全文获取类型
收费全文 | 3137704篇 |
免费 | 247776篇 |
国内免费 | 6475篇 |
专业分类
耳鼻咽喉 | 44286篇 |
儿科学 | 102113篇 |
妇产科学 | 89406篇 |
基础医学 | 446318篇 |
口腔科学 | 91276篇 |
临床医学 | 281850篇 |
内科学 | 604900篇 |
皮肤病学 | 69132篇 |
神经病学 | 257190篇 |
特种医学 | 122734篇 |
外国民族医学 | 1050篇 |
外科学 | 472800篇 |
综合类 | 81123篇 |
现状与发展 | 7篇 |
一般理论 | 1157篇 |
预防医学 | 249466篇 |
眼科学 | 74208篇 |
药学 | 230972篇 |
5篇 | |
中国医学 | 6705篇 |
肿瘤学 | 165257篇 |
出版年
2018年 | 31899篇 |
2016年 | 27743篇 |
2015年 | 31731篇 |
2014年 | 44725篇 |
2013年 | 68047篇 |
2012年 | 91596篇 |
2011年 | 96815篇 |
2010年 | 57205篇 |
2009年 | 54361篇 |
2008年 | 90894篇 |
2007年 | 96853篇 |
2006年 | 97729篇 |
2005年 | 95180篇 |
2004年 | 92366篇 |
2003年 | 88618篇 |
2002年 | 85988篇 |
2001年 | 142470篇 |
2000年 | 146607篇 |
1999年 | 123752篇 |
1998年 | 36127篇 |
1997年 | 32541篇 |
1996年 | 32231篇 |
1995年 | 30815篇 |
1994年 | 28713篇 |
1993年 | 27016篇 |
1992年 | 98955篇 |
1991年 | 95652篇 |
1990年 | 93102篇 |
1989年 | 89543篇 |
1988年 | 83487篇 |
1987年 | 81916篇 |
1986年 | 77695篇 |
1985年 | 74694篇 |
1984年 | 56898篇 |
1983年 | 48765篇 |
1982年 | 29919篇 |
1981年 | 26871篇 |
1980年 | 25071篇 |
1979年 | 54253篇 |
1978年 | 38350篇 |
1977年 | 32283篇 |
1976年 | 30265篇 |
1975年 | 31859篇 |
1974年 | 39161篇 |
1973年 | 37680篇 |
1972年 | 35209篇 |
1971年 | 32879篇 |
1970年 | 30834篇 |
1969年 | 29167篇 |
1968年 | 26742篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Characteristics and outcome of patients with active pulmonary tuberculosis requiring intensive care.
R Erbes K Oettel M Raffenberg H Mauch M Schmidt-Ioanas H Lode 《The European respiratory journal》2006,27(6):1223-1228
Severe tuberculosis (TB) requiring intensive care unit (ICU) care is rare but commonly known to be of markedly bad prognosis. The present study aimed to describe this condition and to determine the mortality rate and risk factors associated with mortality. Patients with confirmed TB admitted to ICU between 1990 and 2001 were retrospectively identified and enrolled. Clinical, radiological and bacteriological data at admission and during hospital stay were recorded. A multivariate analysis was performed to identify the predictive factors for mortality. A total of 58 TB patients (12 females, mean age 48 yrs) admitted to ICU were included. Mean Acute Physiology and Chronic Health Evaluation (APACHE) II score at admission was 13.1+/-5.6 and 22 of 58 (37.9%) patients required mechanical ventilation. The in-hospital mortality was 15 of 58 (25.9%); 13 (22.4%) patients died in the ICU. The mean survival of patients who died was 53.6 days (range 1-229), with 50% of the patients dying within the first 32 days. The factors independently associated with mortality were: acute renal failure, need for mechanical ventilation, chronic pancreatitis, sepsis, acute respiratory distress syndrome, and nosocomial pneumonia. These data indicate a high mortality of patients with tuberculosis requiring intensive care unit care and identifies new independently associated risk factors. 相似文献
32.
33.
In cystic fibrosis (CF), perturbations of total daily energy expenditure (TDEE) may be a major determinant of altered nutrition and growth. Measurement of TDEE is problematic, though the flex-heart rate method (FHRM) provides a close estimation of TDEE, as compared to the cost-prohibitive, gold standard, the double-labeled water method, and permits estimates of the energy cost of daily activities (ECA) above resting energy expenditure (REE). We hypothesize that alterations in ECA affects TDEE in CF. PURPOSE: To measure components of TDEE in adolescents with CF and normal lung function compared with controls, and to determine whether ECA can be improved by diet and exercise. METHODS: Clinically stable CF subjects (aged 9-13, n=12) and age- and gender-matched controls (n=13) had repeated measurements of TDEE by FHRM, REE, and maximal cardiopulmonary exercise testing (CPET) during a 6-week exercise and diet program. RESULTS: While the mean REE was similar in both groups, ECA was significantly lower in CF adolescents as compared to controls (p=0.02). During CPET, maximal exercise in CF was characterized by hyperventilation, which was unrelated to ventilation-perfusion mismatching. There were no changes in REE after dietary intervention. CONCLUSION: ECA in CF adolescents with normal lung function is lower when compared to healthy controls. These findings support the hypothesis that clinically stable patients with CF have inefficient energy metabolism or alternatively conserve energy during activities of daily living. 相似文献
34.
35.
36.
37.
TG Berger F Kiesewetter C Maczek N Bauer M Lueftl G Schuler M Simon Jr 《Journal of the European Academy of Dermatology and Venereology》2006,20(2):178-183
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis. 相似文献
38.
39.
To determine if impaired energy metabolism might contribute to some aspects of Alzheimer disease (AD), including the vulnerability of the CA1 region of the hippocampal formation and the altered cytoskeleton evident in neurofibrillary tangles, we examined the effects of metabolic poisons on neuronal damage and cytoskeletal disruption in the hippocampal formation. Intrahippocampal injection of 3-nitropropionic acid (3-NP) and malonic acid resulted in neuronal death, particularly in CA1. Cytoskeletal disruption included loss of dendritic MAP2, but sparing of axonal τ. MK-801 (a noncompetitive NMDA receptor antagonist) did not atenuate the lesions produced by intrahippocampal injection of malonate. MK-801, however, was effective against intrastriatal malonate. Acute systemic 3-NP resulted in neuronal damage and cytoskeletal disruption in the CA1 region of the hippocampal formation, including an extensive loss of MAP2 immuno-reactivity, but sparing of τ. The neuronal loss in CA1 was delayed as compared to striatum. Chronic intraventricular infusion of 3-NP produced a different pattern of neuronal damage. Loss of τ-1 immuno-reactivity was observed in CA3 and CA1 s. oriens, whereas MAP2 immunostaining was preserved. These results demonstrate that chronic and acute administration of metabolic inhibitors produce distinct patterns of neuronal damage and cytoskeletal disruption. The results further suggest a differential involvement of the NMDA receptor in malonate-induced neuronal damage in striatum as compared to the hippocampus. The pattern of neuronal damage and cytoskeletal disruption observed following acute metabolic impairment resembled some aspects of neurofibrillary pathology in AD, but did not result in τ hyperphosphorylation. 相似文献
40.
Effects of poor glucose handling on arterial stiffness and left ventricular mass in normal children.
AIM: Cardiovascular risk factors can be present in children and young adults. We previously found abnormal microvascular function in children who had glucose intolerance and insulin resistance. The aim of the present study was to investigate whether they also have abnormalities in left ventricular mass (LVM) and arterial stiffness. METHODS: We measured heart dimensions and LVM using echocardiography, and arterial stiffness using pulse wave analysis in 23 children with good glucose handling (postfeeding glucose: 3.9 to 5 mmol/L) and 21 with poor glucose handling (7.7 to 11.4 mmol/L). RESULTS: The time to pulse reflection was slightly shorter in the poorer glucose handlers (mean+/-SD: 143+/-10 vs 153+/-20 ms, P=0.04), suggestive of increased arterial stiffness. Also in this group, there were significant relationships between intraventricular septal thickness, blood pressure and body mass index, but not in the normal glucose handlers. CONCLUSIONS: We have found that normal children who are in the lowest quintile of glucose tolerance in comparison with their peers are exhibiting the first signs of arterial stiffening. In addition, we have seen the beginnings of a relationship between blood pressure, body mass index and left ventricular enlargement in this group. While these changes may not yet be clinically significant, their emergence might be further evidence of early predisposition to cardiovascular disease. 相似文献