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   588篇
  免费   22篇
  国内免费   2篇
耳鼻咽喉   18篇
儿科学   46篇
妇产科学   54篇
基础医学   35篇
口腔科学   34篇
临床医学   47篇
内科学   90篇
皮肤病学   2篇
神经病学   30篇
特种医学   46篇
外科学   124篇
综合类   9篇
预防医学   7篇
眼科学   26篇
药学   13篇
肿瘤学   31篇
  2023年   7篇
  2022年   9篇
  2021年   13篇
  2020年   12篇
  2019年   15篇
  2018年   15篇
  2017年   13篇
  2016年   20篇
  2015年   19篇
  2014年   18篇
  2013年   29篇
  2012年   37篇
  2011年   29篇
  2010年   20篇
  2009年   15篇
  2008年   36篇
  2007年   46篇
  2006年   37篇
  2005年   66篇
  2004年   22篇
  2003年   30篇
  2002年   29篇
  2001年   15篇
  2000年   11篇
  1999年   10篇
  1998年   2篇
  1996年   2篇
  1995年   3篇
  1994年   2篇
  1991年   2篇
  1990年   5篇
  1989年   6篇
  1988年   1篇
  1986年   4篇
  1985年   3篇
  1984年   1篇
  1983年   2篇
  1978年   2篇
  1973年   1篇
  1972年   1篇
  1971年   2篇
排序方式: 共有612条查询结果,搜索用时 0 毫秒
1.
Targeting in a cellular level is still one of the major challenges in biomedical treatments. However, new synthetic and analytical techniques now allow the development of precisely prepared macromolecules. Thus, glycopolymer chains are reported to be prepared with controlled length, monomer sequences, as well as chain‐folded structures. A high level of complexity in synthetic macromolecules also allows increased selectivity in targeting, which is a key factor in biomedical applications.  相似文献   
2.
3.
C.T.-guided stereotactic destructive pain procedures; percutaneous cordotomy, trigeminal tractotomy-nucleotomy and extralemniscal myelotomy are presented. All procedures were applied in 32 cases without any mispuncture or complication. Advantages of C.T. guidance are direct visualization of target electrode relations, measurements of spinal cord diameters at the lesion site, and demonstration of spinal cord displacement during the procedure.  相似文献   
4.
This study aimed to evaluate human antibody responses to diphtheria toxin subunits in various age groups. Antibodies against the intact diphtheria toxin and the diphtheria toxin subunits A and B were evaluated in 1319 individuals using a double-antigen ELISA. Although high levels of protection (83.6%, 95% CI 79.2-87.4) were found in children and adolescents, the middle-aged adult population was less protected (28.8%, 95% CI 24.3-33.6). An increase in age was associated with a decrease in the frequency of protected individuals in the 0-39-year age group (p <0.001). Anti-subunit B levels correlated well (p <0.01) with levels of antibodies against the intact toxin. In children aged < or =16 years, the intervals at which the peaks in geometric mean titres of anti-subunit B antibodies were observed were found to correlate with the ages at which booster doses are administered. Overall, males appeared to be more protected than females (OR 1.67, 95% CI 1.34-2.08, p <0.001). A small group of individuals had antibody levels of > or =0.1 IU/mL against the intact toxin, but did not have protective antibody against subunit B. Determination of anti-subunit B antibody levels should help in evaluating the effectiveness of diphtheria boosters and other aspects of diphtheria immunity.  相似文献   
5.
Purpose: to determine wheather an association exists between sensorineural hearing loss and pseudoexfoliation. Methods: Hearing thresholds were determined by using pure-tone au-diometry in 75 patients with pseudoexfoliation syndrome and in the control group of 75 subjects without pseudoexfoliation The groups were sex and age matched. Results: The frequency of  相似文献   
6.
Subclinical adrenocortical insufficiency in renal amyloidosis   总被引:1,自引:0,他引:1  
In order to investigate the functional significance of possible adrenal amyloid infiltration in patients with renal amyloidosis, we performed corticotrophin stimulation tests in 15 patients having renal amyloidosis with no clinical evidence of adrenocortical insufficiency and 12 controls. In 7 of the patients, the cortisol increments obtained during the test were found to be consistent with primary adrenal insufficiency due to possible amyloid infiltration of the adrenal cortex; in contrast, in all control subjects, adrenal responses to the test were regarded as sufficient for proper adrenal function.  相似文献   
7.
The aim of this study was to record sacral bone morphometry that may help in selection of the implant type and proper size in sacroiliac separation. For this reason, sacral lengths and width, the length of each sacral vertebrae, distances between cranial and caudal articular processes, vertical and transversal diameters of the cranial endplate, sacral tuberositas and articular surface areas were obtained from 11 dogs. Additionally, the transverse and vertical diameters of the bony structure and sacral canal were measured from six cross-sections. The data of the study were determined to be representative of the sacral values for average-sized dogs, which was confirmed statistically. The highest value was the sacral width among the linear measurements. The ventral sacral length was longer than the dorsal sacral length. The total lateral area of the sacral wing was measured as 677.46 (142.1)mm2. The transverse diameters of the first sacral vertebra important for screw implantation were 46.02 (4.33)mm and 44.18 (5.29)mm in the first and second cross-sections, respectively.  相似文献   
8.
Caffeine is widely consumed among elite athletes for its well-known ergogenic properties, and its ability to increase exercise performance. However, studies to date have predominantly focused on the anhydrous form of caffeine in male participants. The aim of the study was to investigate the effect of caffeinated coffee ingestion on lower-upper body muscular endurance, cognitive performance, and heart rate variability (HRV) in female athletes. A total of 17 participants (mean ± standard deviation (SD): age = 23 ± 2 years, body mass = 64 ± 4 kg, height = 168 ± 3 cm) in a randomized cross-over design completed three testing sessions, following the ingestion of 3 mg/kg/bm of caffeine (3COF), 6 mg/kg/bm of caffeine (6COF) provided from coffee or decaffeinated coffee (PLA) in 600 mL of hot water. The testing results included: (1) repetition number for muscular endurance performance; (2): reaction time and response accuracy for cognitive performance; (3): HRV parameters, such as standard deviation of normal-to-normal (NN) intervals (SDNN), standard deviation of successive differences (SDSD), root mean square of successive differences (RMSSD), total power (TP), the ratio of low- and high-frequency powers (LF/HF), high-frequency power (HF), normalized HF (HFnu), low-frequency power (LF), and normalized LF (LFnu). A one-way repeated measures ANOVA revealed that 3COF (p = 0.024) and 6COF (p = 0.036) improved lower body muscular endurance in the first set as well as cognitive performance (p = 0.025, p = 0.035 in the post-test, respectively) compared to PLA. However, no differences were detected between trials for upper body muscular endurance (p = 0.07). Lastly, all HRV parameters did not change between trials (p > 0.05). In conclusion, ingesting caffeinated coffee improved lower body muscular endurance and cognitive performance, while not adversely affecting cardiac autonomic function.  相似文献   
9.
OBJECTIVE: To evaluate and compare the analgesic efficacy and adverse effects of tramadol and pethidine in labor. METHOD: Fifty-nine full term parturients were randomly assigned to one of two groups in active labor. Group 1 received 100 mg pethidine; group 2, 100 mg tramadol, intramuscularly. Analgesic efficacy, maternal side effects, changes in the blood pressure, heart rate, and duration of labor were assessed. RESULT: At 30 and 60 min after drug administration, pain relief was greater in the pethidine group than in tramadol group. The incidence of nausea and fatigue was higher in the tramadol group. Following drug administration the decrease in systolic and diastolic blood pressure and the increase in heart rate were statistically significant in both groups. No significant difference was found between the groups when compared for duration of labor and Apgar scores. None of the neonates developed respiratory depression. CONCLUSION: Pethidine seems to be a better alternative than tramadol in obstetric analgesia because of its superiority in analgesic efficacy and low incidence of maternal side effects.  相似文献   
10.
Introduction:Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disease characterised by multisystemic involvement, including bone tissue. Deformities and reduced bone mass are the main bone manifestations in NF1. Quantitative computed tomography (QCT) provides true volumetric bone mineral density (BMD) measurement. This study aimed to evaluate bone metabolism parameters and BMD in children with NF1 using QCT.Methods:The data of 52 paediatric NF1 patients (23 female, 29 male) was evaluated retrospectively. We investigated anthropometric measurements, biochemical parameters like total calcium, phosphate, magnesium, alkaline phosphatase, 25-hydroxyvitamin D (25OHD), parathyroid hormone, calcitonin, urinary calcium/creatinine ratio, and QCT parameters like lumbar trabecular and cortical BMD, trabecular area and cortical thickness. Comparisons of gender and puberty status were performed.Results:25% of patients had skeletal deformities and 42.3% had 25OHD inadequacy (<20 ng/mL). The frequency of 25OHD inadequacy was significantly higher in pubertal/postpubertal patients than prepubertal patients (61.9% vs. 29.0%, P = 0.019). Trabecular BMD Z-score was <−2.0 in 11.5% of patients; all with low BMD were at the pubertal/postpubertal stage. There was a significant negative correlation between age and trabecular Z-score (r = −0.41, P = 0.003). Mean cortical BMD was statistically similar between the genders and puberty groups. Puberty status, anthropometric Z-scores, and biochemical and QCT parameters were statistically similar between the genders (P > 0.05).Conclusion:Paediatric NF1 patients may present with low BMD and 25OHD inadequacy, especially at puberty. QCT may be a useful tool to evaluate trabecular and cortical bone separately in NF1 patients.  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