全文获取类型
收费全文 | 2785298篇 |
免费 | 201255篇 |
国内免费 | 4290篇 |
专业分类
耳鼻咽喉 | 38137篇 |
儿科学 | 90623篇 |
妇产科学 | 74151篇 |
基础医学 | 412262篇 |
口腔科学 | 77252篇 |
临床医学 | 251603篇 |
内科学 | 537713篇 |
皮肤病学 | 61921篇 |
神经病学 | 216950篇 |
特种医学 | 103919篇 |
外国民族医学 | 552篇 |
外科学 | 417769篇 |
综合类 | 58076篇 |
现状与发展 | 12篇 |
一般理论 | 964篇 |
预防医学 | 215790篇 |
眼科学 | 65256篇 |
药学 | 208329篇 |
13篇 | |
中国医学 | 6216篇 |
肿瘤学 | 153335篇 |
出版年
2021年 | 22281篇 |
2019年 | 22729篇 |
2018年 | 31480篇 |
2017年 | 23761篇 |
2016年 | 26618篇 |
2015年 | 29962篇 |
2014年 | 42191篇 |
2013年 | 63365篇 |
2012年 | 86734篇 |
2011年 | 91868篇 |
2010年 | 54682篇 |
2009年 | 51677篇 |
2008年 | 86340篇 |
2007年 | 92046篇 |
2006年 | 93098篇 |
2005年 | 89774篇 |
2004年 | 86198篇 |
2003年 | 82718篇 |
2002年 | 80347篇 |
2001年 | 129460篇 |
2000年 | 132654篇 |
1999年 | 111243篇 |
1998年 | 31854篇 |
1997年 | 27819篇 |
1996年 | 28215篇 |
1995年 | 26727篇 |
1994年 | 24600篇 |
1993年 | 23133篇 |
1992年 | 85982篇 |
1991年 | 83925篇 |
1990年 | 81720篇 |
1989年 | 79105篇 |
1988年 | 72748篇 |
1987年 | 71262篇 |
1986年 | 66891篇 |
1985年 | 63828篇 |
1984年 | 47427篇 |
1983年 | 40285篇 |
1982年 | 23658篇 |
1979年 | 43591篇 |
1978年 | 30963篇 |
1977年 | 25855篇 |
1976年 | 24756篇 |
1975年 | 26635篇 |
1974年 | 31882篇 |
1973年 | 30441篇 |
1972年 | 28523篇 |
1971年 | 26935篇 |
1970年 | 25107篇 |
1969年 | 23739篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Accuracy and Precision of Acetabular Component Placement With Imageless Navigation in Obese Patients
Leonard T. Buller Alexander S. McLawhorn Jose A. Romero Peter K. Sculco David J. Mayman 《The Journal of arthroplasty》2019,34(4):693-699
Background
Obesity is a risk factor for acetabular component malposition when total hip arthroplasty is performed with manual techniques. The utility of imageless navigation in obese patients remains unknown. This study compared the accuracy and precision of imageless navigation for component orientation between obese and nonobese patients.Methods
A total of 459 total hip arthroplasties performed for osteoarthritis using imageless navigation were reviewed from a single surgeon’s institutional review board–approved database. Einzel-Bild-Roentgen Analyse determined component orientation on 6-week postoperative anteroposterior radiographs. Mean orientation error (accuracy) and precision were compared between obese (body mass index ≥ 30 kg/m2) and nonobese patients. Regression analysis evaluated the influence of obesity on component position.Results
The difference in mean inclination and anteversion between obese and nonobese groups was 1.1° (43.0° ± 3.5°; range, 35.8°-57.8° vs 41.9° ± 4.4°; range, 33.0°-57.1° and 24.9° ± 6.3°; range, 14.2°-44.3° vs 23.8° ± 6.6°; range, 7.0°-38.6°, respectively). Inclination precision was better for nonobese patients. No difference in inclination accuracy or anteversion accuracy or precision was detected between groups. And 83% of components were placed within the target range. There was no relationship between obesity (dichotomized) and component placement outside the target ranges for inclination, anteversion, or both. As a continuous variable, increased body mass index correlated with higher odds of inclination outside the target zone (odds ratio, 1.06; P = .001).Conclusion
Using imageless navigation, inclination orientation was less precise for obese patients, but the observed difference is likely not clinically relevant. Accurate superficial registration of landmarks in obese patients is achievable, and the use of imageless navigation similarly improves acetabular component positioning in obese and nonobese patients.Level of Evidence
Therapeutic Level IV. 相似文献12.
M. Iachina P.M. Ljungdalh R.G. Sørensen L. Kaerlev J. Blaakær O. Trosko N. Qvist B.M. Nørgård 《Clinical oncology (Royal College of Radiologists (Great Britain))》2019,31(2):115-123
Aims
To examine the influence of pre-existing psychiatric disorder on the choice of treatment in patients with gynaecological cancer.Materials and methods
The analyses were based on all patients who underwent surgical treatment for endometrial, ovarian or cervical cancer who were registered in the Danish Gynecological Cancer Database in the years 2007–2014 (3059 patients with ovarian cancer, 5100 patients with endometrial cancer and 1150 with cervical cancer). Logistic regression model and Cox regression model, adjusted for relevant confounders, were used to estimate the effect of pre-existing psychiatric disorder on the course of cancer treatment. Our outcomes were (i) presurgical oncological treatment, (ii) macroradical surgery for patients with ovarian cancer, (iii) radiation/chemotherapy within 30 days and 100 days after surgery and (iv) time from surgery to first oncological treatment.Results
In the group of patients with ovarian cancer, more patients with a psychiatric disorder received macroradical surgery versus patients without a psychiatric disorder, corresponding to an adjusted odds ratio of 1.24 (95% confidence interval 0.62–2.41) and the chance for having oncological treatment within 100 days was odds ratio = 1.26 (95% confidence interval 0.77–2.10). As for patients with endometrial cancer, all outcome estimates were close to unity. The adjusted odds ratio for oncological treatment within 30 days after surgery in patients with cervical cancer with a history of psychiatric disorder was 0.20 (95% confidence interval 0.03–1.54).Conclusions
We did not find any significant differences in the treatment of ovarian and endometrial cancer in patients with pre-existing psychiatric diagnoses. When it comes to oncological treatment, we suggest that increased attention should be paid to patients with cervical cancer having a pre-existing psychiatric diagnosis. 相似文献13.
14.
15.
16.
17.
18.
N. V. Bashmakova G. N. Chistiakova I. A. Gazieva Y. M. Trapeznikova D. O. Mazurov 《Gynecological endocrinology》2015,31(10):31-33
AbstractThis study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos. 相似文献
19.
J. Rodríguez-Carrio A. Martínez-Zapico I. Cabezas-Rodríguez L. Benavente Á.I. Pérez-Álvarez P. López J.B. Cannata-Andía M. Naves-Díaz A. Suárez 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(2):135-143
Background and aims
Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.Methods and results
In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.Conclusion
SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE. 相似文献20.
Christopher N. Cooley Tyler J. Beranek Matthew A. Warpinski Robert Alexander Amanda O. Esquivel 《The American journal of emergency medicine》2019,37(2):199-203