全文获取类型
收费全文 | 1715篇 |
免费 | 109篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 30篇 |
妇产科学 | 29篇 |
基础医学 | 243篇 |
口腔科学 | 15篇 |
临床医学 | 175篇 |
内科学 | 284篇 |
皮肤病学 | 54篇 |
神经病学 | 137篇 |
特种医学 | 71篇 |
外国民族医学 | 2篇 |
外科学 | 356篇 |
综合类 | 12篇 |
预防医学 | 157篇 |
眼科学 | 11篇 |
药学 | 116篇 |
中国医学 | 1篇 |
肿瘤学 | 131篇 |
出版年
2021年 | 33篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 34篇 |
2017年 | 16篇 |
2016年 | 31篇 |
2015年 | 19篇 |
2014年 | 43篇 |
2013年 | 83篇 |
2012年 | 104篇 |
2011年 | 104篇 |
2010年 | 48篇 |
2009年 | 51篇 |
2008年 | 82篇 |
2007年 | 74篇 |
2006年 | 95篇 |
2005年 | 84篇 |
2004年 | 103篇 |
2003年 | 67篇 |
2002年 | 95篇 |
2001年 | 61篇 |
2000年 | 58篇 |
1999年 | 51篇 |
1998年 | 31篇 |
1997年 | 14篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 22篇 |
1991年 | 25篇 |
1990年 | 21篇 |
1989年 | 18篇 |
1988年 | 14篇 |
1987年 | 27篇 |
1986年 | 29篇 |
1985年 | 19篇 |
1984年 | 17篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1979年 | 10篇 |
1978年 | 14篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 21篇 |
1974年 | 14篇 |
1973年 | 18篇 |
1972年 | 7篇 |
1971年 | 10篇 |
排序方式: 共有1830条查询结果,搜索用时 15 毫秒
1.
Marcel Toussaint Raymond J. Gilles Noura Azzabou Benjamin Marty Alexandre Vignaud Andreas Greiser Pierre G. Carlier 《Medicine》2015,94(43)
Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis. 相似文献
2.
A T Farrell I Papadouli A Hori M Harczy B Harrison W Asakura M Marty R Dagher R Pazdur 《Annals of oncology》2006,17(6):889-896
PURPOSE: This paper summarizes the role of external advisors in oncology drug development and regulation from a global perspective. DESIGN: Recently, representatives from the United States Food and Drug Administration, European Medicines Agency, the Japanese Pharmaceuticals and Medical Devices Agency, the Australian Therapeutic Goods Administration and Health Canada held a meeting in conjunction with the American Society of Clinical Oncology meeting. The role of external advisors in oncology drug development and regulation in each of these jurisdictions was presented and discussed. RESULTS: All regulatory bodies described have experience with two forms of outside expertise: advice from individual experts and advice from a group of experts assembled as an advisory group. Regulatory jurisdictions use individual experts variably. In some regions, individual experts provide advice based on knowledge and experience during the drug development phase or in the planning phase for the submission of a drug registration package. In other regions, these individuals serve as external evaluators with the primary responsibility for the review of a clinical trials package submitted for drug registration. Advisory boards have been formalized in all jurisdictions discussed. Advisory boards have a role in discussing specific applications as well as broad policy issues. A common theme is a composition of a core panel of experts with augmentation by additional expertise as needed for consideration of specific scientific questions. In all jurisdictions, advisory board recommendations are not binding on the regulatory body. CONCLUSIONS: Global oncology drug development and registration involves the use of experts by regulatory authorities. The types of experts needed, the expert's role and the transparency of the advisory process reflect the individual needs in different regions. 相似文献
3.
J Mantz J Marty Y Pansard D Henzel A Loiseau M Pocidalo J Langlois J M Desmonts 《The Journal of thoracic and cardiovascular surgery》1990,99(1):75-81
To evaluate whether the function of beta-adrenergic receptors, essential to the biologic activity of catecholamines, is altered during coronary artery bypass grafting, we measured, in 16 patients undergoing myocardial revascularization, the density and the affinity of lymphocyte beta-adrenergic receptors before anesthesia induction (control) and at the end of cardiopulmonary bypass. Variations in the density and affinity of beta-adrenergic receptors were determined in vitro. Repeated determinations of plasma epinephrine and norepinephrine concentrations were also performed. Overall, no significant modification was observed in mean density and affinity of beta-adrenergic receptors at the end of cardiopulmonary bypass when compared with control values. However, a significant decrease (p less than 0.05) in affinity for isoproterenol was found in the six patients who had high catecholamine levels during cardiopulmonary bypass. In contrast, no significant modification of beta-adrenoreceptor affinity for isoproterenol was observed in the 10 patients who did not have this degree of adrenergic activation. In addition, beta-adrenoreceptor affinity for isoproterenol was decreased in the three patients in whom intraaortic balloon pumping was mandatory after discontinuation of cardiopulmonary bypass. We suggest that this decreased affinity of lymphocyte beta-adrenergic receptors could be related, at least in part, to a sustained adrenergic activation occurring in some patients during cardiopulmonary bypass. 相似文献
4.
Robert J. McDermott PhD CHE FASHA Wesley E. Hawkins PhD Phillip J. Marty PhD CHES Eliza Ames Littlefield PhD Susan Murray RN Thomas K. Williams EdD 《The Journal of school health》1990,60(8):414-417
Frequency of symptoms of depression and selected health-related practices and events were measured in a sample of 219 high school students. Students reported numerous symptoms of depression. Relative proportions of boys and girls reporting symptoms of depression were not significantly different. However, girls reported experiencing more severe depression than their male counterparts. Depression correlated significantly with several of the 22 health practices and states of affect examined. Both the determinants and manifestations of depression in adolescent cohorts require in-depth investigation. Possible implications for school health personnel are discussed. 相似文献
5.
High-performance liquid chromatography has been used to quantitate benzalkonium chloride (alkylbenzyldimethylammonium chloride) in complex ophthalmic formulations at or below concentration levels of 50 ppm. The method involves a one-step dilution for sample preparation and direct injection; therefore, recovery and/or conversion problems are nonexistent. The assay is quick, specific, reproducible, and simple. This new approach makes routine determinations far simpler than previous methods and is especially useful for product stability studies and quality control procedures. 相似文献
6.
7.
When an area of the adult rat CNS is depleted of neurons by an in situ excitotoxic injection, afferent axons to the area exhibit morphological alterations reminiscent of growth cones. These morphological changes are likely to be related to the deprivation of target cells. In addition, however, the area of neuronal loss is itself the site of profound changes in glial cell content, and altered axon-glial interactions may play a role in the axonal changes. In an attempt to define these interactions, we have undertaken a systemic study of glial populations in excitotoxically lesioned CNS over time. The microglial/macrophagic response is analysed in this paper; the astrocytic response is described in the companion paper [Dusart et al. (1991) Neuroscience 45, 541-549]. The microglial/macrophagic response was studied following kainic acid-induced neuronal loss in the thalamus of the adult rat. These microglial/macrophagic cells were labeled with the B4 isolectin from Griffonia simplicifolia, and the time-course of their response was studied between one day and one year post-lesion. This time-course study revealed different stages in the evolution of the response. At one day post-lesion, cell counts indicated that there was no increase in the number of non-neuronal cells in the neuron-depleted area. However, activated labeled cells were present in the entire thalamus on the side of the lesion, neuron-depleted or not. They were characterized by both increased lectin-binding and altered morphology when compared to quiescent microglia. In the absence of recruitment and/or proliferation, this result indicates that the early response consisted solely of the activation of resident microglia. By contrast, we observed a progressive increase in the number of non-neuronal cells in the lesion from four to 15 days post-lesion. A recruitment of blood-borne monocytes was apparent, and the observation of mitotic labeled cells indicated a proliferation of microglial/macrophagic cells in situ. There was a progressive decrease in the microglial/macrophagic reaction that began one month after lesion. In a thin band of parenchyma surrounding the neuron-depleted area, activated microglial/macrophagic cells were seen contacting neurons, and clusters of glial cells were observed around neurons up to one year post-lesion. These results suggest that neurons around the lesion site itself may be injured, secondarily, from a long term deleterious effect of the inflammatory process. This study allows us to conclude that activated microglia/macrophages are the predominant glial cell type in the excitotoxically lesioned CNS over the first weeks.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
8.
R J McDermott P D Sarvela P N Hoalt S M Bajracharya P J Marty E M Emery 《The Journal of school health》1992,62(4):146-150
A cross-sectional survey research design measured factors related to cigarette use among 2,212 senior high school students. Results showed 14.3% of the sample smoked cigarettes at least occasionally, with 5.3% reporting they were daily smokers. About 12.8% indicated they were ex-smokers. Males and females smoked at almost equal rates, and the percentage of 10th grade student smokers was slightly higher (16.4%) than the percentage of juniors and seniors who smoked. Approximately 22% of Hispanic students, 15% of Caucasian students, and 4.5% of African-American students reported smoking cigarettes at least occasionally. An initial regression analysis used 21 variables to predict cigarette smoking. A more parsimonious regression model (R2 = .28), using variables from the initial regression analysis with significance levels of .01 or less, indicated the most important predictors of cigarette use were ethnic group, attitude toward females who smoke, close friends' use of cigarettes, personal use of marijuana, best friend's use of cigarettes, personal use of alcohol, and school self-esteem. Implications for school health programs are addressed. 相似文献
9.
Jos F M de Jonghe Kees J Kalisvaart Marty Dijkstra Huib van Dis Ralph Vreeswijk Martin G Kat Piet Eikelenboom Tjeerd van der Ploeg Willem A van Gool 《The American journal of geriatric psychiatry》2007,15(2):112-121
OBJECTIVES: The authors investigated prodromal delirium symptoms in elderly patients undergoing hip surgery. METHODS: This was a prospective cohort study in the setting of a large medical school-affiliated general hospital in Alkmaar, The Netherlands. Participants were patients undergoing hip surgery aged 70 and older at risk for delirium. Before surgery, patients were randomized to low-dose prophylactic haloperidol treatment or placebo. Daily assessments were based on patient interviews with the Mini-Mental State Examination and Digit Span test. The Delirium Rating Scale-Revised (DRS-R-98) was used to measure early symptoms during the prodromal phase before the onset of delirium. RESULTS: Data of 66 patients with delirium were compared with those of 35 at-risk patients who did not develop delirium: 14 of 66 patients (21%) had delirium on the day of surgery or early the day after, 32 of 66 (48%) on the second day, 14 of 66 on the third, and six of 66 (9%) on the fourth. The average DRS-R-98 total scores on day -4 to day -1 before delirium were 1.9 for the comparison group patients and 5.0, 4.3, 5.8, and 10.7 for patients with postoperative delirium. Multivariate analysis showed that the early symptoms memory impairments, incoherence, disorientation, and underlying somatic illness predict delirium. CONCLUSIONS: Most elderly patients undergoing hip surgery with postoperative delirium already have early symptoms in the prodromal phase of delirium. These findings are potentially useful for screening purposes and for optimizing prevention strategies targeted at reducing the incidence of postoperative delirium. 相似文献