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   1266篇
  免费   183篇
  国内免费   17篇
耳鼻咽喉   5篇
儿科学   26篇
妇产科学   31篇
基础医学   59篇
口腔科学   22篇
临床医学   111篇
内科学   353篇
皮肤病学   169篇
神经病学   71篇
特种医学   21篇
外科学   143篇
综合类   106篇
预防医学   75篇
眼科学   45篇
药学   153篇
  2篇
中国医学   42篇
肿瘤学   32篇
  2023年   17篇
  2022年   44篇
  2021年   79篇
  2020年   66篇
  2019年   83篇
  2018年   123篇
  2017年   94篇
  2016年   72篇
  2015年   57篇
  2014年   100篇
  2013年   83篇
  2012年   86篇
  2011年   80篇
  2010年   63篇
  2009年   63篇
  2008年   53篇
  2007年   46篇
  2006年   40篇
  2005年   19篇
  2004年   29篇
  2003年   26篇
  2002年   22篇
  2001年   17篇
  2000年   11篇
  1999年   8篇
  1998年   8篇
  1997年   4篇
  1996年   6篇
  1995年   1篇
  1994年   3篇
  1993年   5篇
  1992年   3篇
  1991年   2篇
  1990年   2篇
  1988年   1篇
  1987年   4篇
  1986年   5篇
  1985年   8篇
  1984年   8篇
  1983年   5篇
  1982年   5篇
  1981年   5篇
  1980年   1篇
  1979年   3篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
  1973年   1篇
排序方式: 共有1466条查询结果,搜索用时 15 毫秒
1.
在时域循环卷积运算实现反卷积方法的基础上,基于广义逆的概念提出了一种改进算法,该算法不仅可以有效地避开无谱逆问题,而且运算量增加较少,易于编程实现。  相似文献   
2.
目的研究17β-雌二醇(17β-E2)对子宫内膜异位症(内异症)患者在位子宫内膜间质细胞β-catenin mRNA和蛋白表达的影响,探讨Wnt/β-catenin信号通路在介导雌激素促进内异症发生发展的作用。方法体外分离培养内异症患者在位子宫内膜间质细胞。用不同浓度17β-E2处理子宫内膜间质细胞48 h;此后选用10-10mol/L 17β-E2处理子宫内膜间质细胞12、24和48 h,逆转录聚合酶链反应(RT-PCR)和免疫印迹法(Western blotting)检测17β-E2处理前后子宫内膜间质细胞β-catenin mRNA和蛋白的表达水平。同法分析雌激素受体拮抗剂ICI182,780(10-6mol/L)对17β-E2促进β-catenin mRNA和蛋白表达的影响。免疫组织化学染色观察17β-E2作用后β-catenin在子宫内膜间质细胞中的定位。结果17β-E2能明显促进内异症患者在位子宫内膜间质细胞β-catenin mRNA和蛋白的表达,并呈剂量和时间依赖性,于10-10mol/L作用48 h最明显。雌激素受体拮抗剂ICI182,780能明显抑制17β-E2对子宫内膜间质细胞β-catenin mRNA和蛋白的表达。免疫组织化学染色发现17β-E2能促进β-catenin在子宫内膜间质细胞核内的表达。结论雌激素可能通过激活Wnt/β-catenin信号通路促进内异症在位子宫内膜的异位种植。  相似文献   
3.
目的 观察川芎嗪对急性心肌梗死(AMI)患者梗死相关血管(mA)再通后心肌无复流(No.reflow,NR)现象的疗效。方法 首次急性sr段抬高心肌梗死(STEMI)患者,急诊经皮经腔冠状动脉介入(PCI)后,经单光子发射型计算机断层显像(SPECT)诊断为心肌NR者,随机分为治疗组(40例)和对照组(42例)。对照组接受常规治疗,治疗组在常规治疗基础上静脉给予川芎嗪注射液。分别于24h内(4—24h)及15d后(15—28d)复查SPECT,观察左室心肌灌注缺损积分(myocardium peffusion defect score,MPDS),左室射血分数(LVEF)、左室舒张末期容积(LVEDV)和左室收缩末期容积(LVESV)。结果 24h内及15d后,治疗组的MPDS均较PCI后即刻减低,其减低幅度均显著大于对照组(均P〈0.05);两组的LVESV和LVEDV均呈增加趋势,但治疗组LVESV和LVEDV的增加幅度显著低于对照组(均P〈0.05);15d后治疗组SPECT心肌NR的发生率显著低于对照组。结论 川芎嗪可显著改善心肌组织灌注,减轻心肌NR现象,从而缩小心肌坏死范围。抑制心室重构。  相似文献   
4.
A case of a male infant with several congenital anomalies combined with an interstitial deletion of the long arm of chromosome no. 5 is presented. The symptoms of the infant were compared to five previous reported cases with similar interstitial deletions in 5q.  相似文献   
5.
Numerous studies have shown that early coronary reperfusion is feasible in the setting of evolving acute myocardial infarction in man. While early reperfusion reduces myocardial infarct size, there are potentially deleterious consequences of reperfusion. The concept of "reperfusion injury", oxygen-free radical damage, no reflow phenomenon, and stunned myocardium are discussed.  相似文献   
6.
行腹膜外剖宫产术时,在侧脐韧带与中脐韧带之间进行操作,不切断腹壁任何韧带,用撕拉、钝性剥离的方法分离膀胱与腹膜,子宫切口连续缝合两层,并将宫颈前筋膜与子宫切口浅层一并连续缝合.该方法不仅缩短了手术时间,避免了新生儿Apgar's低评分、新生儿窒息的发生,而且维持了腹壁结构的完整性,可进一步降低术后各种近、远期并发症的发生率.  相似文献   
7.
ObjectiveTo analyse the profile of the persons and associations that participated in the course, quantify peer education activities and analyse their evolution.MethodA quantitative study using an analysis of the course records from 2009 to 2018 was designed for this purpose inside mihsalud program designed to promote health amongst persons in vulnerable situations in the city of Valencia (Spain). It offers a yearly training-action course of community health workers (CHW) that is attended by persons who have been proposed by associations. The associations were defined according to their population (immigrant, local or intercultural) and the CHWs according to gender, country of birth, year of course, association and continuity after training. Means and confidence intervals were calculated at 95% and a bivariate analysis was conducted in order to compare the activities that took place in 2009 to 2013 with those of 2014 to 2018. The time trends were analysed by applying linear regression models that included the different years studied as the dependent variable.Results201 CHW of 31 nationalities were trained, 81.6% (95% confidence interval [95% CI]: 75.5-86.7] were women. Eighty-two associations participated, 51.2% (95% CI: 39.9-62.4] worked with culturally diverse populations. Participation by associations (p = .017) and CHWs (p = .377) increased in a statistically significant manner over the years. After the course, 35.3% (95% CI: 28.7-42.4] of the CHWs continued to collaborate voluntarily in the associations.ConclusionsThe results of the CHW training-action course improve over time given that a significant increase in participation by associations and women can be seen, along with a greater number of activities completed during the training. One effect of this is that CHWs are contracted or carry out voluntary activities in the associations.  相似文献   
8.
9.
《Jornal de pediatria》2019,95(6):744-751
ObjectiveTo identify delays in the health care system experienced by children and adolescents and young adults (AYA; aged 0–29 years) with osteosarcoma and Ewing sarcoma using information from the Brazilian hospital-based cancer registries.MethodsPatient data were extracted from 161 Brazilian hospital-based cancer registries between 2007 and 2011. Hospital, diagnosis, and treatment delays were analyzed in patients without a previous histopathological diagnosis. Referral, hospital, and health care delays were calculated for patients with a previous histopathological diagnosis. The time interval was measured in days.ResultsThere was no difference between genders in overall delays. All delays increased at older ages. Patients without a previous histopathological diagnosis had the longest hospital delay when compared to patients with a previous histopathological diagnosis before first contact with the cancer center. Patients with Ewing sarcoma had longer referral and health care delays than those with osteosarcoma who had a previous histopathological diagnosis before first contact with the cancer center. The North and Northeast regions had the longest diagnosis delay, while the Northeast and Southeast regions had the longest treatment delay.ConclusionHealth care delay among patients with a previous diagnosis was longer, and was probably associated with the time taken for to referral to cancer centers. Patients without a previous histopathological diagnosis had longer hospital delays, which could be associated with possible difficulties regarding demand and high-cost procedures. Despite limitations, this study helps provide initial knowledge about the healthcare pathway delays for patients with bone cancer inside several Brazilian hospitals.  相似文献   
10.
Background: Hemangioma of the heart, presenting as a primary cardiac tumor is extremely rare. Methods: We present a 20-year-old male with a cardiac tumor which was incidentally discovered during routine clinical examination. Results: Echocardiography showed a large intramyocardial mass attached to the left ventricle, close to the apex. A tumor was shown near the apex of the left ventricle by Cardiac CT. We performed a total resection surgery of the tumor one week after admission and the patient recovered well and discharged from hospital 7 d after surgery. Conclusion: The pathological diagnosis was primary cardiac capillary hemangioma. No tumor recurrence was shown by echocardiography after 20 months follow-up visits.  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