全文获取类型
收费全文 | 72123篇 |
免费 | 6455篇 |
国内免费 | 1942篇 |
专业分类
耳鼻咽喉 | 745篇 |
儿科学 | 1633篇 |
妇产科学 | 1506篇 |
基础医学 | 8000篇 |
口腔科学 | 1292篇 |
临床医学 | 8203篇 |
内科学 | 12816篇 |
皮肤病学 | 1398篇 |
神经病学 | 4484篇 |
特种医学 | 2210篇 |
外国民族医学 | 2篇 |
外科学 | 8249篇 |
综合类 | 6892篇 |
现状与发展 | 17篇 |
一般理论 | 57篇 |
预防医学 | 5625篇 |
眼科学 | 2574篇 |
药学 | 6797篇 |
54篇 | |
中国医学 | 2748篇 |
肿瘤学 | 5218篇 |
出版年
2024年 | 199篇 |
2023年 | 784篇 |
2022年 | 1927篇 |
2021年 | 2785篇 |
2020年 | 2111篇 |
2019年 | 1958篇 |
2018年 | 2325篇 |
2017年 | 2085篇 |
2016年 | 2047篇 |
2015年 | 2650篇 |
2014年 | 3288篇 |
2013年 | 3728篇 |
2012年 | 5462篇 |
2011年 | 5649篇 |
2010年 | 3720篇 |
2009年 | 3210篇 |
2008年 | 4365篇 |
2007年 | 4252篇 |
2006年 | 4005篇 |
2005年 | 3750篇 |
2004年 | 3047篇 |
2003年 | 2828篇 |
2002年 | 2428篇 |
2001年 | 1510篇 |
2000年 | 1391篇 |
1999年 | 1131篇 |
1998年 | 608篇 |
1997年 | 451篇 |
1996年 | 378篇 |
1995年 | 316篇 |
1994年 | 315篇 |
1993年 | 272篇 |
1992年 | 551篇 |
1991年 | 538篇 |
1990年 | 496篇 |
1989年 | 451篇 |
1988年 | 398篇 |
1987年 | 414篇 |
1986年 | 381篇 |
1985年 | 323篇 |
1984年 | 261篇 |
1983年 | 206篇 |
1982年 | 163篇 |
1981年 | 131篇 |
1980年 | 127篇 |
1979年 | 161篇 |
1978年 | 121篇 |
1977年 | 103篇 |
1976年 | 85篇 |
1975年 | 91篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
21.
Eric Y. T. Chan Daniel K. Ng Chung-hong Chan Ka-li Kwok Pok-yu Chow Josephine M. Cheung Suk-yu Leung 《Sleep & breathing》2009,13(1):59-63
Background and objective The purpose of this study is to assess whether Chinese children with high apnea–hypopnea index (AHI) are sleepier by a modified Epworth Sleepiness Scale (ESS).
Materials and methods Records were retrospectively reviewed. We included children who were between 3 and 12 years old, admitted for overnight polysomnogram
because of suspected obstructive sleep apnea syndrome (OSAS). A modified ESS was used to assess excessive daytime sleepiness
(EDS) of the children.
Results One hundred ninety-two Chinese children were included. Children with high AHI, defined as AHI > 5.0, were sleepier than children with AHI less than or equal
to 5. After adjustment by age, gender, and obesity, children with high AHI remained significantly sleepier. Modified ESS was
significantly correlated with AHI (rho = 0.124, 95% CI = 0.004–0.281). Modified ESS score of >8 was the best cutoff point
with the sensitivity and specificity of 0.29 and 0.91, respectively. The odds ratio of children with modified ESS > 10 having
high AHI was 4.231 (95%CI = 1.248 to 14.338) and children with modified ESS > 8 had the highest odds ratio, 4.295(95%CI = 1.66
to 11.1), of having high AHI.
Conclusion
Chinese children with high AHI appear to be sleepier than children with low AHI. Children with suspected OSAS and high modified ESS,
i.e., ESS > 8, had significantly higher odds ratio of having high AHI. Increased sleepiness is a specific but not a sensitive
symptom in snoring children with high AHI. Screening for EDS in snoring children may help us identify those with high AHI
and prioritize the management of those children.
All authors worked and the study was carried out in Kwong Wah Hospital in Hong Kong. There was no conflict of interest and
no specific source of funding for the study. 相似文献
22.
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
23.
目的评价屈颈MRI对青年性上肢远端肌萎缩症的诊断价值。方法男性患者5例,平均年龄21岁,临床表现为一侧或两侧上肢远端肌萎缩。对照组为健康志愿者,21岁男性8例。2组均行常规及屈颈颈椎MR平扫,矢状、轴面SET1WI、T2WI、液体衰减反转恢复(FLAIR)序列扫描。结果常规颈椎扫描:5例患者下段颈髓变细;屈颈位MR扫描:下颈段颈6以下脊髓前屈、变扁平,矢状径4~6mm,硬膜囊后壁前移,硬膜后间隙明显增宽,可见多发条状、迂曲流空信号影及软组织信号。对照组:常规扫描,下颈段脊髓(颈6~胸2)可见颈膨大,屈颈位脊髓略变细(6~7mm),硬膜囊后壁无前移,硬膜后间隙未见扩张血管影。结论屈颈MRI有助于显示下颈段脊髓及硬膜囊改变,结合临床资料可准确诊断青年性上肢远端肌萎缩症。 相似文献
24.
Factors influencing family physicians to enter rural practice: Does rural or urban background make a difference? 下载免费PDF全文
25.
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
26.
Rapid growth in biomedical research coupled with dramatic advancement in biotechnology has significantly improved our understanding of the molecular basis involving cancer development and progression. This improvement has led to the discovery of new molecular markers for cancer diagnosis and prognosis as well as new molecular targets for cancer treatment and intervention. Continuous emergence of some new developing area in molecular profiling, new therapeutic agents, tissue microenvironment and systems biology have made significant progress in clinical oncology. Clinical research and investigation that focus on these new developments have begun to show exciting results that indicate future promises in improving patient management and survival. 相似文献
27.
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
28.
29.
30.
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