全文获取类型
收费全文 | 4899篇 |
免费 | 313篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 120篇 |
妇产科学 | 113篇 |
基础医学 | 716篇 |
口腔科学 | 87篇 |
临床医学 | 664篇 |
内科学 | 1041篇 |
皮肤病学 | 91篇 |
神经病学 | 604篇 |
特种医学 | 141篇 |
外科学 | 458篇 |
综合类 | 31篇 |
一般理论 | 4篇 |
预防医学 | 359篇 |
眼科学 | 92篇 |
药学 | 262篇 |
中国医学 | 7篇 |
肿瘤学 | 393篇 |
出版年
2024年 | 7篇 |
2023年 | 39篇 |
2022年 | 65篇 |
2021年 | 156篇 |
2020年 | 91篇 |
2019年 | 132篇 |
2018年 | 149篇 |
2017年 | 114篇 |
2016年 | 153篇 |
2015年 | 176篇 |
2014年 | 213篇 |
2013年 | 243篇 |
2012年 | 377篇 |
2011年 | 378篇 |
2010年 | 257篇 |
2009年 | 206篇 |
2008年 | 319篇 |
2007年 | 351篇 |
2006年 | 283篇 |
2005年 | 272篇 |
2004年 | 267篇 |
2003年 | 223篇 |
2002年 | 251篇 |
2001年 | 46篇 |
2000年 | 54篇 |
1999年 | 53篇 |
1998年 | 44篇 |
1997年 | 41篇 |
1996年 | 32篇 |
1995年 | 32篇 |
1994年 | 30篇 |
1993年 | 16篇 |
1992年 | 20篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 16篇 |
1988年 | 18篇 |
1987年 | 15篇 |
1986年 | 15篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1972年 | 4篇 |
1969年 | 3篇 |
1966年 | 3篇 |
1965年 | 4篇 |
排序方式: 共有5248条查询结果,搜索用时 15 毫秒
31.
Astrid A. Hoberg Kristin S. VickersJoanne Ericksen Grant BauerSimon Kung Randy StoneMark Williams Mary Jo MooreMark A. Frye 《Archives of Psychiatric Nursing》2013
The effectiveness of psychotherapies, such as interpersonal and social rhythm therapy (IPSRT), is supported by randomized controlled trials. These trials provide minimal direction regarding feasibility of psychotherapy delivery models. The study purpose was to identify factors facilitating implementation and sustainability of an IPRST group for patients with bipolar disorder. Qualitative data were assessed by the normalization process model (NPM). The results demonstrate feasibility of implementation with experienced clinicians, program coordination, and leadership support. Sustainability challenges include aftercare groups, space, and clinician time. The NPM provides a useful framework for evaluation of factors influencing the feasibility of psychotherapy delivery models. 相似文献
32.
Verberne HJ Sokole EB van Moerkerken AF Deeterink JH Ensing G Stabin MG Somsen GA van Eck-Smit BL 《European journal of nuclear medicine and molecular imaging》2008,35(4):798-807
Purpose We hypothesized that assessment of myocardial sympathetic activity with no-carrier-added (nca) 123I-meta-iodobenzylguanidine (MIBG) compared to carrier-added (ca) 123I-MIBG would lead to an improvement of clinical performance without major differences in radiation dosimetry.
Methods In nine healthy volunteers, 15 min and 4 h planar thoracic scintigrams and conjugate whole-body scans were performed up to
48 h following intravenous injection of 185 MBq 123I-MIBG. The subjects were given both nca and ca 123I-MIBG. Early heart/mediastinal ratios (H/M), late H/M ratios and myocardial washout were calculated. The fraction of administered
activity in ten source organs was quantified from the attenuation-corrected geometric mean counts in conjugate views. Radiation-absorbed
doses were estimated with OLINDA/EXM software.
Results Both early and late H/M were higher for nca 123I-MIBG (ca 123I-MIBG early H/M 2.46 ± 0.15 vs nca 123I-MIBG 2.84 ± 0.15, p = 0.001 and ca 123I-MIBG late H/M 2.69 ± 0.14 vs nca 123I-MIBG 3.34 ± 0.18, p = 0.002). Myocardial washout showed a longer retention time for nca 123I-MIBG (p < 0.001). The effective dose equivalent (adult male model) for nca 123I-MIBG was similar to that for ca 123I-MIBG (0.025 ± 0.002 mSv/MBq vs 0.026 ± 0.002 mSv/MBq, p = 0.055, respectively).
Conclusion No-carrier-added 123I-MIBG yields a higher relative myocardial uptake and is associated with a higher myocardial retention. This difference between
nca 123I-MIBG and ca 123I-MIBG in myocardial uptake did not result in major differences in estimated absorbed doses. Therefore, nca 123I-MIBG is to be preferred over ca 123I-MIBG for the assessment of cardiac sympathetic activity. 相似文献
33.
Schimmelmann BG Friedel S Christiansen H Dempfle A Hinney A Hebebrand J 《Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie》2006,34(6):425-433
Attention-Deficit and Hyperactivity Disorder (ADHD) is a common child and adolescent psychiatric disorder with a prevalence rate of 3-7%. Formal genetic studies provided an estimated heritability of 0.6-0.8 and an approximately five-fold elevated risk for ADHD in first-degree relatives. Currently, four genome scans have led to the identification of chromosomal regions potentially relevant in ADHD; especially the evidence for linkage to chromosome 5p13 is convincing. Meta-analyses of a large number of candidate gene studies suggest association with gene variants of the dopaminergic receptors DRD4 and DRD5, the serotonergic receptor HTR1B, and the synaptosomal receptor protein (SNAP-25). Hyperactivity has been investigated particularly in animal models, focusing on knockout- and quantitative trait loci (QTL) designs, with promising results for the dopaminergic system. It is likely that several gene polymorphisms with moderate to small effect sizes contribute to the phenotype ADHD; different combinations of such predisposing variants presumably underlie ADHD in different individuals. Therefore, large samples for molecular genetic studies are mandatory to detect these polymorphisms. Accordingly, several of today's findings have to be regarded as preliminary. The understanding of ADHD's neurobiology may be advanced by new technologies, such as SNP-based genome scans performed with gene chips comprising 10,000-1,000,000 SNPs, as well as using more sophisticated animal model designs. 相似文献
34.
Fink AM Lass H Hartleb H Jurecka W Salzer H Steiner A 《Annals of surgical oncology》2008,15(3):848-853
Background One-half of breast cancer patients with positive sentinel lymph node (SN) have no further metastases in the axillary lymph
node basin. The aim of the present study was to identify patients with positive SN who are unlikely to have further metastases
in the axillary lymph node basin, using a new classification of SN, namely the S-classification.
Methods Specimens of positive SN were subjected to a pathological review according to the previously published S-classification. S-stages
of positive SN were correlated with the status of further metastases in the axillary lymph node basin after axillary lymph
node dissection (ALND).
Results Of 117 patients who underwent sentinel lymph node biopsy, 36 (30.8%) had a positive SN and were subjected to level I and II
ALND. The occurrence of positive nonsentinel nodes was significantly related to the S-stage of SN. No patient with stage SI
had additional metastases in the nonsentinel lymph nodes, while 14.3% of patients with SII stage disease and 60.9 % of patients
with SIII disease had other non-SN that were metastatic.
Conclusion S-stages of positive SN are highly predictive for axillary nonsentinel node status. Especially patients with SI sentinel node
metastases appear to be at low risk for further nonsentinel node metastases. 相似文献
35.
36.
37.
38.
Christian Medom Madsen Henrik Løvendahl Jørgensen Astrid Norgaard Troels Riis Christopher Jantzen Ole Birger Pedersen Benn Rønnow Duus Jes Bruun Lauritzen 《Archives of orthopaedic and trauma surgery》2014,134(3):375-382
Introduction
Red blood cell (RBC) transfusion is a frequently used treatment in patients admitted with a fractured hip, but the use remains an area of much debate. The aim of this study was to determine preoperative factors associated with the risk of receiving a red blood cell transfusion in hip fracture patients.Method
The study included 986 consecutive hip fracture patients (aged 60 years or above). The patients were identified from a database of all hip fracture patients admitted to Bispebjerg University Hospital. Data for the database are collected via chart review and data extraction from the hospitals laboratory system, public registries and from the Capital Region Blood Bank Database.Results
Overall transfusion rate was 58.7 %. The univariate analyses showed that transfusion rate was higher among women (p = 0.004), older patients (p < 0.0001), patients with high ASA scores (p < 0.0001), patients with more severe fractures (p < 0.0001), patients with lower admission haemoglobin levels (p < 0.0001), patients not admitted from own home (p = 0.02) and patients taking aspirin (p = 0.007) or other platelet inhibitors (p = 0.01) on admission. In the multivariate analysis, increasing age, ASA ≥3, being admitted from own home, extracapsular fractures, decreasing admission haemoglobin and use of platelet inhibitors were all significantly associated with the risk of receiving a RBC transfusion.Conclusion
Several readily available preoperative factors in the form of age, residence, ASA, admission haemoglobin, medication and type of fracture were independently associated with the likelihood of receiving a red blood cell transfusion in patients admitted with a fractured hip. 相似文献39.
Genetic predisposition for adult lactose intolerance and relation to diet, bone density, and bone fractures. 总被引:8,自引:0,他引:8
Barbara M Obermayer-Pietsch Christine M Bonelli Daniela E Walter Regina J Kuhn Astrid Fahrleitner-Pammer Andrea Berghold Walter Goessler Vinzenz Stepan Harald Dobnig Georg Leb Wilfried Renner 《Journal of bone and mineral research》2004,19(1):42-47
Evidence that genetic disposition for adult lactose intolerance significantly affects calcium intake, bone density, and fractures in postmenopausal women is presented. PCR-based genotyping of lactase gene polymorphisms may complement diagnostic procedures to identify persons at risk for both lactose malabsorption and osteoporosis. INTRODUCTION: Lactase deficiency is a common autosomal recessive condition resulting in decreased intestinal lactose degradation. A -13910 T/C dimorphism (LCT) near the lactase phlorizin hydrolase gene, reported to be strongly associated with adult lactase nonpersistence, may have an impact on calcium supply, bone density, and osteoporotic fractures in the elderly. MATERIALS AND METHODS: We determined LCT genotypes TT, TC, and CC in 258 postmenopausal women using a polymerase chain reaction-based assay. Genotypes were related to milk intolerance, nutritional calcium intake, intestinal calcium absorption, bone mineral density (BMD), and nonvertebral fractures. RESULTS: Twenty-four percent of all women were found to have CC genotypes and genetic lactase deficiency. Age-adjusted BMD at the hip in CC genotypes and at the spine in CC and TC genotypes was reduced by -7% to -11% depending on the site measured (p = 0.04). LCT(T/C-13910) polymorphisms alone accounted for 2-4% of BMD in a multiple regression model. Bone fracture incidence was significantly associated with CC genotypes (p = 0.001). Milk calcium intake was significantly lower (-55%, p = 0.004) and aversion to milk consumption was significantly higher (+166%, p = 0.01) in women with the CC genotype, but there were no differences in overall dietary calcium intake or in intestinal calcium absorption test values. CONCLUSION: The LCT(T/C-13910) polymorphism is associated with subjective milk intolerance, reduced milk calcium intake, and reduced BMD at the hip and the lumbar spine and may predispose to bone fractures. Genetic testing for lactase deficiency may complement indirect methods in the detection of individuals at risk for both lactose malabsorption and osteoporosis. 相似文献
40.
Increased response of renal perfusion to the antioxidant vitamin C in type 2 diabetes. 总被引:2,自引:0,他引:2
Christian Delles Markus P Schneider Sebastian Oehmer Ingrid Fleischmann Erwin F Fleischmann Roland E Schmieder 《Nephrology, dialysis, transplantation》2004,19(10):2513-2518
BACKGROUND: Reactive oxygen species play a major role in the development of endothelial dysfunction. It is as yet unspecified whether increased oxidative stress contributes to endothelial dysfunction of the renal vasculature in patients with type 2 diabetes. METHODS: Renal haemodynamics were studied in 20 patients with type 2 diabetes and arterial hypertension (age 62 +/- 5 years) and 20 non-diabetic hypertensive patients at baseline and following infusions of the nitric oxide synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA; 4.25 mg/kg); the substrate of nitric oxide synthase, L-arginine (100 mg/kg); and the antioxidant, vitamin C (3 g, co-infused with L-arginine 100 mg/kg). RESULTS: The response of renal plasma flow (RPF) to L-NMMA (-54 +/- 62 and -45 +/- 42 ml/min/1.73 m(2); P = NS) and L-arginine (+46 +/- 36 and +49 +/- 25 ml/min/1.73 m(2); P = NS) was not different between diabetic and non-diabetic patients. In contrast, vitamin C induced a more pronounced increase in RPF in diabetic than in non-diabetic patients when co-infused with L-arginine (+71+/-47 and +43+/-33 ml/min/1.73 m(2); P<0.05). CONCLUSIONS: The difference in the response of renal perfusion to an antioxidant suggests increased formation of reactive oxygen species and thereby reduced nitric oxide bioavailability in the renal vasculature of patients with type 2 diabetes. 相似文献