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   10901篇
  免费   786篇
  国内免费   82篇
耳鼻咽喉   85篇
儿科学   319篇
妇产科学   177篇
基础医学   1605篇
口腔科学   180篇
临床医学   1005篇
内科学   1609篇
皮肤病学   130篇
神经病学   2054篇
特种医学   177篇
外科学   619篇
综合类   309篇
一般理论   6篇
预防医学   1903篇
眼科学   114篇
药学   1110篇
  1篇
中国医学   100篇
肿瘤学   266篇
  2024年   33篇
  2023年   233篇
  2022年   272篇
  2021年   438篇
  2020年   433篇
  2019年   508篇
  2018年   414篇
  2017年   418篇
  2016年   430篇
  2015年   349篇
  2014年   516篇
  2013年   1207篇
  2012年   436篇
  2011年   493篇
  2010年   400篇
  2009年   465篇
  2008年   500篇
  2007年   432篇
  2006年   430篇
  2005年   357篇
  2004年   315篇
  2003年   281篇
  2002年   259篇
  2001年   193篇
  2000年   159篇
  1999年   133篇
  1998年   155篇
  1997年   133篇
  1996年   105篇
  1995年   104篇
  1994年   81篇
  1993年   74篇
  1992年   90篇
  1991年   89篇
  1990年   58篇
  1989年   55篇
  1988年   46篇
  1987年   46篇
  1986年   35篇
  1985年   72篇
  1984年   78篇
  1983年   32篇
  1982年   62篇
  1981年   64篇
  1980年   41篇
  1979年   41篇
  1978年   39篇
  1977年   36篇
  1976年   41篇
  1975年   33篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
目的研究性别对肥胖哮喘患儿吸入糖皮质激素(ICS)治疗前后肺功能的影响。方法190例哮喘患儿根据性别分为男性 组(102例,正常体质量组/肥胖组57/45)、女性组(88例正常体质量组/肥胖组46/42),检测所有患儿治疗前及规范化ICS治疗1 年后肺功能,包括第1秒时间肺活量(FEV1)、用力肺活量(FVC)、用力呼气50%流量(MEF50)、用力呼气25%流量(MEF25)。结 果治疗前各组肺功能男女性比较无统计学差异(均P>0.05)。ICS治疗1年后,正常体质量男女性组FVC%、FEV1%较治疗前 均明显升高(P<0.05);肥胖男性组FVC%、FEV1%较治疗前明显升高(P<0.05),而肥胖女性组仅FVC%较治疗前升高(P< 0.05)。结论ICS治疗能够改善哮喘大气道通气功能,性别对哮喘ICS治疗大气道通气功能的改善依赖于体质量指数,表现为 性别对正常体质量哮喘患儿ICS治疗影响作用较小,而女性肥胖哮喘患儿肺功能改善程度明显低于男性肥胖哮喘患儿。  相似文献   
72.
目的:回顾性分析肝豆状核变性(WD )患者的临床分型、实验室和影像学检查,加强对该病的认识并提高诊断率。方法收集2011年1月至2014年9月该院确诊的WD患者的临床资料,并进行统计学分析。结果不同年龄、民族、性别的WD患者,其初次发病年龄、临床分型、实验室检查均存在着一定的差异,男性患者的发病年龄明显早于女性,神经型WD患者的M RI均存在低密度影改变。结论遗传并不是影响WD的唯一因素,性别、年龄、民族也可能是影响WD患者初次发病年龄及临床症状的因素之一。  相似文献   
73.
The processes of cancer initiation, progression, and response to therapy are affected by the sex of cancer patients. Immunotherapy responses largely depend on the tumor microenvironment (TME), but how sex may shape some TME features, remains unknown. Here, we analyzed immune infiltration signatures across 19 cancer types from 1771 male and 1137 female patients in The Cancer Genome Atlas to evaluate how sex may affect the tumor mutational burden (TMB), immune scores, stromal scores, tumor purity, immune cells, immune checkpoint genes, and functional pathways in the TME. Pan‐cancer analyses showed higher TMB and tumor purity scores, as well as lower immune and stromal scores in male patients as compared to female patients. Lung adenocarcinoma, lung squamous carcinoma, kidney papillary carcinoma, and head and neck squamous carcinoma showed the most significant sex biases in terms of infiltrating immune cells, immune checkpoint gene expression, and functional pathways. We further focused on lung adenocarcinoma samples in order to identify and validate sex‐specific immune cell biomarkers with prognostic potential. Overall, sex may affect the tumor microenvironment, and sex‐specific TME biomarkers may help tailor cancer immunotherapy in certain cancer types.  相似文献   
74.
Visual attention can be allocated to locations or objects, leading to enhanced processing of information at the specific location (space-based effects) or specific object (object-based effects). Previous studies have observed object-based effects to be smaller and less robust than space-based effects, with large individual differences in their temporal occurrence. Studies on space- and object-based effects are often based on a two-rectangle paradigm in which targets appear at cued locations more often than uncued locations. It is, however, unclear whether and how the target''s spatial probability affects the temporal occurrence of these effects. In three experiments with different cue validities (80%, 50% and 33%), we systematically changed the interval between the cue and the target from 50 to 600 ms. On a group level and for individuals, we examined how cue validity affects the occurrence of object- and space-based effects. We observed that the magnitude and the prevalence of space-based effects heavily decreased with reduced cue validity. Object-based effects became even more sparse and turned increasingly negative with decreasing cue validity, representing a different-object rather than a same-object advantage. These findings indicate that changes in cue-validity affect both space- and object-based effects, but it does not account for the low prevalence and magnitude of object-based effects.  相似文献   
75.
Age and sex effects on brain morphology   总被引:6,自引:0,他引:6  
1. 1. Brain morphology can be assessed readily in vivo using magnetic resonance imaging (MRI).
2. 2. In this study, the effects of age and sex on whole-brain morphology were examined using an operator-controlled computer-segmentation protocol.
3. 3. Results indicated that age was associated with gray-matter volume reduction.
4. 4. Brain-size differences between males and females were primarily attributable to whitematter volume.
5. 5. This study confirms the importance of controlling for age and sex in brain-morphology studies.
  相似文献   
76.

Introduction

African Americans' (AAs) late-onset Alzheimer's disease (LOAD) genetic risk profile is incompletely understood. Including clinical covariates in genetic analyses using informed conditioning might improve study power.

Methods

We conducted a genome-wide association study (GWAS) in AAs employing informed conditioning in 1825 LOAD cases and 3784 cognitively normal controls. We derived a posterior liability conditioned on age, sex, diabetes status, current smoking status, educational attainment, and affection status, with parameters informed by external prevalence information. We assessed association between the posterior liability and a genome-wide set of single-nucleotide polymorphisms (SNPs), controlling for APOE and ABCA7, identified previously in a LOAD GWAS of AAs.

Results

Two SNPs at novel loci, rs112404845 (P = 3.8 × 10?8), upstream of COBL, and rs16961023 (P = 4.6 × 10?8), downstream of SLC10A2, obtained genome-wide significant evidence of association with the posterior liability.

Discussion

An informed conditioning approach can detect LOAD genetic associations in AAs not identified by traditional GWAS.  相似文献   
77.
BackgroundThis study profiles ceramides extracted from visceral and subcutaneous adipose tissue of human subjects by liquid chromatography‐mass spectrometry to determine a correlation with status of diabetes and gender.MethodsSamples of visceral and abdominal wall subcutaneous adipose tissue (n = 36 and n = 31, respectively) were taken during laparoscopic surgery from 36 patients (14 nondiabetic, 22 diabetic and prediabetic) undergoing bariatric surgery with a body mass index (BMI) >35 kg/m2 with ≥1 existing comorbidity or BMI ≥40 kg/m2. Sphingolipids were extracted and analyzed using liquid chromatography‐mass spectrometry.ResultsAfter logarithm 2 conversion, paired analysis of visceral to subcutaneous tissue showed differential accumulation of Cer(d18:1/16:0), Cer(d18:1/18:0), and Cer(d18:1/24:1) in visceral tissue of prediabetic/diabetic female subjects, but not in males. Within‐tissue analysis showed higher mean levels of ceramide species linked to insulin resistance, such as Cer(d18:1/18:0) and Cer(d18:1/16:0), in visceral tissue of prediabetic/diabetic patients compared with nondiabetic subjects and higher content of Cer(d18:1/14:0) in subcutaneous tissue of insulin‐resistant female patients compared with prediabetic/diabetic males. Statistically significant differences in mean levels of ceramide species between insulin‐resistant African American and insulin‐resistant Caucasian patients were not evident in visceral or subcutaneous tissue.ConclusionsAnalysis of ceramides is important for developing a better understanding of biological processes underlying type 2 diabetes, metabolic syndrome, and obesity. Knowledge of the accumulated ceramides/dihydroceramides may reflect on the prelipolytic state that leads the lipotoxic phase of insulin resistance and may shed light on the predisposition to insulin resistance by gender.  相似文献   
78.
Previous studies revealed inconsistent results between coffee drinking and metabolic syndrome (MetS). The aim of the study was to evaluate the relationship between habitual coffee drinking and the prevalence of MetS among men and women. We conducted a nationwide, cross-sectional study using 23,073 adults obtained from the Taiwan Biobank database (mean ± SD (range) age, 54.57 ± 0.07 (30–79) years; 8341 men and 14,731 (63.8%) women). Adults who drank more than one cup of coffee per day (n = 5118) and those who drank less than one cup per day (n = 4515) were compared with nondrinkers (n = 13,439). Multivariate logistic regression models were used to evaluate the risk of MetS between the two groups. Separate models were also estimated for sex-stratified and habitual coffee-type-stratified (black coffee (BC), coffee with creamer (CC), and coffee with milk (CM)) subgroup analyses. The MetS diagnosis was based on at least three of the five metabolic abnormalities. Coffee drinkers (≥1 cup/day) had a significantly lower prevalence of MetS than nondrinkers (AOR (95% CI): 0.80 (0.73–0.87)). Women who drank any amount of coffee and any type of coffee were more likely to have a significantly lower prevalence of MetS than nondrinkers. Only men who drank more than one cup of coffee per day or black coffee drinkers were more likely to have a lower prevalence of MetS. Our study results indicate that adults with habitual coffee drinking behaviors of more than one cup per day were associated with a lower prevalence of MetS. Moreover, women could benefit from habitual coffee drinking of all three coffee types, whereas men could only benefit from drinking BC.  相似文献   
79.
Despite research that suggests flavonoids protect against metabolic syndrome (MetS) and evidence that intake of these compounds differs by race, knowledge about whether flavonoid–MetS associations vary among racial groups is limited. This study sought to estimate usual total flavonoid intake in African American and White adults and assess its sex- and sex/race-specific associations with MetS and its risk factors. Analysis of cross-sectional data from 1837 adults participating in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study were analyzed. Usual total flavonoid intake was estimated using the NCI Method, and logistic regression measured its linkages with health outcomes. Among males overall and when stratified by race, odds of MetS and its risk factors low high-density lipoprotein cholesterol (HDL-C) and elevated glucose were lower at the 75th percentile of usual total flavonoid intake than at the 25th percentile (OR for MetS = 0.62; 95% CI = 0.53, 0.71). However, low HDL-C and elevated glucose were positively associated with usual flavonoid intake among females. The comparable associations by race within sex imply that the relationships between flavonoid and health outcomes may be evident across an array of intakes.  相似文献   
80.
  目的  了解中山市成年居民失眠症状现况。  方法  2017年2 — 5月,采用随机抽样方法对中山市25个乡镇和城区的12 182名 > 18岁成年居民进行失眠症状调查。  结果  中山市成年居民失眠症状检出率为10.02 %,其中女性的检出率为11.76 %,男性为8.17 %;成年居民失眠症状总得分为(1.19 ± 0.01)分,入睡困难得分为(0.37 ± 0.01)分,再入睡困难得分为(0.48 ± 0.01)分,早醒得分为(0.35± 0.01)分;回归分析结果显示,除了学历和家庭所在地之外,性别、年龄、职业、婚姻状况、子女人数和家庭经济水平均为失眠症状的影响因素(P < 0.05)。  结论  中山市成人失眠症状的检出率较高;性别、年龄、职业、婚姻状况、子女人数和家庭经济水平等都是失眠症状的主要影响因素。  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