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   6317篇
  免费   310篇
  国内免费   49篇
耳鼻咽喉   94篇
儿科学   153篇
妇产科学   29篇
基础医学   928篇
口腔科学   124篇
临床医学   360篇
内科学   1727篇
皮肤病学   196篇
神经病学   417篇
特种医学   159篇
外科学   1002篇
综合类   12篇
一般理论   1篇
预防医学   147篇
眼科学   132篇
药学   355篇
  1篇
中国医学   5篇
肿瘤学   834篇
  2024年   12篇
  2023年   46篇
  2022年   64篇
  2021年   148篇
  2020年   85篇
  2019年   89篇
  2018年   130篇
  2017年   101篇
  2016年   123篇
  2015年   145篇
  2014年   206篇
  2013年   208篇
  2012年   376篇
  2011年   350篇
  2010年   261篇
  2009年   208篇
  2008年   435篇
  2007年   420篇
  2006年   438篇
  2005年   478篇
  2004年   471篇
  2003年   461篇
  2002年   460篇
  2001年   76篇
  2000年   60篇
  1999年   65篇
  1998年   88篇
  1997年   87篇
  1996年   80篇
  1995年   70篇
  1994年   41篇
  1993年   55篇
  1992年   24篇
  1991年   36篇
  1990年   34篇
  1989年   33篇
  1988年   14篇
  1987年   13篇
  1986年   14篇
  1985年   18篇
  1984年   21篇
  1983年   9篇
  1982年   14篇
  1981年   13篇
  1980年   13篇
  1978年   14篇
  1977年   9篇
  1976年   6篇
  1975年   6篇
  1974年   14篇
排序方式: 共有6676条查询结果,搜索用时 15 毫秒
61.
62.
PPP1R1B-STARD3-TCAP-PNMT-PERLD1-ERBB2-MGC14832-GRB7 locus at human chromosome 17q12 is frequently amplified in human gastric cancer and breast cancer. Here, we compared human GSDML-GSDM locus with rodent genomes by using bioinformatics. Rodent ortholog of human GSDML was not identified. Rat Gsdm gene was identified within rat genome clone CH230-28N16 (AC119462.4), and was mapped to rat chromosome 10q31. Rat Gsdm gene, consisting of 12 exons, encoded a 446-amino-acid protein, which showed 86.3% and 32.3% total-amino-acid identities with human GSDM and GSDML, respectively. Mouse Gsdm-like 1 (Gsdml1) and Gsdml2 genes were identified within mouse genome clone RP23-438D7 (AL591125.20). Gsdml1 and Gsdml2 genes were found to encode 456- and 443-amino-acid proteins, respectively. Mouse 2200001G21Rik cDNA (AK008613.1) was a partial cDNA derived from mouse Gsdml2 gene. Mouse Gsdml1 and Gsdml2 were also more homologous to human GSDM than to human GSDML. Mouse Gsdml1, Gsdml2 and Gsdm genes, existing in the tandem homologous gene cluster, was mapped to mouse chromosome 11D. Mouse Gsdml1-Gsdml2-Gsdm gene cluster was predicted to be generated due to triplication of mouse Gsdm gene, while GSDML gene was predicted to be generated due to duplication of GSDM gene. Evolutionary recombination hotspot around the GSDML-GSDM locus was closely linked to the oncogenomic recombination hotspot around the PPP1R1B-ERBB2-GRB7 amplicon. The evolutionary recombination hotspot and oncogenomic recombination hotspot might be clustered around the fragile sites within the human genome.  相似文献   
63.
PIVKA-II-producing advanced gastric cancer   总被引:2,自引:0,他引:2  
We describe the case of a 68-year-old man with primary advanced adenocarcinoma of the stomach, who displayed extremely high plasma levels of protein induced by vitamin K antagonist (PIVKA)-II (15600mAU/ml) and normal levels of alphafetoprotein (AFP) (4ng/ml). Ultrasonography and dynamic computed tomography ruled out hepatocellular carcinoma (HCC) or liver metastasis. After preoperative chemotherapy, pancreatico-spleno total gastrectomy with D2 lymphadenectomy was performed. Postoperatively, plasma levels of PIVKA-II returned to within the normal range (29mAU/ml). Microscopic examination revealed stomach adenocarcinoma showing various histological types, such as moderately to poorly differentiated mucinous adenocarcinoma, but hepatoid differentiation of gastric adenocarcinoma was not detected. Localization of PIVKA-II and AFP within tumor cells was demonstrated by immunohistochemical staining using monoclonal antibodies. These results indicate that tumor cells from gastric cancer may produce PIVKA-II. Some cases of PIVKA-II- and AFP-producing advanced gastric cancer with liver metastasis have been reported, but this is the first report of gastric cancer without liver metastasis producing PIVKA-II alone.  相似文献   
64.
65.
BACKGROUND/AIMS: The multiple occurrence of primary squamous cell carcinoma of the esophagus is often observed, and most such occurrences are double cancers. There have also been some cases with three or more intra-esophageal cancers, however, no detailed clinicopathologic study has yet been performed in the literature. METHODOLOGY: Two hundred and fifty patients of primary esophageal squamous cell carcinoma without preoperative treatment that underwent esophageal resection were re-evaluated by serial histopathologic investigations and we analyzed the data of ten patients with three or more intraesophageal cancers. RESULTS: The clinical and histopathologic characteristics were as follows; 1) all but one of the cases were male, 2) all patients had a history of both heavy smoking and drinking but only one case had a family history of esophageal cancers among their siblings, 3) the depth of invasion in the carcinomas was restricted to within the submucosal layer of the esophageal wall, which was defined as superficial esophageal carcinoma, almost all (90%) of the cases accompanied esophageal squamous epithelial dysplasia. CONCLUSIONS: Based on these prominent characteristics of considerable multiple intra-esophageal cancers, a new clinical entity of "esophageal field cancers" could thus be suggested.  相似文献   
66.
A 68-year-old man was admitted after fever and general fatigue with severe inflammatory signs and anemia. T1- and T2-weighted magnetic resonance imaging showed low- to isointensity and low-intensity tumor in the right kidney, respectively, suggesting renal actinomycosis. However, the right kidney was explored transabdominally because the possibility of renal malignant lymphoma could not be excluded. After nephrectomy, characteristic colonies of Actinomyces were seen microscopically, and the histologic diagnosis was renal actinomycosis. The patient was treated with antibiotics and made good progress after operation. This case highlights the importance of magnetic resonance imaging for the diagnosis of renal actinomycosis.  相似文献   
67.
Codeine phosphate-induced hypersensitivity syndrome   总被引:2,自引:0,他引:2  
OBJECTIVE: To report a case of drug-induced hypersensitivity syndrome related to codeine phosphate. CASE SUMMARY: A 19-year-old Japanese man was prescribed codeine phosphate 10 mg 3 times daily and several other drugs for cold symptoms. About 20 days later, an erythematous, maculopapular rash appeared and progressed to erythroderma; a spiking fever also developed. He had splenomegaly and generalized lymphadenopathy on admission. Laboratory examinations showed atypical lymphocytosis, eosinophilia, and increased liver enzyme values. The platelet count slowly decreased after admission. The increased numbers of megakaryocytes in bone marrow and platelet-associated immunoglobulin (Ig) G antibodies in serum were compatible with a diagnosis of immune thrombocytopenic purpura. A significant increase in IgG antibodies to human herpesvirus 6 (HHV6) and transient viremia were helpful in diagnosing hypersensitivity syndrome. The results of patch tests were positive for codeine phosphate. An objective causality assessment revealed that an adverse drug event was probable. DISCUSSION: Codeine is an opioid analgesic. Severe adverse cutaneous reactions rarely occur. As of March 3, 2004, our case is, to our knowledge, the first report of hypersensitivity syndrome attributed to codeine phosphate. Drug-induced hypersensitivity syndrome is an acute, potentially life-threatening, idiosyncratic adverse reaction caused mainly by aromatic anticonvulsants. It is characterized by the triad of fever, skin rash, and internal organ involvement. Reactivation of HHV6 is involved in the pathogenesis of this syndrome and may have also caused the immune thrombocytopenic purpura in our patient. CONCLUSIONS: Codeine phosphate may rarely be associated with hypersensitivity syndrome. Clinicians should be aware that the potentially fatal syndrome can be caused by various drugs.  相似文献   
68.
OBJECT: Intracranial vertebral artery (VA) dissection with subarachnoid hemorrhage is notorious for frequent rebleeding and a poor prognosis. Nevertheless, some patients survive with a good final outcome. The factors associated with the prognosis of this disease are not fully understood and appropriate treatment strategies continue to be debated. The authors retrospectively evaluated the clinical features of conservatively treated patients to elucidate the relationship between the clinical and angiographic characteristics of the disease and final outcomes. METHODS: This study includes 24 patients who were treated by conservative methods between 1990 and 2000. Conservative treatment was chosen because of delayed diagnosis, poor clinical condition, or anatomical features such as bilateral lesions and contralateral VA hypoplasia. Of nine patients with an admission Hunt and Kosnik Grade I or II, eight had good outcomes (mean follow-up period 8 years and 4 months). All 15 patients with Grade III, IV, or V died and in 10 of these the cause of death was rebleeding. Among the 24 patients, 14 suffered a total of 35 rebleeding episodes; in 10 (71.4%) of these 14 patients rebleeding occurred within 6 hours and in 13 (93%) within 24 hours. Compared with the survivors, there was a female preponderance (0.022) among patients who died. These patients also had significantly shorter intervals between onset and hospital admission (p = 0.0067), a higher admission Hunt and Kosnik grade (p = 0.0001), a higher incidence of prehospitalization (p = 0.0296) and postadmission (p = 0.0029) rebleeding episodes, and a higher incidence of angiographically confirmed pearl-and-string structure of the lesion (p = 0.0049). CONCLUSIONS: In our series of preselected patients, poor admission neurological grade, rebleeding episode(s), and lesions with a pearl-and-string structure were predictive of poor outcomes. Our findings indicate that patients with these characteristics may be candidates for aggressive attempts to prevent rebleeding during the acute stage. Patients without these characteristics may be good candidates for conservative treatment, especially those who survive the acute phase without rebleeding.  相似文献   
69.
70.
Generally, hepatoma is not a chemosensitive tumor, and the mechanism of resistance to anticancer drugs is not fully elucidated. We aimed to comprehensively evaluate the relationship between chemosensitivity and gene expression profile in human hepatoma cells, by using microarray analysis, and analyze the data by constructing relevance networks. In eight hepatoma cell lines (HLE, HLF, Huh7, Hep3B, PLC/PRF/5, SK-Hep1, Huh6, and HepG2), the baseline expression levels of 2300 genes were measured by cDNA microarray. The concentrations of eight anticancer drugs (nimustine, mitomycin C, cisplatin, carboplatin, doxorubicin, epirubicin, mitoxantrone, and 5-fluorouracil) needed for 50% growth inhibition were examined and used as a measure of chemosensitivity. These data were combined and comprehensive pair-wise correlations between gene expression levels and the 50% growth inhibition values were calculated. Significant correlations with significance were used to construct networks of similarity. Fifty-two relations, including 42 genes, were selected. Among them, nearly 20% were various types of transporters, and most of them negatively correlated with chemosensitivity. Transporter associated with antigen processing 1 was associated with resistance to mitoxantrone, consistent with previous reports. Other transporters were not reported previously to associate with chemosensitivity. Resistance to doxorubicin and its analogue, epirubicin, were positively correlated with topoisomerase II beta expression, whereas it negatively correlated with expression of carboxypeptidases A3 and Z. Response to nimustine was associated with expression of superoxide dismutase 2. Relevance networks identified several negative correlations between gene expression and resistance, which were missed by hierarchical clustering. Our results suggested the necessity of systematically evaluating the transporting systems that may play a major role in resistance in hepatoma. This may provide useful information to modify anticancer drug action in hepatoma.  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