全文获取类型
收费全文 | 5406篇 |
免费 | 499篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 114篇 |
儿科学 | 117篇 |
妇产科学 | 106篇 |
基础医学 | 672篇 |
口腔科学 | 90篇 |
临床医学 | 698篇 |
内科学 | 951篇 |
皮肤病学 | 88篇 |
神经病学 | 466篇 |
特种医学 | 238篇 |
外科学 | 886篇 |
综合类 | 86篇 |
现状与发展 | 20篇 |
一般理论 | 5篇 |
预防医学 | 566篇 |
眼科学 | 153篇 |
药学 | 296篇 |
中国医学 | 23篇 |
肿瘤学 | 354篇 |
出版年
2023年 | 88篇 |
2022年 | 104篇 |
2021年 | 272篇 |
2020年 | 122篇 |
2019年 | 192篇 |
2018年 | 224篇 |
2017年 | 177篇 |
2016年 | 145篇 |
2015年 | 177篇 |
2014年 | 246篇 |
2013年 | 295篇 |
2012年 | 361篇 |
2011年 | 349篇 |
2010年 | 189篇 |
2009年 | 193篇 |
2008年 | 224篇 |
2007年 | 212篇 |
2006年 | 215篇 |
2005年 | 156篇 |
2004年 | 161篇 |
2003年 | 144篇 |
2002年 | 148篇 |
2001年 | 77篇 |
2000年 | 68篇 |
1999年 | 66篇 |
1998年 | 53篇 |
1997年 | 54篇 |
1996年 | 64篇 |
1995年 | 49篇 |
1994年 | 36篇 |
1993年 | 35篇 |
1992年 | 50篇 |
1991年 | 50篇 |
1990年 | 60篇 |
1989年 | 73篇 |
1988年 | 55篇 |
1987年 | 62篇 |
1986年 | 54篇 |
1985年 | 53篇 |
1984年 | 36篇 |
1983年 | 37篇 |
1982年 | 29篇 |
1980年 | 30篇 |
1978年 | 35篇 |
1977年 | 31篇 |
1976年 | 25篇 |
1975年 | 36篇 |
1973年 | 25篇 |
1971年 | 25篇 |
1970年 | 25篇 |
排序方式: 共有5929条查询结果,搜索用时 15 毫秒
1.
Jae Eun Choi Tyler Werbel Zhenping Wang Chia Chi Wu Tony L. Yaksh Anna Di Nardo 《Journal of dermatological science》2019,93(1):58-64
Background
Rosacea is a chronic inflammatory skin condition whose etiology has been linked to mast cells and the antimicrobial peptide cathelicidin LL-37. Individuals with refractory disease have demonstrated clinical benefit with periodic injections of onabotulinum toxin, but the mechanism of action is unknown.Objectives
To investigate the molecular mechanism by which botulinum toxin improves rosacea lesions.Methods
Primary human and murine mast cells were pretreated with onabotulinum toxin A or B or control. Mast cell degranulation was evaluated by β-hexosaminidase activity. Expression of botulinum toxin receptor Sv2 was measured by qPCR. The presence of SNAP-25 and VAMP2 was established by immunofluorescence. In vivo rosacea model was established by intradermally injecting LL-37 with or without onabotulinum toxin A pretreatment. Mast cell degranulation was assessed in vivo by histologic counts. Rosacea biomarkers were analyzed by qPCR of mouse skin sections.Results
Onabotulinum toxin A and B inhibited compound 48/80-induced degranulation of both human and murine mast cells. Expression of Sv2 was established in mouse mast cells. Onabotulinum toxin A and B increased cleaved SNAP-25 and decreased VAMP2 staining in mast cells respectively. In mice, injection of onabotulinum toxin A significantly reduced LL-37-induced skin erythema, mast cell degranulation, and mRNA expression of rosacea biomarkers.Conclusions
These findings suggest that onabotulinum toxin reduces rosacea-associated skin inflammation by directly inhibiting mast cell degranulation. Periodic applications of onabotulinum toxin may be an effective therapy for refractory rosacea and deserves further study. 相似文献2.
Christopher N. Cooley Tyler J. Beranek Matthew A. Warpinski Robert Alexander Amanda O. Esquivel 《The American journal of emergency medicine》2019,37(2):199-203
Introduction
In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.Methods
We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.Results
A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.Conclusion
The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department. 相似文献3.
Paul Wexberg MD BM Richard Pacher MD Suzanne Rdler MD Katharina Kiss MD Gilbert Beran MD Michael Grimm MD Gerald Maurer MD Dietmar Glogar MD FESC 《The Journal of heart and lung transplantation》2002,21(12):583-1263
BACKGROUND: Endothelin, a peptide with strong vasoconstrictive and mitogenic properties, has been found to increase after cardiac transplantation. We therefore assessed the association between its precursor peptide, big endothelin-1, and intimal hyperplasia and coronary flow reserve after heart transplantation. METHODS: Thirty-five patients without hemodynamically significant coronary artery disease after heart transplantation were investigated: Average peak flow velocity in the left anterior descending artery (LAD) was assessed by intracoronary Doppler at baseline as well as after injection of adenosine; coronary flow reserve was calculated as a ratio of both and was corrected for patient age and baseline average peak flow velocity. Lumen, intima + media and total vessel area were measured by intracoronary ultrasound. The plasma concentration of big endothelin-1 in venous blood was determined by radioimmunoassay. RESULTS: Patients with elevated big endothelin-1 levels (>2 fmol/ml) tended to have a decreased corrected coronary flow reserve (2.60 +/- 0.9 vs 3.21 +/- 1.0, p = 0.078). They also had a significantly larger intima + media area (5.82 +/- 2.9 vs 2.37 +/- 2.9 mm(2), p = 0.004) and total vessel area (18.36 +/- 5.8 vs 12.81 +/- 4.8 mm(2), p = 0.012) than those with normal plasma concentrations. CONCLUSIONS: Our study suggests an association between elevated big endothelin-1 plasma levels and the development of intimal hyperplasia and reduction of coronary flow reserve after cardiac transplantation. 相似文献
4.
G Anita Heeren John B Jemmott Andrew Mandeya Joanne C Tyler 《AIDS education and prevention》2007,19(1):1-12
This study compared the predictive value of the theory of planned behavior in university students in South Africa (N = 251) and the United States (N = 160) who completed an anonymous self-administered questionnaire. Multiple regression analyses revealed that condom use and intention were significantly predicted by positive condom attitude, subjective norm, self-efficacy, and attending university in South Africa. Significant interactions between country and predictors indicated that subjective norm predicted condom use and intention more strongly in the American sample than in the South African sample; attitude predicted intention more strongly in the American sample than in the South African sample; but self-efficacy predicted intention more strongly in the South African sample than in the American sample. The theory of planned behavior may provide a useful framework for interventions to reduce South African students' risk of HIV/and sexuality transmitted diseases. Such interventions should especially focus on building self-efficacy to use condoms. 相似文献
5.
Davangere P Devanand Christian G Habeck Matthias H Tabert Nikolaos Scarmeas Gregory H Pelton James R Moeller Brett D Mensh Tyler Tarabula Ronald L Van Heertum Yaakov Stern 《Neuropsychopharmacology》2006,31(6):1327-1334
Temporoparietal and posterior cingulate metabolism deficits characterize patients with Alzheimer's disease (AD). A H(2)(15)O resting PET scan covariance pattern, derived by using multivariate techniques, was previously shown to discriminate 17 mild AD patients from 16 healthy controls. This AD covariance pattern revealed hypoperfusion in bilateral inferior parietal lobule and cingulate; and left middle frontal, inferior frontal, precentral, and supramarginal gyri. The AD pattern also revealed hyperperfusion in bilateral insula, lingual gyri, and cuneus; left fusiform and superior occipital gyri; and right parahippocampal gyrus and pulvinar. In an independent sample of 23 outpatients with mild cognitive impairment (MCI) followed at 6-month intervals, the AD pattern score was evaluated as a predictor of cognitive decline. In this MCI sample, an H2(15)O resting PET scan was carried out at baseline. Mean duration of follow-up was 48.8 (SD 15.5) months, during which time six of 23 MCI patients converted to AD. In generalized estimating equations (GEE) analyses, controlling for age, sex, education, and baseline neuropsychological scores, increased AD pattern score was associated with greater decline in each neuropsychological test score over time (Mini Mental State Exam, Selective Reminding Test delayed recall, Animal Naming, WAIS-R digit symbol; Ps<0.01-0.001). In summary, a resting PET covariance pattern previously reported to discriminate AD patients from control subjects was applied prospectively to an independent sample of MCI patients and found to predict cognitive decline. Independent replication in larger samples is needed before clinical application can be considered. 相似文献
6.
7.
8.
An open label randomized trial conducted in rural Kentucky compared the efficacy and safety of cefixime (CFX), 8 mg/kg once daily, with those of penicillin V (PEN), 250 mg 3 times daily, in 110 pediatric patients with Group A beta-hemolytic streptococcal pharyngitis. Forty-eight CFX and 47 PEN patients were evaluable for efficacy. At the end of therapy bacteriologic eradication was 45 of 48 (94%) and 36 of 47 (77%) in the CFX and PEN V groups, respectively (P < 0.05). Up to 6 weeks posttherapy 10 (21%) CFX patients and 21 (45%) PEN patients had positive Group A beta-hemolytic Streptococcus cultures (P < 0.05). Concordant serotypes were identified from 4 of 7 CFX and 15 of 17 PEN patients with positive repeat cultures. All discordant serotypes (5 of 31) were identified at greater than 19 days posttherapy. Symptomatic treatment failures (concordant serotypes) occurred in 1 (2%) CFX and 8 (17%) PEN patients (P < 0.05). Drug-related adverse experiences consisted of 2 cases of mild diarrhea and loose stools in the CFX group and none in the PEN group. No clinically significant laboratory test abnormalities occurred in either group. CFX, once daily, was as safe as and significantly more effective than PEN given 3 times daily for the treatment of Group A beta-hemolytic streptococcal pharyngitis. 相似文献
9.
Patients suffering from semantic dementia provide important constraints on theories of the structure and organisation of semantic memory. In this article we report one such patient, AM, whose progressive deterioration of semantics enables us to address the much-debated issue of whether conceptual structure is hierarchically organised. The hierarchical account predicts that brain damage should impair lower levels of the hierarchy (property information) before affecting higher level (category) information (Warrington and Shallice, Q. J. Exp. Psychol. 1975, 27, 635–657). We evaluate this prediction by repeated testing of AM in two studies—a semantic priming task and a verification task—over an 18 month period, contrasting the progressive deterioration of properties (functional and perceptual) and category relations (category co-ordinates and category labels). Properties were preserved longer than category information, arguing against a hierarchical account of semantic memory. In addition, functional properties were most robust to brain damage, supporting our claim that functional information plays a special role in semantic representations (Durrant-Peatfield et al., Proc. 19th Ann. Conf. of the Cognitive Science Society. Erlbaum, Mahwah, NJ, 1997, pp. 193–198. Tyler et al., Cognitive Neuropsychol. 1997, 14, 511–545). 相似文献
10.