全文获取类型
收费全文 | 2147篇 |
免费 | 207篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 63篇 |
妇产科学 | 46篇 |
基础医学 | 382篇 |
口腔科学 | 26篇 |
临床医学 | 246篇 |
内科学 | 306篇 |
皮肤病学 | 16篇 |
神经病学 | 166篇 |
特种医学 | 213篇 |
外科学 | 254篇 |
综合类 | 92篇 |
一般理论 | 2篇 |
预防医学 | 140篇 |
眼科学 | 23篇 |
药学 | 122篇 |
中国医学 | 4篇 |
肿瘤学 | 208篇 |
出版年
2021年 | 17篇 |
2020年 | 17篇 |
2019年 | 20篇 |
2018年 | 23篇 |
2017年 | 16篇 |
2016年 | 24篇 |
2015年 | 38篇 |
2014年 | 52篇 |
2013年 | 89篇 |
2012年 | 73篇 |
2011年 | 77篇 |
2010年 | 56篇 |
2009年 | 65篇 |
2008年 | 87篇 |
2007年 | 81篇 |
2006年 | 93篇 |
2005年 | 87篇 |
2004年 | 68篇 |
2003年 | 73篇 |
2002年 | 66篇 |
2001年 | 64篇 |
2000年 | 74篇 |
1999年 | 59篇 |
1998年 | 59篇 |
1997年 | 53篇 |
1996年 | 41篇 |
1995年 | 43篇 |
1994年 | 26篇 |
1993年 | 34篇 |
1992年 | 54篇 |
1991年 | 59篇 |
1990年 | 53篇 |
1989年 | 41篇 |
1988年 | 58篇 |
1987年 | 44篇 |
1986年 | 43篇 |
1985年 | 44篇 |
1984年 | 33篇 |
1983年 | 14篇 |
1982年 | 25篇 |
1981年 | 20篇 |
1980年 | 24篇 |
1979年 | 19篇 |
1978年 | 16篇 |
1977年 | 20篇 |
1976年 | 13篇 |
1975年 | 12篇 |
1974年 | 18篇 |
1973年 | 16篇 |
1968年 | 10篇 |
排序方式: 共有2367条查询结果,搜索用时 781 毫秒
1.
2.
3.
4.
5.
Dr. S. Eggstein MD G. Manthey MT T. Hirsch PhD F. Baas MA B. U. V. Specht MD E. H. Farthmann MD 《Digestive diseases and sciences》1996,41(6):1069-1075
Epidermal growth factor receptors (EGFR) andras mutations are known to play a significant role in controlling cell growth and tumor promotion. Both of them transmit mitogenic signals to the nucleus by activation of Raf-1 kinase. In this study, the expression of EGFR and mutant Ras proteins, and, for the first time, the expression, phosphorylation and kinase activity of Raf-1 kinase have been determined in paired samples of colorectal cancer and mucosa. The tumor and mucosa samples did not differ significantly with regard to Raf-1 kinase content and activity. A major difference between tumors and mucosa was found, however, in the phosphorylation of Raf-1. Most of the mucosa samples (13/20), but only 1/20 of the cancer samples, contained hyperphosphorylated Raf-1. EGFR were significantly (p=0.0025) decreased in the tumors. The decreased phosphorylation of Raf-1 in colonic carcinomas could be the result of activation of Raf-1 phosphatases or inactivation of kinases phosphorylating Raf-1. New forms of treatment based on EGFR overexpression do not seem to be suitable for the majority of colonic cancers.This work was supported by the state of Baden-Württemberg (Verbundforschungsprojekt: Aufklärung von Mechanismen der Tumorentstehung und Tumorabwehr). 相似文献
6.
7.
Ohne Zusammenfassung 相似文献
8.
9.
Trine Juhler N?ttrup Stine Sofia Korreman Anders Navrsted Pedersen Lasse Rye Aarup H?kan Nystr?m Mikael Olsen Lena Specht 《Radiotherapy and oncology》2007,84(1):40-48
BACKGROUND AND PURPOSE: This study aimed at quantifying the breathing variations among lung cancer patients over full courses of fractionated radiotherapy. The intention was to relate these variations to the margins assigned to lung tumours, to account for respiratory motion, in fractionated radiotherapy. MATERIALS AND METHODS: Eleven lung cancer patients were included in the study. The patients' chest wall motions were monitored as a surrogate measure for breathing motion during each fraction of radiotherapy by use of an external optical marker. The exhale level variations were evaluated with respect to exhale points and fraction-baseline, defined for intra- and interfraction variations respectively. The breathing amplitude was evaluated as breathing cycle amplitudes and fraction-max-amplitudes defined for intra- and interfraction breathing, respectively. RESULTS: The breathing variations over a full treatment course, including both intra- and interfraction variations, were 15.2mm (median over the patient population), range 5.5-26.7mm, with the variations in exhale level as the major contributing factor. The median interfraction span in exhale level was 14.8mm, whereas the median fraction-max-amplitude was 6.1mm (median of patient individual SD 1.4). The median intrafraction span in exhale level was 1.6mm, and the median breathing cycle amplitude was 4.0mm (median of patient individual SD 1.4). CONCLUSIONS: The variations in externally measured exhale levels are larger than variations in breathing amplitude. The interfraction variations in exhale level are in general are up to 10 times larger than intrafraction variations. Margins to account for respiratory motion cannot safely be based on one planning session, especially not if relying on measuring external marker motion. Margins for lung tumours should include interfraction variations in breathing. 相似文献
10.
T J Whelan A J Dembo R S Bush J F Sturgeon S Fine J F Pringle G A Rawlings G M Thomas J Simm 《International journal of radiation oncology, biology, physics》1992,22(5):853-858
We examined the records of 105 patients with advanced ovarian cancer who had been treated with cisplatin combination chemotherapy followed by abdominopelvic radiotherapy. The purpose was to define the morbidity of this approach, and identify those factors predictive of toxicity. Acute toxicity resulting in delay or failure to complete treatment was most commonly due to myelosuppression. Nine of 105 patients (8.6%) required surgery for bowel obstruction that was not due to recurrent disease, 3 had an episode of bowel obstruction that settled conservatively, and a further 5 underwent surgery for obstruction due to recurrent tumor. The presence of both a dose of abdominopelvic radiotherapy over 2250 cGy, as well as a second-look laparotomy prior to radiotherapy, was associated with an increased risk of serious bowel complications. The increased frequency of late bowel morbidity seen in the combined modality group is likely explained by the presence of these two factors, rather than the exposure to chemotherapeutic agents per se. These observations are supported by the published literature. 相似文献