全文获取类型
收费全文 | 6537篇 |
免费 | 674篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 190篇 |
妇产科学 | 177篇 |
基础医学 | 871篇 |
口腔科学 | 226篇 |
临床医学 | 793篇 |
内科学 | 1097篇 |
皮肤病学 | 135篇 |
神经病学 | 454篇 |
特种医学 | 397篇 |
外科学 | 849篇 |
综合类 | 242篇 |
一般理论 | 4篇 |
预防医学 | 622篇 |
眼科学 | 68篇 |
药学 | 579篇 |
中国医学 | 32篇 |
肿瘤学 | 430篇 |
出版年
2021年 | 92篇 |
2020年 | 50篇 |
2019年 | 109篇 |
2018年 | 128篇 |
2017年 | 87篇 |
2016年 | 107篇 |
2015年 | 110篇 |
2014年 | 152篇 |
2013年 | 226篇 |
2012年 | 261篇 |
2011年 | 331篇 |
2010年 | 195篇 |
2009年 | 169篇 |
2008年 | 250篇 |
2007年 | 279篇 |
2006年 | 241篇 |
2005年 | 230篇 |
2004年 | 233篇 |
2003年 | 219篇 |
2002年 | 201篇 |
2001年 | 194篇 |
2000年 | 189篇 |
1999年 | 160篇 |
1998年 | 118篇 |
1997年 | 89篇 |
1996年 | 95篇 |
1995年 | 86篇 |
1994年 | 73篇 |
1993年 | 83篇 |
1992年 | 123篇 |
1991年 | 138篇 |
1990年 | 139篇 |
1989年 | 155篇 |
1988年 | 147篇 |
1987年 | 155篇 |
1986年 | 135篇 |
1985年 | 132篇 |
1984年 | 108篇 |
1983年 | 99篇 |
1982年 | 79篇 |
1981年 | 50篇 |
1980年 | 55篇 |
1979年 | 76篇 |
1978年 | 65篇 |
1975年 | 50篇 |
1974年 | 66篇 |
1973年 | 71篇 |
1972年 | 52篇 |
1971年 | 52篇 |
1969年 | 50篇 |
排序方式: 共有7255条查询结果,搜索用时 31 毫秒
1.
Carlo De-Carolis Geraldine-A. Boyd Luca Mancinelli Stefano Pagano Stefano Eramo 《Medicina oral, patología oral y cirugía bucal》2015,20(2):e205-e210
With easy chemical synthesis from its precursor, methamphetamine (MA) is now widespread in many countries. The abuse of methamphetamine is associated with several negative effects on health, because MA is a neurotoxin and a dangerous central nervous system stimulant. It changes levels of neurotransmitters in the brain, releasing dopamine and inhibiting nor epinephrine uptake which increases sympathetic nervous system activity and can lead to cardiac arrhythmia, hypertension and tachypnea. The consequences of MA abuse are clearly manifested in oral diseases (like “meth mouth”) which is characterised by extensive caries, teeth grinding with ensuing dental wear and trismus. The present review was designed to fill the gap in knowledge about methamphetamine abuse in the European Union (EU) and to illustrate the main clinical effects of prolonged use. After describing the pharmacology and systemic effects of methamphetamine and concentrating on its effects on the mouth, the present review compares the epidemiology and incidence of abuse in the world, particularly the USA and the EU.
Key words:Methamphetamine, “Meth mouth”, drug abuse, oral health. 相似文献
2.
Danielle E Whittier Elizabeth J Samelson Marian T Hannan Lauren A Burt David A Hanley Emmanuel Biver Pawel Szulc Elisabeth Sornay-Rendu Blandine Merle Roland Chapurlat Eric Lespessailles Andy Kin On Wong David Goltzman Sundeep Khosla Serge Ferrari Mary L Bouxsein Douglas P Kiel Steven K Boyd 《Journal of bone and mineral research》2022,37(3):428-439
Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a “one-size-fits-all” approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured. In this study, we propose that there are common combinations of bone properties, referred to as phenotypes, that are predisposed to different levels of fracture risk. Using HR-pQCT data from a multinational cohort (n = 5873, 71% female) between 40 and 96 years of age, we employed fuzzy c-means clustering, an unsupervised machine-learning method, to identify phenotypes of bone microarchitecture. Three clusters were identified, and using partial correlation analysis of HR-pQCT parameters, we characterized the clusters as low density, low volume, and healthy bone phenotypes. Most males were associated with the healthy bone phenotype, whereas females were more often associated with the low volume or low density bone phenotypes. Each phenotype had a significantly different cumulative hazard of major osteoporotic fracture (MOF) and of any incident osteoporotic fracture (p < 0.05). After adjustment for covariates (cohort, sex, and age), the low density followed by the low volume phenotype had the highest association with MOF (hazard ratio = 2.96 and 2.35, respectively), and significant associations were maintained when additionally adjusted for femoral neck aBMD (hazard ratio = 1.69 and 1.90, respectively). Further, within each phenotype, different imaging biomarkers of fracture were identified. These findings suggest that osteoporotic fracture risk is associated with bone phenotypes that capture key features of bone deterioration that are not distinguishable by aBMD. © 2021 American Society for Bone and Mineral Research (ASBMR). 相似文献
3.
4.
5.
6.
Summary This study explores the effects of a calcium-deficient diet on patterns of bone remodeling, and examines regional differences
in the amount of bone lost. Skeletally mature female rabbits (n=6) were fed a calcium-deficient diet (0.10% Ca2+ and 0.50% P) for 14 weeks. A separate group of rabbits (n=4) were fed a maintenance diet (1.2% Ca2+ and 0.45% P). Bone mineral content, serum calcium, and serum phosphorus were measured each week during the experimental period.
Following sacrifice, the L3 vetebra, femoral head, proximal tibial metaphysis, and tibial midshaft were analyzed histomorphometrically. Rabbits had 20%
less vertebral bone after only 14 weeks of a calcium-deficient diet. As in human postmenopausal osteoporosis, bone loss in
calcium-deficient rabbits occurs in the trabecular bone of the lumbar spine before that in the trabecular bone of the lower
extremity. Calcium-deficient diets alone do not lead to increased osteoid volume or thickness. Because bone loss is relatively
rapid and because the pattern of loss is similar in some respects to that found in humans, adult rabbits may provide an attractive
model of calcium deficiency osteoporosis in a skeletally mature mammal in which remodeling is predominant over modeling. 相似文献
7.
OBJECTIVE: To assess the frequency of risk factors for rhabdomyolysis with simvastatin and atorvastatin in cases reported to the Australian Adverse Drug Reactions Advisory Committee (ADRAC). DESIGN: Reports meeting the definition of rhabdomyolysis were reviewed for risk factors including age > or = 70 years, dose > or = 40 mg, hepatic dysfunction, diabetes mellitus, hyperkalaemia, hypothyroidism and the use of concomitant interacting medications. RESULTS: Only one report associated with simvastatin and five reports associated with atorvastatin did not list any risk factors for rhabdomyolysis. Interacting medicines featured in 77% of reports of rhabdomyolysis associated with simvastatin and 44% of reports associated with atorvastatin. A comparison of the age profile for reports of atorvastatin- and simvastatin-associated rhabdomyolysis with that for all adverse drug reaction reports received, and for all reports of muscle disorders, suggested a trend towards an increasing risk of rhabdomyolysis with increasing age with simvastatin but not with atorvastatin. Similarly, comparing prescribed tablet strengths from Pharmaceutical Benefits Scheme data with the HMG-CoA reductase inhibitor ('statin') doses in reports of rhabdomyolysis suggested a dose-related risk with simvastatin, but a less increased risk with high-dose atorvastatin. CONCLUSION: Risk factors for rhabdomyolysis featured in nearly all of the reports of statin-associated rhabdomyolysis and the majority of reports listed multiple risk factors, although dependence on risk factors appeared to be stronger with simvastatin than atorvastatin. The multiplication of risk factors in patients taking simvastatin and atorvastatin should be minimised. 相似文献
8.
For patients taking two or more medications concurrently, interactions among the drugs can cause undesirable effects or negate desired responses. In modern pharmacy practice, an important role of the pharmacist is to detect potentially harmful interactions and take appropriate action to prevent their occurrence. Pharmacy computer systems offer potential for improving pharmacists' effectiveness in the detection and followup of drug interactions. Based on a survey of southern Michigan pharmacists, relationships between computer use and pharmacists' attitudes and activities in drug interaction monitoring were investigated. Respondents included users of two major computer systems as well as pharmacists who do not use computers. Results suggest that general statements cannot be made about the effect of computer use on drug interaction detection. Users of one of the two computer systems detected and followed up on interactions more frequently and were more likely to report improved knowledge of drug interactions than non-users. Frequencies of drug interaction detection and other related measures reported by users of the second computer system were similar to those for pharmacists not using computers. Computer system characteristics which might lead to these differences are discussed. 相似文献
9.
10.
Greg A Kossena William N Charman Ben J Boyd Christopher J H Porter 《Journal of controlled release》2004,99(2):217-229
The existence of a novel cubic liquid crystalline phase is described within the pseudo-ternary system comprising lauric acid, monolaurin, and simulated endogenous intestinal fluid (SEIF). This phase behaviour has been characterized using cross-polarizing light microscopy (CPLM), and the structure of the cubic phase identified by small angle X-ray scattering (SAXS). The presence of the cubic phase was found to be temperature sensitive within the 20-37 degrees C range making it putative material for in situ gelation purposes. The cubic phase was shown to have a high capacity to solubilise a model poorly water-soluble drug, cinnarizine, and initial in vitro release data highlight the potential of this phase to provide sustained release. Absorption of cinnarizine from the cubic phase was studied in an unconscious rat model via duodenal administration and blood sampling via the carotid artery. The rate of absorption was significantly reduced when compared to a simple suspension formulation, a likely combination of retarded erosion of the cubic phase together with hindered drug release from the cubic matrix. The results of this study suggest that this cubic phase may potentially be of benefit in the delivery of poorly water-soluble compounds due to its high loading capacity and potential for sustained release. The ability to manipulate this system using temperature may warrant further interest in delivery applications via other routes of administration. 相似文献