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   1258篇
  免费   54篇
  国内免费   62篇
耳鼻咽喉   22篇
儿科学   36篇
妇产科学   27篇
基础医学   136篇
口腔科学   104篇
临床医学   129篇
内科学   233篇
皮肤病学   22篇
神经病学   45篇
特种医学   94篇
外科学   235篇
综合类   23篇
预防医学   97篇
眼科学   8篇
药学   83篇
中国医学   3篇
肿瘤学   77篇
  2022年   24篇
  2021年   41篇
  2020年   21篇
  2019年   25篇
  2018年   37篇
  2017年   22篇
  2016年   23篇
  2015年   31篇
  2014年   45篇
  2013年   48篇
  2012年   67篇
  2011年   62篇
  2010年   40篇
  2009年   43篇
  2008年   48篇
  2007年   89篇
  2006年   38篇
  2005年   41篇
  2004年   36篇
  2003年   32篇
  2002年   17篇
  2001年   19篇
  2000年   30篇
  1999年   33篇
  1998年   33篇
  1997年   43篇
  1996年   30篇
  1995年   29篇
  1994年   15篇
  1993年   29篇
  1992年   7篇
  1991年   17篇
  1990年   17篇
  1989年   32篇
  1988年   11篇
  1987年   21篇
  1986年   22篇
  1985年   23篇
  1984年   20篇
  1983年   16篇
  1982年   11篇
  1981年   9篇
  1980年   19篇
  1979年   4篇
  1978年   7篇
  1976年   6篇
  1975年   5篇
  1973年   4篇
  1970年   3篇
  1966年   3篇
排序方式: 共有1374条查询结果,搜索用时 15 毫秒
41.
The aim of this study was to report an unusual case of mucoepidermoid carcinoma (MEC) in a 39-year-old woman. The tumor showed a prominent population of clear and intermediate basal cells. Clear cells rarely predominate over other cell types. Such cases are called clear cell variant of MEC. The case also revealed a variable amount of calcified material in the tumor mass. Calcifications are rare in clear cell MEC. These structures were periodic acid-Schiff positive and diastase resistant, excluding glycogen origin. Immunohistochemistry was performed, and the epidermoid component was positive for cytokeratin (CK)7, CK13, CK14, and CK19. The mucous and clear cells presented mild staining for CK7. Cytokeratins 7, 13, and 19 stained luminal cells, and intermediate cells exhibited positivity for CK7, CK14, and vimentin. The origin of the calcifications is speculated to be the result of dystrophic calcification of the amorphous eosinophilic material secreted by intermediate basal cells.  相似文献   
42.
43.
Caseous lymphadenitis (CL), caused by a pathogen of the second class of biosafety – Corynebacterium pseudotuberculosis, is a chronic and severe infectious disease that affects small ruminants and requires long, ineffective treatment which generally leads to animal sacrifice so as to stop the disease spreading. The infected animals suffer the excision of affected superficial lymph nodes and post-surgical treatment with iodine (10% solution in ethanol) and, sometimes, prolonged antibiotic use, but only if the sick animals are of great importance to breeding. Herein, we propose a cheap and easy to apply treatment of CL with excellent results using biogenic silver nanoparticles (AgNP) based technology. AgNP antibacterial properties were investigated in vitro against Corynebacterium pseudotuberculosis cells and in vivo on small ruminants with CL. Treatment of surgical wounds resulting from the excision of superficial CL lesions with a AgNP-based cream was compared to the standard post-surgical treatment method by iodine. Also, the effects of AgNP-based cream treatment were evaluated and compared with the effects of the iodine CL treatment by serum NMR-based metabolomics. Serum samples were collected from 29 animals, 9 sheep and 20 goats, during the treatments and analyzed. All animals showed stable serum metabolomes when iodine or AgNP-based cream effects were compared. The AgNP-based cream treatment showed excellent results, especially in accelerating the healing of wounds, which occurred two to three times faster in comparison with the iodine treatment. AgNP-based cream treatment also prevented CL reappearance and did not cause any side effects on animals. This is the first report on very effective post-surgical treatment of superficial CL in small ruminants based on biogenic silver nanoparticles, which might open up the possibility for a safe veterinary application of AgNP-based cream.

Biogenic nanosilver in a pharmaceutical cream for wound healing in animal and human healthcare.  相似文献   
44.
45.
IntroductionPhysical training has been recommended to improve overall well-being in patients with fibromyalgia. Body relaxation exercises also seem to have some beneficial effect, however there is no consensus regarding this modality.ObjectiveComparing the effectiveness of sophrology and resistance training in improving the pain of women with fibromyalgia.MethodA randomized controlled clinical trial with a blind evaluator. Sixty (60) women with a medical diagnosis of fibromyalgia were randomized and included in two groups: sophrology group (SG) who participated in a relaxation program based on sophrology (n = 30), and resistance group (RG) (n = 30) who participated in a resistance training program for biceps, pectoral, triceps, knee extensors, trapezius, knee flexors, hip abductors. Both groups were treated twice a week for 12 weeks and reevaluated every 4 weeks. The assessment instruments used were the Visual Analog Scale for Pain (VAS), the one-repetition maximum test (1 RM), the overall quality of life (SF-36), the 6-min walk test (6MWT), the Timed Up and Go test (TUG) and the Fibromyalgia Impact Questionnaire (FIQ).ResultsWe found that the RG presented statistically significant decreases in pain (VAS) during the evaluations (p < 0.05) and increased strength of the evaluated muscles (p < 0.05). A statistically significant decrease in pain (p < 0.05) was observed in the SG compared to T0, with no significant differences in muscle strength. Differences between groups were observed, with better indices only for 6MWT and functional capacity domain of the SF36 for the RG (p < 0.05).ConclusionNo differences in pain were found between the groups. Resistance training was more effective than sophrology in improving strength and functional capacity of women with fibromyalgia.  相似文献   
46.
Peripheral blood stem cells (PBSCs) mobilized with high-dose chemotherapy and hematopoietic growth factors are now widely used to support myeloablative therapy of multiple myeloma and effect complete remissions in up to 50% of patients with apparent extension of event- free and overall survival. Because tumor cells are present not only in bone marrow, but also in virtually all PBSC harvests, it is conceivable that autografted myeloma cells contribute to relapse after autotransplants. In this study, the kinetics of mobilization of normal hematopoietic stem cells were compared with those of myeloma cells present in PBSC harvests of 12 patients after high-dose cyclophosphamide and granulocyte-macrophage colony-stimulating factor administration. CD34+ and CD34+Lin-Thy+ stem cell contents were measured by multiparameter flow cytometry, and myeloma cells were quantitated by immunostaining for the relevant Ig light chain and by a quantitative polymerase chain reaction for the myeloma-specific CDRIII sequence. Results indicated marked heterogeneity in the percentages of mobilized stem cells among different patients (0.1% to 22.2% for CD34+ cells and 0.1% to 7.5% for CD34+Lin-Thy+ cells, respectively). The highest proportions of hematopoietic progenitor cells were observed early during apheresis, with 9 of 12 patients mobilizing adequate amounts of CD34+ cells for 2 autotransplants (> 4 x 10(6)/kg) within the first 2 days, whereas peak levels (percent and absolute numbers) of myeloma cells were present on days 5 and 6 (0.5% to 22.0%). During the last days of collection, mobilized tumor cells exhibited more frequently high labeling index values (1% to 10%; median, 4.4%) and an immature phenotype (CD19+). The differential mobilization observed between normal hematopoietic stem cells and myeloma cells can be exploited to reduce tumor cell contamination in PBSC harvests.  相似文献   
47.
This prospective multicentric randomized open trial was designed to evaluate the efficacy of ranitidine 150 mg bid vs 300 mg nocte in the short-term (4 weeks) treatment of duodenal ulcer in 15 Brazilian centers. On the basis of a randomization table 190 patients with endoscopically confirmed duodenal ulcer were allocated to receive either ranitidine 150 mg bid (94 pts) or 300 mg nocte (96 pts). The 2 treatment groups were well matched for age, sex, duration of ulcer disease, number and size of ulcers, duration of current episode, intensity of ulcer pain, alcohol and coffee intake and smoking habits. They were endoscopically controlled at the end of the 4 weeks. At 4 weeks 78 of 94 patients (83.0%) had their ulcers healed with the 150 mg bid regimen as opposed to 79 of 96 patients (82.3%) allocated to the 300 mg nocte dosage. This difference was not statistically significant. Ulcer symptoms diminished with treatment in both groups. The tolerability and compliance was excellent in both groups. The results show that ranitidine 300 mg nocte is as effective in the short-term treatment of duodenal ulcer as ranitidine 150 mg bid. Considering the greater simplicity of administration enhancing patient compliance, the treatment with 300 mg nocte is preferable.  相似文献   
48.
Chen  CL; Fuscoe  JC; Liu  Q; Relling  MV 《Blood》1996,88(6):2210-2218
Etoposide is one of the most widely used antineoplastics. Unfortunately, the same treatment schedules associated with impressive efficacy are associated with an increased risk of secondary acute myeloid leukemia (AML), which has prompted its withdrawal from some treatment regimens, thereby potentially compromising efficacy against the original tumor. Because etoposide-associated AML is characterized by site-specific illegitimate DNA recombination, we studied whether etoposide could directly cause site-specific deletions of exons 2 and 3 in the hprt gene. Human lymphoid CCRF-CEM cells were treated with etoposide for 4 hours, and DNA was isolated after subculturing. The deletion of exons 2 and 3 from hprt was assayed by a quantitative polymerase chain reaction (PCR) method. In the absence of etoposide treatment, the frequency of deletions of exons 2 and 3 was very low (5.05 x 10(-8)). After exposure to 10 mumol/ L etoposide, the frequency of the exon 2 + 3 deletion was increased immediately after and at 24 hours after etoposide treatment (65 to 89 x 10(-8)) and increased to higher levels (128 to 173 x 10(-8)) after 2 and 6 days of subculture (P < .001 overall). The frequency of the exon 2 + 3 deletion assessed at 6 days of subculture after 4 hours of 0, 0.25, 1, 2.5, 5, and 10 mumol/L etoposide treatment increased with etoposide concentration, ie, 5.05 x 10(-8), 89.2 x 10(-8), 108 x 10(-8), 142 x 10(-8), 163 x 10(-8), and 173 x 10(-8), respectively (P < .0001). Sequencing of a subset of amplified products confirmed the presence of DNA sequences at the breakpoints consistent with V(D)J recombination. By contrast, exon 2 + 3 deletions after etoposide treatment in the myeloid cell lines KG-1A and K562 showed no evidence of V(D)J recombinase in their genesis. We conclude that etoposide can induce the illegitimate site-specific action of V(D)J recombinase on an unnatural DNA substrate after a single treatment in human lymphoid cells.  相似文献   
49.
Some evidences suggest the involvement of the central nervous system in patients infected with SARS-CoV-2. We aim to analyze possible associations between coronavirus disease 2019 (COVID-19) pandemic and spontaneous subarachnoid hemorrhage (SAH), in a comprehensive neurological center.We conducted a retrospective case series of 4 patients infected by COVID-19, who developed spontaneous SAH. Clinical data were extracted from electronic medical records.Between March 24, 2020, and May 22, 2020, 4 cases (3 females; 1 male) of SAH were identified in patients infected with SARS-CoV-2, in a comprehensive neurological center in Brazil. The median age was 55.25 years (range 36 -71). COVID-19-related pneumonia was severe in 3 out of 4 cases, and all patients required critical care support during hospitalization. The patients developed Fisher grade III and IV SAH. Digital subtraction angiography (DSA) was performed in 3 of the 4 patients. However, in only 1 case, an aneurysm was identified. Inflammatory blood tests were elevated in all cases, with an average D-dimer of 2336 μg/L and mean C-reactive protein (CRP) of 3835 mg/dl The outcome was poor in the majority of the patients, with 1 death (25%); 2 (50%) remained severely neurologically affected (mRS:4); and 1 (25%) had slight disability (mRS:2).This study shows a series of 4 rare cases of SHA associated with COVID-19. The possible mechanisms underlying the involvement of SARSCoV-2 and SHA is yet to be fully understood. Therefore, SHA should be included in severe neurological manifestations in patients infected by this virus.  相似文献   
50.

Introduction

This study aimed to analyze cases referred from a reference service in oral pathology that were initially misdiagnosed as periapical lesions of endodontic origin and to perform a review of the literature regarding lesions located in the apical area of teeth with a nonendodontic source.

Methods

A survey was made of clinical cases derived from the service of oral pathology from 2002 to 2012. The pertinent literature was also reviewed using ScienceDirect and PubMed databases. The lesions were grouped into benign lesions mimicking endodontic periapical lesions (BLMEPLs), malignant lesions mimicking endodontic periapical lesions (MLMEPLs), and Stafne bone cavities. The clinical presentations were divided into lesions with swelling without pain, lesions with swelling and pain, and lesions without swelling but presenting with pain.

Results

The results showed that 66% (37/56) of cases represented benign lesions, 29% (16/56) malignant lesions, and 5% (3/56) Stafne bone cavities. The most commonly reported BLMEPLs were ameloblastomas (21%) followed by nasopalatine duct cysts (13.5%). The most frequently cited MLMEPLs were metastatic injuries (31.5%) followed by carcinomas (25%). The main clinical presentation of BLMEPLs was pain, whereas that of MLMEPLs was swelling associated with pain; Stafne bone cavities displayed particular clinical findings.

Conclusions

Clinical and radiologic aspects as well as the analysis of the patients' medical history, pulp vitality tests, and aspiration are essential tools for developing a correct diagnosis of periapical lesions of endodontic origin. However, if the instruments mentioned earlier indicate a lesion of nonendodontic origin, a biopsy and subsequent histopathological analysis are mandatory.  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