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1.
目的通过有限元分析探讨直线通路微创开髓洞型对上颌第一前磨牙力学性能的影响。方法收集2018年6月至2020年6月于四川大学华西口腔医院口腔颌面外科就诊患者因正畸或牙周病拔除的上颌第一前磨牙,从中选取牙体完整、根尖孔发育完成的双根管牙20颗,对其显微CT(micro-CT)数据进行三维重建,在三维模型中模拟传统开髓洞型、桁架开髓洞型与直线通路微创开髓洞型的开髓与根管治疗(每组样本量均为20个)。建模完成后进行有限元分析,记录纵向及斜向负载模式下各组模型的牙颈部von Mises等效应力峰值(VM)并观测各组模型的应力分布模式。结果纵向负载模式下,3种开髓洞型牙颈部颊侧和腭侧VM分别为:桁架开髓洞型[(146.0±12.9)和(167.6±15.9)MPa],直线通路微创开髓洞型[(142.6±13.7)和(168.1±17.4)MPa],传统开髓洞型[(188.7±13.4)和(200.9±25.7)MPa]。与传统开髓洞型相比,桁架开髓洞型(t=9.01,P<0.001;t=4.59,P<0.001)和直线通路微创开髓洞型(t=9.64,P<0.001;t=3.76,P=0.004)均可有效降低根管治疗后上颌第一前磨牙颊侧和腭侧牙颈部VM,同时缓解应力在[牙合]面集中力加载区域、牙颈部及牙根的集中。在斜向负载模式下得到了相似的结果。在两种负载模式下,桁架开髓洞型与直线通路微创开髓洞型间颊腭侧牙颈部VM差异均无统计学意义(P>0.05)。结论直线通路微创开髓洞型可以有效保护根管治疗后上颌第一前磨牙的力学性能,具有一定的临床可行性。  相似文献   
2.
ObjectiveTo cross-culturally adapt and evaluate the psychometric properties of the University of Wisconsin Running Injury and Recovery Index questionnaire in Spanish (UWRI-S) in Chilean runners with a running-related injury.DesignCross-cultural adaptation and validation study, following the Consensus-based Standards for selecting health Measurement Instruments (COSMIN) recommendations.SettingOutpatient sports medicine clinic and running clubs.ParticipantsUWRI was forward and backward translated, and culturally adapted. Thirty-one runners participated in the content validity of the UWRI-S; and fifty-seven in the assessment of psychometric properties.Main outcome measuresRunners seeking care from a physiotherapist completed the UWRI-S (baseline and after 48–72 h for reliability), Lower Extremity Functional Scale (LEFS), Patient Specific Functional Scale (PSFS), Global Rating of Change scale (GROC), and Numeric Pain Rating Scale (NPRS).ResultsSuggestions about accuracy of wording and understanding of items were incorporated. UWRI-S showed a positive moderate correlation with LEFS (r = 0.6; p < 0.05), positive fair with GROC (r = 0.5, p < 0.05), negative fair with NPRS (r = −0.4; p < 0.05) and no correlation with PSFS (r = 0.3; p = 0.1). UWRI-S demonstrated acceptable internal consistency (α = 0.87) and test-retest reliability (ICC = 0.87).ConclusionUWRI-S is a valid and reliable measure to evaluate running ability of Chilean runners during recovery from a running-related injury.  相似文献   
3.
《Drug discovery today》2022,27(2):384-389
Proposals to waive intellectual property rights (IPRs) on coronavirus 2019 (COVID-19)-related developments have gained considerable support among politicians, including from US President Biden, academics, nongovernmental organizations (NGOs), the media, and the general public. However, there are surprisingly few reflections about the short- and long-term consequences for medical innovation, particularly the development of new drugs and vaccines. In this feature, I reflect on the consequences for innovative entrepreneurial companies, the incentives to innovate, and consequences for international knowledge flows to low- and middle-income countries. I conclude that waiving IPRs reduces opportunities for entrepreneurial companies to attract sufficient funding for developing medical innovations. Low- and middle-income countries might suffer reduced knowledge inflows in the absence of IPRs that undermine their ability to develop medical innovations.  相似文献   
4.
The Al-20Si-5Fe-3Cu-1Mg alloy was fabricated using selective laser melting (SLM). The microstructure and properties of the as-prepared SLM, post-treated SLM, and SLM with substrate plate heating are studied. The as-prepared SLM sample shows a non-uniform microstructure with four different phases: fcc-αAl, eutectic Al-Si, Al2MgSi, and δ-Al4FeSi2. With thermal treatment, the phases become coarser and the δ-Al4FeSi2 phase transforms partially to β-Al5FeSi. The sample produced with SLM substrate plate heating shows a relatively uniform microstructure without a distinct difference between hatch overlaps and track cores. Room temperature compression test results show that an as-prepared SLM sample reaches a maximum strength (862 MPa) compared to the heat-treated (524 MPa) and substrate plate heated samples (474 MPa) due to the presence of fine microstructure and the internal stresses. The reduction in strength of the sample produced with substrate plate heating is due to the coarsening of the microstructure, but the plastic deformation shows an improvement (20%). The present observations suggest that substrate plate heating can be effectively employed not only to minimize the internal stresses (by impacting the cooling rate of the process) but can also be used to modulate the mechanical properties in a controlled fashion.  相似文献   
5.
6.
注射用益气复脉(冻干)的质量标志物研究   总被引:10,自引:0,他引:10  
注射用益气复脉(冻干)是由红参、麦冬和五味子3味药材精制而成,临床上主要用于治疗冠心病劳累型心绞痛气阴两虚证及冠心病所致慢性左心功能不全II、III级气阴两虚证。根据质量标志物概念,从物质基础、药效、网络药理、药动学及药性等方面对注射用益气复脉(冻干)质量标志物进行预测分析,初步确定人参皂苷Rb1、Rg1、Rf、Rh1、Rc、Rb2、Ro、Rg3及麦冬皂苷C、麦冬苷元-3-O-α-L-吡喃鼠李糖基-(1→2)-β-D-吡喃葡萄糖苷、偏诺皂苷元-3-O-α-L-吡喃鼠李糖基-(1→2)-β-D-吡喃木糖基-(1→4)-β-D-吡喃葡萄糖苷、果糖、五味子醇甲13个成分为质量标志物,并以此为核心建立全程质量控制体系。基于质量标志物对注射用益气复脉(冻干)进行质控方法研究,可以为中药注射剂质量评价提供新的研究思路。  相似文献   
7.

Background/objectives

Pancreatic exocrine insufficiency (PEI) is commonly caused by chronic pancreatitis (CP) or cystic fibrosis (CF). There are no PEI-specific patient-reported assessments of symptoms and impacts. The PEI Questionnaire (PEI-Q) was developed through qualitative research with PEI patients and expert clinical input. This study evaluated the psychometric properties of the PEI-Q.

Methods

162 PEI patients (CF?=?71 and CP?=?91), 62 diarrhoea-specific irritable bowel syndrome (IBS-D) patients and 60 healthy controls completed the 26-item PEI-Q and the Gastrointestinal Quality of Life Index (GIQLI) at baseline. PEI patients completed the measures again two weeks later to assess the test-retest reliability of the PEI-Q. Analyses supported item reduction and scoring algorithm development, followed by psychometric evaluation.

Results

Over 90% of PEI patients completed at least 23 of the 26 items at baseline. Item responses and clinical relevance supported retention of 18 items. Factor analysis supported a three-factor solution (abdominal symptoms, bowel movements, impacts) with adequate model fit. PEI-Q scores had good internal consistency (Cronbach's alpha: 0.77–0.82) and test-retest reliability (ICC: 0.73–0.87). Correlations between PEI-Q and GIQLI supported convergent validity. Known-groups and receiver operating characteristic analyses demonstrated that PEI-Q scores discriminated (p?<?0.001) between differing PEI severities, and PEI patients and controls.

Conclusions

The PEI-Q has good validity and reliability. Results indicate that the PEI-Q could be used to aid identification and diagnosis of PEI, assist in the management of patients already diagnosed with PEI, ensuring correct and optimum treatment as well as enhance patient-clinician communication.  相似文献   
8.
9.
Background and aimsPublic health and clinic-based educational strategies are desperately needed to stem the tide of death from heart disease among people with diabetes in low and middle-income countries. This study translated the Heart Disease Fact Questionnaire into Persian and evaluated its reliability and validity for use in Iran.MethodsUsing rigorous translation methods, the 25-item scale was administered to Persian speakers with diabetes. The scale was evaluated for content validity, construct validity and reliability.ResultsParticipants were 268 patients with diabetes with mean age of 63.19 ± 16.61 years. The mean HDFQ score was 17.31 ± 5.11 (in the low range). Higher scores were associated with younger age, younger age of diabetes onset, higher education, higher employment position, family history of diabetes and hypertension, shorter diabetes duration, and adherence to home exercise regimens. Kuder–Richardson's reliability coefficient was good, i.e., 0.82. Confirmatory factor analysis showed that the factor loadings of all questions, except question number 25, were favorable, i.e., >0.3. Model fit indices were favorable: Chi-square statistic to degree of freedom ratio (χ2?df) = 1.82, Comparative fit index = 0.96, Tucker-Lewis Index = 0.96 and root mean square error = 0.06.ConclusionAfter removing item #25, the Persian heart disease fact questionnaire has good validity and reliability and can be used to inform and evaluate clinical and public health educational programs aimed at decreasing risk for heart disease among Persian speakers with diabetes.  相似文献   
10.
《Dental materials》2020,36(8):1038-1051
ObjectivesThis study aimed to investigate the collective influence of material properties and design parameters on the fracture behavior of monolithic dental crowns.MethodsThree-dimensional (3D) models (N = 90) with different combinations of design parameters (thickness, cusp angle and occlusal notch geometry) and material type (lithium disilicate, feldspar ceramic, zirconia, hybrid resin ceramic and hybrid polymer-infiltrated ceramic) were developed for the failure analysis using extended finite element method (XFEM) to identify the stress distribution, crack initiation load, fracture surface area and fracture pattern. Analytical formulation, in vitro fracture tests and fractographic analysis of dedicated models were also performed to validate the findings of the XFEM simulation.ResultsFor all material types considered, crowns with a sharp occlusal notch design had a significantly lower fracture resistance against occlusal loading. In most of the models, greater crown thickness and cusp angle resulted in a higher crack initiation load. However, the effect of cusp angle was dominant when the angle was in the low range of 50° for which increasing thickness did not enhance the crack initiation load.SignificanceComparing the critical load of crack initiation for different models with the maximum biting force revealed that for the studied monolithic materials excluding zirconia, a design with a rounded occlusal notch, 70° cusp angle and medium thickness (1.5 mm occlusal) is an optimum combination of design parameters in terms of tooth conservation and fracture resistance. Zirconia crowns exhibited sufficient strength for a more conservative design with less thickness (1.05 mm occlusal) and sharper cusp angle (60°).  相似文献   
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