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   692篇
  免费   36篇
  国内免费   23篇
耳鼻咽喉   4篇
儿科学   21篇
妇产科学   8篇
基础医学   76篇
口腔科学   119篇
临床医学   58篇
内科学   126篇
皮肤病学   31篇
神经病学   38篇
特种医学   73篇
外科学   47篇
综合类   20篇
预防医学   55篇
药学   37篇
肿瘤学   38篇
  2023年   3篇
  2021年   4篇
  2020年   2篇
  2019年   7篇
  2018年   13篇
  2017年   12篇
  2016年   6篇
  2015年   16篇
  2014年   11篇
  2013年   29篇
  2012年   33篇
  2011年   25篇
  2010年   28篇
  2009年   34篇
  2008年   25篇
  2007年   39篇
  2006年   25篇
  2005年   44篇
  2004年   17篇
  2003年   21篇
  2002年   22篇
  2001年   12篇
  2000年   11篇
  1999年   21篇
  1998年   23篇
  1997年   17篇
  1996年   31篇
  1995年   11篇
  1994年   21篇
  1993年   9篇
  1992年   11篇
  1991年   12篇
  1990年   17篇
  1989年   15篇
  1988年   16篇
  1987年   14篇
  1986年   13篇
  1985年   13篇
  1984年   5篇
  1983年   8篇
  1982年   9篇
  1981年   7篇
  1980年   7篇
  1979年   5篇
  1978年   3篇
  1977年   6篇
  1976年   6篇
  1975年   3篇
  1973年   2篇
  1946年   1篇
排序方式: 共有751条查询结果,搜索用时 15 毫秒
1.
Pityriasis rosea (PR) is a relatively common disease although its aetiology has not yet been identified. It occurs worldwide and there is no racial susceptibility factor. It usually affects teenagers and young adults between 10 and 35 years of age. Typical PR is much easier to diagnose than the rare atypical forms. We report a rare case of vesicular PR in a black woman who had vesicular lesions limited to her palms and soles in addition to regular typical lesions. We devised an efficient oral erythromycin treatment for this patient.  相似文献   
2.
3.
4.
5.
6.
进一步研究了抗三尖杉酯碱的HL-60细胞(HR20)抗细胞凋亡的机制及该抗性和抗药性的关系。结果表明,环孢菌素A(CsA)20,10μg·ml ̄(-1)诱导HL-60细胞发生凋亡,而阻断HR20细胞于G_1期,就不能诱导细胞发生凋亡。低浓度的CsA明显增加柔红霉素在HR20细胞内的积聚,其逆转抗药性作用与阻断细胞周期运行无关。CsA10μg·ml ̄(-1)处理HR20细胞,可引起50kDa的蛋白质高度磷酸化。结果提示:环孢菌素A阻断抗三尖杉酯碱的HL-60细胞于G_1期,而诱导敏感的HL-60细胞发生凋亡,其阻断作用与抗药性无关  相似文献   
7.
This study aims to provide a quantitative analysis of the factors affecting the actual precision and stability of optoelectronic and electromagnetic tracking systems in computer-aided surgery under real clinical/intraoperative conditions. A "phantom-skull" with five precisely determined reference distances between marker spheres is used for all measurements. Three optoelectronic and one electromagnetic tracking systems are included in this study. The experimental design is divided into three parts: (1) evaluation of serial- and multislice-CT (computed tomography) images of the phantom-skull for the precision of distance measurements by means of navigation software without a digitizer, (2) digitizer measurements under realistic intraoperative conditions with the factors OR-lamp (radiating into the field of view of the digitizer) or/and "handling with ferromagnetic surgical instruments" (in the field of view of the digitizer) and (3) "point-measurements" to analyze the influence of changes in the angle of inclination of the stylus axis. Deviations between reference distances and measured values are statistically investigated by means of analysis of variance. Computerized measurements of distances based on serial-CT data were more precise than based on multislice-CT data. All tracking systems included in this study proved to be considerably less precise under realistic OR conditions when compared to the technical specifications in the manuals of the systems. Changes in the angle of inclination of the stylus axis resulted in deviations of up to 3.40 mm (mean deviations for all systems ranging from 0.49 to 1.42 mm, variances ranging from 0.09 to 1.44 mm), indicating a strong need for improvements of stylus design. The electromagnetic tracking system investigated in this study was not significantly affected by small ferromagnetic surgical instruments.  相似文献   
8.
Needle biopsy of renal allografts: comparison of two techniques   总被引:2,自引:0,他引:2  
Two techniques for renal allograft biopsy were retrospectively evaluated to compare relative safety and efficacy. After ultrasound (US) localization of the kidney and biopsy with a hand-held 14-gauge cutting needle, an adequate specimen was obtained in 74 of 77 cases (96%). Major complications occurred in six of these 77 cases (8%). One hundred four biopsies were performed by using a smaller 18-gauge cutting needle with a spring-loaded biopsy "gun" and real-time US guidance. With this newer technique, specimens adequate for diagnosis were obtained in 99 biopsies (95%). There was a single major complication with this technique (1%). The 18-gauge needle with real-time US guidance yields comparably adequate specimens with a lower frequency of complications.  相似文献   
9.
A questionnaire was administered to the nursing staff of a large teaching hospital to determine: 1) sources of stress in caring for AIDS patients; 2) perceived sources of stress in being an AIDS patient; and 3) attitudes towards "deserving" various illnesses. Principal components analyses revealed a number of factors related to increased stress, including: general concerns about the care of these patients; specific concerns in crises situations; and concerns regarding the personal/social implications of caring for these individuals. These factors were not related to either prior experience taking care of AIDS patients, or nursing specialty. In addition, persons with AIDS were viewed as "deserving" their illness in much the same way as noncompliant diabetic or renal patients. Potential implications of these findings and suggestions for future research directed towards mitigating these occupational stressors are given.  相似文献   
10.
The concentrations of 1-hydroxypyrene (1-HOPYR), and 1-, 2-, 3-, and 4-hydroxyphenanthrene (HOPHE) as metabolites of pyrene and phenanthrene, were measured in urine samples collected from 124 housewives (27 smokers and 97 nonsmokers) living in Bottrop, an industrial city located in the Ruhr area in Germany. The urine samples were analyzed by a very sensitive and practical high-performance liquid chromatographic (HPLC) method using a two-column switching technique and a special precolumn packing material followed by fluorescence detection. The polycyclic aromatic hydrocarbon (PAH) metabolites are selectively enriched on the precolumn and separated from the matrix. Therefore, laborious clean-up steps were omitted. The above-mentioned PAH metabolites could be detected in all urine samples investigated. Smokers had significantly higher urine concentrations of 1-HOPYR (median 0.48 g/g creatinine), 3-HOPHE (median 0.61 g/g creatinine), 2-HOPHE (0.41 g/g creatinine) and 4-HOPHE (median 0.10 g/g creatinine) than non-smokers (median 0.15 g/g creatinine, 0.31 g/g creatinine, 0.31 g/g creatinine and 0.04g/g creatinine, respectively). The study shows that the influence of smoking is of such an order of magnitude that potential environmental exposure to PAH in this highly industrialized area is obscured by smoking habits. Furthermore, it can be concluded that the determination of 1-HOPYR, 1-, 2-, 3-, and 4-HOPHE in urine is a diagnostically useful method for the biological monitoring of persons environmentally exposed to PAH.  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