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   532篇
  免费   86篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   41篇
妇产科学   11篇
基础医学   69篇
口腔科学   31篇
临床医学   110篇
内科学   117篇
皮肤病学   14篇
神经病学   24篇
特种医学   37篇
外科学   52篇
综合类   15篇
预防医学   43篇
眼科学   10篇
药学   21篇
肿瘤学   27篇
  2024年   2篇
  2023年   11篇
  2021年   8篇
  2020年   5篇
  2019年   4篇
  2018年   17篇
  2017年   15篇
  2016年   10篇
  2015年   12篇
  2014年   19篇
  2013年   25篇
  2012年   7篇
  2011年   13篇
  2010年   22篇
  2009年   36篇
  2008年   19篇
  2007年   12篇
  2006年   11篇
  2005年   14篇
  2004年   12篇
  2003年   10篇
  2002年   10篇
  2001年   7篇
  2000年   7篇
  1999年   21篇
  1998年   23篇
  1997年   38篇
  1996年   37篇
  1995年   29篇
  1994年   21篇
  1993年   18篇
  1992年   4篇
  1991年   6篇
  1990年   7篇
  1989年   16篇
  1988年   8篇
  1987年   5篇
  1986年   11篇
  1985年   12篇
  1984年   8篇
  1983年   6篇
  1982年   10篇
  1981年   6篇
  1980年   10篇
  1978年   4篇
  1977年   3篇
  1976年   5篇
  1970年   1篇
  1969年   2篇
  1966年   1篇
排序方式: 共有623条查询结果,搜索用时 9 毫秒
1.
BACKGROUND: Development of more than one primary melanoma in a patient is a relatively uncommon but well-recognized phenomenon. Its frequency has ranged from 1.2% to 8.2% in several series. This subgroup of patients with multiple primary lesions has not been characterized sufficiently. We report the experience of the Melanoma Unit of University Hospital Spedali Civili of Brescia, Italy. METHOD: Study subjects were drawn from 1240 patients with histologically confirmed melanoma, including melanoma in situ. From this group, multiple melanomas developed in 47 patients (3.79%). Every one of our patients has been taught to perform self-examination of the skin to detect suspicious pigmented lesions. RESULTS: Of the 47 patients described in this study, 38 had two primary melanomas, 7 had three melanomas and 2 had 5 and 10 melanomas, respectively. Mean age at first diagnosis was 46.2 years. The majority of subsequent melanomas (74.5%) were removed within 5 years of the initial operation. Synchronous lesions were found in 10 patients. In male patients, the lesion appeared most frequently on the trunk; in female patients, melanoma appeared mostly on the lower extremities. The second primary melanomas developed in the same anatomic region from the first in 53.2% of our patients. The proportion of in situ to invasive melanomas was greater for the second melanomas compared with the first melanomas. Regarding invasive melanomas, the mean thickness of the first melanomas was 1.31 mm compared with 0.66 mm for the second ones. Dividing patients into two groups, of more and less than 50, it is highlighted that in older patients synchronous lesions appear more frequently (36.4% vs. 8.0%); the median time interval between sequential melanomas is longer (84 vs. 63.7 months); and the ratio between the primary and secondary melanoma mean thickness is lower (1.21 : 1.08 vs. 1.43 : 0.63 mm). CONCLUSIONS: The study confirms that second primary melanoma is usually thinner than the first lesion, and it is more common in the same region of the body as the initial melanoma. The highest risk for a second melanoma is during the first 5 years, but a much longer time interval of 28 years is possible. Continued medical follow-up with complete skin examinations seems prudent, but it is very important to promote self-skin evaluation in patients to detect not only metastases but also subsequent primary melanomas in their earliest phases.  相似文献   
2.
3.
4.
To study complement activation, we evaluated nine patients who underwent cardiac operations requiring cardiopulmonary bypass (CPB) and nine other patients who underwent thoracic vascular operations without CPB. Concentration of C3, as measured by radioimmunoassay, was used as an indicator of complement activation (C3a is a complement-degradation product). In the CPB patients, the C3a level increased tenfold (from baseline value) after the onset of bypass, and continued to increase during bypass. Protamine produced an additional twofold increase in the C3a value, to a peak of 5461 +/- 1360 ng/ml. By 12 hours after surgery, the C3a level had decreased to normal (400 ng/ml). In the non-CPB patients, C3a remained at baseline levels until the administration of protamine, which caused a tenfold increase to a peak of 2281 +/- 293 ng/ml; C3a levels returned to normal 6 hours after operation. The peak postprotamine C3a levels were significantly higher (p < 0.01) in the CPB group than in the non-CPB group. This finding was due to the fact that, during CPB, complement activation occurs via the alternative pathway; the administration of protamine then causes additional activation via the classical pathway. During thoracic vascular operations, however, complement activation occurs only in response to protamine, via the classical pathway.  相似文献   
5.
6.
7.
8.
9.
OBJECTIVES: To explore patient views on participation in treatment, physical care and psychological care decisions and factors that facilitate and hinder patients from making decisions. DESIGN: Qualitative study using semi-structured interviews with patients. SETTING AND PARTICIPANTS: Three NHS Trusts in the north-west of England. Theoretical sampling including 41 patients who had been treated for colorectal cancer. RESULTS: For patients, participation in the decision-making process was about being informed and feeling involved in the consultation process, whether patients actually made decisions or not. The perceived availability of treatment choices (surgery, radiotherapy, chemotherapy) was related to type of treatment. Factors that impacted on whether patients wanted to make decisions included a lack of information, a lack of medical knowledge and trust in medical expertise. Patients perceived that they could have a more participatory role in decisions related to physical and psychological care. CONCLUSION: This study has implications for health professionals aiming to implement policy guidelines that promote patient participation and shared partnerships. Patients in this study wanted to be well informed and involved in the consultation process but did not necessarily want to use the information they received to make decisions. The presentation of choices and preferences for participation may be context specific and it cannot be assumed that patients who do not want to make decisions about one aspect of their care and treatment do not want to make decisions about other aspects of their care and treatment.  相似文献   
10.
Aim: The purpose of this study was to assess objectively the ultrastructure of the secretory granules in rabbit conjunctival mucin‐producing ‘goblet’ cells. Method: The upper eyelids from five young adult dioestrous female rabbits were dissected out, stretched onto a cardboard support and prepared for transmission electron microscopy by repeated application of an isotonic two per cent glutaraldehyde fixative at room temperature. Post‐fixation treatment included osmium tetroxide and staining with uranyl acetate and lead citrate. Low magnification micrographs were taken of the goblet cells of the conjunctiva, printed at a magnification of approximately 6,000 and the number, size and features of the secretory granules assessed. Results: Across the entire palpebral conjunctiva of ail five rabbits, the majority of mucous cells displayed a goblet shape and the secretory granules were uniformly pale in staining. The average width of the goblet cells was 10.8 ± 1.1 μm and the diameter of the secretory granules was 0.82 ± 0.16 μm. However, in localised regions across the palpebral conjunctiva of two of the rabbits, some goblet cells were different in that the secretory granules had either a denser‐staining core, in which some of the granules were densely staining (while others were pale) or most of the granules were densely staining. These mucous cells had an average diameter of 10.3 ± 1.7 μm and the granule diameters averaged 0.88 ± 0.01 μm. For these abnormal goblet cells, inflammatory cells were found in their immediate vicinity. Occasionally, goblet cells were seen to be in the process of degranulation with associated apparent cell necrosis and the mucin granule diameter was close to 1 μm. Conclusions: The ultrastructure of the mucin‐containing secretory granules of the conjunctival mucous cells is not necessarily homogeneous in character and further attention needs to be given to the effects of localised inflammation in the tissue and to possible hormonal influences.  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