首页 | 官方网站   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   1372篇
  免费   149篇
  国内免费   7篇
医药卫生   1528篇
  2022年   6篇
  2021年   20篇
  2020年   13篇
  2019年   28篇
  2018年   41篇
  2017年   26篇
  2016年   30篇
  2015年   22篇
  2014年   43篇
  2013年   28篇
  2012年   51篇
  2011年   45篇
  2010年   41篇
  2009年   43篇
  2008年   51篇
  2007年   53篇
  2006年   64篇
  2005年   44篇
  2004年   49篇
  2003年   48篇
  2002年   44篇
  2001年   35篇
  2000年   34篇
  1999年   38篇
  1998年   39篇
  1997年   56篇
  1996年   55篇
  1995年   45篇
  1994年   41篇
  1993年   38篇
  1992年   33篇
  1991年   18篇
  1990年   24篇
  1989年   18篇
  1988年   28篇
  1987年   23篇
  1986年   27篇
  1985年   19篇
  1984年   18篇
  1983年   15篇
  1982年   17篇
  1981年   16篇
  1980年   8篇
  1979年   7篇
  1978年   5篇
  1977年   8篇
  1976年   15篇
  1975年   9篇
  1973年   6篇
  1968年   5篇
排序方式: 共有1528条查询结果,搜索用时 15 毫秒
91.
The author believes that professional advice given the parents of a mongoloid infant determines their initial decision on institutionalization. Multidisciplinary counseling by the health team can help parents decide on a course of action that will prove satisfactory in the long run. Consultation should include health t e r n efforts to help parents work through the mourning process and presentation of a) an objective, comprehensive view of the child's condition, b) information on integrating a mongoloid into the family unit, and c) outside resources available to the parents. Deliberation with the parents to help them reach their own decision is essential.  相似文献   
92.
93.
The current study was carried out to examine the clinical characteristics and survival-probability rates of 51 patients treated for oral (tongue) cancer and to correlate it with various tumor markers. The clinical data and survival probability rates were correlated with the immunohistological analysis of p27, Skp2, p53, Bcl-2, TUNEL (apoptotic rate) and c-erbB-2 markers. The 5-year survival-probability correlated with staging, grading and base of tongue location. An inverse relation between the expression of p27 and Skp2, p27 and grading, and a direct relation between Skp2 and grading were demonstrated. Concomitantly, significant correlations between low p27, high Skp2 and high TUNEL (apoptotic rate) expressions and between low p27 and high c-erbB-2 (Her2) expressions in the cancer lesions were demonstrated. The accumulated data may be employed in the future for a better understanding of the biology behind oral cancer and for developing better means of detection and treatment.  相似文献   
94.
BACKGROUND: Stem cell transplantation (SCT) may be associated with premature aging of the hematopoietic stem cells. Telomere length reflects the proliferative history of a cell. In most studies published so far on telomere dynamics after myeloablative allogeneic SCT, recipients had shorter telomeres than their respective donors, thus reflecting "accelerated aging" of hematopoietic cells. We evaluated telomere dynamics in patients who underwent transplantation with nonmyeloablative protocols, assuming that the decreased intensity of chemotherapy might prevent telomere attrition. METHODS: Telomere length was measured using FISH-FACS method. Telomeres of recipients were compared to their respective donors. Twenty-three consecutive patients after nonmyeloablative SCT were evaluated. A control group consisted of 10 donor-recipient pairs after conventional myeloablative transplantation. RESULTS: There was significant telomere shortening in both recipients of nonmyeloablative and myeloablative conditioning (0.487+/-0.65 kb, P=0.003; 0.361+/-0.50 kb, P=0.047 respectively). The extent of telomere shortening in the two groups was not different (P=0.64). There was no correlation between the degree of shortening and parameters such as time interval from transplant, age of donor or recipient, and the number of infused cells. CONCLUSIONS: This is the first study on telomere dynamics after nonmyeloablative conditioning SCT. The study demonstrates significant shortening of telomeres in recipients in spite of decreased intensity conditioning. Results of this study suggest that the main mechanism following transplantation is the proliferative stress imposed upon the stem cells and not direct damage by cytotoxic drugs. The different kinetics of restoration of hematopoiesis and the probable ongoing process of graft-versus-leukemia in the bone marrow do not prevent the attrition of telomeric ends of chromosomes.  相似文献   
95.

Background

The Rh blood system is one of the most polymorphic and immunogenic systems known to humans. The expression of Rh blood group antigen is complex. The Rh D antigen is the most important of the antigens that constitute the Rh antigen system. In most cases, D antigen can easily be detected. However, due to variability of expression, weak forms antigen are encountered. The reactivity of weak D with antisera is variable and presents as a problem in blood banking.

Methods

A retrospective analysis for a five-year period was done. Blood samples that were negative for Rh D by immediate spin tube method were tested for weak D antigen by additional lab tests.

Result

Of 34932 serial Rh grouping tests done in our Blood Bank, the incidence of weak D Rh antigen was 0.189%. All these were confirmed by the antiglobulin test.

Conclusion

These patients present as a problem for the blood banker and a curiosity to the clinician. Although uncommon, all health care workers should be aware of this entity to avoid anti D alloimmunisation.Key Words: Weak D, Rh Blood Group  相似文献   
96.
97.
98.
99.
The chemokine stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4 participate in the retention of normal hematopoietic stem cells within the bone marrow (BM) and their release into the circulation. Homing and engraftment of human stem cells in immunodeficient mice are dependent on cell surface CXCR4 expression and the production of BM SDF-1, which acts also as a survival factor for both human and murine stem cells. However, the role of SDF-1/CXCR4 interactions in the control of human acute myelogenous leukemia (AML) cell trafficking and disease progression is poorly understood. In this study, we report that although some AML cells do not express surface CXCR4, all AML cells tested express internal CXCR4 and SDF-1. Culture of AML cells with SDF-1 promoted their survival, whereas addition of neutralizing CXCR4 antibodies, SDF-1 antibodies, or AMD3100 significantly decreased it. Pretreatment of primary human AML cells with neutralizing CXCR4 antibodies blocked their homing into the BM and spleen of transplanted NOD/SCID/B2m(null) mice. Furthermore, weekly administrations of antihuman CXCR4 to mice previously engrafted with primary AML cells led to a dramatic decrease in the levels of human AML cells in the BM, blood, and spleen in a dose- and time-dependent manner. Interestingly, the same treatment did not affect significantly the levels of normal human progenitors engrafted into NOD/SCID mice. Taken together, our findings demonstrated the importance of the SDF-1/CXCR4 axis in the regulation of in vivo motility and development of human AML stem cells and identified CXCR4 neutralization as a potential treatment for AML.  相似文献   
100.
BACKGROUND AND AIMS: We have previously shown that naso-gastric tube (NGT)-fed patients harbor pathogenic flora in their oropharynx. The purpose of this study was to examine comparatively the biochemical, immunological and enzymatic components of the saliva of these patients with that of orally-fed counterparts. METHODS: The study group consisted of 19 elderly NGT-fed patients and 18 comparable patients on oral feeding. Unstimulated whole saliva was collected and analyzed according to accepted methods for sodium, potassium, chloride, uric acid, total protein, albumin, amylase, lysozyme, and immunoglobulins, IgM, IgG, IgA, as well as secretory IgA. RESULTS: None of the above tested salivary components significantly differed between the two groups. Only uric acid levels were significantly lower (50%, p < 0.05) in NGT-fed patients. CONCLUSIONS: Uric acid is the main antioxidant component of saliva and, as such, it may be related to pathogenic bacterial colonization of the oropharynx in NGT-fed patients, with the risk of aspiration pneumonia.  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-23

京公网安备 11010802026262号