全文获取类型
收费全文 | 15298篇 |
免费 | 1212篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 208篇 |
儿科学 | 327篇 |
妇产科学 | 215篇 |
基础医学 | 1898篇 |
口腔科学 | 430篇 |
临床医学 | 1535篇 |
内科学 | 3594篇 |
皮肤病学 | 187篇 |
神经病学 | 1175篇 |
特种医学 | 635篇 |
外科学 | 2300篇 |
综合类 | 316篇 |
一般理论 | 16篇 |
预防医学 | 1153篇 |
眼科学 | 513篇 |
药学 | 1044篇 |
中国医学 | 38篇 |
肿瘤学 | 980篇 |
出版年
2022年 | 69篇 |
2021年 | 191篇 |
2020年 | 96篇 |
2019年 | 191篇 |
2018年 | 214篇 |
2017年 | 167篇 |
2016年 | 204篇 |
2015年 | 250篇 |
2014年 | 397篇 |
2013年 | 664篇 |
2012年 | 823篇 |
2011年 | 895篇 |
2010年 | 491篇 |
2009年 | 472篇 |
2008年 | 884篇 |
2007年 | 996篇 |
2006年 | 1025篇 |
2005年 | 988篇 |
2004年 | 1048篇 |
2003年 | 961篇 |
2002年 | 972篇 |
2001年 | 143篇 |
2000年 | 98篇 |
1999年 | 171篇 |
1998年 | 229篇 |
1997年 | 205篇 |
1996年 | 181篇 |
1995年 | 192篇 |
1994年 | 144篇 |
1993年 | 150篇 |
1992年 | 87篇 |
1991年 | 91篇 |
1990年 | 95篇 |
1989年 | 94篇 |
1988年 | 99篇 |
1987年 | 78篇 |
1986年 | 86篇 |
1985年 | 110篇 |
1984年 | 167篇 |
1983年 | 147篇 |
1982年 | 217篇 |
1981年 | 217篇 |
1980年 | 164篇 |
1979年 | 90篇 |
1978年 | 113篇 |
1977年 | 143篇 |
1976年 | 136篇 |
1975年 | 121篇 |
1974年 | 94篇 |
1973年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Pradip K. Rustagi Tin Han Lynn Ziolkowski Deborah L. Farolino Mark S. Currie Gerald L. Logue 《British journal of haematology》1987,66(4):461-465
The anti-granulocyte activity of serum from patients with B-cell chronic lymphocytic leukaemia (CLL) and other lymphoproliferative disorders was investigated. Granulocyte-binding IgG was measured in 34 patients with CLL, 13 patients with hairy cell leukaemia, one patient with prolymphocytic leukaemia, two patients with Sézary cell leukaemia, and seven patients with chronic T-cell lymphocytosis who had a predominance of circulating large granular lymphocytes. Anti-granulocyte activity was absent in CLL and its variants, but present in the majority of granulocytopenic patients with chronic T-cell lymphocytosis. In one of these patients, granulocytopenia was associated with complement-activating IgG granulocyte antibody. Thus, antibody-mediated granulocyte injury appears to be an unusual occurrence in chronic lymphocytic leukaemia, but is a frequent complication of chronic T-cell lymphocytosis. 相似文献
12.
Human papillomavirus genotype distribution in low-grade cervical lesions: comparison by geographic region and with cervical cancer. 总被引:13,自引:0,他引:13
Gary M Clifford Rashida K Rana Silvia Franceschi Jennifer S Smith Gerald Gough Jeanne M Pimenta 《Cancer epidemiology, biomarkers & prevention》2005,14(5):1157-1164
Low-grade squamous intraepithelial lesions (LSIL) associated with certain human papillomavirus (HPV) genotypes may preferentially progress to cervical cancer. HPV genotyping may thus have the potential to improve the effectiveness of screening programs and to reduce overtreatment. LSIL cases (n = 8,308) from 55 published studies were included in a meta-analysis. HPV genotype distribution was assessed by geographic region and in comparison with published data on cervical squamous cell carcinoma (SCC). HPV detection in LSIL was 80% in North America but less than 70% in other regions, most likely reflecting regional differences in LSIL diagnosis. Among 5,910 HPV-positive LSILs, HPV16 was the most common genotype (26.3%) followed by HPV31 (11.5%), HPV51 (10.6%), and HPV53 (10.2%). HPV-positive LSILs from Africa were 2-fold less likely to be infected with HPV16 than those in Europe, and HPV-positive LSILs from North America were more likely to be infected with HPV18 than those from Europe or South/Central America. Interpretation for rarer genotypes was hampered by variation in HPV testing methodology. SCC/LSIL prevalence ratios indicated that HPV16 was 2-fold and HPV18 was 1.5-fold more common in SCC than in HPV-positive LSIL, thus appearing more likely to progress than other high-risk genotypes (SCC/LSIL prevalence ratios between 0.05 and 0.85). HPV53 and HPV66 showed SCC/LSIL ratios of 0.02 and 0.01, respectively. HPV genotype distribution in LSIL differs from that in cervical cancer, highlighting the importance of HPV genotype in the risk of progression from LSIL to malignancy. Some regional differences in the relative importance of HPV genotypes in LSIL were noted. 相似文献
13.
Walter S Speidl Markus Exner Jasmin Amighi Wolfgang Mlekusch Schila Sabeti Stefan P Kastl Gerlinde Zorn Gerald Maurer Oswald Wagner Kurt Huber Erich Minar Johann Wojta Martin Schillinger 《Journal of endovascular therapy》2007,14(1):62-69
PURPOSE: To investigate whether balloon angioplasty of the superficial femoral artery (SFA) increases serum levels of C5a and whether C5a predicts risk of restenosis. METHODS: C5a antigen was measured at baseline and 8 hours after intervention in 131 consecutive patients (76 women; median age 72 years) with intermittent claudication who underwent successful primary SFA balloon angioplasty. Patients were followed for a median 10 months [interquartile range (IQR) 6 to 14] for the occurrence of >50% restenosis by duplex ultrasound. RESULTS: Median C5a levels increased significantly from 39.7 ng/mL (IQR 27.8 to 55.0) at baseline to 53.8 ng/mL (IQR 35.6 to 85.1, p<0.001) 8 hours post intervention. During the follow-up period, 70 (53%) patients developed restenosis. Increasing levels of C5a (quartiles) at baseline were significantly associated with an increased risk for restenosis (p=0.0092). Adjusted hazard ratios (95% confidence intervals) for restenosis with increasing quartiles of baseline serum C5a levels were 1.24 (0.60 to 2.58), 1.93 (0.95 to 3.93), and 2.08 (1.02 to 4.21), respectively, compared to the lowest quartile. This effect was independent of nonspecific inflammation as reflected by plasma levels of C-reactive protein. CONCLUSION: Inflammatory mechanisms play a major role in the development of restenosis after angioplasty. The complement component C5a exerts strong chemotactic and proinflammatory effects. Enhanced complement activation prior to PTA, as measured by higher levels of C5a, was significantly associated with restenosis after SFA balloon angioplasty. Pathways of complement inhibition thus may be worth investigating with respect to improving patency rates. 相似文献
14.
Katie S Lekx Maryam Fathimani Yves Bureau Gerald Wisenberg Jane Sykes Frank S Prato 《Journal of cardiovascular magnetic resonance》2006,8(5):731-739
PURPOSE: To evaluate qualitative wall motion assessment vs. quantitative wall thickening for the assessment of subtle changes in myocardial systolic function using cine MRI. METHODS: Cine MR images were obtained in 5 canines with a significant coronary artery stenosis and in 2 controls on a 1.5T scanner. Qualitative results were obtained using a numerical scoring system; quantitative analysis was performed using a semi-automatic segmentation program. The techniques were matched and compared using Spearman correlations. RESULTS: All correlations in the experimental group revealed significant but weak to moderate relationships between the qualitative and quantitative results (e.g., at-risk tissue rho = 0.363, p < 0.0001; remote tissue rho = 0.275, p = 0.0002), with each identifying changes in regional function that ensued following creation of the stenosis. Intra-observer variability was reasonable in both methods when repeat analysis on a subset of the data was performed, with both techniques showing a significant correlation between the repeated measurements (quantitative - rho = 0.52, p < 0.0001; qualitative - rho = 0.54, p < 0.0001). CONCLUSION: Both methods were able to detect very limited wall motion abnormalities present in the canines with significant stenosis and either method gives comparable results. 相似文献
15.
16.
Gerald Westheimer 《Optometry and vision science》2003,80(11):745-748
When the contrast polarity of a visual acuity chart is reversed by using bright letters on a dark background instead of dark on light, the shape and height of the resolution feature in the retinal image is identical but inverted compared with the normal situation. However, the contrast is different in the two cases because the background light level, which is a dividing factor when contrast is calculated, is much less when only the letters are bright. To the extent that contrast is a limiting factor in visual acuity, reversed-contrast acuity would be expected to be better, and proportionally more so in eyes where light scatter and aberrations widen and flatten the point-spread function. In a careful psychophysical study of Landolt C resolution, the minimum angle of resolution was found to be significantly smaller for white letters on a dark background than for the traditional dark on bright situation. 相似文献
17.
18.
19.
Gerald Klose 《Medizinische Klinik》2005,2(4):99-106
Eine 71-jährige, gesundheitsbewusste, zu einer Medizinerfamilie gehörige Patientin stellt sich zur Bewertung einer seit 10 Jahren bekannten Cholesterinerhöhung und der an anderer Stelle begonnenen Behandlung mit Mevinacor® (Lovastatin) vor.Im vorausgegangenen Jahr waren bei vielen Gelegenheiten Gesamtcholesterinkonzentrationen zwischen 289 und 345 mg/dl bestimmt worden. LDL wurde bis auf maximal 261 mg/dl erhöht gefunden, die HDL-Cholesterin-Werte lagen zwischen 40 und 48 mg/dl, die Triglyzeride zwischen 99 und 264 mg/dl. 相似文献
20.
Gerald A. Beathard 《Seminars in dialysis》1995,8(4):241-242
A substantial fraction of clotted polytetrafluoroethylene (PTFE) grafts undergoing thrombolysis and angioplasty clot again within a few months. Is there a place for routine follow-up fistulograms in these patients, or should we just retreat them as needed? Is there, perhaps, a subgroup that requires special management? 相似文献