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   542篇
  免费   29篇
儿科学   12篇
妇产科学   21篇
基础医学   158篇
口腔科学   13篇
临床医学   27篇
内科学   124篇
皮肤病学   5篇
神经病学   17篇
特种医学   2篇
外科学   66篇
综合类   7篇
预防医学   30篇
眼科学   9篇
药学   20篇
中国医学   2篇
肿瘤学   58篇
  2022年   7篇
  2021年   8篇
  2020年   4篇
  2019年   13篇
  2018年   11篇
  2017年   3篇
  2016年   14篇
  2015年   8篇
  2014年   13篇
  2013年   29篇
  2012年   32篇
  2011年   34篇
  2010年   24篇
  2009年   15篇
  2008年   25篇
  2007年   18篇
  2006年   20篇
  2005年   18篇
  2004年   13篇
  2003年   19篇
  2002年   11篇
  2001年   5篇
  2000年   21篇
  1999年   20篇
  1998年   6篇
  1996年   4篇
  1994年   2篇
  1993年   4篇
  1992年   16篇
  1991年   9篇
  1990年   11篇
  1989年   8篇
  1988年   17篇
  1987年   14篇
  1986年   11篇
  1985年   9篇
  1984年   10篇
  1983年   3篇
  1982年   2篇
  1981年   4篇
  1980年   5篇
  1979年   8篇
  1978年   6篇
  1977年   3篇
  1976年   7篇
  1975年   3篇
  1974年   8篇
  1973年   4篇
  1972年   2篇
  1970年   2篇
排序方式: 共有571条查询结果,搜索用时 16 毫秒
91.
Lobular intraepithelial neoplasia Grade 3 (LIN3) is a recently recognized variant of intraepithelial lobular neoplasia (LIN) of the breast composed of either uniform, generally small cells with massive lobular distension, pleomorphic cells, signet‐ring cells, or any cell type with necrosis. In contrast to classic forms of LIN, there is no consensus on therapeutic strategies for LIN3. In part this is due to the paucity of molecular data that could assist in defining the relationship of LIN3 to classic LIN and carcinomas. In this study we have employed array comparative genomic hybridization to determine the patterns of chromosomal aberrations in nine LIN3 lesions. By comparison to array CGH data of 13 classic LIN lesions, we demonstrate that classic LIN and LIN3 share several recurrent changes, in particular gains of 1q and losses of 16q. Both aberrations are known to appear early in tumorigenesis and to be associated with good prognosis. However, apart from this overlap, there were a number of karyotypic features that were observed exclusively in LIN3. Clearly, this lesion was characterized by a significantly higher number of DNA copy number changes (9 vs. 31 on average), a considerable complexity of chromosomal rearrangements with more than 16 breakpoints in one chromosome and overlapping high copy amplifications encompassing a number of known oncogenes. Our data suggest that, at the genetic level, LIN3 represents a highly advanced lesion with considerable resemblance to carcinomas and, therefore, might represent the transition state from an intraepithelial neoplasm to breast carcinoma. © 2010 Wiley‐Liss, Inc.  相似文献   
92.
To measure discrepancies in diagnoses and recommendations impacting management of proliferative lesions of the breast, a questionnaire of five problem scenarios was distributed among over 300 practicing pathologists. Of the 230 respondents, 56.5% considered a partial cribriform proliferation within a duct adjacent to unequivocal ductal carcinoma in situ (DCIS) as atypical ductal hyperplasia (ADH), 37.7% of whom recommended reexcision if it were at a resection margin. Of the 43.5% who diagnosed the partially involved duct as DCIS, 28.0% would not recommend reexcision if the lesion were at a margin. When only five ducts had a partial cribriform proliferation, 35.7% considered it as DCIS, while if ≥20 ducts were so involved, this figure rose to 60.4%. When one duct with a complete cribriform pattern measured 0.5, 1.5, or 4 mm, a diagnosis of DCIS was made by 22.6, 31.3, and 94.8%, respectively. When multiple ducts with flat epithelial atypia were at a margin, 20.9% recommended reexcision. Much of these discrepancies arise from the artificial separation of ADH and low-grade DCIS and emphasize the need for combining these two under the umbrella designation of ductal intraepithelial neoplasia grade 1 (DIN 1) to diminish the impact of different terminologies applied to biologically similar lesions.  相似文献   
93.
Anemia of spaceflight   总被引:2,自引:0,他引:2  
Tavassoli  M 《Blood》1982,60(5):1059-1067
A consistent deficit in the red cell mass has been observed during both the American and Soviet orbital space flights and is sometimes referred to as "astronaut anemia." This may be associated with a reduction in plasma volume so that the hematocrit and the hemoglobin concentration remain unchanged. During the Gemini program, the hypobaric hyperoxic atmosphere of the spacecraft led to oxidative injury to the red cells, causing hemolysis. Thus, the atmosphere proved to be, in part, responsible for the deficit. However, a similar deficit of a lesser magnitude was again observed in subsequent flights with normal ambient PO2 as well as in the Soviet flights in which an atmosphere essentially of see level air is used. The cause of this deficit seems to be suppression of erythropoiesis, as indicated by reticulocytopenia and erythroid hypoplasia of the marrow. No suppression of erythropoiesis has been observed in ground-based experiments carried out under almost identical conditions. Thus, the suppression of erythropoiesis is thought to be related to weightlessness. The reason for the suppression is not known but may be related to total inhibition of bone formation.  相似文献   
94.
The availability of safe and effective factor replacement therapies, in persons with haemophilia (PWH), has in some countries answered the basic need for treatment of these patients. The findings suggest that adult patients who have always been on prophylaxis reported significantly better physical functioning, and thus better quality of life. This study is designed to evaluate the QoL in adult PWH, by focusing on social determinants of QoL and their relationship with health‐related dimensions, in Tabriz, Iran. The survey instrument was a self‐report 36 items questionnaire, ‘A36 Hemofilia – QoL’, which is a disease‐specific questionnaire for the assessment of the health‐related QoL in adults living with haemophilia. A total of 100 haemophilia A and B patients, aged over 17 years participated in this study within 1 year. QoL total score was 71.88 (±26.89 SD). Patients who treat in our Hemophilia Treatment Center, had better QoL score (P = 0.000), and education has a significant impact on the social aspects of QoL (P = 0.18). The QoL was very poor in urban area in contrast to patients who lived in the city (54.45 vs. 74.21 respectively). Single patients have a better QoL than married patients (76.56 vs. 68.50 respectively). Our results showed that low education and lack of awareness of the diseases among PWH lead to reduce of QoL and more disease complications. More and wider treatment and psychological care for improving quality of life of these patients are seriously recommended.  相似文献   
95.
The nature of contact between endothelial cells in rat marrow sinuses was studied. Colloidal lanthanum permeated freely into the interendothelial space. Moreover, using freeze-fracture technique, we failed to show junctional structures where these endothelial cells came into contact. With thin sectioning electron microscopy, we observed occasional submembranous densities but the interendothelial distance measured 20 nm and no membrane fusion was seen. Absence of tight junctions between endothelial cells of marrow sinuses may serve a function in marrow cell egress by permitting these cells to slide over each other, thereby changing the luminal size. Within the fixed volume of marrow, an increase in luminal size results in displacement of haemopoietic cells into the lumen.  相似文献   
96.
Bone marrow transplantation is done by introducing a source of hemopoietic stem cells into general circulation in anticipation of their recognition and selective lodging into the bone marrow. We tested the hypothesis that the molecular basis of this recognition is by means of a lectin-carbohydrate interaction. We synthesized a number of neoglycoproteins by covalently binding pyranose derivatives of various monosaccharides to bovine serum albumin (BSA). These reagents and the galactosyl-terminating glycoprotein asialofetuin were used to inhibit engraftment of intravenously transplanted marrow cells into lethally irradiated mice. In splenectomized mice, in whom engraftment occurs only in the bone marrow, galactosyl-BSA, mannosyl-BSA, and asialofetuin but not fucosyl-BSA inhibited homing of transplanted cells. Both the survival and cellular content of marrow, including hemopoietic stem cells and granulocyte-macrophage progenitors, were reduced. In nonsplenectomized mice, in whom engraftment occurs in both spleen and marrow, the reagents did not inhibit splenic homing. Both the survival and cellular content of spleen, including hemopoietic stem cells and granulocyte-macrophage progenitors, were similar to those of the control group. But even in this group, marrow homing of transplanted cells was inhibited by these reagents. We conclude that the recognition and homing of intravenously transplanted hemopoietic cells by marrow, but not by spleen, occurs by means of a recognition system with galactosyl and mannosyl specificities.  相似文献   
97.
98.
This topic review discusses the evolving clinical challenges associated with the implementation of electronic personal health records (PHR) that are fully integrated with electronic medical records (EMR). The benefits of facilitating patient access to the EMR through web-based, PHR-portals may be substantial; foremost is the potential to enhance the flow of information between patient and healthcare practitioner. The benefits of improved communication and transparency of care are presumed to be a reduction in clinical errors, increased quality of care, better patient-management of disease, and better disease and symptom comprehension. Yet PHR databases allow patients open access to newly-acquired clinical data without the benefit of concurrent expert clinical interpretation, and therefore may create the potential for greater patient distress and uncertainty. With specific attention to neuro-oncology patients, this review focuses on the developing conflicts and consequences associated with the use of a PHR that parallels data acquisition of the EMR in real-time. We conclude with a discussion of recommendations for implementing fully-integrated PHR for neuro-oncology patients.  相似文献   
99.
This study is an ultrastructural analysis of hemopoiesis in S1/S1d anemic mice. The anemia in this strain is caused by a defect in hemopoietic microenvironment which fails to support hemopoiesis. Marrow cellularity is reduced and vascular channels are dilated. Coverage of sinus endothelium by adventitial cells is nearly twice as in normal mice, suggesting a reduced rate of cell traffic into the circulation. Central macrophages are small with little or no interdigitation with erythroid cells and no crystalloid inclusions as seen in normal littermates. The findings suggest that a fundamental abnormality in the central macrophage may be responsible for the defect in hemopoietic microenvironment.  相似文献   
100.
Granular cell tumor. Clinical spectrum of the benign and malignant entity   总被引:2,自引:0,他引:2  
T Khansur  L Balducci  M Tavassoli 《Cancer》1987,60(2):220-222
The clinical records of all patients with granular cell tumor seen at our institution over a 20-year period were reviewed. Three patients with malignant, and 37 with benign tumor, were identified. Eleven patients had multiple benign lesions. Three had a history of familial occurrence. Clinical and pathologic features and the management of this nebulous entity, in both its benign and malignant forms, are reviewed and discussed.  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