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   1356篇
  免费   69篇
  国内免费   2篇
耳鼻咽喉   4篇
儿科学   55篇
妇产科学   32篇
基础医学   168篇
口腔科学   33篇
临床医学   116篇
内科学   199篇
皮肤病学   34篇
神经病学   140篇
特种医学   46篇
外国民族医学   1篇
外科学   154篇
综合类   57篇
一般理论   1篇
预防医学   173篇
眼科学   15篇
药学   84篇
中国医学   14篇
肿瘤学   101篇
  2024年   3篇
  2023年   22篇
  2022年   58篇
  2021年   81篇
  2020年   52篇
  2019年   49篇
  2018年   66篇
  2017年   45篇
  2016年   32篇
  2015年   44篇
  2014年   57篇
  2013年   69篇
  2012年   100篇
  2011年   115篇
  2010年   56篇
  2009年   52篇
  2008年   68篇
  2007年   77篇
  2006年   66篇
  2005年   49篇
  2004年   36篇
  2003年   25篇
  2002年   32篇
  2001年   14篇
  2000年   7篇
  1999年   6篇
  1998年   8篇
  1996年   4篇
  1995年   4篇
  1992年   7篇
  1991年   8篇
  1990年   13篇
  1989年   5篇
  1988年   3篇
  1987年   5篇
  1986年   3篇
  1985年   5篇
  1984年   3篇
  1982年   3篇
  1979年   5篇
  1977年   7篇
  1974年   13篇
  1973年   4篇
  1972年   8篇
  1971年   8篇
  1970年   4篇
  1969年   4篇
  1967年   4篇
  1966年   2篇
  1965年   2篇
排序方式: 共有1427条查询结果,搜索用时 15 毫秒
31.
32.
Hereditary Spastic Paraplegias (HSP) encompass a clinically and genetically heterogeneous group of neurodegenerative disorders characterized by insidiously progressive weakness and spasticity of the lower extremities. We describe a consanguineous Saudi family segregating a complicated form of HSP in an autosomal recessive pattern. The two affected siblings had early onset, cognitive, speech and motor involvement with spasticity of the lower extremities. Their upper extremities were mildly hypertonic. An intronic splice acceptor site mutation in ERLIN2 was found to be responsible for causing this disorder found in this family. ERLIN2 is a mediator of endoplasmic reticulum degradation pathway (ERAD) which helps to remove the aberrant proteins. Our results, in concurrence with previous studies suggest that alteration in ERLIN2 is one of the causes of complicated HSP, thereby increasing the spectrum of known mutations in SPG18.  相似文献   
33.
34.

Background

Nutrition support has undergone significant advances in recent decades, revolutionizing the care of critically ill and injured patients. However, providing adequate and optimal nutrition therapy for such patients is very challenging: it requires careful attention and an understanding of the biology of the individual patient’s disease or injury process, including insight into the consequent changes in nutrients needed.

Objective

The objective of this article is to review the current principles and practices of providing nutrition therapy for critically ill and injured patients.

Methods

Review of the literature and evidence-based guidelines.

Results

The evidence demonstrates the need to understand the biology of nutrition therapy for critically ill and injured patients, tailored to their individual disease or injury, age, and comorbidities.

Conclusion

Nutrition therapy for critically ill and injured patients has become an important part of their overall care. No longer should we consider nutrition for critically ill and injured patients just as “support” but, rather, as “therapy”, because it is, indeed, a key therapeutic modality.  相似文献   
35.
Silver nanoparticles (SNP) are used in many pharmaceutical, cosmetic, and industrial products already available in the market. Although they are considered relatively safe, many toxic and pathological alterations in different organs including immune organs were reported after SNP administration. In this study, 10-week-old male mice (n = 20) were divided into two groups. Ten mice received greenly synthesized gelatin-coated silver nanoparticles in a dose of 10 mg/kg body weight for five consecutive days while the other 10 received 0.5 ml of distilled water daily for 5 days and kept as control. At the sixth day, all mice were sacrificed; blood and tissue samples were collected and prepared for pathological analysis. Liver and kidney lesions were in the form of degenerative and inflammatory changes. Interestingly, the immune organs were drastically affected by SNP treatment. Severe hyperplasia of the Peyer’s patches was noticed in the intestines of intoxicated animals both in gross and microscopic examination. Spleen was enlarged and showed large number of megakaryocytes. The particles were encountered in membrane-bound phagosomes inside macrophages in different organs like lungs and spleen. Blood picture complied to morphological findings with an increase in monocytes and eosinophils accompanied by drop in the platelets count in the intoxicated animals.  相似文献   
36.
Physical functioning status is often assessed using scales of activities of daily living and instrumental activities of daily living. Different ways of defining change in adequacy of performance of both activities of daily living and instrumental activities of daily living tasks may be used, including increasing difficulty in performance, the need for assistance and inability to do tasks. In this prospective study, we investigated the effect of different definitions of decline on estimates of physical function, and explored the relationships between decline in each activity of daily living individually and potential predictors. The study was based on a sample of 999 individuals aged 65 years or more who participated in a national survey of quality of life, of whom 531 (68% of those eligible for follow up) responded 12-18 months later. Different definitions of decline were used and the prevalence of decline was, depending on the individual activities of daily living item, used as an outcome in logistic regression models. The results showed that the strength of association with chronic diseases, demographic, psychological and environmental factors varied by altering the activities of daily living item used. Decline in ability to walk 400 yards was strongly associated with respiratory problems (odds ratio 3.5 [95% confidence interval 1.3-9.0]) while decline in ability to get on a bus was associated with musculoskeletal problems (odds ratio 2.8 [95% confidence interval 1.4-5.6]). In conclusion, the prevalence of decline varies by definition, and summary measures which are customarily used to describe disability, may be inadequate for the assessment and identification of predictors of decline in functional ability.  相似文献   
37.

Background

Patients with ductal carcinoma-in-situ (DCIS) are currently not prescribed adjuvant systemic treatment after surgery and radiotherapy. Prediction of DCIS patients who would benefit from radiotherapy is warranted. Statins have been suggested to exert radio-sensitizing effects. The target for cholesterol-lowering statins is HMG-CoA reductase (HMGCR), the rate-limiting enzyme in the mevalonate pathway. The aim of this study was to examine HMGCR expression in DCIS and study its treatment predictive value.

Methods

A population-based cohort including 458 women diagnosed with primary DCIS between 1986 and 2004 were followed until November 2011 to study long-term survival. Tumor tissue microarrays were constructed, and immunohistochemical analyses were performed to detect cytoplasmic protein expression of HMGCR. The association between DCIS HMGCR expression and invasive breast cancer recurrence-free survival (RFSinv) and overall survival (OS) was analyzed by Kaplan–Meier curves, log rank test, and Cox proportional hazard analysis.

Results

HMGCR was strongly expressed in 24 % of the assessed DCIS samples, moderately expressed in 46 %, and weakly expressed in 23 %; no expression was detected in 7 % of the samples. During the follow-up time (median 13.8 years), 61 patients were diagnosed with an invasive breast cancer recurrence, and 80 patients died. A crude analysis showed no survival benefit from radiotherapy. However, patients with strong HMGCR expression showed an improved RFSinv (log rank, p = 0.03) and OS (log rank, p = 0.04) after radiotherapy. No statistically significant interaction was observed for HMGCR and radiotherapy (RFSinv p = 0.69 and OS p = 0.29).

Conclusions

This study demonstrates HMGCR expression in DCIS and suggests HMGCR as a predictive marker of response to postoperative radiotherapy in DCIS, although the test for interaction was nonsignificant. Future DCIS studies addressing the potential of statin treatment targeting HMGCR are warranted.  相似文献   
38.
39.
We conducted a seroprevalence survey among 500 healthy adult donors at Zanzibar National Blood Transfusion Services. Dengue virus IgG seroprevalence was 50.6% and independently associated with age and urban residence. These data will aid in building a surveillance, preparedness, and response plan for dengue virus infections in the Zanzibar Archipelago.Key words: dengue, seroprevalence, Zanzibar, viruses, vector-borne infections  相似文献   
40.

Introduction

Germline heterozygous mutations in the tumor suppresser NF1 gene cause a cancer predisposition syndrome known as neurofibromatosis type 1 (NF1). This disease is one of the most common multisystem disorders with an estimated incidence of 1 in 3,000 to 1 in 4,000 births. Clinically, NF1 patients are prone to develop “café au lait” spots, neurofibromas, Lisch nodules, freckling of the axillary, or inguinal region and optic nerve gliomas.

Materials and methods

In the present study, we report clinical and molecular findings of five unrelated patients and seven cases from four families with NF1 from UAE. To reveal the genetic defects underlying NF1 in our cohort of patients, we screened the whole coding and splice site regions of the NF1 gene. In addition, MLPA or CGH array has been used to screen for structural variations including deletions, indels, and complex rearrangements.

Results

This resulted in the identification of five distinct novel mutations and two previously reported ones. These variations included three missense and one nonsense mutations, one single base, one dinucleotide, and one large deletion.

Conclusion

Four mutations were inherited, and the remaining were absent from both parents and therefore are “de novo” mutations. This analysis represents the spectrum of NF1 mutations in UAE and supports the premise of absence of hotspot mutations in the NF1 gene. Moreover, no obvious genotype-phenotype correlations were observed in our patients.  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