首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8727篇
  免费   673篇
  国内免费   96篇
耳鼻咽喉   76篇
儿科学   128篇
妇产科学   74篇
基础医学   406篇
口腔科学   151篇
临床医学   1315篇
内科学   880篇
皮肤病学   47篇
神经病学   271篇
特种医学   396篇
外科学   504篇
综合类   1340篇
预防医学   2573篇
眼科学   53篇
药学   799篇
  3篇
中国医学   302篇
肿瘤学   178篇
  2024年   7篇
  2023年   155篇
  2022年   275篇
  2021年   385篇
  2020年   341篇
  2019年   336篇
  2018年   340篇
  2017年   317篇
  2016年   253篇
  2015年   272篇
  2014年   673篇
  2013年   629篇
  2012年   595篇
  2011年   727篇
  2010年   582篇
  2009年   466篇
  2008年   496篇
  2007年   432篇
  2006年   365篇
  2005年   313篇
  2004年   235篇
  2003年   220篇
  2002年   158篇
  2001年   141篇
  2000年   96篇
  1999年   93篇
  1998年   75篇
  1997年   58篇
  1996年   53篇
  1995年   49篇
  1994年   35篇
  1993年   31篇
  1992年   26篇
  1991年   26篇
  1990年   18篇
  1989年   18篇
  1988年   14篇
  1987年   8篇
  1986年   6篇
  1985年   22篇
  1984年   15篇
  1983年   15篇
  1982年   13篇
  1981年   13篇
  1980年   16篇
  1979年   23篇
  1978年   19篇
  1977年   18篇
  1976年   7篇
  1975年   8篇
排序方式: 共有9496条查询结果,搜索用时 78 毫秒
1.
In this paper, a high-order moment-based multi-resolution Hermite weighted essentially non-oscillatory (HWENO) scheme is designed for hyperbolic conservation laws. The main idea of this scheme is derived from our previous work [J. Comput. Phys., 446 (2021) 110653], in which the integral averages of the function and its first order derivative are used to reconstruct both the function and its first order derivative values at the boundaries. However, in this paper, only the function values at the Gauss-Lobatto points in the one or two dimensional case need to be reconstructed by using the information of the zeroth and first order moments. In addition, an extra modification procedure is used to modify those first order moments in the troubled-cells, which leads to an improvement of stability and an enhancement of resolution near discontinuities. To obtain the same order of accuracy, the size of the stencil required by this moment-based multi-resolution HWENO scheme is still the same as the general HWENO scheme and is more compact than the general WENO scheme. Moreover, the linear weights are not unique and are independent of the node position, and the CFL number can still be 0.6 whether for the one or two dimensional case, which has to be 0.2 in the two dimensional case for other HWENO schemes. Extensive numerical examples are given to demonstrate the stability and resolution of such moment-based multi-resolution HWENO scheme.  相似文献   
2.
3.
PurposeTo investigate the reproducibility of diffusion-weighted (DW) MRI and 18F-Fluorodeoxyglucose (18F-FDG)-Positron emission tomography/CT (PET/CT) in monitoring response to neoadjuvant chemotherapy in epithelial ovarian cancer.Materials and methodsTen women (median age, 67 years; range: 41.8–77.3 years) with stage IIIC-IV epithelial ovarian cancers were included in this prospective trial (NCT02792959) between 2014 and 2016. All underwent initial laparoscopic staging, four cycles of carboplatine-paclitaxel-based chemotherapy and interval debulking surgery. PET/CT and DW-MRI were performed at baseline (C0), after one cycle (C1) and before surgery (C4). Two nuclear physicians and two radiologists assessed five anatomic sites for the presence of ≥ 1 lesion. Target lesions in each site were defined and their apparent diffusion coefficient (ADC), maximal standardized uptake value (SUV-max), SUV-mean, SUL-peak, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were monitored (i.e., 10 patients × 5 sites × 3 time-points). Their relative early and late changes were calculated. Intra/inter-observer reproducibilities of qualitative and quantitative analysis were estimated with Kappa and intra-class correlation coefficients (ICCs).ResultsFor both modalities, inter- and intra-observer agreement percentages were excellent for initial staging but declined later for DW-MRI, leading to lower Kappa values for inter- and intra-observer variability (0.949 and 1 at C0, vs. 0.633 and 0.643 at C4, respectively) while Kappa values remained > 0.8 for PET/CT. Inter- and intra-observer ICCs were > 0.75 for SUV-max, SUL-peak, SUV-mean and their change regardless the time-point. ADC showed lower ICCs (range: 0.013–0.811). ANOVA found significant influences of the evaluation time, the measurement used (ADC, SUV-max, SUV-mean, SUV-max, SUL-peak, MTV or TLG) and their interaction on ICC values (P = 0.0023, P< 0.0001 and P =0.0028, respectively).ConclusionWhile both modalities demonstrated high reproducibility at baseline, only SUV-max, SUL-peak, SUV-mean and their changes maintained high reproducibility during chemotherapy.  相似文献   
4.
培养“医信融合”复合型医学人才是医学高等教育在新时代信息技术发展背景下的历史使命。在引入“医信融合”教育理念的基础上,提出“医信融合”教育的人才培养目标及其内容体系,并据此构建了“医信融合”人才培养质量评价指标,提出了培养效果评价方法。介绍“医信融合”教育人才培养效果的评价方法,对山西医科大学“医信融合”教学效果进行实证分析,从而为“医信融合”教育实践提供借鉴。  相似文献   
5.
BackgroundThe growing enthusiasm for the use of reverse shoulder arthroplasty (RSA) in the treatment of primary glenohumeral osteoarthritis (GHOA) with an intact rotator cuff is based on data derived from single-center studies with limited generalizability and follow-up. This study compared patient-reported outcomes (PROs) between RSA and total shoulder arthroplasty (TSA) for the treatment of primary GHOA with up to 5-year follow-up and examined temporal trends in the treatment of GHOA between 2012 and 2021.MethodsA retrospective review was performed on patients with primary GHOA undergoing primary arthroplasty surgery from the Surgical Outcomes System global registry between 2012 and 2021. PROs including the American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation (SANE) score, and visual analog scale (VAS) for pain were compared between RSA and TSA at 1, 2, and 5 years postoperatively.ResultsA total of 4451 patients were included, with 2693 (60.5%) undergoing TSA and 1758 (39.5%) undergoing RSA. Both RSA and TSA provided clinically excellent outcomes at 1 year postoperatively (ASES: 80.8 ± 17.9 vs. 85.9 ± 15.2, respectively; SANE: 74.8 ± 24.7 vs. 79.5 ± 22.9; VAS pain: 1.3 ± 2.0 vs. 1.1 ± 1.7; all P < .05) that were maintained at 2 years (ASES: 81.3 ± 19.3 vs. 87.3 ± 14.9; SANE: 74.8 ± 26.2 vs. 79.7 ± 24.7; VAS pain: 1.3 ± 2.1 vs. 1.0 ± 1.6; all P < .05) and 5 years (ASES: 81.7 ± 16.5 vs. 86.9 ± 15.3; SANE: 71.6 ± 28.5 vs. 78.2 ± 25.9; VAS pain: 1.0 ± 1.7 vs. 1.0 ± 1.7; all P < .05), with statistical significance favoring TSA. After controlling for age and sex, there was an adjusted difference of 4.5 units in the ASES score favoring TSA (P = .005) at 5 years postoperatively but no differences in adjusted SANE (P = .745) and VAS pain (P = .332) scores. The use of RSA for GHOA grew considerably over time, from representing only 17% of all replacements performed for GHOA in 2012 to nearly half (47%) in 2021 (P < .001).ConclusionRSA as a treatment for GHOA with an intact rotator cuff seems to yield PROs that are largely clinically equivalent to TSA extending to 5 years postoperatively. The observed statistical significance favoring TSA appears to be of marginal clinical benefit based on established minimal clinically important differences and may be a result of the large sample size. Further research using more granular clinical data and examining differences in range of motion and complications is warranted as it may change the value analysis.  相似文献   
6.

Background

There were increased reports of fevers and febrile reactions in young children (particularly children aged <5?years) receiving the Seqirus/CSL Southern Hemisphere 2010 trivalent inactivated influenza vaccine (IIV3). Modifying the vaccine manufacturing process by increasing the minimum concentration of splitting agent (sodium taurodeoxycholate [TDOC]) from 0.5% w/v to 1.5% w/v for all strains resolved this issue. The current analysis compared fever rates in three pediatric studies of Seqirus IIV3 (S-IIV3) or quadrivalent inactivated influenza vaccine (S-IIV4), prepared using the modified manufacturing process, with fever rates in three pediatric studies of historical (pre-2010) IIV3 formulations. The historical IIV3 formulations, S-IIV3, and S-IIV4 had 0/3, 2/3, and 4/4 vaccine strains split at 1.5% TDOC, respectively.

Methods

For each study, fever rates (any grade and severe) were determined for the following age subgroups (as applicable), using the fever intensity grading system used in the S-IIV3/S-IIV4 studies: 6?months to <3?years; 3 to <5?years; 5 to <9?years; and 9 to <18?years.

Results

For each age subgroup, the any grade and severe fever rates were lower in the S-IIV3/S-IIV4 studies than in the historical IIV3 formulation studies, with the greatest differences in fever rates observed in the youngest age groups. In the 6?months to <3?years group, the any grade fever rate was 7.0% (severe fever: 2.5%) in one S-IIV4 study compared with 38.7% to 40.0% (severe fever: 9.6% to 17.8%) in the historical IIV3 formulation studies. In the 3 to <5?years subgroup, the any grade fever rate was 4.9% (severe fever: 1.2%) in one S-IIV4 study compared with 34.1% to 36.0% (severe fever: 6.3% to 16.5%) in the historical IIV3 formulation studies.

Conclusion

This analysis provides clinical evidence that the modified manufacturing process improved the fever profile across all pediatric age groups, in particular, in children aged <5?years.  相似文献   
7.

Purpose

This article presents a systematic review of the prevalence of violence against adolescents in the 22 countries of the Arab League.

Methods

Data on physical and emotional child maltreatment, sexual abuse, bullying and fighting, violence in schools, and intimate partner violence against adolescent girls were retrieved using: (1) a systematic search for peer-reviewed journal articles using Medline and the Social Sciences Citation Index; and (2) a search for nationally-representative, population-based surveys.

Results

Published evidence suggests that physical, sexual, and emotional violence against adolescents is widespread in the Arab region. In many studies, prevalence rates exceeded other regional or global estimates, including rates of violent discipline, fighting, and intimate partner violence against adolescent girls. Data on certain forms of violence (e.g. violent discipline) are available from many Arab countries; but data on other forms, e.g., sexual abuse, are scarce. Most peer-reviewed journal articles are based on small studies with diverse operational definitions and methods, making comparisons challenging.

Conclusions

High rates of violence against adolescents in the region merit greater attention from policy makers concerned with determinants of adolescent health. There is also a need to expand and improve the quality of quantitative and qualitative research on violence against adolescents in the region.  相似文献   
8.
9.
刘娟  齐艳  孙文霞 《现代预防医学》2020,(17):3117-3120
目的 对心衰患者所采用的综合营养评估工具及应用价值进行综述,为我国心衰患者的营养相关研究提供理论基础。方法 以“营养”、“心力衰竭”、“nutrition”、“heart failure”等为关键词,查询PubMed、Web of Science、知网等数据库相关文献,综述材料。结果 对心衰患者运用的综合营养评估工具种类较多,各量表信效度较高,营养风险和营养不良检出率较好,但均为普适量表,测评内容不能与心衰患者的临床特征完全相符,开发针对心衰患者的营养评估工具处于起步阶段。结论 综合营养评估工具对心衰患者的营养评估效果较好,未来需要加强针对心衰患者营养量表的研究。  相似文献   
10.
ObjectivesDementia is a progressive incurable life-limiting illness. Previous research suggests end-of-life care for people with dementia should have a symptomatic focus with an effort to avoid burdensome interventions that would not improve quality of life. This study aims to assess the appropriateness of end-of-life care in people who died with dementia in Belgium and to establish relative performance standards by measuring validated population-level quality indicators.DesignWe conducted a retrospective observational study.Setting and ParticipantsWe included all persons deceased with dementia in 2015 in Belgium. Data from 8 administratively collected population-level databases was linked.MeasuresWe used a validated set of 28 quality indicators for end-of-life dementia care. We compared quality indicator scores across 14 healthcare regions to establish relative benchmarks.ResultsIn Belgium in 2015, 10,629 people died with dementia. For indicators of appropriate end-of-life care, people who died with dementia had on average 1.83 contacts with their family physician in the last week before death, whereas 68.4% died at home or in their nursing home of residence. For indicators of inappropriate end-of-life care, 32.4% were admitted to the hospital and 36.3% underwent diagnostic testing in the last 30 days before death, whereas 25.1% died in the hospital. In the last 30 days, emergency department admission varied between 19% and 31%, dispensing of gastric protectors between 18% and 42%, and antihypertensives between 40% and 53% between healthcare regions, with at least 25% of health regions below 46%.Conclusions and ImplicationsOur study found indications of appropriate as well as inappropriate end-of-life care in people with dementia, including high rates of family physician contact, as well as high percentages of diagnostic testing, and emergency department and hospital admissions. We also found high risk-adjusted variation for multiple quality indicators, indicating opportunity for quality improvement in end-of-life dementia care.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号