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   6008篇
  免费   380篇
  国内免费   32篇
耳鼻咽喉   62篇
儿科学   138篇
妇产科学   200篇
基础医学   707篇
口腔科学   237篇
临床医学   517篇
内科学   1325篇
皮肤病学   137篇
神经病学   291篇
特种医学   192篇
外国民族医学   4篇
外科学   997篇
综合类   107篇
现状与发展   2篇
一般理论   2篇
预防医学   311篇
眼科学   159篇
药学   649篇
中国医学   41篇
肿瘤学   342篇
  2023年   80篇
  2022年   224篇
  2021年   345篇
  2020年   219篇
  2019年   283篇
  2018年   358篇
  2017年   229篇
  2016年   225篇
  2015年   225篇
  2014年   262篇
  2013年   335篇
  2012年   465篇
  2011年   412篇
  2010年   254篇
  2009年   192篇
  2008年   279篇
  2007年   266篇
  2006年   237篇
  2005年   297篇
  2004年   219篇
  2003年   211篇
  2002年   174篇
  2001年   47篇
  2000年   33篇
  1999年   49篇
  1998年   36篇
  1997年   26篇
  1996年   29篇
  1995年   23篇
  1994年   13篇
  1993年   19篇
  1992年   28篇
  1991年   22篇
  1990年   17篇
  1989年   25篇
  1988年   22篇
  1987年   21篇
  1986年   22篇
  1985年   30篇
  1984年   14篇
  1983年   22篇
  1982年   10篇
  1981年   14篇
  1980年   16篇
  1979年   18篇
  1977年   10篇
  1976年   12篇
  1975年   13篇
  1974年   6篇
  1972年   8篇
排序方式: 共有6420条查询结果,搜索用时 0 毫秒
61.
The response after application of various concentrations of sodium lauryl sulfate (SLS) on human skin is reported. The induced changes associated variable degrees of roughness and erythema characterizing rough dermatitic skin (RDS). These clinical changes were almost invariably (less than 5% experimental error) associated with increased values of transepidermal water loss (TEWL) and increased cutaneous blood flow values (CBFV). A significant positive correlation was found between TEWL and CBFV at all concentrations of SLS. However, values of TEWL higher than those found in 84% of the controls (mean + SD: 8.127 + 2.89 gr/m2/h) were usually significantly correlated with clearcut clinical changes (total clinical score greater than 2 or erythema greater than 1) at all concentrations of SLS, while CBFV (mean + SD of controls: 2.717 + 2.165) which had a wider dispersion, were significantly associated only with erythema after 10% and 1% SLS. This reflects the distinction that is being made between a primary chemical insult, which we identify clinically as roughness and functionally as increased TEWL associated with alterations of barrier function of the skin, and a secondary, delayed inflammatory response, which is clinically recognized as erythema and functionally objectivated by increased CBFV. These results provide a rational basis supporting the use of this experimental model of RDS for testing of preventive and therapeutic efficacy as well as refining the evaluation of tolerance of cosmetics especially designed for use on sensitive skin.  相似文献   
62.
63.
BACKGROUND: Esophageal carcinoma is common in many countries, and it is characterized by poor prognosis and rapid clinical progression with a high frequency of lymph node metastasis and recurrence. The present study was carried out to evaluate the correlation between vascular endothelial cell marker (CD34), matrix metalloproteinase type 9 (MMP9), and DNA content in esophageal carcinoma. METHODS: A total of 38 patients were classified with histopathologic examination as 8 cases with adenocarcinoma, 24 cases with squamous cell carcinoma, and the last 6 cases with undifferentiated carcinoma. The obtained results of the patient group were compared with the results of 6 cases with proven normal esophageal mucosa as a control group. The samples of patients and controls were subjected to immunohistochemical evaluation of CD34 and MMP9 expression along with DNA index determination using flow cytometry. RESULTS: There was a significant difference between patients and normal cases in DNA index, CD34, and MMP9 pattern (P = 0.003, <0.001, and 0.002, respectively). DNA index was positively correlated with MMP9 (r = 0.574, P < 0.001) and with CD34 (r = 0.562, P < 0.001). MMP9 was correlated with CD34 (r = 0.55, P < 0.001). A significant difference was found in both microvessel density and MMP9 expression with respect to tumor grade and stage. The microvessel density in patients with highly positive staining for MMP9 was higher than in those with negative and weak staining for MMP9 (P = 0.002). CONCLUSION: The analysis of DNA content along with detection of CD34 and MMP9 in esophageal cancer can successfully differentiate the different pathologic lesions and hence can be used powerfully in disease prognosis reflecting valuable information about the aggressiveness and activity of those lesions.  相似文献   
64.
The oral cavity has sometimes been described as a mirror that reflects a person''s health. Systemic disease such as diabetes or vitamin deficiency may be seen as alterations in the oral mucosa. A variety of external factors cause changes in the oral mucosa, thus altering mucosal structure and function, and promoting oral pathologies (most frequently bacterial, fungal and viral infections). Little is known, however, about immune surveillance mechanisms that involve the oral mucosa.There is no direct contact between specific immune cells in the basal epithelium and microorganisms in the upper layers of the oral mucosa. The author''s hypothesis is that the protective immunity is conveyed through epithelial cells. The present brief review assesses the oral mucosa''s role as the main defense in the interactions between the host and the oral microbial community. A unique model was used to investigate these interactions as the cause of oral disease and to develop new treatments that exploit our knowledge of the host-microorganism relationship.Key Words: Epithelial cells, Fibroblasts, Oral mucosa, Oral pathologies, Tissue engineering  相似文献   
65.
66.
67.
68.
Renal cell carcinoma (RCC) is the most common renal malignancy in adults and exhibits highly intrinsic and acquired resistance to standard therapeutic strategies. We sought to determine the anti-cancer activity of hydroalcoholic extract of Nigella sativa seeds (NSE) and thymoquinone (TQ). Human renal cell carcinoma (ACHN) and fibroblast L929 cell lines were treated with NSE and TQ, and cytotoxicity was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay. Cell death pattern was determined by annexin V and propidium iodine (PI)-staining methods. Exposure to NSE, TQ and cisplatin significantly inhibited the growth of ACHN cells and showed significant increase of early apoptotic cells. Normal cells were more resistant to NSE and TQ-induced effects. The present study demonstrates that N. sativa and TQ exert anti-proliferative and pro-apoptotic effects on ACHN cells in a concentration and time-dependent manner, which suggests their potential to be used as a new therapeutic strategy for renal cancers.  相似文献   
69.
The aim of this study was to evaluate the use of different fixatives on the reliability of histopathological changes in a rabbit model of proliferative vitreoretinopathy (PVR). Twenty eyes from 10 rabbits were divided into four groups. The right eyes were used in two experimental groups (each n = 5), and the left, in two control groups (each n = 5). Using a newly developed scleral incision marker, an oblique scleral incision was standardized in the experimental groups, followed by intravitreal injection of 0.4 ml autologous blood and the left for wound repair for four weeks. Eyes were enucleated at four weeks. The groups differed in the type of used fixative solution (formaldehyde 4% vs. 1% buffered formaldehyde and 1.25% glutaraldehyde). The eyes were evaluated for the development of fibrosis, retinal detachment (RD), and processed for histopathology. Fibrous ingrowth of a variable degree was present in the experimental groups originating from the trauma site. Experimental eyes fixed with formaldehyde 4% had RD extension that was greater than that fixed in formaldehyde/glutaraldehyde mixture; however, the difference did not reach statistical significance (P = 0.15). This difference was not fully explained by the fibrosis which developed. In addition, in control groups, formaldehyde 4% induced a fixative-dependent retinal separation that was absent in eyes fixed with formaldehyde/glutaraldehyde mixture (P = 0.03). In conclusion, a mixture of buffered formaldehyde 1% and glutaraldehyde 1.25% combined with standardized scleral incision resulted in consistent pathological changes. A reliable PVR model is a condition sine qua non to evaluate antifibrotic treatment strategies.  相似文献   
70.
Background The impact of isolated diastolic dysfunction (IDD) and systolic dysfunction (SD) on health-related quality of life (HRQOL) is unknown. Methods and Results To evaluate HRQOL in patients with IDD and SD under treatment, information on outpatients aged 60-84 years was extracted from the records of 4,500 consecutive individuals who underwent echocardiographic examination at Sado General Hospital. The medical records of these patients were reviewed and a questionnaire, including the Medical Outcome Study Short Form 36, was mailed to 71 IDD and 99 SD patients; answers were obtained from 66 and 91 patients, respectively. The HRQOL of patients with cardiac dysfunction was impaired even when echocardiographic parameters improved with treatment. Patients with IDD showed an impairment of HRQOL similar to those with SD. Compared with males, female patients had a larger and more significant reduction in the physical and mental components of the HRQOL score. These scores correlated positively with exercise capacity in patients with IDD or SD. Conclusions Impaired HRQOL, in both its mental and physical components, is a serious problem for IDD and SD patients under treatment. Because exercise intolerance may underlie the reduced HRQOL, improving exercise capacity could be an important target for managing outpatients with heart failure. (Circ J 2008; 72: 1436 - 1442).  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