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   4331篇
  免费   210篇
  国内免费   16篇
耳鼻咽喉   26篇
儿科学   63篇
妇产科学   43篇
基础医学   588篇
口腔科学   189篇
临床医学   289篇
内科学   1122篇
皮肤病学   39篇
神经病学   374篇
特种医学   151篇
外科学   674篇
综合类   22篇
预防医学   90篇
眼科学   86篇
药学   305篇
中国医学   5篇
肿瘤学   491篇
  2023年   19篇
  2022年   39篇
  2021年   64篇
  2020年   36篇
  2019年   54篇
  2018年   63篇
  2017年   41篇
  2016年   65篇
  2015年   64篇
  2014年   107篇
  2013年   148篇
  2012年   201篇
  2011年   212篇
  2010年   117篇
  2009年   116篇
  2008年   191篇
  2007年   231篇
  2006年   192篇
  2005年   182篇
  2004年   192篇
  2003年   185篇
  2002年   173篇
  2001年   120篇
  2000年   136篇
  1999年   133篇
  1998年   64篇
  1997年   47篇
  1996年   41篇
  1995年   40篇
  1994年   38篇
  1993年   28篇
  1992年   125篇
  1991年   110篇
  1990年   118篇
  1989年   85篇
  1988年   80篇
  1987年   103篇
  1986年   105篇
  1985年   86篇
  1984年   46篇
  1983年   47篇
  1981年   19篇
  1979年   45篇
  1978年   19篇
  1977年   21篇
  1976年   22篇
  1975年   18篇
  1973年   23篇
  1972年   21篇
  1969年   18篇
排序方式: 共有4557条查询结果,搜索用时 15 毫秒
131.
Xanthomatous meningioma is an extremely rare variant of meningioma that is characterized histopathologically by the presence of tumor cells with lipid-filled vacuolated cytoplasm. In this report, we describe the fifth documented case of xanthomatous meningioma and review its clinicopathological features. A 76-year-old Japanese male presented with dizziness. Magnetic resonance imaging demonstrated a well-circumscribed tumor in the left parasagittal to frontal region with attachment of the dura mater. Histopathological examination of the resected specimen revealed proliferation of polygonal to spindle cells with eosinophilic cytoplasm and bland round to oval nuclei. Whorl formation and psammomas were scattered, and mitotic figures were rarely seen. A peculiar finding was the presence of extensive xanthomatous change continuing to the above-mentioned typical meningothelial meningioma. These tumor cells had clear vacuolated cytoplasm and bland round to oval nuclei. Immunohistochemically, xanthomatous cells were positive for epithelial membrane antigen. Accordingly, an ultimate diagnosis of xanthomatous meningioma was made. Our clinicopathological analysis revealed that xanthomatous meningioma affects children to young persons or the elderly, and four of five cases were located in the supratentorial region. Although the detailed mechanism underlying the xanthomatous change has not been clarified, this change is thought to result from a metabolic abnormality of the neoplastic meningothelial cells. Further, xanthomatous change has also been reported in atypical and anaplastic meningiomas. Therefore, it is important to recognize that xanthomatous change can occur in meningiomas, and to avoid misidentifying these cells as macrophages.  相似文献   
132.
Follicular mucinosis is recognized as one of the histopathological reaction patterns characterized by the accumulation of mucin within follicular epithelium. It is induced by various causes including inflammatory diseases, and more than half of the cases are associated with malignant lymphoma, mainly mycosis fungoides. Herein, we describe the third documented case of adult T-cell leukemia/lymphoma (ATLL) accompanying follicular mucinosis. A 72-year-old Japanese male presented with persistent erythema in his arm and neck. Laboratory tests demonstrated positivity for human T-cell leukemia virus (HTLV)-1 antibodies. Histopathological study of the biopsy specimen from the neck revealed superficial perivascular, nodular, and intrafollicular lymphocytic infiltrations. These lymphocytes were small- to medium-sized and had convoluted nuclei. Mucoid material deposition was observed within the hair follicles, and it was digested by hyaluronidase. Immunohistochemically, these lymphocytes were positive for CD3, CD4, CD25, and Foxp3. Accordingly, an ultimate diagnosis of ATLL accompanying follicular mucinosis was made. The skin is the most common extralymphatic site of involvement of ATLL. The present case clearly demonstrated that albeit extremely rare, ATLL can cause follicular mucinosis. Therefore, ATLL should be included in the differential diagnostic consideration of follicular mucinosis.  相似文献   
133.
134.
The outcomes of organ transplantation have improved due to better immunosuppressive drugs, surgical techniques, and management of complications. However, ischemia-reperfusion injury remains a challenge affecting graft survival. In this study, we employed injection of a protein transduction domain (PTD) to inhibit the c-Jun NH2-terminal kinase (JNK) pathway thereby attenuating ischemia-reperfusion injury in a porcine model. The PTD-JNK inhibitor (JNKI) was administered into the renal artery, allowing it to be taken into various elements including vascular endothelial cells by endocytosis via the PTD. Serum creatinine and blood urea nitrogen concentrations were lower among PTD-JNKI than controls. In addition, renal tissue blood flow was maintained in the PTD-JNKI group, resulting in less tissue injury and fewer apoptotic cells. These results suggested that the PTD technique improved renal transplantation outcomes.  相似文献   
135.
136.

Background

We aimed to identify a noninvasive predictor of portal venous pressure (PVP).

Methods

We directly measured the PVP in 40 consecutive patients who underwent direct percutaneous transhepatic portal vein puncture as part of the therapeutic management for liver diseases, and we evaluated the association of the PVP with noninvasive clinical parameters. The backgrounds of the liver were normal in 13 patients, chronic hepatitis in 17, and liver cirrhosis in ten.

Results

The mean PVP was 202 ± 114 mmH2O. In a multivariate linear regression analysis, the serum bile acid level and splenic volume showed independent positive correlations with the PVP (P < 0.001 and 0.002, respectively). The formula for estimating PVP was identified as follows: PVP (mmH2O) = serum bile acid (??mol/L) × 2.593 + splenic volume (cm3) × 0.416 + 65.929 (R 2 = 0.698). In a receiver operating characteristic (ROC) analysis, the AUC values of serum bile acid and splenic volume at a PVP of 200 mmH2O were 0.909 and 0.758, respectively. However, the AUC values of serum bile acid and splenic volume at a PVP of 250 mmH2O were 0.792 and 0.926, respectively, suggesting that the serum bile acid level and splenic volume are sensitive predictors of early and advanced portal hypertension, respectively.

Conclusions

Combined measurements of the serum bile acid level and splenic volume may be useful to noninvasively assess the PVP prior to further invasive procedures.  相似文献   
137.
Background and Aim: Type 1 autoimmune pancreatitis (AIP) is characterized by the increase of serum immunoglobulin (Ig)G4 and abundant IgG4 plasma cell infiltration in the pancreas and various extrapancreatic lesions (EPL), which are proposed as IgG4‐related disease. We assessed the correlation between serum IgG4 and the number of EPL, and the association between serum IgG4 and the distribution of EPL in type 1 AIP patients. Methods: Serum IgG4 was measured in 35 type 1 AIP patients and 71 non‐AIP patients. The clinical characteristics and distribution of eight EPL were determined in 35 type 1 AIP patients. Results: Serum IgG4 in type 1 AIP was significantly higher than in non‐AIP (P < 0.001). A total of 33 patients had EPL among 35 patients with type 1 AIP (94.3%). There was a significant correlation between serum IgG4 and the number of EPL (ρ = 0.75, P < 0.001). Further, to assess the association between serum IgG4 and the distribution of EPL, type 1 AIP patients were divided into two groups: as abdominal localized EPL and systemic EPL. Both serum IgG4 and total numbers of EPL in systemic EPL were remarkably higher than those in abdominal localized EPL. Serum IgG4 cut‐off value was 346 mg/dL to distinguish between abdominal localized EPL and systemic EPL according to the receiver–operator characteristic curve data. Conclusions: Our findings indicated that serum IgG4 was useful in both the diagnosis of type 1 AIP and the detection of systemic EPL. Our finding may help the concept and diagnostic criteria of IgG4‐related disease with type 1 AIP.  相似文献   
138.
The T315I BCR-ABL mutation in chronic myelogenous leukemia (CML) patients is responsible for up to 20% of all clinically observed resistance. This mutation confers resistance not only to imatinib, but also to second-generation BCR-ABL tyrosine kinases, such as nilotinib and dasatinib. A number of strategies have been implemented to overcome this resistance, but allogeneic stem cell transplantation remains the only established therapeutic option for a cure. A 61-year-old male was diagnosed with Philadelphia chromosome-positive chronic-phase CML in 2002. He was initially treated with imatinib and complete cytogenetic response (CCyR) was achieved 12 months later. However, after 18 months, a loss of CCyR was observed and a molecular study at 24 months revealed a T315I mutation of the BCR-ABL gene. At 30 months, imatinib/interferon-alfa (IFNα) combination therapy was initiated in an effort to overcome the resistance. Thirty months later, he re-achieved CCyR, and the T315I BCR-ABL mutation disappeared at 51 months. To our knowledge, this is the first case report showing the effectiveness of imatinib/IFNα combination therapy for CML patients bearing the T315I BCR-ABL mutation.  相似文献   
139.

Background

Quality of life (QOL) is a concern for patients with lumbar spinal stenosis (LSS). In this study, QOL was examined using the 5-item EuroQol (EQ-5D).

Methods

QOL and activities of daily living (ADL) were surveyed for 91 patients who visited 18 medical institutions in our prefecture and were diagnosed with LSS-associated intermittent claudication. A second survey was performed after ≥6 weeks for 79 of the subjects to evaluate therapy with limaprost (an oral prostaglandin E1 derivative) or etodolac (an NSAID). Symptoms, maximum walking time, QOL, ADL items, and relationships among these variables were investigated for all 91 patients. Leg pain, leg numbness, and low back pain while walking were surveyed by use of VAS scores (0–100).

Results

Leg pain, leg numbness, and low back pain while walking (VAS ≥25) were present in 83.5, 62.6, and 54.9 % of the patients in the first survey, and approximately half of the patients had a maximum walking time <15 min. The mean EQ-5D utility value for QOL was 0.59 ± 0.12. This value was significantly associated with maximum walking time (p = 0.030) based on classification of patients into groups with walking times <7.5, 7.5–15, 15–30, and >30 min, showing that maximum walking time affected health-related QOL. Of the 79 patients who completed the second survey, 56 had taken limaprost and 23 (control group) had received etodolac. Limaprost improved possible walking time, reduced ADL interference, and significantly increased the EQ-5D utility score, whereas no significant changes occurred in the control group. Maximum walking time was prolonged by ≥10 min and the EQ-5D utility value was improved by ≥0.1 points in significantly more patients in the limaprost group than in the control group.

Conclusion

According to the findings of this survey, at an average of 8 weeks after administration limaprost improved symptoms, QOL, and ADL in LSS patients whereas treatment with an NSAID reduced pain but did not have any other effects.  相似文献   
140.

Background

Minimally invasive esophagectomy (MIE) in the prone position typically includes thoracoscopic mediastinal dissection and laparoscopic gastric tube construction, followed by esophagogastric anastomosis in the neck. We introduced an intrathoracic esophagogastric anastomosis using linear staplers.

Technique

The lower mediastinal dissection and the gastric tube construction are done in the laparoscopic part of the operation. The esophagus is transected at the cranial level of the aortic arch after the completion of the upper mediastinal lymph node dissection in the prone position. The excess length of the gastric tube is sacrificed before making the anastomosis. Side-to-side esophagogastric anastomosis is performed using a 35-mm endoscopic linear stapler. The entry hole is closed with hand suturing using the posterior and the axillary port.

Results

Twenty-six patients with middle or lower esophageal tumor underwent MIE with an intrathoracic anastomosis. The mean thoracoscopic procedure time was 302 min. One patient had an anastomotic leakage, which was successfully managed with drainage. There has been no anastomotic stenosis. Pneumonia was observed in two patients. There was no mortality.

Conclusions

MIE with an intrathoracic linear-stapled anastomosis with the patient in the prone position is safe and feasible.  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