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   1102篇
  免费   120篇
  国内免费   1篇
耳鼻咽喉   12篇
儿科学   14篇
妇产科学   10篇
基础医学   174篇
口腔科学   29篇
临床医学   61篇
内科学   243篇
皮肤病学   20篇
神经病学   24篇
特种医学   68篇
外科学   124篇
综合类   63篇
预防医学   65篇
眼科学   7篇
药学   53篇
中国医学   5篇
肿瘤学   251篇
  2023年   13篇
  2022年   23篇
  2021年   40篇
  2020年   31篇
  2019年   24篇
  2018年   48篇
  2017年   29篇
  2016年   32篇
  2015年   31篇
  2014年   40篇
  2013年   44篇
  2012年   69篇
  2011年   86篇
  2010年   56篇
  2009年   26篇
  2008年   60篇
  2007年   62篇
  2006年   57篇
  2005年   37篇
  2004年   55篇
  2003年   54篇
  2002年   44篇
  2001年   37篇
  2000年   35篇
  1999年   20篇
  1998年   11篇
  1997年   13篇
  1996年   7篇
  1995年   6篇
  1994年   9篇
  1993年   5篇
  1992年   14篇
  1991年   11篇
  1990年   14篇
  1989年   16篇
  1988年   6篇
  1987年   5篇
  1986年   3篇
  1985年   6篇
  1983年   5篇
  1982年   4篇
  1981年   4篇
  1979年   2篇
  1977年   2篇
  1975年   2篇
  1974年   6篇
  1969年   2篇
  1968年   2篇
  1967年   2篇
  1923年   3篇
排序方式: 共有1223条查询结果,搜索用时 15 毫秒
71.
Intensity-modulated radiation therapy (IMRT) for meningioma   总被引:2,自引:0,他引:2  
To assess the safety and efficacy of intensity-modulated radiation therapy (IMRT) in the treatment of intracranial meningioma.

Forty patients with intracranial meningioma (excluding optic nerve sheath meningiomas) were treated using IMRT with the NOMOS Peacock system between 1994 and 1999. Twenty-five patients received IMRT after surgery either as adjuvant therapy for incomplete resection or for recurrence, and 15 patients received definitive IMRT after presumptive diagnosis based on imaging. Thirty-two patients had skull base lesions, and 8 had nonskull base lesions. The prescribed dose ranged from 40 to 56 Gy (median 50.4 Gy) at 1.71 to 2 Gy per fraction, and the volume of the primary target ranged from 1.55 to 324.57 cc (median 20.22 cc). The mean dose to the target ranged from 44 to 60 Gy (median 53 Gy). Follow-up ranged from 6 to 71 months (median 30 months). Acute and chronic toxicity were assessed using Radiation Therapy Oncology Group (RTOG) morbidity criteria and tumor response was assessed by patient report, examination, and imaging. Overall survival, progression-free survival, and local control were calculated using the Kaplan-Meier method.

Cumulative 5-year local control, progression-free survival, and overall survival were 93%, 88%, and 89%, respectively. Two patients progressed after IMRT, one locally and one distantly. Each was treated with IMRT after multiple recurrences of benign meningioma over many years. Both were found to have malignant meningioma at the time of relapse after IMRT, and it is likely their tumors had already undergone malignant change by the time IMRT was given. Defined normal structures generally received a significantly lower dose than the target. The most common acute central nervous system (CNS) toxicity was mild headache, usually relieved with steroids. One patient experienced RTOG Grade 3 acute CNS toxicity, and 2 experienced Grade 3 or higher late CNS toxicity, with one possible treatment-related death. No toxicity was observed with mean doses to the optic nerve/chiasm up to 47 Gy and maximum doses up to 55 Gy.

IMRT is a promising new technology that is safe and efficacious in the primary and adjuvant treatment of intracranial meningiomas. A history of local aggression may indicate malignant degeneration and predict a poorer outcome. Toxicity data are encouraging, but the potential for serious side effects exists, as demonstrated by one possible treatment-related death. Larger cohort and longer follow-up are needed to better define efficacy and late toxicity of IMRT.  相似文献   

72.
BACKGROUND: Considerable experimental evidence and limited clinical evidence indicate that wound healing is impaired after trauma. Because Staphylococcus aureus peptidoglycan (SaPG) accelerates healing in normal rats and prevents wound healing impairment induced by glucocorticoids, cyclophosphamide, and streptozotocin-diabetes, we hypothesized that SaPG would prevent the impaired wound healing after trauma. METHODS: In each of two experiments, 18 Sprague-Dawley male rats were divided into two groups, nine rats each, paired by weight; one group received unilateral comminuted femoral fracture and wounding (two dorsal skin incisions and six subcutaneous polyvinyl alcohol [PVA] sponges), and the other group was only wounded. The incision and PVA sponges on one side were inoculated at operation with saline (200 microL/incision, 50 microL/sponge) and on the other side with SaPG in saline (860 microg of SaPG per centimeter of incision, 0.5 mg of SaPG per sponge). Rats ate chow and drank tap water ad libitum and were killed 7 days postoperatively. RESULTS: In both experiments, the wound breaking strength (WBS) of saline-inoculated incisions was significantly lower in rats with femoral fracture; histologically, reparative granulation tissue was looser and less prominent. WBS of SaPG-inoculated incisions in rats with and without femoral fracture was significantly higher than that of saline-inoculated incisions and, histologically, reparative tissue was more prevalent, more closely packed, and more mature. WBS of SaPG-inoculated incisions in rats with femoral fracture was similar to that of saline-inoculated incisions in rats without femoral fracture. Reparative tissue hydroxyproline and histologic findings of saline-inoculated PVA sponge reparative tissue were similar in all rats, as were the increases induced by SaPG inoculation. CONCLUSION: Wound breaking strength and histologic findings of skin incisions (impaired in rats with unilateral femoral fracture) are more sensitive to the adverse effects of trauma than accumulation of PVA sponge reparative tissue. A single inoculation of SaPG at operation increased wound incision healing in rats both without and with femoral fracture and notably prevented the impaired healing in rats with femoral fracture.  相似文献   
73.
Renal cell carcinoma (RCC) is a heterogeneous disease and its biology is poorly understood. The commonest subtype identified is clear cell RCC. The insulin-like growth factor axis is intimately involved with many cellular roles including that of renal development. Dysregulation of this axis has frequently been demonstrated in cancer. In this study, we examine the expression of several IGF-axis components, including receptors, ligands, and binding proteins in clear cell renal cell carcinoma. A series of clear cell RCCs with matched normal kidney from the same individuals were obtained. Total RNA was extracted and expression levels of genes examined using RNase protection analysis. We confirm the dysregulation of the IGF-axis within clear cell renal cell carcinoma including the upregulation of IGFBP-3, which is further validated by immunohistochemical staining on a tissue array containing 50 RCC: positive staining in 29/30 clear cell; 1/10 papillary and 0/10 chromophobe. In addition, we demonstrate that the expression of the A isoform of the insulin receptor is significantly upregulated, while that of IGFBP-5 are significantly downregulated in this tumour subtype.  相似文献   
74.
Paulino AC  Teh BS 《The New England journal of medicine》2005,352(22):2350-3; author reply 2350-3
  相似文献   
75.
OBJECTIVES: Systemic lupus erythematosus (SLE), a chronic illness with an unpredictable and variable course, profoundly affects the quality of life (QOL). General health questionnaires are used to assess QOL in SLE, but a disease-specific instrument could offer enhanced responsiveness and content validity. We detail the steps we took to develop and validate a new SLE-specific QOL instrument, SLEQOL. METHODS: Rheumatology professionals nominated items that they felt were important determinants of QOL of SLE patients. One hundred SLE patients were asked to assess the importance and frequency of occurrence of these items and to suggest those that had not been listed. Item reduction was performed using Rasch model and factor analyses to create a new questionnaire in English. This final questionnaire was administered to a cohort of 275 patients to study its psychometric properties. RESULTS: Fifty-one items covering a wide range of QOL concerns were identified. The patients' responses led to the elimination of 11. The new questionnaire of 40 items was found to have Cronbach's alpha of 0.95 and to consist of eight domains covering physical, mental and social QOL issues. It has good test-retest reliability, poor to fair cross-sectional correlation with the SF-36, with poor correlation with lupus activity or damage indices. The SLEQOL was more responsive to change than the SF-36. CONCLUSIONS: We have developed a new 40-item SLEQOL in English and showed that it is valid for use in SLE patients in Singapore. It offers better content validity and responsiveness to change than the SF-36.  相似文献   
76.
We have characterized a novel animal model of the common inflammatory skin disease seborrheic dermatitis (SD) that involves the expression of the self-specific 2C transgenic T cell receptor on the DBA/2 genetic background. Opportunistic fungal pathogens are present in the primary histological lesions and severe disease can be mitigated by the administration of fluconazole, demonstrating a role for infection in disease pathogenesis. Spontaneous disease convalescence occurs at 70-90 d of age and is preceded by an expansion of CD4+ T cells that partially restores the T cell lymphopenia that occurs in these animals. The adoptive transfer of syngeneic CD4+ T cells into pre-diseased DBA/2 2C mice completely abrogates the development of cutaneous disease. The pattern of disease inheritance in DBA/2 backcrosses suggests that one, or a closely linked group of genes, may control disease penetrance. Bone marrow reconstitution experiments demonstrated that the DBA/2 susceptibility factor(s) governing disease penetrance is likely non-hematopoietic since bone marrow from disease-resistant 2C mice can adoptively transfer the full disease phenotype to non-transgenic DBA/2 animals. This model implicates fungal organisms and CD4+ T cell lymphopenia in the development of a SD-like condition and, as such, may mimic the development of SD in acquired immunodeficiency syndrome.  相似文献   
77.
From a retrospective, cohort study of 205 patients diagnosed with full-thickness tears of the rotator cuff, we determined, using ultrasound, the prevalence of such tears in their 129 siblings. Using 150 spouses as controls, the relative risk of full-thickness tears in siblings versus controls was 2.42 (95% CI 1.77 to 3.31). The relative risk of symptomatic full-thickness tears in siblings versus controls was 4.65 (95% CI 2.42 to 8.63). The significantly increased risk for tears in siblings implies that genetic factors play a major role in the development of full-thickness tears of the rotator cuff.  相似文献   
78.
79.
BACKGROUND: Renal medullary carcinoma is a rare kidney tumor with highly aggressive behavior. This tumor occurs exclusively in young patients with sickle cell trait or disease. To the authors' knowledge, very little is known to date regarding the underlying molecular genetics of this tumor, and no effective therapy has been established. METHODS: The authors analyzed the gene expression profiles of 2 renal medullary carcinomas from patients with sickle cell trait using microarrays containing 21,632 cyclic DNA (cDNA) clones and compared them with the gene expression profiles of 64 renal tumors. RESULTS: Based on global gene clustering with 3583 selected cDNAs, the authors found a distinct molecular signature of renal medullary carcinoma, which clustered closely with urothelial (transitional cell) carcinoma of the renal pelvis, rather than renal cell carcinoma (RCC). This finding of a significant difference in the gene expression patterns of renal medullary carcinoma compared with RCC suggests that this tumor should not be treated as a conventional RCC but, rather, as a special malignancy. This study also identified genes/proteins that may serve as biomarkers for renal medullary carcinoma or as potential targets of novel therapies. In addition, comparative genomic microarray analysis allowed the authors to predict the lack of chromosomal imbalances in this tumor. CONCLUSIONS: To the authors' knowledge, the current study is the first molecular profiling of renal medullary carcinoma, a rare but highly aggressive kidney carcinoma. The genes that are expressed specifically in this tumor may lead to not only a better understanding of its molecular pathways and discoveries of novel diagnostic markers but also, more important, to effective therapeutic interventions.  相似文献   
80.
We report here the genetic findings of a new isolated familial somatotropinoma (IFS) kindred in which the mother (subject I:2) and one daughter (subject II:2) are affected; their ages at diagnosis were 25 and 14 years respectively. Additionally, patient I:2 developed virilization due to an androgen-secreting adrenocortical mass, presenting clinical and molecular features of sporadic adrenal carcinoma. To genotype this family and to narrow down the candidate interval of the putative IFS gene at 11q13, we performed haplotyping on the DNA from all five members of the family and allelotyping of one available somatotropinoma using polymorphic microsatellite markers from chromosome region 11q12.1-11q13.5. Results indicated that the disease haplotype, between markers D11S956 and D11S527, was transmitted from subject I:2 only to subject II:2. A meiotic recombination event was detected in the fraternal twin sister of II:2 (subject II:1), but her disease status is unknown. Since she is only 18 years old this genetic event cannot yet narrow down the area involved in the pathogenesis of IFS. Allelotyping of the somatotropinoma from II:2 revealed loss of the chromosome carrying the wild-type copy of the putative IFS gene inherited from her father. These results support the involvement of a tumor suppressor gene at 11q13.1-q13.3 in the pathogenesis of IFS.  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