全文获取类型
收费全文 | 11326篇 |
免费 | 748篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 55篇 |
儿科学 | 296篇 |
妇产科学 | 149篇 |
基础医学 | 1418篇 |
口腔科学 | 421篇 |
临床医学 | 1300篇 |
内科学 | 2505篇 |
皮肤病学 | 93篇 |
神经病学 | 986篇 |
特种医学 | 343篇 |
外国民族医学 | 3篇 |
外科学 | 1167篇 |
综合类 | 561篇 |
一般理论 | 16篇 |
预防医学 | 1196篇 |
眼科学 | 195篇 |
药学 | 875篇 |
中国医学 | 11篇 |
肿瘤学 | 503篇 |
出版年
2023年 | 64篇 |
2022年 | 94篇 |
2021年 | 238篇 |
2020年 | 149篇 |
2019年 | 198篇 |
2018年 | 268篇 |
2017年 | 174篇 |
2016年 | 218篇 |
2015年 | 242篇 |
2014年 | 316篇 |
2013年 | 464篇 |
2012年 | 757篇 |
2011年 | 885篇 |
2010年 | 468篇 |
2009年 | 420篇 |
2008年 | 726篇 |
2007年 | 850篇 |
2006年 | 770篇 |
2005年 | 777篇 |
2004年 | 738篇 |
2003年 | 728篇 |
2002年 | 619篇 |
2001年 | 167篇 |
2000年 | 137篇 |
1999年 | 131篇 |
1998年 | 126篇 |
1997年 | 86篇 |
1996年 | 68篇 |
1995年 | 73篇 |
1994年 | 67篇 |
1993年 | 60篇 |
1992年 | 61篇 |
1991年 | 83篇 |
1990年 | 93篇 |
1989年 | 64篇 |
1988年 | 45篇 |
1987年 | 46篇 |
1986年 | 68篇 |
1985年 | 46篇 |
1984年 | 54篇 |
1983年 | 47篇 |
1982年 | 25篇 |
1980年 | 22篇 |
1979年 | 34篇 |
1978年 | 24篇 |
1975年 | 21篇 |
1974年 | 23篇 |
1973年 | 21篇 |
1971年 | 23篇 |
1966年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461
Background
The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.Methods
A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.Results
Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.Conclusions
In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler. 相似文献2.
3.
Critical care nurses within acute care settings are responsible for providing healthcare to a wide variety of patients and, consequently, knowledge regarding how to care for a patient with acute necrotizing fasciitis is imperative. A case study is presented to evidence the need for a multidisciplinary approach. Necrotizing fasciitis is defined and treatment options are presented. Caring for this patient is very challenging and demands a multidisciplinary team to coordinate all aspects of care to promote better patient outcomes. 相似文献
4.
Charles Opondo Stephen Ntoburi John Wagai Jackline Wafula Aggrey Wasunna Fred Were Annah Wamae Santau Migiro Grace Irimu Mike English 《Tropical medicine & international health : TM & IH》2009,14(10):1165-1172
Objective To assess the availability of resources that support the provision of basic neonatal care in eight first‐referral level (district) hospitals in Kenya. Methods We selected two hospitals each from four of Kenya’s eight provinces with the aim of representing the diversity of this part of the health system in Kenya. We created a checklist of 53 indicator items necessary for providing essential basic care to newborns and assessed their availability at each of the eight hospitals by direct observation, and then compared our observations with the opinions of health workers providing care to newborns on recent availability for some items, using a self‐administered structured questionnaire. Results The hospitals surveyed were often unable to maintain a safe hygienic environment for patients and health care workers; staffing was insufficient and sometimes poorly organised to support the provision of care; some key equipment, laboratory tests, drugs and consumables were not available while patient management guidelines were missing in all sites. Conclusion Hospitals appear relatively poorly prepared to fill their proposed role in ensuring newborn survival. More effective interventions are needed to improve them to meet the special needs of this at‐risk group. 相似文献
5.
Pesticide-related health problems and farmworkers 总被引:1,自引:0,他引:1
M Moses 《AAOHN journal》1989,37(3):115-130
1. Migrant and seasonal farmworkers are primarily ethnic minorities who are excluded from federal laws that protect other workers. Farmworkers live and work under substandard conditions that place them at increased risk of pesticide-related illness. 2. Agriculture uses 80% of all pesticides in the U.S. Handlers who mix, load and apply pesticides as well as workers cultivating and harvesting crops sprayed with them are at risk of acute poisoning or even death from their exposures. Drift and run-off of agricultural pesticides pollute the air, soil and water, creating additional hazards to workers' families, community residents, and the environment. 3. Chronic effects, including cancer in adults and children, adverse reproductive outcomes, delayed neuropathy and neurobehavioral effects, are also associated with occupational and environmental exposure to pesticides. 相似文献
6.
Popliteal artery aneurysms representing 80% of peripheral artery aneurysms rarely rupture (a reported incidence of 0.1–2.8
%) and second commonest in frequency after aorto-iliac aneurysms. They usually present with pain, swelling, occlusion or distal
embolisation and can cause diagnostic difficulties. We report a 78 year old man who was previously admitted to hospital with
a pulmonary embolus secondary to deep venous thrombosis. He was heparinized then warfarinised and was readmitted with a ruptured
popliteal aneurysm leading to a large pseudo aneurysm formation. The pulmonary embolus had been due to popliteal vein thrombosis
and propagation of the clot. A thorough review of literature identified only one previously reported case of ruptured popliteal
artery aneurysm and subsequent large pseudo aneurysm formation. We feel it is important to exclude a popliteal aneurysm in
a patient with DVT. This may be more common than the published literature suggests. 相似文献
7.
8.
Evagelos N Liberopoulos Eleni Papavasiliou George A Miltiadous Marios Cariolou Kostas C Siamopoulos Alexandros D Tselepis Moses S Elisaf 《Peritoneal dialysis international》2004,24(6):580-589
OBJECTIVE: The more atherogenic lipid profile seen in peritoneal dialysis (PD) patients cannot fully explain the increased incidence of atherosclerosis in this population. Oxidative modification of low-density lipoproteins (LDL) is considered to play a central role in the atherogenic process, whereas high-density lipoprotein (HDL) protects LDL from oxidation. On the other hand, it has been suggested that the LDL and HDL of PD patients are more resistant to oxidation than those of control subjects, while PD-HDL equally protects LDL from oxidation compared to control-HDL. Two HDL-associated enzymes have been shown to protect both LDL and HDL from oxidation: paraoxonase (PON1) and HDL-associated platelet-activating factor acetylhydrolase (HDL-PAF-AH). Furthermore, low PON1 activity and high total plasma PAF-AH concentration, which represents mainly the LDL-associated enzyme, have been shown to be independent risk factors for coronary artery events in the general population. However, there are limited data regarding possible alterations of these enzymes in PD patients. The aim of our study was to examine the possible alterations of PON1 and PAF-AH activities in patients undergoing PD. DESIGN: A cross-sectional study. SETTING: A university medical center. PARTICIPANTS: 56 PD patients of Caucasian origin and 86 matched controls were studied. MEASUREMENTS: In all subjects, serum PON1 activity toward paraoxon (paraoxonase) and phenylacetate (arylesterase), as well as total serum and HDL-PAF-AH activities were measured; PON1 genetic polymorphisms known to influence PON1 activity (Q192R and M55L) were determined. RESULTS: The PD patients exhibited significantly increased serum PON1 (paraoxonase) and PON1 (arylesterase) activities compared to controls, regardless of the PON1 polymorphisms or the levels of HDL cholesterol. Additionally, PD patients had significantly elevated activities of total serum PAF-AH and HDL-PAF-AH, independently of the levels of LDL or HDL cholesterol. The ratio of HDL-PAF-AH/ total PAF-AH, which has recently been suggested to be a potential marker of atherogenicity, was decreased in these patients compared to controls. Moreover, no difference in the prevalence of PON1 polymorphisms between PD patients and controls was found. CONCLUSION: The elevated activities of PON1 and HDL-PAF-AH could explain the increased resistance of PD-HDL to oxidation; the higher activity of total PAF-AH and the decreased HDL-PAF-AH/ total PAF-AH ratio could contribute to the increased incidence of atherosclerosis in these patients. 相似文献
9.
10.