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   2660篇
  免费   113篇
  国内免费   15篇
耳鼻咽喉   17篇
儿科学   38篇
妇产科学   17篇
基础医学   347篇
口腔科学   116篇
临床医学   204篇
内科学   585篇
皮肤病学   33篇
神经病学   200篇
特种医学   256篇
外科学   385篇
综合类   11篇
预防医学   97篇
眼科学   15篇
药学   209篇
中国医学   4篇
肿瘤学   254篇
  2023年   13篇
  2022年   36篇
  2021年   63篇
  2020年   36篇
  2019年   37篇
  2018年   51篇
  2017年   35篇
  2016年   31篇
  2015年   50篇
  2014年   62篇
  2013年   84篇
  2012年   128篇
  2011年   157篇
  2010年   95篇
  2009年   73篇
  2008年   123篇
  2007年   137篇
  2006年   130篇
  2005年   117篇
  2004年   116篇
  2003年   114篇
  2002年   108篇
  2001年   83篇
  2000年   79篇
  1999年   76篇
  1998年   30篇
  1997年   26篇
  1996年   19篇
  1995年   18篇
  1994年   19篇
  1993年   13篇
  1992年   49篇
  1991年   45篇
  1990年   45篇
  1989年   55篇
  1988年   47篇
  1987年   47篇
  1986年   46篇
  1985年   41篇
  1984年   35篇
  1983年   20篇
  1982年   13篇
  1979年   26篇
  1978年   14篇
  1977年   20篇
  1972年   13篇
  1971年   11篇
  1969年   11篇
  1968年   12篇
  1966年   12篇
排序方式: 共有2788条查询结果,搜索用时 15 毫秒
31.
Phenotypic modulation in lipocytes in experimental liver fibrosis   总被引:9,自引:0,他引:9  
The presence of a-smooth muscle actin (smA)-positive cells has recently been reported in the fibrotic liver. Lipocytes have been considered to play important roles in hepatic fibrosis. However, the relation of the a-smA-positive cells and lipocytes has not been determined. The biological implication of a-smA expression remains unknown. To study these questions, we carried out double immunofluorescent staining of a-smA and desmin (a marker for lipocytes), or a-smA and collagen, and double immunohistochemical staining of a-smA and 5-bromo-2'-deoxyuridine (BrdUrd) in carbon tetrachloride-induced fibrotic rat livers. In normal and control livers, a-smA-positive cells were not seen in the lobules, whereas scattered desmin-positive cells were present. With the development of hepatic fibrosis, a-smA was expressed only in a portion of desmin-positive cells located predominantly around collagen bundles. A number of a-smA-positive cells in the lobules were labelled with BrdUrd. These results suggest phenotypic modulation in lipocytes and differentiation of lipocytes towards myofibroblast-like cells, since a-smA is expressed with desmin in myofibroblasts in scar tissue. The expression of a-smA may be related to events of the fibrotic process, such as tissue contraction or fibrogenesis per se.  相似文献   
32.
BACKGROUND: Most children with anaphylaxis to measles, mumps, and rubella vaccines had shown sensitivity to bovine gelatin that was included in the vaccines. Recently, it was found that bovine type I collagen, which is the main content in the gelatin, is a major allergen in bovine gelatin allergy. Fish meat and skin also contain type I collagen. OBJECTIVE: The present study was designed to investigate IgE antibody to fish gelatin in children with fish allergy. METHODS: Serum samples were taken from patients in 3 groups: (1) 10 patients with fish allergy and specific IgE to fish meat; (2) two patients with allergies to both fish meat and bovine gelatin and specific IgE to fish meat and bovine gelatin; and (3) 15 patients with atopic dermatitis and specific IgE to fish meat. Various fish gelatins (type I collagen) were prepared from fish skin. IgE antibody to fish gelatin was analyzed by using ELISA and immunoblotting. RESULTS: Of 10 patients with fish allergy, 3 had specific IgE to fish gelatin. Of two patients with fish allergy and bovine gelatin allergy, all had specific IgE to fish gelatin. Of 15 patients with atopic dermatitis and specific IgE to fish meat, 5 had specific IgE to fish gelatin. Furthermore, IgE from pooled serum of the patients reacted with both the alpha1 and alpha2 chains of fish type I collagen in immunoblots. There is cross-reactivity among gelatins from various fishes, but there is little cross-reactivity between fish and bovine gelatins. CONCLUSION: Some fish-sensitive patients possessed IgE antibody to fish gelatin. Fish gelatin (type I collagen) might be an allergen in subjects with fish allergy.  相似文献   
33.
The efficacy of various currcntly available therapeutic strategies for bladder cancer is not always suffcient, especially for the advanced disease, recurrent superficial cancer, and treatment-resistant carcinoma in situ. Advances in genetic and molecular biology have led to novel approaches for cancer treatment. Gene therapy is currently one of the most promising strategies against various malignancies, and several clinical trials have been approved worldwide. Various strategies for modulating the genetic state have been applied in bladder cancer treatment, and encouraging results have been demonstrated both in vitro and in vivo. Although the therapeutic genes work dramatically when the transgenes are effectively expressed in the targeted cells, however, a sufficient rate of transduction cannot always be achieved. The most significant obstacle for clinical application of cancer gene therapy might be the method for sufficient delivery and expression of the therapeutic genes. Bladder is an easily accessible organ because of its anatomy; however, a glycosaminoglycan (GAG) layer on the bladder mucosa may protect integration of exo-delivered genetic vectors. Various strategies are applied for improving the transduction efficacy of the therapeutic genes into the bladder cancer cells. These strategies include the modification of adenoviral fibers, cotransduction of the materials for enhancing the viral infectivity, and disruption of the GAG layer. Recent advances in the field of gene therapy for bladder cancer are briefly summarized in this review.  相似文献   
34.
Cellular immuno-PCR. Detection of a carbohydrate tumor marker.   总被引:4,自引:0,他引:4       下载免费PDF全文
Carbohydrate tumor-antigens are important tumor markers for diagnosis and functional characteristics of human cancer cells. Detection of these carbohydrate tumor antigens on metastatic cancer cells in blood is a difficult task. We developed a highly sensitive method to detect a cell surface carbohydrate antigen using a hybrid technology referred to as cellular immuno-PCR. This technique uses the human monoclonal antibody (HumAb) L612, specific to a tumor-related antigen (ganglioside) GM3 that is expressed on the cell surface of human tumor cells and not normal cells. L612 coupled to a DNA oligonucleotide for exponential amplification by DNA polymerase chain reaction (PCR) can be used to enhance the detection signal. The DNA-HumAb conjugate was assessed for detection of a small number of human cancer cells after PCR amplification and Southern blot analysis. To assess the assay specificity human melanoma and other cancer cell lines, as well as healthy donor and melanoma patients, bloods were assessed. Cellular immuno-PCR requires < 1 ng/ml DNA-HumAb complex and was shown to have a detection level of < 10 cells in titration studies in which melanoma cells were diluted in 2 million healthy donor peripheral blood lymphocytes. The assay was shown to be very sensitive and could detect low levels of GM3 antigen expression by tumor cells. This novel approach for detecting a carbohydrate tumor antigen on tumor cells in blood provides a potential useful clinicopathological assay.  相似文献   
35.
Spinocerebellar ataxia 27 (SCA27) is an autosomal dominant SCA caused by variants in the fibroblast growth factor 14 (FGF14) gene. We examined a Japanese SCA patient whose deceased father also suffered from SCA. The patient was a 63-year-old male. He graduated from junior high school but received no further education. The predominant complaint was slowly progressive dysarthria and gait disturbance, which appeared at age 47. He showed pathological saccadic dysmetria, saccadic intrusions into smooth pursuit eye movements, dysarthria, and limb and truncal ataxia. His gait was wide-based but he did not require a walking stick. Limb muscle strength was intact. Deep tendon reflexes were normal or slightly reduced. Pathological reflexes were absent. He demonstrated mildly impaired vibration sense in the lower limbs. There was no urinary dysfunction. Brain MRI showed cerebellar atrophy without brainstem involvement. We first confirmed the absence of repeat expansion in genes known to be responsible for SCAs 1–3, 6–8, 10, 12, 17, 36 and dentatorubral-pallidoluysian atrophy. By exome analysis, we identified a novel heterozygous variant (NM_004115, c.529A>T; Lys177X) in exon 4 of the FGF14 gene. This variant is expected to generate a truncated FGF14 protein lacking the heparin binding sites, those are likely to modify the activity of FGF14. We confirmed the absence of the variant in 502 healthy Japanese individuals by Sanger sequencing. There is no record of the variant in public databases. We conclude that the novel variation in FGF14 is causative for SCA27 in this patient.  相似文献   
36.
37.
In this paper a so-called "supralethal dose phenomenon" is reported. Two groups of patients, all of whom were carrying proved squamous cell carcinoma of the same clinical stage in their maxillary sinuses, were compared after radiotherapy in our department. The radiotherapies applied to the two groups were very similar in terms of fraction number, treatment period, dose distribution and immobilization technique, but differed in dose, i.e., 5,500 cGy for one group of 9 patients and 5,750 cGy for the other group of 20 patients. The five-year survival rates of the two groups were 8/9 and 10/20, respectively, and the difference was statistically significant (p less than 0.05). All patients were observed for at least five years. Except for tumor stage, the status of the patients in the two groups, including primary site of the tumor in the sinus, patients' age and cause of death for the failed cases, are also discussed in detail.  相似文献   
38.
Energy drinks containing significant quantities of caffeine, taurine and sugar are increasingly consumed, particularly by adolescents and young adults. The putative effects of chronic ingestion of either standard energy drink, MotherTM (ED), or its sugar-free formulation (sfED) on metabolic syndrome were determined in wild-type C57BL/6J mice, in comparison to a soft drink, Coca-Cola (SD), a Western-styled diet enriched in saturated fatty acids (SFA), and a combination of SFA + ED. Following 13 weeks of intervention, mice treated with ED were hyperglycaemic and hypertriglyceridaemic, indicating higher triglyceride glucose index, which was similar to the mice maintained on SD. Surprisingly, the mice maintained on sfED also showed signs of insulin resistance with hyperglycaemia, hypertriglyceridaemia, and greater triglyceride glucose index, comparable to the ED group mice. In addition, the ED mice had greater adiposity primarily due to the increase in white adipose tissue, although the body weight was comparable to the control mice receiving only water. The mice maintained on SFA diet exhibited significantly greater weight gain, body fat, cholesterol and insulin, whilst blood glucose and triglyceride concentrations remained comparable to the control mice. Collectively, these data suggest that the consumption of both standard and sugar-free forms of energy drinks induces metabolic syndrome, particularly insulin resistance.  相似文献   
39.
Hanganutziu-Deicher (H-D) antigen is classified as a heterophile antigen and chemically defined as a glycoconjugate which contains N-glycolylneuraminic acid. H-D antigens are absent from normal human tissues, but can be expressed on a variety of human malignant cells, including melanoma. Natural anti-H-D antibodies have been detected in man with and without malignancies, but in this study when the level of antibody was compared between healthy adults and patients with melanoma, elevated anti-H-D antibody levels were found more frequently in melanoma patients for both IgM (p = 0.0001) and IgG (p = 0.0001). The present study was designed to evaluate the significance of the H-D antigen-antibody system in melanoma suppression. Sera from melanoma patients containing anti-H-D antibody reacted strongly to H-D antigen expressed on melanoma by means of flow cytometry. In a complement-dependent cytotoxicity assay this antibody killed melanoma cells in vitro. In vivo significance of the antibody was assessed by evaluating the relationship between the antibody levels and the clinical course in patients with stage II melanoma. Antibody levels were measured by enzyme-linked immunosorbent assay using a H-D glycoprotein antigen isolated from bovine erythrocytes. A significantly higher level of IgG (p = 0.0640) and IgM (p = 0.0644) anti-H-D antibody was demonstrated in those patients who were free of disease more than 5 years after surgery than in those who relapsed within 2 years. This study provides a rational basis for immunotherapy targeting H-D antigen in human melanoma.  相似文献   
40.
OBJECTIVE: The purpose of this study is to show and analyze the CT appearance of pseudolesions of the liver caused by rib compression and to discuss the possible mechanism on the basis of findings of incremental dynamic CT, CT during arterial portography, and CT hepatic arteriography. CONCLUSION: Focal compression of the liver caused by curved ribs can cause transient focal diminishment of portal venous perfusion without significantly altering hepatic arterial perfusion. Such diminishment may be observed as low-density areas on the early phase of incremental dynamic CT.  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