全文获取类型
收费全文 | 3807篇 |
免费 | 216篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 222篇 |
妇产科学 | 86篇 |
基础医学 | 490篇 |
口腔科学 | 47篇 |
临床医学 | 318篇 |
内科学 | 781篇 |
皮肤病学 | 127篇 |
神经病学 | 185篇 |
特种医学 | 212篇 |
外科学 | 353篇 |
综合类 | 243篇 |
预防医学 | 320篇 |
眼科学 | 72篇 |
药学 | 288篇 |
中国医学 | 47篇 |
肿瘤学 | 218篇 |
出版年
2023年 | 23篇 |
2022年 | 53篇 |
2021年 | 110篇 |
2020年 | 55篇 |
2019年 | 48篇 |
2018年 | 80篇 |
2017年 | 56篇 |
2016年 | 76篇 |
2015年 | 95篇 |
2014年 | 130篇 |
2013年 | 185篇 |
2012年 | 196篇 |
2011年 | 227篇 |
2010年 | 165篇 |
2009年 | 117篇 |
2008年 | 166篇 |
2007年 | 199篇 |
2006年 | 176篇 |
2005年 | 149篇 |
2004年 | 110篇 |
2003年 | 111篇 |
2002年 | 95篇 |
2001年 | 102篇 |
2000年 | 99篇 |
1999年 | 76篇 |
1998年 | 67篇 |
1997年 | 59篇 |
1996年 | 62篇 |
1995年 | 47篇 |
1994年 | 39篇 |
1993年 | 52篇 |
1992年 | 48篇 |
1991年 | 52篇 |
1990年 | 56篇 |
1989年 | 82篇 |
1988年 | 58篇 |
1987年 | 47篇 |
1986年 | 39篇 |
1985年 | 34篇 |
1984年 | 24篇 |
1983年 | 21篇 |
1982年 | 17篇 |
1979年 | 26篇 |
1978年 | 17篇 |
1977年 | 18篇 |
1975年 | 19篇 |
1973年 | 25篇 |
1971年 | 19篇 |
1970年 | 19篇 |
1969年 | 20篇 |
排序方式: 共有4056条查询结果,搜索用时 15 毫秒
101.
102.
Amplification of genes encoding human myeloid membrane antigens after DNA-mediated gene transfer 总被引:2,自引:0,他引:2
Spontaneous amplification of genes encoding two different human myeloid surface antigens was observed after DNA-mediated gene transfer of cellular DNA from the human myeloid cell line HL-60 into NIH-3T3 mouse fibroblasts. Transformed recipient cells with highly amplified expression of either of two donor membrane polypeptides, gp150 or p67, were isolated with a fluorescence-activated cell sorter (FACS), using monoclonal antibodies specific for human myeloid cells. Immunoprecipitation of enzymatically radioiodinated polypeptides from the surface of transformed NIH-3T3 cells confirmed that expression of these proteins was amplified tenfold to 20-fold in comparison to their expression on human myeloid cell lines. The cellular DNA of cloned secondary and tertiary transformants expressing high levels of gp150 and p67 contained amplified sets of DNA restriction fragments that hybridized with human repetitive DNA sequences. Cytogenetic analysis of subclones overexpressing gp150 revealed extrachromosomal double minutes (DMs), whose presence correlated with the unstable expression of the membrane polypeptide. Human sequences in gp150-positive clones did not localize to chromosomes, consistent with their association with extrachromosomal DMs. By contrast, p67-positive subclones stably expressed the antigen, and in situ hybridization to metaphase spreads demonstrated that amplified human DNA sequences were integrated into a specific marker chromosome. Cytogenetic analysis of the parental NIH- 3T3 subclone used in these studies disclosed DMs in a low percentage of metaphases, suggesting that the recipient cells have a propensity for amplifying donor DNA. 相似文献
103.
104.
T H Marwick A Lafont R T Go D A Underwood G B Saha W J MacIntyre 《International journal of cardiology》1992,35(1):33-41
Current techniques for the detection of recurrent coronary stenoses following bypass grafting have shown disappointing diagnostic accuracy. This study used the same dipyridamole-handgrip stress to compare the accuracy of rubidium-82 positron emission tomography and thallium-201 single photon emission computed tomography, in 50 consecutive post-bypass patients undergoing coronary arteriography at a mean interval of 6.5 years after surgery. Significant stenoses in native coronary vessels (greater than 50% diameter) or grafts (greater than 70% diameter) were defined by quantitative angiography. Forty-six patients had recurrent or residual stenoses, 43 (93%) had a perfusion defect identified by positron emission tomography, and 35 (76%) were identified by single photon emission computed tomography (P = 0.04). Fourteen of the 17 patients (82%) without previous Q-wave myocardial infarction were identified by positron emission tomography; 10 of the 17 (59%) were detected by single photon emission computed tomography (P = NS). Stress-induced perfusion defects were demonstrated by positron emission tomography in 19 patients; of this group, thallium imaging identified reversible defects in 11, showed no perfusion defect in 1, and portrayed a persistent defect in 7 patients. Significant graft disease was present in 33 patients; perfusion defects were identified by positron emission tomography in 30 (91%), and by single photon emission computed tomography in 24 (73%, P = NS). Four patients were fully revascularized, without significant recurrent coronary disease; normal perfusion was present in 3 (75%) by positron emission tomography, and 4 (100%) by single photon emission computed tomography.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
105.
Homocysteine and carotid atherosclerosis in chronic renal failure--the confounding effect of renal function 总被引:4,自引:0,他引:4
Leskinen Y Lehtimäki T Loimaala A Huhtala H Salenius JP Oja SS Saha H 《Atherosclerosis》2004,175(2):315-323
Since total homocysteine (tHcy) level is markedly elevated in patients with chronic renal failure (CRF), it has been presented as a potential factor contributing to the high risk of cardiovascular disease (CVD) in CRF. Our aim was to examine the significance of elevated tHcy level and other cardiovascular risk factors for carotid atherosclerosis in patients with CRF. In this cross-sectional study, 135 study patients with CRF (52 +/- 11 years) included 58 patients with moderate to severe predialysis CRF, 36 dialysis patients and 41 renal transplant recipients. In addition, 58 control subjects were examined. The association of tHcy level and classic risk factors for atherosclerosis with common carotid artery intima-media thickness (IMT) or carotid artery plaque score was examined. We found no association between tHcy and carotid IMT or a high carotid plaque score in the CRF patient groups. No consistent association was found between elevated tHcy and coronary artery disease, cerebrovascular disease or peripheral arterial disease. Renal function, described as creatinine clearance, was the strongest determinant for tHcy level. Significant predictors of carotid atherosclerosis were age, duration of hypertension and elevated low-density lipoprotein cholesterol level. In conclusion, the present study shows no apparent association between tHcy level and atheromatous carotid findings in patients with CRF. However, because of the changing renal function in the course of renal disease, the strong confounding effect of renal function may not be adequately controlled for the analysis of the significance of elevated tHcy level for CVD in patients with CRF. 相似文献
106.
Ganguly S Das NK Panja M Pal S Modak D Rahaman M Mallik S Guha SK Pramanik N Goswami R Barbhuiya JN Saha B Chatterjee M 《The Journal of infectious diseases》2008,197(12):1762-1771
BACKGROUND: Post-kala-azar dermal leishmaniasis (PKDL), an established sequela of visceral leishmaniasis (VL), is proposed to facilitate anthroponotic transmission of VL, especially during interepidemic periods. Immunopathological mechanisms responsible for Indian PKDL are still poorly defined. METHODS: Our study attempted to characterize the immune profiles of patients with PKDL or VL relative to that of healthy control subjects by immunophenotyping, intracellular cytokine staining of peripheral blood mononuclear cells, and enzyme-linked immunosorbent assay for serum cytokines and immunoglobulin G (IgG) subclasses. RESULTS: Patients with PKDL had significantly raised percentages of peripheral CD3+CD8+ cells compared with control subjects, a difference that persisted after cure. Patients with PKDL showed an intact response to phytohemagglutinin, with the percentages of lymphocytes expressing interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10 being comparable to those in control subjects. Patients with VL had decreased IFN-gamma and IL-2 expression, which was restored after cure, and increased IL-10 expression, which persisted after cure. In their response to Leishmania donovani antigen, patients with PKDL showed a 9.6-fold increase in the percentage of IL-10-expressing CD3+CD8+ lymphocytes compared with control subjects, and this percentage decreased with treatment. Patients with PKDL had raised levels of IgG3 and IgG1 (surrogate markers for IL-10), concomitant with increased serum levels of IL-10. CONCLUSIONS: IL-10-producing CD3+CD8+ lymphocytes are important protagonists in the immunopathogenesis of Indian PKDL. 相似文献
107.
108.
Minireview: malonyl CoA, AMP-activated protein kinase, and adiposity 总被引:14,自引:0,他引:14
109.
Ashish Correa Achint Patel Kinsuk Chauhan Harshil Shah Aparna Saha Mihir Dave Priti Poojary Abhishek Mishra Narender Annapureddy Shaman Dalal Ioannis Konstantinidis Renu Nimma Shiv Kumar Agarwal Lili Chan Girish Nadkarni Sean Pinney 《Journal of cardiac failure》2018,24(7):442-450
Background
Dialysis-requiring acute kidney injury (D-AKI) is a serious complication in hospitalized heart failure (HF) patients. However, data on national trends are lacking after 2002.Methods
We used the Nationwide Inpatient Sample (2002–2013) to identify HF hospitalizations with and without D-AKI. We analyzed trends in incidence, in-hospital mortality, length of stay (LoS), and cost. We calculated adjusted odds ratios (aORs) for predictors of D-AKI and for outcomes including in-hospital mortality and adverse discharge (discharge to skilled nursing facilities, nursing homes, etc).Results
We identified 11,205,743 HF hospitalizations. Across 2002–2013, the incidence of D-AKI doubled from 0.51% to 1.09%. We found male sex, younger age, African-American and Hispanic race, and various comorbidities and procedures, such as sepsis and mechanical ventilation, to be independent predictors of D-AKI in HF hospitalizations. D-AKI was associated with higher odds of in-hospital mortality (aOR 2.49, 95% confidence interval [CI] 2.36–2.63; P?<?.01) and adverse discharge (aOR 2.04, 95% CI 1.95–2.13; P?<?.01). In-hospital mortality and attributable risk of mortality due to D-AKI decreased across 2002–2013. LoS and cost also decreased across this period.Conclusions
The incidence of D-AKI in HF hospitalizations doubled across 2002–2013. Despite declining in-hospital mortality, LoS, and cost, D-AKI was associated with worse outcomes. 相似文献110.