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   2793篇
  免费   201篇
  国内免费   107篇
耳鼻咽喉   26篇
儿科学   93篇
妇产科学   16篇
基础医学   304篇
口腔科学   75篇
临床医学   337篇
内科学   719篇
皮肤病学   41篇
神经病学   177篇
特种医学   201篇
外科学   311篇
综合类   69篇
一般理论   2篇
预防医学   132篇
眼科学   71篇
药学   189篇
中国医学   7篇
肿瘤学   331篇
  2023年   16篇
  2022年   11篇
  2021年   49篇
  2020年   29篇
  2019年   52篇
  2018年   56篇
  2017年   50篇
  2016年   52篇
  2015年   78篇
  2014年   117篇
  2013年   135篇
  2012年   174篇
  2011年   162篇
  2010年   134篇
  2009年   111篇
  2008年   132篇
  2007年   198篇
  2006年   154篇
  2005年   150篇
  2004年   116篇
  2003年   113篇
  2002年   109篇
  2001年   91篇
  2000年   73篇
  1999年   69篇
  1998年   64篇
  1997年   57篇
  1996年   47篇
  1995年   50篇
  1994年   38篇
  1993年   50篇
  1992年   37篇
  1991年   19篇
  1990年   28篇
  1989年   32篇
  1988年   32篇
  1987年   31篇
  1986年   26篇
  1985年   25篇
  1984年   21篇
  1983年   9篇
  1982年   16篇
  1981年   10篇
  1980年   15篇
  1978年   6篇
  1977年   9篇
  1973年   5篇
  1971年   8篇
  1970年   5篇
  1967年   5篇
排序方式: 共有3101条查询结果,搜索用时 62 毫秒
231.
Background: An outbreak of food poisoning in a military establishment mess was investigated and remedial measures suggested.  相似文献   
232.
BACKGROUND AND PURPOSE: Physical therapists often use positioning to assist in the reexpansion of collapsed lung segments. An increase in lung sound intensity on auscultation is considered indicative of lung expansion. This study was designed to examine whether clinical interpretation of auscultatory findings is warranted. SUBJECTS: The subjects (5 male, 6 female) were young physical therapist students without pulmonary dysfunction (mean age=20.4 years, mean height=166.3 cm, mean weight=57.5 kg). Subjects with lung disease were excluded because pulmonary pathology is difficult to standardize. METHODS: Lung sounds electronically recorded over the posterior chest wall of subjects in sitting and side-lying positions were compared. Measures included peak intensity, frequency at maximum power, and median frequency. RESULTS: In the sitting position, inspiratory sounds recorded over the left posterior chest wall were louder than those recorded on the right side. In the side-lying positions, the sound intensity recorded from the dependent chest wall was louder than that recorded from the nondependent chest wall. In side-lying positions, the upper hemithorax is "nondependent," and the side in contact with the bed is "dependent." Sound intensities recorded over both posterior chest walls in the sitting position were louder than those recorded over the same lung area in the nondependent side-lying position. There was no difference in the sound intensity recorded between the sitting and dependent side-lying postures. CONCLUSION AND DISCUSSION: When comparative auscultation of the chest wall is used by physical therapists to assess the adequacy of pulmonary ventilation, patient posture and regional differences in breath sound intensity can influence clinical interpretation.  相似文献   
233.
高效液相色谱法测定寒痹停片中士的宁含量   总被引:6,自引:0,他引:6  
目的:建立用HPLC测定寒痹停片中士的含量的方法。方法:氰基柱;流动相-甲醇-水-三乙胺-乙酸(9800:155:15:30);紫外检测波长254nm。结果:在4~20ug/ml范围内,标准曲线回归方程为:Y=-2803+8967x(r=0.9997),RSD=1.65%?加样回收率的平均值为99.82%。结论:实验表明,这是一个适用于生产控制和产品质量检验的简单、快速、准确的方法。  相似文献   
234.
235.
There is increasing evidence that HOX homeobox genes play a role in leukemogenesis. Recent studies have demonstrated that enforced co-expression of HOXA9 and MEIS1 in murine marrow leads to rapid development of myeloid leukemia, and that these proteins exhibit cooperative DNA binding. However, it is unclear whether co-activation of HOXA9 and MEIS genes is a common occurrence in human leukemias. We surveyed expression of HOXA9 and MEIS1 in 24 leukemic cell lines and 80 patient samples, using RNase protection analyses and immunohistochemistry. We demonstrate that the expression of HOXA9 and MEIS1 in leukemia cells is uniquely myeloid, and that these genes are commonly co-expressed in myeloid cell lines and in samples of acute myelogenous leukemia (AML) of all subtypes except in promyelocytic leukemia. While HOXA9 is expressed in most cases of chronic myelogenous leukemia, MEIS1 is weakly expressed or not at all. Immunohistochemical staining of selected AML samples showed moderate to high levels of HOXA9 protein, primarily cytoplasmic, in leukemic myeloblasts, with weaker and primarily nuclear staining for MEIS1. These data support the concept that co-activation of HOXA9 and MEIS1 is a common event in AML, and may represent a common pathway of many different oncogenic mutations.  相似文献   
236.
Au WY  Ma SK  Kwong YL  Lie AK  Shek WH  Chow WC  Liang R 《Leukemia & lymphoma》1999,36(1-2):191-194
Granulocytic sarcoma (GS) is an increasingly common relapse feature of acute myeloid leukemia (AML), late in the disease course or post bone marrow transplantation (BMT). Any solid organ can be affected, and there have been a number of reports of GS in breast tissue in female patients. We present a unique case of GS in a male AML patient, presenting as painless gynecomastia immediately before BMT at advanced disease. Aberrant expression of CD56 was found in the relapsed GS tissue but not in the original AML clone. Twelve months after allogeneic BMT, leukemia relapsed again in the same breast, with normal marrow morphology and full donor chimerism. The lesion failed to respond to donor lymphocyte infusion, chemotherapy and radiotherapy, and disseminated to other subcutaneous tissues.  相似文献   
237.
238.
239.
OBJECTIVES: To review the treatment outcome of rhabdomyosarcoma in Hong Kong Chinese children. DESIGN: Retrospective review. SETTING: University teaching hospital, Hong Kong. PATIENTS: Consecutive cases of rhabdomyosarcoma diagnosed and treated by the Department of Paediatrics and Adolescent Medicine of Queen Mary Hospital between 1989 and 2005. Each patient was staged and treated according to the Intergroup Rhabdomyosarcoma Study guidelines. MAIN OUTCOME MEASURES: Overall and event-free survival rates, and toxicity data. RESULTS: Of 19 patients (8 males and 11 females), 14 (74%) were younger than 10 years old. The median age at diagnosis was 6 (range, 0.5-17) years. Primary sites of rhabdomyosarcoma included: the head and neck (n=8; 6 classified as cranial parameningeal), genitourinary (3), extremity (3), pelvis (3), and trunk (2). Thirteen (68%) had embryonal and six (32%) had alveolar histology. Two, 2, 9, and 6 were classified as belonging to Intergroup Rhabdomyosarcoma Study groups 1, 2, 3, and 4, respectively. Respective 5-year overall and event-free survival rates of the entire cohort were 49% (95% confidence interval, 26-73%) and 32% (10-55%), with a median follow-up of 3.4 (range, 0.2-16.7) years. In non-metastatic cases (Intergroup Rhabdomyosarcoma Study groups 1-3), the 5-year overall survival rate was 66% (95% confidence interval, 39-93%) and in metastatic cases (group 4) it was 17% (0-46%). The 5-year overall survival rate for patients aged less than 10 years was 60% (95% confidence interval, 33-87%) compared to 20% (0-55%) in those aged 10 years and over. Significant treatment-related toxicities including myelosuppression, infections, peripheral neuropathy, and second cancers were encountered. CONCLUSIONS: Treatment outcome of rhabdomyosarcoma in this cohort of Chinese children was less favourable than that reported in international studies. Whilst the main reason could have been related to the high proportion of metastatic cases, also non-metastatic cases faired worse. Improved outcomes may be achieved by advances in multidisciplinary (paediatric oncology, pathology, radiotherapy, and surgery) management and supportive care.  相似文献   
240.
ABSTRACT: BACKGROUND: During the 2009 H1N1 immunization campaign, electronic and hybrid (comprising both electronic and paper components) systems were employed to collect client-level vaccination data in clinics across Canada. Because different systems were used across the country, the 2009 immunization campaign offered an opportunity to study the usability of the various data collection methods. METHODS: A convenience sample of clinic staff working in public health agencies and hospitals in 9 provinces/territories across Canada completed a questionnaire in which they indicated their level of agreement with seven statements regarding the usability of the data collection system employed at their vaccination clinic. Questions included overall ease of use, effectiveness of the method utilized, efficiency at completing tasks, comfort using the method, ability to recover from mistakes, ease of learning the method and overall satisfaction with the method. A 5-point Likert-type scale was used to measure responses. RESULTS: Most respondents (96%) were employed in sites run by public health. Respondents included 186 nurses and 114 administrative staff, among whom 90% and 47%, respectively, used a paper-based method for data collection. Approximately half the respondents had a year or less of experience with immunization-related tasks during seasonal influenza campaigns. Over 90% of all frontline staff found their data collection method easy to use, perceived it to be effective in helping them complete their tasks, felt quick and comfortable using the method, and found the method easy to learn, regardless of whether a hybrid or electronic system was used. CONCLUSIONS: This study demonstrates that there may be a greater willingness of frontline immunization staff to adapt to new technologies than previously perceived by decision-makers. The public health community should recognize that usability may not be a barrier to implementing electronic methods for collecting individual-level immunization data.  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