全文获取类型
收费全文 | 12576篇 |
免费 | 955篇 |
国内免费 | 232篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 513篇 |
妇产科学 | 372篇 |
基础医学 | 1225篇 |
口腔科学 | 56篇 |
临床医学 | 2892篇 |
内科学 | 2578篇 |
皮肤病学 | 50篇 |
神经病学 | 236篇 |
特种医学 | 443篇 |
外科学 | 1538篇 |
综合类 | 1548篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 750篇 |
眼科学 | 81篇 |
药学 | 1086篇 |
7篇 | |
中国医学 | 144篇 |
肿瘤学 | 207篇 |
出版年
2024年 | 17篇 |
2023年 | 285篇 |
2022年 | 206篇 |
2021年 | 582篇 |
2020年 | 471篇 |
2019年 | 453篇 |
2018年 | 421篇 |
2017年 | 489篇 |
2016年 | 429篇 |
2015年 | 478篇 |
2014年 | 775篇 |
2013年 | 821篇 |
2012年 | 616篇 |
2011年 | 704篇 |
2010年 | 540篇 |
2009年 | 576篇 |
2008年 | 556篇 |
2007年 | 586篇 |
2006年 | 460篇 |
2005年 | 479篇 |
2004年 | 399篇 |
2003年 | 351篇 |
2002年 | 314篇 |
2001年 | 302篇 |
2000年 | 250篇 |
1999年 | 208篇 |
1998年 | 201篇 |
1997年 | 168篇 |
1996年 | 158篇 |
1995年 | 146篇 |
1994年 | 143篇 |
1993年 | 116篇 |
1992年 | 125篇 |
1991年 | 100篇 |
1990年 | 74篇 |
1989年 | 101篇 |
1988年 | 83篇 |
1987年 | 63篇 |
1986年 | 57篇 |
1985年 | 73篇 |
1984年 | 74篇 |
1983年 | 46篇 |
1982年 | 67篇 |
1981年 | 52篇 |
1980年 | 33篇 |
1979年 | 21篇 |
1978年 | 17篇 |
1977年 | 15篇 |
1976年 | 16篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion. 相似文献
3.
Aaron Pitzele Mohammad Rahimi Eric Armbrecht 《The journal of maternal-fetal & neonatal medicine》2015,28(15):1770-1773
Objective: To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.Design/Methods: VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3?h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45?min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15?ml/kg of PRBC transfusion was given over 3?h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48?h after the transfusion.Results: Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48?h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.Conclusions: PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24?h post-transfusion. 相似文献
4.
Anuj Shrestha Zeeshan Jawa Kathryn L. Koch Amy B. Rankin Qun Xiang Anand Padmanabhan Matthew S. Karafin Joshua J. Field 《Journal of clinical apheresis》2015,30(6):353-358
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
5.
6.
7.
Lorena Martin-Morales Sara Manzano Maria Rodrigo-Faus Adrian Vicente-Barrueco Victor Lorca Gonzalo Núñez-Moreno Paloma Bragado Almudena Porras Trinidad Caldes Pilar Garre Alvaro Gutierrez-Uzquiza 《International journal of cancer. Journal international du cancer》2023,152(2):283-297
Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and nonmatrix proteins. Although most MMPs are secreted as inactive proenzymes and are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11's protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future. 相似文献
8.
Bernard Natukunda Grace Ndeezi Lay See Er Francis Bajunirwe Gayle Teramura Meghan Delaney 《ISBT科学丛刊》2019,14(4):366-373
9.
10.
《Burns : journal of the International Society for Burn Injuries》2021,47(5):1038-1044
IntroductionAlthough blood transfusion is common in burns, data are lacking in appropriate transfusion thresholds. It has been reported that a restrictive blood transfusion policy decreases blood utilization and improves outcomes in critically ill adults, but the impact of a restrictive blood transfusion policy in burn patients is unclear. We decided to investigate the outcome of decreasing the blood transfusion threshold.Material and methodsEighty patients with TBSA > 20% who met our inclusion criteria were included. They were randomly divided into control and intervention groups. The intervention group received packed cells only when Hemoglobin declined to less than 8 g/dL at routine laboratory evaluations. While the control group received packed-cell when hemoglobin was declined to less than 10 g/dl. The total number of the received packed cell before, during and after any surgical procedure was recorded. The outcome was measured by the evaluation of the infection rate and other complications.ResultThe mean hemoglobin level before transfusion was 7.7 ± 0.4 g/dL in the restrictive group and 8.8 ± 0.7 g/dL in the liberal group. The mean number of RBC unit transfusion per patient in the restrictive group was significantly lower than the traditional group (3.28 ± 2.2 units vs. 5.9 ± 3.7 units) (p-value = 0.006). The total number of RBC transfused units varied significantly between the two groups (p-value = 0.014). The number of transfused RBC units outside the operation room showed a significant difference between groups (restrictive: 2.8 ± 1.4 units vs. liberal: 4.4 ± 2.6 units) (p = 0.004). We did not find any significant difference in mortality rate or other outcome measures between groups.ConclusionApplying the restrictive transfusion strategy in thermal burn patients who are highly prone to all kinds of infection, does not adversely impact the patient outcome, and results in significant cost savings to the institution and lower rate of infection. We conclude that the restrictive transfusion practice during burn excision and grafting is well tolerated and effective in reducing the number of transfusions without increasing complications.Clinical Trial Registration ReferenceIRCT20190209042660N1. 相似文献