全文获取类型
收费全文 | 1207篇 |
免费 | 88篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 23篇 |
妇产科学 | 46篇 |
基础医学 | 228篇 |
口腔科学 | 17篇 |
临床医学 | 183篇 |
内科学 | 230篇 |
皮肤病学 | 10篇 |
神经病学 | 96篇 |
特种医学 | 25篇 |
外科学 | 99篇 |
综合类 | 9篇 |
预防医学 | 118篇 |
眼科学 | 7篇 |
药学 | 120篇 |
中国医学 | 1篇 |
肿瘤学 | 73篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 7篇 |
2021年 | 25篇 |
2020年 | 18篇 |
2019年 | 26篇 |
2018年 | 29篇 |
2017年 | 30篇 |
2016年 | 29篇 |
2015年 | 24篇 |
2014年 | 64篇 |
2013年 | 67篇 |
2012年 | 82篇 |
2011年 | 100篇 |
2010年 | 53篇 |
2009年 | 40篇 |
2008年 | 76篇 |
2007年 | 86篇 |
2006年 | 79篇 |
2005年 | 74篇 |
2004年 | 56篇 |
2003年 | 55篇 |
2002年 | 61篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 19篇 |
1997年 | 15篇 |
1996年 | 18篇 |
1995年 | 5篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 12篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 12篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 6篇 |
1972年 | 3篇 |
1968年 | 5篇 |
1967年 | 2篇 |
排序方式: 共有1299条查询结果,搜索用时 0 毫秒
81.
Knudsen LB Gissler M Bender SS Hedberg C Ollendorff U Sundström K Totlandsdal K Vilhjalmsdottir S 《Acta obstetricia et gynecologica Scandinavica》2003,82(3):257-268
BACKGROUND: To analyze the trends in legally induced abortions among women younger than 30 years in the five Nordic countries, Denmark, Finland, Iceland, Norway and Sweden, since the liberalized abortion laws came into force. METHODS: Data stem from national registrations of vital events. Some have been published in the national vital statistics while others have been retrieved for this study. General and age-specific abortion rates are used to analyze the trends. Further, an index has been calculated by dividing the age-specific abortion rates by the Nordic average. RESULTS: The analysis reveals an overall reduction in the general abortion rates in the Nordic countries, apart from Iceland. The rates have been highest in Denmark and Sweden and lowest in Finland since the early 1980s. In the mid-1980s, the abortion rates increased among 15-19-year-old women in Sweden and among 20-24-year-old women in Denmark, Norway and Sweden, followed by a reduction. In Iceland the very low age-specific abortion rates for all age groups under 30 years at the beginning of the study period increased and Iceland had the highest rate for 15-19-year-old women in the late-1990s. CONCLUSIONS: The relatively low abortion rates in Finland demonstrate effective preventive efforts, although the recent increase challenges further studies on the relationship between abortion rates and counseling activities. The rise in abortion rates in Iceland indicate a need for improved sex education, contraceptive services and availability of contraceptive methods for young people. 相似文献
82.
83.
The pharmacokinetics of D,L-3-hydroxy-3-ethyl-3-phenylpropionamide (HEPP), an investigational anticonvulsant drug, was evaluated in nonpregnant and in pregnant rats on gestation day (GD) 7, 12, and 21 after an intraperitoneal (i.p.) dose of 50mg/kg. Maternal-fetal disposition in the GD21 group was also evaluated. In all groups, HEPP was rapidly absorbed and the disposition was well described by an open two-compartment kinetic model. The most pronounced effects of pregnancy on the kinetics of HEPP were observed at GD21 in which significant increases in the first-order hybrid disposition rate constants alpha and beta, with corresponding decreases in half-lives were observed. Gestation also affected the intercompartmental transfer rate constants k(12) and k(21), specially at GD12 and at GD21. These changes could be associated with the physiologic increases in blood flow and cardiac output of pregnancy. There was also a slight decrease in the apparent volume of distribution at GD21, and a progressive decrease in the clearance values normalized by the body weight. No other significant differences in kinetic parameters were observed. On GD21, HEPP rapidly transfers from maternal blood to fetuses, to reach concentrations in the placenta and fetuses slightly higher than those of the maternal plasma (fetal:maternal ratio ranging from 1.07 to 1.45). After equilibrium, the concentrations in maternal, placental, and fetal tissues decreased in parallel. 相似文献
84.
Eye irritation and environmental factors in the office environment--hypotheses, causes and a physiological model 总被引:2,自引:0,他引:2
Wolkoff P Skov P Franck C Petersen LN 《Scandinavian journal of work, environment & health》2003,29(6):411-430
The study reviews eye irritation using a multidisciplinary approach. Potential risk factors and objective gender differences are identified, and possible hypotheses for eye irritation caused by indoor air pollution are discussed. Eye irritation depends somewhat on destabilization of the outer-eye tear film. An integrated physiological risk model with blink frequency, destabilization, and break-up of the eye tear film as inseparable phenomena may explain eye irritation among office workers in terms of occupational, climate, and eye-related physiological risk factors. Certain volatile organic compounds that are both chemically reactive and airway irritants may cause eye irritation. If airborne particles alone should destabilize the tear film and cause eye irritation, their content of surface-active compounds must be high. Personal factors (eg, use of contact lenses, eye make-up, and certain medication) may also affect destabilization of the tear film and possibly result in more eye symptoms. 相似文献
85.
High leptin levels are associated with stroke 总被引:11,自引:0,他引:11
Söderberg S Stegmayr B Ahlbeck-Glader C Slunga-Birgander L Ahrén B Olsson T 《Cerebrovascular diseases (Basel, Switzerland)》2003,15(1-2):63-69
BACKGROUND AND PURPOSE: Leptin, an important hormone for body weight regulation, may be involved in the pathogenesis of cardiovascular manifestations of obesity. We tested whether leptin may be an independent risk marker for stroke in a case-referent study. METHODS: Definitive acute stroke events, defined by MONICA criteria, were identified from October 1, 1995 to April 30, 1999. Referents without known cardiovascular disease were randomly selected from a population census. Patient characteristics were taken from hospital files and leptin was analyzed in stored samples. Logistic regression analysis was used to determine possible differences in leptin levels between groups. RESULTS: One hundred and thirty-seven cases with ischemic stroke and 69 cases with hemorrhagic stroke were identified. In comparison with referents, male patients with stroke had significantly higher leptin levels. Both male and female stroke patients had increased blood pressure compared with the referents. In multivariate analyses, high leptin levels were associated with both ischemic (OR = 4.89; 95% CI: 1.89-12.62) and hemorrhagic (OR = 3.86; 95% CI: 1.13-13.16) stroke in men, and with ischemic stroke in women (OR = 4.10; 95% CI: 1.45-11.62). The combination of high leptin levels and increased blood pressure (systolic or diastolic) was associated with a strong positive interaction in males with hemorrhagic stroke. CONCLUSION: Leptin may be an important link for the development of cerebrovascular disease in the insulin resistance syndrome in men. 相似文献
86.
Govender Thirumala Ehtezazi Touraj Stolnik Snjezana Illum Lisbeth Davis Stanley S. 《Pharmaceutical research》1999,16(7):1125-1131
Purpose. Due to the importance of drug-polymer interactions in, inter alia, drug loading/release, supramolecular assemblies and DNA delivery for gene therapy, the aim of this study was therefore to establish the mechanism of interaction between a model polymer (Polyacrylic acid, PAA) and a model drug (procaine HCl).
Methods. This was performed by studying the effect of salt (KCl) concentration on their heat released values using Isothermal Titration Microcalorimetry (ITM). The integrated released heat data were computer fitted to a one class binding model and the thermodynamic parameters (Kobs, H, and N) were determined.
Results. As the KC1 concentration was increased, Kobs decreased thus establishing the salt dependence of the interaction. The linear variation of Gobs with Sobs indicated that their interaction was entropically driven. The stoichiometry of the interaction was calculated to be one procaine molecule per monomer of PAA. Dissection of the total observed free energy at each KC1 concentration indicated that the contribution of the non-electrostatic attractions to the interaction of PAA with procaine HC1 was greater than those of the electrostatic attractions.
Conclusions. We have shown that the interaction between PAA and procaine HC1 is dependent upon the presence of counterions (monovalent ions) and is mainly entropically driven. The calculated stoichiometry indicated that one procaine HC1 molecule neutralised one carboxylic acid group on PAA. Although electrostatic interactions were necessary for initiating complex formation, the non-electrostatic forces were dominant in stabilising the PAA-procaine HC1 complex. 相似文献
87.
Yossi Tsadok Yael Petrank Sebastian Sarvari Thor Edvardsen Dan Adam 《Computerized medical imaging and graphics》2013,37(7-8):500-511
Segmentation of cardiac magnetic resonance imaging is considered an important application in clinical practice. An automatic algorithm is proposed for segmentation of both endocardial and epicardial boundaries, in long-axis views. The data consisted of 126 patients, yielding 1008 traces. Estimated clinical parameters were highly correlated to gold standard measurements. The error between the automatic tracing and the gold standard was not significantly different than the error between two manual observers. In conclusion, a tool for segmenting the myocardial boundaries in the long-axis views is proposed, which works well, as demonstrated by the validation performed using a clinical dataset. 相似文献
88.
Karsten Thomsen Lisbeth Nilas Torben Mogensen Claus Christiansen 《European journal of nuclear medicine and molecular imaging》1986,12(7):342-345
Two metods of estimating bone turnover were investigated. The 24 h whole body retention (WBR) of intravenously injected 99mTc methylene disphosphonate (99mTc-MDP), a precise, accurate, and generally accepted method, was compared with a new, simple, measurement involving assessment of the 24 h urinary excretion (UE) of 99mTc-MDP. The WBR and UE were measured in 50 normal subjects, 10 patients with thyrotoxicosis, and 10 patients with chronic renal failure. The precision was 4.8% and 2.7%, respectively, and the two methods were highly significantly correlated (r=0.99, SEE=2.9%, p<0.001). In addition, urinary 99mTc-MDP excretions at 0 h–4 h (UE4) and 0 h–8 h (UE8) after injection were calculated in 49 subjects. The estimation of WBR from UE4 or UE8 was considerably poorer than from UE (for UE4: r=-0.83, SEE=8.7%, and for UE8: r=-0.90, SEE=6.8%) and the precision of UE4 and UE8 was 7.2% and 7.8%, respectively, and greater than those of both UE and WRR. It is concluded that the UE bone turnover measurement may become a simple, radiation dose-saving method to diagnose and monitor the treatment of metabolic bone diseases. 相似文献
89.
Andres Troelsen Jens K. Møller Lars Bolvig Thomas Prynø Lisbeth N. Pedersen Kjeld Søballe 《The Journal of arthroplasty》2010
Invasive infection with animal-associated bacteria, Erysipelotrix rhusiopathiae, is unusual and has, to our knowledge, never been described as the cause of infected total hip arthroplasty. We describe how an infected total hip arthroplasty caused by these bacteria is eradicated using standard surgical and antibiotic treatment. Before 2-stage revision surgery, the patient had persistent groin pain, elevated C-reactive protein, radiographic periprosthetic osteolysis, excessive intra-articular fluid, and periprosthetic activity accumulation on the white cell scan. The patient was treated with benzylpenicillin after confirmed sensitivity of E rhusiopathiae diagnosed by culture of five tissue samples and polymerase chain reaction of the prosthetic sonicate sample. Sixteen weeks after the last stage of revision surgery, there were no signs of reoccurring infection. 相似文献
90.
David Langton Bernard F. Jover Lisbeth Trigg Meryl Fullerton Duncan W. Blake Barry P. McGrath 《Clinical and experimental pharmacology & physiology》1989,16(12):939-951
1. A biventricular, low-output congestive cardiomyopathy was induced in 19 rabbits by administering adriamycin (16 mg/kg). The effects of alpha-rat atrial natriuretic peptide (ANP) infused at 0.1, 0.2 and 0.4 micrograms/kg per min, were then examined in terms of (i) central haemodynamics (ii) regional blood flow (iii) renal function and (iv) plasma norepinephrine and plasma renin. 2. In this dose range, ANP produced progressive and significant falls in stroke volume, cardiac output and mean arterial pressure, owing to a fall in venous return. The heart rate response to this was blunted. 3. Using radiolabelled microspheres, significant falls in the perfusion of cutaneous, gastrointestinal and musculoskeletal tissues were observed, due to reduced vascular conductances in these beds. These changes were accompanied by activation of the sympathetic nervous system as evidenced by a progressive rise in plasma norepinephrine. A significant increase in plasma renin was only observed with the highest infusion of ANP. 4. Renal blood flow was maintained in the face of a falling mean arterial pressure and cardiac output, but diuretic and natriuretic effects were absent. 5. It was concluded that the dominant influence of ANP infusion in this model of heart failure appeared to be a reduction in cardiac preload with detrimental overall haemodynamic consequences. 相似文献