全文获取类型
收费全文 | 1389篇 |
免费 | 81篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 43篇 |
妇产科学 | 29篇 |
基础医学 | 161篇 |
口腔科学 | 41篇 |
临床医学 | 131篇 |
内科学 | 313篇 |
皮肤病学 | 17篇 |
神经病学 | 97篇 |
特种医学 | 201篇 |
外科学 | 110篇 |
综合类 | 48篇 |
一般理论 | 2篇 |
预防医学 | 110篇 |
眼科学 | 10篇 |
药学 | 67篇 |
中国医学 | 1篇 |
肿瘤学 | 92篇 |
出版年
2023年 | 6篇 |
2021年 | 27篇 |
2020年 | 15篇 |
2019年 | 19篇 |
2018年 | 30篇 |
2017年 | 19篇 |
2016年 | 19篇 |
2015年 | 33篇 |
2014年 | 35篇 |
2013年 | 39篇 |
2012年 | 64篇 |
2011年 | 74篇 |
2010年 | 51篇 |
2009年 | 45篇 |
2008年 | 76篇 |
2007年 | 58篇 |
2006年 | 66篇 |
2005年 | 59篇 |
2004年 | 42篇 |
2003年 | 51篇 |
2002年 | 53篇 |
2001年 | 35篇 |
2000年 | 40篇 |
1999年 | 47篇 |
1998年 | 25篇 |
1997年 | 50篇 |
1996年 | 35篇 |
1995年 | 26篇 |
1994年 | 21篇 |
1993年 | 18篇 |
1992年 | 24篇 |
1991年 | 22篇 |
1990年 | 18篇 |
1989年 | 15篇 |
1988年 | 18篇 |
1987年 | 26篇 |
1986年 | 23篇 |
1985年 | 17篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 16篇 |
1980年 | 14篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1972年 | 4篇 |
1966年 | 6篇 |
排序方式: 共有1474条查询结果,搜索用时 46 毫秒
1.
Objective: Attrition from Canadian medical degree programs was never described despite differences in admissions requirements at the 17 faculties of medicine. Knowledge on attrition metrics could help the faculties evaluate new avenues for addressing the Association of Faculties of Medicine’s (AFMC) Future of Medical Education in Canada (FMEC MD) recommendation to enhance admissions practices with the goal to improve social accountability and student diversity.Method: AFMC databases were used to track medical degree completion of all Canadian M.D. students who enrolled between 2003 and 2007. Students were followed and assigned an M.D. completion status as of by July 1, 2013. Bivariate statistics were used to evaluate if demographic, admission and degree progression variables were associated with medical school attrition.Results: Of 11,454 students enrolled in Canadian M.D. programs from 2003 to 2007, only 197 (1.7%) did not complete. Québec had significantly higher attrition than other jurisdictions with age, educational attainment at time of enrolment, MCAT completion and struggling academically associated with attrition.Conclusion: Attrition from Canadian MD programs is rare and associated with differences in admission requirements and possibly suggests an optimum life stage for medical studies. Improved knowledge of attrition-related factors may offer an additional level of evidence for improving the alignment between admissions policies and the social accountability objectives of medical schools. 相似文献
2.
3.
4.
5.
6.
Perineural hemangiomas in the upper extremity have been the subject of few reports. We found only eight such cases reported in the literature. We report four additional cases in which there were neurologic symptoms. The specific diagnosis of cavernous hemangioma was not made preoperatively in any of the patients. The greater the extent of intrafascicular involvement, the more difficult is total eradication of the hemangioma. 相似文献
7.
Losier M Fortin JF Cantin R Bergeron MG Tremblay MJ 《Clinical immunology (Orlando, Fla.)》2003,108(2):111-118
The role of the supplementary interaction between virion-bound host ICAM-1 and LFA-1 on target cells in sensitivity to neutralization of human immunodeficiency virus type 1 (HIV-1) is poorly studied. Serum samples from four long-term nonprogressors (LTNPs) and sequential sera from one progressor were used to assess neutralization sensitivity of isogenic ICAM-1-negative and ICAM-1-bearing HIV-1(NL4-3), a prototype of T-cell-line-adapted viruses. We found that virus neutralization sensitivity to the studied sera is not modified by the additional interaction between virally embedded ICAM-1 and LFA-1 under an inactive state. However, expression on the target cell surface of an activated LFA-1 form renders ICAM-1-bearing virus particles, but not viruses devoid of ICAM-1, more refractory to neutralization by sera from three out of four LTNPs and all sequential sera from the person who has experienced a progression of the HIV-1-associated disease. Although no conclusive correlation could be drawn between virus susceptibility to neutralization and the disease status or stages of HIV-1 infection, these findings demonstrate that other nonspecific virus-cell interactions mediated by virion-anchored host proteins and their normal cognate ligands on target cells represent factors that can affect the mechanism of HIV-1 neutralization. 相似文献
8.
Real-time PCR assay for detection of fluoroquinolone resistance associated with grlA mutations in Staphylococcus aureus 下载免费PDF全文
Lapierre P Huletsky A Fortin V Picard FJ Roy PH Ouellette M Bergeron MG 《Journal of clinical microbiology》2003,41(7):3246-3251
Resistance to fluoroquinolones among clinical isolates of Staphylococcus aureus has become a clinical problem. Therefore, a rapid method to identify S. aureus and its susceptibility to fluoroquinolones could provide clinicians with a useful tool for the appropriate use of these antimicrobial agents in the health care settings. In this study, we developed a rapid real-time PCR assay for the detection of S. aureus and mutations at codons Ser-80 and Glu-84 of the grlA gene encoding the DNA topoisomerase IV, which are associated with decreased susceptibility to fluoroquinolones. The detection limit of the assay was 10 genome copies per reaction. The PCR assay was negative with DNA from all 26 non-S. aureus bacterial species tested. A total of 85 S. aureus isolates with various levels of fluoroquinolone resistance was tested with the PCR assay. The PCR assay correctly identified 100% of the S. aureus isolates tested compared to conventional culture methods. The correlation between the MICs of ciprofloxacin, levofloxacin, and gatifloxacin and the PCR results was 98.8%. The total time required for the identification of S. aureus and determination of its susceptibility to fluoroquinolones was about 45 min, including DNA extraction. This new rapid PCR assay represents a powerful method for the detection of S. aureus and its susceptibility to fluoroquinolones. 相似文献
9.
Marylne Fortin Marie-Jose Ouellette Raymond D. Lambert 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,38(2):129-139
PROBLEM: During normal pregnancy, major changes occur in the production of Th2/Th1 cytokines at the feto-maternal interface. Th2 cytokines such as interleukin-4 (IL-4) or interleukin-10 (IL-10) are predominantly produced locally in the uterine and placental tissues, whereas the production of Th1 cytokines such as tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) are decreased. Because these modulations might be induced by the embryo, the current study was carried out to test the effect of rabbit blastocoelic fluid on the production of Th2/Th1 cytokines by lymphocytes, and to investiate the possible implication of transforming growth factor β2 (TGF-β2) prostaglandin E2 (PGE2) as modulators of the production of these cytokines. METHOD OF STUDY: Human peripheral blood lymphocytes (PBL) were cultured along with ConcanavalinA (Con A), and rabbit blastocoelic fluid was collected on day 12 of gestation (BF d-12). Concentrations of cytokines in culture media were determined by enzyme-linked immunoadsorbent assay (ELISA). RESULTS: Addition of BF d-12 in the culture medium induced a strong inhibition of IL-2, TNF-α, IL-10, and granulocyte-macrophage colony-stimulating factor (GM-CSF) production. However, an initial pretreatment of the lymphocytes with BF d-12, followed by a Con A stimulation, led to a marked increase in GM-CSF production, whereas IL-2, TNF-α, and IL-10 secretions were inhibited. It was also demonstrated, for the first time, that a pretreatment of the lymphocytes with TGF-β2 and PGE2 increased GM-CSF production to the same level reached after the addition of BF d-12. Furthermore, removal of TGF-β2 and PGE2 from BF d-12 by affinity chromatography reduced the effect of BF d-12 on GM-CSF production. CONCLUSIONS: Taken together, these findings suggest that the embryo, in modulating harmful and beneficial cytokine production locally, plays an active role in its protection against maternal immune cellular assault. These results also emphasize the importance of growth factors for successfully maintaining pregnancy. 相似文献
10.
Cholecystokinin-decreased food intake in rhesus monkeys 总被引:1,自引:0,他引:1