全文获取类型
收费全文 | 62568篇 |
免费 | 6001篇 |
国内免费 | 2313篇 |
专业分类
耳鼻咽喉 | 560篇 |
儿科学 | 1288篇 |
妇产科学 | 1213篇 |
基础医学 | 7600篇 |
口腔科学 | 1222篇 |
临床医学 | 7538篇 |
内科学 | 11230篇 |
皮肤病学 | 1132篇 |
神经病学 | 3727篇 |
特种医学 | 2142篇 |
外国民族医学 | 23篇 |
外科学 | 7499篇 |
综合类 | 5949篇 |
现状与发展 | 5篇 |
一般理论 | 35篇 |
预防医学 | 4180篇 |
眼科学 | 2251篇 |
药学 | 5650篇 |
46篇 | |
中国医学 | 2489篇 |
肿瘤学 | 5103篇 |
出版年
2024年 | 189篇 |
2023年 | 920篇 |
2022年 | 2041篇 |
2021年 | 2754篇 |
2020年 | 2011篇 |
2019年 | 1920篇 |
2018年 | 2112篇 |
2017年 | 1845篇 |
2016年 | 1880篇 |
2015年 | 2511篇 |
2014年 | 3039篇 |
2013年 | 3228篇 |
2012年 | 4343篇 |
2011年 | 4689篇 |
2010年 | 2874篇 |
2009年 | 2506篇 |
2008年 | 3333篇 |
2007年 | 3299篇 |
2006年 | 3221篇 |
2005年 | 3092篇 |
2004年 | 2432篇 |
2003年 | 2275篇 |
2002年 | 2002篇 |
2001年 | 1551篇 |
2000年 | 1490篇 |
1999年 | 1346篇 |
1998年 | 618篇 |
1997年 | 539篇 |
1996年 | 415篇 |
1995年 | 376篇 |
1994年 | 340篇 |
1993年 | 283篇 |
1992年 | 564篇 |
1991年 | 534篇 |
1990年 | 526篇 |
1989年 | 475篇 |
1988年 | 442篇 |
1987年 | 429篇 |
1986年 | 376篇 |
1985年 | 309篇 |
1984年 | 227篇 |
1983年 | 167篇 |
1982年 | 100篇 |
1981年 | 102篇 |
1980年 | 103篇 |
1979年 | 168篇 |
1978年 | 98篇 |
1977年 | 83篇 |
1976年 | 84篇 |
1975年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Henry Ho‐Lung Chan 《Clinical & experimental optometry》2005,88(6):410-414
The first‐order kernel analysis in multifocal electroretinogram (mfERG) using low contrast stimulation is suggested as a way to detect the inner retinal responses in animal studies. In this case report, this protocol is applied to human patients with glaucoma to demonstrate the possibility of using mfERG as a tool to detect glaucomatous damage. Two patients with glaucoma were recruited and had mfERG measurements with the 103‐scaled hexagonal stimulus pattern at low (50 per cent) contrast. Their responses were analysed and compared with those from normal subjects with the mfERG measured under the same condition. In the normal subjects, there were obvious oscillatory components on the ascending and descending limbs of the first‐order kernel response to 50 per cent contrast. In the glaucomatous patients, the oscillatory component on the descending limb was obviously diminished. In addition, this component was significantly diminished in the quadrant with a glaucomatous visual field defect. This suggests that the low‐contrast stimulation condition in mERG measurement may provide a good way to detect glaucomatous damage and this may help in clinical diagnosis of glaucoma. 相似文献
52.
Factors influencing family physicians to enter rural practice: Does rural or urban background make a difference?
下载免费PDF全文
![点击此处可从《Canadian family physician Médecin de famille canadien》网站下载免费的PDF全文](/ch/ext_images/free.gif)
53.
Digital mammography. ROC studies of the effects of pixel size and unsharp-mask filtering on the detection of subtle microcalcifications 总被引:3,自引:0,他引:3
H P Chan C J Vyborny H MacMahon C E Metz K Doi E A Sickles 《Investigative radiology》1987,22(7):581-589
We investigated the spatial resolution requirement and the effect of unsharp-mask filtering on the detectability of subtle microcalcifications in digital mammography. Digital images were obtained by digitizing conventional screen-film mammograms with a 0.1 X 0.1 mm2 pixel size, processed with unsharp masking, and then reconstituted on film with a Fuji image processing/simulation system (Fuji Photo Film Co., Tokyo, Japan). Twenty normal cases and 12 cases with subtle microcalcifications were included. Observer performance experiments were conducted to assess the detectability of subtle microcalcifications in the conventional, the unprocessed digital, and the unsharp-masked mammograms. The observer response data were evaluated using receiver operating characteristic (ROC) and LROC (ROC with localization) analyses. Our results indicate that digital mammograms obtained with 0.1 X 0.1 mm2 pixels provide lower detectability than the conventional screen-film mammograms. The detectability of microcalcifications in the digital mammograms is improved by unsharp-mask filtering; the processed mammograms still provide lower accuracy than the conventional mammograms, however, chiefly because of increased false-positive detection rates for the processed images at each subjective confidence level. Viewing unprocessed digital and unsharp-masked images in pairs resulted in approximately the same detectability as that obtained with the unsharp-masked images alone. However, this result may be influenced by the fact that the same limited viewing time was necessarily divided between the two images. 相似文献
54.
55.
腔隙性脑梗死的MRI与CT的诊断价值 总被引:1,自引:0,他引:1
目的:探讨腔隙性脑梗死的影像学特点及其临床意义,比较MRI和CT的诊断价值。方法:对120例经临床、MRI诊断明确为腔隙性脑梗死患者的病灶形态大小、部位、数量进行统计。结果:①120例行MRI检查患者共发现病灶890个,最多见于豆状核(占40.8%),其次为放射冠、丘脑、内囊、尾状核、桥脑,可为圆形、椭圆形、条索状病灶。②32例既做CT,又做MRI患者中,MRI检出的病灶数为CT的5.1倍,其中绝大多数CT漏检病灶直径≤5mm或位于幕下。结论:①腔隙性脑梗死常为多发,且第一次临床发病时多数患者颅内已存在无症状性腔隙性脑梗死病灶;②腔隙性脑梗死灶易为CT忽略,尤其是幕下病灶或≤5mm的病灶,这是造成既往文献报道腔隙性脑梗死好发部位差异较大的一个主要原因;③尽管腔隙性脑梗死病灶较小(≤10mm),但大部分(60.0%)急性期存在在周边水肿,需要相应的临床治疗。 相似文献
56.
Mao-Sheng Ran Meng-Ze Xiang Jie Li Jian Huang Eric Yu-Hai Chen Cecilia Lai-Wan Chan Yeates Conwell 《Archives of Suicide Research》2007,11(1):119-127
The aim of this study was to compare the demographic and clinical characteristics of individuals with affective disorders who had attempted suicide at some time in their lives and those who had not made a suicide attempt. In a Chinese rural community, individuals with suicide attempt (N = 30) and those without suicide attempt (N = 166) were assessed with Present State Examination (PSE). Attempters had a significantly higher level of family economic status, higher rate of lifetime depressed mood and hopelessness, and delusions than nonattempters. The logistic regression models also indicated that depressed mood and hopelessness were the most important predictors of suicide attempts. No significant difference in treatment condition was found between attempters and non-attempters. Early identification and interventions focusing on reducing depressed mood, hopelessness, and controlling psychotic symptoms may be helpful in reducing the risk of suicide attempts among individuals with affective disorders residing in the community. 相似文献
57.
58.
Klippel-Feil syndrome (KFS) is a heterogeneous entity, characterized by specific congenital anomalies of segmentation of the cervical spine. We report a case of KFS plus atretic meningocele in one identical twin and anencephaly in the other. These identical twins were both male with no chromosome defect. One of them had anencephaly diagnosed at the gestational age of 17 weeks and died soon after birth, whereas the co-twin had KFS with multiple congenital anomalies including short neck with low hairline, occipital atretic meningocele, butterfly vertebrae, hemivertebrae, cervico-thoracic scoliosis, left thumb preaxial polydactyly, and right undescended testis. He received rehabilitation during infancy and could walk at the age of 15 months. Both of these infants had preaxial polydactyly, which is an uncommon anomaly associated with KFS. In conclusion, iniencephaly and anencephaly are probably the extreme manifestations of KFS rather than different dysraphisms. Prompt clinical suspicion with early diagnostic imaging for spine lesions and occult opening of neural tube is mandatory for further intervention and rehabilitation. 相似文献
59.
60.
Many people die in emergency departments (EDs) across the United States from sudden illnesses or injuries, an exacerbation of a chronic disease, or a terminal illness. Frequently, patients and families come to the ED seeking lifesaving or life-prolonging treatment. In addition, the ED is a place of transition-patients usually are transferred to an inpatient unit, transferred to another hospital, or discharged home. Rarely are patients supposed to remain in the ED. Currently, there is an increasing amount of literature related to end-of-life care. However, these end-of-life care models are based on chronic disease trajectories and have difficulty accommodating sudden-death trajectories common in the ED. There is very little information about end-of-life care in the ED. This article explores ED culture and characteristics, and examines the applicability of current end-of-life care models. 相似文献