全文获取类型
收费全文 | 10430篇 |
免费 | 504篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 175篇 |
儿科学 | 210篇 |
妇产科学 | 184篇 |
基础医学 | 1748篇 |
口腔科学 | 228篇 |
临床医学 | 845篇 |
内科学 | 2096篇 |
皮肤病学 | 184篇 |
神经病学 | 1037篇 |
特种医学 | 645篇 |
外国民族医学 | 1篇 |
外科学 | 1259篇 |
综合类 | 74篇 |
预防医学 | 429篇 |
眼科学 | 253篇 |
药学 | 999篇 |
中国医学 | 64篇 |
肿瘤学 | 538篇 |
出版年
2022年 | 56篇 |
2021年 | 136篇 |
2020年 | 87篇 |
2019年 | 113篇 |
2018年 | 146篇 |
2017年 | 125篇 |
2016年 | 168篇 |
2015年 | 226篇 |
2014年 | 289篇 |
2013年 | 395篇 |
2012年 | 545篇 |
2011年 | 597篇 |
2010年 | 349篇 |
2009年 | 359篇 |
2008年 | 606篇 |
2007年 | 661篇 |
2006年 | 616篇 |
2005年 | 636篇 |
2004年 | 630篇 |
2003年 | 616篇 |
2002年 | 607篇 |
2001年 | 135篇 |
2000年 | 115篇 |
1999年 | 144篇 |
1998年 | 138篇 |
1997年 | 128篇 |
1996年 | 101篇 |
1995年 | 85篇 |
1994年 | 89篇 |
1993年 | 99篇 |
1992年 | 86篇 |
1991年 | 68篇 |
1990年 | 61篇 |
1989年 | 79篇 |
1988年 | 59篇 |
1987年 | 61篇 |
1986年 | 45篇 |
1985年 | 68篇 |
1984年 | 59篇 |
1983年 | 57篇 |
1982年 | 59篇 |
1981年 | 69篇 |
1980年 | 49篇 |
1979年 | 52篇 |
1978年 | 45篇 |
1977年 | 62篇 |
1976年 | 44篇 |
1975年 | 44篇 |
1973年 | 35篇 |
1963年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Philipp Sommer Charlotte Eitel Gerhard Hindricks Christopher Piorkowski 《Journal of interventional cardiac electrophysiology》2013,37(2):205-206
Recently, a new technology for nonfluoroscopic 4-D catheter tracking has been introduced (MediGuide). This system allows precise catheter visualization on prerecorded conventional fluoroscopy loops. We report about the first experience in atrial flutter ablation using a MediGuide-supported ablation catheter. For successful ablation besides the 6 s for loop acquisition, no further fluoroscopy was used. 相似文献
93.
Ding Yu Yuan Xueling Wang Yongcheng Wang Aiyuan Shi Xian Wang Lu Daniela Litscher Ingrid Gaischek Irmgard Th. Lippe Gerhard Litscher 《中医杂志(英文版)》2017,37(3):404-411
Objective
To investigate the possible advantages of acupotomy over sodium hyaluronate injection for the treatment of knee osteoarthritis (KOA).Methods
Twenty rabbits were divided randomly into four groups (n = 5 in each): a control group, model group, acupotomy group, and sodium hyaluronate injection group. The model, acupotomy, and sodium hyaluronate groups underwent anterior cruciate ligament transection plus partial medial meniscectomy. Sodium hyaluronate injection and acupotomy were administered to the respective groups from weeks 5 to 8, and samples of the tibial plateau and medial condyle of the femur were collected in week 9. Vascular endothelial growth factor (VEGF) expression was assessed in cartilage and subchondral bone by immunohistochemical staining.Results
Articular cartilage degeneration was less pronounced in the acupotomy compared with the model and sodium hyaluronate groups. VEGF expression levels in cartilage and subchondral bone were increased in the model group compared with the control group (P < 0.01), and acupotomy had a more pronounced therapeutic effect than sodium hyaluronate injection (P < 0.01).Conclusion
Acupotomy and sodium hyaluronate injection may both reduce degeneration in the cartilage and subchondral bone in KOA based on the results from a rabbit model, but acupotomy improved the histopathology and reduced the VEGF content more effectively than sodium hyaluronate injection, probably by reducing venous stasis and intraosseous pressure. Acupotomy may improve KOA by lowering VEGF. 相似文献94.
Menon AK Albes JM Oberhoff M Karsch KR Ziemer G 《The Annals of thoracic surgery》2002,73(5):1418-1423
BACKGROUND: Minimally invasive direct coronary artery bypass is an established clinical procedure for revascularization of the left anterior descending coronary artery. Mechanical stabilization and temporary occlusion is currently used to perform the anastomosis of the internal thoracic artery to the left anterior descending coronary artery. However, critical reduction of cardiac function can occur as a result of temporary ischemia. The purpose of this study was to evaluate whether ischemic sequelae can be avoided by using temporary intraluminal shunts and whether this alters early outcome. METHODS: Thirty-five patients underwent minimally invasive direct coronary artery bypass revascularization using a mechanical stabilizer. In group A (n = 20), the anastomotic site was temporarily occluded by tourniquets. In group B (n = 15), temporary intraluminal shunts were inserted into the anastomotic site without any occlusion of the left anterior descending coronary artery. Anastomosis of the internal thoracic artery to the left anterior descending coronary artery was performed in an identical fashion. A Swan-Ganz catheter was inserted, and transesophageal echocardiographic measurements were obtained for analysis of left ventricular (LV) function. Regional wall motion, cardiac index, stroke volume index, systolic and diastolic LV diameters, and fractional area change were measured during four periods: at the start of the operation (baseline), placement of the stabilizer (stabilization), left anterior descending coronary artery occlusion (occlusion) or insertion of temporary intraluminal shunts (shunt), and 30 minutes after reperfusion (reperfusion). Angiograms were obtained 4 to 6 days postoperatively. RESULTS: In group A, LV performance, cardiac index, stroke volume index, and fractional area change decreased during occlusion whereas systolic diameters increased. Almost two myocardial segments per patient developed severe hypokinesia in the perfusion area. These changes disappeared after 30 minutes of reperfusion, with increased LV function. In group B, LV function remained stable whereas hypokinetic wall motion was only detected in 2 patients. Early angiograms revealed 90% of the grafts were patent in group A versus 100% in group B. The need for percutaneous intervention during the first 6 months was 20% in group A versus 6.7% in group B. CONCLUSIONS: The use of temporary intraluminal shunts resulted in reduced acute ischemia and revealed wall motion abnormalities and maintained LV function. Furthermore, this technique suggests an improvement of early graft patency and a lower reintervention rate within the first 6 postoperative months. Thus, use of temporary intraluminal shunts appears to be superior to the occlusion technique early after minimally invasive direct coronary artery bypass procedures. 相似文献
95.
Milos G Gallo LM Sosic B Uebelhart D Goerres G Haeuselmann HJ Eich D 《Calcified tissue international》2011,89(3):228-233
Little is known about bone mineral density (BMD) in patients with heroin addiction and subsequent methadone substitution.
The goal of this study was to compare bone mass density of young HIV-negative women on long-term methadone treatment to a
local group of young healthy women. Eleven women (aged 20–29) with previous heroin dependence and current methadone substitution
(20–140 mg, median 60, daily) for 1.5–9 (median 3) years were compared to 30 healthy women (aged 20–28). Participants were
examined with dual-energy X-ray absorptiometry of the lumbar spine (L2–L4), of the total proximal hip area, and of the femoral
neck. Patients and controls had neither current nor lifetime underweight condition, had comparable ages at menarche, and did
not differ significantly in current body mass index (21.9 ± 4.0, respectively, 20.5 ± 1.5 kg/m2) in spite of a largely unhealthy lifestyle (cigarette, alcohol, and cocaine consumption in patients). Patients’ total-hip
parameters were marginally lower than those of controls (BMD P = 0.054, T score P = 0.049), whereas the femoral neck and lumbar spine parameters did not differ significantly between the two groups. Long-term
methadone substitution in HIV-negative women seems to slightly affect bone mass density. 相似文献
96.
Diederichs CG Staib L Glasbrenner B Guhlmann A Glatting G Pauls S Beger HG Reske SN 《Clinical positron imaging : official journal of the Institute for Clinical P.E.T》1999,2(3):131-136
This study was done to evaluate if the accuracy of FDG-PET concerning the differentiation of benign and malignant pancreatic masses differs for patients with and without elevated C-Reactive Protein (CRP). Three hundred-four patients (165 neoplasms, 98 chronic pancreatitis, and 41 benign lesions) received FDG-PET of the abdomen prior to planned resective surgery. CRP was unknown, normal, and elevated with 211, 71, and 22 patients, respectively. For differentiation of benign and malignant lesions, specificity was 87% for patients with unknown or normal CRP, and it was 40% for patients with elevated CRP (P < 0.01). Thirty-five percent of those patients with both a positive PET and elevated CRP were false positive. On the contrary, sensitivity was slightly higher in the group with elevated CRP (92% vs. 80%, NS). FDG-PET is a sensitive and specific test for patients with normal CRP, however, FDG-PET may be false positive if CRP is elevated. Proper patient selection is therefore important. CRP or other parameters indicative of active inflammation appear useful adjuncts for the interpretation of increased FDG-accumulation. 相似文献
97.
BACKGROUND: Rat coagulating gland epithelial cells export proteins by an apocrine secretion mode within membrane blebs arising from the apical plasma membrane. Using a pan-PMCA antibody, we have recently shown the plasma membrane Ca(2+)-ATPase (PMCA) being part of the apical plasma membrane of epithelial cells and incorporated into the aposomal membrane. The mRNA of PMCA isoforms 1 and 4 respectively, have been detected by RT-PCR in rat coagulating gland. METHODS: In order to identify which PMCA isoform is integrated into aposomes during apocrine secretion and whether or not PMCA export is influenced by androgens RT-PCR, in situ hybridization, Western blotting, and immunofluorescence experiments were performed. RESULTS: PMCA1b is the isoform which is expressed and located in the apical plasma membrane of coagulating gland epithelial cells and is integrated into the aposomal membrane. In contrast, PMCA4 mRNA and protein are restricted to the stroma. Androgen deprivation by castration within 14 days leads to an accumulation of PMCA1b in coagulating gland epithelium, while aposomes are not detected anymore. CONCLUSIONS: We showed for the first time that PMCA isoform 1b is released via aposomes of the epithelial cells of the rat coagulating gland and that the localization of PMCA1b in the epithelial cells is influenced by androgens. 相似文献
98.
Andreas Straub Daniela Schiebold Hans Peter Wendel Carole Hamilton Thomas Wagner Eckhard Schmid Klaus Dietz Gerhard Ziemer 《European journal of cardio-thoracic surgery》2008,34(3):641-647
Objective: Cardiac surgery employing cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) can induce coagulation disturbances and bleeding complications that may be especially severe in infants. A better understanding of the coagulopathy and a quick method for its evaluation would be helpful in the management of patients exposed to CPB and DHCA. This study aimed to monitor coagulation defects in congenital heart surgery using rotational thromboelastometry (ROTEM((R))), standard coagulation tests and platelet flow cytometry. Methods: The study comprised 10 infants undergoing surgery for congenital heart disease on CPB and DHCA. Blood was sampled at skin incision, after heparinisation during CPB (directly pre- and directly post-DHCA) and after protamine administration post-CPB. ROTEM((R)) using different reagents including a heparinase-containing assay to evaluate coagulation during heparinisation, APTT and INR, and flow cytometry to evaluate platelet activation were performed. Results: During CPB, the ROTEM((R)) indicated CPB-induced clotting factor depletion and platelet dysfunction that persisted after CPB and heparin neutralisation. ROTEM((R)) results were available within 15min and therefore much faster than standard tests. ROTEM((R))-guided specific blood product treatment resulted in satisfactory coagulatory function. The highest degree of platelet activation was found directly after DHCA. Conclusions: A major benefit of ROTEM((R)) is the quick detection of a developing coagulopathy already during CPB. ROTEM((R)) guides quick and specific blood product treatment after CPB, which may decrease bleeding complications in cardiac surgery. The finding of maximal platelet activation directly after DHCA suggests that not only CPB but also hypothermia activates platelets in vivo, thereby contributing to platelet dysfunction. 相似文献
99.
Aurora M. Morariu Theo A. Schuurs Henri G. D. Leuvenink Wim van Oeveren Gerhard Rakhorst Rutger J. Ploeg 《American journal of transplantation》2008,8(5):933-941
Cerebral injury leading to brain death (BD) causes major physiologic derangements in potential organ donors, which may result in vascular-endothelial activation and affect posttransplant graft function. We investigated the kinetic of pro-coagulatory and pro-inflammatory endothelial activation and the subsequent oxidative stress and renal tubular injury, early after BD declaration. BD was induced by slowly inflating a balloon-catheter inserted in the extradural space over a period of 30 min. Rats (n = 30) were sacrificed 0.5, 1, 2 or 4 h after BD-induction and compared with sham-controls. This study demonstrates immediate pro-coagulatory and pro-inflammatory activation of vascular endothelium after BD in kidney donor rats, proportional with the duration of BD. E- and P-Selectins, Aα/Bβ-fibrinogen mRNA were abruptly and progressively up-regulated from 0.5 h BD onwards; P-Selectin membrane protein expression was increased; fibrinogen was primarily visualized in the peritubular capillaries. Plasma von Willebrand factor was significantly higher after 2 h and 4 h BD. Urine heart-fatty-acid-binding-protein and N-acetyl-glucosaminidase, used as new specific and sensitive markers of proximal and distal tubular damage, were found significantly increased after 0.5 h, with a maximum at 4 h. Unexpectedly, oxidative stress was detectable only late, after the installation of tubular injury, suggesting only a secondary role for hypoxia in triggering these injuries. 相似文献
100.