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   750篇
  免费   58篇
  国内免费   8篇
耳鼻咽喉   11篇
儿科学   28篇
妇产科学   5篇
基础医学   119篇
口腔科学   19篇
临床医学   73篇
内科学   209篇
皮肤病学   29篇
神经病学   40篇
特种医学   42篇
外科学   78篇
综合类   5篇
预防医学   23篇
眼科学   8篇
药学   53篇
肿瘤学   74篇
  2024年   6篇
  2023年   18篇
  2022年   46篇
  2021年   87篇
  2020年   32篇
  2019年   48篇
  2018年   43篇
  2017年   30篇
  2016年   34篇
  2015年   33篇
  2014年   34篇
  2013年   42篇
  2012年   54篇
  2011年   54篇
  2010年   26篇
  2009年   10篇
  2008年   32篇
  2007年   36篇
  2006年   21篇
  2005年   19篇
  2004年   21篇
  2003年   14篇
  2002年   15篇
  2001年   11篇
  2000年   4篇
  1999年   7篇
  1998年   4篇
  1997年   1篇
  1996年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1985年   3篇
  1984年   1篇
  1983年   3篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1974年   5篇
  1972年   2篇
  1971年   1篇
  1970年   1篇
  1968年   2篇
  1967年   1篇
排序方式: 共有816条查询结果,搜索用时 31 毫秒
81.
PurposeErectile dysfunction (ED) is one of the increasing diseases with aging society. The basis of ED derived from local penile abnormality is poorly understood because of the complex three‐dimensional (3D) distribution of sinusoids in corpus cavernosum (CC). Understanding the 3D histological structure of penis is thus necessary. Analyses on the status of regulatory signals for such abnormality are also performed.MethodsTo analyze the 3D structure of sinusoid, 3D reconstruction from serial sections of murine CC were performed. Histological analyses between young (2 months old) and aged (14 months old) CC were performed. As for chondrogenic signaling status of aged CC, SOX9 and RBPJK staining was examined.ResultsSinusoids prominently developed in the outer regions of CC adjacent to tunica albuginea. Aged CC samples contained ectopic chondrocytes in such regions. Associating with the appearance of chondrocytes, the expression of SOX9, chondrogenic regulator, was upregulated. The expression of RBPJK, one of the Notch signal regulators, was downregulated in the aged CC.ConclusionsProminent sinusoids distribute in the outer region of CC which may possess important roles for erection. A possibility of ectopic chondrogenesis induced by alteration of SOX9/Notch signaling with aging is indicated.  相似文献   
82.
The frequency distributions of the lineal energy, y, of 160 MeV proton, 150 MeV/u helium, and 490 MeV/u silicon ion beams were measured using a wall-less tissue equivalent proportional counter (TEPC) with a site size of 0.72 μm. The measured frequency distributions of y as well as the dose-mean values, y(D), agree with the corresponding data calculated using the microdosimetric function of the particle and heavy ion transport code system PHITS. The values of y(D) increase in the range of LET below ~10 keV μm(-1) because of discrete energy deposition by delta rays, while the relation is reversed above ~10 keV μm(-1) as the amount of energy escaping via delta rays increases. These results indicate that care should be taken with the difference between y(D) and LET when estimating the ionization density that usually relates to relative biological effectiveness (RBE) of energetic heavy ions.  相似文献   
83.
AIM: Intra-arterial 5-fluorouracil (5-FU) plus interferon (IFN) combination therapy is effective against advanced hepatocellular carcinoma (HCC) with portal vein tumour thrombosis. In this study, we compared the efficiency and safety of recombinant IFN-alpha-2b with natural IFN-alpha as components of the combination therapy. METHODS: Consecutive HCC patients (n=31) with portal vein tumour thrombosis were enrolled in this prospective study. They received combination therapy of 5-FU and either recombinant IFN-alpha-2b (R group, n=15) or natural IFN-alpha (N group, n=16). We compared the two groups for the early response rate, adverse reactions, time to progression (TTP) and survival rates. In addition, we assessed the cost-effectiveness of each protocol. RESULTS: The early response rate (R: 26.7%, N: 31.2%), median TTP (R: 5.8 months, N: 5.6 months) and median survival time (R: 7.5 months, N: 6.5 months) were not significantly different between the R and N groups. There were no differences in adverse reactions between the two groups. The estimated cost-effectiveness ratio of recombinant IFN-alpha-2b was better than natural IFN-alpha. CONCLUSIONS: In our protocol of combination therapy, there were no significant differences between recombinant IFN-alpha-2b and natural IFN-alpha with regard to early response to therapy, adverse effects, TTP and survival rates. 5-FU could be combined with either recombinant IFN-alpha-2b or natural IFN-alpha, although the cost-effectiveness of the former warrants its use clinically.  相似文献   
84.
Aim:  The endpoint of treatment with nucleoside analogs remains unclear for patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B. We report the results of a randomized trial to determine the optimal duration of additional therapy after response to lamivudine in HBeAg-negative patients.
Methods:  Twenty-two patients with HBeAg-negative chronic hepatitis B who exhibited biochemical and virological responses to lamivudine were enrolled. When patients responded to treatment, they were randomly assigned to receive 12 more months of therapy (Group A, 11 patients) or 24 more months of therapy (Group B, 11 patients).
Results:  The baseline characteristics of the patients were similar in the two groups. Biochemical and virological responses were obtained in all patients within 6 months. Drug resistance developed in one patient in Group A during month 7 of additional therapy, and in five patients in Group B from months 13–23 of additional therapy. Ten patients in Group A and six in Group B completed the protocol and were included in analysis. Eight of the 10 patients in Group A experienced relapse between months 2 and 14 after the discontinuation of therapy, while three of the six patients in Group B experienced relapse between months 2 and 24. There was no difference in cumulative relapse rate between the groups ( P  = 0.275).
Conclusion:  Additional therapy with lamivudine for longer than 12 months after biochemical and virological responses in patients with HBeAg-negative chronic hepatitis B could increase the risk of drug resistance, but did not reduce the rate of relapse.  相似文献   
85.
Percutaneous ethanol injection therapy was performed in a 66-year-old woman with hepatocellular carcinoma. She developed portal vein thrombosis that on color Doppler revealed no tumor vascular signal, and so was diagnosed as non-tumor thrombus. The thrombus resolved over 3 months.  相似文献   
86.
Direct-acting antivirals (DAAs) are either part of the current standard of care or are in advanced clinical development for the treatment of patients chronically infected with hepatitis C virus (HCV) genotype 1, but concern exists with respect to the patients who fail these regimens with emergent drug-resistant variants. In the present study, ultradeep sequencing was performed to analyze resistance to daclatasvir (DCV), which is a highly selective nonstructural protein 5A (NS5A) inhibitor. Eight patients with HCV genotype 1b, who were either treatment naive or prior nonresponders to pegylated interferon plus ribavirin (Rebetol; Schering-Plough) (PEG-IFN/RBV) therapy, were treated with DCV combined with PEG-IFN alpha-2b (Pegintron; Schering-Plough, Kenilworth, NJ) and RBV. To identify the cause of viral breakthrough, the preexistence and emergence of DCV-resistant variants at NS5A amino acids were analyzed by ultradeep sequencing. Sustained virological response (SVR) was achieved in 6 of 8 patients (75%), with viral breakthrough occurring in the other 2 patients (25%). DCV-resistant variant Y93H preexisted as a minor population at higher frequencies (0.1% to 0.5%) in patients who achieved SVR. In patients with viral breakthrough, DCV-resistant variant mixtures emerged at NS5A-31 over time that persisted posttreatment with Y93H. Although enrichment of DCV-resistant variants was detected, the preexistence of a minor population of the variant did not appear to be associated with virologic response in patients treated with DCV/PEG-IFN/RBV. Ultradeep sequencing results shed light on the complexity of DCV-resistant quasispecies emerging over time, suggesting that multiple resistance pathways are possible within a patient who does not rapidly respond to a DCV-containing regimen. (This study has been registered at ClinicalTrials.gov under registration no. NCT01016912.)  相似文献   
87.
88.
89.
Training rats by swimming was shown to cause changes in the functional state of the hepatocytes, accompanied by changes in the distribution of nuclei relative to their DNA ploidy classes. The blood sugar and liver glycogen concentrations of the trained animals 20 and 48 h after partial hepatectomy were significantly higher than in untrained rats. Reparative regeneration after partial hepatectomy in trained rats is characterized by a unique distribution of nuclei among DNA ploidy classes and by the entry of only diploid nuclei into the phase of synthesis 20 h after the operation.Central Research Laboratory, Novosibirsk Medical Institute. Laboratory of Endocrinology and Laboratory of Biophysics, Institute of Clinical and Experimental Medicine, Siberian Division, Academy of Medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 10, pp. 483–486, October, 1978.  相似文献   
90.
We evaluated the microbial contamination of nebulization solutions in medication cups from a total of 76 ultrasonic nebulizers in use in 10 hospitals. In addition, an interview survey was given to nurses to evaluate the disinfection methods of these ultrasonic nebulizers. Of a total of 76 nebulization solution samples, 11 (14.5%) were contaminated with 10-10(2) colony-forming units (CFU)/ml and 9 (11.8%) with 10(3)-10(5) CFU/ml. The major contaminants were glucose non-fermentative bacilli such as Burkholderia cepacia, CDC gr.IV C-2, and Sphingomonas paucimobilis. Comparison of microbial contamination between the frequencies of disinfection showed a significantly lower number of contaminated samples when the cups were disinfected once daily than when disinfected once at intervals of 2-7 d (p=0.00037). In addition, comparison between the presence and absence of preservatives contained in the nebulization solution showed a significantly lower number of contaminated samples in the presence, rather than in the absence, of preservatives (p=0.00001). These results show that disinfection of ultrasonic nebulizers at 24-h intervals is desirable. In particular, when nebulization solutions not containing preservatives are used, disinfection at 24-h intervals is indispensable.  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