全文获取类型
收费全文 | 1915篇 |
免费 | 103篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 115篇 |
妇产科学 | 20篇 |
基础医学 | 342篇 |
口腔科学 | 40篇 |
临床医学 | 185篇 |
内科学 | 412篇 |
皮肤病学 | 9篇 |
神经病学 | 196篇 |
特种医学 | 58篇 |
外科学 | 177篇 |
综合类 | 19篇 |
预防医学 | 191篇 |
眼科学 | 17篇 |
药学 | 91篇 |
肿瘤学 | 141篇 |
出版年
2023年 | 14篇 |
2022年 | 34篇 |
2021年 | 36篇 |
2020年 | 28篇 |
2019年 | 33篇 |
2018年 | 22篇 |
2017年 | 43篇 |
2016年 | 37篇 |
2015年 | 50篇 |
2014年 | 58篇 |
2013年 | 87篇 |
2012年 | 137篇 |
2011年 | 136篇 |
2010年 | 61篇 |
2009年 | 75篇 |
2008年 | 146篇 |
2007年 | 127篇 |
2006年 | 147篇 |
2005年 | 101篇 |
2004年 | 110篇 |
2003年 | 132篇 |
2002年 | 109篇 |
2001年 | 29篇 |
2000年 | 18篇 |
1999年 | 28篇 |
1998年 | 24篇 |
1997年 | 17篇 |
1996年 | 9篇 |
1995年 | 16篇 |
1994年 | 11篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1972年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有2024条查询结果,搜索用时 15 毫秒
101.
End-stage chronic obstructive pulmonary disease often leads to hypercapnic respiratory failure. Oxygen supplementation therapy may further aggravate hypercapnia and not all patients are compliant with non-invasive ventilation. This case documents successful control of chronic respiratory failure with medroxyprogesterone in a postmenopausal woman during 1-year follow-up. 相似文献
102.
103.
Nairismägi J Gröhn OH Kettunen MI Nissinen J Kauppinen RA Pitkänen A 《Epilepsia》2004,45(9):1024-1034
PURPOSE: This study examined the hypothesis that neurodegeneration continues after status epilepticus (SE) ends and that the severity of damage at the early phase of the epileptogenic process predicts the outcome of epilepsy in a long-term follow-up. METHODS: SE was induced in rats by electrical stimulation of the amygdala, and the progression of structural alterations was monitored with multiparametric magnetic resonance imaging (MRI). Absolute T2, T1rho, and diffusion (Dav) images were acquired from amygdala, piriform cortex, thalamus, and hippocampus for < or = 4.5 months after SE. Frequency and type of spontaneous seizures were monitored with video-electroencephalography recordings. Histologic damage was assessed from Nissl, Timm, and Fluoro-Jade B preparations at 8 months. RESULTS: At the acute phase (2 days after SE induction), quantitative MRI revealed increased T2, T1rho, and Dav values in the primary focal area (amygdala), reflecting disturbed water homeostasis and possible early structural damage. Pathologic T2 and T1rho were observed in mono- or polysynaptically connected regions, including the piriform cortex, midline thalamus, and hippocampus. The majority of acute MRI abnormalities were reversed by 9 days after SE. In later time points (> 20 days after induction), both the T1rho and diffusion MRI revealed secondarily affected areas, most predominantly in the amygdala and hippocampus. At this time, animals began to have spontaneous seizures. The initial pathology revealed by MRI had a low predictive value for the subsequent severity of epilepsy and tissue damage. CONCLUSIONS: The results demonstrate progressive neurodegeneration after SE in the amygdala and the hippocampus and stress the need for continued administration of neuroprotectants in the treatment of SE even after electrographic seizure activity has ceased. 相似文献
104.
105.
106.
107.
Nemirov K Vapalahti O Papa A Plyusnina A Lundkvist A Antoniadis A Vaheri A Plyusnin A 《Journal of medical virology》2003,69(3):408-416
The first complete genome sequence of Dobrava hantavirus isolated from yellow-necked mouse Apodemus flavicollis trapped in the northeastern Greece is described. The S, M, and L segments of the Greek isolate of Dobrava virus are 1673, 3635, and 6532 nucleotides (nt) long, respectively, and encode the nucleocapsid (N) protein of 429 amino acids (aa), glycoprotein precursor of 1135 aa, and the L protein of 2151 aa. N protein contains three cysteine residues conserved in all known hantaviruses, as well as structural domains responsible for the RNA binding and presumable interaction with the apoptosis enhancer Daxx. All cysteine residues and glycosylation sites that are conserved among G1G2 sequences of all hantaviruses species were also found in the Greek isolate. The L protein contains all the polymerase motifs and structural domains found in other hantavirus polymerases. Comparison of the Greek isolate of Dobrava virus with other hantaviruses showed the highest level of sequence homology with Dobrava virus isolate from Slovenia. Other hantaviruses carried by Murinae rodents (Saaremaa, Hantaan, Seoul, and Thailand viruses) were more divergent and hantaviruses carried by Arvicolinae or Sigmodontinae rodents showed the highest genetic diversity with the Greek isolate of Dobrava. The results of phylogenetic analyses confirmed these observations and showed a monophily of all the Dobrava virus strains that, in turn, shared more ancient ancestors first with Saaremaa virus and then with other Murinae-borne hantaviruses. 相似文献
108.
STUDY OBJECTIVES: To predict the airflow dynamics during sleep using a mathematic model that incorporates a number of static and dynamic upper airway forces, and to compare the numerical results to clinical flow data recorded from patients with sleep-disordered breathing on and off various treatment options. DESIGN: Upper airway performance was modeled in virtual subjects characterized by parameter settings that describe common combinations of risk factors predisposing to upper airway collapse during sleep. The treatments effect were induced by relevant changes of the initial parameter values. SETTING: Computer simulations at our website (http://www.utu.fi/ml/sovmat/bio/). PARTICIPANTS: Risk factors considered in the simulation settings were sex, obesity, pharyngeal collapsibility, and decreased phasic activity of pharyngeal muscles. INTERVENTIONS: The effects of weight loss, pharyngeal surgery, nasal continuous positive airway pressure, and respiratory stimulation on the inspiratory flow characteristics were tested with the model. MEASUREMENTS AND RESULTS: Numerical predictions were investigated by means of 3 measurable inspiratory airflow characteristics: initial slope, total volume, and flow shape. The model was able to reproduce the inspiratory flow shape characteristics that have previously been described in the literature. Simulation results also supported the observations that a multitude of factors underlie the pharyngeal collapse and, therefore, certain medical therapies that are effective in some conditions may prove ineffective in others. CONCLUSIONS: A mathematic model integrating the current knowledge of upper airway physiology is able to predict individual treatment responses. The model provides a framework for designing novel and potentially feasible treatment alternatives for sleep-disordered breathing. 相似文献
109.
Ezrin immunoreactivity in relation to survival in serous ovarian carcinoma patients 总被引:27,自引:0,他引:27
OBJECTIVE: Ezrin is a membrane-cytoskeleton linker protein, which regulates cell polarity and signaling. Increased ezrin expression in astrocytomas and uveal melanomas is correlated with unfavorable prognostic factors and reduced patient survival. We investigated ezrin IR in normal ovarian surface epithelium and serous ovarian carcinomas, and its relation with clinical parameters and patient outcome. METHODS: Tissue microarray blocks were constructed of all serous ovarian carcinoma tissue samples removed at a primary operation in Helsinki University Central Hospital between 1964 and 1999 and of healthy ovarian tissue samples. Ezrin expression was assessed by indirect immunohistochemistry using a monoclonal 3C12 ezrin antibody. Tissue samples (n = 440) were scored for the intensity of ezrin immunoreactivity, and the scores were compared with patient age, the stage and grade of disease, and disease outcome. RESULTS: Healthy ovarian epithelium showed strong polarized ezrin immunoreactivity. In serous ovarian carcinoma, the reactivity varied from strong (15.0% of samples) to moderate (57.3%) or weak/negative (27.7%) and the subcellular distribution was typically diffuse. Weak or negative expression of ezrin was associated with shorter survival (P = 0.027) but also with an advanced age of the patients (P = 0.0001), and a higher histological grade of the disease (P = 0.032). In Cox multivariate survival analysis, ezrin immunoreactivity had no independent effect on survival, when controlling for the stage and grade of the disease, and patient age. CONCLUSIONS: In contrast with astrocytomas and uveal melanomas, negative or weak ezrin immunoreactivity in serous ovarian carcinoma correlates with poor patient outcome. 相似文献
110.
Kawashima S Peltomäki T Laine J Rönning O 《International journal of pediatric otorhinolaryngology》2002,63(2):119-127
OBJECTIVE: this study was aimed at characterizing the craniofacial structures, i.e. the facial skeleton, cranial base, dentition, pharyngeal airway space, and the hyoid bone position, in healthy preschool children without sleep-related breathing disorder. MATERIALS AND METHODS: from lateral cephalometric radiographs taken of 92 children for diagnostic purposes, 45 were selected for the present investigation on the basis of head position, and divided according to the classification of Siriwat and Jarabak (Angle Orthod. 55 (1985) 127) into groups representing counter-clockwise (CC), straight downward (SD), and clockwise (C) facial types. RESULTS: the findings showed that, in comparison with the other groups, CC is associated with larger facial taper and posterior facial height, smaller mandibular line angle, ramus position, lower facial height and cranial base angle. By a similar comparison, C is associated with larger mandibular line, gonial angles and convexity, and with a smaller L-1 to mandibular line angle. There were no significant differences in hyoid bone position among the three groups. However, the distance of the lower pharynx was smaller in CC than in C, while the tongue base of CC was noted to be in a posterior position. CONCLUSIONS: thus, the results indicate that there are significant differences in the madibular position and form among the present three groups of children. It is proposed that the objective of vertical facial control ought to be included in the treatment of preschool children with malocclusion and respiratory disorder. 相似文献