全文获取类型
收费全文 | 1928篇 |
免费 | 129篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 85篇 |
妇产科学 | 13篇 |
基础医学 | 187篇 |
口腔科学 | 43篇 |
临床医学 | 234篇 |
内科学 | 403篇 |
皮肤病学 | 66篇 |
神经病学 | 167篇 |
特种医学 | 176篇 |
外科学 | 214篇 |
综合类 | 40篇 |
一般理论 | 2篇 |
预防医学 | 191篇 |
眼科学 | 24篇 |
药学 | 111篇 |
中国医学 | 1篇 |
肿瘤学 | 96篇 |
出版年
2023年 | 10篇 |
2022年 | 16篇 |
2021年 | 31篇 |
2020年 | 28篇 |
2019年 | 45篇 |
2018年 | 53篇 |
2017年 | 40篇 |
2016年 | 45篇 |
2015年 | 44篇 |
2014年 | 66篇 |
2013年 | 74篇 |
2012年 | 96篇 |
2011年 | 94篇 |
2010年 | 56篇 |
2009年 | 60篇 |
2008年 | 90篇 |
2007年 | 124篇 |
2006年 | 94篇 |
2005年 | 94篇 |
2004年 | 87篇 |
2003年 | 85篇 |
2002年 | 70篇 |
2001年 | 37篇 |
2000年 | 17篇 |
1999年 | 39篇 |
1998年 | 46篇 |
1997年 | 42篇 |
1996年 | 53篇 |
1995年 | 39篇 |
1994年 | 40篇 |
1993年 | 25篇 |
1992年 | 15篇 |
1991年 | 16篇 |
1990年 | 12篇 |
1989年 | 26篇 |
1988年 | 23篇 |
1987年 | 25篇 |
1986年 | 24篇 |
1985年 | 24篇 |
1984年 | 14篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1981年 | 18篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1976年 | 12篇 |
1973年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有2065条查询结果,搜索用时 15 毫秒
1.
2.
PC Chamyal A Mehta SL Ojha JR Bhardwaj 《Indian journal of otolaryngology and head and neck surgery》1991,43(1):26-27
Primary tuberculous pathology in nasolpolypi is a rare condition. A case of bilateral ethmoidal polypi with tubercular lesion diagnosed on histopathologlcal examination is being reported and the available relevant literature has been reviewed. 相似文献
3.
Adenosine instead of supranormal potassium in cardioplegic solution improves cardioprotection. 总被引:1,自引:0,他引:1
?yvind Jakobsen Stig Muller Erling Aarsaether Tor Steensrud Dag G S?rlie 《European journal of cardio-thoracic surgery》2007,32(3):493-500
OBJECTIVE: To determine whether adenosine instead of supranormal potassium in cold crystalloid cardioplegia gives satisfactory cardiac arrest and improved cardioprotection. Cold crystalloid cardioplegia with adenosine, procaine and magnesium (A) was compared with standard cold crystalloid hyperkalemic cardioplegia (K). METHODS: Sixteen pigs were randomized to receive either cold K (n=8) or A (n=8), where hyperkalemia was substituted with 1.2 mM adenosine. The cold (6 degrees C) cardioplegia was given intermittently and antegradely, with an aortic cross-clamp time of 1 h. Hemodynamic data was continuously measured and pressure-volume conductance catheters were used to determine global left ventricular systolic and diastolic function. Coronary flow and O2 content differences allowed determination of left ventricular energetics. Blood samples, and left ventricular microdialysis were used to measure parameters of ischemia. Measurements were done at 1 and 2 h after cross-clamp release. RESULTS: Mean arterial pressure was reduced with 55 mmHg (standard deviation, SD: 19) in the K group versus 30 mmHg (SD: 14) in the A group 2 h after cross-clamp release (p=0.030). Left ventricular contractility expressed as slope of the preload recruitable stroke work index (Mw) was reduced to 53% (SD: 14) in the K group versus 78% (SD: 23) in the A group 2h after cross-clamp release (p=0.046). Reduction of maximum of first derivate of pressure with respect to time (dP/dtmax) was 804 mmHg/s (SD: 189) in the K group versus 538 mmHg/s (SD: 184) in the A group (p=0.033). The slope of the myocardial oxygen consumption-pressure volume area was at 2 h reperfusion increased from 1.37 (SD: 0.64) to 2.86 (SD: 1.27) in the K group, whereas no shift was detected in the A group (p=0.019). Cardiac troponin T measured in the coronary sinus 1 h after cross-clamp release was 1.25 microg/l (SD: 0.64) in the K group versus 0.73 microg/l (SD: 0.31) in the A group (p=0.046). CONCLUSION: Adenosine instead of supranormal potassium in cold crystalloid cardioplegia gives satisfactory cardiac arrest, improves post cardioplegic left ventricular systolic function and efficiency, and attenuates myocardial cell damage. 相似文献
4.
Knut E Kj?rstad Dag Ole Nordhaug Christian Korvald Stig Müller Tor Steensrud Truls Myrmel 《European journal of cardio-thoracic surgery》2007,31(4):677-684
OBJECTIVE: The time constant of mechanical restitution (T((MRC))), proposed to reflect changes in calcium release and uptake, has been shown to increase in left ventricular (LV) failure, and might have a potential as an index of contractile function. However, in vivo studies of the effect on T((MRC)) of changing loading conditions in the normal and failing heart have not been reported. Consequently, in this study, we tested the hypothesis that the increase in T((MRC)) in vivo is independent of preload and afterload. METHODS: Left ventricular pressure-volume loops were assessed at baseline in eight open chest pigs using the combined pressure-volume conductance catheter technique during right atrial pacing at 120b/min. Mechanical restitution curves (MRC) were constructed during four different loading conditions in all eight animals: uninfluenced load, reduced preload (balloon catheter in v. cava inferior), increased afterload (balloon catheter in descending aorta), and increased preload combined with reduced afterload (aortocaval shunting). Acute LV failure was then induced by microembolization through the left main coronary artery, and the experimental protocol was repeated. Contractile response was defined as the maximal first derivative of pressure (dP/dt(max)), and T((MRC)) was calculated using a least square approximation algorithm. RESULTS: Hemodynamic data 30min after microembolization showed decreased mean arterial pressure (98+/-14-67+/-10mmHg, (mean+/-SD) P<0.0001) and dP/dt(max) (1482+/-193-1001+/-125mmHg/s, P=0.001). Stroke volume decreased from 30+/-5 to 20+/-5ml (P<0.0001) compared to baseline, and preload recruitable stroke work decreased from 52+/-7 to 31+/-10mmHg (P=0.002). T((MRC)) increased in all eight animals after induction of LV failure at all loading conditions. There was no difference between the different loading conditions at baseline, nor at LV heart failure, but T((MRC)) increased significantly after the induction of heart failure (ANOVA, two ways). CONCLUSIONS: We have shown that the left ventricular T((MRC)) increases after developed heart failure. The increase in T((MRC)) was independent on loading conditions and thus have a potential for a contractility index. 相似文献
5.
Oral health was examined in a random sample of 1377 people in three 70-year-old cohorts studied within 5-yr intervals. During the studied period 1971-1983 the prevalence of toothlessness decreased from 52 to 34%. Toothlessness in men was more common in smokers, 48%, and ex-smokers, 32%, than in non-smokers, 20%. Eichner's index was used as a measurement of dental invalidity. This index showed a worse dental state among smokers and ex-smokers compared to non-smokers. Multivariate analyses indicated that tobacco smoking was a major independent risk factor for tooth loss in elderly men. 相似文献
6.
7.
Anders Baerheim Per Hjortdahl Are Holen Tor Anvik Ole Bernt Fasmer Hilde Grimstad Tore Gude Terje Risberg Per Vaglum 《BMC medical education》2007,7(1):35
Background
Communication training builds on the assumption that understanding of the concepts related to professional communication facilitates the training. We know little about whether students' knowledge of clinical communication skills is affected by their attendance of communication training courses, or to what degree other elements of the clinical training or curriculum design also play a role. The aim of this study was to determine which elements of the curriculum influence acquisition of knowledge regarding clinical communication skills by medical students. 相似文献8.
目的:对临床确诊糖尿病患同时测定血清葡萄糖(Glu)及糖化血清蛋白(GSP)的含量,观察二的关系,以及糖化血清蛋白水平对于评价近期(2—3周)糖尿病患血糖在体内变化的临床意义进行了观察。方法:血清葡萄糖、糖化血清蛋白测定均采用酶法测定。结果:178例糖尿病患Glu、GSP均正常3l例占17.4%;Glu、GSP均增高107例占60.1%;Glu正常、GSP增高15例占8.43%;Glu增高、GSP正常25例占14%。结论:糖化血清蛋白的含量不受即时血糖的影响,二的变化不成比例性,对评价糖尿病患2~3周病情的控制是一项灵敏可靠的指标,尤其对于住院病人的治疗与监控有一定的意义。 相似文献
9.
Alf Tor Karlsen 《American journal of orthodontics and dentofacial orthopedics》2004,125(5):597-606
The upper cervical spine and face were compared longitudinally from 6 to 15 years of age in 2 groups of children with low (n = 16) and high (n = 14) MP-SN angles. The purpose of the study was to assess morphological and incremental associations between the vertical development of the cervical spine and the face in subjects with varying vertical facial patterns. Morphological associations were not detected during the observation period. Long faces were found on children with short necks, and short, square faces on those with long necks. Vertical growth of the upper cervical spine and face were weakly correlated in the 6-to-12-year period but strongly correlated later during puberty. The vertical distance between gonion and the body of the second cervical vertebra was remarkable for its constancy during childhood and puberty, indicating that gonion and the second cervical vertebra body were anatomically interrelated. This anatomical relationship strongly suggests that a mutual relationship also exists between vertical growth of the upper cervical spine and the face, especially the lower face. In addition, the lower face had the ability for independent vertical growth that was not coordinated with vertical cervical growth. This was the case in the 6-to-12-year period, but not later. 相似文献
10.