全文获取类型
收费全文 | 294286篇 |
免费 | 8906篇 |
国内免费 | 535篇 |
专业分类
耳鼻咽喉 | 2407篇 |
儿科学 | 10055篇 |
妇产科学 | 5015篇 |
基础医学 | 32433篇 |
口腔科学 | 3721篇 |
临床医学 | 24162篇 |
内科学 | 56050篇 |
皮肤病学 | 2124篇 |
神经病学 | 27896篇 |
特种医学 | 12533篇 |
外国民族医学 | 1篇 |
外科学 | 45862篇 |
综合类 | 3951篇 |
现状与发展 | 1篇 |
一般理论 | 156篇 |
预防医学 | 28373篇 |
眼科学 | 6021篇 |
药学 | 17910篇 |
1篇 | |
中国医学 | 901篇 |
肿瘤学 | 24154篇 |
出版年
2023年 | 609篇 |
2022年 | 1067篇 |
2021年 | 2369篇 |
2020年 | 1412篇 |
2019年 | 2412篇 |
2018年 | 24315篇 |
2017年 | 19096篇 |
2016年 | 21519篇 |
2015年 | 3605篇 |
2014年 | 4682篇 |
2013年 | 6238篇 |
2012年 | 15230篇 |
2011年 | 29589篇 |
2010年 | 23360篇 |
2009年 | 15891篇 |
2008年 | 27056篇 |
2007年 | 29674篇 |
2006年 | 8516篇 |
2005年 | 10166篇 |
2004年 | 10903篇 |
2003年 | 11255篇 |
2002年 | 9184篇 |
2001年 | 1442篇 |
2000年 | 1285篇 |
1999年 | 1377篇 |
1998年 | 1644篇 |
1997年 | 1414篇 |
1996年 | 1032篇 |
1995年 | 1040篇 |
1994年 | 888篇 |
1993年 | 843篇 |
1992年 | 703篇 |
1991年 | 689篇 |
1990年 | 658篇 |
1989年 | 573篇 |
1988年 | 551篇 |
1987年 | 521篇 |
1986年 | 439篇 |
1985年 | 527篇 |
1984年 | 579篇 |
1983年 | 543篇 |
1982年 | 721篇 |
1981年 | 611篇 |
1980年 | 573篇 |
1979年 | 370篇 |
1978年 | 356篇 |
1977年 | 351篇 |
1976年 | 300篇 |
1975年 | 277篇 |
1974年 | 298篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
Nils Beisemann Eric Mandelka Jan S. El Barbari Bjrn Kreher Sven Y. Vetter Paul Alfred Grützner Jochen Franke 《Journal of digital imaging》2022,35(3):514
Previous studies have demonstrated a frequent occurrence of screw/K-wire malpositioning during surgical fracture treatment under 2D fluoroscopy and a correspondingly high revision rate as a result of using intraoperative 3D imaging. In order to facilitate and accelerate the diagnosis of implant malpositioning in 3D data sets, this study investigates two versions of an implant detection software for mobile 3D C-arms in terms of their detection performance based on comparison with manual evaluation. The 3D data sets of patients who had received surgical fracture treatment at five anatomical regions were extracted from the research database. First, manual evaluation of the data sets was performed, and the number of implanted implants was assessed. For 25 data sets, the time required by four investigators to adjust each implant was monitored. Subsequently, the evaluation was performed using both software versions based on the following detection parameters: true-positive-rate, false-negative-rate, false-detection-rate and positive predictive value. Furthermore, the causes of false positive and false negative detected implants depending on the anatomical region were investigated. Two hundred fourteen data sets with overall 1767 implants were included. The detection parameters were significantly improved (p<.001) from version 1 to version 2 of the implant detection software. Automatic evaluation required an average of 4.1±0.4 s while manual evaluation was completed in 136.15±72.9 s (p<.001), with a statistically significant difference between experienced and inexperienced users (p=.005). In summary, version 2 of the implant detection software achieved significantly better results. The time saved by using the software could contribute to optimizing the intraoperative workflow. 相似文献
995.
996.
Four new 3-methyl-4-ethylideneproline-containing peptides, lucentamycins A-D (1-4), have been isolated from the fermentation broth of a marine-derived actinomycete identified by phylogenetic methods as Nocardiopsis lucentensis (strain CNR-712). The planar structures of the new compounds were assigned on the basis of 1D and 2D NMR spectroscopic techniques, while the absolute configurations of the amino acid residues were determined by application of the advanced Marfey method. Lucentamycins A (1) and B (2) showed significant in vitro cytotoxicity against HCT-116 human colon carcinoma. 相似文献
997.
Monika Maria Biernat Jolanta Rusiecka-Ziółkowska Elżbieta Piątkowska Iwona Helemejko Paweł Biernat Grażyna Gościniak 《Japanese journal of ophthalmology》2018,62(6):628-633
Purpose
Two Demodex species (eyelash mites)—D. folliculorum and D brevis—are believed to be associated with human skin and eye diseases. However, the clinical significance of infection with Demodex species remains controversial.Study design
The aim of this study was to estimate the prevalence of ocular demodicosis in patients with blepharitis as compared with the prevalence in the healthy population in Poland.Methods
This case-control prospective study was carried out from 2007 to 2016. The enrolled patients (668) were divided into 2 groups: the study group, comprising 553 patients with blepharitis (349 women and 204 men, aged 17–88 years), and the control group, comprising 115 healthy volunteers without a history of ocular pathologies (78 women and 37 men, aged 17–88 years). A sample of 10 eyelashes was taken aseptically from each eye of the examined person and later studied under a light microscope.Results
Demodex species were found in 62.4% (345/544) of the patients in the study group and in 24.3% (28/100) of the controls (P = .001, OR = 0.006). The overall prevalence was 55.8% (373/668) in all the examined participants. The presence of Demodex infection increased with age in both groups. No association of Demodex infection with gender was found (119/204 vs 226/349; P > .05, OR 1.086). A high mean number of mites was present more frequently in patients aged older than 50 years and in those who complained especially about itching (P < .05).Conclusion
The prevalence of ocular demodicosis is significantly correlated with blepharitis and increases with age.998.
Jie Jin Wang Gabriëlle H.S. Buitendijk Elena Rochtchina Kristine E. Lee Barbara E.K. Klein Cornelia M. van Duijn Victoria M. Flood Stacy M. Meuer John Attia Chelsea Myers Elizabeth G. Holliday Ava G. Tan Wayne T. Smith Sudha K. Iyengar Paulus T.V.M. de Jong Albert Hofman Johannes R. Vingerling Paul Mitchell Ronald Klein Caroline C.W. Klaver 《Ophthalmology》2014
999.
The distinction between penetrating eye injury with retained intraocular foreign body and perforating globe injuries is not always easy clinically. The case is presented of a 25-year-old man who sustained a perforating eye injury that was through a clear self-sealing corneal entry site and had no conjunctival or periorbital injury. He had periorbital ecchymosis on presentation suggesting that the globe had been perforated with resulting retro-orbital blood tracking to the periorbital region. This sign would not be expected had the foreign body remained intraocular. The management options of these cases are discussed. 相似文献
1000.
Ye Y Cheng X Luo HB Liu L Li YB Hou YP 《Journal of assisted reproduction and genetics》2008,25(8):389-394
Purpose The aim of the study was to evaluate the association of CYP1A1 and CYP1B1 polymorphisms with uterine leiomyoma in Chinese
women.
Methods We investigated 100 women with clinically diagnosed uterine leiomyoma and 110 healthy normal subjects from Chinese women.
The genetic distribution of two CYP1A1 polymorphisms at MspI, Ile462Val and four CYP1B1 polymorphisms at Arg48Gly, Ala119Ser,
Leu432Val, Asp449Asp were analyzed by polymerase chain reaction–restriction fragment length polymorphism and DNA sequencing
method.
Results All the SNPs showed polymorphisms in Chinese women. The genotype A/G and the allele G on Ile462Val was significantly different
between uterine leiomyoma patients and controls (P < 0.05).
Conclusion These results suggest that the genotype of CYP1A1 Ile462Val was associated with the increased risk of uterine leiomyomas in
Chinese women.
Capsule This is the first report that demonstrates the polymorphism at Ile462Val of CYP1A1 to be associated with uterine leiomyoma
in Chinese women. 相似文献