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   469篇
  免费   76篇
  国内免费   2篇
耳鼻咽喉   6篇
儿科学   11篇
妇产科学   8篇
基础医学   73篇
口腔科学   55篇
临床医学   30篇
内科学   63篇
皮肤病学   15篇
神经病学   35篇
特种医学   24篇
外科学   114篇
预防医学   20篇
眼科学   7篇
药学   15篇
中国医学   1篇
肿瘤学   70篇
  2024年   1篇
  2023年   4篇
  2022年   10篇
  2021年   30篇
  2020年   13篇
  2019年   26篇
  2018年   28篇
  2017年   27篇
  2016年   28篇
  2015年   27篇
  2014年   28篇
  2013年   51篇
  2012年   39篇
  2011年   50篇
  2010年   14篇
  2009年   10篇
  2008年   21篇
  2007年   21篇
  2006年   15篇
  2005年   13篇
  2004年   19篇
  2003年   11篇
  2002年   10篇
  2001年   5篇
  2000年   7篇
  1999年   6篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1992年   1篇
  1990年   2篇
  1989年   5篇
  1987年   4篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1976年   2篇
  1975年   1篇
  1974年   2篇
  1973年   2篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
  1965年   1篇
排序方式: 共有547条查询结果,搜索用时 15 毫秒
61.
OBJECTIVES: To determine whether concentrations of beta-HCG in cervicovaginal secretions could predict spontaneous preterm birth (SPB) in asymptomatic high risk pregnancies. METHODS: A cohort study was undertaken with cervicovaginal samples collected from 540 pregnant women between 20 to 28 weeks of gestation. Levels of beta-HCG were measured by ELISA test. RESULTS: There was 3.2-fold increase in cervicovaginal beta-HCG concentrations among patients with SPB vs. term delivery. A single cervicovaginal beta-HCG > 77.8 mIU/ml, between 20 and 28 weeks' gestation, identified patients with subsequent SPB vs. term delivery with sensitivity of 87.5% (95% CI: 47.4-97.9) and a specificity of 97% (95% CI: 86.5-99.4) with positive and negative predictive values of 88.5% and 98%, respectively. Multiple logistic regression indicates that cervicovaginal beta-HCG level > 77.8 mIU/ml was an independent predictor of SPB (adjusted odds ratio 19.97, 95% CI: 10.65-37.45). Conclusions: Cervicovaginal beta-HCG is a sensitive and specific predictor of patients with subsequent preterm delivery.  相似文献   
62.
63.
OBJECTIVE: The study purpose was to determine the efficacy of steroid and antiviral therapy in the management of idiopathic sudden sensorineural hearing loss (SSNHL). STUDY DESIGN AND SETTING: We conducted a retrospective study of patients presenting to an academic tertiary care center. Fifty-one patients were evaluated. All patients were placed on the same treatment protocol. RESULTS: Thirty-seven patients (73%) had recovery of hearing. Ninety-one percent of patients with vertigo and all patients with mid-frequency hearing loss and up-sloping hearing loss recovered with treatment (P < 0.05). Recovery was significantly related to age, onset of hearing loss, and audiogram type; however outcome was not significantly related to gender, vertigo, tinnitus, or laterality (P < 0.05). CONCLUSION: Our treatment protocol produced a recovery rate, which exceeds the spontaneous recovery rate. Unlike prior studies, all patients with up-sloping and mid-frequency SSNHL had recovery. In addition, vertigo did not indicate a poor prognosis. SIGNIFICANCE: Antiviral therapy and increased length of steroid treatment may play a role in the improved recovery rates.  相似文献   
64.
65.
66.
Background The aim of this study was to investigate the potential of 99mTc–Evans blue for discriminating the sentinel lymph node in multitiered lymph node sequences by using an ovine model. 99mTc–Evans blue is an agent that has both radioactive and color signals in a single dose. Previous studies in smaller animal models suggested that this agent could have advantages over the dual-injection technique of radiocolloid/blue dye. Methods Doses of 99mTc–Evans blue (∼ 21 MBq) containing Evans blue dye (approximately 4 mg) were administered to the hind limbs or fore limbs of sheep to map the lymphatic drainage patterns, validate its ability to identify the sentinel lymph node, and examine the reproducibility of the technique. The study protocol was repeated with 99mTc–antimony trisulfide colloid and Patent Blue V dye. After the operative exposure, lymph nodes were identified with the gamma probe and then excised and analyzed for radioactivity (percentage of injected dose) and blue color. Results After the administration of 99mTc–Evans blue, all lymph nodes harvested (35 of 35) in either short chains or long basins were hot and blue. The sentinel lymph nodes concentrated more radioactivity than the second-tier nodes to the extent of 2:1 to 215:1. For radiocolloid/Patent Blue V, the ratios were lower, at 2:1 to 3:1. Conclusions 99mTc–Evans blue was found to better discriminate the sentinel lymph node than 99mTc–antimony trisulfide colloid/Patent Blue V in variable multitier lymph node anatomy, and it is an agent that promises to have positive clinical applications.  相似文献   
67.
68.
The association between pretransplant serum albumin concentration and post‐transplant outcomes in kidney transplant recipients is unclear. We hypothesized that in transplant‐waitlisted hemodialysis patients, lower serum albumin concentrations are associated with worse post‐transplant outcomes. Linking the 5‐year patient data of a large dialysis organization (DaVita) to the Scientific Registry of Transplant Recipients, we identified 8961 hemodialysis patients who underwent first kidney transplantation. Mortality or graft failure and delayed graft function (DGF) risks were estimated by Cox regression (hazard ratio [HR]) and logistic regression (Odds ratio [OR]), respectively. Patients were 48 ± 13 years old and included 37% women and 27% diabetics. The higher pretransplant serum albumin was associated with lower mortality, graft failure and DGF risk even after multivariate adjustment for case‐mix, malnutrition–inflammation complex and transplant related variable. Every 0.2 g/dL higher pretransplant serum albumin concentration was associated with 13% lower all‐cause mortality (HR = 0.87 [95% confidence interval: 0.82–0.93]), 17% lower cardiovascular mortality (HR = 0.83[0.74–0.93]), 7% lower combined risk of death or graft failure (HR = 0.93[0.89–0.97]) and 4% lower DGF risk (OR = 0.96[0.93–0.99]). Hence, lower pretransplant serum albumin level is associated with worse post‐transplant outcomes. Clinical trials to examine interventions to improve nutritional status in transplant‐waitlisted hemodialysis patients and their impacts on post‐transplant outcomes are indicated.  相似文献   
69.
The heterogeneity of multiple case breast cancer families that do not carry mutations in BRCA1 or BRCA2 (non‐BRCA1/2 families) poses a challenge to the identification of breast cancer susceptibility genes. The aim of this study was to determine whether intrafamilial concordance in breast cancer pathology could identify subgroups of non‐BRCA1/2 families with consistent genotypic features. Invasive breast cancers were reviewed from 84 individuals belonging to 30 multiple‐case families; BRCA1 (n = 9), BRCA2 (n = 10), and non‐BRCA1/2 (n = 11). Hierarchical cluster analysis based on histopathology and age at first diagnosis was then used to specify three subgroups designated Clusters 1–3. The genomic features of non‐BRCA1/2 families were examined by genome wide linkage and FGFR2 SNP genotyping, according to whether they showed cluster‐concordant or cluster‐mixed familial pathology. The majority of pathogenic BRCA1 mutation carriers (80%) fell into a single cluster. In contrast pathogenic BRCA2 mutation carriers were distributed across all three clusters and within families, cluster groups were also generally mixed. Most non‐BRCA1/2 mutation carriers belonged to Cluster 3 (71%). Genome wide linkage data from five non‐BRCA1/2 Cluster 3‐concordant families were compared with four mixed cluster non‐BRCA1/2 families. This revealed a number of distinct linkage peaks, including some regions previously associated with breast cancer susceptibility. The distribution of low risk alleles in FGFR2 was not different between these two subgroups (P = 0.237). The pattern of breast cancer pathology concordance amongst family members may assist the investigation of breast cancer susceptibility in multiple case families. © 2010 Wiley‐Liss, Inc.  相似文献   
70.
Homocysteine has been implicated in promoting atherosclerotic and thrombotic vascular disease. During the last decade, the utility of homocysteine in predicting risk for atherothrombotic vascular disease has been evaluated in several observational studies in a large number of patients. These studies show that the overall risk for vascular disease is small, with prospective, longitudinal studies reporting a weaker association between homocysteine and atherothrombotic vascular disease compared to retrospective case-control and cross-sectional studies. Furthermore, randomized controlled trials of homocysteine-lowering therapy have failed to prove a causal relationship. On the basis of these results, there is currently insufficient evidence to recommend routine screening and treatment of elevated homocysteine concentrations with folic acid and other vitamins to prevent atherothrombotic vascular disease. This review outlines the metabolism and pathophysiology of homocysteine, highlights the results of homocysteine observational and interventional trials, and presents areas of uncertainty and potential future work.  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