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   7885篇
  免费   532篇
  国内免费   50篇
耳鼻咽喉   120篇
儿科学   170篇
妇产科学   127篇
基础医学   965篇
口腔科学   269篇
临床医学   646篇
内科学   1649篇
皮肤病学   165篇
神经病学   516篇
特种医学   313篇
外国民族医学   2篇
外科学   1243篇
综合类   133篇
一般理论   5篇
预防医学   542篇
眼科学   360篇
药学   733篇
中国医学   73篇
肿瘤学   436篇
  2024年   4篇
  2023年   91篇
  2022年   118篇
  2021年   376篇
  2020年   249篇
  2019年   315篇
  2018年   403篇
  2017年   270篇
  2016年   329篇
  2015年   320篇
  2014年   469篇
  2013年   573篇
  2012年   802篇
  2011年   793篇
  2010年   462篇
  2009年   324篇
  2008年   513篇
  2007年   474篇
  2006年   363篇
  2005年   297篇
  2004年   224篇
  2003年   232篇
  2002年   176篇
  2001年   34篇
  2000年   24篇
  1999年   35篇
  1998年   24篇
  1997年   13篇
  1996年   17篇
  1995年   13篇
  1994年   12篇
  1993年   12篇
  1992年   4篇
  1991年   9篇
  1990年   4篇
  1989年   11篇
  1988年   11篇
  1987年   4篇
  1986年   2篇
  1985年   5篇
  1984年   5篇
  1982年   8篇
  1981年   4篇
  1980年   3篇
  1979年   4篇
  1978年   5篇
  1977年   3篇
  1976年   7篇
  1975年   7篇
  1974年   6篇
排序方式: 共有8467条查询结果,搜索用时 15 毫秒
91.
92.
ObjectiveTo assess the quality of expressed MSP-2 and also to confirm the immune response against different domains of these proteins.MethodsMice were immunized with a schizont extract to stimulate the immune system to make antibodies against different antigens of the late stage parasite including production of antibodies against different domains of Plasmodium falciparum (P. falciparum) MSP-2. B lymphocytes of immunized mice were extracted from the spleen and the fusion was performed using NS-1 myeloma cells and the hybridoma cells were assayed by ELISA either with a schizont extract or different domains of MSP-2 and/or by IFAT with whole schizont preparation. Fusion of NS-1 and spleen cells was performed. The positive hybrids were cloned and ELISA was applied against different dilutions. The positive clones were transferred to a small tissue culture flask and after developing they were assayed against schizont extract and the different MSP-2 domains. The positive clones were expanded to large (75 cm2) flask and cultured under the same conditions, checking them using both ELISA and IFAT and the positive cells were frozen as soon as possible.ResultsA total number of 7 fusions including 26 plates (2 496 wells) were performed, of which 1 336 hybrids were produced and the overall efficiency (1 336/2496 × 100) was about 53%. ELISA was performed to detect the positive hybrids against crude schizont extract by which the highest frequency to crude schizont extract was found for the supernatant of the hybrids produced in fusion number 3 (66 out of 315 hybrids). The supernatant of both B5 and F1 hybridoma cells were more positive against domain 2 of the MSP-2 recombinant protein in Western blotting test. Western blotting results also showed that different domains of the MSP-2 recombinant protein and also the MSP-2 of the P. falciparum parasite were recognized by some of the positive clones and also immune sera.ConclusionsBringing together all the results of this study it has been confirmed that some clones have recognized both schizont extract and different domains of the MSP-2 recombinant protein and therefore confirming the quality of the MSP-2 domains.  相似文献   
93.
Cytokines are mediators for polarization of immune response in vaccines. Studies show that co‐immunization of DNA vaccines with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) can increase immune responses. Here, experimental mice were immunized with HIV‐1tat/pol/gag/env DNA vaccine with GM‐CSF and boosted with recombinant vaccine. Lymphocyte proliferation with Brdu and CTL activity, IL‐4, IFN‐γ, IL‐17 cytokines, total antibody, and IgG1 and IgG2a isotypes were assessed with ELISA. Results show that GM‐CSF as adjuvant in DNA immunization significantly increased lymphocyte proliferation and IFN‐γ cytokines, but CTL response was tiny increased. Also GM‐CSF as adjuvant decreased IL‐4 cytokine vs mere vaccine group. IL‐17 in the group that immunized with mixture of DNA vaccine/GM‐CSF was significantly increased vs DNA vaccine group. Result of total antibody shows that GM‐CSF increased antibody response in which both IgG1 and IgG2a increased. Overall, results confirmed the beneficial effect of GM‐CSF as adjuvant to increase vaccine immunogenicity. The hallmark result of this study was to increase IL‐17 cytokine with DNA vaccine/GM‐CSF immunized group. This study for the first time provides the evidence of the potency of GM‐CSF in the induction of IL‐17 in response to a vaccine, which is important for control of infection such as HIV‐1.  相似文献   
94.
95.
Aim:  Iran's health-care system has witnessed profound changes in the last decades. Despite its progress, the system has currently faced many challenges in one of the important subsystems, nursing. The present review article aimed to present an overview of the opportunities and challenges of the Iranian nursing system, based on recent literature.
Methods:  A broad search of the English and Persian-language literature was carried out, incorporating both electronic and manual components from 1999 to 2009. The results of the investigations among the searched literature are summarized.
Results:  The major challenges are nursing shortages, job dissatisfaction, poor social position of nurses, the gap between theory and practice, lack of community-based nursing care, lack of an appropriate student recruiting system, and shortages in the nursing educational curriculums.
Conclusion:  The authors believe that media, political and public support play a pivotal role in improving the image of nursing in society, increasing motivation among Iranian nurses, and promoting the sociocultural climate and the welfare of nurses, which will result in higher levels of quality of care as well as greater patient satisfaction.  相似文献   
96.
Salmonella is the most important cause of bacterial food-borne disease outbreaks in the world. In this study, we have trained and validated artificial neural networks (ANNs) to predict the combined effect of Zataria multiflora essential oil (EO), pH, and temperature on the probability percentage of growth initiation (log P%) of Salmonella. Z. multiflora was collected in the Fars province of Iran. Lyophilized cultures of Salmonella typhimurium ATCC 25923 was used in this study. This design included four levels of EO (0.0, 0.015, 0.03, and 0.06%), three levels of pH (5.5,6, and 7.3), three storage temperatures (35, 25, and 15°C), and repeated observations (18 times) for growth in brain heart infusion broth for up to 43 days. We have designed a standard and the so-called feed-forward ANN, including four input neurons, eight neuron in hidden layer, and one output neuron to predict the combined effect of Z. multiflora EO, pH, and temperature on the probability percentage of growth initiation (log P%) of S.typhimurium. The mean and standard deviation of ANN and real outputs were −2.9771 ± 2.43 and −2.9722 ± 2.39, respectively. The mean differences (and 95% CIs) between the ANN and real outputs were 0.0049 (0.0009–0.0089). Result showed better prediction compare to the previous study(R = 0.998).  相似文献   
97.
Parasites are important enteric pathogens among patients with human immunodeficiency virus (HIV) infection. There have been very few reports on the prevalence of intestinal parasites among such patients in Iran. To determine the prevalence of intestinal parasites among HIV-positive individuals, we collected single stool samples and analyzed them for detection of various intestinal parasites from 206 HIV-positive individuals with different immune status visited in different medical centers in Iran. The data were tested for statistical significance with chi(2) and Mann-Whitney U tests. The overall prevalence of intestinal parasites was 18.4% (95%CI: 13.7, 24.3). More specifically, the following parasites were identified: Giardia lamblia (7.3%), Blastocystis hominis (4.4%), Entamoeba coli (3.9%), and Cryptosporidium parvum (1.5%). Other parasites observed included Strongyloides stercoralis and Hymenolepis nana in two cases and Dicrocoelium dendriticum in one. Of the 38 patients who tested positive for intestinal parasites, 15 (39.2%) had diarrhea. Intestinal parasites were significantly more common among patients with diarrhea than those without (P < 0.001). Further, CD4 counts were significantly lower among individuals with diarrhea than those without (P < 0.001). This study highlights the importance of testing for intestinal parasites among Iranian HIV-positive patients, especially those with low immunity presenting with diarrhea.  相似文献   
98.
99.
Hyper-immunoglobulin E syndrome is a rare primary immunodeficiency disease characterized by recurrent abscess formation, respiratory tract infections and very high titers of serum IgE associated with peculiar face and skeletal features. We report a seven-year old girl presenting with persistent productive cough and history of chronic eczematoid facial lesions since infancy and two episodes of hospitalizations due to pneumonia and perianal abscess. Additionally, in physical examination finger tip clubbing, laxity of joints and crackles in both lungs were detected. Immunologic work up revealed markedly raised IgE level and eosinophilia. The patient was diagnosed as hyper IgE syndrome based on his clinical and laboratory findings. Chest X-ray revealed multiple large cystic lesions in left lung which were confirmed by spiral CT-scan. Pneumonectomy specimen examination showed cystic adenomatoid malformation, characterized by the presence of various cysts lined by epithelium in different sizes. There are few reports of cystic adenomatoid malformation in children. To our best known, this is the first report of cystic adenomatoid malformation in a child with hyper IgE syndrome. Early diagnosis and surgical therapy are helpful in prevention of repeated infections in these patients.  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