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   2801篇
  免费   137篇
  国内免费   5篇
耳鼻咽喉   32篇
儿科学   78篇
妇产科学   17篇
基础医学   410篇
口腔科学   57篇
临床医学   150篇
内科学   561篇
皮肤病学   118篇
神经病学   367篇
特种医学   63篇
外科学   427篇
综合类   17篇
预防医学   66篇
眼科学   172篇
药学   192篇
中国医学   8篇
肿瘤学   208篇
  2022年   22篇
  2021年   32篇
  2020年   15篇
  2019年   22篇
  2018年   59篇
  2017年   27篇
  2016年   28篇
  2015年   40篇
  2014年   45篇
  2013年   66篇
  2012年   111篇
  2011年   113篇
  2010年   76篇
  2009年   53篇
  2008年   116篇
  2007年   99篇
  2006年   105篇
  2005年   92篇
  2004年   115篇
  2003年   108篇
  2002年   101篇
  2001年   127篇
  2000年   116篇
  1999年   108篇
  1998年   30篇
  1997年   25篇
  1996年   21篇
  1995年   29篇
  1994年   30篇
  1993年   22篇
  1992年   99篇
  1991年   82篇
  1990年   87篇
  1989年   75篇
  1988年   55篇
  1987年   74篇
  1986年   75篇
  1985年   58篇
  1984年   46篇
  1983年   33篇
  1982年   28篇
  1979年   26篇
  1977年   14篇
  1975年   22篇
  1974年   15篇
  1973年   14篇
  1972年   21篇
  1971年   14篇
  1969年   16篇
  1967年   19篇
排序方式: 共有2943条查询结果,搜索用时 15 毫秒
101.
Congenital insensitivity to pain with anhidrosis (CIPA) is identified as a genetic disorder of mutations in the human TrkA known as high affinity receptor of nerve growth factor (NGF). NGF signal through TrkA promotes anti-apoptotic activity in hematopoietic cells including B lymphocytes. Here we studied the effect of NGF on anti-apoptotic activity by using human EBV-immortalized B lymphoblastoid cell lines (EB-LCLs) derived from a patient with CIPA and the associated carriers of CIPA. The TrkA(mt/mt) EB-LCL derived from the CIPA patient and the TrkA(wt/mt) EB-LCL derived from the carrier with the heterozygous TrkA mutation did not show any responses to NGF on anti-apoptotic activity. We concluded that this phenomenon is one of the pathogeneses of CIPA.  相似文献   
102.
The MART-1/Melan-A melanoma antigen recognized by the majorityof HLA-A2-restricted tumorinfiltrating lymphocytes is a selfantigen expressed on melanocytes and the retina. We have investigatedwhether Vogt–Koyanagi–Harada (VKH) disease and sympatheticophthalmia (SO), systemic inflammatory disorders affecting variousorgans containing melanocytes, are autoimmune diseases directedtoward the MART-1 antigen. In two of three patients with VKHdisease and one patient with SO, CD8+ T cell clones (TCC) fromintraocular fluid of HLA-A2+ patients lysed T2 cells when pulsedwith a HLA-A2-binding MART-1 peptide, but not a HLA-A2-bindingpMel-17 or tyrosinase peptide, in a HLA-A2-restricted manner.These CD8+ TCC lysed both melanocytes and melanoma cells ina HLA-A2-restricted manner. In addition, CD8+ TCC recognizinga HLA-A2-binding MART-1 peptide were also established from peripheralblood mononuclear cells of a patient with VKH disease. In contrast,either CD4+ TCC from these patients or CD8+ TCC from the intraocularfluid of HLA-A2+ patients with uveitis associated with Behcet'sdisease or HTLV-I uveitis did not show this cytotoxicity. Theresults demonstrate that the MART-1 peptide-specific cytotoxicT lymphocytes lyse melanocytes in the eye of patients with VKHdisease or SO, suggesting that these diseases are autoimmunediseases directed toward the MART-1 antigen in HLA-A2+ patients.  相似文献   
103.
The distribution of the facial neurons that innervate several facial muscles was determined in the rabbit and the rat by examining the retrograde transport of horseradish peroxidase (HRP). The target muscles were musculus levator nasolabialis, m. levator labii superioris, m. zygomaticus, and m. buccinator pars buccalis, as well as m. parietoauricularis and m. depressor anguli oris in the rabbit and m. levator auricularis posterioris in the rat. Localization of the retrogradely labeled neurons within the ipsilateral facial nucleus was confirmed for all facial muscles examined. Our results showed that m. levator nasolabialis was innervated by neurons located in the dorsal subnucleus, while the motoneurons innervating m. buccinator pars buccalis were distributed within the dorsal part of the intermediate subnucleus of the facial nucleus in the both species. Localization of the labeled motoneurons innervating m. zygomaticus and m. levator labii superioris showed the difference in the distribution within the facial nucleus among the species. Neurons innervating m. parietoauricularis and m. levator auricularis posterioris were localized in somewhat different subregions of the medial subnucleus in these species. M. depressor anguli oris was innervated by the neurons distributed within the intermediate subnucleus of the facial nucleus in the rabbit. Thus, our findings revealed that there is species-specific motor innervation pattern in rabbits and rats, despite several movement of the face is supplied by the homologous facial muscles.  相似文献   
104.
The aim of the present study was to estimate the relationship between apoptosis and cell proliferation in histiocytic necrotizing lymphadenitis (HNL). Fifteen patients with HNL were retrospectively analyzed. The patients were divided into three groups according to the proportion of the necrotic area as follows: necrosis (+), necrotic area <25%; necrosis (++), necrotic area 25–50%; and necrosis (+++), necrotic area >50%. Immunohistochemical double staining was performed for CD3 plus caspase-3 and for Ki-67 plus caspase-3 and positive cells were counted in two areas: one without and one with obvious apoptotic features. Most caspase-3-positive cells were also stained for CD3 (area exhibiting obvious apoptotic features: average, 92.3%). Furthermore, various proportions of both Ki-67- and caspase-3-positive cells were detected in all the groups (range, 5–70%). In the area with obvious apoptotic changes, the average percentage of both Ki-67- and caspase-3-positive cells (38.6%) was higher than that in the area without obvious apoptotic features (16.3%). A proportion of cells in HNL undergo proliferation and apoptosis simultaneously, such as neoplastic cells, thereby exhibiting rapid cell cycles.  相似文献   
105.
We examined clinicopathologic findings in 17 cases of peripheral T-cell lymphoma, follicular variant (f-PTCL), and compared these findings with angioimmunoblastic T-cell lymphoma (AITL) to determine whether they were identical to the spectrum of changes seen in AITL and how each of the findings in f-PTCL were related to the characteristics of AITL. Almost all f-PTCL cases showed pathologic characteristics of AITL and immunohistochemical positivities in lymphoma cells for CD4, CD10, Bcl-6, PD-1, and CXCL13. Except for pathologic characteristics, clinicopathologic findings in f-PTCL had few significant differences from AITL. The positive rate for Bcl-6 expression in neoplastic cells was significantly associated with the frequency of polymorphic infiltrates, vascular proliferation, B-immunoblasts, clear cells, Epstein-Barr virus-positive lymphocytes, hepatosplenomegaly, and skin rash. Our study confirmed the continuity between f-PTCL and AITL. Moreover, Bcl-6 expression in f-PTCL was statistically associated with the characteristics of AITL.  相似文献   
106.
Rapidly adapting mechanically activated channels (RA) are expressed on somatosensory neurons and thought to play a role in mechanical transduction. Because mechanical sensations can be significantly affected by temperatures, we examined thermal sensitivity of RA currents in cultured dorsal root ganglion (DRG) neurons to see if RA channel activity is highly temperature-dependent. RA currents were evoked from DRG neurons by membrane displacements and recorded by the whole-cell patch-clamp recording technique. We found that RA currents were significantly enhanced by warming temperatures from 22 to 32 °C and reduced by cooling temperatures from 24 to 14 °C. RA channel activation exhibited steep temperature-dependence with a large temperature coefficient (Q10>5) and a high activation energy (Ea>30 kcal/mol). We further showed that RA channel activation by mechanical stimulation led to membrane depolarization, which could result in action potential firing at 22 °C or 32 °C but not at 14 °C. Taken together, our results provide the measurements of thermal dynamics and activation energy of RA channels, and suggest that a high energy barrier is present for RA channels to open. These findings are in agreement with temperature sensitivity of mechanical sensations in mammals.  相似文献   
107.
This report concerns a unique case of a composite lymphoma composed of T-lymphoblastic leukemia/lymphoma (T-LBL) and diffuse large B-cell lymphoma (DLBCL) in a 72-year-old woman with generalized lymphadenopathy, splenomegaly and ascites. Laboratory findings showed increased lactate dehydrogenase and soluble interleukin-2 receptor. The biopsy specimen showed replacement of the normal architecture of the lymph nodes by a tumor containing a dual cell population composed of large lymphocytes and medium-sized lymphocytes. Sheets of large lymphocytes often were punctuated by clusters of medium-sized lymphocytes. Flow cytometry and immunohistochemical analysis showed a composite lymphoma with both T-LBL and DLBCL. The T-LBL expressed CD1a, CD3, CD4, CD8, and terminal deoxynucleotidyl transferase. The DLBCL expressed CD19 and CD20, CD23, bcl-2, bcl-6, MUM1 and immunoglobulin κ light chain. Polymerase chain reaction detected a monoclonal pattern of T-cell receptor γ and immunoglobulin heavy chain rearrangements in the same specimen. She received eight cycles of R-CHOP (rituximab+cyclophosphamide, doxorubicin, vincristine, prednisone) therapy and achieved complete remission. She has shown no signs of recurrence 20 months after the diagnosis. We describe here a very unusual and, to the best of our knowledge, an as yet never reported case of a primary composite lymphoma of T-LBL and DLBCL.  相似文献   
108.
The immunoglobulin receptor Fc gamma RIIIa (CD16) is distributed on natural killer (NK) cells, macrophages, and gamma delta T cells, and is polymorphic. Fc gamma RIIIa-158V has a higher affinity for both monomeric and immune complexed IgG1, IgG3, and IgG4 than IIIa-158F. We determined Fc gamma RIIIa-158V/F genotypes of Japanese patients with adult periodontitis. A significant over-representation of Fc gamma RIIIa-158F was found in patients with recurrence, compared with patients without recurrence, making Fc gamma RIIIA a candidate gene for recurrence risk of adult periodontitis.  相似文献   
109.
110.
Isolation of Trichosporon asahii from environmental materials.   总被引:5,自引:0,他引:5  
Trichosporon asahii is the most clinically important pathogenic yeast in the genus Trichosporon, as this species causes both deep-seated infection and summer-type hypersensitivity pneumonitis. We isolated 29 T. asahii colonies from environmental samples using the polymerase chain reaction (PCR) and dichloran rose bengal chloramphenicol (DRBC) medium. Our results suggest that T. asahii is common in nature.  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