全文获取类型
收费全文 | 45659篇 |
免费 | 4732篇 |
国内免费 | 1232篇 |
专业分类
耳鼻咽喉 | 212篇 |
儿科学 | 1068篇 |
妇产科学 | 350篇 |
基础医学 | 14170篇 |
口腔科学 | 487篇 |
临床医学 | 3371篇 |
内科学 | 8042篇 |
皮肤病学 | 1290篇 |
神经病学 | 1706篇 |
特种医学 | 2504篇 |
外国民族医学 | 9篇 |
外科学 | 2929篇 |
综合类 | 5154篇 |
现状与发展 | 12篇 |
一般理论 | 1篇 |
预防医学 | 2038篇 |
眼科学 | 402篇 |
药学 | 3445篇 |
9篇 | |
中国医学 | 1481篇 |
肿瘤学 | 2943篇 |
出版年
2024年 | 100篇 |
2023年 | 693篇 |
2022年 | 1204篇 |
2021年 | 1710篇 |
2020年 | 1497篇 |
2019年 | 1813篇 |
2018年 | 1935篇 |
2017年 | 1705篇 |
2016年 | 1639篇 |
2015年 | 1841篇 |
2014年 | 2695篇 |
2013年 | 3123篇 |
2012年 | 2413篇 |
2011年 | 2783篇 |
2010年 | 2218篇 |
2009年 | 2052篇 |
2008年 | 2144篇 |
2007年 | 2031篇 |
2006年 | 1823篇 |
2005年 | 1596篇 |
2004年 | 1584篇 |
2003年 | 1396篇 |
2002年 | 1179篇 |
2001年 | 1102篇 |
2000年 | 938篇 |
1999年 | 833篇 |
1998年 | 861篇 |
1997年 | 768篇 |
1996年 | 650篇 |
1995年 | 644篇 |
1994年 | 649篇 |
1993年 | 567篇 |
1992年 | 331篇 |
1991年 | 247篇 |
1990年 | 275篇 |
1989年 | 212篇 |
1988年 | 159篇 |
1987年 | 108篇 |
1986年 | 112篇 |
1985年 | 269篇 |
1984年 | 307篇 |
1983年 | 196篇 |
1982年 | 239篇 |
1981年 | 184篇 |
1980年 | 155篇 |
1979年 | 157篇 |
1978年 | 109篇 |
1977年 | 92篇 |
1976年 | 105篇 |
1975年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Symielle A. Gaston Nicolle S. Tulve 《International journal of hygiene and environmental health》2019,222(2):195-204
Objective
There is limited research on the association between phthalates and metabolic syndrome (MetS). Among adolescents, phthalate exposure, which can occur from multiple sources, has been linked to several risk factors for MetS. The objective was to investigate the association between urinary phthalate metabolite concentrations (i.e., mono-ethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), mono-benzyl phthalate (MBzP), mono-(3-carboxylpropyl) phthalate (MCPP), and di(2-ethylhexyl phthalate (DEHP)) and MetS in adolescents aged 12–19 years using the National Health and Nutrition Examination Survey (NHANES) data (2003–2014). A secondary aim was to assess if observed associations varied by a measure of socioeconomic status, economic adversity, which was defined using parental income and educational attainment as well as household food security.Methods
We used NHANES data which included physical examination, laboratory urinalysis and fasting blood profiles, and self-reported health characteristics and demographics. Physical examination and laboratory data were used to obtain values of MetS components and urinary phthalate metabolites. We created age-, sex-, and survey year-specific tertiles of creatinine-corrected urinary phthalate metabolites. Analysis was performed using appropriate weighting procedures that accounted for NHANES' complex sampling design. After univariate and bivariate analyses, we performed adjusted logistic regressions to test for associations between individual phthalate metabolites and MetS as well as MetS components and number of MetS components, separately, using the lowest tertile as the reference category. A cross-product term (phthalate metabolite*economic adversity) was subsequently added to adjusted models.Results
Among 918 participants (mean age 16 years, 45% female, 18% with economic adversity), the prevalence of MetS was 5.3%. Prior to adjustment, adolescents with MetS had marginally higher concentrations of phthalate metabolites than adolescents without MetS. There was a suggestive positive association between intermediate concentrations of MnBP and odds of MetS after adjustment (T2: Odds Ratio (OR)?=?2.66 (95% confidence interval: 0.98–7.24); T3: OR?=?2.11 (0.71–6.27)). Males with higher MnBP concentrations had higher odds of dyslipidemia; however, associations were mostly non-significant for females. Relationships between MiBP concentrations and odds of MetS varied by sex. Males with higher concentrations of MnBP and MiBP had greater odds of having a higher number of MetS components. Relationships between phthalate metabolites and MetS did not vary by economic adversity.Conclusion
There was a suggestive positive association between MnBP and MetS among adolescents. Associations between phthalate metabolites and MetS as well as MetS components may vary by sex, but may not vary by economic adversity. Further research of the relationships between phthalate exposures, MetS, and potential interactions with socioeconomic factors is warranted. 相似文献992.
993.
Yun Chen Na Wang Xiaolian Dong Jianfu Zhu Yue Chen Qingwu Jiang Chaowei Fu 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2021,31(8):2416-2425
Background and aimsSome amino acids (AAs) may be associated with type 2 diabetes (T2DM). This study aimed to determine the associations of individual AAs with the development of T2DM in rural Chinese adults.Methods and resultsA cohort study of 1199 individuals aged 18 years or older was conducted from 2006 to 2008 in a rural community of Deqing, China, a repeated survey was done in 2015 and data linkage with the electronic health records system was performed each year for identifying new T2DM cases. A high-performance liquid chromatography approach was used to measure the baseline serum concentrations of 15 AAs. Cox proportional hazards models were used to examine the associations between AAs and the risk of incident T2DM. A total of 98 new T2DM cases were identified during the follow-up of 12 years on average. Among 15 AAs, proline was associated with an increased risk of incident T2DM after adjusted for age, sex, body mass index, fasting plasma glucose, family history of T2DM, smoking status, alcohol use, and history of hypertension, the adjusted hazard ratio for 1-standard deviation increment was 1.20 (95% confidence interval: 1.00, 1.43). The association tended to be more marked in subjects younger than 60 years and overweight/obese subjects. Among participants without hypertension, proline and phenylalanine were associated with an increased risk of incident T2DM, while aspartic acid was associated with a decreased risk.ConclusionSerum proline was associated with the risk of incident T2DM in rural Chinese adults and might be a potential predictor. 相似文献
994.
Parampal S. Grewal Steven R.J. Lapere R. Rishi Gupta Mark Greve 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》2019,54(1):60-64
Objective
To determine the effectiveness of a macular buckle procedure without vitrectomy for the treatment of symptomatic myopic macular schisis.Design
Retrospective case series.Participants and methods
All patients who underwent surgery with placement of an NPB macular buckle (AJL Ophthalmic, Miñano, Álava, Spain) without vitrectomy for symptomatic myopic macular schisis were included. Visual acuity and anatomical outcomes based on optical coherence tomography (OCT) were reviewed.Results
Eight consecutive eyes from 7 patients were included. Six of the 7 patients were female and the mean age was 59 ± 6 years (range, 49–66 years). The mean follow-up duration was 11 ± 7 months (range, 3–23 months). Mean preoperative axial length was 29.54 ± 1.28 mm (range, 27.88–31.96 mm). Mean preoperative best-corrected visual acuity (BCVA) was 0.71 ± 0.29 logMAR (Snellen equivalent 20/103); mean postoperative BCVA was 0.46 ± 0.44 (Snellen equivalent 20/58; p = 0.19) and 87.5% of patients maintained or improved vision. Pre- and postoperative OCT images are included and discussed within. Preoperative ellipsoid zone status and postoperative central macular buckle indentation appear to be important in visual outcomes. Two patients required a buckle repositioning for persistent schisis. One patient developed a macular hole postoperatively that resolved with subsequent vitrectomy. There were no other complications.Conclusions
The macular buckle is an effective and promising therapeutic option for myopic macular schisis. 相似文献995.
Kiersten Schock Alex Ragan John T. Huang 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》2019,54(2):171-175
Objective
Several Canadian health authorities have defunded preoperative cataract history and physical examinations performed by general practitioners. While these authorities suggest that such decisions are evidence-based, we are unaware of reviews addressing this topic, nor have health authorities been forthcoming with evidence used in their decision-making processes. The objective of this study is to perform a comprehensive review of the literature regarding the value of preoperative histories and physical examinations in cataract surgery.Design
Systematic review.Methods
The following databases were searched: PubMed, MEDLINE, Cochrane Library, Google Scholar, Web of Science, EMBASE, CINAHL, and BIOSIS Previews. Only higher-level forms of evidence were assessed, including randomized controlled trials, cohort, and case-control studies. Two reviewers independently assessed titles and abstracts for concordance with inclusion criteria. Disagreements between authors were resolved by discussion.Results
We identified 3 articles that met our inclusion criteria: two prospective and one retrospective cohort studies. These articles suggest traditional preoperative histories and physical examinations could be replaced by a health questionnaire (Jastrzebski et al. and Reeves et al.) or eliminated altogether (Alboim et al.).Discussion
Scientific literature presently contains 3 studies suggesting that preoperative histories and physical examinations could be modified or eliminated. However, methodological weaknesses and data analysis derived from these studies suggests defunding preoperative medical examination may be premature.Conclusions
While finding efficiencies in medical care is admirable, physicians should be cautious in accepting recommendations that reduce checks ensuring perioperative safety. Further studies of better methodological quality should be completed to clarify the present evidence. 相似文献996.
Type 2 diabetes mellitus (T2DM) is a complicated metabolic disease and has become one of the significant medical problems worldwide. Researchers aim to provide fine-tuned treatment for T2DM with minimal exposed side effects. Nutraceuticals are compounds or materials and emerging evidence suggests that the use of nutraceuticals has recently been recognized as a promising option for the prevention and management of T2DM, such as probiotics and prebiotics, Vitamin D, n-3 long-chain polyunsaturated fatty acids, and Plant-derived nutraceuticals. This review attempts to show the most popular nutraceuticals and review their effects and possible mechanisms in the prevention or glycemic control of T2DM. 相似文献
997.
998.
999.
1000.
Aleksandra Cieluch Aleksandra Uruska Marcin Nowicki Ewa Wysocka Agata Grzelka-Woźniak Justyna Flotyńska Paweł Niedźwiecki Dorota Zozulińska-Ziółkiewicz 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2021,31(4):1219-1226
Background and aimsCholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP) are crucial proteins in reverse cholesterol transport. There are insufficient data on regulating these proteins by insulin therapy in type 1 diabetes mellitus (T1DM). We aimed to assess prospectively the impact of insulin therapy initiation on transfer proteins serum levels in adults with newly diagnosed T1DM.Methods and results57 adults with newly diagnosed T1DM were enrolled in the InLipoDiab1 Study. All participants were treated with subcutaneous insulin in the model of intensive insulin therapy since the diagnosis of diabetes. Serum PLTP and CETP concentrations were measured at diagnosis, after three weeks, six months, and after one year of insulin treatment, using the immunoenzymatic method ELISA.A significant decrease in PLTP and CETP concentrations were demonstrated during twelve months of insulin therapy in newly diagnosed T1DM. The dynamics of changes in the level of these proteins varied depending on the occurrence of remission after a year of the disease. In the group without remission, a significant decrease in PLTP and CETP levels appeared after six months of follow-up. The remission group was characterized by a decrease in proteins concentration only after one year of treatment. In the non-remission group, significant negative correlations were found between the daily dose of insulin and levels of PLTP and CETP.ConclusionExogenous insulin is an inhibitor of lipid transfer proteins involved in high-density lipoprotein cholesterol metabolism in the first year of treatment. 相似文献