全文获取类型
收费全文 | 2468篇 |
免费 | 108篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 169篇 |
妇产科学 | 310篇 |
基础医学 | 188篇 |
口腔科学 | 64篇 |
临床医学 | 184篇 |
内科学 | 487篇 |
皮肤病学 | 31篇 |
神经病学 | 137篇 |
特种医学 | 94篇 |
外科学 | 478篇 |
综合类 | 46篇 |
一般理论 | 1篇 |
预防医学 | 53篇 |
眼科学 | 53篇 |
药学 | 124篇 |
中国医学 | 7篇 |
肿瘤学 | 98篇 |
出版年
2023年 | 18篇 |
2022年 | 30篇 |
2021年 | 43篇 |
2020年 | 29篇 |
2019年 | 46篇 |
2018年 | 60篇 |
2017年 | 45篇 |
2016年 | 68篇 |
2015年 | 82篇 |
2014年 | 83篇 |
2013年 | 143篇 |
2012年 | 180篇 |
2011年 | 177篇 |
2010年 | 95篇 |
2009年 | 118篇 |
2008年 | 186篇 |
2007年 | 225篇 |
2006年 | 201篇 |
2005年 | 199篇 |
2004年 | 161篇 |
2003年 | 136篇 |
2002年 | 98篇 |
2001年 | 45篇 |
2000年 | 30篇 |
1999年 | 33篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1982年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有2588条查询结果,搜索用时 31 毫秒
991.
Turhan S Tulunay C Ozduman Cin M Gursoy A Kilickap M Dincer I Candemir B Gullu S Erol C 《The Journal of clinical endocrinology and metabolism》2006,91(9):3490-3493
INTRODUCTION: The effects of l-thyroxine (l-T(4)) replacement for subclinical hypothyroidism (SH) on right ventricle (RV) functions has not been previously studied by means of pulsed wave tissue Doppler imaging (PWTDI). We investigated the effects of l-T(4) therapy on RV function in patients with SH using PWTDI. PATIENTS AND METHODS: Fifty-three patients with newly diagnosed SH and 25 controls were evaluated by standard echocardiography and PWTDI. After euthyroidism was restored by l-T(4), measurements were repeated. Myocardial systolic wave (S(m)) velocity, isovolumic acceleration (IVA), myocardial precontraction time (PCT(m)), and PCT(m) to contraction time (CT(m)) ratio were calculated as systolic indices. Early (E(m)) velocity, late (A(m)) velocity, E(m) to A(m) ratio, and myocardial relaxation time (RT(m)) were determined as diastolic measurements. RESULTS: S(m) was similar in patients and controls, whereas IVA was significantly lower in patients with SH (P < 0.001). SH patients had significantly decreased E(m) velocity, whereas A(m) velocity and E(m) to A(m) ratio did not differ. PCT(m) and RT(m) were significantly longer, and PCT(m) to CT(m) ratio was significantly higher in patients (P = 0.002, P = 0.002, P < 0.001, respectively). S(m) velocities were similar before and after l-T(4) replacement, whereas IVA significantly increased after therapy (P < 0.001). E(m) tended to increase (P = 0.05), whereas A(m) and E(m) to A(m) ratio were not changed. PCT(m), PCT(m) to CT(m) ratio, and RT(m) decreased significantly (P < 0.001 for all). CONCLUSIONS: SH is associated with RV systolic and diastolic dysfunction, and l-T(4) treatment improves these abnormalities. PWTDI, especially IVA, may be a suitable tool for the early detection of RV systolic dysfunction. 相似文献
992.
Guven MA Kilinc M Batukan C Ekerbicer HC Aksu T 《Archives of gynecology and obstetrics》2006,274(6):333-337
Objective Our aim was to investigate the association between total serum homocysteine, vitamin B12 and folate levels in pregnant women with gestational diabetes mellitus (GDM), glucose intolerance and compare them with those of glucose tolerant pregnant women.Materials and methods Serum homocysteine, vitamin B12 and serum folate levels were prospectively measured in a total of 223 pregnant women who were grouped according to their status of glucose tolerance as gestational diabetes (abnormal 1-h and 3-h glucose tolerance test; n = 30), glucose intolerant (abnormal 1-h, but normal 3-h glucose tolerance test; n = 46) or normal controls (normal 1-h glucose test; n = 147). Results Mean serum homocysteine concentration of women in gestational diabetes, glucose intolerants and normal controls at 24–28 weeks of gestation was 9.0 ± 3.1, 8.1 ± 2.5 and 7.4 ± 1.6 μmol/l, respectively. The only statistically difference in homocysteine levels was observed between women with gestational diabetes and normal controls (P < 0.01). However, no difference was observed for vitamin B12 and folate levels.Conclusion Second trimester serum homocysteine concentrations are higher among women with GDM, as compared to normal controls. 相似文献
993.
OBJECTIVE: To determine the development and the localization of the ovaries during the fetal period. MATERIAL AND METHODS: One hundred and fifty-four ovaries obtained from 77 human fetuses aged between 9 and 40 weeks of gestation were used in this study. Firstly, the shapes and the positions of the ovaries were established. Second, the localization of the ovaries with respect to linea terminalis, ureters, and the iliac arteries were determined. Finally, the dimensions and the weight of the ovaries were measured. FINDINGS: In the fetal period, the ovaries were most commonly almond shaped and had an oblique orientation. In the 1st trimester the midpoint of the long axis of the fetal ovaries were at the level of linea terminalis. In the 2nd and 3rd trimester and full-term fetuses, it was observed that the ovaries were not in ovarian fossa, suggesting that descensus ovary was in progression during these times. During the intrauterine period, the ovaries were most commonly located anterior to the ureters and over the common iliac artery, only to migrate to its final location between the internal and external iliac arteries towards the end of the 40th week. CONCLUSION: We found that the ovaries did not assume the position of the adults at the end of the fetal period, rather continued its descent after the birth. We believe our findings about the fetal ovaries will be useful in obstetrics, fetal pathology, and forensic pathology. 相似文献
994.
Mendilcioglu I Ozcan M Bagci G Simsek M Kursun S Luleci G Taskin O 《Fetal diagnosis and therapy》2006,21(1):65-67
OBJECTIVE: We report on a case of a triploidy in one fetus of a twin pregnancy who presented with the findings of growth discordance. METHODS: Three weeks' difference between fetuses in ultrasonographic measurements in the first trimester was observed in a twin pregnancy following intracytoplasmic sperm injection (ICSI) treatment for male infertility. Hydrocephaly developed in the growth-discordant fetus subsequently. Amniocentesis for both fetuses and selective feticide for the abnormal one was performed at 19 weeks' gestation through a single insertion. Fetal karyotype of the abnormal one was 69,XXX and the healthy one was 46,XX. CONCLUSION: Early developed growth discordance in a twin pregnancy may be a sign of chromosomal abnormality such as triploidy. Those cases should be karyotyped without delay to decrease preterm delivery risk of possible selective feticide. 相似文献
995.
Although N-methyl-D-aspartate (NMDA) receptors of the hippocampus are mainly associated with learning and memory that might occur "on-line" during sharp waves (SPWs) and theta-rhythm, the participation of hippocampal NMDA receptors in sleep-related processes has not been well studied. In this study, the activity of sleep episodes, hippocampal SPWs and theta-rhythm were recorded in rats received a repeated infusion of NMDA receptor antagonist, D,L-2-amino-5-phosphonopentanoic acid (AP5), into the lateral ventricle in a 5-h daytime sleep. The first trial AP5 infusion (30 mM/2 microl) did not change measures of the activity of slow wave sleep (SWS), paradoxical sleep (PS) and awake episodes, but induced a delay in the latency of the first onset of PS; in the hippocampal EEG, it increased the amplitude of SPWs within SWS and shifted the amplitude/spectral power of theta-rhythm from high to low frequency within PS. The repeated AP5 infusion augmented the activity of SWS, and impaired PS and awake episodes; in the EEG-sleep picture, it maintained high scores of SPWs with the complete blockade of theta-rhythm generation. When AP5 rat was woken, the theta-rhythm was seen during exploratory behavior. These findings provide evidence that hippocampal NMDA receptors via SPWs or directly associated with the synaptic events of theta-rhythm generation are critical for the PS activities. 相似文献
996.
Duzcan F Aybek Z Tepeli E Caner V Cetin GO Aybek H Bagci H 《The Journal of reproductive medicine》2006,51(6):489-492
OBJECTIVE: A large number of studies have shown that the prevalence of somatic chromosome abnormalities detectable with karyotyping is higher in infertile men. However, a normal somatic karyotype does not exclude the chance of having low level mosaicism. STUDY DESIGN: Eleven men with severe oligozoospermia and 10 healthy, fertile men were included in this study. All the patients had severe oligozoospermia with sperm counts < or =3,000,000/ mL. All participants had normal physical findings and testicular volume. The probe for dual-color fluorescence in situ hybridization consisted of an alpha satellite sequence in the centromeric region of chromosome X (DXZ1) and satellite III DNA at the Yq12 region of chromosome Y (DYZ1). RESULTS: The sex chromosome aneuploidy rate was significantly higher in subjects than in controls (p<0.001). The median incidence of sex chromosome aneuploidy in the oligozoospermic group was 4.5% (range, 0.8-7.3%), while in the control group it was 0.7% (range, 0.2-1.2%)., CONCLUSION: The incidence of aneuploidy in somatic cells is significantly greater in oligozoospermic men than in normal controls. That may suggest that chromosome instability is a result of altered genetic control during mitotic cell division. Our results demonstrate that men with oligozoospermia have an elevated risk for sex chromosome abnormalities in their somatic cells. 相似文献
997.
Severity of respiratory distress syndrome (RDS) and mechanical ventilation may affect the endogenous cortisol secretion in preterm infants. The aim of this study was to compare the serum cortisol concentrations of a relatively large and mature group of preterm infants with RDS who are ventilated or nonventilated and control preterm infants without RDS. Infants (group I) of comparable gestational ages without RDS served as controls. Infants with RDS who did not need ventilator support and surfactant therapy were considered to have mild RDS (group II). Those requiring mechanical ventilation and surfactant therapy were considered to have severe RDS (group III). Serum cortisol levels were determined after birth and on day 3 of life. The study groups consisted of 79 preterm infants with gestational ages ranging from 31 to 36 weeks, and birthweights ranging from 1086 to 1685 g. All preterm infants showed high cortisol levels after delivery regardless of respiratory distress (group I, n = 25, 34.1 +/- 10.7 microg/dL; group II, n = 23, 33.6 +/- 12.0 microg/dL; and group III, n = 31, 36.4 +/- 12.3 microg/dL). In group III, the cortisol levels (50.8 +/- 16.8 microg/dL) were higher than in group II (40.4 +/- 10.5 microg/dL) and in controls (22.0 +/- 7.2 microg/dL), and the cortisol levels of controls were lower than in group II on day 3 of life. Although the cortisol levels in severe and mild RDS infants increased significantly from their corresponding levels on day 1, they decreased in controls. The cortisol levels on day 3 of life were not significantly different in infants with poor outcome compared with infants with better outcome. Severity of RDS and mechanical ventilation were related to serum cortisol levels of preterm infants. Our study suggests that large and mature preterm infants who are ventilated and/or more severely ill release more cortisol than those less severely ill. 相似文献
998.
The larvicidal activity of chlorpyrifos-methyl and temephos was evaluated against Culex pipiens L. (Diptera: Culicidae) in septic tanks in Antalya, Turkey. Chlorpyrifos-methyl (Pyrifos MT 25 emulsifiable concentrate [EC] ) was evaluated at application rates of 0.04, 0.08, and 0.12 mg active ingredient (AI)/liter, and temephos (Temeguard 50 EC) was evaluated at 0.02, 0.04, and 0.06 mg (AI)/liter during a 21-d study. Generally, overall larval reduction in septic tanks from single- and multifamily dwellings treated with either larvicide was significantly greater than pretreatment levels and control tanks for the duration of the study. At 14 d posttreatment, duration of control was greatest in multifamily tanks treated with chlorpyrifos-methyl at the highest application rate with similar levels of control through 21 d for single-family dwellings (range 97-100%). Septic tanks from both types of family dwellings treated at the highest application rate of temephos resulted in >90% reduction through day 21 (range 91-100%). Laboratory bioassays of septic tank water treated at field application rates, without daily dilution, revealed that complete larval mortality was achieved for 21 d at each application rate and formulation. It is thought that daily addition of water and organic matter to the septic tanks in the single and multifamily dwellings influenced the duration of effectiveness of the larvicides. 相似文献
999.
Simvastatin treatment improves endothelial function and increases fibrinolysis in patients with hypercholestrolemia 总被引:1,自引:0,他引:1
Guven GS Atalar E Yavuz B Beyazit Y Kekilli M Kilicarslan A Sahiner L Oz G Ozer N Aksoyek S Haznedaroglu IC Sozen T 《Journal of the National Medical Association》2006,98(4):627-630
OBJECTIVES: Statins reduce cardiovascular events by cholesterol-lowering as well as nonlipid-related actions. Thrombin activatable fibrinolysis inhibitor (TAFI) is a recently identified independent risk factor of thrombosis. Endothelial dysfunction is also a strong predictor of cardiovascular events. The aim of this study was to assess the effects of simvastatin treatment on circulating TAFI concentrations and endothelial function in patients with hypercholesterolemia. METHODS: Thirty-five patients (19 female, mean age 48 +/- 7 years) with hyperlipidemia were recruited into the study. Simvastatin was administered, 40 mg daily, for eight weeks to all subjects. Study subjects did not receive any medication except for lipid-lowering therapy during the follow-up period. Endothelial function was evaluated by flow-mediated dilation (FMD) from the brachial artery of the patients. Plasma lipid parameters, TAFI levels and endothelial function were measured before and after simvastatin treatment. RESULTS: Treatment with simvastatin showed a significant decrement in plasma total cholesterol, LDL cholesterol and triglyceride levels (p<0.05). Plasma TAFI levels were also significantly decreased after simvastatin treatment [median 17.0 (range 0.4-93.7) mcg/mL versus median 6.9 (range 0.8-63.0) mcg/mL, p<0.001]. Mean FMD was measured 7.7 +/- 2.5% at baseline and significantly improved after treatment (13.0 +/- 1.4%) (p=0.001). CONCLUSION: Our findings of decreased TAFI levels may reflect the beneficial effect of simvastatin treatment on fibrinolysis, and improved endothelial function may suggest the improved future cardiovascular events in hyperlipidemic patients. 相似文献
1000.
Role of increased mean platelet volume (MPV) and decreased MPV/platelet count ratio as poor prognostic factors in lung cancer
下载免费PDF全文
![点击此处可从《The clinical respiratory journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)