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   1809篇
  免费   105篇
  国内免费   14篇
耳鼻咽喉   20篇
儿科学   123篇
妇产科学   96篇
基础医学   199篇
口腔科学   110篇
临床医学   120篇
内科学   327篇
皮肤病学   41篇
神经病学   130篇
特种医学   65篇
外科学   245篇
综合类   33篇
预防医学   65篇
眼科学   124篇
药学   67篇
中国医学   6篇
肿瘤学   157篇
  2023年   16篇
  2022年   26篇
  2021年   48篇
  2020年   35篇
  2019年   36篇
  2018年   50篇
  2017年   38篇
  2016年   59篇
  2015年   71篇
  2014年   84篇
  2013年   108篇
  2012年   158篇
  2011年   134篇
  2010年   74篇
  2009年   75篇
  2008年   138篇
  2007年   142篇
  2006年   138篇
  2005年   127篇
  2004年   107篇
  2003年   82篇
  2002年   72篇
  2001年   26篇
  2000年   14篇
  1999年   14篇
  1998年   5篇
  1997年   1篇
  1996年   7篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   11篇
  1991年   4篇
  1990年   7篇
  1989年   2篇
  1988年   1篇
  1986年   2篇
  1985年   2篇
  1983年   2篇
  1980年   1篇
  1979年   2篇
  1975年   1篇
  1971年   1篇
  1970年   1篇
  1967年   1篇
排序方式: 共有1928条查询结果,搜索用时 15 毫秒
91.
92.
93.
The study of mitotic transduction of the signal showed that overexpression of pAkt and reduction in pERK expression would be associated a biological relapse. For tumors T1-3 N0M0 at the high risk of local relapse after prostatectomy, an immediate radiotherapy compared with a differed radiotherapy (at the time of PSA relapse), showed a significant reduction in the rate of local relapse and an ameliorated progression free survival. The effectiveness of the docetaxel was confirmed in two phase III randomized clinical trials : TAX-327 with 3 arms compared docetaxel every 21 days, docetaxel every 7 days and mitoxantrone. All arms were prednisone-based. An increase in overall survival, PSA progression free survival, PSA response rate and a pain reduction were highlighted in the docetaxel arm every 21 days. Docetaxel obtained at the end of this study the marketing authorization in this indication and became the treatment of reference. The SWOG 99-16 study compared the docetaxel estramustine association with the same arm of reference, mitoxantrone and prednisone, with similar results. The addition of estramustine to the docetaxel seems to improve the PSA response rate and progression free survival, but with a greater embolic toxicity. The addition of an antiangiogenic agent, the thalidomide, to docetaxel, improves progression free survival and overall survival. PSA responses were observed with an inhibitor of the proteasome, the bortezomib, in monotherapy, contrary to the imatinib which in monotherapy didn't have any effectiveness. Studies in association with docetaxel are ongoing. Some biological responses were observed with a vaccine anti MUC-1 and must be confirmed on a greater series of patients. The docetaxel impact on localized disease is actually evaluated.  相似文献   
94.
95.
Nitric oxide (NO) is an important messenger molecule with a wide range of actions in virtually all cell systems and organs. In kidneys it participates in glomerular and medullary hemodynamics, tubuloglomerular feed-back, renin secretion, and extracellular fluid balance. Although the role of NO in regulating renal function in adults is well-established, it has recently been suggested that NO has a more critical role in maintaining basal renal blood flow and glomerular filtration rate (GFR) in the developing kidney. NO is rapidly metabolized to the stable end products nitrite and nitrate, which are more slowly excreted into the urine. Thus these metabolites can be recommended as useful markers of endogenous NO synthase activity, despite limited data about age-related changes in in-vivo NO production. The aims of this study were to determine age-related normal reference values of serum and urinary NO metabolites and to assess the probable relationship between these metabolites and the GFR. Normal levels of NO end products in blood and urine of 296 healthy children (117 female, 179 male) between the ages of 0 and 16 were investigated, as was whether these values change with age. Serum and urinary nitrate levels did not differ according to sex. Serum nitrate levels are higher in younger children, especially in the newborn period, and decrease with age. Nitrate levels in urine are higher in younger children with a peak in infancy (1 month to 1 year) and decrease with age. It was demonstrated that this decrease in serum and urinary nitrate levels with age parallels the increase in GFR. In conclusion, urinary NO products may be an indirect marker of serum NO levels and NO might have an important regulatory function both in the maintenance of renal function and in the maturation of the developing kidneys.  相似文献   
96.
Comparison of Prosthetic Materials in Incisional Hernia Repair   总被引:5,自引:0,他引:5  
Purpose Incisional hernias are not uncommon after abdominal surgery, but their repair is associated with a high risk of complications, including adhesions and recurrence. Many different types of meshes and adhesion barriers have been developed in an attempt to overcome these problems, some of which we have assessed in a rat model.Methods We made a full-thickness 1.5 × 2.5-cm abdominal wall defect in 30 Sprague-Dawley rats, which were divided into three groups according to the materials used for repair: 2 × 3-cm polypropylene mesh (group 1); expanded polytetrafluoroethylene (PTFE) with double-layer polypropylene mesh (group 2); or polypropylene mesh with oxidized cellulose adhesion barriers (group 3). We assessed adhesion formation, tensile strength, and histopathologic findings.Results The mean adhesion scores were 3.3, 1.3, and 0.7, in groups 1, 2, and 3, respectively (P < 0.001). The area involved by adhesions was significantly greater in group 1 than in groups 2 or 3 (P < 0.01, P < 0.05), but there was no significant difference between groups 2 and 3 (P < 0.05). The tensile strength in group 2 was less than that in groups 1 or 3 (P < 0.01, P < 0.05), but there was no significant difference between groups 1 and 3 (P > 0.05).Conclusion Although there was less adhesion formation with PTFE and oxidized cellulose, PTFE not only impaired the tensile strength, but also induced fibrosis and inflammation. An oxidized cellulose adhesion barrier can be safely used in incisional hernia repair to prevent intra-abdominal adhesions.  相似文献   
97.
We compared early-onset and late-onset obsessive-compulsive disorder (OCD) patients in terms of demographic and clinical features. One hundred sixteen outpatients whose primary diagnosis was OCD according to DSM-IV diagnostic criteria were recruited. Early-onset (n=50) and late-onset (n=66) OCD groups were compared with respect to demographic variables and scores obtained on various scales. A male gender predominance was found in early-onset OCD group. Symmetry/exactness obsessions, religious obsessions, hoarding/saving obsessions, and hoarding/collecting compulsions also were significantly more frequent in the early-onset group than in the late-onset group. The results may suggest a phenotypic difference between the two groups. Further studies are needed to investigate the differences between early-onset and late-onset OCD groups to examine the hypothesis that early-onset OCD is a distinct subtype of the disorder.  相似文献   
98.
99.
OBJECTIVES: The aim of this study was to evaluate the significance of p53 expression and proliferative activity of glandular epithelium and intestinal metaplasia in Helicobacter pylori associated gastritis of pediatric patients. METHODS: The study included endoscopic gastric biopsies of 54 children with dyspeptic complaints. Immunohistochemistry was performed for evaluation of p53 expression and Ki-67 labeling index, an indicator of proliferative activity. Grading of H. pylori density, intestinal metaplasia and inflammatory cell infiltration were performed in histologic tissue sections stained with hematoxylin-eosin, Giemsa and Alcian-blue. RESULTS: Of 54 children, 35 (64%) were infected by H. pylori. Positive immunostaining for p53 was observed in 11 of 54 cases (20.4%). H. pylori infection was found in 10 (91%) of the p53-positive patients. There was a positive correlation between H. pylori density and Ki-67 labeling index in H. pylori infected children. H. pylori density, Ki-67 labeling index and inflammatory cell infiltration in the p53-positive group were significantly higher than in the p53-negative group. Although intestinal metaplasia was more common in H. pylori infected children (n = 11; 31.4%), there was no difference in the rate of intestinal metaplasia between the p53-positive and p53-negative groups. CONCLUSIONS: The present study shows that p53 mutations and higher proliferative activity of glandular epithelium may be related to H. pylori associated gastritis in children. Because p53 mutation does not appear to be associated with intestinal metaplasia, a precursor for gastric cancer in adults, we think that H.pylori associated p53 alterations do not initiate and promote gastric cancer that may occur in adulthood.  相似文献   
100.
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