全文获取类型
收费全文 | 50936篇 |
免费 | 2998篇 |
国内免费 | 246篇 |
专业分类
耳鼻咽喉 | 630篇 |
儿科学 | 1174篇 |
妇产科学 | 1221篇 |
基础医学 | 7077篇 |
口腔科学 | 1499篇 |
临床医学 | 5577篇 |
内科学 | 10973篇 |
皮肤病学 | 797篇 |
神经病学 | 5017篇 |
特种医学 | 1777篇 |
外科学 | 6305篇 |
综合类 | 325篇 |
一般理论 | 44篇 |
预防医学 | 3622篇 |
眼科学 | 805篇 |
药学 | 3441篇 |
1篇 | |
中国医学 | 59篇 |
肿瘤学 | 3836篇 |
出版年
2023年 | 321篇 |
2022年 | 630篇 |
2021年 | 1143篇 |
2020年 | 745篇 |
2019年 | 980篇 |
2018年 | 1194篇 |
2017年 | 1069篇 |
2016年 | 1255篇 |
2015年 | 1310篇 |
2014年 | 1739篇 |
2013年 | 2504篇 |
2012年 | 3793篇 |
2011年 | 3982篇 |
2010年 | 2367篇 |
2009年 | 2160篇 |
2008年 | 3288篇 |
2007年 | 3591篇 |
2006年 | 3204篇 |
2005年 | 3264篇 |
2004年 | 3007篇 |
2003年 | 2800篇 |
2002年 | 2569篇 |
2001年 | 431篇 |
2000年 | 352篇 |
1999年 | 487篇 |
1998年 | 563篇 |
1997年 | 462篇 |
1996年 | 408篇 |
1995年 | 348篇 |
1994年 | 305篇 |
1993年 | 310篇 |
1992年 | 236篇 |
1991年 | 230篇 |
1990年 | 210篇 |
1989年 | 222篇 |
1988年 | 195篇 |
1987年 | 171篇 |
1986年 | 177篇 |
1985年 | 210篇 |
1984年 | 181篇 |
1983年 | 167篇 |
1982年 | 192篇 |
1981年 | 159篇 |
1980年 | 139篇 |
1979年 | 112篇 |
1978年 | 123篇 |
1977年 | 131篇 |
1976年 | 94篇 |
1975年 | 107篇 |
1974年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
Andrea von Berg Renate Engelstätter Predrag Minic Miodrag Sréckovic Maria Luz Garcia Garcia Tadeusz Lato Jan H. Vermeulen Stefan Leichtl Stefan Hellbardt Thomas D. Bethke 《Pediatric allergy and immunology》2007,18(5):391-400
Ciclesonide is an onsite-activated inhaled corticosteroid (ICS) for the treatment of asthma. This study compared the efficacy, safety and effect on quality of life (QOL) of ciclesonide 160 microg (ex-actuator; nominal dose 200 microg) vs. budesonide 400 microg (nominal dose) in children with asthma. Six hundred and twenty-one children (aged 6-11 yr) with asthma were randomized to receive ciclesonide 160 microg (ex-actuator) once daily (via hydrofluoroalkane metered-dose inhaler and AeroChamber Plus spacer) or budesonide 400 microg once daily (via Turbohaler) both given in the evening for 12 wk. The primary efficacy end-point was change in forced expiratory volume in 1 s (FEV1). Additional measurements included change in daily peak expiratory flow (PEF), change in asthma symptom score sum, change in use of rescue medication, paediatric and caregiver asthma QOL questionnaire [PAQLQ(S) and PACQLQ, respectively] scores, change in body height assessed by stadiometry, change in 24-h urinary cortisol adjusted for creatinine and adverse events. Both ciclesonide and budesonide increased FEV1, morning PEF and PAQLQ(S) and PACQLQ scores, and improved asthma symptom score sums and the need for rescue medication after 12 wk vs. baseline. The non-inferiority of ciclesonide vs. budesonide was demonstrated for the change in FEV1 (95% confidence interval: -75, 10 ml, p = 0.0009, one-sided non-inferiority, per-protocol). In addition, ciclesonide and budesonide showed similar efficacy in improving asthma symptoms, morning PEF, use of rescue medication and QOL. Ciclesonide was superior to budesonide with regard to increases in body height (p = 0.003, two-sided). The effect on the hypothalamic-pituitary-adrenal axis was significantly different in favor of ciclesonide treatment (p < 0.001, one-sided). Both ciclesonide and budesonide were well tolerated. Ciclesonide 160 microg once daily and budesonide 400 microg once daily were effective in children with asthma. In addition, in children treated with ciclesonide there was significantly less reduction in body height and suppression of 24-h urinary cortisol excretion compared with children treated with budesonide after 12 wk. 相似文献
64.
Nan-Fu Chen Yeou-Chih Wang Chiung-Chyi Shen Yee-Jee Jan Wen-Hsien Chen Ching-Hsiang Leu 《Journal of clinical neuroscience》2004,11(5):527-530
We report a case of calcified chronic encapsulated intracerebral haematoma (ICH) in a 29-year-old female who presented with progressive left sided weakness and intermittent seizures since childhood. The preoperative magnetic resonance (MR) imaging of the head initially suggested that a partially thrombosed aneurysm or vascular malformation was present. However, no vascular stain was found on the digital subtraction angiography (DSA) of both the carotid and vertebral arteries. The excised mass was histologically diagnosed as a chronic ICH. We traced the patient's medical history and found that at the age of one she sustained a head injury after a fall. So far, to our knowledge, no case of epilepsy secondary to a calcified chronic encapsulated ICH occurring 28 years after head injury has been reported. Calcified chronic encapsulated ICH concomitant with new bone formation within is even rarer. The possible pathogenesis of this case is discussed. 相似文献
65.
Expression profiling identifies the CRH/CRH-R1 system as a modulator of neurovascular gene activity.
Jan M Deussing Claudia Kühne Benno Pütz Markus Panhuysen Johannes Breu Mary P Stenzel-Poore Florian Holsboer Wolfgang Wurst 《Journal of cerebral blood flow and metabolism》2007,27(8):1476-1495
Corticotropin-releasing hormone receptor type 1 (CRH-R1)-deficient mice display reduced anxiety-like behavior, a chronic corticosterone deficit, and an impaired neuroendocrine stress response caused by disruption of the hypothalamic-pituitary-adrenocortical (HPA) axis. The molecular substrates and pathways of CRH/CRH-R1-dependent signaling mechanisms underlying the behavioral phenotype as well as the consequences of lifelong glucocorticoid deficit remain largely obscure. To dissect involved neuronal circuitries, we performed comparative expression profiling of brains of CRH-R1 mutant and wild-type mice using our custom made MPIP (Max Planck Institute of Psychiatry) 17k cDNA microarray. Microarray analysis yielded 107 genes showing altered expression levels when comparing CRH-R1 knockout mice with wild-type littermates. A significant proportion of differentially expressed genes was related to control of HPA and hypothalamic-pituitary-thyroid (HPT) axes reflecting not only the disturbance of the HPA axis in CRH-R1 mutant mice but also the interplay of both neuroendocrine systems. The spatial analysis of regulated genes revealed a prevalence for genes expressed in the cerebral microvasculature. This phenotype was confirmed by the successful cross-validation of regulated genes in CRH overexpressing mice. Analysis of the cerebral vasculature of CRH-R1 mutant and CRH overexpressing mice revealed alterations of functional rather than structural properties. A direct role of the CRH/CRH-R1 system was supported by demonstrating Crhr1 expression in the adult murine cerebral vasculature. In conclusion, these data suggest a novel, previously unknown role of the CRH/CRH-R1 system in modulating neurovascular gene expression and function. 相似文献
66.
67.
Impact of randomized trials comparing conventional and endovascular abdominal aortic aneurysm repair on clinical practice. 总被引:1,自引:0,他引:1
Annette F Baas Diederick E Grobbee Jan D Blankensteijn 《Journal of endovascular therapy》2007,14(4):536-540
PURPOSE: To report a retrospective study into the effects of trials on clinical decision-making regarding abdominal aortic aneurysm (AAA) patients suitable for both conventional open (OR) and endovascular aneurysm repair (EVAR). METHODS: A questionnaire was sent to 1400 Dutch surgeons and trainees. Interviewees had to choose between OR and EVAR for AAA patients with and without comorbidity. Specifically, their preferences before and after the publication of 2 randomized trials (EVAR-1 and DREAM) were polled. RESULTS: Of the 524 (37%) questionnaires returned, 223 (43%) respondents treated AAA patients. Before publication of the trials, 160 (72%) preferred OR for the patient without comorbidity and 169 (76%) preferred EVAR for the patient with comorbidity. In total, 72 (32%) respondents changed their preference after the trials were published; however, there was no overall major shift. Focusing on the different cases revealed that the OR preference was significantly enhanced for the patient without comorbidity (p<0.01), while the EVAR preference was significantly enhanced for the patient with comorbidity (p<0.05). CONCLUSION: The randomized trials have not induced major overall changes in surgical decision-making for AAA patients suitable for both EVAR and OR. 相似文献
68.
ABSTRACT:Background: In 1996 a new model of maternity care characterized by continuity of midwifery care from early pregnancy through the postpartum period was implemented for women attending Monash Medical Centre, a tertiary level obstetric service, in Melbourne, Australia. This study's purpose was to assess the impact of this model on women's views and experiences of care during the antenatal, intrapartum, and postpartum periods compared with views of women receiving standard maternity care. Methods: One thousand low‐ and high‐risk women who booked at the antenatal clinic and met the eligibility criteria were randomly allocated to continuity of midwifery care from a group of seven midwives in collaboration with medical staff, or to standard care from a variety of midwives and medical staff. Women's views of care were measured by means of a postal questionnaire at four months after the birth. Results: Team midwifery care was associated with increased satisfaction with antenatal, intrapartum, and some aspects of postpartum care. The differences were most obvious for antenatal care. Conclusions: Continuity of midwifery care is realistically achievable in a tertiary obstetric referral service and is associated with increased satisfaction. (BIRTH 30:1 March 2003) 相似文献
69.
Markus Kamler Jan Goedeke Nikolaus Pizanis Vitaliy Milekhin Fritz-Ulrich Schade Heinz Jakob 《European journal of cardio-thoracic surgery》2005,28(2):259-265
OBJECTIVE: Induced hypothermia has been shown to be protective during cardiac surgery, but also in traumatic, ischemic, burn, and neurological injury. In previous in vivo animal experiments, we documented increased leukocyte/endothelial (L/E) cell interaction following normothermic extracorporeal blood circulation (ECC). This study was carried out to investigate whether reduced core temperature during ECC affects the damage to the microcirculation as evidenced by leukocyte adherence and edema formation. METHODS: Intravital fluorescence microscopy was used on the dorsal skinfold chamber preparation in Syrian golden hamsters. ECC was introduced via a micro-rollerpump (1 ml/min) and a 60 cm silicon tube (1mm inner diameter) shunted between the carotid artery and the jugular vein after application of 300IE Heparin/kg per body weight. Experiments were performed in chronically instrumented, awake animals (age 10-14 weeks, weight 65-75 g). Animals of the experimental group were cooled to 18 degrees C body temperature while ECC, followed by a rewarming period (n=7), controls experienced ECC under normothermia (37 degrees C, n=7). RESULTS: 30 min ECC at 18 degrees C resulted in a decrease of rolling and adherent leucocytes (stickers) in postcapillary venules after 1, 4 and 8h compared with the control group (119+/-46 vs. 274+/-113 n/mm2, P<0.05, mean+/-SD; n=7 in each group). Functional capillary density was significantly reduced during hypothermia (80+/-16 vs. 148+/-16 cm/cm2, P<0.05), but restored after rewarming. In contrast, edema formation was markedly increased during hypothermia. CONCLUSIONS: Hypothermia during ECC significantly reduced L/E cell interaction in the early post-ECC period. Hypothermia markedly reduced microvascular perfusion, but was completely restored upon rewarming. Despite a reduced number of adherent leukocytes, no protection of endothelial barrier function was seen as a consequence of induced hypothermia. 相似文献
70.
Jens Garbade Andreas Schubert Ardawan Julian Rastan Dominik Lenz Thomas Walther Jan Fritz Gummert Stefan Dhein Friedrich-Wilhelm Mohr 《European journal of cardio-thoracic surgery》2005,28(5):685-691
OBJECTIVE: Recent studies have demonstrated that transplanted bone marrow-derived stem cells (BMCs) possess a broad differentiation potential and are able to form new cardiomyocytes. However, the identity of BMCs as true cardiomyocytes is still ambiguous. Therefore, we investigated the fate of transplanted fluorescence labeled BMCs and cardiomyocytes in co-culture. METHODS: For cell tracking we used two different fluorescent probes, Vybrant/DiO and Vybrant/DiI. BMCs were taken from human sternal marrow, purified using a Ficoll-gradient-centrifugation, treated with 5-azacytidine and stained with Vybrant/DiO. Furthermore, isolated spontaneous beating cardiomyocytes of neonatal rats (CM) were labeled with Vybrant/DiI. Thereafter, the BMCs were transplanted into CM-cultures and investigated on day 1, 4, 7, 14 and 28 using two-color fluorescence phenotyping by laser-scanning-cytometry (LSC). Two-color positive cells were harvested by patch-clamp technique and beta-MHC mRNA expression was analyzed by single-cell PCR. RESULTS: Two different morphological phenotypes were observed by LSC. First, isolated DiO labeled BMCs without contact or with direct cell contact to DiI labeled CMs. Second, some BMCs and CMs were double positive for DiO/DiI spontaneously forming hybrids. This population increased by 18% from day 1 to 4 and decreased only slightly until day 28. Additionally, few two-color positive cell formations expressed both human and rat specific beta-MHC mRNA as well as only human beta-MHC mRNA indicating that cell-fusion and transdifferentiation has occurred. CONCLUSION: These observations provide in vitro evidence for spontaneous cell fusion and transdifferentiation of BMCs in co-culture, raising the possibility that the observed phenomenons may contribute to development or maintenance of these cell types. 相似文献