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   11641篇
  免费   1607篇
  国内免费   317篇
耳鼻咽喉   386篇
儿科学   265篇
妇产科学   109篇
基础医学   2068篇
口腔科学   51篇
临床医学   1376篇
内科学   1102篇
皮肤病学   68篇
神经病学   309篇
特种医学   434篇
外国民族医学   16篇
外科学   1623篇
综合类   2122篇
预防医学   458篇
眼科学   197篇
药学   647篇
  12篇
中国医学   211篇
肿瘤学   2111篇
  2024年   59篇
  2023年   252篇
  2022年   471篇
  2021年   607篇
  2020年   638篇
  2019年   565篇
  2018年   489篇
  2017年   544篇
  2016年   644篇
  2015年   583篇
  2014年   819篇
  2013年   744篇
  2012年   623篇
  2011年   670篇
  2010年   518篇
  2009年   425篇
  2008年   471篇
  2007年   456篇
  2006年   432篇
  2005年   367篇
  2004年   325篇
  2003年   291篇
  2002年   256篇
  2001年   240篇
  2000年   219篇
  1999年   178篇
  1998年   175篇
  1997年   136篇
  1996年   139篇
  1995年   140篇
  1994年   115篇
  1993年   112篇
  1992年   91篇
  1991年   87篇
  1990年   73篇
  1989年   65篇
  1988年   57篇
  1987年   48篇
  1986年   67篇
  1985年   65篇
  1984年   43篇
  1983年   27篇
  1982年   39篇
  1981年   47篇
  1980年   35篇
  1979年   20篇
  1978年   24篇
  1977年   30篇
  1976年   10篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Background/objectiveObstructive sleep apnea (OSA) is independently associated with dyslipidemia, a surrogate marker of atherosclerosis. Low-density lipoprotein (LDL)-cholesterol is accepted as a major independent risk factor for cardiovascular disease. However, non-high-density lipoprotein (HDL)-cholesterol is a better marker of atherogenic dyslipidemia and recommended as a target of lipid lowering therapy. We aimed to assess the prevalence of atherogenic dyslipidemia, and relationship between OSA severity and serum LDL-cholesterol and non-HDL cholesterol levels in OSA patients.MethodsWe retrospectively evaluated treatment naïve 2361 subjects admitted to the sleep laboratory of a university hospital for polysomnography. All subjects’ lipid profile including total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and non-HDL-cholesterol were measured.ResultsOut of 2361 patients (mean age 49.6 ± 11.9 years; 68.9% male, apnea-hypopnea index 36.6 ± 28.4/h), 185 (7.8%) had no OSA and 2176 (92.2%) had OSA. Atherogenic dyslipidemia prevalence was high (57–66%) in OSA patients, and especially increased in severe OSA compared to other groups (p < 0.05). Though total and LDL-cholesterol did not differ between those with and without OSA, non-HDL-cholesterol (p = 0.020), and triglycerides (p = 0.001) were higher and HDL-cholesterol levels (p = 0.018) were lower in OSA patients than non-OSA. Non-HDL-cholesterol was significantly correlated with OSA severity (p < 0.001) and hypoxia parameters (p < 0.01), whereas LDL-cholesterol showed no correlation.ConclusionsAtherogenic dyslipidemia is highly prevalent and non-HDL-cholesterol levels are significantly increased, predominantly in severe OSA patients. Non-HDL-cholesterol but not LDL-cholesterol, is significantly correlated with OSA severity and hypoxia parameters. Therefore, it could be better to use non-HDL-cholesterol, which is a guideline recommended target of lipid therapy, as a marker of atherosclerotic cardiovascular risk in OSA patients.  相似文献   
13.
14.
Purpose/aim: To focus on current aspects of primary thyroid lymphoma (PTL), which is a rare clinical entity usually manifested by a rapidly growing mass in the neck that can cause pressure symptoms.

Materials and Methods: Relevant papers in PubMed published through June 2017 were selected to track updated information about PTL with an emphasis on diagnosis and novel therapeutic management.

Results: The most frequent cases include non-Hodgkin lymphoma derived from B-cells, mainly diffuse large B-cell lymphoma (DLBCL) followed by mucosa-associated lymphoid tissue (MALT) lymphoma or a mixed type. Other subtypes are less common. Lymphomas derived from T-cells and Hodgkin lymphomas are extremely rare. Hashimoto's autoimmune thyroiditis has been implicated as a risk factor for lymphoma. At the molecular level, the Wnt5a protein and its receptor Ror2 are involved in the course of the disease. Ultrasonography, fine needle aspiration (FNA) biopsy, and core or open biopsy combined with new diagnostic facilities contribute to an accurate diagnosis. An increased potential exists for a cure without the need for a radical surgical procedure. Modern chemoradiation therapy plus the monoclonal antibody rituximab, which acts against CD20, have limited the need for surgical interventions and provide an excellent outcome in most cases. However, some cases have resulted in treatment failure or recurrence.

Conclusions: A multidisciplinary approach must be used to define the management policy in each case. Future efforts by researchers are likely to be focused on the molecular level.  相似文献   

15.
16.
IntroductionMuch controversy exists over whether to perform lateral neck dissection (LND) on patients with papillary thyroid carcinoma (PTC). This study aimed to build predictive nomograms that could individually estimate lateral neck metastasis (LNM) risk and help determine follow up intensity.Patients and methodsUnifocal PTC patients who underwent LND between April 2012 and August 2014 were identified. Clinical and pathological variables were retrospectively evaluated using univariate and stepwise multivariate logistic regression analysis. Variables that had statistical significance in final multivariate logistic models were chosen to build nomograms, which were further corrected using the bootstrap resampling method.ResultsIn all, 505 PTC patients were eligible for analysis. Among these, 178 patients (35.2%) had lateral neck metastasis. Two nomograms were generated: nomogram (c) and nomogram (c + p). Nomogram (c) incorporated four clinical variables: age, tumor size, tumor site, and extrathyroidal extension (ETE). It had a good discriminative ability, with a C-index of 0.79 (bootstrap-corrected, 0.78). Nomogram (c + p) incorporated two clinical variables and two pathological variables: tumor size, tumor site, extranodal extension (ENE), and number of positive nodes in the central compartment. Nomogram (c + p) showed an excellent discriminative ability, with a C-index of 0.86 (bootstrap-corrected, 0.85).ConclusionTwo predictive nomograms were generated. Nomogram (c) is a clinical model, whereas nomogram (c + p) is a clinicopathological model. Each nomogram incorporates only four variables and can give an accurate estimate of LNM risk in unifocal PTC patients, which may assist clinicians in patient counseling and decision making regarding LND.  相似文献   
17.
背景与目的:甲状腺乳头状癌(papillary thyroid carcinoma,PTC)和桥本甲状腺炎(Hashimoto’s thyroiditis,HT)的发病率均呈上升趋势,两者之间的关系已成为目前研究的热点。探讨PTC和HT之间的关系。方法:回顾性分析2014—2015年期间在中国科学院大学附属肿瘤医院头颈肿瘤外科行甲状腺癌手术治疗的首诊患者306例,术后病理学检查均明确诊断为PTC,其中术后病理学确诊伴发HT者42例,比较伴发HT与未伴发HT患者的临床病理学特征。结果:PTC患者女性发病年龄高于男性(46.2岁 vs 41.9岁)。相较于与未伴发HT的PTC患者,伴发HT的患者中女性比例更高(93% vs77%),中央区淋巴结数目较多[(5.0±3.4)枚 vs (2.5±2.7)枚],术前促甲状腺激素(thyroid-stimulating hormone,TSH)水平较高[(3.28±1.91)μU/mL vs (2.12±1.29)μU/mL],术前抗甲状腺过氧化物酶抗体(thyroid peroxidaseantibody,TPOAb)阳性率较高(55% vs 14%),术前甲状腺球蛋白抗体(thyroglobulin antibodies,TgAb)阳性率较高(69% vs 13%)。发生中央区淋巴结转移的患者中,中央区淋巴结转移数目与中央区淋巴结总数显著相关(Pearson相关系数=0.582)。多因素logistic回归分析发现,男性、低龄、被膜侵犯是PTC患者中央区淋巴结转移的独立危险因素。结论:伴发HT对PTC患者的预后无显著影响。伴发HT的PTC患者TSH水平显著偏高,提示HT可能是PTC发病风险因素之一。中央区淋巴结转移数目与中央区淋巴结总数相关,推测PTC淋巴结转移可能与淋巴结炎症反应相关。  相似文献   
18.
19.
BackgroundWe sought to identify treatment disparities existing prior to publication of the 2015 American Thyroid Association Management Guidelines in order to identify patients with papillary thyroid cancer (PTC) at risk for receiving inadequate treatment.MethodsPatients diagnosed with PTC from 2011 to 2013 were identified using Surveillance, Epidemiology and End Results database. High-risk disease was defined as T4, N1, or M1. Chi-square tests compared characteristics of patients with and without high-risk disease and characteristics of high-risk patients who did and did not receive radioactive iodine ablation (RAI). Likelihoods of having high-risk disease, of receiving RAI, and of cause-specific death were calculated using regression analyses.ResultsSample included 32,229 individuals; 7894 (24.5%) had high-risk disease. Mean age was 50.0 years, 24,815 (77.0%) were female, and 21,318 (66.2%) were white. Odds of high-risk disease were greater among males (OR:2.04; 95% CI:1.92–2.16), Hispanics (OR:1.67; 95% CI:1.56–1.79) and Asians (OR:1.49; 95% CI:1.37–1.62), and uninsured (OR:1.24; 95% CI:1.07–1.43), and lower among patients ages 45–64 (OR:0.57; 95% CI:0.53–0.60), and ≥65 years (OR:0.54; 95% CI:0.50–0.59), and Blacks (OR:0.46; 95% CI:0.40–0.53). Most (69.3%) high-risk patients received RAI. Odds of receiving RAI were lower among patients age ≥65 years (OR:0.67; 95% CI:0.58–0.77), uninsured (OR:0.52; 95% CI:0.41–0.67), or with Medicaid (OR:0.58; 95% CI:0.50–0.69). RAI use reduced the risk of cause-specific mortality (HR:0.29; 95% CI:0.18–0.47).ConclusionKnowledge of these treatment disparities will allow recognition of groups at risk for high-risk disease and receiving inadequate treatment.  相似文献   
20.
Fine‐needle aspiration cytology using a novel ultrasound needle guidance system on the basis of standard needle magnetization was consecutively performed in 30 (15 in‐plane and 15 out‐of‐plane) suspicious thyroid nodules. Nondedicated, commercially available needles were used. The technical effectiveness and safety of the system were satisfying; system failures were observed in 2 cases. The needle tip could be (at least occasionally) visualized inside the thyroid nodule in 96%, and the subjective procedure ratings were excellent in 57%. The out‐of‐plane technique was significantly superior in both respects (P = .021 and .027, respectively). Standard needle magnetization ultrasound needle guidance was easy to apply and cost‐effective and has the potential to improve fine‐needle aspiration cytology performance.  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