全文获取类型
收费全文 | 1912篇 |
免费 | 215篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 95篇 |
妇产科学 | 37篇 |
基础医学 | 242篇 |
口腔科学 | 49篇 |
临床医学 | 145篇 |
内科学 | 411篇 |
皮肤病学 | 29篇 |
神经病学 | 67篇 |
特种医学 | 65篇 |
外科学 | 488篇 |
综合类 | 29篇 |
一般理论 | 7篇 |
预防医学 | 107篇 |
眼科学 | 37篇 |
药学 | 91篇 |
1篇 | |
中国医学 | 1篇 |
肿瘤学 | 164篇 |
出版年
2023年 | 12篇 |
2022年 | 29篇 |
2021年 | 76篇 |
2020年 | 35篇 |
2019年 | 57篇 |
2018年 | 78篇 |
2017年 | 62篇 |
2016年 | 48篇 |
2015年 | 67篇 |
2014年 | 78篇 |
2013年 | 77篇 |
2012年 | 100篇 |
2011年 | 130篇 |
2010年 | 62篇 |
2009年 | 64篇 |
2008年 | 93篇 |
2007年 | 94篇 |
2006年 | 75篇 |
2005年 | 73篇 |
2004年 | 63篇 |
2003年 | 47篇 |
2002年 | 52篇 |
2001年 | 45篇 |
2000年 | 41篇 |
1999年 | 39篇 |
1998年 | 14篇 |
1997年 | 12篇 |
1996年 | 16篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 31篇 |
1991年 | 37篇 |
1990年 | 23篇 |
1989年 | 25篇 |
1988年 | 17篇 |
1987年 | 23篇 |
1986年 | 23篇 |
1985年 | 24篇 |
1984年 | 19篇 |
1983年 | 28篇 |
1980年 | 12篇 |
1979年 | 19篇 |
1978年 | 17篇 |
1977年 | 9篇 |
1976年 | 12篇 |
1974年 | 14篇 |
1973年 | 18篇 |
1972年 | 24篇 |
1971年 | 13篇 |
1970年 | 17篇 |
排序方式: 共有2130条查询结果,搜索用时 15 毫秒
111.
Dipen J Parekh Donna Pauler Ankerst Jacques Baillargeon Betsy Higgins Elizabeth A Platz Dean Troyer Javier Hernandez Robin J Leach Anna Lokshin Ian M Thompson 《Cancer epidemiology, biomarkers & prevention》2007,16(10):1966-1972
OBJECTIVE: We analyzed the association of 54 biomarkers from seven classes including adipokines, immune response metalloproteinases, adhesion molecules, and growth factors with prostate cancer risk adjusting for the Prostate Cancer Prevention Trial (PCPT) risk score. METHODS: A total of 123 incident prostate cancer cases and 127 age-matched controls were selected from subjects in the San Antonio Center for Biomarkers of Risk of Prostate Cancer cohort study. Prediagnostic serum concentrations were measured in the sample collected at baseline using LabMAP technology. The odds ratios (OR) of prostate cancer risk associated with serum concentrations of 54 markers were estimated using univariate conditional logistic regression before and after adjustment for the PCPT risk score. Two-way hierarchical unsupervised clustering techniques were used to evaluate whether the 54-marker panel distinguished cases from controls. RESULTS: Vascular endothelial growth factor, resistin, interleukin 1Ra (IL-1Ra), granulocyte colony-stimulating factor, matrix metalloproteinase-3, plasminogen activator inhibitor, and kallikrein-8 were statistically significantly (P < 0.05) underexpressed in prostate cancer cases, and alpha-fetoprotein was statistically significantly overexpressed in prostate cancer cases, but all had area underneath the receiver-operating characteristic curve <60%; none were statistically significant adjusting for multiple comparisons (P < 0.0008) or after adjustment for the PCPT risk score. Statistical clustering of patients by the marker panel did not distinguish a separate group of cases from controls. CONCLUSIONS: This age-matched case-control study did not support findings of increased diagnostic potential from a 54-marker panel when compared with the conventional risk factors incorporated in the PCPT risk calculator. Future discovery of new biomarkers should always be tested and compared against conventional risk factors before applying them in clinical practice. 相似文献
112.
Cardiac surgery is associated with a systemic inflammatory response and systemic coagulopathy, which can result in significant organ dysfunction and bleeding. Aprotinin, a serine protease inhibitor, can limit systemic inflammation, and has been associated with myocardial, pulmonary and cerebral protection in addition to its proven haemostatic efficacy. Data are currently conflicting regarding the haemostatic efficacy of aprotinin relative to alternative agents including tranexamic acid. Recent studies have demonstrated aprotinin usage is associated with increased rates of thrombotic and renal complications, but these findings are at odds with the majority of studies relating to aprotinin safety to date. The lack of adequately powered, randomised studies evaluating aprotinin and alternative agents limits drawing conclusions about the complete use or disuse of aprotinin presently and requires individualised patient selection based on bleeding risk and co-morbidities for its usage. 相似文献
113.
M Rao N Eid L Herrod A Parekh P Steiner 《American journal of diseases of children (1960)》1986,140(8):825-828
We investigated the antidiuretic hormone (ADH) response in 12 infants with bronchopulmonary dysplasia during acute respiratory distress. All of the infants had hypoxemia with air-trapping in the chest at the time of admission to the hospital. None had documented infection. There was a dramatic increase in the plasma levels of ADH during acute respiratory distress, with a subsequent reduction of levels toward normal when the respiratory distress decreased to the preadmission well state. Three of 12 infants manifested hyponatremia at 24 hours after admission, with two of them exhibiting persistent hypertension for up to three days. The mechanism for elevated ADH levels is air-trapping in the chest, causing pulmonary hypovolemia and decreased left atrial filling and/or decreased transmural pressure of the left atrium. 相似文献
114.
Y Heloury T Gunness J Y Cohen M P Quere M Meignier J C Le Neel 《Annales de pédiatrie》1988,35(6):377-381
115.
Nicholas J. Berg H. Bryan Neel Louis H. Weiland Thomas C. Spelsberg 《The Laryngoscope》1987,97(3):286-290
A new assay has been developed to predict the effectiveness of steroid-hormone therapy in various tumors. The Biopsy Nuclear Binding assay measures the amount of biologically active receptor that binds both steroid hormone and acceptor sites in the nucleus. This assay does not measure the entire receptor population, only those that are biologically active; therefore, it should more accurately predict the response to steroid-hormone therapy. We applied this assay effectively in breast and endometrial carcinoma. Preliminary studies have shown that 40% of patients with head and neck squamous-cell carcinomas have biologically active (nuclear bound) progesterone receptors. If nuclear binding predicts a remission with hormonal therapy, then the quality of life of appropriately selected patients could greatly improve. 相似文献
116.
Cantin B Giannetti N Parekh H Panchal SN Kwok BW Najem R Woodman K Hunt SA Valantine HA 《Clinical transplantation》2002,16(3):196-201
BACKGROUND: When used in conjunction with steroids and cyclosporin, mycophenolate mofetil (MMF) has been shown to significantly reduce mortality and incidence of rejection in the first year after heart transplantation. It also appears that in this early post-transplantation period, the monitoring of immunosuppressive therapies may be warranted. The current study was undertaken to determine if such monitoring is still useful more than 1 yr after heart transplantation. METHODS: Twenty-six patients who had survived the first year after orthotopic heart transplantation and had been on MMF therapy for more than 3 months were prospectively followed. At the time of their routine endomyocardial biopsy blood samples were taken to monitor immunosuppressive therapy. Most patients had two samples taken, on average 109 d apart. RESULTS: There were 22 episodes of asymptomatic rejection documented on a total of 48 biopsies. Of these, only two were of ISHLT (International Society for Heart and Lung Transplantation) grade 3A the remainder being of ISHLT grades 1 or 2. There was no relation between immunosuppressive regimen (tacrolimus and MMF or cyclosporin and MMF) and rejection. There was no relation between monitored immunosuppressive levels and rejection. Patients with the combination of MMF and tacrolimus had significantly higher plasma mycophenolic acid levels despite significantly lower daily MMF dose. CONCLUSION: There does not appear to be a benefit in continued monitoring of plasma mycophenolic acid levels beyond the first year of heart transplantation. There were significant differences in plasma mycophenolic acid levels depending on the type of calcineurin inhibitor concomitantly used. 相似文献
117.
118.
Outcome of sibling vesicoureteral reflux. 总被引:3,自引:0,他引:3
PURPOSE: We determine the efficacy of a prospective screening analysis of an asymptomatic sibling of patients with reflux. MATERIALS AND METHODS: A total of 78 siblings of patients with reflux were evaluated and 40 (51%) had reflux. The resolution rate and necessity for surgical intervention were evaluated. RESULTS: A total of 40 patients had vesicoureteral reflux, including grade I in 12, II in 33, III in 19 and IV in 1. No patient had gross renal scar on ultrasound or renal pelvis dysmorphism on voiding cystourethrogram. Treatment consisted of prophylactic antibiotics in all. One patient required surgical correction for breakthrough urinary tract infection. Followup was available in 31 patients, of whom reflux resolved completely with medical management in 26. Reflux was downgraded in 4 patients. Of the patients in whom reflux resolved completely grades I to II vesicoureteral reflux were in 18, and II to IV in 8. Mean time to resolution was 15.6 months. CONCLUSIONS: The incidence of sibling reflux is significant. However, grade specific time to resolution appears to be decreased compared to primary reflux diagnosed after urinary tract infection. Furthermore, the incidence of renal damage appears to be decreased compared to "traditional" reflux. Although it is reasonable to recommend screening, we suggest that sibling reflux may follow a more benign course. 相似文献
119.
Daly RJ Gu H Parmar J Malaney S Lyons RJ Kairouz R Head DR Henshall SM Neel BG Sutherland RL 《Oncogene》2002,21(33):5175-5181
Grb2-associated binder 2 (Gab2) is a recently identified member of the Gab/Daughter of sevenless family of docking proteins, which localize, amplify and integrate signaling pathways activated by various receptors including receptor tyrosine kinases (RTKs). To date, Gab2 signaling has been primarily investigated in hematopoietic cells. Here we report marked overexpression of Gab2 in a subset of breast cancer cell lines relative to normal breast epithelial strains and a trend for increased Gab2 expression in estrogen receptor (ER)-positive lines. Overexpression relative to normal ductal epithelium was also observed in some primary breast cancers. In MCF-7 breast cancer cells Gab2 was markedly tyrosine phosphorylated in response to heregulin and also following EGF, insulin or bFGF administration, indicating that a variety of RTKs implicated in breast cancer development or progression couple to this docking protein. In hormone-responsive breast cancer cells, GAB2 mRNA and protein expression were induced by estradiol in a manner sensitive to the pure anti-estrogen ICI 182780, indicating that this regulation is mediated via the ER. Gab2 therefore represents a novel link between steroid and growth factor signaling in breast cancer, and when overexpressed, may modulate the sensitivity of breast cancer cells to these important growth regulators. 相似文献
120.
Clinical usefulness of telomerase activation and telomere length in head and neck cancer 总被引:1,自引:0,他引:1
Patel MM Parekh LJ Jha FP Sainger RN Patel JB Patel DD Shah PM Patel PS 《Head & neck》2002,24(12):1060-1067
BACKGROUND: Telomere shortening at every replication cycle is postulated to limit the life span of human somatic cells. In contrast, activation of telomerase is proposed to be an essential step for cancer cell immortalization. Head and neck cancer is the most common malignancy in the Indian population compared with Western countries. However, there are very few reports on telomerase activity and telomere length in head and neck cancer. METHODS: Telomerase activation and telomere length alterations were studied in tumor and adjacent normal tissues in 110 patients with head and neck cancer and 40 patients with precancerous/benign conditions. Telomerase activity and telomere lengths were determined by Telomeric Repeat Amplification Protocol (TRAP assay) and Southern blot analysis, respectively. RESULTS: Telomerase activation was observed in 78.2% of the malignant tissues, 85% of the precancerous tissues, and 53.1% of the adjacent normal tissues. Peak terminal restriction fragment length (TRF) was observed to be significantly lower in malignant tissues compared with the adjacent normal tissues. No significant correlation could be observed between telomerase activation and clinicopathologic characteristics of the patients. Two-year disease-free survival analysis showed that patients showing telomerase activation in the adjacent normal tissues and patients showing higher telomere length in malignant tissues had poor disease-free survival. CONCLUSIONS: Our results demonstrate the significant clinical usefulness of telomerase activation and telomere length for head and neck cancer patients. These markers may be helpful in predicting the clinical course of the disease and thus in identifying the patients in need of a close follow-up and vigorous adjuvant treatment. 相似文献