全文获取类型
收费全文 | 6750篇 |
免费 | 350篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 50篇 |
儿科学 | 110篇 |
妇产科学 | 116篇 |
基础医学 | 966篇 |
口腔科学 | 103篇 |
临床医学 | 609篇 |
内科学 | 1180篇 |
皮肤病学 | 351篇 |
神经病学 | 755篇 |
特种医学 | 359篇 |
外科学 | 903篇 |
综合类 | 54篇 |
预防医学 | 326篇 |
眼科学 | 120篇 |
药学 | 510篇 |
中国医学 | 29篇 |
肿瘤学 | 591篇 |
出版年
2023年 | 38篇 |
2022年 | 74篇 |
2021年 | 120篇 |
2020年 | 83篇 |
2019年 | 97篇 |
2018年 | 133篇 |
2017年 | 130篇 |
2016年 | 159篇 |
2015年 | 208篇 |
2014年 | 239篇 |
2013年 | 278篇 |
2012年 | 444篇 |
2011年 | 440篇 |
2010年 | 306篇 |
2009年 | 283篇 |
2008年 | 471篇 |
2007年 | 494篇 |
2006年 | 491篇 |
2005年 | 475篇 |
2004年 | 418篇 |
2003年 | 426篇 |
2002年 | 431篇 |
2001年 | 89篇 |
2000年 | 59篇 |
1999年 | 92篇 |
1998年 | 102篇 |
1997年 | 78篇 |
1996年 | 66篇 |
1995年 | 41篇 |
1994年 | 48篇 |
1993年 | 41篇 |
1992年 | 30篇 |
1991年 | 11篇 |
1990年 | 17篇 |
1989年 | 18篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 19篇 |
1979年 | 7篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1975年 | 7篇 |
1973年 | 7篇 |
排序方式: 共有7132条查询结果,搜索用时 15 毫秒
61.
62.
Oliver Klass Uwe M. Fischer Albert Antonyan Mafalda Bosse Juergen H. Fischer Wilhelm Bloch 《Journal of investigative surgery》2013,26(6):349-356
Cardiopulmonary bypass (CPB) and cardioplegic arrest are associated with pulmonary dysfunction. We sought to investigate whether pulmonary ischemia/reperfusion during standard CPB and cardioplegic arrest is associated with reactive oxygen species (ROS)-mediated pulmonary tissue injury and pneumocyte apoptosis induction, and whether ROS scavenging using N-acetylcysteine (NAC) attenuates these alterations. Twelve pigs (41 ± 8 kg) were randomized to receive either NAC (100 mg/kg prior to CPB; n = 7) or placebo (n = 5) and subjected to CPB and 60 min of cold (4°C) crystalloid cardioplegic arrest. We collected lung biopsies prior to CPB, at 60 min CPB, as well as at 30, 60, and 120 min post CPB. Lung specimens were immunocytochemically stained against nitrotyrosine, 8-isoprostaglandin-F2α, and 8-hydroxy-2′-deoxyguanosine (8-OH-dG) as indicators for ROS-mediated tissue injury and active caspase-3, an apoptosis signal pathway key enzyme. Oxidative stress markers were judged using a scale from 1 to 4 (low to intensive staining), and caspase-3-positive pneumocytes were counted per view field. In placebo, the number of caspase-3-positive pneumocytes significantly increased over time to reach a maximum at 120 min post CPB (p =. 03 vs baseline). NAC significantly prevented caspase-3 activation in pneumocytes (p =. 001 vs Placebo). Pneumocyte nitrotyrosine and 8-OH-dG staining significantly increased over time (p =. 003) in the placebo group, but decreased in the NAC group (p =. 004). In both groups staining for 8-isoprostaglandin-F2α showed no significant changes. This yields the conclusion that standard CPB and cardioplegic arrest initiate ROS-mediated tissue injury and apoptosis in pneumocytes that can be reduced by NAC. Thus, ROS scavenging using NAC may represent a novel approach to minimize lung injury associated with CPB. 相似文献
63.
Comparison of three-dimensional rotational angiography with digital subtraction angiography in the assessment of ruptured cerebral aneurysms 总被引:21,自引:0,他引:21
BACKGROUND AND PURPOSE: Rotational angiography (RA) and digital subtraction angiography (DSA) together may depict more intracranial aneurysms than DSA alone. We compared the diagnostic value of 3D RA and biplanar DSA in detecting, classifying, and planning treatment for ruptured intracranial aneurysms. METHODS: A total of 53 patients with acute subarachnoid hemorrhage (Hunt and Hess grades I-V) underwent angiography with both methods. DSA was performed in two to six standard projections in every vascular territory. Three-dimensional RA datasets were evaluated by using surface-shaded display and maximum intensity projection. The usefulness of DSA images and 3D datasets in detecting aneurysms (number, configuration) and treatment planning were retrospectively analyzed in a blinded manner. RESULTS: In 42 patients, 56 aneurysms were detected, (one to five per patient; size, 0.6-20.4 mm); no aneurysm was found in 11 patients. RA revealed seven aneurysms not seen at conventional DSA. RA failed to depict one aneurysm visible only in a compression series. Delineation of the aneurysmal neck improved with RA in 71% of cases; the parent vessel and its relationship to adjacent vessels was demonstrated better with RA than with DSA in 45% and 50%, respectively. Endovascular treatment was proposed in nine patients; microsurgical therapy, in 26. In seven patients, both options were rated as being equal. Actual treatment consisted of eight endovascular procedures and 30 neurosurgical operations. Four patients died before therapy. CONCLUSION: Compared with DSA, 3D RA allows more exact depiction of anatomic details that are important in planning surgery and interventional therapy for intracranial aneurysms. RA depicted more aneurysms. 相似文献
64.
Theodor W. Kaulich Ulf Lamprecht Frank Paulsen Frank Kahmann Uwe Maurer Thomas Oliver Henkel Wolfgang Loeser Karl-Horst Bichler Fridtjof Nüsslin Michael Bamberg 《Strahlentherapie und Onkologie》2002,178(10):548-555
BACKGROUND: Interstitial brachytherapy with I-125 seeds can be used for successful treatment of early stage prostate cancer. There is presented the technique of permanent transperineal implantation of I-125 seeds with intraoperative treatment planning which is suited for the treatment of prostate cancer up to the clinical stage of T2a. MATERIAL AND METHODS: Some weeks before the implantation of the seeds the prostate volume is determined using transrectal ultrasound (TRUS) so as to estimate the required number of I-125 seeds. At the outset of the treatment the prostate is stabilized by two perineally inserted needles. Subsequently there is carried out an ultrasound guided treatment planning that allows to optimize the distribution of the seeds within the prostate. In interstitial brachytherapy we use RAPID STRANDS((R)), i. e. the I-125 seeds are embedded in vicryl suture at distances of 1 cm. During implantation of the I-125 seeds the transversal placement of the applicator needles is controlled by TRUS and the cranio-caudal placement of the applicator needles is controlled using the fluoroscopic unit as well as TRUS. About 4 weeks after the implantation of the seeds there is carried out a postoperative computation of the dose distribution of the implant using CT imaging. RESULTS: The procedure possesses the advantage that ultrasound imaging, treatment planning and seed implantation are carried out with the prostate remaining in an unaltered position. During implantation the combined imaging of TRUS and fluoroscopy allows a safe placement of the seeds with in the prostate. CONCLUSION: The methods for the calculation of the actually attained dose distribution must still be optimized, because the postoperative examination of the individual results has so far been possible only with difficulties resulting from methodological inconveniences. 相似文献
65.
Pretreatment with β‐adrenergic receptor agonists facilitates induction of LTP and sharp wave ripple complexes in rodent hippocampus 下载免费PDF全文
Rizwan ul Haq Marlene Anderson Agustin Liotta Maria Shafiq Muhammad Azhar Sherkheli Uwe Heinemann 《Hippocampus》2016,26(12):1486-1492
Norepinephrine, is involved in the enhancement of learning and memory formation by regulating synaptic mechanisms through its ability to activate pre‐ and post‐synaptic adrenergic receptors. Here we show that β‐agonists of norepinephrine facilitate the induction of both associational LTP and sharp wave ripples (SPW‐Rs) in acute slices of rat hippocampus in area CA3. Surprisingly, this facilitating effect persists when slices are only pretreated with β‐receptor agonists followed by wash out and application of the unspecific β‐adrenoreceptor (βAR) antagonist propranolol. During application of βAR agonists repeated stimulation resulted in facilitated induction of SPW‐Rs. Since SPW‐Rs are thought to be involved in memory replay we studied the effects of βAR‐agonists on spontaneous SPW‐Rs in murine hippocampus and found that amplitude and incidence of SPW‐Rs increased. These effects involve cyclic‐AMP and the activation of protein kinase A and suggest a supportive role in memory consolidation. © 2016 Wiley Periodicals, Inc. 相似文献
66.
Dr. med. Susanne Oertel Uwe Schneider Marius Keel Urs Martin Lütolf Georg Bosshard 《Strahlentherapie und Onkologie》2008,184(4):212-217
BACKGROUND AND PURPOSE: Heterotopic ossification (HO) often follows acetabular fractures after multitrauma. Irradiation is a mean for prophylaxis. We established a standard procedure in our hospital for patients under sedation, when obtaining informed consent for HO prophylaxis is impossible. PATIENTS AND METHODS: We reviewed current scientific evidence, calculated the risks of radiation and presented the ethical and legal framework. The subject was scrutinised by an interdisciplinary panel. RESULTS: Irradiation is the most effective means for prophylaxis and has few adverse effects in adult patients with fractures of the acetabulum. The lifetime risk of radiation-induced cancer or infertility are insignificant. CONCLUSIONS: Informed consent for irradiation should be obtained before operation whenever possible. When this cannot be done prophylaxis can be postponed for a maximum of 3 days in order to obtain consent. If the patient is not able to communicate within this period, prophylactic irradiation should be given after consulting the relatives. The patient must be informed as soon as possible. 相似文献
67.
Schick V Franzius C Beyna T Oei ML Schnekenburger J Weckesser M Domschke W Schober O Heindel W Pohle T Juergens KU 《European journal of nuclear medicine and molecular imaging》2008,35(10):1775-1785
Purpose This prospective single-centre phase II trial assessed the diagnostic impact of 18F-FDG PET–CT in the evaluation of solid pancreatic lesions (∅ ≥10 mm) compared to endosonography (EUS), endoscopic retrograde
cholangio-pancreatography (ERCP) with intraductal ultrasound (IDUS), abdominal ultrasound (US) and histopathological reference.
Methods Forty-six patients (32 men/14 women, ∅ 61.7 years) with suspected pancreatic neoplasms underwent PET–CT with contrast-enhanced
biphasic multi-detector CT of the upper abdomen followed by a diagnostic work-up with EUS, ERCP with IDUS and US within 3 weeks.
PET–CT data sets were analysed by two expert readers in a consensus reading. Histology from surgery, biopsy/fine-needle aspiration
and/or clinical follow-up ≥12 months served as standard of reference.
Results Twenty-seven pancreatic malignancies were histopathologically proven; 19 patients had benign diseases: 36/46 lesions (78%)
were detected in the head of the pancreas, 7/46 and 3/46 in the body and tail region, respectively. Sensitivity and specificity
of PET–CT were 89% and 74%, respectively; positive predictive value (PPV) and negative predictive value (NPV) were 83% and
82%, respectively. Sensitivity (81–89%), specificity (74–88%), PPV (83–90%) and NPV (77–82%) achieved by EUS, ERCP and US
were not significantly different. PET analysis revealed significantly higher maximum mean standardised uptake values (SUVmax 6.5 ± 4.6) in patients with pancreatic malignancy (benign lesions: SUVmax 4.2 ± 1.5; p < 0.05). PET–CT revealed cervical lymphonodal metastasis from occult bronchogenic carcinoma and a tubular colon adenoma with
intermediate dysplasia on polypectomy, respectively.
Conclusions
18F-FDG PET–CT achieves a comparably high diagnostic impact evaluating small solid pancreatic lesions versus conventional reference
imaging modalities. Additional clinical diagnoses are derived from concomitant whole-body PET–CT imaging.
Verena Schick and Christiane Franzius contributed equally to this work. 相似文献
68.
Tilmann Krackhardt Dankwart Höntzsch Uwe Ochs Kuno Weise 《Trauma und Berufskrankheit》2002,4(4):383-387
The small external fixator can be used in the treatment of injuries of the wrist and the distal forearm.This fixator is indicated especially when an unstable fracture needs to be treated, when the bone concerned is affected by osteoporosis in an elderly patient,and in the early treatment of polytraumatized patients with severe soft tissue injuries.For reduction of the fracture we prefer the modular three-tube technique, which is very gentle on the soft tissue; in addition we use the advantages of ligamentotaxis.Depending on the fracture type,we use the small external fixator alone or in association with an internal osteosynthesis.With scrupulous followup checks in the outpatient clinic loosening of the Schanz screws and infection around them are very rare. 相似文献
69.
Intrathecal and systemic concentration of NT-proBNP in patients with severe traumatic brain injury 总被引:2,自引:0,他引:2
Kirchhoff C Stegmaier J Bogner V Buhmann S Mussack T Kreimeier U Mutschler W Biberthaler P 《Journal of neurotrauma》2006,23(6):943-949
Outcome of patients suffering from traumatic brain injury (TBI) depends on the development of secondary brain damage. In this context, recent studies underlined the role of the natriuretic peptides- atrial natriuretic peptide and brain natriuretic peptide (BNP)-in aneurysmatic subarachnoidal hemorrhage (SAH). Especially BNP correlates with intracranial pressure and clinical outcome after SAH. Since its role in TBI remains unclear, the intracranial and systemic concentrations of N-terminal (NT)-proBNP were analyzed in patients suffering from severe TBI. We measured NT-proBNP levels in cerebrospinal fluid (CSF) and serum of 14 patients suffering from severe TBI (GCS15 mm Hg (n=6), the serum (800+/-150 pg/mL) and CSF levels (55+/-9 pg/mL) of NT-proBNP were significantly increased after 24 h, as compared to patients with ICP15 mm Hg. Further studies are currently performed to elucidate the physiologic role of NT-proBNP in TBI. 相似文献
70.
Philipp Mandel Felix Preisser Markus Graefen Thomas Steuber Georg Salomon Alexander Haese Uwe Michl Hartwig Huland Derya Tilki 《European urology》2017,71(6):848-850
Urinary incontinence (UI) and erectile dysfunction (ED) after radical prostatectomy (RP) can impose a strong burden. While most studies focus on certain time points after RP when analyzing functional outcome, there is paucity of evidence on late functional recovery in patients with UI or ED at 12 mo after RP. Using longitudinal patient data from a large European single-center, we show that the chance of regaining continence among patients (n = 974) with UI (≥1 pad/24 h) at 12 mo after RP was 38.6% after 24 mo and 49.7% after 36 mo. The corresponding rates for patients (n = 1115) with ED (defined as International Index of Erectile Function-5 score <18) at 12 mo after RP were 30.8% at 24 mo and 36.5% at 36 mo after RP. Patients with postoperative UI or ED 12 mo after RP should be counseled about their good chance of achieving continence or potency in the course of time.