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   755857篇
  免费   53990篇
  国内免费   19945篇
耳鼻咽喉   7951篇
儿科学   22921篇
妇产科学   11253篇
基础医学   62514篇
口腔科学   15434篇
临床医学   83530篇
内科学   128799篇
皮肤病学   10214篇
神经病学   52552篇
特种医学   25901篇
外国民族医学   60篇
外科学   84228篇
综合类   105142篇
现状与发展   64篇
一般理论   47篇
预防医学   69196篇
眼科学   11529篇
药学   67062篇
  639篇
中国医学   42474篇
肿瘤学   28282篇
  2023年   10899篇
  2022年   16602篇
  2021年   31152篇
  2020年   27712篇
  2019年   32293篇
  2018年   28976篇
  2017年   25542篇
  2016年   25434篇
  2015年   27373篇
  2014年   52159篇
  2013年   53325篇
  2012年   49023篇
  2011年   48483篇
  2010年   40711篇
  2009年   38483篇
  2008年   36800篇
  2007年   36903篇
  2006年   32283篇
  2005年   25432篇
  2004年   18865篇
  2003年   16384篇
  2002年   13315篇
  2001年   11628篇
  2000年   9790篇
  1999年   7913篇
  1998年   7152篇
  1997年   6449篇
  1996年   5567篇
  1995年   5747篇
  1994年   5446篇
  1993年   4381篇
  1992年   4505篇
  1991年   3951篇
  1990年   3524篇
  1989年   3216篇
  1988年   2969篇
  1987年   2622篇
  1986年   2318篇
  1985年   5974篇
  1984年   7043篇
  1983年   5037篇
  1982年   5580篇
  1981年   5248篇
  1980年   4602篇
  1979年   4136篇
  1978年   3416篇
  1977年   2783篇
  1976年   2928篇
  1975年   2142篇
  1974年   1939篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
101.
肥厚型心肌病(HCM)是一种常见的遗传性心脏病,是青少年及年轻运动员心源性猝死的最主要原因之一,其分子遗传学基础为基因突变。TNNC1是HCM的重要致病基因之一,目前仅发现其少量非同义单核苷酸多态性(nsSNPs)位点与HCM发病相关,但该基因其他nsSNPs数量较多,结合临床进行实验遗传检测其基因型与表型的关系,工作量巨大,尚不可行。因此,采用生物信息学方法,从dbSNP数据库中筛选出TNNC1基因全部的nsSNPs,联合4款(Mutation Taster、PolyPhen-2、PhD-SNP和MutPred)专业软件,进行有害性分级筛选和致病关联预测,最后进行突变蛋白三维结构建模及可视化分析。结果显示,首次从TNNC1基因102个nsSNPs位点中预测出疾病相关的18个(G159D、S69R、P52R、D149G、D3V、G140E、N51K、D151V、M47R、G110C、A23D、G140R、K158N、C35Y、R147C、L48P、F74C和V44G)高风险nsSNPs。基于生物信息学方法,以TNNC1基因的nsSNPs为示范,分析其nsSNPs与疾病表型的关系,这为其他遗传疾病致病基因nsSNPs的关联分析打下理论研究基础,具有重要的参考价值。  相似文献   
102.
ObjectivesThis review analyzes the experiences of patients and clinicians with regards to international cross-border reproductive care (CBRC) for the purpose of conception.MethodsElectronic databases PubMed, Embase, Web of Science, and Scopus were searched using ‘medical tourism’ AND ‘assisted reproductive technology’ from 1978 to 2020.ResultsPredominant patient motivators for CBRC were cost and legality of assisted reproduction technology (ART) in one's home country, followed by cultural factors like shared language, religion, and cultural familiarity. Clinicians suggested global laws for CBRC would reduce the potential for exploitation of vulnerable populations but believed the enactment of international regulations unlikely and, even if enacted, difficult to enforce.ConclusionsWhile patient and clinician experiences with CBRC varied, patients frequently cited financial and legal reasons for pursuing CBRC, while many providers had concern for the patient’s safety.Clinical practice implicationsThis review recommends clinicians involved in family planning counsel patients seeking treatment abroad by: (i) informing patients of the risks and benefits of treatment abroad, (ii) establishing guidelines and standards for clinicians on resuming patient care post-CBRC, and (iii) creating a directory of reputable CBRC clinicians and experts.  相似文献   
103.
104.
Circadian rhythms are 24-hour natural rhythms regulated by the suprachiasmatic nucleus, also known as the "master clock". The retino-hypothalamic tract entrains suprachiasmatic nucleus with photic information to synchronise endogenous circadian rhythms with the Earth’s light-dark cycle. However, despite the robustness of circadian rhythms, an unhealthy lifestyle and chronic photic disturbances cause circadian rhythm disruption in the suprachiasmatic nucleus’s TTFL loops via affecting glutamate and γ-aminobutyric acid-mediated neurotransmission in the suprachiasmatic nucleus. Recently, considerable evidence has been shown correlating CRd with the incidence of Alzheimer's disease. The present review aims to identify the existence and signalling of endocannabinoids in CRd induced Alzheimer's disease through retino-hypothalamic tract- suprachiasmatic nucleus-cortex. Immunohistochemistry has confirmed the expression of cannabinoid receptor 1 in the suprachiasmatic nucleus to modulate the circadian phases of the master clock. Literature also suggests that cannabinoids may alter activity of suprachiasmatic nucleus by influencing the activity of their major neurotransmitter γ-aminobutyric acid or by interacting indirectly with the suprachiasmatic nucleus’s two other major inputs i.e., the geniculo-hypothalamic tract-mediated release of neuropeptide Y and serotonergic inputs from the dorsal raphe nuclei. Besides, the expression of cannabinoid receptor 2 ameliorates cognitive deficits via reduction of tauopathy and microglial activation. In conclusion, endocannabinoids may be identified as a putative target for correcting CRd and decelerating Alzheimer’s disease.  相似文献   
105.
BackgroundRecent studies have described the use of telehealth for pediatric surgical care during the COVID-19 pandemic. We aimed to evaluate equity in telehealth use by comparing rates of utilization and satisfaction with pediatric surgical telemedicine among Hispanic patients.MethodsWe conducted a retrospective cohort study of patients seen by a surgical subspecialty provider in the outpatient setting at a quaternary pediatric hospital between April 1 and June 30, 2020. Patients evaluated in the same three-month period in 2019 were analyzed as a historic control. Differences in Family Experience Survey (FES) responses based on race and ethnicity and preferred language of care were assessed using univariable and multivariable generalized linear modeling.ResultsThe pandemic cohort included fewer patients of Hispanic ethnicity and fewer Spanish-speakers. After controlling for visit type, comparison of Spanish-speaking and English-speaking patients revealed that Spanish-speaking families had significantly lower scores for FES items that evaluated healthcare provider explaining (IRR 0.74, 95% CI: 0.61–0.90), listening (IRR 0.76, 95% CI: 0.63–0.92), and time spent with the family (IRR 0.73, 95% CI: 0.60–0.89). There were no differences in FES responses based on insurance status or degree of medical complexity.ConclusionsTelehealth services were less commonly used among Hispanic and Spanish-speaking patients. Language may differentially affect family satisfaction with healthcare and telehealth solutions. Strategies to mitigate these inequities are needed and may include strengthening interpreter services and providing language-concordant care.Level of evidenceLevel IV.  相似文献   
106.

Objective

To collaboratively implement the age-friendly health systems framework, known as the 4Ms: What Matters, Medication, Mentation, and Mobility, at The Primary Health Network (PHN), a federally qualified health center.

Data Sources

Data were collected from PHN electronic medical records (EMRs) for individuals over age 65 from December 30, 2019 to December 24, 2021 and from Project ECHO© attendance and evaluation surveys.

Study Design

The telementoring educational program, Project ECHO©, was used to engage PHN health care professionals working in rural areas of Pennsylvania to incorporate the 4Ms into their practice starting with the annual wellness visit (AWV). Project ECHO© was launched at three primary care sites. After 18 months, it was then disseminated to an additional 18 sites creating pilot and comparison groups. Outcomes included codesigned patient process metrics using EMR data and project ECHO© participant data.

Data Collection Methods

EMR data were generated by system reports created by PHN's quality assurance program manager. Project ECHO© data were collected and managed using REDCap electronic data capture tools. Outcomes were aggregated, analyzed for trends over time, and compared between groups.

Principal Findings

All nine process outcomes increased from baseline to follow-up at the three initial sites, ranging from 4% to 43% g. At year two, the three initial sites had higher rates on AWVs (pilot 24%, comparison 12%; p < 0.0001), Advance Care Planning (New on file, pilot 8%, comparison 2%; Discussed with patient, pilot 18%, comparison 13%; Patient declined, pilot 0%, comparison 0%; p = 0.0001), Dementia Screening (pilot 24%, comparison 12%; p < 0.0001), Fall Risk Management (pilot 43%, comparison 10%; p < 0.0001), and Mobility Goal (pilot 19%, comparison 9%; p < 0.0001); and lower rates on High-Risk Medication Elimination (pilot 54%, comparison, 63%, p < 0.02).

Conclusions

Access to high-quality geriatric care for rural older adults can be improved by increasing health care professionals' knowledge of the 4Ms, beginning with its incorporation into the AWV.  相似文献   
107.
Anthrax is a zoonotic infection caused by the gram-positive, aerobic, spore-forming bacterium Bacillus anthracis. Depending on the origin of the infection, serious health problems or mortality is possible. The virulence of B. anthracis is reliant on three pathogenic factors, which are secreted upon infection: protective antigen (PA), lethal factor (LF), and edema factor (EF). Systemic illness results from LF and EF entering cells through the formation of a complex with the heptameric form of PA, bound to the membrane of infected cells through its receptor. The currently available anthrax vaccines have multiple drawbacks, and recombinant PA is considered a promising second-generation vaccine candidate. However, the inherent chemical instability of PA through Asn deamidation at multiple sites prevents its use after long-term storage owing to loss of potency. Moreover, there is a distinct possibility of B. anthracis being used as a bioweapon; thus, the developed vaccine should remain efficacious and stable over the long-term. Second-generation anthrax vaccines with appropriate adjuvant formulations for enhanced immunogenicity and safety are desired. In this article, using protein engineering approaches, we have reviewed the stabilization of anthrax vaccine candidates that are currently licensed or under preclinical and clinical trials. We have also proposed a formulation to enhance recombinant PA vaccine potency via adjuvant formulation.  相似文献   
108.
IntroductionThe risk of mortality in patients with COVID-19 was found to be significantly higher in patients who experienced thromboembolic events. Thus, several guidelines recommend using prophylactic anticoagulants in all COVID-19 hospitalized patients. However, there is uncertainty about the appropriate dosing regimen and safety of anticoagulation in critically ill patients with COVID-19. Thus, this study aims to compare the effectiveness and safety of standard versus escalated dose pharmacological venous thromboembolism (VTE) prophylaxis in critically ill patients with COVID-19.MethodsA two-center retrospective cohort study including critically ill patients aged ≥ 18-years with confirmed COVID-19 admitted to the intensive care unit (ICU) at two tertiary hospitals in Saudi Arabia from March 1st, 2020, until January 31st, 2021. Patients who received either Enoxaparin 40 mg daily or Unfractionated heparin 5000 Units three times daily were grouped under the “standard dose VTE prophylaxis and patients who received higher than the standard dose but not as treatment dose were grouped under ”escalated VTE prophylaxis dose“. The primary outcome was the occurance of thrombotic events, and the secondary outcomes were bleeding, mortality, and other ICU-related complications.ResultsA total of 758 patients were screened; 565 patients were included in the study. We matched 352 patients using propensity score matching (1:1). In patients who received escalated dose pharmacological VTE prophylaxis, any case of thrombosis and VTE were similar between the two groups (OR 1.22;95 %CI 0.52–2.86; P = 0.64 and OR 0.75; 95% CI 0.16–3.38; P = 0.70 respectively). However, the odds of minor bleeding was higher in patients who received escalated VTE prophylaxis dose (OR 3.39; 95% CI 1.08–10.61; P = 0.04). There was no difference in the 30-day mortality nor in-hospital mortality between the two groups (HR 1.17;95 %CI0.79–1.73; P = 0.43 and HR 1.08;95 %CI 0.76–1.53; P = 0.83, respectively).ConclusionEscalated-dose pharmacological VTE prophylaxis in critically ill patients with COVID-19 was not associated with thrombosis, or mortality benefits but led to an increased risk of minor bleeding. This study supports previous evidence regarding the optimal dosing VTE pharmacological prophylaxis regimen for critically ill patients with COVID-19.  相似文献   
109.
目的 探讨主动脉夹层术后患者心理状况、躯体症状对其生活质量的影响及作用机制,为制订干预计划提供参考。方法 采用广泛性焦虑障碍量表、患者健康问卷抑郁量表、躯体症状量表、12项简明健康状况调查表对327例主动脉夹层术后患者进行调查,根据相关性分析结果提出假设,应用AMOS软件进行结构方程模型分析。结果 主动脉夹层术后患者生活质量得分(81.56±7.36)分,焦虑得分2.00(0, 3.00)分,抑郁得分2.00(0, 3.00)分,躯体症状得分5.00(2.00, 8.00)分;焦虑、抑郁、躯体症状对生活质量有直接影响,焦虑、抑郁通过躯体症状对生活质量有间接影响(均P<0.05)。结论 主动脉夹层术后患者生活质量处于中等偏上水平,应早期对主动脉夹层术后患者的心理状况与躯体症状进行动态评估与监测,及时进行心理干预和症状管理,以改善其生活质量。  相似文献   
110.
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