activities comparable to amphotericin B against Trichophyton mentagrophytes. 相似文献
40.
John E. Geltosky Richard S. Smith Alice Whalley Gary Rhodes 《Journal of clinical laboratory analysis》1987,1(2):153-162
A simple enzyme immunoassay has been developed based on measuring antibodies to synthetic peptides corresponding to sequences in the Epstein-Barr nuclear antigen (EBNA). This assay, which is reproducible, quantitative, and simple to perform and interpret, can be an effective tool to aid in the diagnosis of infectious mononucleosis and nasopharyngeal carcinoma. 相似文献