全文获取类型
收费全文 | 3700篇 |
免费 | 256篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 199篇 |
妇产科学 | 64篇 |
基础医学 | 524篇 |
口腔科学 | 69篇 |
临床医学 | 442篇 |
内科学 | 877篇 |
皮肤病学 | 92篇 |
神经病学 | 224篇 |
特种医学 | 451篇 |
外科学 | 242篇 |
综合类 | 48篇 |
预防医学 | 264篇 |
眼科学 | 26篇 |
药学 | 281篇 |
2篇 | |
肿瘤学 | 205篇 |
出版年
2023年 | 11篇 |
2022年 | 18篇 |
2021年 | 34篇 |
2020年 | 44篇 |
2019年 | 38篇 |
2018年 | 78篇 |
2017年 | 49篇 |
2016年 | 51篇 |
2015年 | 65篇 |
2014年 | 103篇 |
2013年 | 144篇 |
2012年 | 137篇 |
2011年 | 160篇 |
2010年 | 147篇 |
2009年 | 138篇 |
2008年 | 137篇 |
2007年 | 181篇 |
2006年 | 133篇 |
2005年 | 137篇 |
2004年 | 109篇 |
2003年 | 97篇 |
2002年 | 119篇 |
2001年 | 92篇 |
2000年 | 87篇 |
1999年 | 89篇 |
1998年 | 145篇 |
1997年 | 174篇 |
1996年 | 154篇 |
1995年 | 130篇 |
1994年 | 130篇 |
1993年 | 108篇 |
1992年 | 66篇 |
1991年 | 74篇 |
1990年 | 60篇 |
1989年 | 78篇 |
1988年 | 62篇 |
1987年 | 54篇 |
1986年 | 63篇 |
1985年 | 56篇 |
1984年 | 41篇 |
1983年 | 25篇 |
1982年 | 31篇 |
1981年 | 31篇 |
1980年 | 29篇 |
1979年 | 11篇 |
1978年 | 15篇 |
1977年 | 21篇 |
1976年 | 26篇 |
1975年 | 15篇 |
1970年 | 5篇 |
排序方式: 共有4031条查询结果,搜索用时 15 毫秒
31.
32.
The patellofemoral joint was imaged with magnetic resonance (MR) in the axial plane while the knee was positioned from 0 degrees to 32 degrees of flexion (nine positions). These multiple sequential images obtained within the early phases of flexion of the knee were viewed in a "cine-loop" format, producing a kinematic study that clearly demonstrated the relationship of the patella to the trochlear groove. Four healthy subjects and one patient with known bilateral subluxing patellae were studied. The preliminary results suggest that kinematic MR imaging of the patellofemoral joint is potentially useful for the evaluation of patellar tracking abnormalities. 相似文献
33.
Tortoriello DV; McGovern PG; Colon JM; Loughlin J; Santoro N 《Human reproduction (Oxford, England)》1998,13(11):3005-3008
We report an instance of critical ovarian hyperstimulation syndrome in a
highly responsive in-vitro fertilization patient despite the preventive
measure of a 4 day 'coast' interval during which no gonadotrophins were
administered while gonadotrophin-releasing hormone agonist therapy
continued until serum oestradiol concentrations fell below 3000 pg/ml.
相似文献
34.
35.
Smits PH Bakker R Jong E Mulder JW Meenhorst PL Kleter B van Doorn LJ Quint WG 《Journal of clinical microbiology》2005,43(12):5936-5939
Infection with human immunodeficiency virus (HIV) and the resulting immunosuppression are associated with an increased risk for human papillomavirus (HPV) persistence and related malignancies. In the present study we investigated the prevalence of HPV in urine samples from 104 HIV-infected men with low CD4+ cell counts (<100 per mm(3)) and 115 urine samples from HIV-negative men. A high prevalence of HPV DNA (39.4%) was found in the HIV patients. Most of the HPV types were high risk (81.4%), with HPV 52 as the most prevalent type (12.5%), followed by HPV 18 (6.7%), HPV 35 (5.8%), and HPV 70 (4.8%). Multiple HPV genotypes were observed in 17 (41%) of the 41 HPV- and HIV-positive men. In contrast, only 11 (9.6%) HPV DNA-positive cases were observed among the 115 HIV-uninfected men, and 3 (27.3%) contained multiple genotypes. Quantitative analyses indicated that the HPV viral load, as measured in urine samples, is significantly higher in HIV-positive men compared to HIV-negative men. In the present study we show that urine samples are useful for detecting HPV DNA, there is a high prevalence of HPV in HIV-positive men, and the HPV viral load is substantially higher in HIV-positive than in HIV-negative men. More studies are needed to evaluate the risk and natural development of HPV-related malignancies in HIV-positive men. 相似文献
36.
Incidence and determinants of moderate COPD (GOLD II) in male smokers aged 40–65 years: 5-year follow up
下载免费PDF全文
![点击此处可从《The British journal of general practice》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roeland MM Geijer Alfred PE Sachs Theo JM Verheij Philippe L Salom Jan-Willem J Lammers Arno W Hoes 《The British journal of general practice》2006,56(530):656-661
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major health problem with an estimated prevalence of 10-15% among smokers. The incidence of moderate COPD, as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), is largely unknown. AIM: To determine the cumulative incidence of moderate COPD (forced expiratory volume in 1 second/forced vital capacity ratio [FEV1/FVC] <0.7 and FEV1 <80% predicted) and its association with patient characteristics in a cohort of male smokers. DESIGN: Prospective cohort study. SETTING: The city of IJsselstein, a small town in the Netherlands. METHOD: Smokers aged 40-65 years who were registered with local GPs, participated in a study to identify undetected COPD. Baseline measurements were taken in 1998 of 399 smokers with normal spirometry (n = 292) or mild COPD (FEV1/FVC <0.7 and FEV1 >or=80% predicted, n = 107) and follow-up measurements were conducted in 2003. RESULTS: After a mean follow-up of 5.2 years, 33 participants developed moderate COPD (GOLD II). This showed an estimated cumulative incidence of 8.3% (95% CI = 5.8 to 11.4) and a mean annual incidence of 1.6%. No participant developed severe airflow obstruction. The risk of developing moderate COPD in smokers with baseline mild COPD (GOLD I) was five times higher than in those with baseline normal spirometry (one in five versus one in 25). CONCLUSIONS: In a cohort of middle-aged male smokers, the estimated cumulative incidence of moderate COPD (GOLD II) over 5 years was relatively high (8.3%). Age, childhood smoking, cough, and one or more GP contacts for lower respiratory tract problems were independently associated with incident moderate COPD. 相似文献
37.
38.
39.
M Avellanet RM Mirapeix D Escudero C Riera JM Domenech-Mateu 《Surgical and radiologic anatomy : SRA》1996,18(4):271-273
Summary We present a case with a characteristic magnetic resonance image (MRI) of bilateral open-lipped schizencephaly and atypical clinical presentation. The patient is still alive and in good health in her forties, she has never presented seizures, and although the motor dysfunction is well correlated with cerebral lobe involvement, neurobehavioral dysfunction is not proportional to the MR image of the cerebral malformation.
Un cas inhabituel de schizencéphalie bilatérale
Résumé Nous présentons un cas de schizencéphalie bilatérale ouverte caractérisé par une présentation clinique atypique et une imagerie par résonance magnétique nucléaire caractéristique. La patiente est encore vivante, en bonne santé, à plus de 40 ans, elle n'a jamais présenté de crise comitiale et, bien que les troubles moteurs soient bien corrélés aux altérations cérébrales, les troubles neuro-comportementaux ne sont pas proportionnels aux images IRM de cette malformation cérébrale.相似文献
40.
Pernelle A Smits Laurel S Kleppe Tyra A Witt Cheri S Mueske Richard G Vile Robert D Simari 《Endothelium》2007,14(1):1-5
Cells with an endothelial phenotype can be cultured from peripheral blood. These cells include cells of a monocytic origin with endothelial features (culture-modified mononuclear cells, CMMCs) and, at later time points, blood outgrowth endothelial cells (BOECs). Both are promising candidates for systemic cell-based cardiovascular therapies and each may have unique capabilities. Indeed, the combined use of both cell types has been shown to have synergistic therapeutic features requiring simultaneous delivery. However, the majority of preclinical studies of cell delivery have used splenectomized animals to increase systemic distribution. The goal of this study was to directly compare the distribution of these two cell types following systemic delivery in an intact animal model. A similar pattern of delivery was seen following delivery of both cell types with detection in the lung, liver, bone marrow, and spleen. Taken together, the data suggest that strategies using systemic delivery of circulation-derived cells must consider the distribution and efficiency of delivery in intact animals. 相似文献