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   7519篇
  免费   571篇
  国内免费   21篇
耳鼻咽喉   127篇
儿科学   450篇
妇产科学   198篇
基础医学   1127篇
口腔科学   90篇
临床医学   539篇
内科学   1588篇
皮肤病学   227篇
神经病学   341篇
特种医学   103篇
外科学   729篇
综合类   335篇
一般理论   5篇
预防医学   529篇
眼科学   226篇
药学   715篇
中国医学   40篇
肿瘤学   742篇
  2023年   68篇
  2022年   56篇
  2021年   218篇
  2020年   158篇
  2019年   203篇
  2018年   233篇
  2017年   171篇
  2016年   220篇
  2015年   246篇
  2014年   330篇
  2013年   380篇
  2012年   543篇
  2011年   543篇
  2010年   308篇
  2009年   268篇
  2008年   375篇
  2007年   337篇
  2006年   285篇
  2005年   266篇
  2004年   239篇
  2003年   229篇
  2002年   205篇
  2001年   188篇
  2000年   175篇
  1999年   133篇
  1998年   53篇
  1997年   41篇
  1996年   40篇
  1995年   47篇
  1994年   48篇
  1993年   48篇
  1992年   103篇
  1991年   93篇
  1990年   91篇
  1989年   70篇
  1988年   77篇
  1987年   75篇
  1986年   65篇
  1985年   68篇
  1984年   40篇
  1983年   43篇
  1979年   54篇
  1978年   41篇
  1976年   40篇
  1975年   38篇
  1974年   45篇
  1973年   37篇
  1972年   52篇
  1971年   37篇
  1970年   37篇
排序方式: 共有8111条查询结果,搜索用时 15 毫秒
1.
The advent of precision medicine has changed the landscape of oncologic biomarkers, drug discovery, drug development, and, more importantly, outcomes for patients with cancer. Precision oncology entails the genomic profiling of tumors to detect actionable aberrations. The advances in clinical next-generation sequencing from both tumor tissue and liquid biopsy and availability of targeted therapies has rapidly entered mainstream clinical practice. In this review, recent major developments in precision oncology that have affected outcomes for patients with cancer are discussed. Rapid clinical development was seen of targeted agents across various mutational profiles such as KRASG12C (which was considered “undruggable” for almost 4 decades), Exon 20 insertions, and RET mutations. Approaches to precision chemotherapy delivery by the introduction of antibody drug conjugates in the armamentarium against lung cancer has been appreciated.  相似文献   
2.
Fast food and soft drinks consumption leading to excess calorie intake coupled with lack of acceptable physical activity has augmented the prevalence of overweight and obesity among the world population for the past few eras. A cross-sectional study was carried out among 475 youth selected by systematic random sampling attending in 27 established public and private universities and colleges of Bangladesh. The study was aimed to evaluate habitual facts associated with the prevalence of overweight and obesity among Bangladeshi youth. The rates of fast food consumption (once/week) are 50.6%, 43.7%, and 53.3% in overweight, pre-obese and obese-1 respondents accordingly and the rates of soft drinks consumption (4–6 times/week) are 40.5%, 59.2%, and 73.3% respectively for the same subjects. Moreover, approximately 40.8% of the youth went to fast food restaurants at least once per week and 27.2% went regularly (2 times/week). Youth having fast foods 2 times/week, consuming soft drinks 3–4 times/week were more likely to be obese. Besides, obesity epidemic was observed among those who have not the habit of doing physical exercise. This study provides evidence of increasing trend and threat to overweight and obesity for the Bangladeshi youth.  相似文献   
3.

Background

The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.

Objectives

The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.

Methods

PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.

Results

Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).

Conclusions

In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550)  相似文献   
4.

Background

In November 2017, the World Health Organization received initial reports of suspected diphtheria cases in camps established for displaced Rohingyas in Cox’s Bazar district, Bangladesh. By January 11, 2018, over 4,000 suspected cases of diphtheria and 30 deaths were reported. The Bangladesh government and partners implemented a diphtheria vaccination campaign in December 2017. Outbreak response staff reported anecdotal evidence of vaccine hesitancy. Our assessment aimed to understand vaccination barriers and opportunities to enhance vaccine demand among displaced Rohingyas in Bangladesh.

Methods

In January 2018, we conducted a qualitative assessment consisting of nine focus group discussions and 15 key informant interviews with displaced Rohingyas in three camps. Participants included mothers and fathers with under five-year-old children, community volunteers, majhis (camp leaders), Islamic religious leaders, traditional and spiritual healers, and teachers. We recruited participants using purposive sampling, and analyzed the data thematically.

Results

Across focus groups and in-depth interviews, trusted information sources cited by participants included religious leaders, elders, village doctors, pharmacists, majhis, and mothers trained by non-governmental organizations to educate caregivers. Treatment of diphtheria and measles was usually sought from multiple sources including traditional and spiritual healers, village doctors, pharmacies, and health clinics. Major barriers to vaccination included: various beliefs about vaccination causing people to become Christian; concerns about multiple vaccines being received on the same day; worries about vaccination side effects; and, lack of sensitivity to cultural gender norms at the vaccination sites.

Conclusion

Although vaccination was understood as an important intervention to prevent childhood diseases, participants reported numerous barriers to vaccination. Strengthening vaccine demand and acceptance among displaced Rohingyas can be enhanced by improving vaccination delivery practices and engaging trusted leaders to address religious and cultural barriers using community-based channels.  相似文献   
5.
Addition of authors’ affiliation to "Hepatitis B virus detected in paper currencies in a densely populated city of India: A plausible source of horizontal transmission?" World J Hepatol 2020 Oct 27; 12(10): 775-791. In this article, one of the affiliations of two authors was not mentioned. Ruchi Supekar, a joint first author and Subhajit Biswas, the corresponding author are affiliated to Academy of Scientific and Innovative Research (AcSIR) Ghaziabad- 201002, India.  相似文献   
6.

COVID-19 has become one of the significant sources of stress, fear, and anxiety throughout the world. Though the global effect on the psychological health of university settings is still unclear, the effect is highly significant (Lima et al., 2020). Therefore, assessing students’ anxiety regarding this pandemic is the need of the hour. The Fear of COVID-19 scale developed by Ahorsu et al. (2020) is a unidimensional scale with seven items that assess the intensity of fear of COVID-19. Given the rapid increase of COVID-19 cases and fear of uncertainty among college students in India, we aim to analyze the psychometric properties and validate this scale in the Indian context. A cross-sectional survey was conducted among college students (n= 572). In confirmatory factor analysis, the loadings ranged between .54 and .78. To further validate this, we have performed item response theory analysis. The unidimensional IRT estimates shown in Table 5 reveals that item difficulties ranged between ?.33 and 1.28. The item characteristics curve for the COVID-19 scale is given at the end of the results section.

  相似文献   
7.
ObjectiveDeep brain stimulation (DBS) surgery has its own set of risks and complications. This study from a single center and a single surgeon analyzes various risk factors for complications and tries to establish if there is a learning curve effect in minimizing the complications.Materials and MethodsA retrospective analysis of 519 patients (1024 leads) who underwent DBS surgery and 232 patients who underwent implantable pulse generator replacement (IPG), by a single surgeon, between the years 1999 and 2019 was performed. Perioperative and hardware related complications were evaluated.ResultsThe follow-up period ranged from six months to 20 years. Surgery-related complications occurred in 46 (8.9%) cases which included confusion in 31 (5.98%), intracerebral hemorrhage in 7 (1.3%), vasovagal attack in 3 (0.58%), respiratory distress in 2 (0.38%), postoperative aggressiveness in 1 (0.19%), and blepharospasm in 2 (0.38%) patients. Complications related to the DBS hardware were found in 35 cases, including erosion and infection in 22 (2.95%), inaccurate lead placement or migration in 6 (0.6%) lead fracture/extension wire failure in 2 (0.26%), IPG malfunction in 2 (0.26%), and hardware discomfort in 3 (0.4%) cases. In three patients, one lead was repositioned. In cases of infection, 87% of patients had either partial or complete removal of hardware. There was no mortality. The complications were analyzed for every 100 DBS procedures. There was a significant drop in the percentage of complications in from 23% in the first 100 cases to 7% in the last 100 cases (p < 0.0001).ConclusionConfusion remains the most frequent operative and perioperative complication. Erosion and infection of the surgical site represents the most frequent hardware complication. DBS surgery is safe and the complication rates are acceptably low. The complication rate also decreases with cumulative years of experience, demonstrating a learning curve effect.  相似文献   
8.
Aging leads to a gradual decline in the fidelity of cerebral blood flow (CBF) responses to neuronal activation, resulting in an increased risk for stroke and dementia. However, it is currently unknown when age-related cerebrovascular dysfunction starts or which vascular components and functions are first affected. The aim of this study was to examine the function of microcirculation throughout aging in mice. Microcirculation was challenged by inhalation of 5% and 10% CO2 or by forepaw stimulation in 6-week, 8-month, and 12-month-old FVB/N mice. The resulting dilation of pial vessels and increase in CBF was measured by intravital fluorescence microscopy and laser Doppler fluxmetry, respectively. Neurovascular coupling and astrocytic endfoot Ca2+ were measured in acute brain slices from 18-month-old mice. We did not reveal any changes in CBF after CO2 reactivity up to an age of 12 months. However, direct visualization of pial vessels by in vivo microscopy showed a significant, age-dependent loss of CO2 reactivity starting at 8 months of age. At the same age neurovascular coupling was also significantly affected. These results suggest that aging does not affect cerebral vessel function simultaneously, but starts in pial microvessels months before global changes in CBF are detectable.  相似文献   
9.
Aims of treatment for Crohn disease have moved beyond the resolution of clinical symptoms to objective end points including endoscopic and radiological normality. Regular re-evaluation of disease status to safely, readily and reliably detect the presence of inflammation and complications is paramount. Improvements in sonographic technology over recent years have facilitated a growing enthusiasm among radiologists and gastroenterologists in the use of ultrasound for the assessment of inflammatory bowel disease. Transabdominal intestinal ultrasound is accurate, affordable and safe for the assessment of lumi-nal inflammation and complications in Crohn disease, and can be performed with or without the use of intravenous contrast enhancement. Perianal fistulizing disease is a common, complex and often treatment-refractory complication of Crohn disease, which requires regular radiological monitoring. Endoanal ultrasound is invasive, uncomfortable and yields limited assessment of the perineal region. Although magnetic resonance imaging of the pelvis is established, timely access may be a problem. Transperineal ultrasound has been described in small studies, and is an accurate, painless and cost-effective method for documenting perianal fluid collections, fistulas and sinus tracts. In the present article, the authors review the literature regarding perineal ultrasound for the assessment of perianal Crohn disease and use case examples to illustrate its clinical utility.  相似文献   
10.
There is a relationship between arterial blood pressure, cardiac output and vascular resistance described mathematically, that helps us to understand short-term control of blood pressure in terms of a hydraulic system. Arterial baroreceptors are specialized sensors which mediate a rapid response to sudden changes in pressure through interaction with the autonomic nervous system. This in turn influences heart rate, inotropic state and vascular tone, altering distribution of blood between arterial and venous systems, thus compensating for acute changes in total blood volume. Total blood volume is controlled predominantly by the kidney, with the renin–angiotensin–aldosterone system acting as both the ‘sensor’ of blood pressure/volume (via renin release in the juxtaglomerular apparatus) and the ‘effector’ of blood pressure/volume (via aldosterone secretion by the adrenal cortex). Overall control is shared; the baroreceptors being responsible for mediating short-term changes, and renal mechanisms determining the long-term control of blood pressure. These systems have to be adaptable in order to deal with physiological variation in the delivery of blood to tissues from rest to exercise, and with the large shifts in blood volume seen in acute haemorrhage. Pathophysiological changes in these systems lead to maladaptive responses, with systemic hypertension the most commonly seen.  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