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   20516篇
  免费   1304篇
  国内免费   38篇
耳鼻咽喉   128篇
儿科学   689篇
妇产科学   709篇
基础医学   2749篇
口腔科学   269篇
临床医学   3392篇
内科学   3871篇
皮肤病学   212篇
神经病学   2042篇
特种医学   308篇
外科学   1574篇
综合类   271篇
一般理论   31篇
预防医学   2819篇
眼科学   151篇
药学   1207篇
中国医学   13篇
肿瘤学   1423篇
  2023年   88篇
  2022年   143篇
  2021年   337篇
  2020年   214篇
  2019年   378篇
  2018年   397篇
  2017年   282篇
  2016年   358篇
  2015年   412篇
  2014年   607篇
  2013年   971篇
  2012年   1399篇
  2011年   1404篇
  2010年   773篇
  2009年   763篇
  2008年   1379篇
  2007年   1350篇
  2006年   1359篇
  2005年   1389篇
  2004年   1321篇
  2003年   1298篇
  2002年   1260篇
  2001年   182篇
  2000年   166篇
  1999年   205篇
  1998年   255篇
  1997年   222篇
  1996年   182篇
  1995年   194篇
  1994年   171篇
  1993年   170篇
  1992年   161篇
  1991年   143篇
  1990年   133篇
  1989年   127篇
  1988年   127篇
  1987年   131篇
  1986年   106篇
  1985年   105篇
  1984年   143篇
  1983年   101篇
  1982年   129篇
  1981年   113篇
  1980年   111篇
  1979年   77篇
  1978年   73篇
  1977年   53篇
  1976年   53篇
  1975年   47篇
  1974年   50篇
排序方式: 共有10000条查询结果,搜索用时 906 毫秒
51.
PURPOSE: Evaluate the effectiveness of body mass index (BMI) tables placed in exam rooms as an intervention to encourage providers to calculate and record BMI scores in patients' medical records. DESIGN: In a prospective cohort design, medical record data for 276 adult patients at a federally funded community health center in New England were examined from August 2000 to August 2002 following the intervention. METHODS: Prominent, multicolored, laminated BMI tables were posted in the exam rooms of one of the study site's three primary health care teams. Medical record data collected included documentation of BMI calculation in medical records, documentation of an obesity diagnosis, and inclusion of heights and current weights. Frequency distributions were calculated; chi-square tests were used to identify associations. FINDINGS: In contrast to the comparison teams, patients on the intervention team were more likely to have BMI recorded in the medical record. A statistically significant increase in the diagnosis of obesity was observed throughout the health center after the intervention. CONCLUSIONS: Posting BMI tables in exam rooms contributed to increased BMI documentation in patients' medical records.  相似文献   
52.
Brain magnetic resonance images (MRI) of 104 healthy childrenand adolescents, aged 4–18, showed significant effectsof age and gender on brain morphometry. Males had larger cerebral(9%) and cerebellar (8%) volumes (P < 0.0001 and P = 0.008.respectively), which remained significant even after correctionfor height and weight After adjusting for cerebral size, theputamen and globus pallidus remained larger in males, whilerelative caudate size was larger in females. Neither cerebralnor cerebellar volume changed significantly across this agerange. Lateral ventricular volume increased significantly inmales (trend for females), with males showing an increase inslope after age 11. In males only, caudate and putamen decreasedwith age (P = 0.007 and 0.05, respectively). The left lateralventricles and putamen were significantly greater than the rightP = 0.01 and 0.0001, respectively). In contrast, the cerebralhemispheres and caudate showed a highly consistent right greater-than-leftasymmetry (P < 0.0001 for both). All volumes demonstrateda high degree of variability. These findings highlight gender-specificmaturational changes of the developing brain and the need forlarge gender-matched samples in pediatric neuropsychiatric studies.  相似文献   
53.
Critical care nurses, ethical decision-making and stress   总被引:2,自引:0,他引:2  
Considerable attention has focused on describing ethical issues that critical care nurses face in their practice; however, less attention has been directed at describing the process of ethical decision-making. Systematic research linking aspects of ethical-decision making and stress is lacking. This cross-sectional study examines the relationship between selected aspects of ethical decision-making, stress and selected nurse characteristics. Sixty-one critical care nurses completed the Nurse's Ethical Decision Making—ICU Questionnaire and the Health Professions Stress Inventory. Findings revealed that nurses who selected the patient advocacy model had significantly higher nurse autonomy scores, that perceived anxiety had a negative association with nurse autonomy, and that workplace restrictions and stress were related.  相似文献   
54.
55.
INTRODUCTION: Farming is a dangerous occupation and results in injuries not only to farm workers, but also to families living on farms. Children raised on a farm are at particular risk because the farm is a place where they live, play, and work. Farming is the main Amish occupation, and because Amish farming techniques differ from those used on other us farms, it is important that health care providers recognize the causes of injuries that may occur on Amish farms. However, little is documented about farm-related injuries in Amish children, so we decided to document the incidence and nature of these injuries in Pennsylvania. METHODS: This study was done by reviewing the die botschaft, a weekly newspaper written by the Amish. All references to farm-related injuries among children in Pennsylvania were recorded. RESULTS: During a 5-month period, a total of 89 injuries, including 5 fatalities, were found: male children sustained 64 injuries, and female children sustained 25 injuries. Falls were the most commonly reported mechanism of injury, followed by incidents involving livestock. Both types of events most often resulted in an orthopedic injury. DISCUSSION: Injury to children in the Amish community is a significant problem that needs to be addressed and evaluated by the Amish themselves and in coordination with other health care providers, including emergency nurses. With the information obtained in this study, injury prevention strategies tailored to the Amish way of farming could be developed and implemented.  相似文献   
56.
57.
58.
Job ending among youth and adults with severe mental illness   总被引:1,自引:0,他引:1  
This study examined job leaving over a 36-month period among 326 persons (74 youth and 252 adults) with severe mental illness who were participating in an urban vocational rehabilitation program. Data from 627 job endings indicated that younger clients displayed job-ending patterns that were different in some aspects from such patterns for nondisabled youth (such as displaying a lower average job tenure) yet similar to job-ending patterns for nonhandicapped youth in other ways (such as displaying a high frequency of job changing). Youth and their adult counterparts with mental illness displayed similar tenure on agency-sponsored placements but significantly different tenure on independent jobs. While adults held their independent jobs for an average of seven months, youth averaged only three months at competitive employment. Youth also were significantly more likely than adults to be fired from both placements and independent jobs. These findings and others are discussed in terms of their implications for development of public policy and service delivery models for providing on-going job support to youth and adults with severe psychiatric disabilities.  相似文献   
59.
OBJECTIVE: Normal elderly men are reported to have decreased testicular function despite elevated gonadotrophin levels. We wished therefore to determine if changes in testicular function occur over the age range 19-60 years. DESIGN: Single fasting blood samples were obtained between 0800 and 0900 h. PATIENTS: Working men in a large industrial company between the ages of 19 and 60 years participated in the study. MEASUREMENTS: FSH, serum immunoreactive inhibin and total testosterone were measured, the latter two as measurements of Sertoli and Leydig cell function respectively. RESULTS: The mean baseline serum immunoreactive inhibin level was significantly lower in men from the older age groups, 31-40 years (479 U/l), 41-50 years (439 U/l) and 51-60 years (415 U/l) than in men from the youngest age group, 21-30 years (613 U/l) while serum FSH was higher in men from the older age groups, 41-50 years (3.7 IU/l) and 51-60 years (6.1 IU/l) than in men from the youngest age group, 21-30 years (2.6 IU/l). There appears to be a change in both FSH and inhibin production, consistent with a primary decline in testicular function. There was no significant difference in testosterone levels between the older age group, age 51-60 years and the younger age group, age 21-30 years. However, testosterone levels were significantly lower in the 41-50 year age group, when compared with the 21-30 year, this significance levelling out at about age 45 years. CONCLUSION: The data are consistent with the hypothesis that immunoreactive inhibin reflects inhibin bioactivity, and that inhibin plays a role in the feedback control of FSH secretion in men.  相似文献   
60.
Background: Angiogenesis is essential for tumor growth and metastasis. Vascular endothelial growth factor (VEGF) is the most potent angiogenic factor identified to date. TGFβ-1 acts as an indirect angiogenic agent. Methods: VEGF and TGFβ-1 were measured in the serum of breast cancer patients and agematched controls and in tumor tissue of cancer patients by ELISA. VEGF protein and mRNA expression by breast tumor cell lines were examined, and the effect of TGFβ-1 on VEGF production in these cells was assessed. Results: VEGF levels were significantly higher (P=.03) in the serum of patients with breast cancer compared to age-matched controls. A positive correlation was found between serum (r=0.539) and tumor tissue (r=0.688) levels of VEGF and TGFβ-1. Metastatic MDA-MB-231 breast cancer cells produce more VEGF than do the primary BT474 cells. TGFβ-1 significantly (P<.05) increased production of VEGF. Conclusions: Breast cancer cells constitutively produce VEGF protein and mRNA. There is a relationship between VEGF and TGFβ-1 levels in breast cancer patients, and TGFβ-1 regulates VEGF expression by breast cancer cells. Presented at the 50th Annual Cancer Symposium of the Society of Surgical Oncology, Chicago, Illinois, March 20–23, 1997.  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