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   1157篇
  免费   68篇
  国内免费   3篇
耳鼻咽喉   26篇
儿科学   47篇
妇产科学   15篇
基础医学   135篇
口腔科学   23篇
临床医学   101篇
内科学   292篇
皮肤病学   15篇
神经病学   119篇
特种医学   105篇
外科学   82篇
综合类   4篇
预防医学   56篇
眼科学   18篇
药学   85篇
中国医学   2篇
肿瘤学   103篇
  2021年   12篇
  2020年   15篇
  2019年   15篇
  2018年   17篇
  2017年   21篇
  2016年   20篇
  2015年   27篇
  2014年   40篇
  2013年   54篇
  2012年   67篇
  2011年   73篇
  2010年   50篇
  2009年   33篇
  2008年   64篇
  2007年   78篇
  2006年   58篇
  2005年   61篇
  2004年   82篇
  2003年   85篇
  2002年   74篇
  2001年   9篇
  2000年   15篇
  1999年   13篇
  1998年   13篇
  1997年   15篇
  1996年   12篇
  1995年   12篇
  1994年   17篇
  1993年   11篇
  1992年   7篇
  1991年   9篇
  1990年   13篇
  1989年   6篇
  1988年   17篇
  1987年   5篇
  1986年   5篇
  1985年   10篇
  1984年   8篇
  1982年   5篇
  1981年   6篇
  1979年   4篇
  1975年   5篇
  1974年   4篇
  1972年   6篇
  1971年   7篇
  1970年   5篇
  1969年   6篇
  1968年   6篇
  1967年   5篇
  1966年   8篇
排序方式: 共有1228条查询结果,搜索用时 15 毫秒
1.
2.
This study aimed to measure the active mandibular range of motion (ROM) (mouth opening: MO; right and left lateral movements: RL and LL; protrusion: P) in Brazilian children of both genders and of various ages, weights, and heights, and to establish correlations among such variables. Study subjects (n = 303) were healthy boys and girls, with ages ranging between 6 and 14 years, who were regular students of a public school in the state of S?o Paulo. Analysis of variance and intra-class correlation coefficients were considered significant for p < 0.05. Weak significant correlations were observed between mandibular ROM and age, height, and weight. No statistically significant differences (p > 0.05) were observed regarding mandibular ROM between gender groups. Mean mandibular ROM values showed significant increases (p < 0.05) in relation to age, height, and weight, except for RL (p > 0.05), in the studied age range. Significantly smaller (p < 0.05) mean mandibular ROM values were observed for the intervals of 6 and 7 years of age, 1.15-1.35 m, and 17.30-26.50 kg, in relation to the other ranges. Nonetheless, no differences were observed among mean mandibular ROM values in the ranges 8 to 12-14 years, 1.36-1.75 m, and 47-85 kg. Thus, it is suggested that weight, height, and age variables be considered when obtaining mandibular ROM values, particularly in children aged 6 to 7 years, measuring 1.15-1.35 m, and weighing between 17.3-46.5 kg.  相似文献   
3.
4.
5.
Purpose: Ictal fear is an uncommon condition in which fear manifests as the main feature of epileptic seizures. The literature has suggested that ictal fear is generally associated with poor seizure outcomes. We wanted to clarify the variability in seizure outcome of children with ictal fear. Subjects and methods: We identified five pediatric patients with ictal fear who were followed up on at Okayama University Hospital between January 2003 and December 2012. We retrospectively reviewed their clinical records and EEG findings. Results: The onset age of epilepsy ranged from 8 months to 9 years and 10 months. The common ictal symptoms were sudden fright, clinging to someone nearby, and subsequent impairment of consciousness, which were often accompanied by complex visual hallucinations and psychosis-like complaints. Ictal fear, in four patients, was perceived as a nonepileptic disorder by their parents. Ictal electroencephalograms (EEG) of ictal fear were obtained in all patients. Three showed frontal onset, while the other two showed centrotemporal or occipital onsets. Two patients were seizure free at last follow-up, while seizures persisted in the other three. A patient with seizure onset during infancy had a favorable outcome, which was considered to be compatible with benign partial epilepsy with affective symptoms. Conclusion: Ictal fear is not always associated with a symptomatic cause or a poor seizure outcome. It is quite important to make a correct diagnosis of ictal fear as early as possible to optimize treatment.  相似文献   
6.
Objective: We intended to investigate the effects of age, gender, and medications on amino acid cerebrospinal fluid (CSF)/plasma ratios in children, and to determine whether amino acid transports across the blood–CSF barrier in children differ from those in adults. Patients and methods: Amino acid concentrations measured by ion-exchange high-performance liquid chromatography were used (CSF from 99 children, simultaneously collected plasma from 76 children). Influence of age, gender, and medications on the amino acid CSF concentrations and CSF/plasma ratios were analyzed by linear multiple regression. Interactions of amino acid transports were analyzed by correlation analysis of CSF/plasma ratios. Results: CSF/plasma ratios of serine, valine, histidine, and arginine were higher in younger children. The glutamate CSF/plasma ratio was higher in older children. Serine, alanine, threonine, valine, and histidine CSF/plasma ratios were lower in females. Glutamine, methionine, tyrosine, and phenylalanine CSF/plasma ratios were elevated with valproate therapy. Serine, threonine, valine, leucine, and tyrosine CSF/plasma ratios were lower with clobazam therapy. The asparagine CSF/plasma ratio was elevated with pyridoxal phosphate therapy. Transports of most essential neutral amino acids interacted with each other, as did neutral amino acids with low molecular weights. Cationic amino acids interacted with each other and some essential neutral amino acids. Acidic amino acids had no interactions with other amino acids. Conclusions: Age, gender, and anti-epileptic drugs affect amino acid CSF/plasma ratios in children. Transport interactions between amino acids in children showed no remarkable difference from those of adults and generally followed the substrate specificities of multiple amino acid transport systems.  相似文献   
7.
Although numerous sources of evidence show that regular physical activity is beneficial to health, most individuals do not engage in a sufficient amount of physical activity to meet the guidelines set out by expert panels. In addition, the minimum amount of physical activity associated with reduced cardiovascular disease risk markers is not clear in older adults. The purpose of this study was to determine the effects of a 12-week walking program involving an exercise volume below the current minimum physical activity recommendation on cardiovascular disease risk markers in older adults. The participants were recruited from the following two groups separately: a walking group (n = 14) and a control group (n = 14). In the walking group, participants walked 30 to 60 minutes per session on 2 days per week for 12 weeks (average walking time, 49.4 ± 8.8 min/session). Plasma oxidised low-density lipoprotein concentrations tended to be lower than baseline values in the walking group after 12 weeks (paired t-test, p = 0.127). The ratio of oxidised low-density lipoprotein to high-density lipoprotein cholesterol was significantly lower than the baseline ratio in the walking group after 12 weeks (paired t-test, p = 0.035). Resting systolic blood pressure and diastolic blood pressure were significantly lower than baseline values in the walking group after 12 weeks (paired t-tests, p = 0.002, p < 0.0005, respectively). Our findings demonstrate that a 12-week walking program comprising a low volume of physical activity confers a benefit to cardiovascular-related health in older adults.

Key Points

  • It is important to consider baseline physical activity levels when evaluating physical activity program.
  • Being physically active is important to reduce the potential risk marker of cardiovascular disease in older adults.
  • These data imply that a small volume of 12-week walking program confers a benefit to cardiovascular-related health in older adults.
Key words: blood pressure, exercise, lipid metabolism, older adults, oxidised low-density lipoprotein  相似文献   
8.
9.

Purpose

In the recent years in Japan, an increasing number of patients with neuroblastoma (NB) are being treated by the “delayed local treatment (DL)” policy, undergoing surgery after the completion of high-dose chemotherapy with hematopoietic stem cell rescue (HDC). We reviewed the histopathological findings of second-look operations, including those of patients treated with DL.

Patients

From 1998 to 2013, 26 patients with high-risk NB underwent radical operation following chemotherapy. Surgery was performed after induction chemotherapy in 17 cases (standard; STD), whereas 9 cases completed induction chemotherapy and HDC before undergoing tumor resection (DL). The amount of necrosis and the degree of differentiation within the post-treatment tumor were assessed.

Results

Eighty-eight percent of the tumors showed necrosis in more than 1/3 of the specimen. Two DL cases showed complete disappearance of viable tumor cells. Amount of necrosis did not affect the prognosis of the patient. Tumors with immature, poorly differentiated phenotypes showed an extremely aggressive thereafter. Though not statistically proven, 123I-MIBG (metaiodobenzylguanidine) uptake may be correlated with the amount of viable cells remaining within the tumor, but not with the degree of differentiation.

Conclusions

Our results support the previous reports advocating that tumors that sustain unfavorable histology after chemotherapy behave aggressively thereafter.  相似文献   
10.
The mode of action of (1′S,2′R)-9-{[1′,2′-bis(hydroxymethyl)cycloprop-1′-yl]methyl}guanine (A-5021) against herpes simplex virus type 1 (HSV-1), HSV-2, and varicella-zoster virus (VZV) was studied. A-5021 was monophosphorylated at the 2′ site by viral thymidine kinases (TKs). The 50% inhibitory values for thymidine phosphorylation of A-5021 by HSV-1 TK and HSV-2 TK were comparable to those for penciclovir (PCV) and lower than those for acyclovir (ACV). Of these three agents, A-5021 inhibited VZV TK most efficiently. A-5021 was phosphorylated to a mono-, di-, and triphosphate in MRC-5 cells infected with HSV-1, HSV-2, and VZV. A-5021 triphosphate accumulated more than ACV triphosphate but less than PCV triphosphate in MRC-5 cells infected with HSV-1 or VZV, whereas HSV-2-infected MRC-5 cells had comparable levels of A-5021 and ACV triphosphates. The intracellular half-life of A-5021 triphosphate was considerably longer than that of ACV triphosphate and shorter than that of PCV triphosphate. A-5021 triphosphate competitively inhibited HSV DNA polymerases with respect to dGTP. Inhibition was strongest with ACV triphosphate, followed by A-5021 triphosphate and then (R,S)-PCV triphosphate. A DNA chain elongation experiment revealed that A-5021 triphosphate was incorporated into DNA instead of dGTP and terminated elongation, although limited chain extension was observed. Thus, the strong antiviral activity of A-5021 appears to depend on a more rapid and stable accumulation of its triphosphate in infected cells than that of ACV and on stronger inhibition of viral DNA polymerase by its triphosphate than that of PCV.  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