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   8067篇
  免费   441篇
  国内免费   29篇
耳鼻咽喉   126篇
儿科学   370篇
妇产科学   47篇
基础医学   819篇
口腔科学   159篇
临床医学   628篇
内科学   1981篇
皮肤病学   109篇
神经病学   819篇
特种医学   250篇
外科学   1303篇
综合类   160篇
一般理论   1篇
预防医学   319篇
眼科学   278篇
药学   614篇
中国医学   16篇
肿瘤学   538篇
  2023年   89篇
  2022年   150篇
  2021年   324篇
  2020年   126篇
  2019年   221篇
  2018年   329篇
  2017年   200篇
  2016年   216篇
  2015年   220篇
  2014年   359篇
  2013年   480篇
  2012年   676篇
  2011年   690篇
  2010年   339篇
  2009年   299篇
  2008年   456篇
  2007年   507篇
  2006年   503篇
  2005年   413篇
  2004年   356篇
  2003年   317篇
  2002年   258篇
  2001年   126篇
  2000年   116篇
  1999年   94篇
  1998年   49篇
  1997年   44篇
  1996年   36篇
  1995年   28篇
  1994年   21篇
  1993年   33篇
  1992年   59篇
  1991年   58篇
  1990年   36篇
  1989年   30篇
  1988年   28篇
  1987年   35篇
  1986年   27篇
  1985年   26篇
  1984年   20篇
  1983年   18篇
  1982年   7篇
  1981年   10篇
  1980年   8篇
  1979年   7篇
  1978年   10篇
  1975年   10篇
  1973年   5篇
  1972年   5篇
  1967年   6篇
排序方式: 共有8537条查询结果,搜索用时 31 毫秒
191.
Elevated plasma levels of B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-pro-BNP) are seen in the setting of cardiac ischemia and are associated with adverse outcomes in patients with coronary artery disease. The mechanisms leading to natriuretic peptide elevation in patients with coronary artery disease, including the contribution of coronary atherosclerosis itself, have not been fully elucidated. Measurement of NT-pro-BNP, electron beam computed tomography, and cardiac magnetic resonance imaging were performed in 2,445 subjects from the Dallas Heart Study who were free of heart failure and renal insufficiency. Electron beam computed tomography-determined coronary artery calcium scores were categorized as none (<10), mild (> or =10 to <100), moderate (> or =100 to <400), and severe (> or =400). NT-pro-BNP levels increased significantly across increasing coronary artery calcium score categories (p <0.0001 for trend). In multivariate models adjusted for age, gender, race, body mass index, hypertension, history of myocardial infarction, angina, angiotensin-converting enzyme inhibitor use, beta-blocker use, left ventricular (LV) ejection fraction, and LV mass, higher coronary artery calcium scores remained independently associated with higher log NT-pro-BNP levels (p = 0.03). This association persisted in similar models excluding patients with low LV ejection fractions, LV hypertrophy, angina pectoris, and a history of myocardial infarction. In conclusion, these findings support the hypothesis that coronary atherosclerosis may directly influence the activation of the cardiac neurohormonal system.  相似文献   
192.
193.
ABSTRACT

In South Africa, high attrition rates throughout the care continuum present major barriers to controlling the HIV epidemic. Mobile health (mHealth) interventions may provide innovative opportunities for efficient healthcare delivery and improving retention in care. In this formative research, we interviewed 11 patients and 28 healthcare providers in North West Province, South Africa, to identify perceived benefits, concerns and suggestions for a future mHealth program to deliver HIV Viral Load and CD4 Count test results directly to patients via mobile phone. Thematic analysis found that reduced workload for providers, reduced wait times for patients, potential expanded uses and patient empowerment were the main perceived benefits of an mHealth program. Perceived concerns included privacy, disseminating distressing results through text messages and patients’ inability to interpret results. Participants felt that an mHealth program should complement face-to-face interactions and educational information to interpret results is needed. Providers identified logistical considerations and suggested protocols be developed. An mHealth program to deliver HIV test results directly to patients could mitigate multiple barriers to care but needs to be tested for efficacy. Concerns identified by patients and providers must be addressed in designing the program to successfully integrate with health facility workflow and ensure its sustainability.  相似文献   
194.
We conducted a field study of a rapid test (Brugia Rapid) for detection of Brugia malayi infection to validate its sensitivity and specificity under operational conditions. Seven districts in the state of Sarawak, Malaysia, which are endemic for brugian filariasis, were used to determine the test sensitivity. Determination of specificity was performed in another state in Malaysia (Bachok, Kelantan) which is non-endemic for filariasis but endemic for soil-transmitted helminths. In Sarawak both the rapid test and thick blood smear preparation were performed in the field. The rapid test was interpreted on site, whereas blood smears were taken to the district health centres for staining and microscopic examination. Sensitivity of Brugia Rapid dipstick as compared with microscopy of thick blood smears was 87% (20/23; 95% CI: 66.4-97.2) whereas the specificity was 100% (512/512). The lower sensitivity of the test in the field than in laboratory evaluations (> or =95%), was probably due to the small number of microfilaraemic individuals, in addition to difficulties in performing the test in remote villages by field personnel. The overall prevalence of brugian filariasis as determined by the dipstick is 9.4% (95% CI: 8.2-0.5) while that determined by microscopy is 0.90% (95% CI: 0.5-1.3) thus the dipstick detected about 10 times more cases than microscopy. Equal percentages of adults and children were found to be positive by the dipstick whereas microscopy showed that the number of infected children was seven times less than infected adults. The rapid dipstick test was useful as a diagnostic tool for mapping and certification phases of the lymphatic filariasis elimination programme in B. malayi-endemic areas.  相似文献   
195.
196.
BACKGROUND & OBJECTIVES: Malaria is the major health problem in western Rajasthan yet its vector fauna and transmission dynamics thereof is not understood properly. The present investigations report complete profile of qualitative and quantitative aspects of anopheline species occurring in different settings of desert ecosystem. METHODS: Area with irrigation through canal for more than 20 years (setting I), area with irrigation through canal for 10 years (setting II) and area without any irrigation (setting III) have been selected for studies. Species identification and their densities (per man hour) was made as per standard methods. RESULTS: In village of setting I, during rainy season, An. subpictus and An. stephensi were present while during winter season four species--An. subpictus, An. stephensi, An. culicifacies and An. annularis were collected. In all the villages of setting I, II and III no Anopheles mosquito was observed during summer season. In the villages of desert region without any irrigation facilities through any canal, the anopheline species were present only during rainy season. INTERPRETATION & CONCLUSION: An. stephensi is the major malaria vector of desert irrespective of whether the area is canal irrigated or not. During summer season absence of vector species in all the villages require further studies on micro-ecology of the species under desert conditions.  相似文献   
197.
Hepatitis C virus (HCV) genotype 4 (GT4) is genetically diverse, with 17 confirmed subtypes, and comprises approximately 13% of infections worldwide. In this study, we identified GT4 subtypes by phylogenetic analysis, assessed differences in patient demographics across GT4 subtypes, examined baseline sequence variability among subtypes and the potential impact on treatment outcome, and analyzed the development of viral resistance in patients who received a regimen of ombitasvir (nonstructural protein 5A [NS5A] inhibitor) plus ritonavir-boosted paritaprevir (NS3/4A inhibitor) with or without ribavirin (RBV) for the treatment of HCV GT4 infection. Phylogenetic analysis of HCV NS3/4A, NS5A, and NS5B nucleotide sequences identified 7 subtypes (4a, 4b, 4c, 4d, 4f, 4g/4k, and 4o) among 132 patient samples. Subtype prevalence varied by country, and the distributions of patient birth cohort and race were significantly different across GT4 subtypes 4a, 4d, and non-4a/4d. Baseline amino acid variability was detected in NS5A across GT4 subtypes but had no impact on treatment outcome. Three patients experienced virologic failure and were infected with subtype 4d, and the predominant resistance-associated variants at the time of failure were D168V in NS3 and L28V in NS5A. Overall, high response rates were observed among patients infected with 7 HCV GT4 subtypes, with no impact of baseline variants on treatment outcome. GT4 subtype distribution in this study differed based on patient demographics and geography.  相似文献   
198.
199.

Background and objective

Ankylosis of the temporomandibular joint is a clinical entity significant for a maxillofacial surgeon. Since time immemorial humanity is battling with this condition which is not just disfiguring the normal anatomy of the face but severely hampers the function of mastication. In this study we have tried to evaluate and correlate various factors leading to causation of ankylosis of TM Joint along with clinical manifestation and treatment planning as well as outcomes.

Study design

This is a retrospective study, records of 60 patients were selected out of which 28 patients reported for recall. Based on a predefined format, patients were evaluated and correlation was looked up on various accounts such as age of occurrence and age of reporting to the surgeon, probable etiology, sex distribution, treatment modality and postoperative outcome.

Results

The mean age of onset or occurrence was 4–7 years of age whereas age of reporting to the clinic was 16–17 years. Highest percentage of patients had trauma as an etiology (64 %) and the lowest percentage had congenital deformity (21 %). Three surgical techniques were evaluated and compared for their post surgical mouthopening, gap arthroplasty was done in 61 %, interpositional arthroplasty in 39 % and low ramus osteotomy in 21 %.

Conclusion

This study was aimed at analyzing the clinical form and function of the post surgical patient reviewing the recent radiographs to analyze the surgical site. The data collected was (1) Age of occurrence and age of reporting with the deformity (2) Etiological history (3) Sex and Side predisposition (4) Procedure used for correction of deformity (5) Recall (follow up) data especially recurrence and physiotherapy. We arrived at a conclusion that mean age of occurrence of deformity was approximately 4.7 years and age at which patient reported to clinic was 16.2 years. The main etiological factor was trauma (51 %) and ear infection (21 %). 57 % patients presented with unilateral deformity, with both the sides equally effected. The effectiveness of gap arthroplasty, interpositional arthroplasty and low ramus osteotomy procedures was evaluated. Gap arthroplasty and interpositional arthroplasty were found to be effective procedures. The importance of post operative physiotherapy was emphasised yet again through this study.  相似文献   
200.
Resistant hypertension, defined as inadequate blood pressure control despite three or more antihypertensive medications at maximally tolerated doses, is strongly linked to increased cardiovascular morbidity and mortality. Increased renal afferent and efferent sympathetic activity carried by nerves which arborize the adventitia of the renal arteries, appears to be central to the pathobiology of resistant hypertension. Historical experience indicates that surgical denervation and/or sympathectomy often dramatically reduced blood pressure in patients with malignant hypertension. Catheter-based radio-frequency renal denervation was developed in the past decade as a percutaneous adaptation of surgical denervation. Percutaneous renal denervation using a variety of systems has demonstrated to date, in non-randomized and unblinded studies, dramatic reductions in office-based blood pressure, but more modest impact on ambulatory blood pressure. The only single, appropriately powered, blinded, sham-controlled study of renal denervation conducted to date, however, failed to meet its primary endpoint, casting doubt on the value of the therapy. Ancillary benefits of renal denervation have been described in such conditions as diabetes mellitus, heart failure, and sleep apnea but require further study. While renal denervation is already widely available outside of the USA for commercial use, its utility in resistant hypertension must be vetted by further rigorous investigation before its use can be routinely recommended.  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