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   425篇
  免费   31篇
  国内免费   3篇
耳鼻咽喉   6篇
儿科学   12篇
妇产科学   27篇
基础医学   61篇
口腔科学   32篇
临床医学   48篇
内科学   71篇
皮肤病学   5篇
神经病学   32篇
特种医学   8篇
外科学   39篇
综合类   8篇
预防医学   31篇
眼科学   20篇
药学   27篇
中国医学   5篇
肿瘤学   27篇
  2024年   2篇
  2023年   7篇
  2022年   18篇
  2021年   21篇
  2020年   25篇
  2019年   34篇
  2018年   33篇
  2017年   24篇
  2016年   27篇
  2015年   29篇
  2014年   19篇
  2013年   30篇
  2012年   43篇
  2011年   35篇
  2010年   14篇
  2009年   19篇
  2008年   24篇
  2007年   14篇
  2006年   16篇
  2005年   5篇
  2004年   5篇
  2003年   6篇
  2002年   5篇
  2001年   3篇
  1999年   1篇
排序方式: 共有459条查询结果,搜索用时 15 毫秒
121.
122.
BACKGROUND: The occurrence of basal cell carcinoma within a port-wine stain or nevus flammeus is rare. Sixteen cases of basal cell carcinoma which developed in a port-wine stain or nevus flammeus have been reported. OBJECTIVE: The objective was to demonstrate a rare case of basal cell carcinoma occurring in a port-wine stain successfully treated with Mohs micrographic surgery. METHODS: This is a case report and literature review. RESULTS: An 87-year-old man presented with a basal cell carcinoma on the margin of a previously untreated port-wine stain on the left cheek. Histologic examination showed a nodular basal cell carcinoma. The basal cell carcinoma was completely excised with Mohs micrographic surgery and complex linear closure was used to repair the wound in layers. The postoperative course was complicated by a hematoma, which developed 24 hr postoperatively. The hematoma was drained and there was no further bleeding or evidence of recurrence of the tumor after 12 months. CONCLUSION: Basal cell carcinoma should be included in the differential diagnosis of a skin lesion occurring in a port-wine stain.  相似文献   
123.
Identification of human papillomavirus in keratoacanthomas   总被引:1,自引:0,他引:1  
BACKGROUND: Keratoacanthomas are benign, clinically distinct skin tumors that may infiltrate and show cellular atypia. A viral etiology has been suggested, and the aim was to search for human papillomavirus (HPV) in keratoacanthomas. METHODS: From 21 immunosuppressed organ transplant recipients and 11 non-immunosuppressed patients, 72 fresh biopsies with diagnosis of keratoacanthomas were analyzed. For detection of cutaneous and genital HPV DNA, single-tube nested "hanging droplet" polymerase chain reaction (PCR) and another PCR (GP5+ and 6+) were used, respectively. RESULTS: Among 21 immunosuppressed patients, 71% (15/21) harbored HPV DNA at least in one sample. Of the keratoacanthoma lesions, 55% (33/60) were HPV DNA positive. Fourteen samples from eight immunosuppressed patients contained HPV types 5, 9, 10, 14, 19, 20, 21, 38, 49, 80, putative HPV types as HPVvs20-4, HPVvs75, and HPVvs92 and FA16.1, FA23.2, FA37, FA75, and FA81. Among 11 non-immunosuppressed patients, 36% (4/11) harbored HPV DNA at least in one sample, and 33% (4/12) of their keratoacanthomas were HPV DNA positive. In total, HPV DNA was detected in 51% (37/72) of the keratoacanthomas. CONCLUSIONS: By the use of PCR, cutaneous HPV DNA was detected in 51% (37/72) of the keratoacanthomas. No predominating HPV type or genital HPV type was identified. The role of HPV in keratoacanthomas remains thus elusive.  相似文献   
124.
125.
Evaluating the nutritional status of individuals and population groups is an important tool in public health and a feasible indicator of standards of living. The objective of this study was to determine the frequency of obesity and present nutritional status of university students of Iran University of Medical Sciences in Tehran. The survey was conducted between Oct 2004 and June 2005. The statistical population included all students from School of medicine, nursing and midwifery, health services, management, science, and rehabilitation. The method of sampling was multistage random. The sample size for the survey was 1,150 students. We used a self-administered 24h food recall questionnaire. We categorized BMI to two groups in bivariate analysis (BMI <25 kg m(-2) as obese and less than 25 kg m(-2) as non-obese). Mean BMI for all subjects was 21.7 +/- 2.9 kg m(-2). Almost 88% of the subjects were classified into a non-obese group (BMI <25 kg m(-2)). About 10% were underweight and 12.4% of the students had a BMI more than 25 kg m(-2). A significant difference was observed for BMI between males and females; 7.9% of males versus 22.5% of females had BMIs over 25. About 18% of students aged 23 years and over had BMIs over 25 versus 7.7% of students aged under 18. Intakes of fiber, pre-vitamin A, folacin and iron were significantly different between BMI groups. Intakes of these nutrients were higher in the obese students than the students with BMIs less than 25 kg m(-2). Our results indicate that about 12.4% of the students had a BMI more than 25 kg m(-2). There was a significant association between BMI, and smoking habits, age, sex, place of resident and having specific dietary regimen.  相似文献   
126.
Keratoacanthoma (KA) is a benign keratinocytic neoplasm that usually presents as a solitary nodule on sun-exposed areas, develops within 6-8 weeks and spontaneously regresses after 3-6 months. KAs share features such as infiltration and cytological atypia with squamous cell carcinomas (SCCs). Furthermore, there are reports of KAs that have metastasized, invoking the question of whether or not KA is a variant of SCC. To date no reported criteria are sensitive enough to discriminate reliably between KA and SCC, and consequently there is a clinical need for discriminating markers. We screened fresh frozen material from 132 KAs and 37 SCCs for gross chromosomal aberrations by using comparative genomic hybridization (CGH). Forty-nine KAs (37.1%) and 31 SCCs (83.7%) showed genomic aberrations, indicating a higher degree of chromosomal instability in SCCs. Gains of chromosomal material from 1p, 14q, 16q, 20q, and losses from 4p were seen significantly more frequently in SCCs compared with KAs (P-values 0.0033, 0.0198, 0.0301, 0.0017, and 0.0070), whereas loss from 9p was seen significantly more frequently in KAs (P-value 0.0434). The patterns of recurrent aberrations were also different in the two types of neoplasms, pointing to different genetic mechanisms involved in their developments.  相似文献   
127.
We report a new mononuclear molybdenum(iv) complex, MoOLBISLSQ, in which LSQ (2,4-di-tert-butyl o-semibenzoquinone ligand) has been prepared from the reaction of the o-iminosemibenzoquinone form of a tridentate non-innocent benzoxazole ligand, LBIS, and MoO2(acac)2. The complex was characterized by X-ray crystallography, elemental analysis, IR and UV-vis spectroscopy and magnetic susceptibility measurements. The crystal structure of MoOLBISLSQ revealed a distorted octahedral geometry around the metal centre, surrounded by one O and two N atoms of LBIS and two O atoms of LSQ. The effective magnetic moment (μeff) of MoOLBISLSQ decreased from 2.36 to 0.2 μB in the temperature range of 290 to 2 K, indicating a singlet ground state caused by antiferromagnetic coupling between the metal and ligand centred unpaired electrons. Also, the latter led to the EPR silence of the complex. Cyclic voltammetry (CV) studies indicate both ligand and metal-centered redox processes. MoOLBISLSQ was applied as a catalyst for the oxidative cleavage of cyclohexene to adipic acid and selective oxidation of sulfides to sulfones with aqueous hydrogen peroxide.

Biradical molybdenum(iv) complex, MoOLBISLSQ, has been prepared from the reaction of the o-iminosemibenzoquinone form of a tridentate non-innocent benzoxazole ligand, LBIS, and MoO2(acac)2 and used as catalyst in oxidation reaction..  相似文献   
128.
Intravenous immunoglobulin (IVIg) is one of the first‐line therapies for inflammatory neuropathies. Clinical use of IVIg for these disorders is limited by expense and availability. Here, we investigated a synthetic product alternative to IVIg. The aim of this study was to test the therapeutic efficacy of a novel recombinant polyvalent murine IgG2a Fc compound (stradomer?) in experimental autoimmune neuritis (EAN). Seventy‐four Lewis rats were immunized with myelin, randomized into three groups, and were treated with albumin, IVIg, or stradomer at 1% of IVIg dose. Rats were assessed clinically, electrophysiologically, and histologically. The clinical disease severity was evaluated by clinical grading and weight changes. The electrophysiological studies recorded motor conduction velocity (MCV), amplitudes, and latencies of the evoked compound muscle action potential (CMAP) and spinal somatosensory evoked potential. The treatment efficacy of the IVIg and stradomer groups was compared to the albumin (control) group. We demonstrate that stradomer has a similar therapeutic efficacy to human IVIg in EAN. Rats receiving stradomer or IVIg showed significantly lower clinical scores and less prominent weight loss compared with controls. A statistically significant improvement in both MCV and the amplitudes of distal and proximal evoked CMAP was observed in the stradomer and IVIg groups. Finally, treatment with both IVIg and stradomer resulted in statistically less inflammation and demyelinating changes in the sciatic nerve as evidenced by lower histological grade. These results reveal the potential of using fully recombinant multimerized immunoglobulin Fc instead of IVIg for treating inflammatory neuropathies.  相似文献   
129.
Purpose: The aim of this prospective randomized controlled clinical study was to assess the crestal bone loss and the implant stability in implants that were placed by the osteotome technique compared with the conventional drilling technique. Materials and Methods: Forty‐six screw type Straumann SLA® oral implants (Straumann AG, Waldenburg, Switzerland) were inserted in the anterior segment of maxilla of 30 patients. The implant site was prepared randomly using either osteotome technique (test group) or the conventional drilling technique (control group). Radio frequency analysis (RFA) values at implant placement and after 3 months were recorded. The crestal bone loss was measured using digital subtraction radiography technique after 3, 6, and 12 months. Results: RFA demonstrated a statistically significant higher primary stability for implants in the osteotome group than that of the conventional group (p = .026) at the time of implant insertion. However, there was no statistically significant difference between both groups 3 months after the surgery (p = .06). At month 3, the osteotome group caused significantly more crestal bone loss than the conventional group (p = .04). At months 6 and 12, both groups had comparable bone levels (p = .29). Conclusion: Osteotome technique yielded higher primary stability than conventional drilling technique. However, this technique was not superior to conventional technique after 3 months.  相似文献   
130.
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