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   3568篇
  免费   157篇
  国内免费   19篇
耳鼻咽喉   57篇
儿科学   29篇
妇产科学   21篇
基础医学   427篇
口腔科学   62篇
临床医学   199篇
内科学   914篇
皮肤病学   154篇
神经病学   215篇
特种医学   305篇
外科学   597篇
综合类   15篇
预防医学   56篇
眼科学   15篇
药学   176篇
中国医学   13篇
肿瘤学   489篇
  2023年   17篇
  2022年   38篇
  2021年   70篇
  2020年   49篇
  2019年   68篇
  2018年   71篇
  2017年   75篇
  2016年   103篇
  2015年   72篇
  2014年   115篇
  2013年   142篇
  2012年   195篇
  2011年   231篇
  2010年   107篇
  2009年   99篇
  2008年   195篇
  2007年   241篇
  2006年   210篇
  2005年   218篇
  2004年   215篇
  2003年   219篇
  2002年   202篇
  2001年   85篇
  2000年   48篇
  1999年   66篇
  1998年   44篇
  1997年   48篇
  1996年   40篇
  1995年   32篇
  1994年   25篇
  1993年   22篇
  1992年   35篇
  1991年   21篇
  1990年   26篇
  1989年   37篇
  1988年   19篇
  1987年   30篇
  1986年   19篇
  1985年   15篇
  1984年   10篇
  1983年   15篇
  1982年   12篇
  1981年   9篇
  1979年   9篇
  1975年   10篇
  1974年   9篇
  1972年   9篇
  1970年   10篇
  1969年   12篇
  1968年   9篇
排序方式: 共有3744条查询结果,搜索用时 15 毫秒
61.
We determined the presence of antibodies to the heat-shock protein hsp73 (anti-hsp73) in 57 serum samples from patients with localized scleroderma using an enzyme-linked immunosorbent assay (ELISA). In addition, 30 samples from healthy individuals, 30 from patients systemic lupus erythematosus (SLE) and 32 from patients with systemic sclerosis were assessed. IgG and/or IgM anti-hsp73 antibodies were detected in 33% (19/57) of the patients with localized scleroderma. Among the three subtypes of localized scleroderma, generalized morphoea showed the highest incidence of anti-hsp73 antibodies (40%, 6/15). IgG and/or IgM anti-hsp73 antibodies were also detected in 9/30 samples (30%) from patients with SLE and in 13/32 samples (41%) from patients with systemic sclerosis, while the samples from the healthy controls were all negative for anti-hsp73. By immunoblotting, specific binding of antibodies to hsp73 was confirmed with representative serum samples that were positive for anti-hsp73 in the ELISA. Our findings indicate that the presence of anti-hsp73 is an additional immunological abnormality in localized scleroderma.  相似文献   
62.
Systemic sclerosis (SSc) is an autoimmune systemic connective tissue disorder characterized by sclerotic change of the skin and multiple internal organs. Although the pathogenesis of this disorder is still unknown, overproduction of extracellular matrix proteins, including collagens and fibronectin, and aberrant immune activation may be involved in the mechanism. Interleukin (IL)‐1 is one of the key regulators of inflammatory response. IL‐1 is also involved in regulating connective tissue remodeling and cellular differentiation of epithelial and ectodermal cells. There are three major members of the IL‐1 family: IL‐1α, IL‐1β and IL‐1 receptor antagonist. IL‐1α was first described as a factor derived from keratinocytes that stimulates thymocyte proliferation. IL‐1α plays a crucial role in procollagen production by fibroblasts derived from patients with SSc. The present study was undertaken to investigate the serum levels of IL‐1α in patients with SSc. Serum samples were obtained from 66 Japanese patients with SSc and 19 healthy controls. Levels of serum IL‐1α were measured with a specific enzyme‐linked immunoassay kit. Mean serum levels were significantly higher in SSc patients than in those healthy control subjects. Moreover, contracture of phalanges was found at a significantly lower prevalence in SSc patients with elevated serum IL‐1α levels than those with normal levels. These results suggest that IL‐1α may play a role in the pathogenesis of SSc.  相似文献   
63.
Localized scleroderma (LSc), a connective tissue disorder restricted to the skin and subcutaneous tissue, is characterized by skin fibrosis due to an excessive deposition of types I collagen. The mechanism of such fibrosis is still unknown, but epigenetics may play some roles in the excessive collagen expression. In the present study, we investigated the mechanism of fibrosis seen in LSc, focusing on microRNA (miRNA). miRNA expression was determined by PCR array, real-time PCR, and in situ hybridization. The function of miRNA was evaluated using specific inhibitor. Immunoblotting was performed to detect α2(I) collagen protein. PCR array analysis using tissue miRNA demonstrated miR-7 level was significantly decreased in LSc skin as well as keloid tissue compared to normal skin in vivo. In situ hybridization also showed miR-7 expression in dermal fibroblasts was decreased in LSc dermis. The transfection of specific inhibitor for miR-7 into cultured normal dermal fibroblasts resulted in the up-regulation of α2(I) collagen protein in vitro. Also, the serum levels of miR-7 were significantly decreased in LSc patients compared with healthy controls, but serum miR-29a levels not. Systemic or local down-regulation of miR-7 may contribute to the pathogenesis of LSc via the overexpression of α2(I) collagen, and serum miR-7 may be useful as a disease marker. Investigation of the regulatory mechanisms of LSc by miRNA may lead to new treatments by the transfection into the lesional skin of this disease.  相似文献   
64.
Abstract:  Localized scleroderma is a connective tissue disorder that is limited to the skin and subcutaneous tissue. Macrophages have been reported to be particularly activated in patients with skin disease including systemic sclerosis and are potentially important sources for fibrosis-inducing cytokines, such as transforming growth factor β. To clarify the features of immunohistochemical characterization of the immune cell infiltrates in localized scleroderma focusing on macrophages, skin biopsy specimens were analysed by immunohistochemistry. The number of cells stained with monoclonal antibodies, CD68, CD163 and CD204, was calculated. An evident macrophage infiltrate and increased number of alternatively activated macrophages (M2 macrophages) in their fibrotic areas were observed along with their severity of inflammation. This study revealed that alternatively activated macrophages (M2 macrophages) may be a potential source of fibrosis-inducing cytokines in localized scleroderma, and may play a crucial role in the pathogenesis of localized scleroderma.  相似文献   
65.
We report a case of metastatic bladder tumor from gastric cancer, which was difficult to differentiate from urachal tumor preoperatively, especially computed tomographic scan, cystoscopy, and biopsy. A 51-year old man visited our hospital with the chief complaint of asymptomatic gross hematuria. He had received subtotal gastrectomy for gastric cancer two years earlier. Because the possibility of urachal tumor could not be excluded, en bloc segmental resection of the bladder, the urachus, and the umbilicus was carried out. This case was diagnosed as adenocarcinoma histologically, but it was difficult to determine whether the case was a metastatic bladder tumor from gastric cancer or urachal tumor by the routine staining method. High iron diamine-alcian blue and paradoxical concanavalin A (ConA) stainings were performed, on the surgical specimens of this case and other urachal tumor already diagnosed. In these cases, metastatic bladder tumor could be differentiated from an urachal one by mucohistochemically paradoxical Con A staining. Seventeen cases of metastatic bladder tumor from gastric cancer including our cases were collected from the Japanese literature and reviewed.  相似文献   
66.
Testicular metastasis of multiple myeloma: a case report   总被引:1,自引:0,他引:1  
A 49-year-old man was admitted to our department with the complaint of right scrotal painless swelling in May 1986. The patient had been treated for multiple myeloma since November 1985. Right orchiectomy was performed under the diagnosis of malignant testicular tumor. The right scrotal mass was 5 x 7.5 x 3.5 cm in size. Histological diagnosis was testicular metastasis of multiple myeloma. Testicular metastasis of multiple myeloma is very rare and only 5 cases have been reported in the Japanese literature. The 6 cases including our case with testicular metastasis of multiple myeloma in Japan are reviewed.  相似文献   
67.
Glycogen storage disease type Ia (GSD-Ia; von Gierke disease) is an inherited disorder caused by glucose-6-phosphatase deficiency, and there have been some reports of hepatic tumors in patients with this disease. We report two patients with benign hepatic tumors with GSD-Ia. One is a 19-year-old man who underwent segmentectomy 4 for a focal nodular hyperplasia, and the other is a 31-year-old woman who underwent segmentectomies 3, 5, and 6 for hepatic adenomas. Two significant perioperative complications, resulting from the carbohydrate metabolic disorders, hypoglycemia and metabolic acidosis, occurred in both patients. We managed the metabolic complications successfully by administering a sufficient volume of glucose intravenously. Close perioperative monitoring of blood glucose and lactate concentrations is essential in the perioperative management of patients with GSD-Ia. The intravenous administration of glucose, starting with a smaller dose and then increasing the dose, is adequate management for lactic acidosis with or without hypoglycemia during the perioperative period.  相似文献   
68.
BACKGROUND: We developed a method for reorganizing the mouse small intestine. In the present study, we investigated whether the reorganized small intestine was morphologically and histochemically differentiated. We also evaluated the reorganized small intestine as an in vitro wound healing model. METHODS: Fetal mouse small intestines were dispersed into single cells, which were then cultured to a high density. Newly formed small intestine-like organs on a membrane filter were observed by light and electron microscopy. Alkaline phosphatase (ALPase) activity of the epithelium was analyzed. To evaluate the reorganized small intestine as an in vitro wound healing model, a scalpel was used to cut the reorganized intestine on a membrane, and the healing process was morphologically and immunohistochemically examined. RESULTS: After 6 days in culture, the surface was almost completely coveed with epithelial cells, and villus-like structures were observed. These epithelial cells formed microvilli, and in parallel with this development, ALPase activity of the microvilli increased (from day 4). Twenty-four hours after the cutting, the wound surface was almost completely covered with undifferentiated epithelial cells. The number of acetylated low-density lipoprotein labeled with 1,1,dioctadecyll,3,3,3,3, tetramethyl-indocarbocyanine perchlorate (DiI-Ac-LDL)-positive macrophages increased after cutting. Platelet-derived growth factor (PDGF)-, basic fibroblast growth factor (bFGF)-, matrix metalloproteinase-1 (MMP-1)-positive cells were detected by immunohistochemical staining. CONCLUSIONS: The reorganized small intestine had a morphologically and histochemically differentiated organoid structure, and was useful as an in vitro model for investigating the process of wound healing.  相似文献   
69.
It is well known that sex steroids play important roles in the development of invasive ductal carcinoma (IDC) of the human breast. However, biological significance of sex steroids remains largely unclear in ductal carcinoma in situ (DCIS), regarded as a precursor lesion of IDC, which is partly due to the fact that the intratumoral concentration of sex steroids has not been examined in DCIS. Therefore, in this study, we first examined the intratumoral concentrations of estradiol and 5alpha-dihydrotestosterone (DHT) using liquid chromatography/electrospray tandem mass spectrometry in DCIS. Intratumoral concentrations of both estradiol and DHT were threefold higher in DCIS than non-neoplastic breast tissues and estrogen-producing enzymes (aromatase, steroid sulfatase, and 17beta-hydroxysteroid dehydrogenase type 1 (17betaHSD1)), and androgen-producing enzymes (17betaHSD5 and 5alpha-reductase type 1 (5alphaRed1)) were abundantly expressed in DCIS by real-time PCR and immunohistochemical analyses. The intratumoral concentration of DHT was significantly lower in IDC than DCIS, while the expression of aromatase mRNA in carcinoma cells and intratumoral stromal cells was significantly higher in IDC than those in DCIS. Immunohistochemistry for sex steroid-producing enzymes in DCIS demonstrated that 5alphaRed1 immunoreactivity was positively correlated with Ki-67 labeling index and histological grade and was also associated with an increased risk of recurrence in patients with DCIS examined. Results of our study suggest that intratumoral concentrations of estradiol and DHT are increased in DCIS, which is possibly due to intratumoral production of these steroids. Therefore, estradiol and DHT may play important roles in the development of DCIS of the human breast.  相似文献   
70.
The patient was a 39-year-old woman admitted with complaints of fever, clubbed fingers and arthralgia. A chest roentgenogram and chest computed tomographic scan revealed a mass in the left lower lobe. Transbronchial lung biopsy was performed, and a diagnosis of moderately differentiated adenocarcinoma was made. Physical examination confirmed finger clubbing in both hands. Bone scintigram showed marked accumulation of 99mTc-MDP in the long bones, bones of the elbows, and patellae. These findings yielded a diagnosis of pulmonary hypertrophic osteoarthropathy associated with primary lung cancer in young adult. The patient had fever and disturbance of gait of arthralgia on admission, and was treated with an oral non-steroidal anti-inflammation drug (NSAID). Advanced non small cell lung cancer (clinical stage T2 N3 M1, Stage IV) was then diagnosed. Gefitinib was administered after EGFR mutation was found in the tumor specimen. NSAID therapy alleviated the fever and arthralgia. After starting gefitinib and discontinuing the NSAID, She had kept a remission of rational symptom with cytoreductive effect. The abnormal findings of bone scintigrams subsequently disappeared and the patient's serum ICTP dropped.  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