全文获取类型
收费全文 | 37188篇 |
免费 | 4130篇 |
国内免费 | 2742篇 |
专业分类
耳鼻咽喉 | 223篇 |
儿科学 | 391篇 |
妇产科学 | 317篇 |
基础医学 | 4219篇 |
口腔科学 | 667篇 |
临床医学 | 5061篇 |
内科学 | 5156篇 |
皮肤病学 | 337篇 |
神经病学 | 1923篇 |
特种医学 | 1557篇 |
外国民族医学 | 19篇 |
外科学 | 3636篇 |
综合类 | 7058篇 |
现状与发展 | 14篇 |
一般理论 | 4篇 |
预防医学 | 2764篇 |
眼科学 | 995篇 |
药学 | 4176篇 |
57篇 | |
中国医学 | 2604篇 |
肿瘤学 | 2882篇 |
出版年
2024年 | 203篇 |
2023年 | 758篇 |
2022年 | 1946篇 |
2021年 | 2374篇 |
2020年 | 1833篇 |
2019年 | 1527篇 |
2018年 | 1489篇 |
2017年 | 1373篇 |
2016年 | 1248篇 |
2015年 | 1804篇 |
2014年 | 2276篇 |
2013年 | 2141篇 |
2012年 | 3045篇 |
2011年 | 3126篇 |
2010年 | 2056篇 |
2009年 | 1638篇 |
2008年 | 1953篇 |
2007年 | 1883篇 |
2006年 | 1744篇 |
2005年 | 1650篇 |
2004年 | 1037篇 |
2003年 | 1088篇 |
2002年 | 976篇 |
2001年 | 755篇 |
2000年 | 737篇 |
1999年 | 685篇 |
1998年 | 443篇 |
1997年 | 449篇 |
1996年 | 292篇 |
1995年 | 284篇 |
1994年 | 254篇 |
1993年 | 172篇 |
1992年 | 166篇 |
1991年 | 160篇 |
1990年 | 107篇 |
1989年 | 85篇 |
1988年 | 99篇 |
1987年 | 68篇 |
1986年 | 36篇 |
1985年 | 26篇 |
1984年 | 22篇 |
1983年 | 13篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1972年 | 3篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
J. Pepke-Zaba T. W. Higenbottam A. T. Dinh Xuan J. P. Scott T. A. H. English J. Wallwork 《Transplant international》1990,3(1):108-112
Abstract. Twenty-one patients were studied at rest and during exercise after heart transplantation to compare cardiac output measured by thermodilution and impedance cardiography. Exercise was performed on a bicycle ergometer over a limited range of work load (25 and 50 watt) whilst metabolic gas exchange was recorded. One patient was studied at rest whilst his circulation was maintained by a Jarvik-7 artificial heart. The values of cardiac output measured by impedance cardiography corresponded closely with the flow rate from the artificial heart. There was also close agreement between the impedance and thermodilution measurements of cardiac output at rest and during exercise. Both measurements followed the changes in heart rate and oxygen consumption. Both thermodilution and impedance cardiography methods elicited good reproducibility of cardiac output measurements at rest and during exercise. These observations suggest that the noninvasive and continuous record of cardiac output obtained by impedance cardiography can be used for the postoperative monitoring of heart transplant recipients. 相似文献
22.
大鼠肝细胞Ⅰ,Ⅲ型前胶原基因表达及PDGF的影响 总被引:3,自引:1,他引:2
目的观察大鼠肝细胞Ⅰ,Ⅲ型前胶原基因的表达及PDGF对其表达的影响.方法应用原位杂交技术检测分离培养的SD大鼠肝细胞(n=30)内Ⅰ,Ⅲ型前胶原基因的表达.同时观察10μg/L(n=30)和30μg/L(n=30)PDGF促进前胶原基因表达的作用.测定基因表达颗粒总面积占细胞总面积的百分比,并作比较分析.结果无论正常肝细胞或是在两种浓度的PDGF存在时,肝细胞内均可见到Ⅰ,Ⅲ型前胶原基因的表达.正常肝细胞Ⅰ,Ⅲ型前胶原基因表达面积的百分比(%)为77±19和75±21;加10μg/LPDGF后为115±19和112±10,而加30μg/L后为152±34及181±28,且在后者中表达明显增强(P<005及P<001).结论PDGF在转录水平上促进肝细胞胶原的合成. 相似文献
23.
正常闪光视网膜电图的频域分析 总被引:3,自引:0,他引:3
应用快速傅里叶转换技术对正常视网膜电图进行频域分析,发现其a、b波的优势频及能量集中在5-75Hz;与OPS波的分离点为77HZ,从而提出单纯记录a、b波及OPS波各自的较理想的通频带。 相似文献
24.
25.
PURPOSE: Little is known about use and expenditure patterns of children's eye-care services and about possible disparities in care among children. This report describes the use and expenditure patterns of eye care and non-eye care services for children under 18 years old in the United States. METHODS: Levels of use and expenditure were estimated using self-reported information from the nationally representative Medical Expenditure Panel Surveys (1996-2001) for 48,304 subjects under 18 years old from randomly selected households in the United States. Means presented for children with and without diagnosed eye conditions were adjusted for child and family characteristics using generalized linear models. RESULTS: Children with diagnosed eye conditions had higher levels of use and expenditure than children without diagnosed conditions. Families of children with diagnosed eye conditions incurred higher out-of-pocket expenditures. Black children and children living below 400% of the federal poverty level had lower levels of use and expenditure, indicating that they received fewer and less intensive services. CONCLUSIONS: Children with diagnosed eye conditions experienced higher overall use of health care. Some groups of children appear to be underserved. Estimates of use and expenditure patterns, stratified by socioeconomic factors, will be needed to plan for future delivery of children's eye and vision care services and to assess progress toward Healthy People 2010 goals. 相似文献
26.
目的:了解细菌性阴道病在延边地区出国务工妇女中的流行情况。方法:用改良多胺法对延边地区586名出国务工妇女进行细菌性阴道病(BV)检测,同时用常规方法进行滴虫、霉菌检查。结果:586份阴道分泌物标本中,检出BV(+)275例,总阳性率为46.9%,其中单纯BV(+)242例(41.3%)、BV合并滴虫(+)8例(1.3%)、BV合并霉菌(+)25例(4.3%);按年龄分组,33~35岁组BV阳性率最高,为60.3%,≤20岁组最低,为20.0%。结论:延边地区出国务工妇女细菌性阴道病患病率较高,居该人群各种阴道感染的首位,无民族差异(χ2=0.22,P>0.05),但年龄差异显著(χ2=28.72,P<0.05)。因此,建议在出国体检中常规开展BV检查,以便及时发现和治疗,控制疾病传播范围。 相似文献
27.
食管癌三维适形后程加速超分割放射治疗的疗效分析 总被引:3,自引:0,他引:3
目的评价三维适形后程加速超分割放射治疗食管癌的疗效及放疗反应、并发症。方法2002年2月至2004年5月,71例食管鳞癌随机分成两组,三维适形后程加速超分割组36例,食管病变上下外约4cm,前后、左右外约0.5~1cm作为PTV1,每次2GY,每周5次,DT40GY后,病变上下外约2cm,前后、左右外约0.5~1cm作为PTV2,每日2次,每次1.5GY,间隔4~6小时,总疗程6周,总剂量67GY/38次。非三维适形后程加速超分割组35例,时间、剂量、分割方式同适形组。所有病例均采用8MV-X外照射。结果1、2、3年的生存率和原发肿瘤的局控率,与非适形后程加速超分割比较,适形组明显提高,分别为88.9%、75%、63.9%比68.6%、51.4%、40%和86.1%、72.2%、58.3%比65.7%、48.5%、34.3%。适形组的急性放射反应明显低于非适形后程加速超分割组,两组有显著差别。结论本研究的初步结果表明食管癌适形后程加速超分割放射治疗的疗效优于非适形后程加速超分割组。 相似文献
28.
Noriyo Kimura Satomi Yonemoto Toshihiko Machiguchi Xuan Li Hideki Kimura Haruyoshi Yoshida 《Hypertension research》2006,29(8):573-580
The major glomerular abnormalities in hypertensive nephrosclerosis are described as glomerular obsolescence (GO), glomerulosclerosis (GS), and glomerular collapse (GC). However, glomerular cellular changes caused by hypertensive insults have not been well analyzed. Using an immunoenzyme method, we examined eleven biopsy samples from patients with hypertensive nephrosclerosis for two synthetic and secreting phenotypes, a-smooth muscle actin (alpha-SMA) and collagen type III (Col. III), and two apoptotic phenotypes, pro-apoptotic molecule Bax and anti-apoptotic molecule BcI-2. Together with the glomerular and vascular changes and interstitial fibrosis (IF) area, the results were scored quantitatively and semi-quantitatively and compared to the clinical findings, which included systolic blood pressure (SBP), mean arterial pressure (MAP), serum creatinine levels (sCr) and creatinine clearance (Ccr), using univariate and multivariate analyses. As a result, GS was frequently observed in the mild-to-moderate hypertensive group (140 < or = SBP<180 mmHg), whereas GC was positively correlated with SBP. Furthermore, there was a positive correlation of GS with mesangial alpha-SMA and Col. III, suggesting that GS was the reflection of these synthetic and secreting phenotypic changes in mesangial cells. Endothelial Bax was positively correlated with Ccr (p<0.01); in contrast, podocytic Bax was positively correlated with sCr (p<0.05) and showed a tendency to correlate with MAP (p=0.054). In conclusion, these findings support the view that mesangial synthetic and secreting phenotypic changes may be a reflection of cellular activation caused by mild-to-moderate hypertension and that apoptotic phenotypic expression in podocytes, rather than endothelial cells, may be related to the development of a severe form of hypertensive nephrosclerosis. 相似文献
29.
In this study, an animal model of multiple system organ failure (MSOF) in rabbits, engendered by feeding E. coli prior to severe hemorrhagic shock, was used for the purpose of investigating 1) the relationship between lipopolysaccharide (LPS) and MSOF, and 2) the effectiveness of Re-LPS antiserum in preventing MSOF. The results showed that endotoxemia occurred very early, and its degree correlated well with that of organ dysfunction. Re-LPS antiserum administration abated the toxic effects and lowered the incidence of MSOF. These results suggest that sequential analysis of circulating LPS levels may be useful for the early diagnosis of MSOF, and that gut-derived endotoxin might play an important role in the pathogenesis of experimental MSOF. 相似文献
30.