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   1142篇
  免费   74篇
  国内免费   11篇
耳鼻咽喉   2篇
儿科学   87篇
妇产科学   36篇
基础医学   113篇
口腔科学   25篇
临床医学   142篇
内科学   229篇
皮肤病学   20篇
神经病学   24篇
特种医学   308篇
外科学   66篇
综合类   19篇
预防医学   49篇
眼科学   16篇
药学   30篇
中国医学   1篇
肿瘤学   60篇
  2021年   8篇
  2020年   4篇
  2019年   5篇
  2018年   14篇
  2017年   3篇
  2016年   8篇
  2015年   15篇
  2014年   19篇
  2013年   23篇
  2012年   12篇
  2011年   14篇
  2010年   29篇
  2009年   26篇
  2008年   16篇
  2007年   33篇
  2006年   22篇
  2005年   32篇
  2004年   29篇
  2003年   14篇
  2002年   15篇
  2001年   13篇
  2000年   12篇
  1999年   26篇
  1998年   97篇
  1997年   69篇
  1996年   76篇
  1995年   52篇
  1994年   54篇
  1993年   61篇
  1992年   14篇
  1991年   8篇
  1990年   14篇
  1989年   44篇
  1988年   25篇
  1987年   43篇
  1986年   27篇
  1985年   30篇
  1984年   27篇
  1983年   21篇
  1982年   23篇
  1981年   23篇
  1980年   28篇
  1979年   12篇
  1978年   18篇
  1977年   18篇
  1976年   21篇
  1975年   13篇
  1974年   4篇
  1970年   2篇
  1969年   2篇
排序方式: 共有1227条查询结果,搜索用时 15 毫秒
111.
112.
OBJECTIVE: We investigated whether the rate of viral rebound decreases with increasing duration of viral suppression and, if so, whether rebound rates in patients previously failing antiretroviral regimens ultimately decline to levels as low as those seen in patients who have never experienced virological failure. METHODS: All patients from the UK CHIC Study (n = 21 256) who achieved a viral load (VL) of < or = 50 copies/ml while receiving HAART were followed until viral rebound (two consecutive VL > 400 copies/ml). Patients could re-enter the analysis if they experienced a subsequent VL < or = 50 copies/ml. Rebound rates were calculated according to the number of regimens previously failed and duration of viral suppression. RESULTS: Of 12 648 patients on HAART 10 237 (80.9%) achieved a VL < or = 50 copies/ml. During 26 494 person-years (PY) of follow-up, 1853 (18.1%) patients experienced at least one viral rebound 'event', with 2460 events in total [rebound rate, 9.3 (range, 8.9-9.7)/100 PY). Within the first year of viral suppression, the rate of viral rebound was 8.3 (7.5-9.1)/100 PY in patients who had not previously failed treatment, increasing to 32.7 (27.6-37.8)/100 PY in patients who had failed more than four regimens. Irrespective of previous treatment failure, rebound rates in those who remained suppressed for > 4 years were similar to those in patients who had at no time experienced treatment failure. CONCLUSION: After around 4 years of viral suppression rebound rates in individuals with multiple prior treatment failures approach those of individuals with no prior treatment failure.  相似文献   
113.
We measured red blood cell iron incorporation (RBC-inc) in 13 human milk-fed premature infants (birthweight 1037 +/- 289 g, gestational age 27 +/- 2 wk, weight at start of study 1571 +/- 426 g) who were receiving full tube-feedings of human milk fortified with a commercial human milk fortifier (FortHM). The relative RBC-inc of supplemental iron (2 mg/kg/d of ferrous sulfate) was assessed using 57Fe sulfate mixed directly into a 24-h volume of FortHM, and 54Fe sulfate given as a bolus between two FortHM feedings the next day. RBC-inc was similar between the two methods of supplemental iron administration (4.7 +/- 2.5% vs 4.6 +/- 1.5%, respectively). Although these values are lower than RBC-inc expected from iron native to human milk, the relatively large amount of iron in the supplements contributed most of the iron incorporated into RBC by the infants. There was a significant positive correlation between the reticulocyte count and RBC-inc. As the high nutrient (especially calcium) content of the FortHM did not interfere with iron utilization, adding iron directly to FortHM, or incorporating it into commercial fortifiers, may be a practical method to provide iron to premature infants.  相似文献   
114.
Objectives: To assess the influence of clinical status on the association between total plasma bilirubin and unbound bilirubin on death or adverse neurodevelopmental outcomes at 18–22 months corrected age in extremely low birth weight infants. Method: Total plasma bilirubin and unbound bilirubin were measured in 1101 extremely low birth weight infants at 5 ± 1 days of age. Clinical criteria were used to classify infants as clinically stable or unstable. Survivors were examined at 18–22 months corrected age by certified examiners. Outcome variables were death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death prior to follow‐up. For all outcomes, the interaction between bilirubin variables and clinical status was assessed in logistic regression analyses adjusted for multiple risk factors. Results: Regardless of clinical status, an increasing level of unbound bilirubin was associated with higher rates of death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss and death before follow‐up. Total plasma bilirubin values were directly associated with death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death before follow‐up in unstable infants, but not in stable infants. An inverse association between total plasma bilirubin and death or cerebral palsy was found in stable infants. Conclusions: In extremely low birth weight infants, clinical status at 5 days of age affects the association between total plasma bilirubin and death or adverse neurodevelopmental outcomes at 18–22 months of corrected age. An increasing level of UB is associated a higher risk of death or adverse neurodevelopmental outcomes regardless of clinical status. Increasing levels of total plasma bilirubin are directly associated with increasing risk of death or adverse neurodevelopmental outcomes in unstable, but not in stable infants.  相似文献   
115.
Chloramphenicol is a topical treatment that is used widely, especially in wounds around the eyes. In our practice there have been a number of cases of delayed hypersensitivity to chloramphenicol that has been mismanaged initially as an infective cellulitis. We hope to share some of our experience of this uncommon reaction to highlight the delayed reaction that can occur with topical application of this drug.  相似文献   
116.
117.
BACKGROUND: Atopic dermatitis (AD) can be traumatizing to family life. Little is known about the relationship between quality of life in AD and disease severity. OBJECTIVE: To document family quality of life and relate this to severity of AD in children, for a 6-month period from a given point in time. STUDY DESIGN: These data are part of a longitudinal study conducted in two parts of the UK to investigate risk factors for AD severity and its impact on quality of life. SUBJECTS: and methods Thetargetedpopulation comprised children with AD aged 5-10 years in a primary-care setting. The general practitioners identified potential subjects and the UK diagnostic criteria for AD were used to verify the diagnosis. Both the children and their parents were interviewed. Eczema severity was assessed using a modified form of the SCORAD (SCORe Atopic Dermatitis) Index (SCORAD-D) from which parents' score of itching and sleep loss were excluded. The quality of family life was quantified by the Dermatitis Family Impact (DFI) questionnaire. These two parameters were evaluated on two occasions 6 months apart. ANALYSIS: Multiple regression analysis was used to investigate the relationship between the quality of family life and the severity of the AD in the children, at a specific point in time and over the following 6-month period. RESULTS: Of the 116 children attending the first visit, mean age 8 years, 106 attended the second visit (91%) and were included in the analysis. Quality of family life was shown to be significantly affected in 48 (45%) cases at the first visit and 38 (36%) cases at the second visit. The initial means of the DFI and SCORAD-D were 2.4 and 8.2, respectively. Six months later the mean final DFI and SCORAD-D were 1.9 and 7.7, respectively. Using multiple regression on the first and second visits, each unit increase in SCORAD-D was associated with 0.21 [95% confidence interval (CI) 0.06-0.37 P = 0.008] and 0.37 (95% CI 0.15-0.59, P = 0.001) units increase in quality of family life, respectively. This relationship remained significant even after adjustment for potential confounders (black skin, social class, sex, child's age, family size and location) each unit increase in SCORAD-D led to a 0.25 unit (95% CI 0.11-0.4, P = 0.001) and 0.23 unit (95% CI 0.05-0.42, P = 0.014) increase in DFI on the first and second visits, respectively. Changes in the DFI scores were significantly related to changes in the SCORAD-D scores (regression coefficient; 0.17 (95% CI 0.06-0.29, P = 0.002). CONCLUSIONS: We show that quality of family life is related to the severity of AD in children. This confirms the importance of parental assessment of the impact of the disease in the management of AD, because the disease affects the entire family. Also, these results show the response of DFI to change predictably with disease severity. This may imply that the DFI questionnaire could be used as an extra measure of outcome in everyday clinical practice as well as in research studies.  相似文献   
118.
119.
120.
In order to test the hypothesis that integrin and uteroglobin (UG) expression in cultured endometrial cells are affected by hormone treatment, Ishikawa-CH endometrial cancer cells were cultured and exposed to oestradiol or oestradiol and progesterone regimens and assayed using immunohistochemistry. We evaluated the intensity of immunohistochemical staining for the integrin monomers alpha(v) and beta1, the dimers alpha(v)beta3 and alpha(v)beta6, and for the secretory protein uteroglobin under various experimental conditions. Cells grown in control media stained positively for the integrin monomers alpha(v) and beta1, the dimer alpha(v)beta3, and for UG. Oestradiol and sequential oestradiol/progesterone reversibly suppressed staining for the dimer alpha(v)beta3. Hormone treatment had no effect on the staining of the beta1 and alpha(v) monomers or UG. The alpha(v)beta6 dimer antibody did not stain under any experimental treatment conditions. These data indicate that expression of the integrin complex alpha(v)beta3 is reversibly suppressed by oestradiol in Ishikawa cells and that these cells may be a good model for studying hormone-driven molecular changes in endometrium.   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