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   3948篇
  免费   227篇
  国内免费   120篇
耳鼻咽喉   28篇
儿科学   116篇
妇产科学   41篇
基础医学   530篇
口腔科学   417篇
临床医学   362篇
内科学   812篇
皮肤病学   161篇
神经病学   177篇
特种医学   415篇
外国民族医学   1篇
外科学   420篇
综合类   43篇
一般理论   1篇
预防医学   319篇
眼科学   69篇
药学   194篇
中国医学   12篇
肿瘤学   177篇
  2023年   31篇
  2022年   53篇
  2021年   97篇
  2020年   81篇
  2019年   93篇
  2018年   129篇
  2017年   79篇
  2016年   89篇
  2015年   106篇
  2014年   146篇
  2013年   195篇
  2012年   275篇
  2011年   245篇
  2010年   182篇
  2009年   174篇
  2008年   187篇
  2007年   243篇
  2006年   174篇
  2005年   166篇
  2004年   105篇
  2003年   89篇
  2002年   75篇
  2001年   62篇
  2000年   62篇
  1999年   54篇
  1998年   102篇
  1997年   97篇
  1996年   112篇
  1995年   71篇
  1994年   66篇
  1993年   72篇
  1992年   30篇
  1991年   42篇
  1990年   32篇
  1989年   52篇
  1988年   45篇
  1987年   53篇
  1986年   38篇
  1985年   51篇
  1984年   21篇
  1983年   19篇
  1982年   26篇
  1981年   22篇
  1980年   31篇
  1979年   11篇
  1978年   13篇
  1977年   19篇
  1976年   29篇
  1975年   15篇
  1969年   9篇
排序方式: 共有4295条查询结果,搜索用时 15 毫秒
61.
BACKGROUND & AIMS: Interleukin (IL)-1 gene cluster proinflammatory polymorphisms have been associated with development of gastric atrophy and with increased risk of gastric carcinoma. We aimed to determine the association between IL-1 loci polymorphisms and increased risk of gastric carcinoma in samples from a Portuguese population, and to find whether there was any relationship with the histologic types of gastric carcinoma. METHODS: In a case-control study including 220 controls and 152 patients with gastric carcinoma (intestinal, 76; diffuse, 37; and atypical, 39), both the IL-1B-511 biallelic polymorphism and the IL-1RN penta-allelic variable number of tandem repeats were genotyped. RESULTS: We found a significant association between the IL-1 polymorphisms and increased risk for tumor development in patients with intestinal-type gastric carcinoma. A trend towards an increased risk of tumor development was also observed in patients with diffuse-type gastric carcinoma. No significant relationship was observed in patients with atypical carcinoma. Carriers of IL-1B-511T and IL-1RN*2 homozygotes had increased risk for developing intestinal-type gastric carcinoma with odds ratios of 2.7 (95% confidence interval [CI], 1.5-4.9) and 3.1 (95% CI, 1.5-6.5), respectively. Statistical analysis showed an interaction between the 2 loci with the risk conferred by the IL-1B-511T allele substantially increased (odds ratio, 9.0; 95% CI, 3.5-23.0) in individuals homozygous for the IL-1RN*2 allele. CONCLUSIONS: Our results provide further support to the association between IL-1 gene cluster proinflammatory polymorphisms and increased risk of gastric carcinoma. Furthermore, we found evidence pointing to the existence of a synergistic interaction between the IL-1B and IL-1RN polymorphisms.  相似文献   
62.
Moderation of hemophilia A phenotype by the factor V R506Q mutation   总被引:11,自引:1,他引:11  
Although many examples of unrelated hemophilia A patients carrying identical point mutations in the factor VIII (FVIII) gene have been reported, the clinical phenotype is not always the same among patients sharing the same molecular defect. Possible explanations for this discrepancy include undetected additional mutations in the FVIII gene or coinheritance of mutations at other genetic loci that modulate FVIII function. We report molecular genetic analysis of potential modifying genes in two sets of unrelated patients carrying common FVIII missense mutations but exhibiting different levels of clinical severity. Both mutations (FVIII R1689C and R2209Q) are associated with severe hemophilia A in some patients and mild/moderate disease in others. The common von Willebrand disease type 2N mutation (R91Q) was excluded as a modifying factor in these groups of patients. However, analysis of the recently described factor V (FV) R506Q mutation (leading to activated protein C resistance) identified a correlation of inheritance of this defect with reduced hemophilia A severity. Two moderately affected hemophilia A patients, each with either of two FVIII gene mutations, were heterozygous for FV R506Q, whereas two severely affected patients and two moderately affected patients were homozygous normal at the FV locus. Our results suggest that coinheritance of the FV R506Q mutation may be an important determinant of clinical phenotype in hemophilia A and that modification of the protein C pathway may offer a new strategy for the treatment of FVIII deficiency.  相似文献   
63.
Linker  CA; Ries  CA; Damon  LE; Rugo  HS; Wolf  JL 《Blood》1993,81(2):311-318
We have studied the use of a new preparative regimen for the treatment of patients in remission of acute myeloid leukemia (AML) with autologous bone marrow transplantation. Chemotherapy consisted of busulfan 1 mg/kg every 6 hours for 4 days (total dose, 16 mg/kg) on days -7 through -4 followed by an intravenous infusion over 6 to 10 hours of etoposide 60 mg/kg on day -3. Autologous bone marrow, treated in vitro with 100 micrograms/mL of 4-hydroperoxycyclophosphamide, was infused on day 0. We have treated 58 patients up to the age of 60 years, 32 in first remission, 21 in second or third remission, and 5 with primary refractory AML unresponsive to high-dose Ara-C, but achieving remission with aggressive salvage regimens. Of the first remission patients, there has been 1 treatment related death and 5 relapses. With median follow-up of 22 months, the actuarial relapse rate is 22% +/- 9% and disease-free survival is 76% +/- 9% at 3 years. Patients with favorable French-American-British (FAB) subtypes (M3 or M4 EO) did especially well, with no relapses seen in 15 patients observed for a median of 30 months. Actuarial relapse rate at 3 years was 48% for first remission patients with less favorable FAB subtypes. Of patients in second or third remission, there were 5 treatment related deaths and 4 relapses. With median follow-up of 22 months, the actuarial relapse rate is 25% +/- 11% and disease-free survival is 56% +/- 11% at 3 years. Four of five primary refractory patients died during treatment and 1 remains in remission with short follow-up. These preliminary data are very encouraging and, if confirmed, support the use of autologous purged bone marrow transplantation using aggressive preparative regimens as one approach to improve the outcome of adults with AML.  相似文献   
64.
65.
66.
67.
68.
69.
Objectives: The present investigation aimed to assess the bone‐regenerative potential of two formulations of anorganic bovine‐derived mineral bound to a P‐15 (ABM/P‐15) bone graft – the particulate and the hydrogel forms – in a delayed healing rabbit cranial defect model. Material and methods: Ten adult male New Zealand White rabbits were used to create two 8 mm transcortical cranial defects per rabbit and each one received randomly the test material (ABM/P‐15 carboxymethyl cellulose (CMC)‐hydrogel graft), the standard control material (ABM/P‐15 particulate graft) or remained empty as a negative control. The defects were allowed to heal for 2 and 4 weeks. Qualitative and quantitative histological outcomes were assessed on undecalcified sections. Results: In the defects grafted with the test material, at both time points, there was a marked random migration of the bone substitute particles. As a consequence, the space maintenance provision was lost and new bone formation was reduced compared with the control particulate graft material. The histomorphometric analysis showed that the control material attained better results, with an average of 13.8 ± 1.9% and 18.2 ± 4.4% of new bone at 2 and 4 weeks, compared with 8.5 ± 2.4% and 13 ± 2.9% for the test material. These differences were significant at 2 weeks (P≤0.05), but not at 4 weeks (P>0.05). Additionally, there was a significant difference in the total area of mineralized tissue (new bone plus particles), favoring the standard control over the test material: 43.2 ± 14.4% vs. 14.2 ± 5.3% at 2 weeks and 56.9 ± 4.2% vs. 24.2 ± 9.6% at 4 weeks, respectively. Conclusions: The test ABM/P‐15 CMC‐hydrogel graft material behaved in this animal model by migration of the graft particles, what determined an unpredictable osseoconduction and, consequently, a decreased quality and quantity of bone regeneration as compared with the osseopromotive behavior exhibited by the standard particulate form of the ABM/P‐15 control graft. It is therefore suggested to restrain the application of the hydrogel graft form in non‐contained anatomical bone defects.  相似文献   
70.
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