全文获取类型
收费全文 | 902篇 |
免费 | 58篇 |
国内免费 | 10篇 |
专业分类
儿科学 | 20篇 |
妇产科学 | 17篇 |
基础医学 | 82篇 |
口腔科学 | 25篇 |
临床医学 | 84篇 |
内科学 | 186篇 |
皮肤病学 | 10篇 |
神经病学 | 12篇 |
特种医学 | 107篇 |
外科学 | 55篇 |
综合类 | 42篇 |
预防医学 | 41篇 |
眼科学 | 4篇 |
药学 | 17篇 |
肿瘤学 | 268篇 |
出版年
2023年 | 4篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 3篇 |
2015年 | 14篇 |
2014年 | 13篇 |
2013年 | 20篇 |
2012年 | 21篇 |
2011年 | 34篇 |
2010年 | 34篇 |
2009年 | 25篇 |
2008年 | 22篇 |
2007年 | 43篇 |
2006年 | 38篇 |
2005年 | 29篇 |
2004年 | 39篇 |
2003年 | 24篇 |
2002年 | 27篇 |
2001年 | 20篇 |
2000年 | 17篇 |
1999年 | 29篇 |
1998年 | 34篇 |
1997年 | 35篇 |
1996年 | 45篇 |
1995年 | 26篇 |
1994年 | 24篇 |
1993年 | 22篇 |
1992年 | 15篇 |
1991年 | 20篇 |
1990年 | 30篇 |
1989年 | 29篇 |
1988年 | 29篇 |
1987年 | 20篇 |
1986年 | 24篇 |
1985年 | 17篇 |
1984年 | 16篇 |
1983年 | 16篇 |
1982年 | 10篇 |
1981年 | 18篇 |
1980年 | 7篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 5篇 |
排序方式: 共有970条查询结果,搜索用时 13 毫秒
941.
Voynov G Kaufman S Hong T Pinkerton A Simon R Dowsett R 《American journal of clinical oncology》2002,25(6):606-611
Malignant gliomas are usually refractory to aggressive combined-modality therapy, and the incidence of recurrence and death after treatment is very high. State-of-the-art techniques such as stereotactic intensity-modulated radiation therapy (IMRT) are now available to deliver a high dose of radiation to the tumor with relative preservation of surrounding tissues to achieve optimal tumor coverage with minimal toxicity. We report 10 patients (median age 48 years) with recurrent malignant gliomas that were treated with stereotactic directed IMRT. Initial tumor histologies included one low grade glioma (upgraded to anaplastic astrocytoma at recurrence), four anaplastic astrocytomas, and four glioblastomas multiforme. One patient was originally presumed to have a brain metastasis secondary to renal cell carcinoma but was pathologically confirmed as having glioblastoma multiforme at the time of recurrence. Before recurrence, all patients had been treated with external beam radiation therapy (median 59.7 Gy). All recurrences were confirmed by a subtotal resection (5/10) or by imaging (5/10). The median Karnofsky performance score at the time of IMRT was 80. The median tumor volume was 34.69 cm. Treatment was delivered on a 10-MV linear accelerator with a mini-multileaf collimator, MIMiC, and planned with Peacock/Corvus software. Radiation was delivered in daily fractions of 5 Gy, to a total median dose of 30 Gy at the 71% to 93% median isodose line. Median overall survival time was 10.1 months from the date of stereotactic treatment, with 1- and 2-year survival rates of 50% and 33.3%, respectively. Fractionated stereotactic intensity modulated radiation therapy is a novel technique used in the treatment of recurrent malignant gliomas, which produces results comparable to other currently used stereotactic techniques. 相似文献
942.
Mei-Fen Chan Mitch Dowsett Elizabeth Folkerd Sheila Bingham Nicholas Wareham Robert Luben Ailsa Welch Kay-Tee Khaw 《Cancer epidemiology, biomarkers & prevention》2007,16(5):900-905
BACKGROUND: Short-term trials indicate that intensive physical activity may influence endogenous sex hormone concentrations. However, the relationship between usual daily physical activity and endogenous hormones in postmenopausal women in the general population is still uncertain. OBJECTIVE AND METHODS: To determine the relationship between usual physical activity and endogenous sex hormones in postmenopausal women. A cross-sectional population-based study of 2,082 postmenopausal women ages 55 to 81 years, residing in the general community of Norfolk, United Kingdom, and not currently using hormone replacement therapy were chosen to participate. Physical activity in the past 1 year was assessed using a validated questionnaire, and endogenous sex hormone and sex hormone-binding globulin (SHBG) concentrations were determined. RESULTS: Usual physical activity levels were inversely associated with circulating concentrations of testosterone and estradiol, testosterone/SHBG ratio, and positively associated with SHBG. These associations were only slightly attenuated after adjusting for potential covariates including body mass index, smoking status, alcohol intake, and reproductive variables. Testosterone concentrations and testosterone/SHBG ratios were 19% [95% confidence interval (95% CI), 9-27%, P < 0.001] and 24.0% (95% CI, 13-34% P < 0.001) lower, respectively, whereas estradiol concentrations were 6% (95% CI, 0-12%; P < 0.05) lower in the highest compared with lowest activity levels, respectively. A decreasing trend for the estradiol/SHBG ratio and 17alpha-hydroxyprogesterone concentrations was also observed. Androstenedione levels did not differ significantly according to physical activity. CONCLUSIONS: Higher usual physical activity levels among postmenopausal women seem to be related to lower endogenous testosterone and estradiol concentrations. This may be one mechanism that could partly explain the reported inverse relationship between physical activity and breast cancer risk in some studies. 相似文献
943.
Studies of rhinovirus resistant to an antiviral chalcone 总被引:3,自引:1,他引:3
During studies of the antiviral activity of chalcone Ro-09-0410 on human rhinovirus type 9 (RV9) chalcone-resistant strains of RV9 were isolated and appeared with a frequency of about 10(-5) in chalcone sensitive stock. Chalcone-dependent viruses were found after further passage. Some characteristics of the resistant viruses were studied and compared with those of the wild type virus; a number of differences were detected. They produced smaller plaques and grew to lower titre; they were no longer protected by chalcone from inactivation by heat and low pH. The event responsible for drug dependence apparently took place after that responsible for drug resistance. Drug-resistant viruses were still sensitive to dichloroflavan and enviroxime. 相似文献
944.
Prognostic value of O‐6‐methylguanine–DNA methyltransferase (MGMT) protein expression in glioblastoma excluding nontumour cells from the analysis 下载免费PDF全文
945.
S Kanala S Gudipalli P Perumalla K Jagalanki PV Polamarasetty S Guntaka A Gudala RP Boyapati 《Annals of the Royal College of Surgeons of England》2021,103(1):18
IntroductionMaxillofacial fractures are often associated with severe morbidity, functional deficit, disfigurement and significant financial implications. The aim of this review was to investigate whether the aetiology, prevalence and management modalities of facial trauma can identify the common causes of facial trauma with a view to recommending measures to the appropriate governing bodies to change the current practice wherever possible.MethodsThe records of 1,112 patients referred to our oral and maxillofacial unit in Andhra Pradesh, India, between February 2008 and October 2017 were analysed retrospectively. Data including age, sex, aetiology, fracture site and treatment were evaluated.ResultsMen aged 20–40 years were the most common victims of facial trauma. Road traffic accidents (RTAs) were responsible in 70% of cases. Mandibular fractures constituted 47% of the overall fractures, and 55% of the total fractures were treated with open reduction and internal fixation.ConclusionsThe main cause of maxillofacial injury among patients reporting to our hospital was RTAs. Mandibular fractures were the most common, accounting for almost half of the cases. Over half (55%) of all maxillofacial fractures were treated with open reduction and internal fixation. Reasons for this high frequency may include the large number of poorly maintained, overloaded vehicles on unsuitable roads, violation of traffic regulations (particularly by inexperienced young drivers), abuse of alcohol or other intoxicating agents and the sociocultural behaviours of some drivers. 相似文献
946.
van der Flier S Chan CM Brinkman A Smid M Johnston SR Dorssers LC Dowsett M 《International journal of cancer. Journal international du cancer》2000,89(5):465-468
High BCAR1/p130Cas expression in primary breast tumour cytosol predicts a poor chance of response recurrent disease to tamoxifen treatment in patients with oestrogen receptor (ER)-positive breast carcinomas. In this study, we assessed whether BCAR1/p130Cas expression is altered during acquisition of anti-oestrogen resistance. BCAR1/p130Cas protein was quantitatively measured by chemiluminescent Western blot analysis in the cytosol of 34 predominantly ER(+) carcinomas that initially responded to primary tamoxifen treatment and subsequently progressed (n = 22 ) or developed during adjuvant tamoxifen treatment (n = 12) and compared to 54 untreated ER(+) human breast carcinomas. We did not detect significant differences in the level of BCAR1/p130Cas protein in untreated and acquired tamoxifen-resistant carcinomas. Our results indicate that in tumour progression towards tamoxifen resistance, increase of BCAR1/p130Cas may be only one of the molecular mechanisms. Thus, high BCAR1/p130Cas protein levels appear to be a hallmark for intrinsic resistance to tamoxifen in breast carcinomas. 相似文献
947.
Brown GM; Furlong RA; Sargent CA; Erickson RP; Longepied G; Mitchell M; Jones MH; Hargreave TB; Cooke HJ; Affara NA 《Human molecular genetics》1998,7(1):97-107
DFFRY (the Y-linked homologue of the DFFRX Drosophila fat-facets related X
gene) maps to proximal Yq11.2 within the interval defining the AZFa
spermatogenic phenotype. The complete coding region of DFFRY has been
sequenced and shows 89% identity to the X-linked gene at the nucleotide
level. In common with DFFRX , the potential amino acid sequence contains
the conserved Cys and His domains characteristic of ubiquitin C-terminal
hydrolases. The human DFFRY mRNA is expressed in a wide range of adult and
embryonic tissues, including testis, whereas the homologous mouse Dffry
gene is expressed specifically in the testis. Analysis of three azoospermic
male patients has shown that DFFRY is deleted from the Y chromosome in
these individuals. Two patients have a testicular phenotype which resembles
Sertoli cell-only syndrome, and the third diminished spermatogenesis. In
all three patients, the deletions extend from close to the 3' end into the
gene, removing the entire coding sequence of DFFRY. The mouse Dffry gene
maps to the Sxrb deletion interval on the short arm of the mouse Y
chromosome and its expression in mouse testis can first be detected between
7.5 and 10.5 days after birth when type A and B spermatogonia and
pre-leptotene and leptotene spermatocytes are present.
相似文献
948.
In vivo radiolabeling of platelet proteins: a new method with identification of platelet factor XIII
A method for radiolabeling platelets in vivo was developed in which 3H- arginine was injected into the bone marrow of normal dogs. On the third day after injection, a maximum of 6%--7% of the radioactivity had been incorporated into the total platelet mass. This method of isotope administration resulted in a 50--60-fold increase in maximum uptake of radiolabel by platelets, as compared to values obtained by others using intravenous injections of various radioactive compounds. Tritium- labeled platelets were harvested from the animals and then were washed to remove unbound 3H-arginine. On polyacrylamide gel electrophoresis 7 labeled protein bands, with molecular weights ranging from 29,000to 132,000, were obtained from the platelet-soluble fraction. One 3H- containing protein with a molecular weight of 81,000 was identified immunologically and enzymatically as platelet factor XIII. 相似文献
949.
Marrow transplantation for acute lymphoblastic leukemia: factors affecting relapse and survival 总被引:3,自引:5,他引:3
Barrett AJ; Horowitz MM; Gale RP; Biggs JC; Camitta BM; Dicke KA; Gluckman E; Good RA; Herzig RH; Lee MB 《Blood》1989,74(2):862-871
Transplant outcome was analyzed in 690 recipients of bone marrow transplants (BMTs) for acute lymphoblastic leukemia (ALL) in first (n = 299) or second remission (n = 391). Actuarial 5-year leukemia-free survival was 42% +/- 9% (95% confidence interval) and 26% +/- 6%, respectively; relapse rates were 29% +/- 9% and 52% +/- 8%, respectively. Five-year leukemia-free survival was 56% +/- 18% in children and 39% +/- 10% in adults (P less than .02) transplanted in first remission. In first-remission adults, non-T-cell phenotype, male to female donor-recipient sex-match and graft-v-host disease (GVHD) were associated with decreased leukemia-free survival; inclusion of corticosteroids in the regimen to prevent GVHD was associated with increased leukemia-free survival. Variables associated with decreased leukemia-free survival after second-remission transplants were age greater than or equal to 16 years and relapse occurring while on therapy. Variables associated with increased probability of relapse were similar for first- and second-remission transplants and included GVHD prophylaxis without methotrexate and absence of GVHD. In first- remission transplants, leukocyte count greater than or equal to 50 x 10(9)/L at diagnosis was also associated with increased relapse; in second remission, relapse while receiving chemotherapy was also associated with increased posttransplant relapse. These data emphasize the importance of both disease- and transplant-related variables in predicting outcome after BMT. They may be used to explain differences between studies, design future trials, and identify persons most likely to benefit from BMT. 相似文献
950.
RP Jones NA Stylianides AG Robertson VSK Yip G Chadwick 《Annals of the Royal College of Surgeons of England》2015,97(5):386-389
IntroductionGastrointestinal (GI) endoscopy is an important skill for both gastroenterologists and general surgeons but concerns have been raised about the provision and delivery of training. This survey aimed to evaluate and compare the delivery of endoscopy training to gastroenterology and surgical trainees in the UK.MethodsA nationwide electronic survey was carried out of UK gastroenterology and general surgery trainees.ResultsThere were 216 responses (33% gastroenterologists, 67% surgeons). Gastroenterology trainees attended more non-training endoscopy lists (mean: 3.0 vs 1.2) and training lists than surgical trainees (mean: 0.9 vs 0.5). A significantly higher proportion of gastroenterologists had already achieved accreditation in gastroscopy (60.8% vs 28.9%), colonoscopy (66.7% vs 1.4%) and flexible sigmoidoscopy (33.3% vs 3.0%). More gastroenterology trainees aspired to achieve accreditation in gastroscopy (97.2% vs 79.2%), flexible sigmoidoscopy (91.7% vs 70.1%) and colonoscopy (88.8% vs 55.5%) by completion of training. By completion of training, surgeons were less likely than gastroenterologists to have completed the required number of procedures to gain accreditation in gastroscopy (60.3% vs 91.3%), flexible sigmoidoscopy (64.6% vs 68.6%) and colonoscopy (60.3% vs 70.3%).ConclusionsThis survey highlights marked disparities between surgical and gastroenterology trainees in both aiming for and achieving accreditation in endoscopy. Without changes to the delivery and provision of training as well as clarification of the role of endoscopy training in a surgical training programme, future surgeons will not be able to perform essential endoscopic assessment of patients as part of their management algorithm. 相似文献