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   7914篇
  免费   634篇
  国内免费   50篇
耳鼻咽喉   73篇
儿科学   384篇
妇产科学   190篇
基础医学   983篇
口腔科学   158篇
临床医学   749篇
内科学   1866篇
皮肤病学   80篇
神经病学   912篇
特种医学   375篇
外科学   818篇
综合类   145篇
一般理论   2篇
预防医学   872篇
眼科学   138篇
药学   298篇
中国医学   1篇
肿瘤学   554篇
  2021年   78篇
  2019年   66篇
  2018年   107篇
  2017年   89篇
  2016年   78篇
  2015年   105篇
  2014年   153篇
  2013年   226篇
  2012年   310篇
  2011年   291篇
  2010年   222篇
  2009年   218篇
  2008年   318篇
  2007年   318篇
  2006年   304篇
  2005年   314篇
  2004年   274篇
  2003年   324篇
  2002年   283篇
  2001年   269篇
  2000年   275篇
  1999年   250篇
  1998年   126篇
  1997年   127篇
  1996年   112篇
  1995年   98篇
  1994年   98篇
  1993年   96篇
  1992年   226篇
  1991年   229篇
  1990年   202篇
  1989年   185篇
  1988年   199篇
  1987年   180篇
  1986年   146篇
  1985年   187篇
  1984年   114篇
  1983年   84篇
  1982年   69篇
  1981年   72篇
  1979年   124篇
  1978年   93篇
  1977年   58篇
  1976年   72篇
  1975年   63篇
  1974年   72篇
  1973年   58篇
  1972年   71篇
  1970年   48篇
  1966年   52篇
排序方式: 共有8598条查询结果,搜索用时 15 毫秒
11.
12.
Sixty-seven patients with advanced carcinoma of the lower female genital tract (cervix, vagina, and vulva) were treated with radiation and concomitant intravenous cisplatin and/or 5-fluorouracil. Fifty-seven patients (85%) responded completely clinically. Thirty-five (61%) complete responders recurred with a median time to recurrence of 6 months. Twenty-six of the thirty-five patients who recurred had some component of local failure. The 22 complete responders who have not recurred have been followed a median of 13 months. Acute toxicity was minimal, with only 6 patients requiring interruption of therapy. Nine (13%) patients developed severe late complications and eight required surgery. The actuarial 5-year survival is 22%. This treatment regimen is disappointing in terms of both survival and local control.  相似文献   
13.
Five patients, ages 12 to 20 years, with nonresectable primary (Patients 2, 3, and 5) and metastatic (Patients 1 and 4) pelvic osteosarcomas were treated with intraarterial cisplatin and concurrent radiation therapy from 1983 to 1987. Long-term local tumor control was achieved in all five patients. Patients 1 and 3 are alive with no evidence of local recurrence or metastatic disease at 77 and 56 months of follow-up, respectively, since diagnosis of the pelvic tumor. Patients 2, 4, and 5 died of metastatic lung disease at 25, 39, and 12 months, respectively, after diagnosis of the pelvic tumor. Patient 4 had no clinical or radiologic evidence of local recurrence. Control of tumor growth in patients with pelvic osteosarcomas can be achieved with regional chemotherapy and concurrent radiation therapy. These patients also should receive adjuvant intensive systemic chemotherapy to increase the probability of eliminating potential subclinical metastatic disease.  相似文献   
14.
BACKGROUND: Basal cell carcinoma shows a wide spectrum of clinical and histologic appearances. A distinct tumor variant with follicular infundibulocystic differentiation is recognized, and there are only a few reports on its clinical presentation and management. OBJECTIVE: To report a case of multiple infundibulocystic basal cell carcinomas with a unique unilateral presentation. METHODS: A clinical history was obtained. Photographs were taken, and punch biopsies were performed. RESULTS: An 83-year-old Caucasian female presented with multiple unilateral, asymptomatic, skin-colored, dome-shaped papules around the right mouth for 11 years without apparent change. Punch biopsies revealed findings typical of infundibulocystic basal cell carcinoma. CONCLUSIONS: A patient with clinically indolent multiple unilateral infundibulocystic basal cell carcinomas is described. Given the location of these multiple lesions, standard treatment modalities for basal cell carcinomas would have significant cosmetic and functional implications. A management approach with clinical follow-up and surgical intervention only for changing lesions is discussed.  相似文献   
15.
We examined the relative role of the natural killer (NK) cell and H-ras gene in controlling metastasis formation using a novel assay for quantitating viable tumor cells entering and surviving in the lung for up to 13 days following i.v. tumor inoculation. This assay utilized the resistance to G418 sulfate conferred by transfection of the neoR gene into 10T1/2 fibroblasts along with activated H-ras. We had previously shown that the metastatic efficiency of T-24-H-ras-transformed 10T1/2 fibroblasts correlated with H-ras expression at the RNA level. In this paper we show that the NK cell could recognize H-ras-transformed fibroblasts in vivo and control experimental metastasis formation using NK-suppressed and -activated syngeneic C3H recipients. Evaluation of NK sensitivity in vitro of individual lines did not predict metastatic ability. However, NK susceptibility in vitro did inversely correlate with the ability of tumor cells to arrest and survive in the lung for the first 48 h after i.v. inoculation. Although the level of H-ras RNA correlated with the ultimate metastatic potential, it did not correlate with the initial rate of tumor cell pulmonary retention or clearing. Over the next 10 to 12 days, however, we detected a preferential survival and outgrowth of high H-ras-expressing variants, which correlated well with the ultimate metastatic ability but not NK susceptibility. These observations argue that the NK cell has its major effect early in the course of the disease, while subsequent tumor growth occurs preferentially in high H-ras-expressing cell lines.  相似文献   
16.
In July 1986, a provisional clinical case definition of AIDS in children, developed by the World Health Organization (WHO) for surveillance purposes in Africa, was tested on 159 patients hospitalized in the Department of Pediatrics at Mama Yemo Hospital, Kinshasa, Zaire. Twenty-one (13%) of these children were seropositive for HIV. In this population, the clinical case definition of pediatric AIDS was found to be fairly specific (87%) but lacked sensitivity (35%). The positive predictive value for HIV seropositivity was 25%. This study suggests that it is more difficult to define AIDS clinically in children than in adults and that the utility of the proposed WHO clinical case definition for pediatric AIDS for surveillance of children's AIDS in Africa is limited.  相似文献   
17.
本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4~5.6%,血浓69.6~1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。  相似文献   
18.
The Assessment of Living Skills and Resources (ALSAR), an innovative instrumental activities of daily living tool, systematically evaluates the accomplishment of 11 tasks by separately rating patient skill and resource levels for each task and combining these levels to determine risk. The ALSAR was administered to 75 elderly veterans in a home care program. It predicted change to more supportive living arrangements and a more structured living environment, nursing home placement, hospitalization, and death during the 6-month study period. The ALSAR has proven useful for interdisciplinary problem solving and treatment planning.  相似文献   
19.
African Americans experienced massive internal migrations that shifted more than 6 million Southern-born blacks to other sections of the United States over the past century, a trend that only recently has been reversed. Whenever mass migration takes place, there is an opportunity to examine the role of the native and relocated environments in the development of disease. This article examines those relationships for diabetes mellitus, a group of diseases that disproportionately affect African-Americans relative to other racial and ethnic groups in the United States. Age-specific and age-adjusted rates with 95% confidence intervals were calculated for males and females for combinations of five regions of birth and four regions of residence at time of death. Southern-born males had statistically significantly higher death rates from diabetes than did their counterparts who died in the same regions in 9 of 16 comparisons. For females, those born in the South had statistically significantly higher rates in 15 of 16 comparisons. The results of this study indicate that place of birth and early life experiences are statistically associated with diabetes mortality among African Americans regardless of place of residence at time of death.  相似文献   
20.
Interstitial pulmonary fibrosis occurs in approximately 9% of patients with PM/DM, yet its effect on the course of PM/DM has been scarcely noted. In this report, two patients with PM/DM and IPF were presented to highlight the fact that pulmonary disease can overshadow the primary muscle disorder and progress despite therapy with corticosteroids and nonsteroidal immunosuppression. Our patients were added to previously reported cases and an overview of PM/DM and IPF was presented. Sixty-seven patients with the diagnosis of PM/DM and IPF, with a mean age of 60 +/- 18 years, were identified. Pulmonary complaints were present in 64 cases. Fever was present in 18, arthritis or arthralgias in 11, and Raynaud's phenomenon in 9. Forty percent died after followup of 31 +/- 32 months. This mortality was significantly higher (P less than .05) than that in 745 historical controls with PM/DM without IPF. Progressive IPF was the immediate cause of death in 58% of those who died. A subgroup of 29 patients who had histologic documentation of both myositis and IPF had a mortality of 62% after 22 +/- 25 months. In this latter group, six patients had RP; five of these died. Patients who were not treated with corticosteroids also appeared to fare worse but, given the small number of patients involved, definite conclusions cannot be drawn. We conclude that patients with PM/DM can be adversely affected by the presence of IPF and that this negative impact may be exaggerated by RP and perhaps by lack of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)  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