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   29660篇
  免费   2183篇
  国内免费   65篇
耳鼻咽喉   259篇
儿科学   1004篇
妇产科学   941篇
基础医学   3848篇
口腔科学   493篇
临床医学   3416篇
内科学   6193篇
皮肤病学   615篇
神经病学   2750篇
特种医学   847篇
外国民族医学   8篇
外科学   3594篇
综合类   309篇
一般理论   21篇
预防医学   3148篇
眼科学   668篇
药学   1777篇
中国医学   19篇
肿瘤学   1998篇
  2023年   270篇
  2022年   510篇
  2021年   956篇
  2020年   509篇
  2019年   918篇
  2018年   1035篇
  2017年   749篇
  2016年   774篇
  2015年   850篇
  2014年   1147篇
  2013年   1404篇
  2012年   2124篇
  2011年   2140篇
  2010年   1121篇
  2009年   955篇
  2008年   1584篇
  2007年   1546篇
  2006年   1476篇
  2005年   1424篇
  2004年   1302篇
  2003年   1085篇
  2002年   1027篇
  2001年   484篇
  2000年   440篇
  1999年   376篇
  1998年   233篇
  1997年   182篇
  1996年   162篇
  1995年   137篇
  1994年   140篇
  1993年   136篇
  1992年   360篇
  1991年   337篇
  1990年   291篇
  1989年   305篇
  1988年   276篇
  1987年   287篇
  1986年   246篇
  1985年   222篇
  1984年   176篇
  1983年   164篇
  1982年   102篇
  1981年   106篇
  1980年   113篇
  1979年   172篇
  1978年   140篇
  1977年   122篇
  1976年   105篇
  1974年   118篇
  1973年   118篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
The performance of therapeutic aspiration in the treatment of amebic liver abscess, advocated and practiced in many centers, is controversial. Previously, this practice has been evaluated in retrospective analyses. To test the potential benefit of therapeutic aspiration, the authors undertook a prospective randomized trial in 57 patients admitted for suspected amebic liver abscess during a 15-month period. Sixteen patients were excluded from the trial. The remaining 41 patients were randomly included in one of two study groups to receive amebicidal therapy alone or amebicidal therapy coupled with image-guided percutaneous therapeutic aspiration. All patients in the trial recovered. No statistically significant benefit was demonstrated in the aspiration group for the two objective parameters evaluated: length of hospitalization and duration of time to becoming afebrile. Subjective improvement in symptoms after aspiration was greater in the aspiration group at a marginally statistically significant level. These data do not support the adjunctive performance of percutaneous therapeutic aspiration in the treatment of uncomplicated amebic liver abscess. Amebicidals alone were equally efficacious in treating the group studied.  相似文献   
52.
Jackstone calculi are urinary tract stones that have a specific appearance resembling toy jacks. They are almost always composed of calcium oxalate dihydrate and may be found in the urinary bladder or rarely in the upper urinary tract. Their appearance on plain radiographs and computed tomography (CT) in human patients has been well described. They have also been imaged in several species of animals. However, our review of the English medical literature revealed no previous report in which a jackstone calculus had been identified on the sonographic examination of a human patient. We report a case in which a large jackstone calculus was incidentally detected during abdominal sonography in a 75-year-old man.  相似文献   
53.
The Commission on Macroeconomics and Health report (Sachs report of 2001) has been heralded as inspiring and groundbreaking and is being adopted as the blueprint for global health policymaking. This article argues that the report is deeply conservative and unoriginal. It encourages medico-technical solutions to public health problems; it ignores macroeconomic determinants and other root causes of both poor health and poverty; it reverses public health logic and history; it is based on a set of flawed assumptions; it reflects one particular economic perspective to the exclusion of all others; and it recommends greater amounts of charity while preserving the status quo of a deeply unjust and irrational international economic order. Wishful thinking and ideology are presented as established facts to legitimize globalization, and health is conceived primarily as an input to productivity rather than as a human right. The benefits that would result from simple, macroeconomic measures directed toward social justice and the meeting of basic needs are incomparably greater than those that would result from following CMH recommendations in terms of sustainable improvements in both health and economic well-being. The ultimate source of poor health status and miserable living conditions is the extreme concentration of power, nationally and internationally, in the hands of the few.  相似文献   
54.
Thrombospondin (TSP), a large glycoprotein present in platelets, and various normal and tumor tissues, has recently been shown to promote cell adhesion and platelet aggregation. Most importantly because TSP has been shown to promote metastasis of melanoma tumor cells to the lung in a murine model (1) and since thromboembolic events commonly occur in patients afflicted with metastatic tumors, we explored the role of TSP in human cancer by measuring TSP blood levels in patients with various malignant neoplasms. Blood TSP levels were measured by indirect enzyme-linked immunoadsorbent assay (ELISA) from 20 control subjects, 22 patients with gastrointestinal (GI) cancer, 18 patients with breast cancer, and 17 patients with lung cancer. Control subjects consisted both of healthy subjects and acutely ill patients with no malignancies. TSP levels of both healthy and acutely ill controls were found to range between 245-440 ng/ml with a mean of 365 ng/ml. In contrast, elevated levels of TSP greater than the mean value of 400 ng/ml for controls ranging between 590-3,650 ng/ml were found in 20/22 (91%) patients with GI malignancies, 13/18 (72%) patients with breast cancer, and 15/17 (88%) with lung cancer. Mean TSP levels of GI, breast, and lung cancer patients were 3, 2, and 3 fold greater than controls, respectively. Increased blood TSP levels in patients were not due to increased levels of platelets since both control and patient groups had platelet counts within the normal range. These results suggest that TSP may play a role in tumor cell metastasis in man and could serve as a blood marker for metastasis.  相似文献   
55.
56.
57.
Understanding of heart failure has developed through 3 paradigms involving organ, cell, and gene. The first views heart failure as an abnormality of organ (pump) function leading to salt and water retention and vasoconstriction. Therapy to correct these circulatory abnormalities is well accepted and effective. The second considers heart failure as a disordered cellular function, mainly impaired contraction and relaxation. Efforts to correct the biochemical and biophysical abnormalities responsible for these disorders of myocardial performance have, however, been less successful. Recent emphasis on efforts to improve prognosis as well as symptoms in patients with chronic heart failure demonstrates that it is a lethal disease with problems of survival similar to those in malignancies. The third paradigm of abnormal gene expression, which in the failing heart represents a cardiomyopathy of overload, appears to be a major cause of poor prognosis in these patients. Evidence that the angiotensin-converting enzyme inhibitors have important effects on cell growth, as well as on vascular tone, suggests that their ability to prolong survival in patients with heart failure may be due largely to the inhibition of detrimental effects of angiotensin II on cardiac gene expression. Thus, it seems likely that work focused on the third paradigm will uncover specific abnormalities of gene expression that are responsible for poor survival of patients with heart failure. By 2001, I predict that heart failure will be viewed as an abnormality of cell growth and this will lead to the development of therapies to retard, if not reverse, the clinical deterioration.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
58.
E Katz  C A Katz 《Dental economics》1992,82(1):45-6, 48-50
  相似文献   
59.
Investigations on the symptoms associated with the use of anticholinergic medications by elderly patients demonstrated that these medications are frequently associated with persistent adverse effects that may go unrecognized by both patients and physicians. An increase in autonomic symptoms was readily demonstrated in a group of elderly outpatients taking anticholinergics. Cognitive effects, however, were not apparent, possibly due to the heterogeneity of the populations studied. A parallel study did, however, demonstrate an association between anticholinergic medications and slowing of EEG background frequency. Findings on the relationship between EEG background frequency and cognitive measures suggest the possible value of the combined use of psychological and electrophysiological measures for identifying patients who require further evaluation of their medication regimen.  相似文献   
60.
Mantle cell lymphoma is non-Hodgkin's B-cell lymphoma characterized by the t(11;14)(q13;q32) translocation. Peripheral blood involvement of mantle cell lymphoma is usually associated with a poor prognosis and therefore, its identification is clinically important. In this study, we performed cyclin D1/IgH-probe fusion fluorescence in situ hybridization analysis on 223 peripheral blood samples: 185 from 125 mantle cell lymphoma patients, and 38 normal controls. The cutoff values for the test were established using normal controls. Flow cytometry on peripheral blood and corresponding bone marrow samples was used to evaluate this test. In all, 26% of the 185 peripheral blood samples and 27% of the 161 corresponding bone marrow samples were flow cytometry positive for mantle cell lymphoma. The mean numbers of single and- double-fusion signals and the mean number of CD5/CD19-positive cells, absolute blood lymphocyte count, and white blood cell count were significantly higher in peripheral blood and corresponding bone marrow samples with mantle cell lymphoma-positive flow cytometry. Double-fusion signals were more specific than single-fusion ones. Fluorescence in situ hybridization was far more likely to be positive for mantle cell lymphoma when the peripheral blood and the corresponding bone marrow samples had positive flow cytometry results or morphology (P<0.01). Our study indicates that cyclin D1/IgH-fusion fluorescence in situ hybridization analysis could be used to determine the presence and character of circulating mantle cell lymphoma cells in peripheral blood, thus enhancing our ability to evaluate leukemic mantle cell lymphoma and minimum residual disease.  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