全文获取类型
收费全文 | 621篇 |
免费 | 62篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 42篇 |
妇产科学 | 9篇 |
基础医学 | 98篇 |
口腔科学 | 12篇 |
临床医学 | 75篇 |
内科学 | 66篇 |
皮肤病学 | 12篇 |
神经病学 | 56篇 |
特种医学 | 47篇 |
外科学 | 49篇 |
综合类 | 29篇 |
预防医学 | 36篇 |
眼科学 | 47篇 |
药学 | 45篇 |
中国医学 | 4篇 |
肿瘤学 | 37篇 |
出版年
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 34篇 |
2013年 | 31篇 |
2012年 | 33篇 |
2011年 | 28篇 |
2010年 | 29篇 |
2009年 | 25篇 |
2008年 | 19篇 |
2007年 | 25篇 |
2006年 | 25篇 |
2005年 | 25篇 |
2004年 | 20篇 |
2003年 | 24篇 |
2002年 | 21篇 |
2001年 | 10篇 |
2000年 | 20篇 |
1999年 | 15篇 |
1998年 | 17篇 |
1997年 | 20篇 |
1996年 | 16篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 12篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 3篇 |
1988年 | 10篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1981年 | 5篇 |
1978年 | 10篇 |
1977年 | 4篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1969年 | 3篇 |
1966年 | 4篇 |
1956年 | 3篇 |
1954年 | 2篇 |
1952年 | 16篇 |
1951年 | 23篇 |
1950年 | 2篇 |
排序方式: 共有684条查询结果,搜索用时 343 毫秒
71.
目的通过基因芯片筛选同真皮间充质干细胞相关的创伤修复差异表达基因。方法利用贴壁生长的特性分离大鼠真皮间充质干细胞,用Hpure提取伤口液刺激前后dMSCs和创伤前后大鼠皮肤组织中总RNA。PCR扩增已构建抑制消减杂交差异表达文库中485个克隆的插入片断,送北京博奥制作基因芯片。提取的RNA反转录后分别同芯片杂交,找出在细胞水平和组织水平同时高表达的克隆。将这些克隆测序,进行生物信息学分析。结果分离的大鼠真皮间充质干细胞呈纺锤形,在体外显示多向分化潜能。抽提伤口液刺激前后dMSCs和创伤前后大鼠皮肤组织中总RNA,反转录后和基因芯片杂交,发现可能同创伤愈合相关的13条基因,其中热休克蛋白70(HSP70),基质金属蛋白酶3(MMP3),白细胞蛋白酶抑制因子(SLPI)等可能在创伤愈合中有重要意义。结论抑制消减杂交和基因芯片结合是筛选差异表达基因的一种有效方法。伤口液刺激前后dMSCs中差异表达基因的发现能为从基因水平探讨dMSCs参与创伤愈合的分子机制提供新的研究靶点。 相似文献
72.
HT Lam ; SO Schweitzer ; L Petz ; MH Kanter ; DA Bernstein ; S Brauer ; DV Pascual ; BA Myhre ; IA Shulman ; GW Sun 《Transfusion》1997,37(6):577-584
BACKGROUND: The purpose of this study was to search for a more effective transfusion-monitoring system than the existing system of retrospective peer review. STUDY DESIGN AND METHODS: This research used a study-control, preintervention and postintervention design, to evaluate the effectiveness of a prospective physician self-audit transfusion-monitoring system that functioned without the direct involvement of transfusion service physicians. This research also evaluated the effectiveness of issuing to physicians a memo with transfusion guidelines. Three process indicators were used to assess physician behavior at various stages of the blood-ordering process: 1) the number of crossmatches ordered per admission, 2) the transfusion-to- crossmatch ratio, and 3) the number of blood units returned to the laboratory after physician self-auditing. The study used two outcome indicators to reflect overall blood utilization: 1) the percentage of patients who received red cell transfusions and 2) the number of blood units transfused per recipient each month. RESULTS: The prospective physician self-audit system implemented at the study hospital did not reverse physician transfusion decisions, and the process of issuing to physicians a memo with transfusion guidelines at the control hospital failed to reduce blood usage. However, a transient reduction in blood utilization was observed at the study hospital. CONCLUSION: The reduction was hypothesized to be due to a Hawthorne effect, in which observed behavior is affected by the subject's awareness of the research study. 相似文献
73.
BACKGROUND: Before 1987, fewer than 50 patients per year at the authors' laboratory had a positive antibody detection test due to antepartum Rhesus immunoprophylaxis. However, after 1987, a marked increase was observed in the number of patients who had received Rh immune globulin (RhIG) during pregnancy as part of routine antepartum Rh immunoprophylaxis. In anticipation that an increased use of RhIG during pregnancy would increase the number of patients in whom anti-D was detected by this laboratory, a protocol was developed to abbreviate the process required to identify anti-D. Although this protocol was adopted primarily to address an anticipated increase in antenatal RhIG usage in women, it was also applied to alloimmunized Rh-negative males. STUDY DESIGN AND METHODS: When an Rh-negative patient (male or female) had a reactive screening test for unexpected antibodies and met certain other criteria, the patient's serum was tested with a three-vial set of Rh-negative reagent red cells (Rh-negative screening RBCs), instead of with panels of typed RBCs (panel RBCs), for the identification of anti- D or the detection of non-D antibodies. If the serum under test did not agglutinate or hemolyze Rh-negative screening RBCs, anti-D was identified and no further testing was performed. If the serum agglutinated or hemolyzed Rh-negative screening RBCs, conventional testing with panel RBCs was done to determine the antibody specificity. RESULTS: Rh-negative patients (n = 1174) who had reactive screening tests for unexpected antibodies were tested with Rh-negative screening RBCs; 1079 were found to have anti-D as a single antibody. Seven of these patients subsequently developed a non-D alloantibody, after transfusion or pregnancy, and one patient had anti-C that escaped detection at the time of initial testing with Rh-negative RBCs (a false- negative result). Ninety-two patients had anti-D in combination with a non-D antibody, and three patients had a non-D antibody but not anti-D. Use of the anti-D identification protocol actually reduced the laboratory workload by 176 College of American Pathologists workload units per month, in spite of a marked increase in the number of patients in whom anti-D was detected. No hemolytic transfusion reaction was attributed to the abbreviation of anti-D identification. CONCLUSION: The identification of anti-D may be abbreviated without jeopardizing patient safety. Such a protocol can reduce laboratory workload and might be particularly appealing to health care facilities that perform antibody detection testing on large numbers of Rh-negative pregnant women, especially if antepartum RhIG is administered routinely. 相似文献
74.
L. A. Pierce W. O. Tarnow-Mordi I. A. Cree 《International Journal of Clinical & Laboratory Research》1996,26(2):112-118
Intact phagocyte function is a pre-requisite for successful defence against infection, but paradoxically, these cells may
also play a major role in the pathogenesis of the infant respiratory distress syndrome. Phagocyte function is known to be
deficient in pre-term infants, who are at risk of infection as a result, but these infants are also at risk of respiratory
distress syndrome as a result of surfactant deficiency. Despite this, few longitudinal studies of phagocyte function have
been performed in pre-term infants. We have used lucigenin-enhanced chemiluminescence to examine the respiratory burst of
mixed samples containing polymorphonuclear leucocytes and monocytes of 100 pre-term infants at 48- to 72-h intervals during
their admission to a neonatal care unit. Increased polymorphonuclear leucocyte chemiluminescence was associated with respiratory
distress syndrome and the use of intermittent positive pressure ventilation. Multiple linear regression analysis revealed
a slight, but significant depression of chemiluminescence in association with the use of gentamicin and penicillin when stronger
influencing factors such as the presence of respiratory distress syndrome were taken into consideration. Measurement of phagocyte
function by sensitive luminescence assays requires very little blood and may be useful in pre-term infants to follow the severity
of respiratory distress syndrome. However, it is probable that other factors such as antioxidant capacity also have an important
influence on the degree of tissue damage. 相似文献
75.
Functional dependence after hip fracture 总被引:1,自引:0,他引:1
Cree M Carriere KC Soskolne CL Suarez-Almazor M 《American journal of physical medicine & rehabilitation / Association of Academic Physiatrists》2001,80(10):736-743
OBJECTIVES: To identify patients at high risk of functional dependence and examine the progression of disability after a hip fracture. DESIGN: This was a population-based prospective inception cohort study of all patients aged 65+ yr who fractured a hip between July 1996 and August 1997. Demographic, socioeconomic, social support, and health status information was assessed in the hospital and 3 mo postfracture. RESULTS: The analysis included 367 patients. Almost all patients with cognitive impairment were functionally dependent postfracture, with new disabilities frequently occurring in transferring. Among patients of high mental status, increased risk of functional dependence was associated with advanced age, more co-morbidities, hip pain, poor self-rated health, and previous employment in a prestigeous occupation. Bathing disability was most likely in those who functioned independently prefracture; a disability in dressing was most common otherwise. CONCLUSION: Hip pain is amenable to treatment and may improve chances of functional recovery. Patients can be assisted in regaining prefracture function if they are targeted for rehabilitation on the basis of mental status. The focus should be on bathing and dressing among patients of high cognition and transferring among those patients with mental impairment. 相似文献
76.
Sexual Dimorphism of Digit‐Length Ratio in a Viviparous Lizard: Influence of Age,but not Preservation State or Sex of Interuterine Twin 下载免费PDF全文
Nikita Woodhead Kelly M. Hare Alison Cree 《Anatomical record (Hoboken, N.J. : 2007)》2018,301(7):1169-1178
The existence of sex differences in digit‐length ratio (especially between the second and fourth digits, 2D:4D) is well established for humans from fetal life onwards, and has been linked with later performance. In rodents, the ratio is affected prenatally by exposure to androgens and estrogens, with some research suggesting an influence from sex of the neighbouring intrauterine fetus. However, the ubiquity and ontogenetic development of sexual dimorphism in digit ratios is not well established among wild amniotes. We report the first digit ratios for a gekkotan lizard, representing a speciose lineage in which viviparity has evolved independently from mammals and other reptiles. For the gecko Woodworthia “Otago/Southland”, in which up to two embryos develop in separate uteri, we found: (1) significant sexual dimorphism in adults in 2D:3D of the right hindlimb only (larger in males), but not in 2D:4D for any limb; (2) no dimorphism in ratios for young juveniles, with no influence of sex of the interuterine twin, and no relationship with sprint speed; (3) in preserved tissues of the same juveniles, no sexual dimorphism in ratios, but a change in relative lengths of some digits with preservation. The ontogenetic pattern might be explained by altered sex–steroid exposure at the transition to adulthood rather than during prenatal development. Our results support a phylogenetic hypothesis that sauropsids (birds and reptiles) differ from mammals in the direction of sex difference, if present. Experiments are needed to establish the roles of androgens and estrogens in establishing these sex differences in lizards. Anat Rec, 301:1169–1178, 2018. © 2018 Wiley Periodicals, Inc. 相似文献
77.
RC Cook MBChB J Zachariah MB BS F Cree BSc HE Harrison PhD 《International journal of clinical practice》1996,50(3):125-128
SUMMARY A new amoxycillin/clavulanate regimen (‘Augmentin-Duo’ 400/57), to be given orally in two divided doses, has been proposed to overcome the inconvenience of tid dosing. This observer-blind, multicentre study randomised children aged two to 12 years with lower respiratory tract infection to seven days' treatment with either amoxycillin/clavulanate bid at a dose of 25/3.6mg/kg/day (221 patients) or the currently prescribed amoxycillin/clavulanate regimen of 20/5mg/kg/day tid (216 patients). Clinical success (cure) rates at follow up were 81.0% for the bid group and 77.8% for the tid group [difference 3.2%; 95% CI (-4.36, 10.80)], indicating that the regimens were of equivalent efficacy. Both regimens were well tolerated, and there was no statistically significant difference in the incidence of adverse experiences between the two groups. Compliance with study medication was high and similar for both groups (80% compliance: bid 90.0%; tid 87.0%). 相似文献
78.
目的探讨乌司他丁在预防不同胃肠术后吻合口瘘中的效果。方法选取2005年6月~2011年8月于本院进行胃肠术进行治疗的220例患者为研究对象,将其随机分为对照组和观察组各110例,观察组在对照组的基础上加用乌司他丁,后将两组患者中不同术式的吻合口瘘发生率及术前、术后1 d及3 d的血清超敏C反应蛋白(hs-CRP)、白介素2(IL-2)、白介素6(IL-6)、肿瘤坏死因子α(TNF-α)、血液流变学指标进行统计及比较。结果观察组不同术式的吻合口瘘发生率及总发生率均低于对照组,血清hs-CRP、IL-6、TNF-α水平低于对照组,IL-2高于对照组,血液流变学指标改变幅度小于对照组,差异均有统计学意义(均P〈0.05)。结论乌司他丁可以改善胃肠手术患者的炎性状态及血液循环情况,对于降低吻合口瘘的发生率有着积极的作用。 相似文献
79.
H Pickering R Bethune IA Eyre-Brook 《Annals of the Royal College of Surgeons of England》2009,91(3):W1-W2
A 57-year-old-man with a history of malaise, fever,night sweats and shortness of breath presented a diagnostic challenge to his medical team. He was pancytopaenic and had splenomegaly on admission but other investigations, including bone marrow aspiration, proved inconclusive. After the patient deteriorated clinically, the general surgical team was requested to perform a diagnostic splenectomy. The histology of this showed infection with visceral leishmaniasis. He recovered completely with Amphotericin treatment. Although this is a rare condition, particularly for the general surgeon, this case highlights the difficult position surgeons are often put in when performing major surgery diagnostically. 相似文献
80.
目的探讨多聚(ADP-核糖)聚合酶(PARP)抑制剂3-氨基苯甲酰胺(3-AB)在大鼠-肾脏缺血再灌注损伤中的保护作用及对肾组织血管内皮生长因子A(VEGF-A)和中性粒细胞明胶酶相关脂质运载蛋白(NGAL)mRNA表达的影响。方法将54只大鼠随机分为假手术组(S组)、再灌注后模型组(M组)和PARP抑制剂组(P组),每组8只。比较各组大鼠右侧肾动脉缺血再灌注后2、6、12h后的血肌酐和尿素氮水平、肾脏组织病理学变化、肾组织PARP蛋白表达及肾组织VEGF-A和NGAI.mRNA表达。结果(1)M组各时间点的血肌酐、尿素氮水平均高于S组,P组各时间点血肌酐、尿素氮明显低于M组,差异均有统计学意义(P〈0.01);(2)P组肾组织病理学表现较M组改善;(3)P组各时间点肾组织PARP表达明显低于M组,差异有统计学意义(P〈0.05);(4)与M组相比,P组肾组织的VEGF-AmRNA的表达升高,NGALmRNA表达降低,有统计学差异(P〈0.05)。结论PARP抑制剂3AB对大鼠肾脏缺血再灌注损伤具有保护作用,可下调NGAL及上调VEGF-AmRNA表达。 相似文献