全文获取类型
收费全文 | 3497篇 |
免费 | 187篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 157篇 |
妇产科学 | 76篇 |
基础医学 | 509篇 |
口腔科学 | 74篇 |
临床医学 | 320篇 |
内科学 | 740篇 |
皮肤病学 | 192篇 |
神经病学 | 202篇 |
特种医学 | 95篇 |
外科学 | 429篇 |
综合类 | 14篇 |
预防医学 | 145篇 |
眼科学 | 77篇 |
药学 | 292篇 |
中国医学 | 8篇 |
肿瘤学 | 359篇 |
出版年
2024年 | 5篇 |
2023年 | 21篇 |
2022年 | 46篇 |
2021年 | 81篇 |
2020年 | 58篇 |
2019年 | 91篇 |
2018年 | 91篇 |
2017年 | 57篇 |
2016年 | 87篇 |
2015年 | 84篇 |
2014年 | 85篇 |
2013年 | 135篇 |
2012年 | 202篇 |
2011年 | 256篇 |
2010年 | 155篇 |
2009年 | 119篇 |
2008年 | 219篇 |
2007年 | 240篇 |
2006年 | 231篇 |
2005年 | 223篇 |
2004年 | 212篇 |
2003年 | 193篇 |
2002年 | 195篇 |
2001年 | 48篇 |
2000年 | 49篇 |
1999年 | 55篇 |
1998年 | 36篇 |
1997年 | 31篇 |
1996年 | 43篇 |
1995年 | 27篇 |
1994年 | 34篇 |
1993年 | 16篇 |
1992年 | 33篇 |
1991年 | 31篇 |
1990年 | 27篇 |
1989年 | 36篇 |
1988年 | 24篇 |
1987年 | 27篇 |
1986年 | 15篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1979年 | 7篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1975年 | 3篇 |
1972年 | 5篇 |
1970年 | 7篇 |
排序方式: 共有3706条查询结果,搜索用时 11 毫秒
81.
82.
Yasuko Ishimoto Taizo Wada Yoriko Kasahara Yumi Kimura Eriko Fukutomi Wenling Chen Mayumi Hirosaki Masahiro Nakatsuka Michiko Fujisawa Ryota Sakamoto Masayuki Ishine Kiyohito Okumiya Kuniaki Otsuka Kozo Matsubayashi 《Geriatrics & Gerontology International》2012,12(4):659-666
Aim: The 21‐item Fall Risk Index (FRI‐21) has been used to detect elderly persons at risk for falls. The aim of this longitudinal study was to evaluate the FRI‐21 as a predictor of decline in basic activities of daily living (BADL) among Japanese community‐dwelling elderly persons independent of fall risk. Methods: The study population consisted of 518 elderly participants aged 65 years and older who were BADL independent at baseline in Tosa, Japan. We examined risk factors for BADL decline from 2008 to 2009 by multiple logistic regression analysis on the FRI‐21 and other functional status measures in all participants. We carried out the same analysis in selected participants who had no experience of falls to remove the effect of falls. Results: A total of 45 of 518 participants showed decline in BADL within 1 year. Multivariate logistic regression analysis showed that age (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.05–1.20), FRI‐21 ≥ 10 (OR 3.81, 95% CI 1.49–9.27), intellectual activity dependence (OR 3.25, 95% CI 1.42–7.44) and history of osteoarthropathy (OR 3.17, 95% CI 1.40–7.21) were significant independent risk factors for BADL decline within 1 year. FRI‐21 ≥ 10 and intellectual activity dependence (≤3) remained significant predictors, even in selected non‐fallers. Conclusion: FRI‐21 ≥ 10 and intellectual activity dependence were significant predictive factors of BADL decline, regardless of fall experience, after adjustment for confounding variables. The FRI‐21 is a brief, useful tool not only for predicting falls, but also future decline in functional ability in community‐dwelling elderly persons. Geriatr Gerontol Int 2012; ??: ??–?? . 相似文献
83.
Luiz Fernando Gorup Bruno Perlatti Aleksey Kuznetsov Pedro Augusto de Paula Nascente Edison Perevalo Wendler Alcindo A. Dos Santos Willyam Rger Padilha Barros Thiago Sequinel Isabela de Macedo Tomitao Andressa Mayumi Kubo Elson Longo Emerson Rodrigues Camargo 《RSC advances》2020,10(11):6259
Metals capped with organochalcogenides have attracted considerable interest due to their practical applications, which include catalysis, sensing, and biosensing, due to their optical, magnetic, electrochemical, adhesive, lubrication, and antibacterial properties. There are numerous reports of metals capped with organothiol molecules; however, there are few studies on metals capped with organoselenium or organotellurium. Thus, there is a gap to be filled regarding the properties of organochalcogenide systems which can be improved by replacing sulfur with selenium or tellurium. In the last decade, there has been significant development in the synthesis of selenium and tellurium compounds; however, it is difficult to find commercial applications of these compounds because there are few studies showing the feasibility of their synthesis and their advantages compared to organothiol compounds. Stability against oxidation by molecular oxygen under ambient conditions is one of the properties which can be improved by choosing the correct organochalcogenide; this can confer important advantages for many more suitable applications. This paper reports the successful synthesis and characterization of gold nanoparticles functionalized with organochalcogenide molecules (dibutyl-disulfide, dibutyl-diselenide and dibutyl-ditelluride) and evaluates the oxidation stability of the organochalcogenides. Spherical gold nanoparticles with diameters of 24 nm were capped with organochalcogenides and were investigated using X-ray photoelectron spectroscopy (XPS) to show the improved stability of organoselenium compared with organothiol and organotellurium. The results suggest that the organoselenium is a promising candidate to replace organothiol because of its enhanced stability towards oxidation by molecular oxygen under ambient conditions and its slow oxidation rate. The observed difference in the oxidation processes, as discussed, is also in agreement with theoretical calculations.This study presents the improved stability against oxidation by molecular oxygen under ambient conditions of organoselenium compared with organothiol, and organotellurium. 相似文献
84.
Yuko Shima Koichi Nakanishi Taketsugu Hama Hironobu Mukaiyama Hiroko Togawa Mayumi Sako Hiroshi Kaito Kandai Nozu Ryojiro Tanaka Kazumoto Iijima Norishige Yoshikawa 《Pediatric nephrology (Berlin, Germany)》2013,28(1):71-76
Background
Some patients with IgA nephropathy (IgAN) achieve spontaneous remission even when not receiving medication. However, details on such remissions remain unknown. The aim of our study was to clarify this information in the clinical setting of childhood IgAN with minor glomerular abnormalities or focal mesangial proliferation (MGA/FMP).Methods
This study was a retrospective analysis of 96 children with MGA/FMP who did not receive medication from among the 555 patients with newly diagnosed childhood IgAN treated between January 1972 and December 2000. The Kaplan?CMeier method and Cox proportional hazard model were used for the analysis.Results
Of the 96 pediatric patients who did not receive medication, 57 (59.4?%) achieved spontaneous remission. The cumulative spontaneous remission rates among these patients were 57.5? and 77.4 % at 5?and 10 years, respectively, from onset. The mean time from onset to remission was 5.9?±?0.4?years. Clinical and histological findings were similar between the remission and non-remission groups. Of the 57 patients with spontaneous remissions, ten (17.5?%) also developed a recurrence of urinary abnormalities. The cumulative recurrence-free rates were 79.9?and 67.9 % at 5 and 10?years, respectively, after remission.Conclusions
The spontaneous remission rate in childhood IgAN with MGA/FMP was higher than expected. Our results suggest that physicians should consider the potential for spontaneous remission and refrain from very aggressive treatment in IgAN patients with MGA/FMP. 相似文献85.
86.
Bonifácio CC Shimaoka AM de Andrade AP Raggio DP van Amerongen WE de Carvalho RC 《Acta odontologica Scandinavica》2012,70(6):555-563
Abstract Background. The aim of this study is to critically evaluate the bond strength (BS) of Glass-Ionomer Cements (GIC) to dentine with microtensile (μTBS) and microshear (μSBS) BS tests by assessing their rankings and failure patterns. Methods. Samples were made on flat dentine surfaces and submitted to μTBS and μSBS. The materials used were: high viscosity GIC (Ketac(?) Molar Aplicap-KM), resin-modified GIC (Fuji II-FII), nano-filled resin-modified GIC (Ketac(?) N100-N100) and an etch-and-rinse adhesive system with a composite resin (Adper(?) Single Bond 2 and Z100(?)-Z100). All tests were performed with a Universal Testing Machine (24 h water storage, crosshead speed of 1 mm/min). Debonded surfaces were examined with a stereomicroscope (×40) to identify the failure mode. The data was analyzed with two-way ANOVA (p < 0.05) and LSD test. Results. Means were statistically different regarding the tests and materials, indicating that values for BS obtained for each material depend on the test performed. Failure analysis revealed that failures produced by μTBS were mainly cohesive for KM and FII. μSBS failures were mainly adhesive or mixed for all materials. For the μTBS, the rank was Z100 > FII > KM = N100, whereas for the μSBS it was Z100 = FII = KM > N100. Conclusion: It may be concluded that distinct micro-mechanical tests present different failure patterns and rankings depending on the material to be considered. 相似文献
87.
88.
Maiko Kusano Mayumi Yamanaka Kei Zaitsu Hiroshi Nakayama Jun’ichi Nakajima Takako Moriyasu Hitoshi Tsuchihashi Akira Ishii 《Forensic Toxicology》2016,34(2):304-315
Synthetic cannabinoids (SCs) are known to have structural or positional isomers. While regulations on synthetic drugs like synthetic cathinones and SCs have been placed worldwide for the ever-growing variety of new designer drugs, laws may not necessarily be applicable to their isomers. Toxicological differences may also exist among isomers for which most new designer drugs are still uninvestigated; thus, isomer differentiation becomes of forensic importance. The aim of this study was to differentiate the regioisomers of alkyl-substituted naphthoylindole-type SCs JWH-122 and JWH-210. Reference standards of the two drugs and their regioisomers were analyzed by gas chromatography–electron ionization-mass spectrometry (GC–EI-MS) first in full scan mode. Isomers that produced identical EI spectra were further analyzed by GC-tandem mass spectrometry (MS/MS) by selecting appropriate precursor ions. For JWH-210, comparison of the product ion spectra and the relative ion intensity ratios obtained from precursor ions at m/z 312 and 183 enabled differentiation between all seven regioisomers. Complete isomeric differentiation by MS/MS analysis was not attainable for JWH-122; however, combining chromatographic results with MS/MS analysis results enabled differentiation for all isomers. Two basic fragmentation pathways were speculated for both SCs; for JWH-210, fragmentation pathway tendencies differed among the isomers, resulting in their distinguishability. Our results demonstrated that the difference between the methyl (JWH-122) and ethyl (JWH-210) group substituents contributed to fragmentation pathway tendency differences and further distinguishability between the regioisomers. Functional group differences, especially their stereochemistries, were indicated to be critical factors in positional isomer differentiation by GC-MS/MS. 相似文献
89.
90.
Hiroshi Yamaguchi Kazuki Yamamoto Nobuyuki Akutsu Mayumi Kusumoto Shinsuke Kajihara Yoshimichi Yamaguchi Hiroki Takeda Atsushi Kawamura Yoshiyuki Uetani 《Pediatrics international》2016,58(7):622-624
The optimal timing of decompressive craniectomy in pediatric patients after presentation with malignant middle cerebral artery infarction is unknown. We report herein the case of a previously healthy 6‐year‐old Japanese girl who had good outcome after emergency decompressive craniectomy 116 h after malignant middle cerebral artery infarction. This case suggests that the timing of decompressive craniectomy can be delayed until deterioration of neurological findings and, compared with adults, a more prolonged time course for surgical intervention might be acceptable. 相似文献