全文获取类型
收费全文 | 84814篇 |
免费 | 6007篇 |
国内免费 | 502篇 |
专业分类
耳鼻咽喉 | 1040篇 |
儿科学 | 2376篇 |
妇产科学 | 1807篇 |
基础医学 | 10403篇 |
口腔科学 | 1382篇 |
临床医学 | 8719篇 |
内科学 | 18191篇 |
皮肤病学 | 1690篇 |
神经病学 | 7015篇 |
特种医学 | 3156篇 |
外国民族医学 | 1篇 |
外科学 | 13511篇 |
综合类 | 1640篇 |
一般理论 | 80篇 |
预防医学 | 5069篇 |
眼科学 | 2379篇 |
药学 | 5726篇 |
中国医学 | 351篇 |
肿瘤学 | 6787篇 |
出版年
2023年 | 506篇 |
2022年 | 918篇 |
2021年 | 2023篇 |
2020年 | 1232篇 |
2019年 | 1860篇 |
2018年 | 2287篇 |
2017年 | 1707篇 |
2016年 | 1844篇 |
2015年 | 2208篇 |
2014年 | 3176篇 |
2013年 | 3933篇 |
2012年 | 6051篇 |
2011年 | 6307篇 |
2010年 | 3563篇 |
2009年 | 3069篇 |
2008年 | 5291篇 |
2007年 | 5531篇 |
2006年 | 5528篇 |
2005年 | 5367篇 |
2004年 | 5015篇 |
2003年 | 4660篇 |
2002年 | 4249篇 |
2001年 | 1496篇 |
2000年 | 1312篇 |
1999年 | 1300篇 |
1998年 | 919篇 |
1997年 | 716篇 |
1996年 | 588篇 |
1995年 | 539篇 |
1994年 | 513篇 |
1993年 | 455篇 |
1992年 | 661篇 |
1991年 | 635篇 |
1990年 | 593篇 |
1989年 | 554篇 |
1988年 | 507篇 |
1987年 | 510篇 |
1986年 | 458篇 |
1985年 | 414篇 |
1984年 | 384篇 |
1983年 | 326篇 |
1982年 | 296篇 |
1981年 | 261篇 |
1980年 | 213篇 |
1979年 | 221篇 |
1978年 | 166篇 |
1977年 | 141篇 |
1976年 | 119篇 |
1975年 | 107篇 |
1974年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
82.
83.
84.
85.
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
86.
Tooth movement and cytokines in gingival crevicular fluid and whole blood in growing and adult subjects. 总被引:1,自引:0,他引:1
Laura R Iwasaki Larry D Crouch Albert Tutor Scott Gibson Navin Hukmani David B Marx Jeffrey C Nickel 《American journal of orthodontics and dentofacial orthopedics》2005,128(4):483-491
INTRODUCTION: Tooth movement has been studied largely with respect to the force required for tipping when pressure distribution varies along the length of the periodontal ligament. But important factors for effective canine translation include the nature and magnitude of applied stress and the patient's cell biology. The purpose of this research was to test 3 hypotheses: (1) the velocity of tooth translation (v(t)) is related to applied stress and growth status, (2) a threshold of stress accounts for the lag phase, and (3) v(t) is correlated with the ratio (AI) of 2 cytokines (IL-1beta, IL-1RA) measured in gingival crevicular fluid (GCF) and stimulated whole blood (SWB). METHODS: Continuous maxillary canine retraction stresses of 13 kPa and 4, 26, or 52 kPa were applied bilaterally in 6 growing and 4 adult subjects for 84 days. Dental models and GCF samples were collected at 1- to 14-day intervals. Cytokines were measured in GCF and SWB cell cultures. RESULTS: V(t) was positively related to stress and was higher in growing subjects (P = .001). It was also related to AI(GCF) in growers (R2= 0.56) and nongrowers (R2= 0.72). Canines moved with 52 kPa showed a lag phase, and postlag phase AI(GCF) was twice that of lag phase AI(GCF). Mean v(t) and associated AI(GCF) during the postlag phase were nearly double the values for canines moved with 13 and 26 kPa. SWB production of cytokines was dose-dependent. For growing subjects, SWB IL-1RA was correlated with v(t) (R = 0.70-0.72), and AI(SWB) and IL-1beta concentrations were correlated with AI(GCF) (R = 0.73-0.78). CONCLUSIONS: V(t) varied with growth status and stresses < or = 52 kPa; stresses of < 52 kPa showed no lag phase; and equivalent stresses yielded subject-dependent differences in v(t), which correlated with cytokines in GCF and SWB. 相似文献
87.
Alexis A Gintowt Jeffrey J Germer P Shawn Mitchell Joseph D C Yao 《Journal of clinical virology》2005,34(2):155-157
BACKGROUND: The current manual sample processing method recommended for use with the TRUGENE HBV Genotyping Kit (TRUGENE HBV; Bayer HealthCare LLC, Tarrytown, NY) is labor-intensive and may be prone to specimen cross-contamination. Recent evaluations of the MagNA Pure LC (MP; Roche Applied Science, Indianapolis, IN) suggest that it is suitable for automated, contamination-free extraction and purification of viral nucleic acids from large-volume (1.0 mL) serum or plasma specimens. OBJECTIVES: We evaluated the MP Total Nucleic Acid Isolation Kit--Large Volume (Roche Applied Science) in conjunction with TRUGENE HBV to establish the analytical sensitivity (threshold titer) of the assay, in HBV DNA International Units (IU)/mL, for obtaining consistent, interpretable sequence data from TRUGENE HBV. STUDY DESIGN: HBV analytical standards, prepared as 10 replicates (1.0 mL each) at each of the following concentrations: 200, 1000, 5000, and 10,000 IU/mL, were processed by MP and analyzed by TRUGENE HBV according to manufacturer's instructions. Performance of TRUGENE HBV used in conjunction with MP sample processing was evaluated further using 22 clinical serum specimens containing low titers of HBV DNA. RESULTS: All replicates of HBV analytical standards at 1000, 5000, and 10,000 IU/mL yielded interpretable TRUGENE HBV sequences, whereas interpretable sequences were obtained in 90% (9 of 10) of the replicates at 200 IU/mL. TRUGENE HBV sequences were interpretable in 86% (19 of 22) of the clinical specimens studied. CONCLUSIONS: MP sample processing is efficient and suitable for use with TRUGENE HBV. When combined with MP sample processing, TRUGENE HBV yielded interpretable sequences from HBV analytical standards and clinical serum specimens with HBV DNA titers of > or =200 IU/mL. 相似文献
88.
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
89.
We report 2 cases of diffuse intraperitoneal metastases from testicular carcinoma following transabdominal retroperitoneal lymphadenectomy. This is an unusual pattern of metastasis for nonseminomatous germ cell tumors and it is believed to be the result of direct seeding from lymphatic leakage secondary to surgery. The value of computerized tomography in diagnosing this entity is emphasized. 相似文献
90.