全文获取类型
收费全文 | 1840548篇 |
免费 | 135487篇 |
国内免费 | 3066篇 |
专业分类
耳鼻咽喉 | 26084篇 |
儿科学 | 62524篇 |
妇产科学 | 49242篇 |
基础医学 | 269339篇 |
口腔科学 | 50413篇 |
临床医学 | 163218篇 |
内科学 | 362086篇 |
皮肤病学 | 40968篇 |
神经病学 | 139670篇 |
特种医学 | 71579篇 |
外国民族医学 | 718篇 |
外科学 | 278953篇 |
综合类 | 39209篇 |
现状与发展 | 3篇 |
一般理论 | 515篇 |
预防医学 | 137567篇 |
眼科学 | 41529篇 |
药学 | 137959篇 |
5篇 | |
中国医学 | 4394篇 |
肿瘤学 | 103126篇 |
出版年
2018年 | 19332篇 |
2017年 | 14722篇 |
2016年 | 16255篇 |
2015年 | 18213篇 |
2014年 | 25307篇 |
2013年 | 38546篇 |
2012年 | 52211篇 |
2011年 | 55180篇 |
2010年 | 32861篇 |
2009年 | 31133篇 |
2008年 | 52308篇 |
2007年 | 56016篇 |
2006年 | 56602篇 |
2005年 | 54442篇 |
2004年 | 53192篇 |
2003年 | 51266篇 |
2002年 | 50182篇 |
2001年 | 91556篇 |
2000年 | 94419篇 |
1999年 | 79542篇 |
1998年 | 21272篇 |
1997年 | 18919篇 |
1996年 | 19473篇 |
1995年 | 18465篇 |
1994年 | 17371篇 |
1993年 | 16064篇 |
1992年 | 62417篇 |
1991年 | 61317篇 |
1990年 | 59707篇 |
1989年 | 57589篇 |
1988年 | 52837篇 |
1987年 | 51671篇 |
1986年 | 48401篇 |
1985年 | 46115篇 |
1984年 | 34360篇 |
1983年 | 28927篇 |
1982年 | 16501篇 |
1981年 | 14904篇 |
1979年 | 30762篇 |
1978年 | 21446篇 |
1977年 | 18156篇 |
1976年 | 17131篇 |
1975年 | 18613篇 |
1974年 | 21748篇 |
1973年 | 20866篇 |
1972年 | 19372篇 |
1971年 | 17777篇 |
1970年 | 16913篇 |
1969年 | 15380篇 |
1968年 | 14106篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
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
13.
María Cabrerizo Gloria Trallero María José Pena Amaia Cilla Gregoria Megias Carmen Mu?oz-Almagro Eva Del Amo Diana Roda Ana Isabel Mensalvas Antonio Moreno-Docón Juan García-Costa Nuria Rabella Manuel Ome?aca María Pilar Romero Sara Sanbonmatsu-Gámez Mercedes Pérez-Ruiz María José Santos-Mu?oz Cristina Calvo And the study group of “Enterovirus parechovirus infections in children under ?years-old Spain” PI- 《European journal of pediatrics》2015,174(11):1511-1516
14.
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15.
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
Introduction
In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.Methods
We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.Results
A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.Conclusion
The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department. 相似文献16.
Laparoscopic surgery has several advantages over traditional surgery because it has been shown to be less invasive. The next logical step in the evolution of minimally invasive surgery may be to eliminate all abdominal incisions. The natural orifices provide a port of entry via the gastrointestinal tract to the peritoneal cavity. This approach would require the creation of a perforation, which is considered to be a major complication of endoscopy with significant morbidity and mortality. However, there are several recent studies that have described the technical feasibility and safety of a per‐oral transgastric approach to the peritoneal cavity using conventional endoscopes. Theoretically, this approach could reduce postoperative abdominal wall pain, wound infection, hernia formation, and adhesions. This article aims to summarize the current status of transgastric surgery, currently referred to as natural orifice transluminal endoscopic surgery (NOTES), and to address some of its future challenges. 相似文献
17.
N. SUVAJD
I V. EMERIKI‐MARTINOVI . ARANOVI M. PETROVI M. POPOVI V. ARTIKO M. UPI I. ELEZOVI 《International journal of laboratory hematology》2006,28(5):317-320
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed. 相似文献
18.
Bernard–Soulier syndrome (BSS) is a rare autosomal recessively inherited bleeding disorder. Pregnancy in patients with BSS is characterized by ante‐, intra‐, or postpartum haemorrhage, which may be delayed and severe. There is no consensus in the management of BSS in pregnancy and so far only 16 pregnancies in nine patients have been described. We report a further three pregnancies in two women with the syndrome. We also outline our management of pregnant patients with BSS. 相似文献
19.
Lalia Y. Ibrahim Krank P. DiFilippo Geremy E. Steed Manuel D. Cerqueira 《Journal of nuclear cardiology》2006,13(6):855-866
Conclusion Several quality-control measures take place before (patient and camera preparation) and during SPECT acquisition to achieve
high-quality images. Not uncommonly, technologists and physicians are left with suboptimal images that have to be addressed
to reach the “right answer” for patient diagnosis and hence management. In many cases patients may be reimaged, especially
if the problem is detected early, but in other cases either the patient has left the nuclear laboratory or there is an inevitable
problem that, even with reimaging, will not be resolved. In these situations the technologist and physician have to seek the
available techniques to obtain the best images possible. These resources are discussed in this issue as an aid in quality
control to obtain the best possible images. 相似文献
20.