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   1636篇
  免费   99篇
  国内免费   5篇
耳鼻咽喉   32篇
儿科学   52篇
妇产科学   37篇
基础医学   199篇
口腔科学   41篇
临床医学   86篇
内科学   358篇
皮肤病学   93篇
神经病学   106篇
特种医学   63篇
外科学   270篇
综合类   4篇
一般理论   1篇
预防医学   118篇
眼科学   17篇
药学   85篇
肿瘤学   178篇
  2023年   9篇
  2022年   11篇
  2021年   37篇
  2020年   10篇
  2019年   38篇
  2018年   44篇
  2017年   25篇
  2016年   25篇
  2015年   32篇
  2014年   43篇
  2013年   82篇
  2012年   86篇
  2011年   114篇
  2010年   62篇
  2009年   63篇
  2008年   83篇
  2007年   90篇
  2006年   80篇
  2005年   101篇
  2004年   92篇
  2003年   103篇
  2002年   99篇
  2001年   80篇
  2000年   63篇
  1999年   80篇
  1998年   22篇
  1997年   15篇
  1996年   8篇
  1995年   17篇
  1994年   7篇
  1993年   8篇
  1992年   24篇
  1991年   20篇
  1990年   16篇
  1989年   9篇
  1988年   6篇
  1987年   7篇
  1986年   4篇
  1985年   3篇
  1984年   2篇
  1980年   2篇
  1979年   1篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
  1970年   2篇
  1969年   2篇
  1967年   4篇
  1963年   1篇
排序方式: 共有1740条查询结果,搜索用时 15 毫秒
71.
Early detection and treatment of hemodialysis access dysfunction   总被引:1,自引:0,他引:1  
Purpose: To assess the usefulness of a program for the early detection of hemodialysis graft dysfunction and the impact on graft survival of percutaneous transluminal angioplasty (PTA) and stent implantation to correct venous stenosis. Methods: A program for the early detection of hemodialysis access graft dysfunction was carried out in 110 patients over a period of 80 months. Detection was based on physical examination, flow rate measurements, venous pressure, and analytical determinations performed at dialysis. The stenoses detected were treated by PTA or PTA plus stent deployment. Survival curves compared primary and assisted patency rates for the different graft types. Results: The most important indicators of dysfunction were increased venous pressure and difficulty in cannulation of the graft. Significant stenoses were revealed by 227 (92.2%) of the 246 fistulography procedures performed. PTA results were satisfactory in 100% of the Thomas grafts, 74% of the Brescia-Cimino (BC) grafts, and 53% of the polytetrafluoroethylene (PTFE) grafts. Technical success rates for stent deployment were 92% for BC grafts and 100% for PTFE grafts, while functional success rates were 96% and 97%, respectively. The difference in the primary patency (P1) and assisted patency (AP) values was statistically significant for all three graft types. There was no significant difference in the patency rates for grafts treated by PTA alone or by PTA and stent deployment. Conclusion: A surveillance program helped prevent graft thrombosis, and intervention as required achieved excellent primary and assisted patency rates. Stent deployment salvaged a considerable number of accesses but did not significantly extend access survival time.  相似文献   
72.
High parity, early age at first full-term pregnancy (FTP), and long-term oral contraceptive (OC) use increase cervical cancer risk, but it is unclear whether these variables are also associated with increased risk of acquisition and persistence of human papillomavirus (HPV) infection, the main cause of cervical cancer. Information on reproductive and menstrual characteristics and OC use were collected from 14 areas worldwide, among population-based, age-stratified random samples of women aged 15 years or older. HPV testing was done using PCR-based enzyme immunoassay. Unconditional logistic regression was used to estimate the odds ratios (OR) of being HPV-positive according to reproductive and menstrual factors and corresponding 95% confidence intervals (CI). When more than two groups were compared, floating CIs (FCI) were estimated. A total of 15,145 women (mean age, 40.9 years) were analyzed. Women with >or=5 FTPs (OR, 0.90; 95% FCI, 0.76-1.06) showed a similar risk of being HPV-positive compared with women with only one FTP (OR, 1.00; 95% FCI, 0.86-1.16). However, nulliparous women showed an OR of 1.40 (95% CI, 1.16-1.69) compared with parous women. Early age at first FTP was not significantly related to HPV positivity. HPV positivity was similar for women who reported >or=10 years of use of OCs (OR, 1.16; 95% FCI, 0.85-1.58) and never users of OCs (OR, 1.00; 95% FCI, 0.90-1.12). Our study suggests, therefore, that high parity, early age at first FTP, and long-term OC use are not associated with HPV prevalence, but rather these factors might be involved in the transition from HPV infection to neoplastic cervical lesions.  相似文献   
73.
A 34-year-old male, son of consanguineous parents, had a progressive neurological illness characterized by seizures, tics, choreic movements and mood changes. Acanthocytosis was present in blood. The level of creatine kinase was elevated. Normobetalipoproteinemia was noted. No KX group changes of McLeod syndrome were found. Serial neuroimaging studies demonstrated progressive caudate atrophy. Muscular biopsy confirmed the existence of non-specific myopathy. Genetic study demonstrated homozigosity for the 9q21 region.  相似文献   
74.
75.
Aggressive angiomyxoma of the vulva is a rare entity characterized by local aggressivity and a high recurrence rate after surgical treatment. We report a case of aggressive angiomyxoma of the vulva in a patient diagnosed with Bartholino’s cyst.  相似文献   
76.
Human papillomavirus infection and invasive cervical cancer in Paraguay   总被引:3,自引:0,他引:3  
HPV types 16 and 18 have been categorized as human carcinogens based on their strong associations with cervical cancer in previous case-control studies. Recent IARC studies in the Philippines, Thailand and Morocco show strong associations between invasive cervical cancer and less common HPV types, including HPV 31, 33, 45, 51, 52 and 58. We present results of a further IARC case-control study conducted in Asunción, Paraguay, to examine the association between specific HPV types and invasive cervical cancer as well as risk factors other than HPV. One-hundred thirteen incident histologically confirmed invasive cervical cancer cases and 91 age-matched hospital controls were recruited. A standardized questionnaire was administered to investigate known and suspected risk factors for cervical cancer. For HPV status determination, cervical biopsy specimens from case subjects and exfoliated cervical cells from control subjects were obtained. HPV DNA was ascertained using a GP5+/6+ PCR-based assay capable of detecting more than 33 HPV types. Overall HPV prevalence was 97% in the cervical cancer cases and 20% in the control subjects. As a single infection, HPV 16 was the predominant type with a prevalence of 48% among case subjects and 5.5% among control subjects. Significant associations with the risk of cervical cancer were detected as follows: any HPV type (OR = 114; 95% CI: 36-361); HPV 16 (OR = 910); HPV 18 (infinite OR); HPV 31 (OR = 110); HPV 33 (OR = 261); HPV 45 (OR = 129); and HPV 58 (OR = 36). In the multivariate model, risk factors other than HPV significantly associated with cervical cancer risk were a higher number of lifetime sexual partners, lower educational status and never having had a Pap smear. Strong associations were found between invasive cervical cancer and specific HPV types 16, 18, 31, 33, 45 and 58.  相似文献   
77.
A group of 70 patients with locally advanced non-small-cell lung cancer (LA-NSCLC), treated in different phase II-III trials with platinum-based chemotherapy in two institutions, have been evaluated to identify potential baseline prognostic factors predicting their survival. The eligibility criteria were patients with stage IIIA (N2)-IIIB, Eastern Cooperative Oncology Group performance status 0.1 and less than 5% weight loss. All 37 patients with stage IIIA(N2) were treated with platinum-based induction chemotherapy followed by surgery plus radiotherapy if no progression was observed. The other 33 patients with stage IIIB were treated with platinum-based induction chemotherapy followed by conventional fractionation radiotherapy if no progression was observed. The overall response rate to induction chemotherapy was 40%. Median survival of the 70 patients was 13 months, with a 4-year survival of 15%. At univariate analysis, two prognostic factors correlated with survival: partial or complete response to induction chemotherapy (P<0.00001) and bulky mediastinal lymph nodes (N2>2.5 cm) (P=0.03). At multivariate analysis, only the response to induction chemotherapy retained statistical significance (P=0.00001). Randomized well-balanced prospective trials considering initially mediastinal N2 node size are needed to clearly establish the role of chemotherapy, surgery and radiotherapy in LA-NSCLC.  相似文献   
78.
79.
80.
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