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   1106篇
  免费   80篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   75篇
妇产科学   35篇
基础医学   76篇
口腔科学   10篇
临床医学   124篇
内科学   225篇
皮肤病学   7篇
神经病学   93篇
特种医学   28篇
外科学   194篇
综合类   46篇
一般理论   4篇
预防医学   156篇
眼科学   40篇
药学   26篇
肿瘤学   46篇
  2023年   6篇
  2022年   7篇
  2021年   17篇
  2020年   14篇
  2019年   27篇
  2018年   18篇
  2017年   25篇
  2016年   23篇
  2015年   23篇
  2014年   33篇
  2013年   41篇
  2012年   66篇
  2011年   81篇
  2010年   36篇
  2009年   44篇
  2008年   53篇
  2007年   55篇
  2006年   51篇
  2005年   59篇
  2004年   44篇
  2003年   43篇
  2002年   38篇
  2001年   27篇
  2000年   32篇
  1999年   28篇
  1998年   15篇
  1997年   9篇
  1996年   8篇
  1995年   13篇
  1994年   10篇
  1993年   8篇
  1992年   13篇
  1991年   27篇
  1990年   16篇
  1989年   20篇
  1988年   10篇
  1987年   28篇
  1986年   14篇
  1985年   8篇
  1984年   15篇
  1982年   6篇
  1981年   9篇
  1980年   6篇
  1974年   6篇
  1973年   7篇
  1972年   4篇
  1970年   6篇
  1969年   7篇
  1968年   5篇
  1966年   5篇
排序方式: 共有1187条查询结果,搜索用时 562 毫秒
41.
42.

Background

Nearly one in four Australian adults is vitamin D deficient (serum 25-hydroxyvitamin D concentrations [25(OH)D] < 50 nmol L–1) and current vitamin D intakes in the Australian population are unknown. Internationally, vitamin D intakes are commonly below recommendations, although estimates generally rely on food composition data that do not include 25(OH)D. We aimed to estimate usual vitamin D intakes in the Australian population.

Methods

Nationally representative food consumption data were collected for Australians aged ≥ 2 years (n = 12,153) as part of the cross-sectional 2011–2013 Australian Health Survey (AHS). New analytical vitamin D food composition data for vitamin D3, 25(OH)D3, vitamin D2 and 25(OH)D2 were mapped to foods and beverages that were commonly consumed by AHS participants. Usual vitamin D intakes (µg day–1) by sex and age group were estimated using the National Cancer Institute method.

Results

Assuming a 25(OH)D bioactivity factor of 1, mean daily intakes of vitamin D ranged between 1.84 and 3.25 µg day–1. Compared to the estimated average requirement of 10 µg day–1 recommended by the Institute of Medicine, more than 95% of people had inadequate vitamin D intakes. We estimated that no participant exceeded the Institute of Medicine's Upper Level of Intake (63–100 µg day–1, depending on age group).

Conclusions

Usual vitamin D intakes in Australia are low. This evidence, paired with the high prevalence of vitamin D deficiency in Australia, suggests that data-driven nutrition policy is required to safely increase dietary intakes of vitamin D and improve vitamin D status at the population level.  相似文献   
43.
BACKGROUND: The risk of transfusion transmitted viral infection is now so low that mathematical modelling is required to estimate the residual risk. The first national viral risk estimates for hepatitis B virus (HBV), human immunodeficiency virus (HIV) and hepatitis C virus (HCV) were recently published by the Australian Red Cross Blood Service. Using several refinements to the original methodology, as well as an additional 2 years of data, new risk estimates have been derived. METHODS: Viral screening data for Australian donors for 2000/2003 were retrospectively analysed. The data were applied to three published models to estimate the residual risk of transmitting HIV, HBV, HCV or human T lymphotrophic virus (HTLV) by blood transfusion in Australia. RESULTS: Applying the three models to HBV, HIV and HCV, three point estimates of the residual risk per unit were calculated for each virus. The median point estimates were 1 in 1,339,000 for HBV, 1 in 1 in 7,299,000 for HIV, and 1 in 3,636,000 for HCV. Although the HTLV risk could not be equivalently calculated because of the lack of incident infection it was estimated to be considerably less than 1 in 1,000,000 using a separate method. CONCLUSIONS: The most current and accurate estimate of residual risk of viral transmission in Australia has been provided in the present study. The residual risk in Australia is exceptionally small, continuing to decrease and is generally less than European or US risk estimates. These new estimates demonstrate that for viral transmission the Australian blood supply is amongst the safest in the world, and provide a basis for evaluating the cost benefit of future viral testing methodologies.  相似文献   
44.
45.
Multiple pterygium syndrome (MPS) disorders are a phenotypically and genetically heterogeneous group of conditions characterized by multiple joint contractures (arthrogryposis), pterygia (joint webbing) and other developmental defects. MPS is most frequently inherited in an autosomal recessive fashion but X-linked and autosomal dominant forms also occur. Advances in genomic technologies have identified many genetic causes of MPS-related disorders and genetic diagnosis requires large targeted next generation sequencing gene panels or genome-wide sequencing approaches. Using the Illumina TruSightOne clinical exome assay, we identified a recurrent heterozygous missense substitution in TPM2 (encoding beta tropomyosin) in three unrelated individuals. This was confirmed to have arisen as a de novo event in the two patients with parental samples. TPM2 mutations have previously been described in association with a variety of dominantly inherited neuromuscular phenotypes including nemaline myopathy, congenital fibre-type disproportion, distal arthrogryposis and trismus pseudocamptodactyly, and in a patient with autosomal recessive Escobar syndrome and a nemaline myopathy. The three cases reported here had overlapping but variable features. Our findings expand the range of TMP2-related phenotypes and indicate that de novo TMP2 mutations should be considered in isolated cases of MPS-related conditions.  相似文献   
46.
47.
Objective  The aim of this study was to compare the outcomes of enucleation versus resection in patients with small pancreatic, ampullary, and duodenal neuroendocrine tumors (NETs). Methods  Multi-institutional retrospective review identified all patients with pancreatic and peri-pancreatic NETs who underwent surgery from January 1990 to October 2008. Patients with tumors ≤3 cm and without nodal or metastatic disease were included. Results  Of the 271 patients identified, 122 (45%) met the inclusion criteria and had either an enucleation (n = 37) and/or a resection (n = 87). Enucleated tumors were more likely to be in the pancreatic head (P = 0.003) or functioning (P < 0.0001) and, when applicable, less likely to result in splenectomy (P = 0.0003). The rate of pancreatic fistula formation was higher after enucleation (P < 0.01), but the fistula severity tended to be worse following resection (P = 0.07). The enucleation and resection patients had similar operative times, blood loss, overall morbidity, mortality, hospital stay, and 5-year survival. However, for pancreatic head tumors, enucleation resulted in decreased blood loss, operative time, and length of stay compared to pancreaticoduodenectomy (P < 0.05). Conclusion  These data suggest that most outcomes of enucleation and resection for small pancreatic and peri-pancreatic NETs are comparable. However, enucleation has better outcomes than pancreaticoduodenectomy for head lesions and the advantage of preserving splenic function for tail lesions. Presented at the 2009 American Hepatopancreaticobiliary Association, March 14, 2009, Miami, FL American College of Surgeons Resident Research Scholarship, NIH Grant T32 CA009614 Physician Scientist Training in Cancer Medicine.  相似文献   
48.
BackgroundHigher postoperative quadriceps function has been positively associated with surgical outcomes after anterior cruciate ligament reconstruction (ACLR). However, the impact of autograft harvest and/or a concomitant meniscal procedure on the recovery of quadriceps strength is not well defined.PurposeTo describe postoperative recovery of quadriceps strength following ACLR related to autograft selection, meniscal status, and sex.Study DesignRetrospective Cohort.MethodsOne hundred and twenty-five participants who underwent ACLR with either a hamstring tendon (HT), bone-patellar tendon-bone (BPTB) or quadriceps tendon (QT) autograft were included. At postoperative months 3, 6 and 9, each participant completed an isometric quadriceps strength testing protocol at 90-degrees of knee flexion. Participants’ quadriceps average peak torque (Q-AvgPKT), average peak torque relative to body weight (Q-RPKT), and calculated limb symmetry index (Q-LSI) were collected and used for data analysis. Patients were placed in groups based on sex, graft type, and whether they had a concomitant meniscal procedure at the time of ACLR. At each time point, One-way ANOVAs, independent samples t-test and chi-square analyses were used to test for any between-group differences in strength outcomes.ResultsAt three months after ACLR, Q-RPKT was significantly higher in those with the HT compared to the QT. At all time points, males had significantly greater Q-RPKT than females and HT Q-LSI was significantly higher than BPTB and QT. A concomitant meniscal procedure at the time of ACLR did not significantly affect Q-LSI or Q-RPKT at any testing point.ConclusionThis study provides outcomes that are procedure specific as well as highlights the objective progression of quadriceps strength after ACLR. This information may help better-define the normal recovery of function, as well as guide rehabilitation strategies after ACLR.Level of Evidence3  相似文献   
49.
50.
There are many opportunities for short-term medical service internationally. Prerequisite preparation must include consideration of motivation, flexibility, culturally sensitive health care, and problems in communication and patient approach. Practical considerations require recognizing the importance of choice of locale, lack of materials and equipment, health concerns, travel, and expenses. A reference for opportunities available and a list of articles suggested as supplementary reading are provided.  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