全文获取类型
收费全文 | 648篇 |
免费 | 24篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 22篇 |
妇产科学 | 1篇 |
基础医学 | 75篇 |
口腔科学 | 14篇 |
临床医学 | 72篇 |
内科学 | 194篇 |
皮肤病学 | 5篇 |
神经病学 | 12篇 |
特种医学 | 205篇 |
外科学 | 28篇 |
综合类 | 8篇 |
预防医学 | 25篇 |
眼科学 | 4篇 |
药学 | 19篇 |
中国医学 | 1篇 |
肿瘤学 | 25篇 |
出版年
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2016年 | 5篇 |
2015年 | 14篇 |
2014年 | 10篇 |
2013年 | 13篇 |
2012年 | 3篇 |
2011年 | 10篇 |
2010年 | 14篇 |
2009年 | 18篇 |
2008年 | 8篇 |
2007年 | 34篇 |
2006年 | 12篇 |
2005年 | 15篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 10篇 |
1998年 | 35篇 |
1997年 | 34篇 |
1996年 | 37篇 |
1995年 | 31篇 |
1994年 | 47篇 |
1993年 | 24篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 35篇 |
1988年 | 34篇 |
1987年 | 34篇 |
1986年 | 22篇 |
1985年 | 19篇 |
1984年 | 17篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1942年 | 2篇 |
1941年 | 3篇 |
1939年 | 4篇 |
1938年 | 5篇 |
1937年 | 9篇 |
1936年 | 6篇 |
1931年 | 2篇 |
排序方式: 共有714条查询结果,搜索用时 15 毫秒
31.
DL DSouza SB Heinze RJ Dowling 《Journal of Medical Imaging and Radiation Oncology》2006,50(3):246-248
Lung cancer is not commonly known to metastasise to the perirenal space, with only five such cases previously published. We present an unusual case of perirenal lung metastases manifesting as diffuse perinephric stranding which to our knowledge has not been described before. 相似文献
32.
Brandon DL Marshall Thomas Kerr Chris Livingstone Kathy Li Julio SG Montaner Evan Wood 《Harm reduction journal》2008,5(1):35
Aboriginal people experience a disproportionate burden of HIV infection among the adult population in Canada; however, less
is known regarding the prevalence and characteristics of HIV positivity among drug-using and street-involved Aboriginal youth.
We examined HIV seroprevalence and risk factors among a cohort of 529 street-involved youth in Vancouver, Canada. At baseline,
15 (2.8%) were HIV positive, of whom 7 (46.7%) were Aboriginal. Aboriginal ethnicity was a significant correlate of HIV infection
(odds ratio = 2.87, 95%CI: 1.02 – 8.09). Of the HIV positive participants, 2 (28.6%) Aboriginals and 6 (75.0%) non-Aboriginals
reported injection drug use; furthermore, hepatitis C co-infection was significantly less common among Aboriginal participants
(p = 0.041). These findings suggest that factors other than injection drug use may promote HIV transmission among street-involved
Aboriginal youth, and provide further evidence that culturally appropriate and evidence-based interventions for HIV prevention
among Aboriginal young people are urgently required. 相似文献
33.
Age-related postural deficits elicit compensatory mechanisms such as ankle dorsiflexion in the elderly. To gain further insight into this problem, the ability to match an ankle angle during quiet stance was studied in 12 elderly and 12 young subjects. Following an initial single limb angular perturbation presented in the ±4° range, a subject had to return a tilt platform to level, as determined by the nonperturbed limb. Elderly subjects exhibited significant positive (0.9°) over-shoot of the level position, in contrast to young subjects who matched ankle angle with a mean error of −0.1°. The elderly group also exhibited an increase in positioning error for angular displacements in the range between −1 and +1°. The results document age-related postural changes in ankle positioning which might affect postural stability in older adults. 相似文献
34.
Differential CT diagnosis of extruded nucleus pulposus 总被引:1,自引:0,他引:1
35.
Identification of candidate antigens for serologic detection of Helicobacter pylori-infected patients with gastric carcinoma 总被引:9,自引:0,他引:9
Krah A Miehlke S Pleissner KP Zimny-Arndt U Kirsch C Lehn N Meyer TF Jungblut PR Aebischer T 《International journal of cancer. Journal international du cancer》2004,108(3):456-463
Helicobacter pylori colonizes the stomach of almost half the world population and is a causative agent of gastric carcinomas and duodenal ulcers. Only a small fraction of infected people will develop these severe illnesses and a predictive test to identify people at high risk would greatly benefit disease management. Our study aimed to identify conserved bacterial antigens that may be useful for the development of such a diagnostic test. High-resolution immunoproteomics by 2-dimensional electrophoresis of H. pylori 26695 proteins was carried out with sera from infected patients with either duodenal ulcer (n=30) or gastric carcinoma (n=30), 2 clinically divergent conditions. According to their antigen recognition patterns clear groups of patients were identified. Although this classification did not correspond to the clinical status, it may be correlated to other bacterial or host factors that influence the outcome of infection. In general antigen recognition patterns were found to be highly variable, however by utilizing powerful image analysis and statistical tests the recognition of 14 antigenic protein species was found to differ significantly (p<0.01) between both diseases. Particular protein species of GroEL, HyuA, GroES and AtpA appear to be useful surrogate markers for gastric carcinoma detection and consequently should be considered for further prospective studies to assess their predictive value. For one protein species of AtpA, evidence was found that different post-translational modifications may confer different immunogenicities. 相似文献
36.
Clark HF Burke CJ Volkin DB Offit P Ward RL Bresee JS Dennehy P Gooch WM Malacaman E Matson D Walter E Watson B Krah DL Dallas MJ Schödel F Kaplan kM Heaton P 《The Pediatric infectious disease journal》2003,22(10):914-920
BACKGROUND: A refrigerator-stable rotavirus (RV) vaccine that withstands gastric acid is anticipated to permit more widespread use of RV vaccine. OBJECTIVE: We investigated for the first time in infants an oral, liquid formulation of G1 and G2 human bovine reassortant rotavirus vaccine (HRRV) with a new stabilizer/buffer (S/B) containing sucrose, sodium phosphate and sodium citrate. METHODS: During 1997 through 1998, 731 healthy infants approximately 2 to 4 months of age were enrolled at 19 US sites to receive 3 HRRV or placebo doses approximately 6 to 8 weeks apart in a partially double blinded study. Infants were randomized to: (1) HRRV with no S/B but with prefeeding; (2) HRRV plus 1 of 3 different concentrations/volumes of S/B; or (3) placebo. RESULTS: No serious vaccine-related adverse experiences or intussusception cases were reported. No statistically significant differences were observed between vaccine and placebo recipients for fever (> or =38.1 degrees C) 0 to 7 days after any dose, irritability, vomiting or diarrhea incidence 0 to 42 days after any dose. Vaccine virus shedding among vaccine recipients was uncommon. Among S/B vaccine groups, proportions of infants with a > or =3-fold titer rise from baseline to Postdose 3 for G1 serum-neutralizing antibody (SNA), G2 SNA, WC3 SNA, serum anti-RV IgA, serum anti-RV IgG and stool anti-RV IgA were generally similar to those of the prefed non-S/B group. CONCLUSIONS: HRRV with a new S/B was generally well-tolerated; immunogenicity was generally similar to the prefed non-S/B group. No intussusception cases were reported, but the small sample size precluded a definitive conclusion. A large international clinical study is under way to address safety and efficacy of an S/B formulation of a pentavalent version of HRRV. 相似文献
37.
38.
Simultaneous sonography and quantitative serum human chorionic gonadotropin (HCG) levels from 126 women with threatened abortion were compared. Of 56 women with normal outcome, 39 (70%) had a gestation sac greater than or equal to 5 mm in mean sac diameter, and in each case the HCG level was 1,800 milli-international units (mIU/ml) or greater. The serum HCG levels strongly correlated with the gestation sac sizes to a mean sac diameter of 25 mm. Of 70 abnormal pregnancies, 31 demonstrated a gestation sac. Of these, 20 women (65%) had disproportionately low HCG levels relative to sac size, including 12 in whom the HCG level was less than 1,800 mIU/ml. One woman with an early molar pregnancy had a disproportionately elevated HCG level. Correlation of sonograms with a simultaneous measurement of serum HCG level is a useful method for evaluating threatened spontaneous abortion. A disproportionately low HCG level relative to gestation sac size is evidence for an abnormal pregnancy. 相似文献
39.
40.
W Oh DK Stevenson JE Tyson BH Morris CE Ahlfors G Jesse Bender RJ Wong R Perritt BR Vohr KP Van Meurs HJ Vreman A Das DL Phelps T Michael O’Shea RD Higgins 《Acta paediatrica (Oslo, Norway : 1992)》2010,99(5):673-678
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