全文获取类型
收费全文 | 76838篇 |
免费 | 5992篇 |
国内免费 | 2572篇 |
专业分类
耳鼻咽喉 | 1095篇 |
儿科学 | 1149篇 |
妇产科学 | 1067篇 |
基础医学 | 10133篇 |
口腔科学 | 1845篇 |
临床医学 | 8184篇 |
内科学 | 12480篇 |
皮肤病学 | 1703篇 |
神经病学 | 4607篇 |
特种医学 | 3585篇 |
外国民族医学 | 7篇 |
外科学 | 8215篇 |
综合类 | 7507篇 |
现状与发展 | 14篇 |
一般理论 | 10篇 |
预防医学 | 5342篇 |
眼科学 | 1541篇 |
药学 | 7945篇 |
36篇 | |
中国医学 | 3245篇 |
肿瘤学 | 5692篇 |
出版年
2024年 | 170篇 |
2023年 | 767篇 |
2022年 | 2157篇 |
2021年 | 3144篇 |
2020年 | 2064篇 |
2019年 | 2144篇 |
2018年 | 2405篇 |
2017年 | 2177篇 |
2016年 | 2492篇 |
2015年 | 3646篇 |
2014年 | 4181篇 |
2013年 | 4912篇 |
2012年 | 6945篇 |
2011年 | 6961篇 |
2010年 | 4640篇 |
2009年 | 3718篇 |
2008年 | 4753篇 |
2007年 | 4439篇 |
2006年 | 3962篇 |
2005年 | 3538篇 |
2004年 | 2845篇 |
2003年 | 2602篇 |
2002年 | 2216篇 |
2001年 | 1643篇 |
2000年 | 1351篇 |
1999年 | 955篇 |
1998年 | 465篇 |
1997年 | 380篇 |
1996年 | 274篇 |
1995年 | 250篇 |
1994年 | 226篇 |
1993年 | 175篇 |
1992年 | 304篇 |
1991年 | 284篇 |
1990年 | 237篇 |
1989年 | 221篇 |
1988年 | 187篇 |
1987年 | 158篇 |
1986年 | 146篇 |
1985年 | 121篇 |
1984年 | 79篇 |
1983年 | 73篇 |
1982年 | 48篇 |
1979年 | 87篇 |
1978年 | 56篇 |
1975年 | 67篇 |
1974年 | 47篇 |
1972年 | 49篇 |
1971年 | 59篇 |
1970年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Su SC Chou SS Chang PC Hwang DF 《Journal of chromatography. B, Biomedical sciences and applications》2000,749(2):163-169
A micellar electrokinetic capillary chromatography (MECC) method for the simultaneous determination of seven biogenic amines in fish was developed. The peaks of all components were successfully separated within 11.5 min. MECC was performed with 0.06 M sodium deoxycholate in 0.02 M borate buffer (pH 9.2)-methanol (95:5, v/v) solvent. The average recoveries for all components ranged from 84.4 to 100.3%. The application of this method to detect amines in fried marlin fillet implicated in a food poisoning incident indicated that a high level (56.24 mg/100 g) of histamine was present in the sample. Another 10 fish samples collected from markets were also analyzed and did not contain detectable levels of histamine (<2.5 mg/100 g). 相似文献
102.
H. Kiesewetter F. Jung J. Blume B. Bulling R. P. Franke 《Journal of molecular medicine (Berlin, Germany)》1986,64(1):29-37
Summary Rheological therapy, as an immediate treatment in conjunction with physical therapy and the removal of risc factors, plays a significant role in the management of patients with peripheral vascular disease experiencing reduced walking tolerance. An essential element of rheological therapy is hemodilution. Currently, is still uncertain which plasma substitute solution would be the most appropriate in such cases. This study compared the effectiveness of low molecular hydroxyethyl starch to low molecular dextran during a 16-day hemodilution in combination to physical therapy. The clinical improvement observed with both plasma substitute solutions was comparable, yet in view of the cardiac volume overload, dextran demonstrates greater circulatory stress due to the transient pressure increase and more side effects. For this reason, we prefer to administer low or middle molecular hydroxyethyl starch in the dilution treatment of peripheral arterial occlusive disease as a chronic degenerative vascular disease.
Abkürzungen A2M Alpha-2-Makroglobulin - D0 Meßzeitpunkt 0 der später mit Dextran behandelten Gruppe - D1 Meßzeitpunkt 1 der Dextran-Gruppe - D2 Meßzeitpunkt 2 der Dextran-Gruppe - Dextran 40 kleinmolekulares Dextran (mittleres Molekulargewicht 40000 Dalton) - ETA Plasmaviskosität - Fib Fibrinogen - Geh Gehstrecke - H0 Meßzeitpunkt 0 der später mit Hydroxyäthylstärke behandelten Gruppe - H1 Meßzeitpunkt 1 der HAES-Gruppe - H2 Meßzeitpunkt 2 der HAES-Gruppe - HAES 40 kleinmolekulare Hydroxyäthylstärke (mittleres Molekulargewicht 40000 Dalton) - Hkt Hämatokrit - LZ Leukozyten-Zahl - Pro Gesamteiweiß - SEA Erythrozyten-Aggregationsindex - SER Erythrozyten-Rigiditätsindex - TY Fließschubspannung - TZ Thrombozyten-Zahl 相似文献
Abkürzungen A2M Alpha-2-Makroglobulin - D0 Meßzeitpunkt 0 der später mit Dextran behandelten Gruppe - D1 Meßzeitpunkt 1 der Dextran-Gruppe - D2 Meßzeitpunkt 2 der Dextran-Gruppe - Dextran 40 kleinmolekulares Dextran (mittleres Molekulargewicht 40000 Dalton) - ETA Plasmaviskosität - Fib Fibrinogen - Geh Gehstrecke - H0 Meßzeitpunkt 0 der später mit Hydroxyäthylstärke behandelten Gruppe - H1 Meßzeitpunkt 1 der HAES-Gruppe - H2 Meßzeitpunkt 2 der HAES-Gruppe - HAES 40 kleinmolekulare Hydroxyäthylstärke (mittleres Molekulargewicht 40000 Dalton) - Hkt Hämatokrit - LZ Leukozyten-Zahl - Pro Gesamteiweiß - SEA Erythrozyten-Aggregationsindex - SER Erythrozyten-Rigiditätsindex - TY Fließschubspannung - TZ Thrombozyten-Zahl 相似文献
103.
Lee JK Kim JH Kim JS Kim TS Jung S Kim SH Kang SS Lee JH 《Journal of Korean medical science》2001,16(4):532-536
Amenorrhea is rarely presented as a manifestation of endocrinological disturbances in patients of chronic hydrocephalus. We describe two cases of secondary amenorrhea caused by hydrocephalus due to aqueductal stenosis. Two female patients of age 30 and 20 yr presented with amenorrhea and increasing headache. Magnetic resonance images revealed marked, noncommunicating hydrocephalus without any tumorous lesion. In one patient, emergent extraventricular drainage was necessary because of progressive neurological deterioration. Each patient underwent surgical intervention for the hydrocephalus-ventriculoperitoneal shunt and endoscopic third ventriculostomy. Both resumed normal menstruation continuing so far with further normal menstrual bleeding. These two cases and others reported in the literature indicated that the surgical intervention for hydrocephalus resolves amenorrhea in all the cases of amenorrhea due to hydrocephalus. The suspected role of the surgery is the correction of increased intracranial pressure, which is an important pathogenetic factor in the development of amenorrhea. 相似文献
104.
本文研究丁敌枯双对BALB/C雄性小鼠生殖细胞分裂比率及精原细胞染色体畸变的影响。将实验小鼠随机分为三组,即实验组(敌枯双组),阳性对照组(环磷酰胺组)和阴性对照组(双蒸水组)。结果发现:敌枯双能明显诱发精原细胞多倍体率和裂隙率增加,抑制终变期/中期Ⅰ和中期Ⅱ细胞的减数分裂比率,促进精原细胞有丝分裂比率。实验结果还提示:在遗传毒理检测中亚急性实验是必要的,并对实验结果进行了初步讨论。 相似文献
105.
106.
Missing data such as appropriateness ratings in clinical research are a common problem and this often yields a biased result. This paper aims to introduce the multiple imputation method to handle missing data in clinical research and to suggest that the multiple imputation technique can give more accurate estimates than those of a complete-case analysis. The idea of multiple imputation is that each missing value is replaced with more than one plausible value. The appropriateness method was developed as a pragmatic solution to problem of trying to assess "appropriate" surgical and medical procedures for patients. Cataract surgery was selected as one of four procedures that were evaluated as a part of the Clinical Appropriateness Initiative. We created mild to high missing rates of 10%, 30% and 50% and compared the performance of logistic regression in cataract surgery. We treated the coefficients in the original data as true parameters and compared them with the other results. In the mild missing rate (10%), the deviation from the true coefficients was quite small and ignorable. After removing the missing data, the complete-case analysis did not reveal any serious bias. However, as the missing rate increased, the bias was not ignorable and it distorted the result. This simulation study suggests that a multiple imputation technique can give more accurate estimates than those of a complete-case analysis, especially for moderate to high missing rates (30 - 50%). In addition, the multiple imputation technique yields better accuracy than a single imputation technique. Therefore, multiple imputation is useful and efficient for a situation in clinical research where there is large amounts of missing data. 相似文献
107.
Cooperative transformation of murine fibroblast NIH3T3 cells by hepatitis C virus core protein and hepatitis B virus X protein 总被引:7,自引:0,他引:7
Co-infection with hepatitis B virus (HBV) and hepatitis C Virus (HCV) is associated with increased frequency in the development of hepatocellular carcinoma (HCC). Here, we demonstrated that HBV X protein (HBx) and HCV core cooperate to transform mouse fibroblast NIH3T3 cells. They additively stimulated cell growth, especially in the absence of serum growth factors. In addition, co-expression of HBx and HCV core had additive effects on the induction of anchorage-independent cell growth as well as on the secretion of matrix metalloproteases, which may contribute to increased metastatic potential. Furthermore, the cells expressing both viral proteins exhibited higher tumorigenicity, as demonstrated in athymic nude mice. 相似文献
108.
BACKGROUND: The skin of patients with atopic dermatitis (AD) exhibits a striking susceptibility to colonization and infection by Staphylococcus aureus. The exotoxins secreted by S. aureus can act as superantigens and classic allergens, inducing the production of functionally relevant specific IgE antibodies. The aim of this study was to compare the levels and positive rates of serum staphylococcal enterotoxin A (SEA)- and staphylococcal enterotoxin B (SEB)-specific IgE between atopic children with and without AD. METHODS: Sixty children with AD, 55 children with respiratory allergy without AD, and 24 nonatopic healthy children were studied. The levels and positive rates of serum SEA- and SEB-specific IgE were compared among three groups. The correlation between the levels or positive rates of serum SEA/SEB-specific IgE and the severity of AD or the presence of previous skin infections was studied. RESULTS: The children with AD had significantly higher levels and positive rates of serum SEA- and SEB-specific IgE than the atopic children without AD (P < 0.001) and the nonatopic children (P < 0.001). There was no significant difference in the levels and positive rates of serum SEA- and SEB-specific IgE between the atopic children without AD and the nonatopic children. With or without adjustment for the potential confounding effect of total serum IgE levels, the levels and positive rates of serum SEA- and SEB-specific IgE were significantly correlated with severity of AD (P <0.005), but they were not significantly different between AD children with and without previous skin infections. CONCLUSIONS: SEA and SEB may contribute to chronic inflammation and exacerbation of AD through the IgE-mediated immune response. 相似文献
109.
Lin Hui Eun-Seok Shin Eun Jung Jun Youngjune Bhak Scot Garg Tae-Hyun Kim Chang-Bae Sohn Byung Joo Choi Liu Kun Song Lin Yuan Wang Zhi Jiang Hao Shi Zhentao Tang Qiang 《Yonsei medical journal》2020,61(12):1004
PurposeDissection after plain balloon angioplasty is required to achieve adequate luminal area; however, it is associated with a high risk of vascular events. This study aimed to examine the relationship between non-flow limiting coronary dissections and subsequent lumen loss and long-term clinical outcomes following successful drug-coated balloon (DCB) treatment of de novo coronary lesions.Materials and MethodsA total of 227 patients with good distal flow (Thrombolysis in Myocardial Infarction flow grade 3) following DCB treatment were retrospectively enrolled and stratified according to the presence or absence of a non-flow limiting dissection. The primary endpoint was late lumen loss (LLL) at 6-month angiography, and the secondary endpoint was target vessel failure (TVF, a composite of cardiac death, target vessel myocardial infarction, target vessel revascularization, and target vessel thrombosis).ResultsThe cohort consisted of 95 patients with and 132 patients without a dissection. There were no between-group differences in LLL (90.8%) returning for angiography at 6 months (0.05±0.19 mm in non-dissection and 0.05±0.30 mm in dissection group, p=0.886) or in TVF (6.8% in non-dissection and 8.4% in dissection group, p=0.799) at a median follow-up of 3.4 years. In a multivariate analysis, the presence of dissection and its severity were not associated with LLL or TVF. Almost dissections (93.9%) were completely healed, and there was no newly developed dissection at 6-month angiography.ConclusionThe presence of a dissection following successful DCB treatment of a de novo coronary lesion may not be associated with an increased risk of LLL or TVF (Impact of Drug-coated Balloon Treatment in de Novo Coronary Lesion; ). NCT04619277相似文献
110.
Brazilin and haematoxylin, plant pigments, were examined for their effects on the Bovine-Lens aldose reductase (LAR)-activity. About 50% inhibition was observed in a concentration of 10 (-4) M-brazilin and 10 (-4) M-haematoxylin, and above 95% inhibition was observed in a concentration of 10 (-3) M-brazilin and 10 (-3)M-haematoxylin. In order to determine the type of inhibition, kinetic studies were also conducted with brazilin and haematoxylin, in which both were found to be noncompetitive inhibitors. 相似文献