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   1293篇
  免费   93篇
  国内免费   8篇
耳鼻咽喉   5篇
儿科学   36篇
妇产科学   48篇
基础医学   140篇
口腔科学   45篇
临床医学   126篇
内科学   288篇
皮肤病学   43篇
神经病学   85篇
特种医学   30篇
外国民族医学   2篇
外科学   120篇
综合类   45篇
一般理论   2篇
预防医学   103篇
眼科学   19篇
药学   186篇
中国医学   4篇
肿瘤学   67篇
  2023年   19篇
  2022年   44篇
  2021年   66篇
  2020年   38篇
  2019年   84篇
  2018年   86篇
  2017年   65篇
  2016年   32篇
  2015年   39篇
  2014年   62篇
  2013年   82篇
  2012年   131篇
  2011年   102篇
  2010年   55篇
  2009年   47篇
  2008年   60篇
  2007年   56篇
  2006年   52篇
  2005年   39篇
  2004年   51篇
  2003年   39篇
  2002年   27篇
  2001年   9篇
  2000年   4篇
  1999年   4篇
  1998年   4篇
  1997年   5篇
  1996年   5篇
  1995年   3篇
  1994年   4篇
  1993年   6篇
  1992年   3篇
  1991年   2篇
  1990年   5篇
  1989年   2篇
  1988年   6篇
  1986年   2篇
  1985年   2篇
  1984年   7篇
  1983年   4篇
  1982年   10篇
  1981年   4篇
  1980年   2篇
  1979年   4篇
  1978年   2篇
  1972年   2篇
  1971年   2篇
  1968年   2篇
  1967年   3篇
  1938年   1篇
排序方式: 共有1394条查询结果,搜索用时 15 毫秒
81.
82.
OBJECTIVE: To report parental decisions regarding pregnancy termination following the prenatal diagnosis of a sex chromosome abnormality (SCA) in the fetus. METHODS: Retrospective collection of data from records of 61 families receiving genetic counseling after prenatal diagnosis of a sex chromosome abnormality in the fetus in the Division of Medical Genetics, University Hospital of Geneva during the time period 1980-2001. RESULTS: Among 61 couples with a prenatal diagnosis of a sex chromosome abnormality (SCA), 44 couples (72.1%) decided to terminate pregnancy. Pregnancy termination rates were 100, 73.9, 70, 50 and 42.9% for Turner syndrome, Klinefelter syndrome, 47,XXX females, 47,XYY males, and mosaic cases, respectively. In all 11 cases with a fetal abnormality seen on ultrasound, pregnancy was terminated. Termination rates were higher among couples with a higher mean number of previous children. Maternal age and year of test did not influence parental decisions. CONCLUSIONS: Parental decision to terminate a pregnancy for a fetus with a SCA varied by type of sex chromosome abnormality, by presence of fetal ultrasound anomalies, and by the mean number of previous children.  相似文献   
83.
Rapidly progressive glomerulonephritis (RPGN) is a rare occurrence in IgA nephropathy (IgAN) in renal transplant patients on immunosuppressive therapy. RPGN post ischemia-reperfusion has not been previously reported. We report a 62 year old male patient on azathioprine therapy, 9 years after left cadaveric renal transplantation due to end stage renal disease of unknown etiology, who presented with progressive deterioration in renal function and hematuria. Renal biopsy was consistent with IgAN. Duplex and CT scan demonstrated a decreased renal graft perfusion, due to severe atherosclerosis and stenosis of iliac arteries. The patient underwent left axilo-femoral bypass graft surgery with improvement in kidney graft perfusion and function. However, few weeks later, patient presented with pulmonary edema and advanced renal failure and he was initiated on hemodialysis. Repeated renal biopsy demonstrated crescentic GN. To the best of our knowledge, this is the first report of RPGN following reversal of ischemia and reperfusion. There was no evidence for atherembolic disease which is not uncommon after vascular surgery and it has been reported to be rarely associated to crescentic GN. Theoretical explanations for exacerbation of IgAN to crescentic GN, following successful reperfusion, could be enhancement of capillary damage, inflammation and oxidative stress. Putative mechanisms for these phenomena may be interaction of reperfusion-induced hyperfiltration, high intraglomerular capillary pressure, oxidative stress, increased polymorphonucler cells infiltration and inflammation; the presence of IgA immune deposits and azathioprine metabolites, both can also be associated to enhancement of oxidative stress.  相似文献   
84.
85.
86.
BACKGROUND: The annual Hajj pilgrimage to Mecca, Saudi Arabia brings over two million people to a small confined area. Respiratory tract infection is the most common disease transmitted during this period. For most of the etiologic agents of upper respiratory tract infections, no vaccine or prophylaxis is available, except for influenza. Yearly influenza vaccination of high-risk groups is recommended, but no special recommendations are available for those performing the Hajj or other similar large congregational activities. Viral surveillance studies are being carried out through more than 100 centers around the world to identify newly emerging viruses. Saudi Arabia is not one of those centers and no routine surveillance takes place. METHODS: Five hundred Hajj pilgrims presenting with upper respiratory tract symptoms from different parts of the world were screened by way of a throat swab for viral culture, including influenza A and B, parainfluenza, respiratory syncytial virus (RSV), adenovirus, herpes simplex virus (HSV), and enteroviruses. Information was collected on age, sex, nationality, smoking habits and upper respiratory tract symptoms. Vaccination status for influenza and meningococcus was obtained by self-declaration, since most pilgrims did not have their vaccination cards with them. Only those with symptoms including at least fever, reported by the patient to be >38.3 degrees C, and/or sore throat were included. Pilgrims with any other symptoms, especially myalgia and fatigue alone, were excluded, since many of the physical chores during the pilgrimage may contribute to such symptoms. RESULTS: Fifty-four patients (10.8%) had positive viral throat cultures. Of these, 27 (50%) were influenza B, 13 (24.1%) were HSV, 7 (12.9%) were RSV, 4 (7.4%) were parainfluenza, and 3 (5.6%) were influenza A. No enteroviruses or adenoviruses were detected, and no multiple infections were detected. Only 22 (4.7%) pilgrims received the influenza vaccine. When the results are applied to the total number of pilgrims in 2003, an estimate of 24,000 cases of influenza is obtained. CONCLUSION: The findings from this study suggest a high incidence of influenza as a cause of upper respiratory tract infection among pilgrims, estimated to be 24,000 cases per Hajj season, excluding those becoming ill from contact with Hajj pilgrims returning home. They also indicate a very low vaccination rate for the influenza vaccine; as well as poor knowledge of its existence. Continued surveillance during the Hajj pilgrimage is necessary. The influenza vaccine should be a priority for those attending the Hajj pilgrimage, and should also be considered for antiviral prophylaxis.  相似文献   
87.
In routine practice, subjective response to antipsychotics is becoming a critical outcome measure among schizophrenia patients. This study sought to compare subjective response to atypical (risperidone and olanzapine) and typical antipsychotic drugs. Using a naturalistic cross-sectional design, we examined subjective response to antipsychotics (satisfaction with medication and subjective tolerability), psychopathology, side effects, emotional distress, and awareness in schizophrenia patients stabilized on atypical (n = 78) and typical (n = 55) drugs. Analysis of variance and multiple regression analysis were applied. We found that atypical drugs were superior to typical antipsychotics in both measures of subjective response, which were positively correlated (r = 0.52, P < 0.001). Poor subjective response was associated with severity of emotional distress, negative, and activation symptoms in the atypical group and with extrapyramidal side effects and positive symptoms in the typical group. Awareness of treatment is a positive factor that accounted for 20% and 34% of variation in the subjective responses to atypical and typical antipsychotic drugs, respectively. Demographic variables, age of onset, illness duration, and adjunctive drugs did not relate significantly to subjective response to antipsychotic drugs. Thus, atypical drugs are characterized by better subjective response compared with typical antipsychotics; their determinants differed considerably. Satisfaction with medication together with subjective tolerability needs to be considered in clinical trials.  相似文献   
88.
BACKGROUND: To identify the risk factors for failed instrumental vaginal delivery, and to compare maternal and neonatal morbidity associated with failed individual and sequential instruments used. DESIGN: A retrospective case-control study. METHODS: From January 1995 to June 2001, there were 39 508 live births at >37 weeks' gestation of which 2628 (6.7%) instrumental vaginal deliveries were performed, 1723 (4.4%) were vacuum extractions and 905 (2.3%) were forceps. A total of 155/2628 (5.9%) patients who had failed instrumental delivery were matched with 204 patients who had successful instrumental delivery. The patients were divided into five groups. Group I (n = 129) had failed vacuum extraction, group II (n = 13) failed forceps, group III (n = 13) failed both (i.e. failed attempt at both instruments sequentially), group IV (n = 138) had successful vacuum extraction and group V (n = 66) successful forceps. RESULTS: The failure rate for vacuum extractions 129/1723 (7.5%) was significantly higher than that for forceps 13/905 (1.4%) [odds ratio (OR) = 5.6, 95% CI 3-10.3]. There were no significant differences in all maternal complications (25.5% vs. 26.6%) between vacuum (groups I and IV) and forceps (groups II and V) assisted deliveries. There were more maternal complications in group III (46.2%) than in groups I (35.7%), II (23.1%) and V (27.3%) that did not reach statistical significance but were significantly higher than in group IV (15.9%, OR = 4.5, 95% CI 1.2-16.9). There was a significantly higher rate of all fetal complications in group III [11/13 (84.6%)] than in groups I [69/129 (53.5%)], II [7/13 (53.8%)], IV [35/138 (25.4%)] and V [22/66 (33.3%)] (OR = 4.8, 95% CI 0.9-19.9). CONCLUSIONS: Applying the instrument at < or =0 fetal station, nulliparous women, history of previous cesarean section and fetal head other than occipitoanterior position were risk factors for failed instrumental delivery. Sequential use of instrumental delivery carries a significantly higher neonatal morbidity than when a single instrument is used.  相似文献   
89.
The first international outbreak of Neisseria meningitidis serogroup W135 occurred in 2000, in direct association with the annual Hajj in Saudi Arabia. In anticipation of the following Hajj, we conducted a survey of oropharyngeal carriage rates of N. meningitidis both pre- and post-pilgrimage in the King Khalid National Guard Hospital (KKNGH) employees preparing to attend the Hajj. These KKNGH employees were native to the Mecca-Jeddah area. Pre-Hajj throat cultures were obtained 1 week prior to Hajj, and post-Hajj cultures within 10 days after completing the Hajj pilgrimage. A total of 327 throat culture samples were collected from 218 persons. Overall meningococcal carriage rate was found to be 4.7%. Serogroup W135 accounted for 40% of all recovered pre-Hajj strains of N. meningitidis. Only one post-Hajj sample was positive for N. meningitidis W135. This high rate of colonization with N. meningitidis serogroup W135 indicates this strain predominates amongst the population indigenous to the Mecca-Jeddah area. This 'nidus' of N. meningitidis W135 is a potential reservoir for future outbreaks. More worrying, there is real risk of future W135 endemicity in this vulnerable local population. These preliminary findings warrant larger surveillance studies examining both transmission and carrier rate acquisition of N. meningitidis in the Mecca-Jeddah area. These vital data are needed to curb further epidemic outbreaks during future Hajj pilgrimages.  相似文献   
90.
Rift Valley fever: an uninvited zoonosis in the Arabian peninsula   总被引:4,自引:0,他引:4  
Rift Valley fever (RVF) is an acute viral disease, affecting mainly livestock but also humans. The virus is transmitted to humans through mosquito bites or by exposure to blood and bodily fluids. Drinking raw, unpasteurized milk from infected animals can also transmit RVF. Routine vaccination of livestock in Africa has been prohibitively expensive, leading to endemicity of RVF in most African countries. Reports in September 2000 first documented RVF occurring outside of Africa in the Kingdom of Saudi Arabia and Yemen. Prior to this outbreak, the potential for RVF spread into the Arabian Peninsula had already been exemplified by a 1977 Egyptian epidemic. This appearance of RVF outside the African Continent might be related to importation of infected animals from Africa. In the most recent outbreak patients presented with a febrile haemorrhagic syndrome accompanied by liver and renal dysfunction. By the end of the outbreak, April 2001 statistics from the Saudi Ministry of Health documented a total of 882 confirmed cases with 124 deaths. Both the severity of disease and the relatively high 14% death rate might be a consequence of underreporting of less severe disease. Travellers to endemic areas may be at risk of acquiring the disease if exposed to animals or their body fluids directly or through mosquito bites. Special education regarding both modes of transmission and the geographical distribution of this disease needs to be given to travellers at risk.  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