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   452篇
  免费   20篇
儿科学   15篇
妇产科学   3篇
基础医学   56篇
口腔科学   12篇
临床医学   45篇
内科学   82篇
皮肤病学   18篇
神经病学   31篇
特种医学   15篇
外科学   80篇
综合类   4篇
预防医学   60篇
眼科学   7篇
药学   23篇
中国医学   6篇
肿瘤学   15篇
  2024年   2篇
  2022年   13篇
  2021年   14篇
  2020年   8篇
  2019年   23篇
  2018年   14篇
  2017年   16篇
  2016年   20篇
  2015年   19篇
  2014年   21篇
  2013年   28篇
  2012年   44篇
  2011年   40篇
  2010年   25篇
  2009年   23篇
  2008年   18篇
  2007年   25篇
  2006年   17篇
  2005年   18篇
  2004年   17篇
  2003年   13篇
  2002年   12篇
  2000年   3篇
  1999年   3篇
  1998年   1篇
  1997年   3篇
  1996年   4篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1990年   1篇
  1984年   2篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1978年   4篇
  1977年   3篇
  1975年   2篇
  1974年   1篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1964年   1篇
排序方式: 共有472条查询结果,搜索用时 0 毫秒
61.
This study investigated the in vitro production of interferon-gamma, interleukin (IL)-10, IL-12, and IL-13, after antigenic stimulation of the cells (with Leishmania antigen and lipopolysaccharide) using whole blood from patients with cutaneous leishmaniasis lesions caused by Leishmania tropica and in normal volunteers with history of cutaneous leishmaniasis.ELISA results showed that the mean production of interferon-gamma by cells of whole blood in patients with lesions in response to Leishmania antigen was significantly lower than corresponding values in volunteers with history of cutaneous leishmaniasis (P< 0.05) and significantly higher levels of IL-10 production in patients with lesions were observed compared with cured volunteers of the disease (P<0.01). A similar level of IL-12, including p40 subunit of IL-12, was detected in both groups tested in this study in response to stimulation of parasite antigen. The levels of the IL-13 after stimulation with Leishmania antigen were significantly more in patients compared with volunteers with history of cutaneous leishmaniasis (P< 0.01). There was no significant difference in the mean production of IFN-gamma, IL-10, IL-12 and IL-13 by PHA or LPS stimulated cells from patients with lesions and volunteers with history of the disease, indicating that there was no qualitative defect in cytokine production in these patients.In this study, we have detected the decreased production of interferon- gamma by cells of patients with lesions of cutaneous leishmaniasis in response to parasite antigen and unbalanced production of regulatory cytokines such as IL-10 and IL-13 using the whole-blood stimulation assay technique. The required small volume of blood and the rapid set up time are the advantages in this assay technique. Using this assay for further immunodetection of cytokines may confirm its value for clinical investigation.  相似文献   
62.

Objective

The purpose of this study was to review the literature to determine whether surface electromyography (EMG) is a reliable tool to assess paraspinal muscle fatigue in healthy subjects and in patients with low back pain (LBP).

Methods

A literature search for the period of 2000 to 2012 was performed, using PubMed, ProQuest, Science Direct, EMBASE, OVID, CINAHL, and MEDLINE databases. Electromyography, reliability, median frequency, paraspinal muscle, endurance, low back pain, and muscle fatigue were used as keywords.

Results

The literature search yielded 178 studies using the above keywords. Twelve articles were selected according to the inclusion criteria of the study. In 7 of the 12 studies, the surface EMG was only applied in healthy subjects, and in 5 studies, the reliability of surface EMG was investigated in patients with LBP or a comparison with a control group. In all of these studies, median frequency was shown to be a reliable EMG parameter to assess paraspinal muscles fatigue. There was a wide variation among studies in terms of methodology, surface EMG parameters, electrode location, procedure, and homogeneity of the study population.

Conclusions

The results suggest that there seems to be a convincing body of evidence to support the merit of surface EMG in the assessment of paraspinal muscle fatigue in healthy subject and in patients with LBP.  相似文献   
63.
Many commonly used retroviral vectors express one gene from the viral long terminal repeat (LTR) promoter and another gene from an internal promoter. We have investigated factors affecting the expression of the luciferase reporter gene from the internal cytomegalovirus-derived promoter of the retroviral vector, LNCX, which contains a LTR-drivenneo gene as a selectable marker. A subline of human HT1080 cells, expressing the murine ecotropic receptor, was infected with retrovirus generated by transient transfection of BOSC 23 packaging cells. Mass populations of cells infected under conditions resulting in different initial infection rates (IIR) and selected with G418, showed highly variable luciferase activity. Luciferase expression in cell populations with IIR≤5% was generally low; many populations with IIR<1% had marginal or no luciferase activity. The loss of luciferase expression in low-IIR populations was associated with G418 selection. In contrast, cell populations with IIR≥6% showed higher luciferase expression, which was strongly correlated with the IIR. Southern hybridization analysis showed that most cells of the low-IIR populations carried one integrated provirus, with a high incidence of structural rearrangements that abolished luciferase activity. In contrast, populations with IIR≥6% contained two or more copies of integrated provirus per cell, and their luciferase activity correlated with the provirus copy number. Luciferase expression was relatively stable in the populations with IIR>1% maintained in the absence of G418. Increasing the selective concentration of G418 or prolonged maintenance of cell populations in the presence of G418 resulted in higher incidence of provirus rearrangements and decreased luciferase expression. These results indicate that the negative effect of selection for the LTR-driven gene on gene expression from an internal promoter depends on the selection stringency and can be obviated by increasing the infection rate.  相似文献   
64.
BACKGROUND: Our objective was to determine if intraoperative injection of technetium-99m-labeled sulfur colloid is as effective as preoperative injection in the detection of sentinel lymph nodes (SLNs). METHODS: Two hundred consecutive patients with breast cancer underwent SLN biopsy examination. Radiocolloid was injected in the preoperative area (group A) or immediately after induction of anesthesia in the operating room (group B). RESULTS: The SLN detection rate was similar for groups A (96%) and B (100%; P = .2). Radioactive SLNs were detected in 95% of patients in group A and in 97% of patients in group B (P = .1). The mean number of SLNs harvested was 1.6 and 2.1 for groups A and B, respectively. There was no significant difference in positive SLNs between groups (P = .11). CONCLUSIONS: Intraoperative injection of sulfur colloid is highly effective in the detection of SLNs, avoiding patient discomfort and surgical schedule delays.  相似文献   
65.
A study of diphtheria in Iran was undertaken during the summer of 1969. Diphtheria was found to be more common among the younger people and to reach its peak 3 months after the start of the school term, during the coldest period of the year. Owing to the liberal use of antibiotics a number of modified clinical cases were observed. Of the strains isolated, 89·7% were gravis, 1·3% intermedius and 9% mitis. Phage typing of these strains showed that the mitis and intermedius strains could only be typed by adapted phages and the majority of gravis strains were phage type XIV, which is the epidemic type seen in other countries.  相似文献   
66.
Antibiotics are of equal importance to antitoxin in the treatment of diphtheria, as an effective antibiotic rapidly halts the production of toxin. There appear to have been only two reports of the sensitivity of diphtheria bacilli to various antibiotics and these are based on the examination of less than 60 strains. In this paper the sensitivity of 192 strains to eight representative antibiotics is reported.  相似文献   
67.
The pattern of dissemination of prostatic carcinoma varies, but skeletal metastasis is the single most common symptomatic mode of presentation. The clinical course and treatment of the 2 cases presenting with symptomatic metastases to the retroperitoneum are described in detail and pertinent literature is reviewed.  相似文献   
68.
69.
Mazdak H  Meshki I  Ghassami F 《European urology》2007,51(4):1089-92; discussion 1092
OBJECTIVES: Urethral stricture is one of the oldest known urologic diseases and remains a common problem with high morbidity. Internal urethrotomy refers to any procedure that opens the stricture by incising or ablating it transurethrally. The most common complication of internal urethrotomy is stricture recurrence. The curative success rate of internal urethrotomy is approximately 20%. Mitomycin C has antifibroblast and anticollagen properties and in sporadic reports of animal and clinical studies it has increased the success rate of trabeculectomy and myringotomy. This study evaluated the efficacy of mitomycin C in the prevention of anterior urethral stricture recurrence after internal urethrotomy. PATIENTS AND METHODS: Forty male patients with anterior urethral strictures were randomized to undergo internal urethrotomy with or without urethral submucosal mitomycin C injection. Using general anaesthesia, the urethrotomy was performed under direct vision. Mitomycin C (0.1mg) was injected submucosally at the urethrotomy site in 20 patients. The patients were re-evaluated after 6 mo and the stricture recurrence rate was compared between the two groups (chi(2) analysis). RESULTS: Urethral stricture recurred in 2 patients (10%) in the mitomycin C-treated group and in 10 patients (50%) in the other group. This difference in stricture recurrence between the two groups was statistically significant (p=0.006). CONCLUSIONS: To our knowledge, this is the first prospective, randomized, clinical trial to evaluate the efficacy of mitomycin C application in internal urethrotomy. Submucosal injection of mitomycin C significantly reduced stricture recurrence after internal urethrotomy. Further investigations are warranted to confirm its efficacy and safety.  相似文献   
70.
PROBLEM: Primary Immunodeficiency Disorders (PiD) are a heterogeneous group of genetic disorders, with different modes of inheritance. This study was accomplished in order to determine the frequency of consanguineous marriages in the families of patients with PiD. METHOD: In this study, the records 515 Iranian PiD patients were reviewed during a 25-year period. RESULTS: The mean proportion of consanguineous marriages was 65.6% among PiD patients, while the overall rate was 38.6% in the country. The rate of consanguinity was 77.8% in cellular immunodeficiencies, 75.8% in combined immunodeficiencies, 72.5% in defects of phagocytic function, 58.6% in other immunodefiiencies, 54.1% in predominantly antibody deficiencies, and 50% in complement deficiencies. Moreover all patients with immunodeficiency associated with other diseases had consanguineous parents. Such marriages were most common in the parents of patients with Chediak-Higashi syndrome, severe combined immunodeficiencies, primary CD4 deficiency, ataxia-telangiectasia, selective IgG class deficiencies, chronic granulomatous disease, and Schwachman syndrome. CONCLUSIONS: It is important to inform the general population about the dangers of consanguinity, which is very common in some areas such as Iran. Premarital examination to avoid genetic diseases could be suggested, especially in a community where the rate of consanguineous marriage is high.  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