全文获取类型
收费全文 | 29118篇 |
免费 | 2351篇 |
国内免费 | 68篇 |
专业分类
耳鼻咽喉 | 575篇 |
儿科学 | 792篇 |
妇产科学 | 527篇 |
基础医学 | 3627篇 |
口腔科学 | 511篇 |
临床医学 | 3590篇 |
内科学 | 5588篇 |
皮肤病学 | 505篇 |
神经病学 | 2342篇 |
特种医学 | 1171篇 |
外科学 | 4482篇 |
综合类 | 583篇 |
一般理论 | 20篇 |
预防医学 | 2456篇 |
眼科学 | 519篇 |
药学 | 2000篇 |
中国医学 | 30篇 |
肿瘤学 | 2219篇 |
出版年
2023年 | 256篇 |
2022年 | 430篇 |
2021年 | 1065篇 |
2020年 | 610篇 |
2019年 | 950篇 |
2018年 | 1112篇 |
2017年 | 697篇 |
2016年 | 730篇 |
2015年 | 800篇 |
2014年 | 1123篇 |
2013年 | 1718篇 |
2012年 | 2092篇 |
2011年 | 2002篇 |
2010年 | 1086篇 |
2009年 | 896篇 |
2008年 | 1473篇 |
2007年 | 1544篇 |
2006年 | 1380篇 |
2005年 | 1204篇 |
2004年 | 1188篇 |
2003年 | 983篇 |
2002年 | 903篇 |
2001年 | 631篇 |
2000年 | 654篇 |
1999年 | 523篇 |
1998年 | 230篇 |
1997年 | 183篇 |
1996年 | 175篇 |
1995年 | 147篇 |
1994年 | 133篇 |
1993年 | 133篇 |
1992年 | 376篇 |
1991年 | 299篇 |
1990年 | 326篇 |
1989年 | 320篇 |
1988年 | 305篇 |
1987年 | 266篇 |
1986年 | 317篇 |
1985年 | 227篇 |
1984年 | 194篇 |
1983年 | 172篇 |
1982年 | 114篇 |
1981年 | 112篇 |
1980年 | 107篇 |
1979年 | 194篇 |
1978年 | 121篇 |
1976年 | 89篇 |
1975年 | 98篇 |
1974年 | 94篇 |
1971年 | 94篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
A. Chan R. Shinde C. C. Chow C. S. Cockram R. Swaminathan 《Clinical endocrinology》1994,41(2):213-216
OBJECTIVE Thyrotoxic periodic paralysis (TPP) usually follows a heavy carbohydrate meal and this may be explained by hyperinsulinaemia stimulating Na+, K+ -ATPase activity. To clarify this the effect of glucose load on serum insulin concentration and platelet Na+, K+ -ATPase activity In thyrotoxic periodic paralysis (TPP) was examined. DESIGN In all subjects a standard 75-g glucose tolerance test was done and blood samples were taken at 0, 1 and 2 hours. SUBJECTS Twenty-five healthy controls (8 M and 17 F), 17 uncomplicated thyrotoxic patients (7M and 10 F), 15 TPP patients who presented with paralysis and 4 TPP patients after treatment with antithyrold drugs. MEASUREMENTS Plasma glucose was measured by the glucose oxidase method, serum insulin by radioimmunoassay and platelet Na+, K+ -ATPase by the release of phosphate from ATP. RESULTS TPP patients showed glucose intolerance (area under the curve (AUC) 16·5 ± 4·4 (mean ± SD) In TPP compared to 12·9 ± 4·5 In controls (P < 0·01) and hyperinsulinaemia (AUC 189·6 ±100·6 vs 98·5 ±53·4, P < 0·001). In uncomplicated thyrotoxicosis the results were similar to that in healthy controls. Platelet Na+, K+ -ATPase were significantly higher in thyrotoxic patients compared to controls and In TPP patients were even higher. Ingestion of glucose increased platelet Na+, K+ -ATPase in all groups. AUC for platelet Na+, K+ -ATPase in TPP patients were significantly higher than in uncomplicated thyrotoxicosis (601 ±99·3 vs 482 ± 109·4, P < 0·01) or healthy controls (320 ± 107·3). In the 4 TPP patients studied after antithyroid treatment the results were similar to healthy controls. CONCLUSION Patients with thyrotoxic periodic paralysis have hyperinsulinaemia and this is accompanied by higher Na+, K+-ATPase activity. 相似文献
92.
J W Ashford V Kumar M Barringer M Becker J Bice N Ryan S Vicari 《International psychogeriatrics / IPA》1992,4(1):55-74
Diagnosis of dementia needs to be complemented by precise determination of disease severity across the broad spectrum of disease progression. The Mini-Mental State Exam (MMS), the Activities-of-Daily-Living assessment (ADL) and the Clinical Dementia Rating scale (CDR) were modified for direct comparability and administered to 112 outpatients and 45 nursing home residents with a range of dementia severity from mild to profound. The scales showed the highest correlations for the probable Alzheimer's disease patient group (62) (Global Assessment of Dementia; GAD vs. ADL: r = 0.91; Extended Mini-Mental Assessment; EMA vs. GAD: r = 0.91; ADL vs. EMA: r = 0.86). For these patients, scores on the individual scales tended to be similar. Disparity among the three scores for individual cases was associated with the presence of comorbidities. The high correlations and correspondence among these scales demonstrate their reliability, validity, and utility in the assessment of dementia severity. The use of an average of these measures, with their increased precision, may give a more accurate indication of dementia severity over a broader range of impairment. 相似文献
93.
目的 了解上海地区学生午餐营养及供应链状况,为改善学生午餐营养状况,保障食品供应安全提供参考。方法 分析上海市学生午餐的营养、卫生、供应链、加工工艺等状况,采用定期抽检的方法,应用SNHAS对营养素、食品安全、感官进行综合评价。结果 各单位样本综合评价均合格,其中热量、蛋白质、脂肪均能达到或超过DRIs供给量的要求,但矿物质中Ca(仅为AI的32%)、视黄醇当量(仅为AI的57%)供给量较低。对供应链及卫生状况的分析表明,大型企业对各个环节控制严格,产品质量较好,但也存在保存时间过长等问题。结论 应进一步完善供应体系,建立高效的质量控制体系,推广营养配膳系统。 相似文献
94.
Macrophage infiltration is frequent in the early stages of various proliferative eye disorders, including subretinal neovascularization. In this study, we set out to establish the origin of macrophages found in an animal model of laser-induced subretinal neovascularization. One primate received several intravenous injections of a colloidal carbon suspension. We then applied standard argon laser lesions to the retina of both eyes, which were enucleated eight days later and sectioned serially for histological examination. A quantitative estimate of carbon-laden and non-laden leukocytes was made based on morphological criteria. Mononuclear leukocytes accumulated in the laser lesions and the percentage of carbon-laden mononuclear leukocytes in relation to the total leukocyte number was higher in the extravascular area of the laser sites than in the systemic circulation. These findings indicate that the majority of mononuclear leukocytes that accumulate at the sites of laser lesions are derived from the systemic circulation. 相似文献
95.
Theresa Ryan Schultz RN RRT Linda Allen Napoli RRT 《Journal for specialists in pediatric nursing》2003,8(4):151-153
Collaborative Practice provides a forum for healthcare professionals to share expertise and enhance communication. 相似文献
96.
The effect of oral appliance therapy on blood pressure in patients with obstructive sleep apnea 总被引:1,自引:1,他引:0
Ryo Otsuka Fernanda Ribeiro de Almeida Alan A. Lowe Wolfgang Linden Frank Ryan 《Sleep & breathing》2006,10(1):29-36
The objective of the study was to investigate the effects of oral appliance (OA) therapy on ambulatory blood pressure in patients
with obstructive sleep apnea (OSA). Eleven OSA patients who received OA therapy were prospectively investigated. Ambulatory
blood pressure was measured for 20 h from 4:00 p.m. to 12:00 noon the next day using an ambulatory blood pressure monitor. The Respiratory Disturbance Index (RDI) was measured
in the pretreatment and posttitration periods. The OA was titrated to reach a therapeutic jaw position over 2 to 8 months,
and posttitration measurements were repeated. At posttitration, the RDI was significantly decreased from a mean (SD) of 24.7
(20.1) to 6.1 (4.5). Significant reductions in diastolic blood pressure (DBP) and mean arterial pressure (MAP) were found
for the 20-h periods, and systolic blood pressure (SBP), DBP, and MAP while asleep. The mean values were 79.5 (5.5) to 74.6
(6.0) for DBP and 95.9 (5.4) to 91.2 (5.9) for MAP, for over a 20-h period, and 118.4 (10.0) to 113.7 (9.1) for SBP, 71.6
(8.0) to 67.2 (7.9) for DBP, and 88.4 (8.0) to 83.9 (7.5) for MAP, while asleep. This study suggests that successful OSA treatment
with an OA may also be beneficial to lower blood pressure in OSA patients, as previously suggested for nasal continuous positive
airway pressure therapy.
This study was conducted in the Division of Orthodontics, The University of British Columbia, Canada 相似文献
97.
What is the prognostic value of myocardial perfusion imaging using rubidium-82 positron emission tomography? 总被引:5,自引:0,他引:5
Keiichiro Yoshinaga Benjamin J W Chow Kathryn Williams Li Chen Robert A deKemp Linda Garrard Alexander Lok-Tin Szeto May Aung Ross A Davies Terrence D Ruddy Rob S B Beanlands 《Journal of the American College of Cardiology》2006,48(5):1029-1039
OBJECTIVES: The objective was to determine the prognostic value of rubidium-82 (82Rb) positron emission tomography (PET) myocardial perfusion imaging (MPI). BACKGROUND: 82Rb PET MPI accurately diagnoses coronary artery disease (CAD). However, there are limited data evaluating its prognostic value. METHODS: Follow-up (3.1 +/- 0.9 years) was obtained in 367 patients who underwent dipyridamole 82Rb PET MPI. Patients were divided into groups based on their summed stress score (SSS): group I, normal (<4); group II, mild (4 to 7); and group III, moderate (8 to 11) to severe (> or =12). RESULTS: There were significant differences among patients in the 3 SSS groups for hard events (cardiac death and myocardial infarction [MI]) (p < 0.001) and total cardiac events (hard events, revascularization and hospitalization) (p < 0.001). The annual hard events rates were 0.4%, 2.3%, and 7.0% in the normal, mild, and moderate-severe groups, respectively. In adjusted survival models, 82Rb PET SSS was the strongest predictor of total cardiac events and a significant predictor of hard events. Among patients referred for PET after 99mTc single-photon emission computed tomography, the annual total event rate was higher with abnormal versus normal SSS on PET (15.2% vs. 1.3%, p < 0.001). In patients with obesity, the annual total event rate was 11.1% with an abnormal scan and 1.5% with a normal scan (p < 0.001). CONCLUSIONS: This study shows that 82Rb PET MPI has significant prognostic value for predicting cardiac events, including death and MI. It also seems to have prognostic value in patients whose diagnosis remains uncertain after single-photon emission computed tomography MPI and in obese patients. The prognostic value of PET MPI may improve the management of cardiac patients. 相似文献
98.
Ryan M McAdams Edward Mazuchowski Michael W Ellis Michael Rajnik 《Journal of perinatology》2005,25(10):677-679
Hospitalized neonates are commonly colonized soon after birth with Staphylococcus aureus. The majority of neonates do not develop infectious sequelae; however, premature neonates appear to be more susceptible to serious infections, such as pneumonia. We report a case of an extremely low birth weight infant who developed necrotizing pneumonia due to methicillin-resistant Staphylococcal aureus (MRSA). The MRSA isolate from this neonate is identical to the strains that have been causing primarily community-associated skin and soft tissue infections. The severe course of this patient may be attributed to the presence of the Panton-Valentine leukocidin gene, a well-known virulence factor leading to soft tissue and pulmonary infections. 相似文献
99.
L C Chen I Berberian B Koch M Mercier V Azais-Braesco H P Glauert C K Chow L W Robertson 《Toxicology and applied pharmacology》1992,114(1):47-55
The purpose of this study was to examine the structural requirements of polychlorinated and polybrominated biphenyls (PCBs and PBBs) for altering tissue levels of retinoids. Seven congeneric PCBs and PBBs were studied: 3,3',4,4'-tetrachlorobiphenyl (TCB), 2',3,3',4,5- and 3,3',4,4',5-pentachlorobiphenyls (-PeCBs), 3,3',4,4'- and 3,3',5,5'-tetrabromobiphenyls (-TBBs), 2,2',3,3',5,5'-hexachlorobiphenyl (-HCB), and 3,3',4,4',5,5'-hexabromobiphenyl (-HBB). Male Sprague-Dawley rats were fed a vitamin A-adequate diet (1.3 mg/kg) for 30 days before being given a single IP injection of one of seven polyhalogenated biphenyls (150 mumol/kg) in corn oil (10 ml/kg) or vehicle alone. Rats were killed 1 week later. Except for 3,3',4,4',5,5'-HBB, all PCBs and PBBs studied significantly decreased serum retinol levels and, except for 3,3',4,4',5,5'-HBB and 2,2',3,3',5,5'-HCB, all PCBs and PBBs also lowered the serum retinol-binding-protein (RBP) content. The activity of hepatic retinyl ester hydrolase (REH) was reduced by the treatment of 3,3',4,4',5-PeCB, 3,3',4,4'-TBB, and 3,3',4,4',5,5'-HBB. The levels of hepatic retinol were decreased by 2,2',3,3',5,5'-HCB, 2',3,3',4,5-PeCB, and 3,3',4,4',5-PeCB, while levels of hepatic retinyl palmitate were decreased by 2',3,3',4,5-PeCB, 3,3',4,4',5-PeCB, 3,3',4,4'-TCB, 3,3',4,4'-TBB, and 3,3',4,4',5,5'-HBB. The substantial decreases in hepatic retinyl palmitate levels could not be explained solely on the basis of hepatomegaly caused by acutely toxic PCBs and PBBs. All halogenated biphenyls which caused a decrease in hepatic retinyl palmitate also caused an increase in renal retinyl palmitate except 3,3',4,4',5-PeCB. In summary, the acutely toxic (nonortho substituted) congeners had pronounced effects on hepatic, renal, and serum retinoids whereas other biphenyls only decreased serum retinol levels. The effects of these seven compounds on REH activity were not correlated with the effects on serum retinol or RBP levels. Therefore, this study shows that the structure-activity relationships for altering hepatic retinoids differ from those for serum retinol, implying the involvement of multiple mechanisms. 相似文献
100.