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   583篇
  免费   28篇
  国内免费   6篇
耳鼻咽喉   43篇
儿科学   18篇
妇产科学   22篇
基础医学   53篇
口腔科学   7篇
临床医学   45篇
内科学   124篇
皮肤病学   5篇
神经病学   26篇
特种医学   18篇
外科学   181篇
综合类   11篇
预防医学   7篇
眼科学   19篇
药学   14篇
中国医学   1篇
肿瘤学   23篇
  2024年   1篇
  2023年   2篇
  2022年   8篇
  2021年   9篇
  2020年   7篇
  2019年   8篇
  2018年   9篇
  2017年   15篇
  2016年   17篇
  2015年   19篇
  2014年   16篇
  2013年   38篇
  2012年   37篇
  2011年   38篇
  2010年   34篇
  2009年   24篇
  2008年   61篇
  2007年   61篇
  2006年   62篇
  2005年   47篇
  2004年   45篇
  2003年   21篇
  2002年   26篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1996年   2篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1978年   1篇
  1977年   1篇
排序方式: 共有617条查询结果,搜索用时 15 毫秒
101.
We examined the lower limb joint kinematics observed during pre- and postflight treadmill walking performed by seven subjects from three Space Shuttle flights flown between March 1992 and February 1994. Basic temporal characteristics of the gait patterns, such as stride time and duty cycle, showed no significant changes after flight. Evaluation of phaseplane variability across the gait cycle suggests that postflight treadmill walking is more variable than preflight, but the response throughout the course of a cycle is joint dependent and, furthermore, the changes are subject dependent. However, analysis of the phaseplane variability at the specific locomotor events of heel strike and toe off indicated statistically significant postflight increases in knee variability at the moment of heel strike and significantly higher postflight hip joint variability at the moment of toe off. Nevertheless, the observation of component-specific variability was not sufficient to cause a change in the overall lower limb joint system stability, since there was no significant change in an index used to evaluate this at both toe off and heel strike. The implications of the observed lower limb kinematics for head and gaze control during locomotion are discussed in light of a hypothesized change in the energy attenuation capacity of the musculoskeletal system in adapting to weightlessness.  相似文献   
102.
There is a little information in literature about circulating asymmetric dimethylarginine (ADMA) concentrations in polycystic ovary syndrome (PCOS) and the results reported are discrepant. In this study, therefore, we aimed (1) to determine the circulating ADMA concentrations in 44 women with PCOS and 22 age- and BMI-matched healthy controls, (2) to evaluate its correlations with insulin resistance, gonadotrophins, and androgen secretion, and (3) to compare effects of metformin and ethinyl estradiol-cyproterone acetate (EE/CPA) treatments on circulating ADMA concentrations. In conclusion, our data indicate that circulating ADMA concentrations in non-obese, non-hypertensive and young women with PCOS are significantly higher than healthy controls and they improved by a 3-month course of metformin and oral contraceptive treatments.  相似文献   
103.
Recently, it has been indicated that beta lactam antibiotics offer neuroprotection by increasing glutamate transporter expression. Furthermore, these antibiotics have been shown to prevent the development of tolerance and dependence to opioids. Since cannabinoid tolerance is known to be similar to opioids, our purpose was to examine the effect of ceftriaxone on the development of tolerance to WIN 55,212-2, a cannabinoid agonist. The tail flick test, a rectal thermometer, and the ring test were used for evaluating the degree of tolerance to the analgesic, hypothermic, and cataleptic effects of WIN 55,212-2, respectively. Within one week, animals became completely tolerant to analgesic, hypothermic and cataleptic effects of WIN 55,212-2 (6 mg/kg). Ceftriaxone, with its higher doses (100-200 mg/kg), attenuated the development of tolerance to the analgesic and hypothermic effects of WIN 55,212-2, but had no effect on its cataleptic action. Dihydrokainic acid (10 mg/kg), a GLT-1 transporter inhibitor, prevented this effect of ceftriaxone. Our results suggest that repeated treatment with ceftriaxone prevents the development of tolerance to the analgesic and hypothermic effects of cannabinoids, and GLT-1 activation appears to play a key role in this preventive effect of beta-lactam antibiotics.  相似文献   
104.
The aim of the present study was to develop a new experimental pain model by adapting the chronic constriction injury (CCI) model of the sciatic nerve to the exclusively sensory saphenous nerve in rats. Animals were divided into naïve, sham, and two experimental groups, in which two or four 4-0 chromic gut ligatures were loosely ligated around the saphenous nerve. Then, behavioral signs of neuropathic pain were observed for 8 weeks. In rats with four ligatures, prominent mechanical allodynia and thermal hyperalgesia developed; these behavioral signs were not prominent in rats with two ligatures. Pharmacological analysis was made in rats with four loose ligations; morphine and WIN 55,212-2, a cannabinoid agonist, reversed all of the modalities tested, whereas gabapentin only suppressed mechanical allodynia and amitriptyline only reduced mechanical hyperalgesia. Our data establish a rat model of saphenous CCI with significant allodynia and hyperalgesia, which is sensitive to a number of analgesic compounds.  相似文献   
105.
106.
107.
The advances in neuroimaging have improved clinicoanatomic correlations in patients with stroke. Junctional infarct is a distinct term, used to describe border zone infarcts of the posterior fossa. We presented computed tomography (CT) and magnetic resonance imaging (MRI) findings in a rare case of bilateral symmetrical junctional infarcts between the superior cerebellar artery (SCA) and posterior inferior cerebellar artery (PICA) territories. In addition to precise knowledge of arterial territories required to achieve accurate localization of ischemic lesions on CT and MRI, the radiologist must also be aware of radiologic features and geographic territories of cerebellar arteries and their junctional infarctions.  相似文献   
108.
OBJECTIVE: The purpose of this study was to evaluate the role of CYP1A1*3 gene polymorphism in the development of cervical cancer by comparing patients having cervical intraepithelial neoplasia (CIN) or invasive cervical cancer with control subjects. METHODS: CYP1A1*3 polymorphism was analyzed using an allele-specific PCR-based method. RESULTS: In the group of patients with CIN, the frequency of the Ile/Val and of any Val alleles was significantly higher than in the healthy control subjects (OR: 4.51; 95%CI = 2.42-8.43, and OR: 3.71; 95%CI = 2.03-6.78). In the CIN1 group, patients with Ile/Val and any Val genotypes were found to be significantly higher (OR: 10.53; 95%CI = 3.78-29.33 and OR: 8.38; 95%CI = 3.04-23.08). In the CIN2 group, patients with Ile/Val and any Val revealed a 4.06- and 3.23-fold higher risk than those with Ile/Ile (95%CI = 1.54-10.74 and 1.24-8.45). However, the variance in the group of patients with CIN3 did not reach statistical significance. Patients with cervical cancer were analyzed with respect to the histological diagnoses. In the adenocancer group, the estimated ORs with respect to the control subjects were 11.29 for Ile/Val (95%CI = 3.35-38.07) and 8.98 for any Val groups (95%CI = 2.69-30.01), with a statistical significance. Among the squamous cell cancer patients, Ile/Val and any Val were significantly higher than in controls (OR: 5.76; 95%CI = 3.13-10.59 and OR: 5.20; 95%CI = 2.91-9.28). Although Val/Val genotype did not reach a significant value, it was near significance with an OR of 3.03 (95%CI = 0.95-9.68). CONCLUSION: These results suggest that CYP1A1*3 gene polymorphism is linked to a propensity for cervical carcinogenesis and further series are needed to detect the exact role of this unique variation.  相似文献   
109.
Transcanalicular dacryocystorhinostomy (TCDCR) with diode laser is a minimally invasive technique with good cosmetic results. The reported complication rate is low. In this brief report, the authors describe a patient with tissue necrosis and nasal-cutaneous fistula after TCDCR. A 65-year-old woman attended the authors' clinic 1 month after TCDCR. Examination revealed a large tissue defect and nasal-cutaneous fistula in the medial canthal region. Aspergillus growth was noted in culture specimens taken from the nasal cavity. The patient was treated with intravenous amphotericin B. The treatment resulted in granulation and closure of the defect.  相似文献   
110.
BACKGROUND: Actinobacillus actinomycetemcomitans is a major pathogen in aggressive periodontitis. Our objectives were to determine the periodontal status and occurrence of A. actinomycetemcomitans in family members of subjects with A. actinomycetemcomitans-positive aggressive periodontitis (AgP) and to evaluate the probability of its intrafamilial transmission. METHODS: Of the 300 subjects screened, 66 (22%) had AgP and A. actinomycetemcomitans. Eleven (probands) of these 66 subjects with AgP met the strict inclusion criteria for the study. The study population consisted of 55 subjects, including probands and their family members (N = 44). Two family groups were formed according to whether the proband was a child (N = 7) or a parent (N = 4). Subgingival samples from all subjects were cultured for A. actinomycetemcomitans, and its clonal types were determined by combining serotype and genotype data for each isolate. RESULTS: Among 42 dentate family members, 16 (38%) exhibited periodontitis and eight (50%) had AgP. Periodontitis was found in nine of 12 (75%) of the dentate parents and six of 17 (35%) siblings of the child probands. A. actinomycetemcomitans was detected in 16 of 31 (52%) family members, i.e., one parent and at least one sibling in six families. The child probands shared A. actinomycetemcomitans clonal types with their parents in five of six (83%) families and with their siblings in three of six (50%) families. In the four parent-proband families, A. actinomycetemcomitans occurred in two spouses and all nine children. The parent probands shared A. actinomycetemcomitans clonal types with their spouses in both families and with their children in three of four families. In all families, the likelihood of intrafamilial transmission of A. actinomycetemcomitans was statistically significant. Members of most families (eight of 11, 73%) also harbored additional clonal types of A. actinomycetemcomitans. CONCLUSION: Parents and siblings of an individual with A. actinomycetemcomitans-positive AgP may have an increased susceptibility to periodontitis and shared and/or other clonal types of oral A. actinomycetemcomitans.  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