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   1644926篇
  免费   135168篇
  国内免费   2672篇
耳鼻咽喉   22035篇
儿科学   54680篇
妇产科学   47413篇
基础医学   233802篇
口腔科学   48108篇
临床医学   147076篇
内科学   323194篇
皮肤病学   34901篇
神经病学   134596篇
特种医学   65691篇
外国民族医学   474篇
外科学   247498篇
综合类   40089篇
现状与发展   3篇
一般理论   600篇
预防医学   128169篇
眼科学   37127篇
药学   123685篇
  35篇
中国医学   3021篇
肿瘤学   90569篇
  2018年   16161篇
  2016年   14090篇
  2015年   16289篇
  2014年   22255篇
  2013年   33723篇
  2012年   45775篇
  2011年   48089篇
  2010年   28175篇
  2009年   26940篇
  2008年   45719篇
  2007年   48000篇
  2006年   48800篇
  2005年   47271篇
  2004年   46605篇
  2003年   44484篇
  2002年   43377篇
  2001年   76018篇
  2000年   78567篇
  1999年   66668篇
  1998年   18190篇
  1997年   16675篇
  1996年   16623篇
  1995年   16326篇
  1994年   15314篇
  1993年   14453篇
  1992年   55597篇
  1991年   53927篇
  1990年   52689篇
  1989年   50939篇
  1988年   47329篇
  1987年   46643篇
  1986年   44371篇
  1985年   42932篇
  1984年   32122篇
  1983年   27654篇
  1982年   16256篇
  1981年   14545篇
  1980年   13647篇
  1979年   30520篇
  1978年   21123篇
  1977年   17808篇
  1976年   16736篇
  1975年   17605篇
  1974年   21511篇
  1973年   20697篇
  1972年   18882篇
  1971年   17796篇
  1970年   16306篇
  1969年   15282篇
  1968年   13960篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
ABSTRACT

Schnitzler syndrome is a rare, auto inflammatory condition known to manifest with bone pain, urticarial rash, fevers, relapsing arthralgia, and fatigue. In this case report, we describe a patient who was diagnosed with Schnitzler Syndrome that had initially presented with a unilateral pressure-type headache with a sensation of a ‘dagger’ stabbing into the back of the eye. He also had an associated ipsilateral redness of the conjunctiva, eyelid swelling, subtle optic disc elevations bilaterally and facial flushing - but with no visual acuity, pupillary, or lacrimatory changes. Anterior segment, fundoscopy, intraocular pressures and extraocular muscle movements were otherwise normal.  相似文献   
42.
Abstract

Introduction: Student-staff partnerships as a concept to improve medical education have received a growing amount of attention. Such partnerships are collaborations in which students and teachers seek to improve education by each adding their unique contribution to decision-making and implementation processes. Although previous research has demonstrated that students are favourable to this concept, teachers remain hesitant. The present study investigated teachers’ conceptions of student-staff partnerships and of the prerequisites that are necessary to render such partnerships successful and enhance educational quality.

Method: We conducted semi-structured interviews with 14 course coordinators who lead course design teams and also teach in 4 bachelor health programmes, using Bovill and Bulley’s levels of student participation as sensitising concepts during data analysis.

Results: The results pointed to three different conceptions of student-staff partnerships existing among teachers: Teachers teach and students study; teachers teach and value students’ feedback; and teachers and students co-create. The prerequisites for effective co-creation teachers identified were: Teachers must be open to involve students and create dialogues; students must be motivated and have good communication skills; the organisation must be supportive; and teachers should have the final say.

Conclusion: We conclude that teachers’ conceptions are consistent with Bovill and Bulley’s levels of student participation. Under certain conditions, teachers are willing to co-create and reach the highest levels of student participation.  相似文献   
43.
44.
ABSTRACT

Background

Post-stroke dysphagia is characterized by reduced corticolingual excitability and lingual pressure; however, it remains unknown if transcranial magnetic stimulation (TMS) directly facilitates lingual pressure generation.  相似文献   
45.
ABSTRACT

While research on sport-related concussion has increased dramatically over the past decade, research investigating concussion reporting is in its early stages. The purpose of this project was to assess concussion reporting and work with stakeholders to develop and assess strategies to improve reporting. We used a multi-site, repeated measures design with three NCAA Division I football programs, including 223 athlete participants. A modified community-based participatory research (CBPR) approach was used to develop intervention strategies (Fall 2017 season) with stakeholders designed to increase concussion reporting intentions. Preseason and postseason surveys were administered to determine effectiveness. Main outcome measures included concussion knowledge, intervention effectiveness, and reporting intention measures. For all three programs, concussion knowledge was unrelated to reporting intentions. Two of the three programs implemented the intervention strategies and for these programs there was evidence that the interventions were effective. Specifically, athletes from these two programs perceived more support from coaches about reporting (P< 0.05; t= 2.83), received education more frequently (P< 0.05; t= 2.67), and reported being more likely to report concussion symptoms (P< 0.05; t= 2.14). Our study demonstrates that working with stakeholders to develop site-specific strategies to improve concussion reporting is an effective approach to help improve reporting behaviours.  相似文献   
46.

Objectives

Triazole resistance in Aspergillus spp. is emerging and complicates prophylaxis and treatment of invasive aspergillosis (IA) worldwide. New polymerase chain reaction (PCR) tests on broncho-alveolar lavage (BAL) fluid allow for detection of triazole resistance at a genetic level, which has opened up new possibilities for targeted therapy. In the absence of clinical trials, a modelling study delivers estimates of the added value of resistance detection with PCR, and which empiric therapy would be optimal when local resistance rates are known.

Design

A decision-analytic modelling study was performed based on epidemiological data of IA, extended with estimated dynamics of resistance rates and treatment effectiveness. Six clinical strategies were compared that differ in use of PCR diagnostics (used vs not used) and in empiric therapeutic choice in case of unknown triazole susceptibility: voriconazole, liposomal amphotericin B (LAmB) or both. Outcome measures were proportion of correct treatment, survival and serious adverse events.

Results

Implementing aspergillus PCR tests was projected to result in residual treatment-susceptibility mismatches of <5% for a triazole resistance rate up to 20% (using voriconazole). Empiric LAmB outperformed voriconazole at resistance rates >5–20%, depending on PCR use and estimated survival benefits of voriconazole over LAmB. Combination therapy of voriconazole and LAmB performed best at all resistance rates, but the advantage over the other strategies should be weighed against the expected increased number of drug-related serious adverse events. The advantage of combination therapy over LAmB monotherapy became smaller at higher triazole resistance rates.

Conclusions

Introduction of current aspergillus PCR tests on BAL fluid is an effective way to increase the proportion of patients that receive targeted therapy for IA. The results indicate that close monitoring of background resistance rates and adverse drug events are important to attain the potential benefits of LAmB. The choice of strategy ultimately depends on the probability of triazole resistance, the availability of PCR and individual patient characteristics.  相似文献   
47.
Purpose: The purpose of the study is to report the prognostic factors and outcomes of vitrectomy (PPV) with silicone oil tamponade in rhegmatogenous retinal detachment (RRD) secondary to acute retinal necrosis (ARN).

Methods: This retrospective, non-randomized, interventional comparative study included 38 eyes of 38 patients. All cases underwent PPV with silicone oil tamponade. The main outcome measure was improvement of final visual acuity relative to the presenting visual acuity and factors affecting the same Group A included eyes with favorable vision of 20/400 or better and Group B included the others.

Results: Group A included 16 eyes (42.10%), group B included 22 eyes (57.89%). In Group A 2 eyes out of 16 (12.5%) and in Group B 12 eyes out of 22 (54.54%) had RRD at presentation (p = 0.02, 95% CI for the difference 7.88–65.78%). The time interval between first presentation and development of RRD in Group A was 30.94 ± 38.8 days (median 30 days) whereas that in Group B was 10.81 ± 11.73 days (median 8 days) (p = 0.02). The odds of visual improvement post-vitrectomy when RRD occurred later was 8.4 (p = 0.01, 95% CI 1.53–46.1). The usage of systemic steroids (odds 5.2, p = 0.03, 95% CI 1.14–23.54) and oral valacyclovir (odds 4.33, p = 0.04, 95% CI 1.05–17.84) were associated with odds favoring a good visual outcome. Recurrent RRD was noted in 3/16 eyes (18.75%) in Group A and 13/22 eyes (59.09%) in Group B (p = 0.03).

Conclusion: Delayed occurrence of RRD after ARN is a good prognostic factor. Usage of systemic steroids and oral valacylocvir are associated with a favorable visual outcome when started before the onset of RRD.  相似文献   

48.
Abstract

This is a secondary analysis of three qualitative studies about MAiD in which researchers asked about the differences between suicide and MAiD. In all, researchers interviewed 52 Canadians; 7 were people who had requested MAiD and had been found ineligible, 6 were MAiD providers and 39 were socially and economically marginalized. The overwhelming response was that MAiD is better than suicide in the context of suffering at the end of life. Whereas these people perceived suicide as uncertain, difficult, and something that was usually done alone and without support, they thought MAiD was certain, painless, and more socially acceptable.  相似文献   
49.
ObjectivesTo design and validate a feasible simulation to address an identified training gap in the management of intraoperative vitreous loss.MethodsOur simulation consists of a two-part non-toxic mixture that polymerises upon contact within a silicone training eye, to resemble the appearance of vitreous after staining with triamcinolone. This gel can be cut and aspirated with an anterior vitrectomy probe. Experienced consultant ophthalmic surgeons were invited to assess the simulation and anonymously complete validity questionnaires.ResultsSeven senior surgeons participated. Four (57%) strongly agreed and three (43%) agreed that the tissue behaved like vitreous. Six (86%) strongly agreed and one (14%) agreed that instrument handling was realistic. Three (43%) strongly agreed and four (57%) agreed that simulated triamcinolone staining was realistic. Four (57%) strongly agreed and three (43%) agreed that the simulation was visually convincing. Six (86%) strongly agreed and one (14%) agreed that this simulation is useful for training. No participants disagreed with any validity statements.ConclusionsThis novel simulation of anterior vitrectomy has good face and content validity, with unanimous agreement among experienced surgeons of its utility for training in the management of intraoperative vitreous loss.Subject terms: Education, Lens diseases  相似文献   
50.
During the ongoing public health crisis, many agencies are reporting COVID-19 health outcome information based on the overall population. This practice can lead to misleading results and underestimation of high risk areas. To gain a better understanding of spatial and temporal distribution of COVID-19 deaths; the long term care facility (LTCF) and household population (HP) deaths must be used. This approach allows us to better discern high risk areas and provides policy makers with reliable information for community engagement and mitigation strategies. By focusing on high-risk LTCFs and residential areas, protective measures can be implemented to minimize COVID-19 spread and subsequent mortality.  These areas should be a high priority target when COVID-19 vaccines become available

During the current public health crisis, many agencies and media outlets are reporting COVID-19 health outcome information based on the overall population of Cook County. As we have demonstrated, overall COVID-19 case counts and mortality can be misleading (details in >Story Map 1). Moreover, they offer little guidance for delivering public health interventions to high risk populations, a critical need during this second and potentially more devastating wave of the pandemic. The University of Illinois Chicago School of Public Health’s Public Health Geographic Information System Program (UIC-SPH-PHGIS) and Purdue research team has been examining spatial and temporal patterns of COVID-19 mortality with a focus on the significant loss of life from COVID-19 among Long-Term Care Facility (LTCF) residents in contrast to mortality in the community among residents of private households (non-LTCF; referred to as household population, HP). The goals of the study are:
  • Improve the accuracy of commonly quoted COVID-19 mortality indicators;
  • Gain a better understanding of spatial and temporal distribution of COVID-19 deaths;
  • Examine the role of race, ethnicity, and socioeconomic status in COVID-19 mortality;
  • Identify population and organizational parameters that can inform strategies for public health interventions.
Prioritizing the allocation of resources based on reliable information is a prerequisite of a successful mitigation strategy and immunization plan. Findings from our research have significant practical implications. The state and federal government face a series of policy decisions both due to the recent surge in positive cases and, when the time comes, the need to rationalize distribution of vaccines to high priority groups beyond healthcare workers and nursing home residents in critical areas. The research team seeks to modify prevailing practices in order to derive reliable information that guides policy decisions. At this stage of the study, we identified high-risk LTCFs and residential areas (HP) of Cook County from readily available, real-time mortality data.  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