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   90149篇
  免费   3833篇
  国内免费   1182篇
耳鼻咽喉   522篇
儿科学   1430篇
妇产科学   980篇
基础医学   11125篇
口腔科学   3823篇
临床医学   7161篇
内科学   17863篇
皮肤病学   1843篇
神经病学   6220篇
特种医学   2455篇
外国民族医学   5篇
外科学   14251篇
综合类   6081篇
现状与发展   3篇
一般理论   5篇
预防医学   7224篇
眼科学   1666篇
药学   5995篇
  21篇
中国医学   2995篇
肿瘤学   3496篇
  2023年   1272篇
  2022年   2199篇
  2021年   3632篇
  2020年   2548篇
  2019年   6499篇
  2018年   6642篇
  2017年   4234篇
  2016年   1574篇
  2015年   1545篇
  2014年   3099篇
  2013年   3099篇
  2012年   2223篇
  2011年   2632篇
  2010年   2216篇
  2009年   1885篇
  2008年   2036篇
  2007年   1981篇
  2006年   1752篇
  2005年   1494篇
  2004年   1313篇
  2003年   1368篇
  2002年   990篇
  2001年   969篇
  2000年   844篇
  1999年   791篇
  1998年   618篇
  1997年   637篇
  1996年   524篇
  1995年   518篇
  1994年   471篇
  1993年   409篇
  1992年   377篇
  1991年   339篇
  1990年   281篇
  1989年   259篇
  1988年   246篇
  1987年   201篇
  1985年   3021篇
  1984年   3545篇
  1983年   2960篇
  1982年   3451篇
  1981年   3134篇
  1980年   2590篇
  1979年   2561篇
  1978年   2092篇
  1977年   1574篇
  1976年   2021篇
  1975年   1524篇
  1974年   1330篇
  1973年   1279篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
临床医师处方抗菌药物前需思考的几个问题   总被引:20,自引:0,他引:20  
吴安华 《中国医院》2004,8(8):19-22
2001年和2003年卫生部全国医院感染监测网调查结果均显示,医院横断面抗菌药物的平均使用率在54%以上,联合用药较为普遍.国内监测结果也表明细菌耐药性日益严重.针对上述问题,提出临床医师在面对病人开处方抗菌药物之前,须思考的问题:是否有使用抗菌药物的适用症?是否了解选用的抗菌药物,选用何种药物?是否有联合使用抗菌药物的指征?采用何种给药途径、给药剂量、给药时间?是否属于特殊宿主或针对特殊病原体的感染使用抗菌药物?密切观察抗菌药物治疗是否有效?针对局部感染是否需要穿刺或外科手术引流病灶?是否已出现抗菌药物的不良反应?是否存在药物相互作用?是否存在不合理使用抗菌药物情况?并且针对每个问题提出了建议.  相似文献   
102.
During T cell development, thymocytes which are tolerant to self-peptides but reactive to foreign peptides are selected. The current model for thymocyte selection proposes that self-peptide–major histocompatibility complex (MHC) complexes that bind the T cell receptor with low affinity will promote positive selection while those with high affinity will result in negative selection. Upon thymocyte maturation, such low affinity self-peptide–MHC ligands no longer provoke a response, but foreign peptides can incidentally be high affinity ligands and can therefore stimulate T cells. For this model to work, thymocytes must be more sensitive to ligand than mature T cells. Contrary to this expectation, several groups have shown that thymocytes are less responsive than mature T cells to anti-T cell receptor for antigen (TCR)/CD3 mAb stimulation. Additionally, the lower TCR levels on thymocytes, compared with T cells, would potentially correlate with decreased thymocyte sensitivity. Here we compared preselection thymocytes and mature T cells for early activation events in response to peptide–MHC ligands. Remarkably, the preselection thymocytes were more responsive than mature T cells when stimulated with low affinity peptide variants, while both populations responded equally well to the antigenic peptide. This directly demonstrates the increased sensitivity of thymocytes compared with T cells for TCR engagement by peptide–MHC complexes.  相似文献   
103.
对28例Graves病的可溶性白介素2受体(sIL2R)和各种甲状腺激素以及甲状腺自身抗体治疗前后比较,并进行逐步回归,结果表明:治疗后Graves病患者除TSH外,各种甲状腺激素及甲状腺自身抗体显著降低(P<001),并对sIL2R的上升与下降呈显著相关。  相似文献   
104.
105.
In patients with allergic asthma and rhinitis high numbers of hypodense eosinophils (HE) have been demonstrated. In a previous study we reported that asthmatic and healthy children had more HE than their adult counterparts. We assumed that this might, in part, he due to the presence of immature eosinophils in children. To distinguish between immature and activated eosinophils, determination of eosinophil cationic protein (ECP) might be interesting as it is known that high serum levels of ECP are associated with increased activation of eosinophiis. In this study we determined (he levels of ECP in scrum in asthmatic and healthy children and adults trying to distinguish activated from immature eosinophils. We found that ECP levels were not increased in children (healthy and asthmatic) compared to adults (healthy and asthmatic). This supports the hypothesis that increased numbers of HE in childhood are, at least in part, immature eosinophils. Nevertheless, we could confirm that inflammation was present in children because soluble interleukin-2-receptor (slL-2R), a marker of lymphocyte activation, was higher in asthmatic children as compared to healthy children. IL-6, a marker of macrophage/monocyte activation, was not different in the different patient groups. We conclude that although signs of inflammation are present in childhood asthma, the increased numbers of HE in children are in part due to the presence of immature eosinophils.  相似文献   
106.
We assessed the prevalence of Parkinson's disease in Cantalejo, Spain. In 1994, we screened 1,579 persons (age > or = 40 years) using a high-sensitivity method. Cases fulfilling established clinical criteria were followed for a minimum of 3 years. Prevalences were compared with those from other door-to-door surveys. We detected 27 individuals with parkinsonism, 20 of whom had Parkinson's disease. The prevalence of Parkinson's disease increased with age and, when age-adjusted to European standards, was 9.01 per 1,000 (age 40 years and over; 10.78 in men and 5.23 in women). Of the 11 men, three were in Hoehn & Yahr grades III-IV, but six of the nine women were more severely affected. Overall, we found 18 newly diagnosed cases of parkinsonism, 13 of which were Parkinson's disease, and the majority of which were in men aged 80 years or older with a mean duration of illness of 5 years. Our prevalence figures are the highest reported, apparently because of the inclusion of several very elderly men. Parkinson's disease in Cantalejo is less severe in men than in women, particularly in those newly diagnosed. Despite the low numbers, the high prevalence and sex-related pattern are unexplained but they probably relate to the high sensitivity of the screening method.  相似文献   
107.
王有谦  荆建杰  李俊  杜曾 《实用医技杂志》2005,12(24):3651-3651
我科于1999年10月以来,对各种原因引起的脑出血(出血量≥30 ml)的患者采用贾保祥[1]教授研制的微创颅内血肿清除术进行治疗,取得了良好效果。现报告如下。1临床资料1.1一般资料本组65例,男38例,女27例,发病年龄32岁-83岁,平均年龄56.2岁。其中高血压引起的脑出血63例,急性硬膜下血肿2例,超早期(发病7 h内)就诊28例,早期(发病7 h~3 d)就诊35例,延期(发病3 d以上)2例。1.2临床表现大部分患者发病早期均有头痛或头晕,其中呕吐52例,有高血压史者59例,有头部外伤史2例。神志清醒者17例,昏迷48例,其中深昏迷18例,中度昏迷21例,浅昏迷9例。61例偏瘫…  相似文献   
108.
Zusammenfassung Die Pankreaskopfresektion in der Modifikation nach Traverso-Longmire, mit Erhaltung eines funktionierenden Pylorus, hat gegenüber der Kausch-Whipple-Operation die Vorteile, daß Anastomosenulzera vermieden werden und daß die Patienten postoperativ eine bessere und schnellere Gewichtszunahme haben. Indikationen waren bisher die Papillenkarzinome und periampulare Tumoren. Bei den Adenokarzinomen lassen sich mit der Pyloruserhaltung gleich gute Überlebensraten erzielen. Unsere Ergebnisse von 56 Pyloruserhaltungen, davon 32 beim duktalen Karzinom und 28 Kausch-Whipple-Operationen in den Jahren von 1985–1993, belegen gleiche Überlebensraten, wie dies bereits für das Papillenkarzinom gezeigt werden konnte. Die Überlebenskurven zeigen, daß die Radikalität nicht von der Magenteilentfernung, sondern von der Resektion an den posterioren und retroperitonealen Resektionsrändern abhängt.
Current indications for pylorus preservation in duodenopancreatic head resection in malignancies
The Whipple procedure has been improved by preservation of a functioning pylorus. A functioning pylorus is important because marginal ulceration is avoided and, compared to the standard Whipple procedure with gastric resection, more patients can gain weight postoperatively. The most common indications are carcinomas of ampulla of Vater and periampullary tumors. In patients with pancreatic adenocarcinoma the pylorus-preserving variety results in equal or better survival rates. In 56 patients with pylorus preservation, 32 with ductal carcinoma, and 28 with Kausch-Whipple between 1985 and 1993, our results showed slightly better survival rates and better post-operative nutrition. The weakest aspect of the radical resection addresses the retroperitoneal margin of the pancreas head and not the gastric resection.
  相似文献   
109.
Arthroscopy has a valuable role in the treatment of elbow arthritis in the athletic population. General arthroscopicdebridement techniques used in the treatment of arthritis in other joints are quite valuable. Arthroscopic modifications of open techniques unique to the elbow, such as ulnohumeral arthroplasty, also are useful. As in other joints, the benefits of arthroscopic treatment of elbow arthritis may be temporary. Proper patient selection and attention to technical detail are critical in this population.  相似文献   
110.
Dr  N. Sukcharoen  J. Keith 《Andrologia》1996,28(4):203-210
Summary. The present study was carried out to investigate the predictive value of the percentage of sperm motility after 24-h incubation and sperm survival ratio from semen and inseminated sperm suspension using grading of motility by WHO criteria with respect to the fertilization of oocytes in vitro. A total of 789 oocytes from 85 cases were inseminated and the mean fertilization rate obtained was 72.5%. There was no significant correlation between all of the sperm motility results with fertilization rate in vitro. All sperm motility results were not significantly different between the non-fertilizing group and the fertilizing group and also between the group of fertilization rate ≤ 25th percentile (fertilization rate ≤62.5%) and the group of fertilization rate >62.5%. However, the initial percentage of rapid progressive sperm motility and progressive motility in semen and inseminated sperm suspension at 24 h gave significant differences between the group of fertilization ≤ 50th percentile (fertilization rate ≤80%) and the group of fertilization rate >80%. Overall accuracy using these parameters for prediction of fertilization rate >80% was only about 60%. In conclusion, the percentage of sperm motility at 24 h and sperm survival ratio in both semen and inseminated sperm suspension have no practical value in predicting fertilization rate in vitro. Moreover, detailed motility grading cannot improve the predictivity of these sperm motility parameters.  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