全文获取类型
收费全文 | 5465篇 |
免费 | 425篇 |
国内免费 | 72篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 162篇 |
妇产科学 | 224篇 |
基础医学 | 683篇 |
口腔科学 | 82篇 |
临床医学 | 464篇 |
内科学 | 1381篇 |
皮肤病学 | 120篇 |
神经病学 | 646篇 |
特种医学 | 183篇 |
外科学 | 605篇 |
综合类 | 7篇 |
一般理论 | 3篇 |
预防医学 | 318篇 |
眼科学 | 54篇 |
药学 | 389篇 |
中国医学 | 9篇 |
肿瘤学 | 592篇 |
出版年
2024年 | 14篇 |
2023年 | 130篇 |
2022年 | 282篇 |
2021年 | 441篇 |
2020年 | 252篇 |
2019年 | 283篇 |
2018年 | 328篇 |
2017年 | 210篇 |
2016年 | 237篇 |
2015年 | 263篇 |
2014年 | 275篇 |
2013年 | 331篇 |
2012年 | 438篇 |
2011年 | 356篇 |
2010年 | 196篇 |
2009年 | 149篇 |
2008年 | 254篇 |
2007年 | 257篇 |
2006年 | 222篇 |
2005年 | 187篇 |
2004年 | 180篇 |
2003年 | 147篇 |
2002年 | 123篇 |
2001年 | 37篇 |
2000年 | 29篇 |
1999年 | 42篇 |
1998年 | 30篇 |
1997年 | 19篇 |
1996年 | 21篇 |
1995年 | 16篇 |
1994年 | 19篇 |
1993年 | 12篇 |
1992年 | 12篇 |
1991年 | 19篇 |
1990年 | 16篇 |
1989年 | 11篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1984年 | 11篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1979年 | 17篇 |
1976年 | 5篇 |
1973年 | 5篇 |
1968年 | 2篇 |
1966年 | 2篇 |
1965年 | 2篇 |
排序方式: 共有5962条查询结果,搜索用时 15 毫秒
1.
2.
Anna Maria Lavezzi Giulia Ottaviani Lorella Terni Luigi Matturri 《International journal of developmental neuroscience》2006,24(6):365-371
The aim of this study was to investigate the histological and biological features of the human cerebellar cortex development and differentiation. We analyzed 52 brains of fetal and infant death victims, aged from 17 gestational weeks to 12th postnatal month. In particular, in the cerebellar cortex at different ages we evaluated, besides the structural aspects, the expression of several biomarkers implicated in proliferative processes (c-fos, PCNA and apoptosis). We observed morphological patterns progressively evolving every month, from the indefinite structure of the second gestational trimester to the four-layered structure (external granular layer, molecular layer, Purkinje cell layer, internal granular layer) of the late fetal cortex and subsequently to the three-layered postnatal definitive morphology, due to involution of the external granular layer. The evaluation of the biological features of the cerebellar cortex showed high proliferative activity mainly confined to the transient external granular layer in prenatal life, and high apoptotic index after birth. Thus, the histological examination, better with the support of biomarker investigations, allows with accuracy to describe the dynamic sequence of steps that occur in human cerebellar cortex development and to establish in each case the age, namely the pre- or postnatal month of life. Consequently, we can diagnose delayed or altered processes of differentiation during the development of the human cerebellar cortex. 相似文献
3.
4.
Francesco Leo Paolo Scanagatta Pierangelo Baglio Davide Radice Giulia Veronesi Piergiorgio Solli Francesco Petrella Lorenzo Spaggiari 《European journal of cardio-thoracic surgery》2007,31(5):780-782
OBJECTIVE: A higher mortality has been reported after pneumonectomy over the age of 70. The aim of the study was to quantify the additional risk due to age after standard pneumonectomy for lung cancer by a case-control study. METHODS: Our clinical database was reviewed to search for patients aged 70 years or more who underwent standard pneumonectomy for lung cancer between 1998 and 2005. A control group of patients younger than 70 (one case/two controls) was matched for sex, cardiovascular disease, American Association of Anaesthetists score, respiratory function, side of pneumonectomy, induction chemotherapy and stage. Overall mortality and morbidity were compared. Long-term survival data were also analysed. RESULTS: During the considered period, 35 patients aged 70 years or more underwent pneumonectomy (30 males, median age 73 years, 15 right-sided procedures). The control group was composed of 70 patients. The two groups were homogeneous in the variables used for matching. Overall mortality and morbidity were 11.4 and 54.2% in the elderly group as compared to 4.3 and 41.6% in controls (p-value not significant). Elderly patients experienced a higher rate of respiratory complications (25.7%) as compared to controls (8.3%, p=0.01). At univariate analysis, the only risk factor for death was the occurrence of respiratory complications (OR 6.5, CI 1.8-18.2). At multivariate analysis, age >or=70 years (OR 5.36, CI 1.48-19.3) and preoperative chemotherapy (OR 7.65, CI 2.04-28.6) were confirmed as predictors of respiratory complications. Five-year survival was 17.5% in the elderly group and 53.6% in the control group (p=0.003). Elderly patients with a better respiratory function (FEV1>70%) had a 5-year survival of 45.4%. CONCLUSIONS: In the elderly patients, the risk of respiratory complications after pneumonectomy is increased as compared to younger patients with equivalent respiratory function. Age and preoperative chemotherapy are independent risk factors for respiratory complications. A lower mortality and a better long-term survival are obtained in elderly patients with a better respiratory function (FEV1>or=70%). 相似文献
5.
6.
7.
Clinical, electrocardiographic and echocardiographic data were collected in a group of 228 patients with autosomal dominant polycystic kidney disease (PKD) and in another group of 146 unaffected members (NPKD) both comprised in a five-generation kindred followed for 10 years, in order to determine the profile and prevalence of cardiovascular derangement of the genetic disease. A family of 181 members was used as a control. The prevalence of left ventricular hypertrophy in the three groups was 24, 14 and 6% respectively (p less than 0.01); after 10 years it increased up to 35, 26 and 13% respectively (p less than 0.05). The evidence of mitral-valve prolapse was more frequent in PKD and in NPKD group (25 and 20% respectively) than in control subjects (2%) (p less than 0.0001). Mitral incompetence was found in 30, 18 and 8% of those groups respectively (p less than 0.002). The large difference in mitral involvement did not change over time. Tricuspid valve prolapse was detected in 5, 4 and 1% of the three groups, respectively (p less than 0.05). A small increase in frequency was found after 10 years only in polycystic kidney disease patients. Regurgitant aortic lesions were present in higher prevalence in PKD (19%) and NPKD (17%) members than in controls (5%) (p less than 0.001). After 10 years they were 23, 20 and 8%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
Nimodipine treatment in poor-grade aneurysm patients. Results of a multicenter double-blind placebo-controlled trial 总被引:4,自引:0,他引:4
K C Petruk M West G Mohr B K Weir B G Benoit F Gentili L B Disney M I Khan M Grace R O Holness 《Journal of neurosurgery》1988,68(4):505-517
A multicenter, randomized placebo-controlled double-blind trial of nimodipine in poor-grade aneurysm patients was carried out in 17 Canadian hospitals. Of 188 patients enrolled in the trial, 32 were excluded for protocol violations and two were excluded due to statistical considerations, leaving 154 patients for valid outcome analysis. Nimodipine treatment was associated with a significantly better outcome (p less than 0.001): 21 (29.2%) of 72 nimodipine-treated patients had a good outcome at 3 months after subarachnoid hemorrhage (SAH) compared to eight (9.8%) of 82 placebo-treated patients. Delayed ischemic deficits from vasospasm alone were significantly less frequent in the nimodipine group (p less than 0.05) with permanent deficits occurring in five nimodipine-treated patients (6.9%) and in 22 placebo-treated patients (26.8%). Improvement in the good outcome rate and reduction in delayed ischemic deficits from vasospasm alone occurred in both Grade 3 and 4 patients, with no difference between nimodipine- and placebo-treated patients being found in Grade 5 patients. Repeat angiography after Day 4 was carried out in 124 patients. There was no significant difference in the incidence of moderate or severe diffuse spasm, which was seen in 64.3% of nimodipine-treated patients and 66.2% of placebo-treated patients. The authors conclude that nimodipine treatment in poor-grade patients with SAH results in an increase in the number of good outcomes and a reduction in the incidence of delayed neurological deterioration due to vasospasm. This effect occurs by a mechanism other than prevention of large-vessel spasm as visualized on angiography. 相似文献
9.
10.
Fabio Piscaglia Valeria Camaggi Matteo Ravaioli Gian Luca Grazi Matteo Zanello Simona Leoni Giorgio Ballardini Giulia Cavrini Antonio Daniele Pinna Luigi Bolondi 《Liver transplantation》2007,13(6):857-866
The best prioritization of patients with hepatocellular carcinoma (HCC) waiting for liver transplantation under the model for end-stage liver disease (MELD) allocation system is still being debated. We analyzed the impact of a MELD adjustment for HCC, which consisted of the addition of an extra score (based on the HCC stage and waiting time) to the native MELD score. The outcome was analyzed for 301 patients with chronic liver disease listed for liver transplantation between March 1, 2001 and February 28, 2003 [United Network for Organ Sharing (UNOS)-Child-Turcotte-Pugh (CTP) era, 163 patients, 28.8% with HCC] and between March 1, 2003 and February 28, 2004 (HCC-MELD era, 138 patients, 29.7% with HCC). In the HCC-MELD era, the cumulative dropout risk at 6 months was 17.6% for patients with HCC versus 22.3% for those patients without HCC (P = NS), similar to that in the UNOS-CTP era. The cumulative probability of transplantation at 6 months was 70.3% versus 39.0% (P = 0.005), being higher than that in the UNOS-CTP era for patients with HCC (P = 0.02). At the end of the HCC-MELD era, 12 patients with HCC (29.3%) versus 57 without HCC (58.8%) were still on the list (P = 0.001). Both native and adjusted MELD scores were higher (P < 0.05) and progressed more in patients with HCC who dropped out than in those who underwent transplantation or remained on the list (the initial-final native MELD scores were 17.3-23.1, 15.5-15.6, and 12.8-14.1, respectively). The patients without HCC remaining on the list showed stable MELD scores (initial-final: 15.1-15.4). In conclusion, the present data support the strategy of including the native MELD scores in the allocation system for HCC. This model allows the timely transplantation of patients with HCC without severely affecting the outcome of patients without HCC. 相似文献