全文获取类型
收费全文 | 2887842篇 |
免费 | 209606篇 |
国内免费 | 10226篇 |
专业分类
耳鼻咽喉 | 39070篇 |
儿科学 | 92258篇 |
妇产科学 | 75072篇 |
基础医学 | 422359篇 |
口腔科学 | 79070篇 |
临床医学 | 264721篇 |
内科学 | 550750篇 |
皮肤病学 | 63426篇 |
神经病学 | 221250篇 |
特种医学 | 107880篇 |
外国民族医学 | 578篇 |
外科学 | 426446篇 |
综合类 | 79368篇 |
现状与发展 | 35篇 |
一般理论 | 969篇 |
预防医学 | 225395篇 |
眼科学 | 67533篇 |
药学 | 219422篇 |
96篇 | |
中国医学 | 12395篇 |
肿瘤学 | 159581篇 |
出版年
2021年 | 25625篇 |
2019年 | 24911篇 |
2018年 | 33780篇 |
2017年 | 26302篇 |
2016年 | 29213篇 |
2015年 | 34061篇 |
2014年 | 47549篇 |
2013年 | 69216篇 |
2012年 | 95202篇 |
2011年 | 100863篇 |
2010年 | 61868篇 |
2009年 | 57926篇 |
2008年 | 93492篇 |
2007年 | 99153篇 |
2006年 | 99690篇 |
2005年 | 95622篇 |
2004年 | 90812篇 |
2003年 | 87452篇 |
2002年 | 84058篇 |
2001年 | 132388篇 |
2000年 | 134904篇 |
1999年 | 112733篇 |
1998年 | 32689篇 |
1997年 | 28712篇 |
1996年 | 28803篇 |
1995年 | 27242篇 |
1994年 | 25035篇 |
1993年 | 23424篇 |
1992年 | 86249篇 |
1991年 | 84161篇 |
1990年 | 81928篇 |
1989年 | 79272篇 |
1988年 | 72880篇 |
1987年 | 71382篇 |
1986年 | 66964篇 |
1985年 | 63891篇 |
1984年 | 47465篇 |
1983年 | 40318篇 |
1982年 | 23677篇 |
1979年 | 43606篇 |
1978年 | 30981篇 |
1977年 | 25859篇 |
1976年 | 24770篇 |
1975年 | 26641篇 |
1974年 | 31881篇 |
1973年 | 30448篇 |
1972年 | 28520篇 |
1971年 | 26939篇 |
1970年 | 25112篇 |
1969年 | 23743篇 |
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
41.
M Vitacca M Paneroni L Bianchi E Clini A Vianello P Ceriana L Barbano B Balbi S Nava 《The European respiratory journal》2006,27(2):343-349
The present study compared four different sites and conditions for the measurement of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) in 38 spontaneous breathing tracheotomised patients. Of the patients, 28 had chronic obstructive pulmonary disease (COPD). The four different conditions were: 1) through a cuff inflated cannula (condition A); 2) through the mouth with a deflated cannula (condition B); 3) through the mouth with a phonetic uncuffed cannula (condition C); and 4) through the mouth after stoma closure (condition D). Five trials in each condition were performed using a standardised method. The measurement of both MIP and MEP differed significantly depending on the condition of measurement. MIP taken in condition A was significantly higher when compared with conditions B, C and D. MEP in condition A was significantly higher when compared with condition B and D. In condition A the highest frequency of the best measurement of MIP and MEP was observed at the fourth and fifth effort, respectively. The same results were obtained after the selection of only COPD patients. In conclusion, respiratory muscle assessment differs significantly depending on measurement condition. Measurement through inflated cannula tracheotomy yields higher values of both maximal inspiratory and maximal expiratory pressure. 相似文献
42.
A I D'hulst K R Bracke T Maes J L De Bleecker R A Pauwels G F Joos G G Brusselle 《The European respiratory journal》2006,28(1):102-112
Chronic obstructive pulmonary disease (COPD) is characterised by a local pulmonary inflammatory response to respiratory pollutants and by systemic inflammation. Tumour necrosis factor (TNF)-alpha has been implicated in systemic effects of COPD and operates by binding the p55 (R1) and p75 (R2) TNF-alpha receptors. To investigate the contribution of each TNF-alpha receptor in the pathogenesis of COPD, the present study examined the effects of chronic air or cigarette smoke (CS) exposure in TNF-alpha R1 knockout (KO) mice, TNF-alpha R2 KO mice and wild type (WT) mice. CS was found to significantly increase the protein levels of soluble TNF-alpha R1 (by four-fold) and TNF-alpha R2 (by 10-fold) in the bronchoalveolar lavage of WT mice. After 3 months, CS induced a prominent pulmonary inflammatory cell influx in WT and TNF-alpha R1 KO mice. In TNF-alpha R2 KO mice, CS-induced pulmonary inflammation was clearly attenuated. After 6 months, no emphysema was observed in CS-exposed TNF-alpha R2 KO mice in contrast to WT and TNF-alpha R1 KO mice. CS-exposed WT and TNF-alpha R1 KO mice failed to gain weight, whereas the body mass of TNF-alpha R2 KO mice was not affected. These current findings suggest that both tumour necrosis factor-alpha receptors contribute to the pathogenesis of chronic obstructive pulmonary disease, but tumour necrosis factor-alpha receptor-2 is the most active receptor in the development of inflammation, emphysema and systemic weight loss in this murine model of chronic obstructive pulmonary disease. 相似文献
43.
44.
45.
46.
47.
Bethe A Scalettar 《The Neuroscientist》2006,12(2):164-176
Neurons and related cell types often contain two major classes of neurosecretory vesicles, synaptic vesicles (SVs) and dense-core granules (DCGs), which store and release distinct cargo. SVs store and release classic neurotransmitters, which facilitate propagation of action potentials across the synaptic cleft, whereas DCGs transport, store, and release hormones, proteins, and neuropeptides, which facilitate neuronal survival, synaptic transmission, and learning. Over the past few years, there has been a major surge in our understanding of many of the key molecular mechanisms underlying cargo release from SVs and DCGs. This surge has been driven largely by the use of fluorescence microscopy (especially total internal reflection fluorescence microscopy) to visualize SVs or DCGs in living cells. This review highlights some of the recent insights into cargo release from neurosecretory vesicles provided by fluorescence microscopy, with emphasis on DCGs. 相似文献
48.
49.
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
50.
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