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   1388篇
  免费   141篇
  国内免费   3篇
耳鼻咽喉   12篇
儿科学   14篇
妇产科学   4篇
基础医学   452篇
口腔科学   9篇
临床医学   126篇
内科学   399篇
皮肤病学   27篇
神经病学   114篇
特种医学   42篇
外科学   135篇
综合类   5篇
一般理论   44篇
预防医学   47篇
眼科学   10篇
药学   64篇
肿瘤学   28篇
  2021年   46篇
  2020年   20篇
  2019年   36篇
  2018年   32篇
  2017年   19篇
  2016年   22篇
  2015年   28篇
  2014年   31篇
  2013年   36篇
  2012年   55篇
  2011年   49篇
  2010年   58篇
  2009年   39篇
  2008年   38篇
  2007年   47篇
  2006年   36篇
  2005年   43篇
  2004年   36篇
  2003年   39篇
  2002年   33篇
  2001年   40篇
  2000年   32篇
  1999年   44篇
  1998年   17篇
  1997年   13篇
  1996年   11篇
  1995年   14篇
  1994年   12篇
  1993年   17篇
  1992年   58篇
  1991年   40篇
  1990年   51篇
  1989年   40篇
  1988年   51篇
  1987年   36篇
  1986年   36篇
  1985年   40篇
  1984年   24篇
  1983年   21篇
  1982年   11篇
  1981年   16篇
  1980年   15篇
  1979年   23篇
  1978年   17篇
  1977年   18篇
  1976年   8篇
  1975年   8篇
  1973年   11篇
  1972年   11篇
  1970年   9篇
排序方式: 共有1532条查询结果,搜索用时 31 毫秒
991.
J. Capron  O. Steichen 《Infection》2009,37(2):179-180
Abstract   A 97-year-old lady was hospitalized for left leg cellulitis. Comorbidity included hypertension and congestive heart failure. While in hospital, she developed a painless vesicular rash localized to the territory of the left trigeminal nerve (third branch), which evolved to pustules and crusts (Figure 1). A chickenpox-like disseminated eruption of vesicles followed within 4 days, with the same evolution pattern (Figure 2). The diagnosis of disseminated zoster was suspected. A PCR analysis confirmed the presence of varicella-zoster-virus (VZV) in an abdominal vesicle. The patient was treated with oral valacyclovir for 7 days. Clinical examination, laboratory tests (including HIV serology), and a chest radiograph revealed no evidence of underlying immunodeficiency or malignancy.  相似文献   
992.
When illuminated with a certain wavelength, lung tissue emits a weak fluorescence. The fluorescence from normal tissue is different from that from diseased tissue. This technique can thus be used for early diagnosis of precancerous lesions. Technical manipulations are required to amplify the fluorescence signal. Numerous studies have used the LIFE (Lung Imaging Fluorescent Endoscope) to study lung diseases. This system of detection uses a laser helium-cadmium excitation source; the principal photosensitizing agents are hematoporphyrin derivatives. The cost, bulkiness and secondary effects have limited diffusion of this type of photodynamic diagnostic system. We have used 2 systems (SAFE 1000 Pentax and D-LIGHT Storz) successively in a prospective study to analyze autofluorescence of lung tissue without laser illumination or photosensitization. Fifty-four patients were selected for their risk factors. We were able to detect one case of severe dysplasia but did not identify any case of carcinoma in situ. Among 18 cases, 16 were evident with white light. Two were detected with autofluorescence used to orient biopsies while white light had only revealed a common inflammatory aspect. Thirty-nine low-grade lesions (metaplasia, dysplasia) were found. The systems are easy to use. Lower cost would allow more widespread use of these systems currently reserved for risk populations. These techniques broaden the scope of interventional endoscopy.  相似文献   
993.
994.
Multicentric thyroid papillary carcinomas were present in two sisters with familial polyposis of the colon; in one the tumor was found at age 29 and in the other at 26 years of age, respectively 13 and 5 years after colectomy. This association is not fortuitous and should lead to regular examination of thyroid gland in patients with familial polyposis or in Gardner's syndrome patients. It might even be wise to search for adenomas of the colon in young patients with thyroid carcinoma.  相似文献   
995.
996.
Invariant natural killer T (iNKT) cells are a subset of innate lymphocytes that recognize lipid antigens in the context of CD1d and mediate potent immune regulatory functions via the rapid production of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4). We investigated whether diverse Toll-like receptor (TLR) signals in myeloid dendritic cells (DCs) could differentially stimulate iNKT cells. Together with the lipopolysaccharide-detecting receptor TLR4, activation of the nucleic acid sensors TLR7 and TLR9 in DCs were particularly potent in stimulating iNKT cells to produce IFN-gamma, but not IL-4. iNKT cell activation in response to TLR9 stimulation required combined synthesis of type I interferon and de novo production of charged beta-linked glycosphingolipid(s) by DCs. In addition, DCs stimulated via TLR9 activated both iNKT cells and NK cells in vivo and protected mice against B16F10-induced melanoma metastases. These data underline the role of TLR9 in iNKT cell activation and might have relevance to infectious diseases and cancer.  相似文献   
997.
Galectin-3 (Gal-3) is a multifunctional beta-galactoside-binding lectin that senses self-derived and microbial glycoconjugates. Although Gal-3 is important in immune reactions and host defense in some experimental models, the function of Gal-3 during helminthic diseases (e.g., schistosomiasis) is still elusive. We show that, compared to wild-type Schistosoma mansoni-infected mice, infected Gal-3-/- mice have a reduced number of T and B lymphocytes in the spleen, develop reduced liver granulomas at 7 weeks (acute phase) and 14 weeks (chronic phase) postinfection, and mount a biased cellular and humoral Th1 response. In an attempt to understand this latter phenomenon, we studied the role of endogenous Gal-3 in dendritic cells (DCs), the most potent antigen-presenting cells, both in vitro and in vivo. Although Gal-3 deficiency in DCs does not impact their differentiation and maturation processes, it greatly influences the strength (but not the nature) of the adaptive immune response that they trigger, suggesting that Gal-3 deficiency in some other cell types may be important during murine schistosomiasis. As a whole, this study implies that Gal-3 is a modulator of the immune/inflammatory responses during helminthic infection and reveals for the first time that Gal-3 expression in DCs is pivotal to control the magnitude of T-lymphocyte priming.  相似文献   
998.
A clinical study was carried out to compare the response rate of two groups of non-responder (NR) hepatitis C virus (HCV) genotype 1 chronically infected patients treated with interferon and ribavirin, with or without amantadine. The viral load decreased more markedly in the group treated by tritherapy including amantadine, but the response rate at the end of treatment was not significantly different between bitherapy and tritherapy. As amantadine could have an antiviral effect on the ion channel activity of the p7 HCV protein, the p7 quasispecies was characterized by cloning and sequencing. Sequence data were analyzed to determine the pattern and significance of p7 genetic heterogeneity and a possible relationship with therapy. Subtype differences were confirmed between p7 HCV genotypes 1a and 1b, and quasispecies analysis showed a reduction of genetic diversity in subtype 1a, but not 1b, during tritherapy. However, the absence of changes at numerous positions, as well as the conservative changes at other positions, indicated the high conservation of the p7 structure. Residue His-17, proposed to interact with amantadine, was fully conserved in both subtypes 1a and 1b, independently of amantadine administration. In conclusion, although the analysis of the p7 sequences revealed a selective pressure during therapy, no specific residues appeared to be linked to the effect of amantadine on viral decline. These results suggest that the potential antiviral effect of amantadine might be non-specific and related to a reduction in endosomal acidification and therefore reduced viral entry of HCV via its pH-dependent pathway.  相似文献   
999.
Obstructive sleep apnea (OSA) is associated with impaired airway reflexes. Cough is the main airway defense mechanism but the effect of OSA on cough is unknown. Thirty-two female obese patients scheduled to undergo bariatric surgery were studied. They were classified as presenting OSA (20 patients) when the apnea-hypopnea index (AHI) was greater than 5h. Cough sensitivity was measured with citric acid. Increasing concentrations of nebulized citric acid were delivered until cough was elicited. The concentrations eliciting one (C1) and two coughs (C2) were recorded and log transformed (log C1 and log C2). log C1 and log C2 (median (interquartile)) were 1.90 mg/mL (0.90) and 2.2mg/mL (0.30) in OSA patients and 1.60 mg/mL (0.45) and 1.60 mg/mL (0.45) in non-OSA patients, respectively (comparison between groups: p=0.0372 for log C1 and p=0.0227 for log C2). A significant relationship was observed between AHI and log C1 and log C2. Cough sensitivity is therefore, decreased in female obese OSA patients and this decreased sensitivity is positively correlated with disease severity.  相似文献   
1000.
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