全文获取类型
收费全文 | 756篇 |
免费 | 40篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 53篇 |
妇产科学 | 8篇 |
基础医学 | 65篇 |
口腔科学 | 17篇 |
临床医学 | 92篇 |
内科学 | 165篇 |
皮肤病学 | 7篇 |
神经病学 | 17篇 |
特种医学 | 162篇 |
外科学 | 37篇 |
综合类 | 12篇 |
预防医学 | 20篇 |
眼科学 | 95篇 |
药学 | 45篇 |
肿瘤学 | 35篇 |
出版年
2024年 | 2篇 |
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 15篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 18篇 |
2012年 | 15篇 |
2011年 | 22篇 |
2010年 | 44篇 |
2009年 | 40篇 |
2008年 | 22篇 |
2007年 | 39篇 |
2006年 | 19篇 |
2005年 | 19篇 |
2004年 | 15篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 21篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 48篇 |
1997年 | 47篇 |
1996年 | 45篇 |
1995年 | 40篇 |
1994年 | 42篇 |
1993年 | 26篇 |
1992年 | 3篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 28篇 |
1988年 | 23篇 |
1987年 | 12篇 |
1986年 | 15篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1969年 | 1篇 |
排序方式: 共有833条查询结果,搜索用时 15 毫秒
171.
Alexandre Mebazaa Antonis A Pitsis Alain Rudiger Wolfgang Toller Dan Longrois Sven-Erik Ricksten Ilona Bobek Stefan De Hert Georg Wieselthaler Uwe Schirmer Ludwig K von Segesser Michael Sander Don Poldermans Marco Ranucci Peter CJ Karpati Patrick Wouters Manfred Seeberger Edith R Schmid Walter Weder Ferenc Follath 《Critical care (London, England)》2010,14(2):1-14
Acute cardiovascular dysfunction occurs perioperatively in more than 20% of cardiosurgical patients, yet current acute heart failure (HF) classification is not applicable to this period. Indicators of major perioperative risk include unstable coronary syndromes, decompensated HF, significant arrhythmias and valvular disease. Clinical risk factors include history of heart disease, compensated HF, cerebrovascular disease, presence of diabetes mellitus, renal insufficiency and high-risk surgery. EuroSCORE reliably predicts perioperative cardiovascular alteration in patients aged less than 80 years. Preoperative B-type natriuretic peptide level is an additional risk stratification factor. Aggressively preserving heart function during cardiosurgery is a major goal. Volatile anaesthetics and levosimendan seem to be promising cardioprotective agents, but large trials are still needed to assess the best cardioprotective agent(s) and optimal protocol(s). The aim of monitoring is early detection and assessment of mechanisms of perioperative cardiovascular dysfunction. Ideally, volume status should be assessed by 'dynamic' measurement of haemodynamic parameters. Assess heart function first by echocardiography, then using a pulmonary artery catheter (especially in right heart dysfunction). If volaemia and heart function are in the normal range, cardiovascular dysfunction is very likely related to vascular dysfunction. In treating myocardial dysfunction, consider the following options, either alone or in combination: low-to-moderate doses of dobutamine and epinephrine, milrinone or levosimendan. In vasoplegia-induced hypotension, use norepinephrine to maintain adequate perfusion pressure. Exclude hypovolaemia in patients under vasopressors, through repeated volume assessments. Optimal perioperative use of inotropes/vasopressors in cardiosurgery remains controversial, and further large multinational studies are needed. Cardiosurgical perioperative classification of cardiac impairment should be based on time of occurrence (precardiotomy, failure to wean, postcardiotomy) and haemodynamic severity of the patient's condition (crash and burn, deteriorating fast, stable but inotrope dependent). In heart dysfunction with suspected coronary hypoperfusion, an intra-aortic balloon pump is highly recommended. A ventricular assist device should be considered before end organ dysfunction becomes evident. Extra-corporeal membrane oxygenation is an elegant solution as a bridge to recovery and/or decision making. This paper offers practical recommendations for management of perioperative HF in cardiosurgery based on European experts' opinion. It also emphasizes the need for large surveys and studies to assess the optimal way to manage perioperative HF in cardiac surgery. 相似文献
172.
173.
P Abbey CJ Das GS Pangtey A Seith R Dutta A Kumar 《Journal of Medical Imaging and Radiation Oncology》2009,53(1):22-31
Bronchopulmonary sequestration is an uncommon pulmonary disorder characterized by an area of non‐functioning abnormal lung tissue, which receives its blood supply from a systemic artery and characteristically has no connection with the tracheobronchial tree. The abnormal lung tissue is located within the visceral pleura of a pulmonary lobe in the intralobar variety, whereas the extralobar form has its own visceral pleura. The venous drainage of the extralobar type is usually into the systemic veins, whereas the intralobar type drains into the pulmonary veins. Radiological imaging plays a vital role in establishing the diagnosis, and even more importantly, in providing to the clinician a vascular roadmap essential for surgical planning. We present here a review of bronchopulmonary sequestration and also discuss the role of various imaging methods in the early diagnosis and management of these cases. 相似文献
174.
175.
Hua Li Shih-Wen Lin Wynetta Giles-Davis Yan Li Dongming Zhou Zhi Quan Xiang Katherine A High Hildegund CJ Ertl 《Molecular therapy》2009,17(7):1215-1224
Hepatic adeno-associated virus (AAV)-serotype 2–mediated gene transfer results in sustained transgene expression in experimental animals but not in human subjects. We hypothesized that loss of transgene expression in humans might be caused by immune memory mechanisms that become reactivated upon AAV vector transfer. Here, we tested the effect of immunological memory to AAV capsid on AAV-mediated gene transfer in a mouse model. Upon hepatic transfer of an AAV2 vector expressing human factor IX (hF.IX), mice immunized with adenovirus (Ad) vectors expressing AAV8 capsid before AAV2 transfer developed less circulating hF.IX and showed a gradual loss of hF.IX gene copies in liver cells as compared to control animals. This was not observed in mice immunized with an Ad vectors expressing AAV2 capsid before transfer of rAAV8-hF.IX vectors. The lower hF.IX expression was primarily linked to AAV-binding antibodies that lacked AAV-neutralizing activity in vitro rather than to AAV capsid–specific CD8+ T cells. 相似文献
176.
177.
Park JY Takahara N Gabriele A Chou E Naruse K Suzuma K Yamauchi T Ha SW Meier M Rhodes CJ King GL. 《Journal of the peripheral nervous system : JPNS》2001,6(1):60-61
Enhanced actions or levels of endothelin-1 (ET-1), a potent vasoconstrictor, have been associated with decreased blood flow in the retina and peripheral nerves of diabetic animals and may be related to the development of pathologies in these tissues. Hyperglycemia has been postulated to increase ET-1 secretion in endothelial cells. We have characterized the mechanism by which elevation of glucose is increasing ET-1 mRNA expression in capillary bovine retinal endothelial cells (BREC) and bovine retinal pericytes (BRPC). Elevation of glucose, but not mannitol, from 5.5 to 25 mmol/l for 3 days increased membranous protein kinase C (PKC) activities and ET-1 mRNA in parallel levels by 2-fold in BREC and BRPC. These effects were reversed by decreasing glucose levels to 5.5 mmol/l for an additional 2 days. Glucose-induced ET-1 overexpression was inhibited by a general PKC inhibitor, GF109203X, and a mitogen-activated protein kinase kinase inhibitor, PD98059, but not by wortmannin, a phosphatidylinositol 3-kinase inhibitor. By immunoblot analysis, PKC-beta 2 and -delta isoforms in BREC were significantly increased relative to other isoforms in the membranous fractions when glucose level was increased. Overexpression of PKC-beta 1 and -delta isoforms but not PKC-zeta isoform by adenovirus vectors containing the respective cDNA enhanced in parallel PKC activities, proteins, and basal and glucose-induced ET-1 mRNA expression by at least 2-fold. These results showed that enhanced ET-1 expression induced by hyperglycemia in diabetes is partly due to activation of PKC-beta and -delta isoforms, suggesting that inhibition of these PKC isoforms may prevent early changes in diabetic retinopathy and neuropathy. 相似文献
178.
KI Wheeler GM Schmölzer CJ Morley PG Davis 《Acta paediatrica (Oslo, Norway : 1992)》2011,100(1):67-70
Background: Ventilator frequency is one of the determinants of tidal volume delivery during high‐frequency ventilation. Clinicians increasingly use data on ventilator displays to inform their decisions. Aim: To measure the frequencies delivered by the Dräger Babylog 8000plus ventilator when used in high‐frequency mode. Methods: Ventilator waveforms using a test lung were recorded at the full range of settings 5–20 Hz using Spectra software at 1000 Hz. The changes in frequency produced by a 1‐ Hz change in set frequency were calculated. Actual and displayed frequencies were compared. Results: For settings up to 12 Hz, median (range) difference between set and delivered frequencies was 0 (?0.4 to +0.1) Hz. Above 12 Hz, delivered frequency varied by ?0.3 (?1.9 to +0.3) Hz. For 1‐ Hz changes in frequency settings, in the range 5–12 Hz, 1‐ Hz changes produced a change in delivered frequency of 1.0 (0.6–1.4) Hz. Above 12 Hz, the corresponding changes were 0.7 (0–2.9) Hz. The ventilator displays the set frequency during operation rather than the delivered frequency. Conclusion: At 12 Hz and below, the differences between set and delivered frequencies were relatively small compared with those at 13 Hz and higher. Above 13 Hz, the difference between set and delivered frequencies was up to 2.9 Hz. Some frequency setting changes did not result in a change in delivered frequency. 相似文献
179.
CJ Stewart ECL Marrs S Magorrian A Nelson C Lanyon JD Perry ND Embleton SP Cummings JE Berrington 《Acta paediatrica (Oslo, Norway : 1992)》2012,101(11):1121-1127
Aim: To describe gut colonization in preterm infants using standard culture and 16S gene rRNA profiling, exploring differences in healthy infants and those who developed NEC/late onset sepsis (LOS). Methods: Ninety‐nine stools from 38 infants of median 27‐week gestation were cultured; 44 stools from 27 infants had their microbial profiles determined by 16S. Ordination analyses explored effects of patient variables on gut communities. Results: Standard microbiological culture identified a mean of two organisms (range 0–7), DGGE 12 (range 3–18) per patient. Enterococcus faecalis and coagulase negative staphylococci (CONS) were most common by culture (40% and 39% of specimens). Meconium was not sterile. No fungi were cultured. Bacterial community structures in infants with NEC and LOS differed from healthy infants. Infants who developed NEC carried more CONS (45% vs 30%) and less Enterococcus faecalis (31% vs 57%). 16S identified Enterobacter and Staphylococcus presence associated with NEC/LOS, respectively. Conclusions: Important differences were found in the gut microbiota of preterm infants who develop NEC/LOS. The relationship of these changes to current practices in neonatal intensive care requires further exploration. 相似文献
180.
Interleukin-5 is at 5q31 and is deleted in the 5q- syndrome 总被引:3,自引:0,他引:3
Sutherland GR; Baker E; Callen DF; Campbell HD; Young IG; Sanderson CJ; Garson OM; Lopez AF; Vadas MA 《Blood》1988,71(4):1150-1152
Human interleukin-5 (IL-5) is a selective eosinophilopoietic and eosinophil-activating growth hormone. By in situ hybridization this gene is mapped to chromosome 5q23.3 to 5q32. It is shown to be deleted in two patients with the 5q-syndrome and in one patient previously diagnosed with myelodysplasia whose condition had progressed to acute myeloblastic leukemia. The clustering of other genes involved in hematopoiesis (IL-3, granulocyte-macrophage colony-stimulating factor, feline sarcoma viral oncogene homolog, colony-stimulating factor 1) to the same region as IL-5 suggests a nonrandom localization and raises interesting questions concerning the evolution and regulation of these genes. 相似文献