全文获取类型
收费全文 | 1619768篇 |
免费 | 132815篇 |
国内免费 | 2610篇 |
专业分类
耳鼻咽喉 | 21780篇 |
儿科学 | 53546篇 |
妇产科学 | 46884篇 |
基础医学 | 230336篇 |
口腔科学 | 47432篇 |
临床医学 | 144093篇 |
内科学 | 317979篇 |
皮肤病学 | 34274篇 |
神经病学 | 131909篇 |
特种医学 | 64996篇 |
外国民族医学 | 474篇 |
外科学 | 245117篇 |
综合类 | 39948篇 |
现状与发展 | 3篇 |
一般理论 | 572篇 |
预防医学 | 125449篇 |
眼科学 | 36633篇 |
药学 | 122342篇 |
3篇 | |
中国医学 | 2987篇 |
肿瘤学 | 88436篇 |
出版年
2018年 | 15112篇 |
2016年 | 13224篇 |
2015年 | 15390篇 |
2014年 | 21175篇 |
2013年 | 32242篇 |
2012年 | 43776篇 |
2011年 | 46001篇 |
2010年 | 27044篇 |
2009年 | 25993篇 |
2008年 | 44208篇 |
2007年 | 46453篇 |
2006年 | 47251篇 |
2005年 | 45913篇 |
2004年 | 45262篇 |
2003年 | 43346篇 |
2002年 | 42388篇 |
2001年 | 75830篇 |
2000年 | 78463篇 |
1999年 | 66551篇 |
1998年 | 17958篇 |
1997年 | 16526篇 |
1996年 | 16472篇 |
1995年 | 16182篇 |
1994年 | 15221篇 |
1993年 | 14365篇 |
1992年 | 55559篇 |
1991年 | 53897篇 |
1990年 | 52669篇 |
1989年 | 50948篇 |
1988年 | 47322篇 |
1987年 | 46657篇 |
1986年 | 44359篇 |
1985年 | 42923篇 |
1984年 | 32158篇 |
1983年 | 27659篇 |
1982年 | 16278篇 |
1981年 | 14549篇 |
1980年 | 13669篇 |
1979年 | 30527篇 |
1978年 | 21138篇 |
1977年 | 17815篇 |
1976年 | 16751篇 |
1975年 | 17618篇 |
1974年 | 21524篇 |
1973年 | 20708篇 |
1972年 | 18893篇 |
1971年 | 17809篇 |
1970年 | 16321篇 |
1969年 | 15291篇 |
1968年 | 13971篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Mahmoud R Hussein Dalia A Elsers Sabah A Fadel Abd-Elhady M Omar 《European journal of cancer prevention》2006,15(1):64-68
Although melanocytic skin lesions have been recognized since antiquity, their literature was limited to Caucasians. To date, the clinicopathologic features of these lesions in Egyptians are still unknown. To define these features, diagnostic records of the melanocytic skin lesions received at the Pathology Department, Assuit University Hospitals (1989-2004) were reviewed. The lesions examined included 12 benign naevi (BN), 10 dysplastic naevi (DN), and 21 cutaneous malignant melanomas (CMMs). The DN and CMMs were more common in men than in women (2 : 1 and 1.5 : 1, respectively) while BN were more common in women (2 : 1). The average age incidence was 33+/-5, 38+/-7 and 54+/-3 years, for BN, DN and CMM, respectively. The lower limb (13/21, 62%), head and neck (7/21, 33%) were the most common sites for CMMs. The average size (mm) was 2+/-0.3, 4+/-0.6 and 21+/-0.3 for BN, DN and CMMs, respectively. Recurrence occurred in 10% of CMMs. Histologically, CMMs were of nodular type and composed of epithelioid (7/21, 33%), spindle cells (1/21, 5%), or mixed cells (13/21, 62%). The mean tumour thickness (Breslow) was 6+/-0.5 mm. CMMs included two of 21(9%), three of 21(14%), six of 21(38%), and 10 of 21(38%) with Clark level II, III, IV and V. In Egypt, CMM is the third most common cutaneous neoplasm following squamous and basal cell carcinomas. Compared with Western societies, melanoma has a male sex predilection, similar histological features but different topographical distribution and rare incidence. The striking difference from Western series is the incidence of nodular melanoma - in the West this represents 15-30% of melanomas, with superficial spreading being the majority. Another key difference from the West is the 'sun-bed' culture of the West and the desire to have suntans. This is the first study that reports the clinicopathologic features of melanocytic skin lesions in Egypt. 相似文献
62.
Hale Sayan V Haktan Ozacmak Aysel Guven R Gulhan Aktas I Diler Ozacmak 《Journal of investigative surgery》2006,19(3):163-173
Erythropoietin exerts hematopoietic effects by stimulating proliferation of early erythroid precursors. Nonhematopoietic effects of erythropoietin have also been shown. It may act as a new angiogenic factor in wound healing. This study aimed to investigate the effect of systemic administration of recombinant human erythropoietin on wound healing in mice. Dorsal incisional wounds were performed in mice, which were then divided into two groups; a group treated for 7 days with recombinant human erythropoietin, and a control group. Sacrificing animals on day 7, the wound tissues were collected for analysis of wound breaking strength, malondialdehyde, a marker of lipid peroxidation, hydroxyproline, an index of reparative collagen deposition, reduced glutathione levels, and for histological evaluation. The immunohistochemical determination of vascular endothelial growth factor (VEGF) which is believed to be the most prevalent angiogenic factor throughout the skin repair process, was also studied. The treatment significantly increased wound breaking strength by decreasing malondialdehyde and increasing hydroxyproline levels on day 7 after wounding. No statistically meaningful change was observed in reduced glutathione content. VEGF was immunostained significantly more on wound tissue of treated animals compared to the control group. Recombinant human erythropoietin treatment may be effective in wound healing due to inhibition of lipid peroxidation, deposition of collagen, and VEGF expression in wound area. 相似文献
63.
64.
Pankaj Dabir Snehal Dabir B V Siva Prasad M V R Reddy 《Infection, genetics and evolution》2006,6(4):287-291
Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response. 相似文献
65.
Steven M Shechter Andrew J Schaefer R Scott Braithwaite Mark S Roberts 《Medical decision making》2006,26(5):550-553
The authors discuss techniques for Monte Carlo (MC) cohort simulations that reduce the number of simulation replications required to achieve a given degree of precision for various output measures. Known as variance reduction techniques, they are often used in industrial engineering and operations research models, but they are seldom used in medical models. However, most MC cohort simulations are well suited to the implementation of these techniques. The authors discuss the cost of implementation versus the benefit of reduced replications. 相似文献
66.
Michiel R. de Boer Jos Twisk Annette C. Moll Hennie J. M. Völker-Dieben Henrica C. W. de Vet Ger H. M. B. van Rens 《Ophthalmic & physiological optics》2006,26(6):535-544
Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo. 相似文献
67.
Claire M Rickard Brigit L Roberts Jonathon Foote Matthew R McGrail 《Dimensions of critical care nursing》2006,25(5):234-242
Research coordinators in intensive care are a growing specialty about which little is known. This cross-sectional study surveyed the Australia and New Zealand Intensive Care Research Coordinators' Group (n = 49) regarding demographics, education, employment history, job structure, and role content. Most research coordinators were highly qualified and experienced nurses who undertake pharmaceutical trials, multicenter projects, departmental medical and nursing research, audits and data registries, and their own projects. 相似文献
68.
69.
70.
Both vascular surgery and endovascular interventions traumatise the arterial wall, especially the endothelium. The vessel responds with neointimal hyperplasia and/or constrictive remodelling, and this is still the limiting factor in curative interventions. Stent placement prevents constrictive remodelling but is the main trigger for in-stent restenosis. Hyperproliferation of neointimal tissue is the main response to arterial thrombosis, local inflammation or medio-intimal injury such as occurs, for example, after balloon dilatation in the region of arterial anastomoses or of a thrombectomy (Fogarty-manoeuvre). At present, research on prevention of restenosis is focused on inhibiting neointimal hyperproliferation by using drug-eluting stents, and especially sirolimus- or paclitaxel-eluting stents. In addition, further experimental research work is in progress, with the aim of esablishing new treatment regimens and solving the problem of neointimal formation, thrombosis and constrictive remodelling. These include both local and systemic pharmacological therapy, brachy- and laser therapy, and many genetic treatment options, some of which are currently the subjects of experimental studies and early-stage clinical trials. Gene therapy seems like a promising way of preventing restenosis, but has not yet been tested in clinical trials. In the near future, selective, simultaneous, and perhaps even polyphasic regulation for gene silencing of two or more genes involved in the development of restenosis could improve the long-term patency rate. 相似文献