全文获取类型
收费全文 | 523959篇 |
免费 | 27959篇 |
国内免费 | 810篇 |
专业分类
耳鼻咽喉 | 7185篇 |
儿科学 | 17297篇 |
妇产科学 | 14849篇 |
基础医学 | 77556篇 |
口腔科学 | 12996篇 |
临床医学 | 42268篇 |
内科学 | 105929篇 |
皮肤病学 | 12294篇 |
神经病学 | 41403篇 |
特种医学 | 18311篇 |
外国民族医学 | 142篇 |
外科学 | 74796篇 |
综合类 | 8732篇 |
现状与发展 | 1篇 |
一般理论 | 222篇 |
预防医学 | 40819篇 |
眼科学 | 11431篇 |
药学 | 36947篇 |
中国医学 | 1473篇 |
肿瘤学 | 28077篇 |
出版年
2021年 | 5627篇 |
2020年 | 3404篇 |
2019年 | 6058篇 |
2018年 | 10878篇 |
2017年 | 7436篇 |
2016年 | 7860篇 |
2015年 | 8856篇 |
2014年 | 10182篇 |
2013年 | 16233篇 |
2012年 | 24809篇 |
2011年 | 25229篇 |
2010年 | 13941篇 |
2009年 | 11353篇 |
2008年 | 22252篇 |
2007年 | 23986篇 |
2006年 | 22702篇 |
2005年 | 22112篇 |
2004年 | 21001篇 |
2003年 | 19449篇 |
2002年 | 18405篇 |
2001年 | 18919篇 |
2000年 | 19408篇 |
1999年 | 16501篇 |
1998年 | 3879篇 |
1997年 | 3494篇 |
1996年 | 3303篇 |
1995年 | 3154篇 |
1992年 | 11284篇 |
1991年 | 11143篇 |
1990年 | 10811篇 |
1989年 | 10404篇 |
1988年 | 9535篇 |
1987年 | 9146篇 |
1986年 | 8668篇 |
1985年 | 8267篇 |
1984年 | 6085篇 |
1983年 | 5245篇 |
1982年 | 3129篇 |
1979年 | 5583篇 |
1978年 | 4044篇 |
1977年 | 3494篇 |
1976年 | 3122篇 |
1975年 | 3606篇 |
1974年 | 4298篇 |
1973年 | 4333篇 |
1972年 | 4007篇 |
1971年 | 3824篇 |
1970年 | 3669篇 |
1969年 | 3453篇 |
1968年 | 3300篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
O Schouten J H H van Laanen E Boersma R Vidakovic H H H Feringa M Dunkelgrün J J Bax J Koning H van Urk D Poldermans 《European journal of vascular and endovascular surgery》2006,32(1):21-26
OBJECTIVE: To evaluate the effect of statins on aneurysm growth in a group of consecutive patients under surveillance for infrarenal aortic aneurysms (AAA). MATERIALS AND METHODS: All patients (59 statin users, 91 non-users) under surveillance between January 2002 and August 2005 with a follow-up for aneurysm growth of at least 12 months and a minimum of three diameter evaluations were retrospectively included in the analysis. Multiple regression analysis, weighted with the number of observations, was performed to test the influence of statins on AAA growth rate. RESULTS: During a median period of 3.1 (1.1-13.1) years the overall mean aneurysm growth rate was 2.95+/-2.8 mm/year. Statin users had a 1.16 mm/year lower AAA growth rate compared to non-users (95% CI 0.33-1.99 mm/year). Increased age was associated with a slower growth (-0.09 mm/year per year, p = 0.003). Female gender (+1.82 mm/year, p = 0.008) and aneurysm diameter (+0.06 mm/year per mm, p = 0.049) were associated with increased AAA growth. The use of non-steroidal anti-inflammatory drugs, chronic lung disease, or other cardiovascular risk factors were not independently associated with AAA growth. CONCLUSIONS: Statins appear to be associated with attenuation of AAA growth, irrespective of other known factors influencing aneurysm growth. 相似文献
42.
43.
D Yinon L Lowenstein S Suraya R Beloosesky O Zmora A Malhotra G Pillar 《The European respiratory journal》2006,27(2):328-333
Pre-eclamptic toxaemia (PET) may be associated with both endothelial dysfunction (ED) and sleep-disordered breathing (SDB). It was hypothesised that females with PET would demonstrate both SDB and ED, and that a correlation between these two would suggest a potential causative association. A total of 17 females with PET and 25 matched females with uncomplicated pregnancy were studied. They underwent a nocturnal ambulatory sleep study (using Watch_PAT100) and noninvasive evaluation of endothelial function utilising the reactive hyperaemia test (using Endo_PAT 2000). A higher ratio of post- to pre-occlusion pulse-wave amplitude (endothelial function index (EFI)) indicated better endothelial function. Females with PET had a significantly higher respiratory disturbance index (RDI) and lower EFI than controls (18.4+/-8.4 versus 8.3+/-1.3.h(-1), and 1.5+/-0.1 versus 1.8+/-0.1, respectively). Blood pressure significantly correlated with RDI and with EFI. EFI tended to correlate with RDI. In conclusion, these results suggest that both sleep-disordered breathing and endothelial dysfunction are more likely to occur in females with pre-eclamptic toxaemia than in females with uncomplicated pregnancies. The current authors speculate that respiratory disturbances contribute to the functional abnormality of the blood vessels seen in females with pre-eclamptic toxaemia, although causality cannot be determined based on this study. 相似文献
44.
Jean-Sébastien Fallu Jürgen Rehm Emmanuel N. Kuntsche Esther Grichting Neerav Monga Edward M. Adlaf Susan J Bondy Gerhard Gmel 《Sozial- und Pr?ventivmedizin》2006,8(1):363-372
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel
analysis among Swiss adolescents
Objective:
To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels. 相似文献45.
Jér?me Dumortier Marie-Claude Gagnieu Janine Salandre Olivier Guillaud Philipe Guillem Mustapha Adham Olivier Boillot 《Liver transplantation》2006,12(9):1342-1346
Gastrointestinal (GI) disorders are one of the main adverse events in patients treated by mycophenolic acid (MPA). The aim of this prospective study was to evaluate the effect of conversion from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) in liver transplant patients presenting GI side-effects Since January 2003, stable liver transplant patients receiving MMF and presenting GI disorders, without evidence of other origin than MMF were enrolled. Conversion was performed without a washout period at an equimolar daily dosage. Thirty-six patients were included after a median delay of 45 months after liver transplantation (LT) (16 women and 20 men, median age of 47 years). Diarrhoea was the main clinical symptom (n = 28, 77.7%). At the time of inclusion, patients were treated with MMF since 18 months (range 3-28) and GI disorders were known for 9 months (range 3-12). After a median follow-up of 12 months after conversion, GI disorders were resolved in 20 patients (55%), improved in 6 patients (17%) and not modified or worsened in 10 patients (28%). Our results strongly suggest that conversion from MMF to EC-MPS in liver transplant patients can improve gastrointestinal disorders in a majority of the patients, and therefore might be considered as the best therapeutic option. 相似文献
46.
L González-Bayón S González-Moreno G Ortega-Pérez 《European journal of surgical oncology》2006,32(6):619-624
The new treatment strategy for Peritoneal Surface Malignancy combines a cytoreductive surgery and perioperative intraperitoneal chemotherapy. Cytoreduction removes all macroscopic tumor. Intraperitoneal chemotherapy avoids implantation of microscopic residual tumor cells on intra-abdominal surfaces when it is administered intraoperatively and/or early in the postoperative period. Delivering cytotoxic drugs directly into the peritoneal cavity maximizes dose intensity and minimizes systemic toxicity. Hyperthermia is selectively cytotoxic for malignant cells and potentiates the effect of chemotherapy. Implementation of this procedure makes the perioperative personnel to face a risk of exposure to cytotoxic agents. Furthermore, peritonectomies and electro-evaporation of tumor nodules are performed with high voltage electrocautery, generating a large amount of surgical smoke during several hours. Inhalation of these fumes may be also a risk for healthcare workers. In this article, we analyse in depth these new risks of the operating room personnel, we review the literature, and we give guidelines for secure performance of cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy, as well as for early postoperative intraperitoneal chemotherapy administration. These new procedures are safe techniques for patients and healthcare workers provided adequate policies are adopted to avoid occupational exposure. 相似文献
47.
Eric W. Dickson MD Gary V. Doern PhD Leo Trevino PhD Michelle Mazzoni PhD Stephen O. Heard MD 《Academic emergency medicine》2003,10(10):1019-1023
OBJECTIVES: Patients undergoing emergent endotracheal intubation are at increased risk for developing pneumonia. Although numerous strategies have been investigated to reduce ventilator-associated pneumonia (VAP), the incidence of VAP and its associated mortality remains high. This investigation tested the hypothesis that LiquiVent (Alliance Pharmaceutical, San Diego, CA-LV) delivered antibiotics (via spray-dried microspheres-SDM) would improve survival in a rat model of descending gram-negative pneumonia. METHODS: Wistar rats (n = 49) were randomized to receive prophylaxis with 1). nothing (controls); 2). intramuscular (IM) tobramycin, 3). intratracheal LV plus SDM shells (vehicle), 4). intratracheal LV plus SDM shells plus IM tobramycin, or 5). intratracheal LV plus SDM containing 1 mg/kg of tobramycin. All interventions were given 24 hours before a bacterial challenge with 10(8) colony-forming units of intratracheal Klebsiella pneumoniae. Mortality at ten days was the sole outcome measure. Survival in individual groups was compared with controls by Fisher's exact test with Bonferroni correction for multiple comparisons. RESULTS: All animals in the control group died of pneumonia within ten days of bacterial inoculation (0% survival). Prophylaxis with either IM tobramycin or SDM vehicle plus IM tobramycin provided no protection (0% survival). This is in sharp contrast to the cohort receiving pretreatment with tobramycin-containing SDM delivered via LV, in which 60% of the animals survived to study completion (p < 0.05). CONCLUSIONS: Prophylaxis with SDM containing antibiotics delivered in low-dose LV provided significant protection in a rat model of descending gram-negative pneumonia. These data support the hypothesis that perfluorocarbon-delivered intratracheal antimicrobials may be useful in the prevention of VAP. 相似文献
48.
N. Sinis H. O. Rennekampff M. Haerle H. -E. Schaller 《European journal of plastic surgery》2006,28(8):507-512
Intraoperative and postoperative free flap monitoring by means of oxygen tension measurement was carried out in 11 patients. We used an invasive flexible microcatheter that allowed for measurement of oxygen tension in all types of free flaps. Two cases of the measured flaps were buried free flaps which do not allow monitoring by clinical assessment. All flaps monitored in this study survived. One case of displacement of the microcatheter occurred. In one patient, the tissue pO2 monitor successfully detected early vascular thrombosis with subsequent reoperation and salvage of the free flap. 相似文献
49.
50.
Rènée du Toit Katherine Soong Garry Brian Jacqueline Ramke 《Optometry and vision science》2006,83(8):582-588
PURPOSE: The advantages of a focometer (FOCOMETER) over other methods of refraction for use in developing countries are that it is lightweight, compact, relatively inexpensive, fairly quick, and easy to use with minimal training. This clinical trial compared the repeatability, validity, and ease of use of the focometer with an autorefractor. METHODS: The refractive status of the right eye of 80 participants was determined with an autorefractor (Canon RK3). Three measurements were also taken with the focometer. RESULTS: The spherical equivalent (M) of the focometer was 0.25 D more positive than the autorefractor (p < 0.001) and 84% of measurements were within 0.75 D of the autorefractor. The autorefractor detected astigmatism in 91% (73) of the eyes, whereas the focometer identified only 32% (26). The design of the clock target restricts cylinder axis accuracy to the nearest 15 degrees . There was evidence of a learning effect for the focometer: the second and third measurements were more repeatable in the untrained group. There were no differences between the mean (1.03 +/- 2.28) and third focometer (-1.05 +/- 2.32) measurements (p = 0.34). However, using the third focometer measurement, 94% of participants had visual acuities of at least 6/12(-2). CONCLUSIONS: This study highlighted the focometer's restricted power range, inaccuracy of astigmatism and axis determination, and dependence on subject understanding and compliance. Therefore, in most clinical settings, the focometer would not be adequate for quantifying refractive error, but the focometer spherical equivalent was within acceptable limits of the autorefractor, and the visual acuity with lenses determined by the focometer indicates its potential usefulness in public health settings, especially where only spherical ready-made spectacles are dispensed. There may be more cost-effective ways to determine refractive error in these circumstances. A potentially important enhancement in focometer methodology that improves its ease of use was identified: use only the third measurement for each eye. 相似文献