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   984篇
  免费   69篇
  国内免费   11篇
耳鼻咽喉   20篇
儿科学   36篇
妇产科学   13篇
基础医学   139篇
口腔科学   23篇
临床医学   75篇
内科学   149篇
皮肤病学   16篇
神经病学   21篇
特种医学   143篇
外科学   87篇
综合类   41篇
一般理论   1篇
预防医学   29篇
眼科学   9篇
药学   56篇
中国医学   5篇
肿瘤学   201篇
  2023年   10篇
  2022年   13篇
  2021年   20篇
  2020年   19篇
  2019年   21篇
  2018年   31篇
  2017年   21篇
  2016年   29篇
  2015年   31篇
  2014年   52篇
  2013年   61篇
  2012年   60篇
  2011年   49篇
  2010年   35篇
  2009年   38篇
  2008年   55篇
  2007年   39篇
  2006年   27篇
  2005年   32篇
  2004年   25篇
  2003年   24篇
  2002年   24篇
  2001年   13篇
  2000年   11篇
  1999年   14篇
  1998年   45篇
  1997年   34篇
  1996年   20篇
  1995年   14篇
  1994年   15篇
  1993年   19篇
  1990年   14篇
  1989年   12篇
  1988年   11篇
  1987年   11篇
  1986年   13篇
  1985年   18篇
  1984年   4篇
  1983年   7篇
  1982年   10篇
  1981年   7篇
  1980年   11篇
  1979年   2篇
  1978年   9篇
  1977年   8篇
  1976年   4篇
  1975年   4篇
  1972年   3篇
  1971年   4篇
  1968年   2篇
排序方式: 共有1064条查询结果,搜索用时 15 毫秒
21.
22.
Background

 Under the Affordable Care Act, Medicaid expansion effective 1 January 2014 aimed to increase access to health care. We sought to determine the association of Medicaid expansion with disparities in utilization of breast reconstruction.

Methods

Non-Hispanic Black (NHB) and White (NHW) breast cancer patients undergoing mastectomy +/? reconstruction between 2010 and 2017 were selected from the National Cancer Database. Annual trends for utilization of breast reconstruction by race, income, and education were evaluated by Medicaid expansion status using difference-in-differences regression analyses. Medicaid expansion was categorized by expansion date as early (2010–2013), 2014 (1/2014), late (after 1/2014), or no expansion.

Results

Of 443,607 patients, 36.3% (n = 161,128) underwent reconstruction, 13.1% (n = 58,249) were NHB, 16.8% (n = 74,430) had median income < $40,227, and 17.1% (n = 75,718) were in the lowest education quartile. In non-expansion states, lower proportions of NHB patients underwent reconstruction than NHW patients in all years, with the smallest disparity (NHB% ? NHW%) (? 6.4%) in 2017. Decreases in disparities between NHB and NHW patients were seen with the smallest difference observed in 2014 (? 2.5%) in early-expansion states, in 2017 (? 0.7%) in 1/2014 expansion states, and in 2017 (? 4.5%) in late-expansion states. Similar findings for convergence of reconstruction utilization rates for the lowest two education levels and lowest two income quartiles were found with Medicaid expansion, with no convergence seen in non-expansion states over the study period.

Conclusions

Some improvement in breast reconstruction disparities followed Medicaid expansion. Failure to improve parity without Medicaid expansion should be a consideration with any modifications to Medicaid access.

  相似文献   
23.
The incidence of Papillary Thyroid Carcinoma in a Thyroglossal Cyst is rare. Only about 160 cases have been reported in the last 85 years. We report a case of Thyroglossal Cyst who underwent Sistrunk &#x2019;s Operation. The Cyst was reported to contain a focus of papillary thyroid carcinoma. In the absence of metastases in thyroid gland and neck nodes, only thyroid suppression with Thyroxine was given. After I year of follow-up there are no metastases. The importance of Sistrunk&#x2019;s operation lies not only in complete removal of Thyroglossal Cyst but also in management of small foci of Papillary thyroid Carcinoma.  相似文献   
24.
BACKGROUND: Boys and young men with hemophilia treated with factor infusions before 1985 had a substantial risk of acquiring the human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome. This study was designed to assess the effects of HIV and hemophilia per se on neurological function in a large cohort of subjects with hemophilia, and to investigate the relationships between neurological disease and death during follow-up. METHODS: Three hundred thirty-three boys and young men (207 HIV seropositive and 126 HIV seronegative) were evaluated longitudinally in a multicenter, multidisciplinary study. Neurological history and examination were conducted at baseline and annually for 4 years. The relationship between neurological variables, HIV serostatus, CD4+ cell counts, and vital status at the conclusion of the study was examined using logistic regression models. RESULTS: The risks of nonhemophilia-associated muscle atrophy, behavior change, and gait disturbance increased with time in immune compromised HIV-seropositive subjects compared with HIV seronegative or immunologically stable HIV-seropositive subjects. The risk of behavior change in immune compromised HIV-seropositive hemophiliacs, for example, rose to 60% by year 4 versus 10% to 17% for the other study groups. Forty-five subjects (13.5%), all of whom were HIV seropositive, died by year 4. Subjects who died had had increased risks of hyperreflexia, nonhemophilia-associated muscle atrophy, and behavior change. CONCLUSIONS: These results indicate that immune compromised, HIV-seropositive hemophiliacs have high rates of neurological abnormalities over time and that neurological abnormalities were common among subjects who later died. By contrast, immunologically stable HIV-seropositive subjects did not differ from the HIV-seronegative participants. Hemophilia per se was associated with progressive abnormalities of gait, coordination, and motor function.  相似文献   
25.
26.
Setting: Numerous knowledge gaps hamper the prevention and treatment of childhood drug-resistant tuberculosis (TB). Identifying research priorities is vital to inform and develop strategies to address this neglected problem.Objective: To systematically identify and rank research priorities in childhood drug-resistant TB.Design: Adapting the Child Health and Nutrition Research Initiative (CHNRI) methodology, we compiled 53 research questions in four research areas, then classified the questions into three research types. We invited experts in childhood drug-resistant TB to score these questions through an online survey.Results: A total of 81 respondents participated in the survey. The top-ranked research question was to identify the best combination of existing diagnostic tools for early diagnosis. Highly ranked treatment-related questions centred on the reasons for and interventions to improve treatment outcomes, adverse effects of drugs and optimal treatment duration. The prevalence of drug-resistant TB was the highest-ranked question in the epidemiology area. The development type questions that ranked highest focused on interventions for optimal diagnosis, treatment and modalities for treatment delivery.Conclusion: This is the first effort to identify and rank research priorities for childhood drug-resistant TB. The result is a resource to guide research to improve prevention and treatment of drug-resistant TB in children.  相似文献   
27.
EBV and KSHV are both gamma-herpesviruses which express multiple viral microRNAs. Various methods have been used to investigate the functions of these microRNAs, largely through identification of microRNA target genes. Surprisingly, these related viruses do not share significant sequence homology in their microRNAs. A number of reports have described functions of EBV and KSHV microRNA targets, however only three experimentally validated target genes have been shown to be targeted by microRNAs from both viruses. More sensitive methods to identify microRNA targets have predicted approximately 60% of host targets could be shared by EBV and KSHV microRNAs, but by targeting different sequences in the host targets. In this review, we explore the similarities of microRNA functions and targets of these related viruses.  相似文献   
28.
29.
Our aim was to evaluate ophthalmological injuries associated with fractures of the orbitozygomaticomaxillary complex that required operative treatment, and we collected data retrospectively over a period of five years (2012-2016 inclusive). Of the 190 patients, 162 were male with a median age of 31 (IQR 25 -39) years. Assault was the most common mechanism of injury (125/190, 66%). Minor ophthalmic injuries (those unlikely to cause permanent visual disturbance) and major ophthalmic injuries (those with the potential to cause permanent visual disturbance) were recorded. The common minor ophthalmic injuries were: diplopia, enophthalmos, proptosis, subconjunctival haemorrhage, and restriction of the extraocular muscles. Commotio retinae, traumatic mydriasis, retro-orbital haemorrhage, and hyphaema were the common major ophthalmic injuries. All 13 different major ophthalmic injuries were recorded in the group who had had orbital fractures reconstructed, which suggested that more intraocular damage can be caused by this type of fracture than by others. Visual acuity was reduced in 26/190 patients with only four having persistent postoperative changes at six weeks. The odds ratio for those patients who had a major ophthalmological injury and were unable to drive was 0.07 (95% CI 0.02 to 0.21, p = 0.001), which was highly significant. Ophthalmological assessment is strongly recommended for patients with fractures of the orbitozygomaticomaxillary complex.  相似文献   
30.
Vascular remodelling is an adaptive mechanism, which counteracts pressure changes in blood circulation. Nicotine content in cigarette increases the risk of hypertension. The exact relationship between nicotine and vascular remodelling still remain unknown. Current study was aimed to determine the effect of clinically relevant dosage of nicotine (equivalent to light smoker) on aortic reactivity, oxidative stress markers and histomorphological changes. Twelve age-matched male Sprague-Dawley rats were randomly divided into two groups, i.e.: normal saline as control or 0.6 mg/kg nicotine for 28 days (i.p., n=6 per group). On day-29, the rats were sacrificed and the thoracic aorta was dissected immediately for further studies. Mean arterial pressure (MAP) and pulse pressure (PP) of nicotine-treated vs. control were significantly increased (p<0.05). Nicotine-treated group showed significant (p<0.05) increase tunica media thickness, and decrease in lumen diameter, suggesting vascular remodelling which lead to prior hypertension state. The phenylephrine (PE)-induced contractile response in nicotine group was significantly higher than control group (ED50=1.44×105 M vs. 4.9×106 M) (p<0.05~0.001). However, nicotine-treated rat showed significantly lower endothelium-dependent relaxation response to acetylcholine (ACh) than in control group (ED50=6.17×107 M vs. 2.82×107 M) (p<0.05), indicating loss of primary vascular function. Malondialdehyde (MDA), a lipid peroxidation marker was significantly higher in nicotine group. Superoxide dismutase (SOD) enzymatic activity and glutathione (GSH) were all reduced in nicotine group (p<0.05) vs. control, suggesting nicotine induces oxidative imbalance. In short, chronic nicotine administration impaired aortic reactivity, probably via redox imbalance and vascular remodelling mechanism.  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