全文获取类型
收费全文 | 2631篇 |
免费 | 128篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 53篇 |
妇产科学 | 55篇 |
基础医学 | 367篇 |
口腔科学 | 41篇 |
临床医学 | 238篇 |
内科学 | 566篇 |
皮肤病学 | 19篇 |
神经病学 | 218篇 |
特种医学 | 97篇 |
外科学 | 381篇 |
综合类 | 13篇 |
一般理论 | 2篇 |
预防医学 | 223篇 |
眼科学 | 185篇 |
药学 | 150篇 |
肿瘤学 | 148篇 |
出版年
2023年 | 18篇 |
2022年 | 23篇 |
2021年 | 59篇 |
2020年 | 30篇 |
2019年 | 53篇 |
2018年 | 59篇 |
2017年 | 45篇 |
2016年 | 42篇 |
2015年 | 61篇 |
2014年 | 77篇 |
2013年 | 91篇 |
2012年 | 191篇 |
2011年 | 187篇 |
2010年 | 100篇 |
2009年 | 71篇 |
2008年 | 142篇 |
2007年 | 162篇 |
2006年 | 133篇 |
2005年 | 122篇 |
2004年 | 111篇 |
2003年 | 111篇 |
2002年 | 86篇 |
2001年 | 64篇 |
2000年 | 67篇 |
1999年 | 43篇 |
1998年 | 26篇 |
1997年 | 30篇 |
1996年 | 20篇 |
1995年 | 23篇 |
1994年 | 20篇 |
1993年 | 17篇 |
1992年 | 45篇 |
1991年 | 47篇 |
1990年 | 36篇 |
1989年 | 24篇 |
1988年 | 23篇 |
1987年 | 32篇 |
1986年 | 23篇 |
1985年 | 28篇 |
1984年 | 15篇 |
1983年 | 20篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1979年 | 26篇 |
1978年 | 15篇 |
1976年 | 15篇 |
1974年 | 19篇 |
1973年 | 12篇 |
1972年 | 10篇 |
1969年 | 10篇 |
排序方式: 共有2766条查询结果,搜索用时 15 毫秒
81.
Katrina Tatton‐Brown Anne Murray Sandra Hanks Jenny Douglas Ruth Armstrong Siddharth Banka Lynne M. Bird Carol L. Clericuzio Valerie Cormier‐Daire Tom Cushing Frances Flinter Marie‐Line Jacquemont Shelagh Joss Esther Kinning Sally Ann Lynch Alex Magee Vivienne McConnell Ana Medeira Keiichi Ozono Michael Patton Julia Rankin Debbie Shears Marleen Simon Miranda Splitt Volker Strenger Kyra Stuurman Clare Taylor Hannah Titheradge Lionel Van Maldergem I. Karen Temple Trevor Cole Sheila Seal Childhood Overgrowth Consortium Nazneen Rahman 《American journal of medical genetics. Part A》2013,161(12):2972-2980
82.
83.
Background: Destructive membranous periodontal disease, or ligneous gingivitis, is a rare condition involving nodular gingival enlargement with ulceration and periodontal tissue destruction. This review gives a brief account of the cases reported in the literature. An effort is also made to define the periodontal disease caused by plasminogen deficiency with a view to its potential inclusion in the classification of periodontal diseases. Methods: A MEDLINE/PubMed and manual search was conducted to find papers describing ≥1 case of ligneous disease involving the oral mucosa. Results: We identified 23 articles reporting 35 cases. For each patient, we analyzed various characteristics, including age, sex, age of onset, oral symptoms, histologic features, plasminogen levels (functional activity, plasma antigen), genetic features, treatment, and results of treatment during the reported follow‐up. Conclusions: Ligneous gingivitis is a rare periodontal disorder closely associated with ligneous conjunctivitis and plasminogen deficiency. Its diagnosis may be supported by the finding of genetic mutations responsible for the condition. Research is focusing on the future development of an effective therapy capable of arresting the destructive evolution of the disease. Additional studies, investigating features such as probing depth and attachment loss, are needed for the appropriate classification of this periodontal disease. 相似文献
84.
Thomas Riva Stefan Seiler Franziska Stucki Robert Greif Lorenz Theiler 《Paediatric anaesthesia》2016,26(12):1206-1208
In small children, high‐flow nasal cannula therapy may prolong apnea time even when an inspiratory oxygen fraction below 100% is used. This will be beneficial in prolonged intubation attempts, but especially during procedures requiring prolonged apnea time, leading to fewer airway manipulations and markedly enhanced surgical conditions. 相似文献
85.
Delbaere I Vansteelandt S De Bacquer D Verstraelen H Gerris J De Sutter P Temmerman M 《Human reproduction (Oxford, England)》2007,22(8):2080-2083
Birth weight is the single most important risk indicator for neonatal and infant mortality and morbidity, which has led to the idiom that 'every ounce counts'. Birth weight in turn, however, tends to vary widely across populations as a result of differential fetal growth velocity with such demographic factors as ethnicity, maternal and paternal height and altitude of residence. Accordingly, it has been acknowledged that the appraisal of birth weight should rely on its position relative to the birth weight distribution of the background population. This is commonly done by standardizing birth weight through its deviation from the population mean in the given gestational age stratum, as can be obtained from population-customized birth weight nomograms. This issue was recently revisited in 'Human Reproduction' through a plea for reporting birth weight as z-scores. In this article, we argue that adjustment for factors, such as gestational age, which may lie on the causal pathway from exposures present at the time of conception [e.g. single-embryo transfer (SET) versus double-embryo transfer (DET)] to birth weight, may induce bias, regardless of whether the adjustment happens via stratification, regression or through the use of z-scores. 相似文献
86.
87.
Breedveld S Storchi PR Keijzer M Heemink AW Heijmen BJ 《Physics in medicine and biology》2007,52(20):6339-6353
Treatment plan optimization is a multi-criteria process. Optimizing solely on one objective or on a sum of a priori weighted objectives may result in inferior treatment plans. Manually adjusting weights or constraints in a trial and error procedure is time consuming. In this paper we introduce a novel multi-criteria optimization approach to automatically optimize treatment constraints (dose-volume and maximum-dose). The algorithm tries to meet these constraints as well as possible, but in the case of conflicts it relaxes lower priority constraints so that higher priority constraints can be met. Afterwards, all constraints are tightened, starting with the highest priority constraints. Applied constraint priority lists can be used as class solutions for patients with similar tumour types. The presented algorithm does iteratively apply an underlying algorithm for beam profile optimization, based on a quadratic objective function with voxel-dependent importance factors. These voxel-dependent importance factors are automatically adjusted to reduce dose-volume and maximum-dose constraint violations. 相似文献
88.
89.
Peumans M De Munck J Van Landuyt K Lambrechts P Van Meerbeek B 《The journal of adhesive dentistry》2007,9(1):7-10
PURPOSE: The purpose of this prospective randomized controlled clinical study was to evaluate the clinical performance of a "mild" two-step self-etching adhesive, Clearfil SE, in Class V restorations after 5 years of clinical functioning. MATERIALS AND METHODS: Twenty-nine patients received two or four restorations following two randomly assigned experimental protocols: (1) a mild self-etching adhesive (Clearfil SE, Kuraray) was applied following manufacturer's instructions on both enamel and dentin (C-SE non-etch); (2) similar application of Clearfil SE, but including prior selective acid-etching of the enamel cavity margins with 40% phosphoric acid (C-SE etch). Clearfil AP-X (Kuraray) was used as the restorative composite for all 100 restorations. The clinical effectiveness was recorded in terms of retention, marginal integrity, marginal discoloration, caries recurrence, postoperative sensitivity, and preservation of tooth vitality after 5 years of clinical service. The hypothesis tested was that selective acid etching of enamel with phosphoric acid improved retention, marginal integrity, and clinical microleakage of Class V restorations. RESULTS: Only one restoration of the C-SE non-etch group was lost at the 5-year recall. All other restorations were clinically acceptable. Marginal integrity deteriorated with time in both groups. The number of restorations with defect-free margins was significantly lower in the C-SE non-etch group (p = 0.0043). This latter group presented significantly more small incisal marginal defects on the enamel side (p = 0.0169). Superficial marginal discoloration increased in both groups, but was more pronounced in the C-SE non-etch group and was related to the higher frequency of small incisal marginal defects. CONCLUSION: The clinical effectiveness of the two-step self-etching adhesive Clearfil SE remained excellent after 5 years of clinical service. Additional etching of the enamel cavity margins resulted in an improved marginal adaptation on the enamel side; however, this was not critical for the overall clinical performance of the restorations. 相似文献
90.
Nucleus HVC (formerly called high vocal center) of songbirds contains two types of projecting neurons connecting HVC respectively to the nucleus robustus archistriatalis, RA, or to area X. These two neuron classes exhibit multiple neurochemical differences and are differentially replaced by new neurons during adult life: high rates of neuronal replacement are observed in RA-projecting neurons only. The activity of these two types of neurons may also be modulated differentially by steroids. We analyzed by magnetic resonance imaging the effect of testosterone on the volume of RA and area X and on the dynamics of Mn(2+) accumulation in RA and area X of female starlings that had been injected with MnCl(2) through a permanent cannula implanted in HVC. Repeated visualization 6 weeks apart (before and after testosterone treatment) identified a volume increase of both nuclei in testosterone-treated birds associated with a concomitant decrease in controls. Following testosterone treatment, the total amount of Mn(2+) transported to RA and area X increased but the dynamics of accumulation, reflecting in part the activity of HVC neurons, was specifically altered in area X but not in RA. These data indicate that testosterone differentially affects the RA- and area X-projecting neurons in HVC. Manganese-enhanced magnetic resonance imaging (ME-MRI) thus provides repeated measures of connected brain areas and demonstrates testosterone-dependent regionally specific changes in brain activity and functional connectivity. The slow time scales investigated by this technique (compared to functional MRI) appear ideally suited for characterizing slow processes such as those involved in brain plasticity and learning. 相似文献