全文获取类型
收费全文 | 40666篇 |
免费 | 2994篇 |
国内免费 | 384篇 |
专业分类
耳鼻咽喉 | 61篇 |
儿科学 | 556篇 |
妇产科学 | 761篇 |
基础医学 | 3421篇 |
口腔科学 | 268篇 |
临床医学 | 4568篇 |
内科学 | 1475篇 |
皮肤病学 | 298篇 |
神经病学 | 227篇 |
特种医学 | 2770篇 |
外科学 | 8534篇 |
综合类 | 5389篇 |
预防医学 | 1882篇 |
眼科学 | 61篇 |
药学 | 2617篇 |
12篇 | |
中国医学 | 824篇 |
肿瘤学 | 10320篇 |
出版年
2024年 | 40篇 |
2023年 | 407篇 |
2022年 | 997篇 |
2021年 | 1478篇 |
2020年 | 1358篇 |
2019年 | 1065篇 |
2018年 | 1300篇 |
2017年 | 1289篇 |
2016年 | 1381篇 |
2015年 | 1430篇 |
2014年 | 3085篇 |
2013年 | 2746篇 |
2012年 | 2633篇 |
2011年 | 2933篇 |
2010年 | 2312篇 |
2009年 | 2391篇 |
2008年 | 2495篇 |
2007年 | 2415篇 |
2006年 | 2000篇 |
2005年 | 1568篇 |
2004年 | 1293篇 |
2003年 | 1042篇 |
2002年 | 863篇 |
2001年 | 764篇 |
2000年 | 662篇 |
1999年 | 547篇 |
1998年 | 504篇 |
1997年 | 468篇 |
1996年 | 339篇 |
1995年 | 336篇 |
1994年 | 297篇 |
1993年 | 212篇 |
1992年 | 193篇 |
1991年 | 160篇 |
1990年 | 110篇 |
1989年 | 150篇 |
1988年 | 105篇 |
1987年 | 86篇 |
1986年 | 65篇 |
1985年 | 105篇 |
1984年 | 62篇 |
1983年 | 38篇 |
1982年 | 69篇 |
1981年 | 68篇 |
1980年 | 57篇 |
1979年 | 38篇 |
1978年 | 23篇 |
1977年 | 23篇 |
1976年 | 15篇 |
1975年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Maggie L. Westfal David C. Chang Cassandra M. Kelleher 《Journal of pediatric surgery》2019,54(1):140-144
Purpose
The purpose of this study was to evaluate trends in demographics and outcomes of pediatric breast cancer in a United States population-based cohort.Methods
The Surveillance, Epidemiology, and End Results (SEER) database was utilized to identify all pediatric patients with malignant breast tumors between 1973 and 2014. Analysis was performed using Stata Statistical Software version 13.1. Associations between categorical variables were made using X2 test. Log-rank test was used for univariate survival analysis. Kaplan–Meier analysis investigated five-year survival rates across several variables. Adjusted analysis was performed using a Cox Proportional-Hazards regression.Results
134 patients with breast malignancies were identified. Carcinoma was the most prevalent histology (48.5%), followed by fibroepithelial tumors (FETs) (35.1%), and sarcoma (14.2%). FETs were twice as common in black compared to nonblack patients (56.3% vs. 29.0%, p?<?0.01). Analyzing histology by stage revealed that 100% of FETs were early stage disease (p?<?0.0001). 46.7% of the tumors tested were ER/PR negative, more than twice as many compared to the published adult estimate of 20.0%. Unadjusted survival analysis revealed worse survival for patients with adenocarcinoma/sarcomas, advanced stage, and high grade disease, without a survival difference between races.Conclusion
Breast cancer remains a rare malignancy among pediatric patients. Although black patients were found to have more noncarcinomatous tumors with less advanced disease, this did not confer a survival advantage.Type of study
Retrospective cohort study.Level of evidence
Level III. 相似文献52.
53.
Eitaro Ito Akihiro Takai Yoshinori Imai Hiromi Otani Yoshihiro Onishi Yosuke Yamamoto Kohei Ogawa Taiji Tohyama Shunichi Fukuhara Yasutsugu Takada 《Surgery》2019,165(2):353-359
Background
Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life.Methods
This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time.Results
A total of 58 patients in the single-incision group and 53 in the 4-port group (n?=?111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval –0.4 to 3.2, P?=?.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy.Conclusion
Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy. 相似文献54.
《Journal of vascular and interventional radiology : JVIR》2020,31(4):635-643
PurposeThis study evaluated the factors affecting contralateral and ipsilateral recurrent deep vein thrombosis (DVT) after iliac vein stent placement in patients with iliac vein compression syndrome (IVCS).Materials and MethodsData from 130 patients (95 female patients) who underwent catheter-directed thrombolysis and stent placement for IVCS with left lower leg thrombosis at a single institution were retrospectively analyzed. Mean patient age was 69.0 ± 14.0 years old. Median follow-up was 14 months (range, 3–164 months). Anticoagulation therapy was prescribed for 6 months, followed by lifelong antiplatelet therapy. Multivariate logistic regression analysis was performed to evaluate the factors affecting the development of contralateral and ipsilateral recurrent DVT.ResultsSeven patients (5.4%) developed contralateral DVT (median, 26 months; range, 2–61 months), and 11 patients (8.5%) developed ipsilateral DVT (median, 1 month; range, 0–53 months). Stent location (odds ratio [OR], 11.564; 95% confidence interval [CI], 1.159–115.417) and in-stent thrombosis during follow-up (OR, 15.142; 95% CI, 1.406–163.119) were predictors of recurrent contralateral DVT. Thrombophilia (OR, 47.560; 95% CI, 2.369–954.711), remaining inferior vena cava filter (OR, 30.552; 95% CI, 3.495–267.122), and in-stent thrombosis during follow-up (OR, 82.057; 95% CI, 2.915–2309.848) were predictors of ipsilateral DVT.ConclusionsContralateral DVT occurs late and is associated with extension of the iliac vein stent to the inferior vena cava and in-stent thrombosis. Ipsilateral DVT occurs relatively early and is associated with thrombophilia, remaining inferior vena cava filter, and in-stent thrombosis. 相似文献
55.
目的 探讨NRP-1单克隆抗体(NRP-1 MAb)的特异性,以及不同剂量的NRP-1 MAb治疗乳腺癌裸鼠移植瘤的疗效。方法 Western blot和共聚焦免疫荧光法检测NRP-1 MAb是否识别MCF7细胞上NRP-1蛋白。将MCF7细胞接种于BALB/c裸鼠皮下建立乳腺癌细胞移植瘤模型,并进行瘤组织传代。传代的肿瘤体积生长至300~500 mm3时,随机分为对照组、NRP-1 MAb低剂量组、中剂量组和高剂量组,每组6只,给药7次。观察荷瘤裸鼠一般状况,测量瘤体大小及裸鼠体重。实验结束时剥离瘤体称重,提取组织蛋白,Western blot检测组织中VEGF蛋白和NRP-1蛋白的表达量。结果 NRP-1MAb成功识别MCF7细胞上的NRP-1蛋白;NRP-1 MAb能够有效抑制MCF7细胞裸鼠移植瘤的生长,低剂量组(1 mg/kg)抑瘤率为47.01%,中剂量组(5 mg/kg)抑瘤率为65.70%,高剂量组(10 mg/kg)抑瘤率为69.19%。。结论 NRP-1 MAb能够识别并有效结合MCF7细胞膜上的NRP-1蛋白,且可抑制MCF7细胞移植瘤的生长,NRP-1 MAb抑制移植瘤的增长可能与下调NRP-1和VEGF表达有关。 相似文献
56.
目的探讨CT动态增强对鉴别肾上腺乏脂肪腺瘤与肾上腺结节样增生的价值。方法回顾性分析经手术病理证实的12例肾上腺乏脂肪腺瘤和27例肾上腺结节样增生患者的病例资料,统计两组病例各期增强CT值,利用公式灌注值P=CT静脉期-CT平扫期、廓清值C=CT静脉期-CT延迟期、绝对廓清灌注指数APC=(C/P)×100%及相对廓清灌注指数RAPC=(C/CT静脉期)×100%得到相关参数,并通过绘制受试者工作特征曲线,鉴别两者的最佳价值。结果肾上腺乏脂肪腺瘤直径较结节样增生更大;肾上腺乏脂肪腺瘤病灶各期CT值均明显高于结节样增生,且两者灌注值P、廓清值C、APC及RAPC有明显的统计学差异。年龄、性别、高血压、病灶位置、对侧肾上腺萎缩及动脉期CT值对鉴别两者无显著意义。结论CT动态增强扫描有助于鉴别肾上腺乏脂肪腺瘤和肾上腺结节样增生。 相似文献
57.
BackgroundMedication adherence is crucial for improving clinical outcomes in the treatment of patients. We evaluate the effect of short message service (SMS) reminder on medication adherence and serum hormones in patients with breast cancer on aromatase inhibitors.MethodsAn open-label, multi-centre, prospective randomised controlled trial of SMS versus Standard Care was conducted. Medication adherence was assessed via self-report using the Simplified Medication Adherence Questionnaire at baseline, 6 month, and 1 year. Androstenedione, estradiol, and estrone were measured at baseline and 1 year. The χ2 test and mixed effects logistic regression was performed to compare medication adherence between groups. Difference in androstenedione and estrone levels were assessed using analysis of covariance, whereas χ2 test and logistic regression was used for estradiol. Analysis was based on intention-to-treat.ResultsA total of 244 patients were randomised to receive weekly SMS reminder (n = 123) or Standard Care (n = 121) between May 2015 and December 2018. The odds of adherence was higher at 6-month in SMS (OR = 1.78, 95% CI 1.04–3.05, p = 0.034), and not significantly different at 1-year (OR = 1.15, 95% CI: 0.67–1.96 p = 0.617). Mixed effects logistic regression analysis showed higher odds of adherence in SMS over the 1-year period (OR = 2.35, 95% CI: 1.01–5.49, p = 0.048). There was no difference in serum hormone levels between groups.ConclusionSMS reminder improved medication adherence in the short-term but had no effect on serum hormones levels in the longer term. Future studies could investigate the use of tailored SMS intervention according to patient preference to improve its sustainability. 相似文献
58.
ObjectiveTo investigate long-term health-related quality of life (HRQoL) changes over time in younger compared to older disease-free breast cancer survivors who participated in a prospective randomized exercise trial.MethodsSurvivors (aged 35–68 years) were randomized to a 12-month exercise trial after adjuvant treatment and followed up for ten years. HRQoL was assessed with the generic 15D instrument during follow-up and the younger (baseline age ≤ 50) and older (age >50) survivors’ HRQoL was compared to that of the age-matched general female population (n = 892). The analysis included 342 survivors.ResultsThe decline of HRQoL compared to the population was steeper and recovery slower in the younger survivors (p for interaction < 0.001). The impairment was also larger among the younger survivors (p = 0.027) whose mean HRQoL deteriorated for three years after treatment and started to slowly improve thereafter but still remained below the population level after ten years (difference −0.017, 95% CI: −0.031 to −0.004). The older survivors’ mean HRQoL gradually approached the population level during the first five years but also remained below it at ten years (difference −0.019, 95% CI: −0.031 to −0.007). The largest differences were on the dimensions of sleeping and sexual activity, on which both age groups remained below the population level throughout the follow-up.ConclusionsHRQoL developed differently in younger and older survivors both regarding the most affected dimensions of HRQoL and the timing of the changes during follow-up. HRQoL of both age groups remained below the population level even ten years after treatment. 相似文献
59.
BackgroundApproximately 7% of breast cancers are diagnosed in women under 40. Question of subsequent fertility has become fundamental. We aimed to evaluate the rate of fertility preservation (FP) by oocyte retrieval (OR) after ovarian stimulation in patients of childbearing age, managed for breast cancer with adjuvant chemotherapy in France, reuse rate of frozen gametes and live births rate (LBR) after treatment.MethodsWe included 15,774 women between 18 and 40 years old, managed by surgery and adjuvant chemotherapy for breast cancer, between January 2011 and December 2020 from a French health registry. Patients with OR after breast surgery and before chemotherapy were considered as FP group; those with no OR as no FP group. To compare LBR with French population independently of age, we calculated Standardized Incidence Rates (SIR) of live births using indirect standardization method.ResultsFP rate increased gradually since 2011, reaching 17% in 2019. A decrease in use was observed in 2020 (13,9%). Among patients with at least 2 years of follow-up, gamete reuse rate was 5,6%. Births after cancer were mostly from spontaneous pregnancies. Among patients with at least 3 years of follow-up, LBR was 19,6% in FP group, 3,9% in second group. SIR of live births was of 1,05 (95% CI = 0.91–1.19) and 0.33 (95% CI = 0.30–0.36) in FP and no FP group respectively.ConclusionOncofertility activity increased until 2019 in France, reaching 17%. Gamete reuse rate was low. Births resulted mainly from spontaneous pregnancies. SIR of live births was lower in no FP group. 相似文献
60.
目的:研究体外缺氧对乳腺癌细胞系MCF7浸润能力及其细胞表面黏附分子E-cadherin和细胞骨架蛋白犤细胞角蛋白(cytokeratin)、波形蛋白(vimentin)犦表达的影响。方法:模拟体外缺氧环境,观察缺氧对乳腺癌细胞MCF7浸润穿透Matrigel的能力;以及采用半定量RT-PCR检测细胞表面黏附分子E-cadherin和cytokeratin、vimentin表达情况。结果:缺氧状态下MCF7细胞的浸润能力明显增强;且在缺氧条件下E-cadherin基因表达下降、cytokeratin、vimentin基因表达升高。结论:缺氧状态下MCF7细胞转移能力和其表面的E-cadherin基因、cytokeratin、vimentin基因表达存在一定关系。 相似文献