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   192篇
  免费   13篇
  国内免费   66篇
基础医学   19篇
口腔科学   2篇
临床医学   52篇
内科学   39篇
皮肤病学   1篇
特种医学   12篇
外科学   66篇
综合类   21篇
预防医学   2篇
眼科学   1篇
药学   31篇
肿瘤学   25篇
  2022年   1篇
  2021年   5篇
  2019年   1篇
  2018年   6篇
  2016年   2篇
  2015年   3篇
  2014年   4篇
  2013年   6篇
  2012年   8篇
  2011年   2篇
  2010年   5篇
  2009年   6篇
  2008年   5篇
  2007年   42篇
  2006年   10篇
  2005年   10篇
  2004年   10篇
  2003年   3篇
  2002年   10篇
  2001年   9篇
  2000年   14篇
  1999年   13篇
  1998年   8篇
  1997年   4篇
  1996年   2篇
  1995年   5篇
  1994年   5篇
  1993年   5篇
  1992年   12篇
  1991年   5篇
  1990年   8篇
  1989年   6篇
  1988年   5篇
  1987年   9篇
  1986年   7篇
  1984年   4篇
  1983年   3篇
  1979年   3篇
  1978年   1篇
  1976年   1篇
  1974年   1篇
  1969年   1篇
  1968年   1篇
排序方式: 共有271条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
本文依据一组含有不同比例待测和干扰组分的标准混合液的吸收值,采用一元线性回归方法,在选择最佳测定波长对的同时建立标准工作曲线方程,使其更符合实际作品测定时的情况,提高了结果的精度和可靠性,并使计算量和实验工作量得以降低。应用于复方氨基比林注射液中三组分氨基比林、安替比林和巴比妥的同时测定,其平均回收率分别为99.8%,100.4%和99.8%,变异系数分别为0.59,1.48和1.05,结果优于卡尔曼滤波法、偏最小二乘法和目标因子分析法。  相似文献   
45.
改性羟基磷灰石骨修复纳米复合材料的制备及生物学评价   总被引:5,自引:7,他引:5  
目的:制备羟基磷灰石/聚乳酸聚乙醇酸骨修复材料,并对其进行生物学评价。方法:实验于2006-06/2007-02在中科院长春应用化学研究所完成材料制备,在吉林大学基础医学院实验动物中心完成动物实验。将低聚乳酸的羧基与羟基磷灰石表面的钙原子用化学键连接,得到表面接枝聚左旋乳酸的羟基磷灰石,将其与聚乳酸聚乙醇酸共混,得到复合材料PLLA-g-HA/PLGA。溶于氯仿后铺膜(厚0.2mm),用DMEM培养液浸泡材料膜制备浸提液。首先,进行材料生物安全性实验:①细胞毒性实验:将浸提液与培养液混合,接种兔成骨细胞,培养24h,MTT法检测细胞增殖,计算细胞增殖率和细胞毒性级(细胞毒性级0或1级为合格)。②全身毒性实验:小鼠以50mL/kg的剂量静脉注射浸提液,观察72h内小鼠中毒症状。③皮肤刺激实验:兔脊柱两侧皮内注射材料浸提液,观察72h内皮肤有无异常反应。④热原实验:自兔耳缘静脉注入浸提液(10mL/kg)。注射后每0.5h测肛温1次,共6次,以6次中最高的1次减去正常体温,计为升高度数。其次,对复合材料进行细胞黏附性检测:将复合材料制成1%氯仿溶液,涂于硅化的盖玻片上,置于6孔板,每孔接种1×105个成骨细胞,培养3d,在2,24,72h行FITC荧光染色,数码摄像系统拍摄细胞荧光照片。结果:制备了新型PLLA-g-HA/PLGA复合材料。①生物安全性实验结果:MTT实验检测复合材料细胞增殖率为94.8%,细胞毒性级为1级;全身毒性实验中动物无死亡、惊厥、瘫痪、呼吸抑制、腹泻和体质量下降等不良反应;热原实验中兔体温最大的变化值是0.25℃(国家标准为<0.6℃);皮肤刺激实验中未见任何刺激反应,无红斑、焦痂、水肿表现。②细胞黏附性实验结果:细胞接种后2h可见少量细胞开始贴壁;24h时可见贴壁细胞明显增多,并呈聚集生长;培养3d后可见细胞逐渐融合,细胞状态良好。结论:新型PLLA-g-HA/PLGA复合材料符合生物材料细胞毒性要求,按毒性剂量分级属无毒级,无致热原性、对皮肤无刺激作用,具有良好的生物相容性和细胞黏附性。  相似文献   
46.
The aim of the study was to evaluate the QT dispersion and the severity of arrhythmias in hypertensive patients according to the asymmetry of the left ventricular hypertrophy. The study group consisted of 47 hypertensive patients. In 24 of them the left ventricular hypertrophy was symmetrical (group I) and in 23--asymmetrical (group II). For the evaluation of the left ventricular hypertrophy its thickness was analyzed in 13 segments. The ratio between the maximum and minimum thickness from any location was determined as the asymmetry index (AI). The value of this index 1,3 distinguished between patients with the symmetrical and asymmetrical left ventricular hypertrophy. 20 healthy subjects were examined as a control group (group III). All subjects underwent physical examination, the standard 12-lead electrocardiogram (ECG), twenty-four hour Holter recording and echocardiography. All the results for the QT dispersion (QTd, QTdc, QTdR) were highest in group II, lower in patients from group I and the lowest were observed in the control group. The differences in all parameters between group I and II were statistically significant: for QTd--V p < 0.01, QTdc--p < 0.05, QTdR--p < 0.05. The differences between groups II and III as well as I and III were statistically significant for all QT dispersion parameters: for QTd--p < 0.001 and p < 0.01 respectively, QTdc--p < 0.001, QTdR--p < 0.001 for both groups. We have observed a very distinct positive correlation between the asymmetry index and QTd, QTdc, QTdR (p < 0.001). These values correlated also, but less distinctly with the left ventricular mass index--LVMI (p < 0.05). The frequency and severity of ventricular ectopic beats did not differ significantly between group I and II. The results obtained indicate the lack of connection between the frequency of ventricular premature complexes and (1) all QT dispersion parameters, (2) LVMI, (3) AI. Supraventricular premature complexes occurred significantly more frequently in patients with the asymmetrical left ventricular hypertrophy compared to the group with the regular left ventricular hypertrophy (p < 0.05) and control group (p < 0.01). CONCLUSIONS: The left ventricular hypertrophy in primary hypertension may increase the QT dispersion. It seems that asymmetry of the left ventricular hypertrophy reinforces this increase. The increased QT dispersion in primary hypertension does not influence significantly the occurrence of ventricular arrhythmias.  相似文献   
47.
Because interleukin-10 (IL-10) is a potent differentiation factor of human B cells into mature plasma cells, we investigated its effect on human malignant plasma cells. IL-10 did not induce any differentiation and increase in Ig synthesis in four human IL-6-dependent malignant plasma cell lines. However, it stimulated the proliferation of two of four cytokine-dependent cell lines in the absence of IL-6 and IL-10- dependent myeloma cell lines have been obtained. The myeloma cell growth activity of IL-10 was unaffected by anti-IL-6 and anti-IL-6R antibodies. Similarly, IL-10 stimulated (P = .001) the proliferation of freshly-explanted myeloma cells in IL-6-deprived cultures of tumor samples from patients with active multiple myeloma (MM) and produced twice as many myeloma cells in these cultures. Again, this cytokine was unable to induce further differentiation (assessed by rate of Ig production) of fresh myeloma cells. A very sensitive enzyme-linked immunosorbent assay (ELISA; 1 pg/mL) only rarely detected IL-10 in the sera of MM patients (3 of 89). On the contrary, serum IL-10 was detected in 60% of patients with plasma cell leukemia (12 of 20). These data show that IL-10 is an IL-6-unrelated growth factor for malignant plasmablastic cells. This cytokine could be involved in the late phase of MM in vivo.  相似文献   
48.

INTRODUCTION

The preliminary results of a pyrocarbon interpositional radiocarpal implant in a small cohort of patients were reviewed. As it is currently only a limited release product, we describe to potential users early complications and negative outcomes.

METHODS

Patients were assessed using pain levels, ranges of motion, grip strength, type of and time to return to work as well as pre-operative and post-operative DASH (Disabilities of the Arm, Shoulder and Hand) scores. Radiographs were taken and patient satisfaction was recorded.

RESULTS

All six patients were contacted. One was not satisfied. Three had reduced motion. None experienced squeaking. There were no immediate or late post-operative complications. There was one early volar displacement of an implant.

CONCLUSIONS

Although our early results are somewhat encouraging, further and longer studies are warranted before supporting the use of this particular pyrocarbon implant as a primary procedure.  相似文献   
49.
50.
目的 :研究硝苯吡啶以及硝苯吡啶与格列本脲合用对空腹大鼠和肾上腺素诱发高血糖大鼠血糖水平的影响。方法 :本实验采用葡萄糖氧化酶法测定血糖含量。结果 :硝苯吡啶 2 .5mg/kgig使空腹大鼠血糖水平显著升高(P <0 .0 1 ) ,并加重肾上腺素诱发的高血糖反应。而硝苯吡啶与降糖药格列本脲 0 .9mg/kg合用时不影响空腹大鼠的血糖水平 ,硝苯吡啶对肾上腺素诱发高血糖大鼠灌胃格列本脲后的降血糖作用亦无明显影响。结论 :尽管硝苯吡啶对空腹大鼠以及肾上腺素诱发高血糖大鼠有显著升高血糖的作用 ,但对格列本脲的降血糖作用无明显不良影响  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