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   2527篇
  免费   149篇
  国内免费   33篇
耳鼻咽喉   15篇
儿科学   41篇
妇产科学   44篇
基础医学   374篇
口腔科学   17篇
临床医学   161篇
内科学   826篇
皮肤病学   17篇
神经病学   252篇
特种医学   61篇
外科学   364篇
综合类   1篇
预防医学   46篇
眼科学   13篇
药学   77篇
中国医学   3篇
肿瘤学   397篇
  2023年   18篇
  2022年   23篇
  2021年   50篇
  2020年   25篇
  2019年   41篇
  2018年   48篇
  2017年   44篇
  2016年   46篇
  2015年   65篇
  2014年   92篇
  2013年   106篇
  2012年   178篇
  2011年   226篇
  2010年   110篇
  2009年   96篇
  2008年   200篇
  2007年   147篇
  2006年   147篇
  2005年   172篇
  2004年   155篇
  2003年   130篇
  2002年   167篇
  2001年   28篇
  2000年   19篇
  1999年   25篇
  1998年   52篇
  1997年   41篇
  1996年   41篇
  1995年   43篇
  1994年   30篇
  1993年   13篇
  1992年   15篇
  1991年   10篇
  1990年   14篇
  1989年   16篇
  1988年   11篇
  1987年   8篇
  1986年   4篇
  1985年   4篇
  1984年   6篇
  1983年   5篇
  1982年   5篇
  1981年   4篇
  1980年   3篇
  1979年   7篇
  1978年   2篇
  1977年   6篇
  1974年   2篇
  1955年   2篇
  1954年   1篇
排序方式: 共有2709条查询结果,搜索用时 31 毫秒
101.
PURPOSE: The aim of this study was to clarify the distribution of lymph node metastasis in colorectal cancer. We also examined the relationship between the primary tumor (T) and the regional node (N) categories of the TNM (primary tumor, regional nodes, metastasis) classification. METHOD: Lymph nodes of surgical specimens in 311 consecutive patients with colorectal cancer were studied using the modified clearing method. RESULTS: Lymph node metastasis was seen in 59.2 percent of the total cases. The upward metastasis rate was 30.7 percent. In the longitudinal spread, most of the lymph node metastasis was seen within 10 cm. On the oral side in rectal cancer, there was no metastasis beyond 4 cm. The lateral metastasis rate in rectal cancer was 8.8 percent and in the lower rectum, the rate of cancer within 6 cm from the anal verge or beyond pT3 was much higher. CONCLUSION: In the TNM classification, there was no significant difference between colon and rectal cancer except pT1 with rectal cancer. In the lower rectal cancer within 6 cm from the anal verge or beyond pT3, there is a high risk of lateral metastasis, and lateral lymph node dissection or radiation therapy should be performed.  相似文献   
102.
The aim of the present study was to explore the unfavorable subset of patients with Stage II gastric cancer for whom surgery alone is the standard treatment (T1N2M0, T1N3M0, and T3N0M0). Recurrence-free survival rates were examined in 52 patients with stage T1N2-3M0 and stage T3N0M0 gastric cancer between January 2000 and March 2010. Univariate and multivariate analyses were performed to identify risk factors using a Cox proportional hazards model. The recurrence-free survival (RFS) rates of the patients with stages T1N2, T1N3, and T3N0 cancer were 80.0, 76.4, and 100% at 5 years, respectively. The only significant prognostic factor for the survival rates of the patients with stage pT1N2-3 cancer measured by univariate and multivariate analyses was pathological tumor diameter. The 5-year RFS rates of the patients with stage pT1N2-3 cancer were 60.0%, when the tumor diameters measured <30 mm, and 88.9% when the tumor diameters measured >30 mm (P = 0.0248). These data may suggest that pathological tumor diameter is associated with poor survival in patients with small T1N2-3 tumors. Because our study was a retrospective single-center study with a small sample size, a prospective multicenter study is necessary to confirm whether small tumors are risk factor for the RFS in T1N2-3 disease.Key words: Gastric cancer, Stage II, Adjuvant chemotherapyEvery year, more than 934,000 people develop gastric cancer worldwide. After lung cancer, gastric cancer is the second most frequent cancer-related cause of death.1 Complete resection is essential to cure gastric cancer. Patients with stage II or stage III gastric cancer often develop tumor recurrence, even after complete curative resections.In 2007, the Adjuvant Chemotherapy Trial of S-1 for Gastric Cancer (ACTS-GC) phase III trial demonstrated that S-1 is effective as adjuvant chemotherapy in Japanese patients who have undergone curative D2 gastrectomy for advanced gastric cancer.2 In general, patients eligible for ACTS-GC were those diagnosed with pathological stages II and III. However, patients classified with pathological (p) stages T1N2M0, T1N3M0, and T3N0M0—which are classified as part of stage II—were excluded from the ACTS-GC trial. Because in the prior phase III studies comparing surgery alone and adjuvant chemotherapy, patients with stages T1N+ and T2-3/N0 cancer had excellent prognoses with 5-year overall survival (OS) rates of more than 80% from surgery alone,3,4 these patients were excluded from receiving adjuvant chemotherapy. Japanese Gastric Cancer Association (JGCA) guidelines clearly state that the standard treatment for these patients is surgery alone.5Therefore, patients with stage II gastric cancer have been divided into two groups: one for whom the standard treatment is surgery alone, and the other for whom the standard treatment is surgery and adjuvant chemotherapy with S-1. Before the advent of ACTS-GC, survival rates were poorer in the latter group than in the former. However, treatment with adjuvant chemotherapy with S-1 has reversed this trend. Now, patients in the latter group receiving S-1 adjuvant chemotherapy have 5-year OS rates of 84.2%.6 Therefore, it may be old rationale that dictates that patients in the former group should be excluded from receiving adjuvant chemotherapy, because the 5-year OS rates are now more than 80% by S-1 adjuvant chemotherapy in the latter group. Five-year OS rates of 80% would not be obtained by surgery alone. Among those patients with stage II gastric cancer assigned to the surgery alone group, some may have a poor prognosis and be good candidates for adjuvant chemotherapy. The aim of the present study was to explore the unfavorable subset of patients among those with stage II gastric cancer for whom surgery alone is the standard treatment (T1N2M0, T1N3M0, and T3N0M0).  相似文献   
103.
Chromosomal translocations that involve the monocytic leukemia zinc finger (MOZ) gene are typically associated with human acute myeloid leukemia (AML) and often predict a poor prognosis. Overexpression of HOXA9, HOXA10, and MEIS1 was observed in AML patients with MOZ fusions. To assess the functional role of HOX upregulation in leukemogenesis by MOZ–TIF2, we focused on bromodomain-PHD finger protein 1 (BRPF1), a component of the MOZ complex that carries out histone acetylation for generating and maintaining proper epigenetic programs in hematopoietic cells. Immunoprecipitation analysis showed that MOZ–TIF2 forms a stable complex with BRPF1, and chromatin immunoprecipitation analysis showed that MOZ–TIF2 and BRPF1 interact with HOX genes in MOZ–TIF2-induced AML cells. Depletion of BRPF1 decreased the MOZ localization on HOX genes, resulting in loss of transformation ability induced by MOZ–TIF2. Furthermore, mutant MOZ–TIF2 engineered to lack histone acetyltransferase activity was incapable of deregulating HOX genes as well as initiating leukemia. These data indicate that MOZ–TIF2/BRPF1 complex upregulates HOX genes mediated by MOZ-dependent histone acetylation, leading to the development of leukemia. We suggest that activation of BRPF1/HOX pathway through MOZ HAT activity is critical for MOZ–TIF2 to induce AML.  相似文献   
104.
Essential thrombocythemia (ET) is a subtype of myeloproliferative neoplasms. Approximately half of the patients with ET harbor a gain-of-function mutation in the JAK2 gene (JAK2-V617F), a small percentage have mutations in codon 515 of MPL (thrombopoietin receptor) gene, and the rest have neither mutation. Pregnancy is a rare complication of ET, and it has been reported that the number of blood platelets falls with pregnancy in ET patients and the number of blood platelets increases again after a delivery and this phenomenon is observed in JAK2-V617F-positive and JAK2-V617F-negative patients. We report the first case of an ET patient with MPL mutations, whose platelet count improved with the onset of menopause, not pregnancy, and the MPL mutation also simultaneously disappeared.  相似文献   
105.
106.
Cryptococcal meningitis is rarely complicated by immune‐mediated leukoencephalopathy, but the precise pathomechanism is uncertain. A 72‐year‐old Japanese man treated with prednisolone for Sweet disease developed a subacute progression of meningitis, which was considered as neuro‐Sweet disease. A treatment by methylprednisolone rapidly improved CSF findings with a remarkable decrease in lymphocyte numbers in the blood, but the patient's consciousness still worsened after the cessation of the treatment. The patient developed cryptococcal meningitis and MRI showed abnormal intensities predominantly in the cerebral deep white matter along with the recovery of lymphocyte numbers in the blood, which resulted in death. A postmortem examination of the brain revealed degenerative lesions, especially at the cerebral white matter and cortex adjacent to the leptomeninges abundantly infiltrated by Cryptococcus neoformans. In the affected cerebral deep white matter, perivascular infiltration of lymphocytes was prominent in coexistence with reactive astrocytes and vascular proliferation, but these findings were not observed in the subcortical and cortical lesions. Cryptococcus neoformans was not present within the brain parenchyma. This is the first report of a case suggesting that cryptococcal meningitis can accompany lymphocytic inflammation predominantly in cerebral deep white matter as a possible manifestation of immune reconstitution inflammatory syndrome.  相似文献   
107.
108.
Skin homeostasis is maintained by the continuous proliferation and differentiation of epidermal cells. The skin forms a strong but flexible barrier against microorganisms as well as physical and chemical insults; however, the physiological mechanisms that maintain this barrier are not fully understood. Here, we have described a mutant mouse that spontaneously develops pruritic dermatitis as the result of an initial defect in skin homeostasis that is followed by induction of a Th2-biased immune response. These mice harbor a mutation that results in a single aa substitution in the JAK1 tyrosine kinase that results in hyperactivation, thereby leading to skin serine protease overexpression and disruption of skin barrier function. Accordingly, treatment with an ointment to maintain normal skin barrier function protected mutant mice from dermatitis onset. Pharmacological inhibition of JAK1 also delayed disease onset. Together, these findings indicate that JAK1-mediated signaling cascades in skin regulate the expression of proteases associated with the maintenance of skin barrier function and demonstrate that perturbation of these pathways can lead to the development of spontaneous pruritic dermatitis.  相似文献   
109.
Preconditioning the rat brain with spreading depression for 48 h induces potent ischemic tolerance (infarct tolerance) after an interval of 12-15 days, consequently reducing the infarcted lesion size in the acute phase following focal cerebral ischemia. However, persistence of the morphological and functional neuroprotection has not yet been proven. We tested whether tolerance-derived neuroprotection against focal cerebral ischemia persists or merely delays the progress of cerebral infarction. Prolonged spreading depression was induced in mice by placing a depolarized focus with intracerebral microinfusion of KCl for 24 h; after intervals of 3, 6, 9 or 12 days, temporary focal ischemia was imposed. In the analysis of the infarcted lesion volume 24 h after ischemia, groups with 6 or 9 day interval demonstrated significantly smaller lesion volume compared to time-matched vehicle control group (P=0.002). Significant reduction in cerebral infarction was also observed at the chronic phase, namely 14 days after ischemia (33% reduction) (P=0.021) accompanied with less severe neurological deficits (38% reduction) (P=0.020). Using this technique, we also investigated if the mice with targeted disruption of a single BDNF allele (heterozygous BDNF-deficient mice) can gain the same potency of tolerance as the wild mice. In the result on infarcted lesion volumes following temporary focal ischemia, potent tolerance developed in the wild type (35% reduction) (P=0.007) but not in the heterozygous BDNF-deficient mice (<19% reduction) (P=0.155), indicating that BDNF expression level following spreading depression is contributing to infarct tolerance development.  相似文献   
110.
Type 1 diabetes is a disease characterized by destruction of pancreatic β‐cells, which leads to absolute deficiency of insulin secretion. Depending on the manner of onset and progression, it is classified as fulminant, acute‐onset or slowly progressive type 1 diabetes. Here, we propose the diagnostic criteria for acute‐onset type 1 diabetes mellitus. Among the patients who develop ketosis or diabetic ketoacidosis within 3 months after the onset of hyperglycemic symptoms and require insulin treatment continuously after the diagnosis of diabetes, those with anti‐islet autoantibodies are diagnosed with ‘acute‐onset type 1 diabetes mellitus (autoimmune)’. In contrast, those whose endogenous insulin secretion is exhausted (fasting serum C‐peptide immunoreactivity <0.6 ng/mL) without verifiable anti‐islet autoantibodies are diagnosed simply with ‘acute‐onset type 1 diabetes mellitus’. Patients should be reevaluated after certain periods in case their statuses of anti‐islet autoantibodies and/or endogenous insulin secretory capacity are unknown.  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