首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1788篇
  免费   115篇
  国内免费   4篇
耳鼻咽喉   23篇
儿科学   37篇
妇产科学   43篇
基础医学   253篇
口腔科学   22篇
临床医学   173篇
内科学   347篇
皮肤病学   38篇
神经病学   183篇
特种医学   41篇
外科学   229篇
综合类   5篇
一般理论   2篇
预防医学   193篇
眼科学   96篇
药学   89篇
中国医学   3篇
肿瘤学   130篇
  2023年   24篇
  2022年   28篇
  2021年   51篇
  2020年   51篇
  2019年   54篇
  2018年   52篇
  2017年   32篇
  2016年   42篇
  2015年   56篇
  2014年   70篇
  2013年   99篇
  2012年   132篇
  2011年   134篇
  2010年   63篇
  2009年   47篇
  2008年   98篇
  2007年   105篇
  2006年   109篇
  2005年   75篇
  2004年   86篇
  2003年   62篇
  2002年   65篇
  2001年   41篇
  2000年   31篇
  1999年   29篇
  1998年   16篇
  1997年   13篇
  1996年   11篇
  1995年   8篇
  1994年   10篇
  1993年   9篇
  1992年   26篇
  1991年   13篇
  1990年   18篇
  1989年   18篇
  1988年   19篇
  1987年   9篇
  1986年   14篇
  1985年   20篇
  1984年   5篇
  1983年   6篇
  1982年   12篇
  1980年   4篇
  1978年   3篇
  1977年   8篇
  1972年   3篇
  1966年   2篇
  1946年   2篇
  1939年   2篇
  1933年   2篇
排序方式: 共有1907条查询结果,搜索用时 15 毫秒
1.
Marie Warrer Petersen  Tine Sylvest Meyhoff  Marie Helleberg  Maj-Brit Nørregaard Kjær  Anders Granholm  Carl Johan Steensen Hjortsø  Thomas Steen Jensen  Morten Hylander Møller  Peter Buhl Hjortrup  Mik Wetterslev  Gitte Kingo Vesterlund  Lene Russell  Vibeke Lind Jørgensen  Klaus Tjelle  Thomas Benfield  Charlotte Suppli Ulrik  Anne Sofie Andreasen  Thomas Mohr  Morten H. Bestle  Lone Musaeus Poulsen  Mette Friberg Hitz  Thomas Hildebrandt  Lene Surland Knudsen  Anders Møller  Christoffer Grant Sølling  Anne Craveiro Brøchner  Bodil Steen Rasmussen  Henrik Nielsen  Steffen Christensen  Thomas Strøm  Maria Cronhjort  Rebecka Rubenson Wahlin  Stephan Jakob  Luca Cioccari  Balasubramanian Venkatesh  Naomi Hammond  Vivekanand Jha  Sheila Nainan Myatra  Christian Gluud  Theis Lange  Anders Perner 《Acta anaesthesiologica Scandinavica》2020,64(9):1365-1375

Introduction

Severe acute respiratory syndrome coronavirus-2 has caused a pandemic of coronavirus disease (COVID-19) with many patients developing hypoxic respiratory failure. Corticosteroids reduce the time on mechanical ventilation, length of stay in the intensive care unit and potentially also mortality in similar patient populations. However, corticosteroids have undesirable effects, including longer time to viral clearance. Clinical equipoise on the use of corticosteroids for COVID-19 exists.

Methods

The COVID STEROID trial is an international, randomised, stratified, blinded clinical trial. We will allocate 1000 adult patients with COVID-19 receiving ≥10 L/min of oxygen or on mechanical ventilation to intravenous hydrocortisone 200 mg daily vs placebo (0.9% saline) for 7 days. The primary outcome is days alive without life support (ie mechanical ventilation, circulatory support, and renal replacement therapy) at day 28. Secondary outcomes are serious adverse reactions at day 14; days alive without life support at day 90; days alive and out of hospital at day 90; all-cause mortality at day 28, day 90, and 1 year; and health-related quality of life at 1 year. We will conduct the statistical analyses according to this protocol, including interim analyses for every 250 patients followed for 28 days. The primary outcome will be compared using the Kryger Jensen and Lange test in the intention to treat population and reported as differences in means and medians with 95% confidence intervals.

Discussion

The COVID STEROID trial will provide important evidence to guide the use of corticosteroids in COVID-19 and severe hypoxia.
  相似文献   
2.
To investigate the phenotypic consequences of a deranged lymphangiogenesis in relation to tissue fluid accumulation and the possible role of inflammation in the pathogenesis of lymphoedema, we measured determinants of transcapillary fluid filtration and inflammatory mediators in the interstitial fluid in genetically engineered Chy mice, a model for primary congenital lymphoedema (Milroy's disease). Although initial lymphatics were not present in dermis in any of the areas studied (fore paw, hind paw, thigh and back skin) interstitial fluid pressure ( P if), measured with micropipettes, and tissue fluid volumes were significantly increased only in the areas with visible swelling – the fore and hind paw, whereas interstitial colloid osmotic pressure (COPif) was increased in all the skin areas examined. A volume load of 15% of body weight resulted in a more pronounced increase in P if as well as a four-fold increase in interstitial fluid volume in Chy relative to wild-type (wt) mice, showing the quantitative importance of lymphatics for fluid homeostasis during acute perturbations. A similar level of proinflammatory markers in interstitial fluid in early established lymphoedema (3–4 months) in Chy and wt suggests that inflammation does not have a major pathogenetic role for the development of lymphoedema, whereas a reduced level of the immunomodulatory cytokine interleukin (IL)-4 may result in a reduced immunological defence ability and thus lead to the increase in inflammatory cytokines IL-2 and IL-6 observed at a later stage (11–13 months). Our data suggest that primary lymphoedema results in a high interstitial fluid protein concentration that does not induce an interstitial inflammatory reaction per se , and furthermore shows the paramount importance of the initial lymphatics in tissue fluid homeostasis, especially during perturbations of transcapillary fluid balance.  相似文献   
3.
In premature neonates a patent ductus arteriosus causes often other complications thus the immediate closure of the patent ductus arteriosus should be preferred or recommended. Performing the surgical closure of the ductus within the incubator can avoid complications during transportation from the premature neonates intensive care unit to the operating room. 25 very small premature neonates or those with another burden in addition were operated upon in the incubator on the premature infants intensive care unit of our hospital during the period from January 1987 to April 1989. No complications occurred during the operation, especially not caused by the strange circumstances for the operating team. Wound infections because of possible bacterial contamination of the incubator or the room were not observed during the postoperative period.  相似文献   
4.
In six patients with doxorubicin-related cardiotoxicity, the severity of decrease in left ventricle ejection fraction (LVEF) was associated with faster myocardial I-123 MIBG washout rates. In four patients with severely decreased LVEF (range 19% to 28%), the 4-hour washout rate varied from 43% to 56%. In two patients with moderate cardiotoxicity (LVEF 42% and 43%), the washout rates were 37% and 35%, respectively. In contrast, in another patient thought to have initial left ventricular dysfunction (LVEF dropped from 66% to 54%), the myocardial I-123 MIBG retention rate was not reduced (6% washout). Subsequent continuation of chemotherapy in this patient was without complication. Reduced I-123 MIBG uptake in the left ventricle generally correlated with areas with abnormal Fourier amplitude values, but in one of the patients with moderate cardiotoxicity, the I-123 MIBG uptake was not reduced in a region with loss of amplitude, indicating dysfunction but probably no myocardial denervation. Analysis of the regional myocardial retention in patients with cardiotoxicity showed no significant difference in the I-123 MIBG washout rates of both segments with or without loss of amplitude. These data suggest that in spite of a localized loss of ventricular function demonstrated by radionuclide angiocardiography, doxorubicin-related cardiotoxicity appears to be based on a global process of myocardial adrenergic derangement.  相似文献   
5.
Micro-Raman line broadening in synthetic carbonated hydroxyapatite   总被引:2,自引:0,他引:2  
Using a Raman microspectrometer, we have recorded Raman spectra of synthetically produced hydroxyapatite samples with varying carbonate contents. The apatites were produced from aqueous solutions at about 40 degrees C. From line-broadening values of the symmetric phosphate stretch, it was concluded that the carbonate substitution in these lattices has a maximum of 4.5 wt %. Both phosphate and hydroxyl ions seem to be involved in the carbonate substitution process.  相似文献   
6.
The present study examined the false negative error rate associated with the optional use of the Retention trial the Test of Memory Malingering (TOMM). TOMM scores from 150 traumatic brain injury and 150 chronic pain patients were examined. Results indicated that early termination of the TOMM resulted in 3% of patients going undetected by the TOMM. The practical cost of this error was minimized by the inclusion of at least one other SVT. Clinical implications are discussed.  相似文献   
7.
BACKGROUND: Glucose is an accepted osmotic agent for peritoneal dialysis (PD) although it has several drawbacks. Some of these drawbacks have been addressed by the introduction of solutions with low glucose degradation products and physiological pH in dual-chambered bags. Despite this achievement, there is a need for alternative osmotic agents.This randomized clinical trial analyzes 3-month's clinical experience with a mixture of 0.6% amino acids and 1.4% glycerol. METHODS: The study was performed at the renal units of the University Hospitals Ghent, Belgium, and Utrecht, The Netherlands. Stable PD patients were randomized for either protocol A (test solution, n = 5) or protocol B (control regimen, n = 5). In both protocols, there was a run-in phase of 1 month with a dialysis regimen of 2 x 2 L 2.27% glucose solution (Dianeal; Baxter, Nivelles, Belgium), 1 x 2 L Extraneal (Baxter), and 1 x 2 L glucose solution (Dianeal). After this month-long run-in period, patients in group A received during 3 months 2 x 2 L amino acid/glycerol solution, 1 x 2 L Extraneal, and at least 1 x 2 L of a classic glucose solution. RESULTS: Glucose absorption decreased in the test group during the test phase (from 84.2 +/- 8.7 to 11.7 +/- 11.6 g/24 hours, p = 0.001). Dialysate levels of cancer antigen 125 (CA125) increased in the test group, from 17.5 +/- 11.0 to 32.4 +/- 4.6 units/L (p = 0.04), whereas, in the control group, the levels remained stable (15.5 +/- 8.7 and 14.9 +/- 9.8 units/L respectively, p = 0.4).There were no differences in serum urea, serum bicarbonate, serum osmolarity, serum albumin, or parameters related to skin-fold thickness or serum glycerol levels between control and test solutions. No differences were observed in obtained ultrafiltration after a 4-hour dwell with 2.27% glucose or the test solution, both measured at week 4 of the run-in period and week 12 of the test period. CONCLUSION: This study demonstrated that the use of a new 0.6% amino acid/1.4% glycerol-containing dialysis solution is safe and well tolerated. Glucose load was reduced significantly and dialysate CA125 levels improved significantly. Ultrafiltration was comparable with that of a 2.27% glucose solution. All these factors, in combination with the potential nutritional benefits, can contribute to a beneficial impact on the success of the PD technique. Further long-term studies in larger patient groups are warranted to explore the potential of this promising new solution.  相似文献   
8.
9.
Summary We have studied the histogenesis of malignant lymphoma (ML), small cleaved cell of the B-cell type and intermediate lymphocytic lymphoma (mantle zone lymphoma) by comparing immunophenotypes and ALP-activity of neoplastic cells with those of germinal center cells (follicular center cells) anti mantle zone (MZ) cells of secondary follicles in non-neoplastic lymphoid tissues. The neoplastic cells in 3 cases of ML, follicular, small cleaved cell and 1 case of ML, small cleaved cell expressed the phenotypes similar to those of germinal center (GC) B lymphocytes (SIgM+, B1+, B2+, CALLA+, SigD, IL-2R, Leu-1 and ALP). The neoplastic cells in 2 cases of ML, follicular, small cleaved cell and 12 cases of ML, diffuse, small cleaved cell displayed the characteristic phenotypes of MZ B lymphocytes (SIgM+, SIgD+, BA-1+, IL-2R+, Leu-1+ and ALP+). The phenotypes of 2 cases of mantle zone lymphoma were closely comparable with those of MZ B lymphocytes. These findings indicate that the histogenesis of ML, small cleaved cell of the B-cell type is heterogeneous and can be divided phenotypically into 2 types (GC B lymphocyte origin and MZ B lymphocyte origin). It is also apparent that intermediate lymphocytic lymphoma (mantle zone lymphoma) is derived from MZ B lymphocytes of secondary follicles.This work was supported by a Grant-in-Aid for Cancer Research From the Ministry of Health and Welfare (NO. 61-2)  相似文献   
10.
Nonobese diabetic (NOD) mice develop multi-organ autoimmune diseases, including type 1 diabetes. We hypothesized that backcrossing the MHC region from SJL (H-2(s)) mice, which have an endogenous PLP(139-151)-reactive repertoire, onto the background of autoimmune-prone NOD mice would result in a mouse strain that is highly susceptible to experimental autoimmune encephalomyelitis (EAE). Unexpectedly, although we detected an endogenous PLP(139-151) repertoire in the NOD.S mice, they did not develop spontaneous EAE and were relatively resistant to PLP(139-151)-induced EAE when compared to SJL mice. This resistance was associated with lower production of proinflammatory cytokines and a decreased expansion of PLP(139-151)-specific CD4(+) T cells after immunization and restimulation with PLP peptide in vitro. V(beta) chain usage among PLP(139-151)-reactive T cells differed between SJL and NOD.S mice. Furthermore, NOD.S mice were resistant to the development of insulitis and cyclophosphamide-induced diabetes, but not sialadenitis. Altogether, even though NOD mice develop spontaneous autoimmune diseases, they become relatively resistant to induction of EAE even when they express the EAE-permissive class II molecule I-A(s). Our data show that certain combinations of otherwise susceptibility-conferring MHC and non-MHC genes can mediate autoimmune-disease resistance when they are paired together. These findings do not support the "shared autoimmune gene" hypothesis.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号