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   14345篇
  免费   1835篇
  国内免费   282篇
耳鼻咽喉   76篇
儿科学   456篇
妇产科学   123篇
基础医学   839篇
口腔科学   265篇
临床医学   1079篇
内科学   2026篇
皮肤病学   207篇
神经病学   355篇
特种医学   1855篇
外国民族医学   9篇
外科学   923篇
综合类   1521篇
现状与发展   4篇
预防医学   1432篇
眼科学   94篇
药学   2784篇
  19篇
中国医学   349篇
肿瘤学   2046篇
  2024年   40篇
  2023年   281篇
  2022年   529篇
  2021年   709篇
  2020年   642篇
  2019年   588篇
  2018年   674篇
  2017年   598篇
  2016年   596篇
  2015年   526篇
  2014年   1109篇
  2013年   1192篇
  2012年   887篇
  2011年   937篇
  2010年   740篇
  2009年   675篇
  2008年   669篇
  2007年   618篇
  2006年   512篇
  2005年   431篇
  2004年   393篇
  2003年   326篇
  2002年   316篇
  2001年   265篇
  2000年   215篇
  1999年   222篇
  1998年   167篇
  1997年   165篇
  1996年   130篇
  1995年   151篇
  1994年   118篇
  1993年   106篇
  1992年   81篇
  1991年   91篇
  1990年   71篇
  1989年   88篇
  1988年   67篇
  1987年   61篇
  1986年   54篇
  1985年   82篇
  1984年   63篇
  1983年   38篇
  1982年   54篇
  1981年   43篇
  1980年   34篇
  1979年   33篇
  1978年   14篇
  1977年   23篇
  1976年   10篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Strict Closed-System Drainage for Treating Chronic Subdural Haematoma   总被引:4,自引:0,他引:4  
Summary. A comparative study chiefly of the recurrence rate of chronic subdural haematoma after two treatment modalities was conducted. Patients were divided into a burr hole strict closed-system drainage group (SCD group; n=56) and a burr hole closed-system drainage with irrigation group (CDI group; n=45). The burr hole strict closed-system drainage involved simply inserting a drainage tube into the haematoma cavity as quickly as possible after minimally incising the haematoma capsule. The introduction of air into the haematoma cavity was prevented, and irrigation was not performed. Symptoms in both groups disappeared soon after surgery, with no postoperative complications. Haematoma recurred in one patient (1.8%) of the SCD group compared with 5 (11.1%) of the CDI group. The rate of recurrence was significantly lower for the SCD than for the CDI group (p<0.05). In 4 of 5 recurrences in the CDI group, the volume of residual intracapsular air was sufficient after initial surgery. These results suggested that postoperative residual intracapsular air is a factor contributing to recurrence. Burr hole strict closed-system drainage is a simple, less invasive procedure with which to treat chronic subdural haematoma and the outcome is excellent. Furthermore, prevention of intracapsular air intrusion during surgery might help prevent recurrence.  相似文献   
92.
在辅助生殖助孕中通常采用控制性卵巢刺激(controlled ovarian hyperstimulation, COS),以获得适当数量的卵子用于体外受精,既希望获得理想的辅助生殖助孕成功率,又能降低卵巢过度刺激并发症.COS中约有9%~24%[1,2]的卵巢低反应发生率.卵巢低反应者获得有效卵子数少、可移植胚胎数少或无胚胎移植、取消治疗周期率高,累计成功率更低等,导致较差的治疗结局,是辅助生殖助孕中面临的棘手问题.针对卵巢低反应者,大多数辅助生殖中心仍会采用增加促性腺激素(Gn)的起始和(或)总用量以期获得提高助孕结局的目的.而大剂量Gn是否为改善低反应患者助孕结局的有效策略却仍存在争议.  相似文献   
93.
郭璇 《中国美容医学》2014,(22):1916-1918
目的:对两种桩核冠技术用于残根残冠修复的临床疗效进行对比。方法:将256例残根残冠患者(432颗前牙)随机分为对照组(n=216)与实验组(n=216,对照组患者采用金属铸造核桩技术进行治疗,实验组患者采用玻璃纤维桩树脂核技术进行治疗,每隔6个月对患者进行再次检测。结果:1年期成功率无显著性差异(P0.05),2年后成功率:对照组成功率86.1%,实验组成功率97.2%,有显著性差异(P0.05),实验组治疗效果要优于对照组。结论:对于前牙残根残冠的修复,玻璃纤维桩核冠技术的临床疗效要比金属铸造桩核冠技术更加安全、高效,值得临床推广应用。  相似文献   
94.
目的:研究5种不同形态牙本质肩领对牙根抗力的影响。方法:25颗完整离体上颌中切牙随机分成5组,按实验设计制备5种不同形态牙本质肩领:即360°环形肩领组、180°唇侧肩领组、180°腭侧肩领组、180°远中肩领组和无肩领组。所有离体牙均采用预成石英纤维桩、复合树脂核、镍铬合金全冠修复。试件于铸造全冠颈缘线下2mm包埋在自凝塑料中,电子万能试验机以与牙长轴成130°,加载速度为1.0mm/min,于样本牙腭面切端下2mm处加载,记录折裂载荷及牙体断裂的位置和方式,进行统计学分析。结果:5组样本牙抗折力值顺序为环形肩领组、腭侧肩领组远中肩领组唇侧肩领组无肩领组,前两组样本牙根抗折力显著高于后两组,差异有显著性(P0.01)。所有样本中可修复性折裂占92%。结论:残根龈上剩余牙本质的位置能影响桩核冠修复后的牙根抗力。  相似文献   
95.

Objectives

The purpose of this study was to determine the effective dose of radiation due to computed tomography (CT) scans in paediatric trauma patients at a level 1 Canadian paediatric trauma centre. We also explored the indications and actions taken as a result of these scans.

Patients and methods

We performed a retrospective review of paediatric trauma patients presenting to our centre from January 1, 2007 to December 31, 2008. All CT scans performed during the initial trauma resuscitation, hospital stay, and 6 months afterwards were included. Effective dose was calculated using the reported dose length product for each scan and conversion factors specific for body region and age of the patient.

Results

157 paediatric trauma patients were identified during the 2-year study period. Mean Injury Severity Score was 22.5 (range 12–75). 133 patients received at least one CT scan. The mean number of scans per patient was 2.6 (range 0–16). Most scans resulted in no further action (56%) or additional imaging (32%). A decision to perform a procedure (2%), surgery (8%), or withdrawal of life support (2%) was less common. The average dose per patient was 13.5 mSv, which is 4.5 times the background radiation compared to the general population. CT head was the most commonly performed type of scan and was most likely to be repeated. CT body, defined as a scan of the chest, abdomen, and/or pelvis, was associated with the highest effective dose.

Conclusions

CT is a significant source of radiation in paediatric trauma patients. Clinicians should carefully consider the indications for each scan, especially when performing non-resuscitation scans. There is a need for evidence-based treatment algorithms to assist clinicians in selecting appropriate imaging for patients with severe multisystem trauma.  相似文献   
96.
Racial differences among kidney transplant recipients may impact the total daily tacrolimus dose required to achieve therapeutic tacrolimus concentrations. Previous studies suggest that African Americans require higher doses to achieve similar therapeutic drug concentrations compared with Caucasians. Data were collected on a total of 147 de novo kidney transplant recipients. Tacrolimus total daily dose (TDD) requirements (mg/kg/d) and tacrolimus concentrations were retrospectively reviewed at discharge and at days 30, 60, and 90 after transplant. TDD requirements in African‐American and Caucasian patients were 0.14 mg/kg/d and 0.11 mg/kg/d, respectively (p = 0.005), at day 30. TDD requirements at day of hospital discharge and days 60 and 90 following transplant were significantly higher in African‐American patients vs. Caucasian patients, with similar tacrolimus concentrations at all time points. This study suggests that when compared to Caucasians, African Americans require significantly higher TDD of tacrolimus to achieve similar tacrolimus concentrations. These findings provide transplant clinicians with a sense of certainty to more rapidly titrate daily tacrolimus doses in African‐American patients to achieve therapeutic concentrations.  相似文献   
97.
Tacrolimus exposure and renal function data to 36 months post‐transplant were analyzed from the prospective, observational Mycophenolic acid Observational REnal transplant (MORE) registry in which de novo kidney transplant patients were managed according to local practice. Tacrolimus trough (C0) concentration at month 12 was stratified as low (<6 ng/mL), moderate (6–8 ng/mL), or high (>8 ng/mL) in 724 patients. Estimated glomerular filtration rate (eGFR) was stratified as low (<60 mL/min/1.73 m2) or high (≥60 mL/min/1.73 m2). High tacrolimus C0 (>8 ng/mL) was observed in 47.7%, 34.1%, 26.8%, and 26.7% of patients at baseline and months 12, 24, and 36, respectively. Biopsy‐proven acute rejection was similar to month 36 regardless of tacrolimus C0 category at month 12. Tacrolimus C0 >8 ng/mL vs. <6 ng/mL at month 12 was predictive of low eGFR at month 24 (p = 0.023) with a nonsignificant trend at month 36 (p = 0.085). Infections (p < 0.013) and BK virus infection (p < 0.001) were most frequent in the low tacrolimus C0 cohort. Neutropenia was most frequent in the high tacrolimus C0 category (p = 0.010). In conclusion, over a quarter of patients were exposed to high tacrolimus C0 to 36 months post‐transplant. Tacrolimus exposure did not affect rejection risk, but tacrolimus C0 >8 ng/mL at month 12 was predictive of subsequent low eGFR compared to C0 <6 ng/mL.  相似文献   
98.
There are limited data on total dose infusion (TDI) using iron dextran in geriatric chronic kidney disease (CKD) patients with iron-deficiency anemia (IDA). Our goal was to evaluate the safety of TDI in this setting. We conducted a retrospective chart review spanning a 5 year period (2002–2007), including all patients with CKD and IDA who were treated with iron dextran TDI. Patient demographics were noted, and laboratory values for creatinine, hemoglobin and iron stores were recorded pre- and post-dose. TDI diluted in normal saline was administered intravenously over 4-6 hours after an initial test dose. One hundred fifty-three patients received a total of 250 doses of TDI (mean?±?SD?=?971?±?175?mg); age was 69?±?12 years and creatinine 3.3?±?1.9?mg/dL. All stages of CKD were represented (stage 4 commonest). Hemoglobin and iron stores improved post-TDI (P?P?=?0.1433 by Fishers Exact Test). Iron dextran TDI is relatively safe and effective in correcting IDA in geriatric CKD patients. Fewer AEs were noted with the LMW compared to the HMW product. LMW iron dextran given as TDI can save both cost and time, helping to alleviate issues of non-compliance and patient scheduling.  相似文献   
99.
Optimal outcome for early breast cancer patients receiving adjuvant chemotherapy requires adequate dose delivery, commonly defined as >85% of planned dose of chemotherapy agents. Outside the clinical trial setting, reports from community oncology centres have demonstrated that a significant proportion of patients fail to receive this dose intensity, with neutropenia being the most commonly cited reason for sub-optimal treatment. Data collected prospectively on 1655 patient treated in a single breast cancer centre demonstrates that patients at risk of sub-optimal dose delivery can be identified by routine assessment of neutropenic events during the first cycle. The uniform administration of secondary G-CSF for all subsequent cycles enables dose delivery ≥85%, which was shown to lead to improved survival outcomes when compared with those patients who received <85%.  相似文献   
100.
ObjectivesRegional anaesthesia is considered the optimal technique for obstetric patients; nevertheless, the optimal method of regional anaesthesia for delivery remains to be determined. In our study we investigate the safety, efficacy and cost benefits of single-dose spinal analgesia in comparison with epidural analgesia during labour.Study designIn our study women in advanced labour were randomly allocated into two equal groups using a computer-generated randomization table, one group (spinal group = S group) were given 3.75 mg hyperbaric bupivacaine +25 μg fentanyl with 0.75 ml saline, the other group (Epidural group = E group) were given 4 ml bupivacaine with 4 ml saline and 1 ml (50 μg) fentanyl pain intensity was recorded by the parturient on a visual analogue scale. The quality of pain relief was also rated with a verbal score directly after delivery. Side effects, such as hypotension, Pruritus, sedation, nausea and motor block were noted. Obstetric parameters were followed and recorded, Apgar score were noted, and all the results were compared in the two groups.ResultsOnset of sensory block (detected by pin-prick test) was early (4.4 ± 1.5 min vs 12.5 ± 2.3 min, p < 0.001) and duration of sensory block was longer (120.4 ± 15.6 vs 103.2 ± 18.3 min, p < 0.001) in S group compared to E group, time to reach maximum dermatome level of sensory block (T10) was shorter in S than E group (8.3 ± 2.4 min vs 22.4 ± 5.7 min, p < 0.001), two segment regression occur late in S group compared to E group(75.6 ± 12.5 min vs 66.3 ± 9.4 min, p < 0.001). Visual analogue scores after 5, 15, 30, 60, 90, 120 and 150 min were lower in S group compared to E group, all the previous result is statically significant (p < 0.001). 88% of the parturients in S group vs 60% in E group scored the analgesic quality as excellent, the mean duration of analgesia (Mean ± SD) was longer in S group compared to E group. 8% of parturients in S group vs 14% of parturients in E group had hypotension. Motor block, sedation and nausea were 2–6% in both groups. Pruritus was seen in 60% in E group vs 25% in spinal one. No caesarean section was performed. Vacuum extraction was done in 15% vs 25% among S group and E group respectively. Oxytocin augmentation was needed in 48% vs 62% of the parturients among S group and E group respectively. Faetal heart rate disturbances following the spinal block were seen in 2 cases. Apgar score were high and no neonate had Apgar score <7 in both group. The overall cost was lower in S group compared to E group.ConclusionsBased on the results of our study we concluded that single dose spinal analgesia is a good alternative to epidural analgesia in controlling labour pain i.e. spinal compared to epidural is more easy performed, faster, less expensive, and provide effective analgesia.  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