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   63719篇
  免费   4162篇
  国内免费   125篇
耳鼻咽喉   613篇
儿科学   2554篇
妇产科学   1674篇
基础医学   8014篇
口腔科学   704篇
临床医学   9422篇
内科学   11044篇
皮肤病学   904篇
神经病学   5941篇
特种医学   1215篇
外科学   5833篇
综合类   680篇
一般理论   120篇
预防医学   8747篇
眼科学   891篇
药学   4220篇
中国医学   65篇
肿瘤学   5365篇
  2023年   397篇
  2022年   629篇
  2021年   1442篇
  2020年   936篇
  2019年   1408篇
  2018年   1617篇
  2017年   1261篇
  2016年   1337篇
  2015年   1539篇
  2014年   2132篇
  2013年   3217篇
  2012年   4660篇
  2011年   4922篇
  2010年   2721篇
  2009年   2381篇
  2008年   4284篇
  2007年   4427篇
  2006年   4268篇
  2005年   4373篇
  2004年   4173篇
  2003年   3861篇
  2002年   3597篇
  2001年   559篇
  2000年   414篇
  1999年   548篇
  1998年   723篇
  1997年   653篇
  1996年   521篇
  1995年   511篇
  1994年   460篇
  1993年   350篇
  1992年   277篇
  1991年   242篇
  1990年   237篇
  1989年   243篇
  1988年   222篇
  1987年   193篇
  1986年   182篇
  1985年   194篇
  1984年   205篇
  1983年   186篇
  1982年   224篇
  1981年   216篇
  1980年   166篇
  1979年   113篇
  1978年   140篇
  1977年   70篇
  1976年   80篇
  1975年   61篇
  1974年   85篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
During an exposure monitoring study, 78 saw maintenance tradesmen were randomly assigned to be interviewed about their exposures using one of two questionnaire formats: open-ended and partly prompted questions about five categories of materials; and detailed prompting about 75 agents. The more open-ended questionnaire elicited fewer exposure responses overall, but more responses about agents not included on the detailed questionnaire. Composite materials and trade name products were more frequently cited as exposures than individual metals or compounds. Validity of responses was ascertained using air measurements (individual metals) or observations of the employees (composite materials). Sums of sensitivities and specificities were very low (near 1.0) for most of the metals for both types of questionnaire. For composite materials, validity improved substantially. Sensitivities with the partly prompted format (0.44–0.85) were always lower than with detailed prompting (0.80–1.00). Specificities were usually, but not always, higher with partial prompting (0.66–0.92) than with detailed prompting (0.18–0.86). Selection of questionnaire format for an epidemiologic study would depend on the likely prevalence of exposure in controls and the effects of trade-offs in sensitivity and specificity.  相似文献   
132.
133.
134.
135.
The effect of weight loss with anorectic medications on sleep apnea, non-insulin-dependent diabetes, and steatohepatitis is illustrated in three cases from practice in a clinical nutrition setting. Prevention of obesity, a chronic disorder, is preferable, but when obesity becomes a major obstacle in the care of patients with respiratory, cardiovascular, and metabolic disorders and osteoarthritis, an intense course of weight reduction using anorectic medications under medical and dietetic guidance is essential for patients' survival and reduction of medical cost.  相似文献   
136.
We reviewed plain radiographs of 215 pediatric patients with surgically proven appendicitis to study the value of plain radiography for diagnosis.  相似文献   
137.
138.
OBJECTIVE: Our objective was to assess the effectiveness of skin care protocols, including a body wash and skin protectant, on skin breakdown in 2 nursing homes. DESIGN: This was a quasi-experimental pretest/posttest design study.Setting and subjects Adult residents (n = 136) of 2 skilled nursing homes consented to participate in this study. Seventy percent were women; the sample average age of 82 years. INSTRUMENTS: A researcher-designed data recording form documented resident demographics, incidence and type of skin breakdown or pressure ulcer, presence of urinary or fecal incontinence, and assessment of the effectiveness of body wash and skin protectant. METHODS: Baseline data on prevalence of pressure ulcers and skin protocol were collected weekly for a 3-month period followed by a week-long educational program by the researchers about skin care and the body wash and skin protectant. During the 3-month trial with the body wash and skin protectant incorporated into routine care, research assistants recorded resident data weekly and researchers again assessed prevalence and incidence of pressure ulcers and skin breakdown weekly. RESULTS: Incorporation of a body wash and skin protectant into a skin care prevention and early intervention protocol in 2 nursing homes documented a decrease in skin breakdowns from 68 pre-intervention to 40 postintervention; the decrease in agency B was statistically significant. There was a statistically significant decrease in stage I and II pressure ulcer incidence overall (pre-intervention = 19.9%, postintervention = 8.1%). Nurses evaluated the body wash and skin protectant as effective for 98% of the time used. CONCLUSION: Implementation of a protocol for skin care along with staff education, including the prophylactic use of a body wash and skin protectant, reduced the incidence of skin breakdown, including pressure ulcers and perineal dermatitis, in 2 long-term care facilities.  相似文献   
139.
Glucose is the obligate energetic fuel for the mammalian brain, and most studies of cerebral energy metabolism assume that the majority of cerebral glucose utilization fuels neuronal activity via oxidative metabolism, both in the basal and activated state. Glucose transporter (GLUT) proteins deliver glucose from the circulation to the brain: GLUT1 in the microvascular endothelial cells of the blood-brain barrier (BBB) and glia; GLUT3 in neurons. Lactate, the glycolytic product of glucose metabolism, is transported into and out of neural cells by the monocarboxylate transporters (MCT): MCT1 in the BBB and astrocytes and MCT2 in neurons. The proposal of the astrocyte-neuron lactate shuttle hypothesis suggested that astrocytes play the primary role in cerebral glucose utilization and generate lactate for neuronal energetics, especially during activation. Since the identification of the GLUTs and MCTs in brain, much has been learned about their transport properties, that is capacity and affinity for substrate, which must be considered in any model of cerebral glucose uptake and utilization. Using concentrations and kinetic parameters of GLUT1 and -3 in BBB endothelial cells, astrocytes, and neurons, along with the corresponding kinetic properties of the MCTs, we have successfully modeled brain glucose and lactate levels as well as lactate transients in response to neuronal stimulation. Simulations based on these parameters suggest that glucose readily diffuses through the basal lamina and interstitium to neurons, which are primarily responsible for glucose uptake, metabolism, and the generation of the lactate transients observed on neuronal activation.  相似文献   
140.
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