全文获取类型
收费全文 | 16288篇 |
免费 | 1549篇 |
国内免费 | 231篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 660篇 |
妇产科学 | 234篇 |
基础医学 | 870篇 |
口腔科学 | 518篇 |
临床医学 | 1973篇 |
内科学 | 2001篇 |
皮肤病学 | 89篇 |
神经病学 | 1510篇 |
特种医学 | 191篇 |
外科学 | 1010篇 |
综合类 | 1726篇 |
现状与发展 | 1篇 |
预防医学 | 4836篇 |
眼科学 | 96篇 |
药学 | 790篇 |
29篇 | |
中国医学 | 370篇 |
肿瘤学 | 1086篇 |
出版年
2024年 | 44篇 |
2023年 | 348篇 |
2022年 | 517篇 |
2021年 | 881篇 |
2020年 | 796篇 |
2019年 | 721篇 |
2018年 | 674篇 |
2017年 | 683篇 |
2016年 | 636篇 |
2015年 | 601篇 |
2014年 | 1107篇 |
2013年 | 1299篇 |
2012年 | 985篇 |
2011年 | 1071篇 |
2010年 | 802篇 |
2009年 | 889篇 |
2008年 | 896篇 |
2007年 | 834篇 |
2006年 | 620篇 |
2005年 | 501篇 |
2004年 | 430篇 |
2003年 | 377篇 |
2002年 | 309篇 |
2001年 | 253篇 |
2000年 | 235篇 |
1999年 | 182篇 |
1998年 | 172篇 |
1997年 | 137篇 |
1996年 | 117篇 |
1995年 | 130篇 |
1994年 | 92篇 |
1993年 | 92篇 |
1992年 | 83篇 |
1991年 | 70篇 |
1990年 | 57篇 |
1989年 | 63篇 |
1988年 | 56篇 |
1987年 | 35篇 |
1986年 | 30篇 |
1985年 | 58篇 |
1984年 | 37篇 |
1983年 | 25篇 |
1982年 | 24篇 |
1981年 | 22篇 |
1980年 | 16篇 |
1979年 | 16篇 |
1978年 | 12篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 288 毫秒
41.
A comparison of 121 mature-age and 270 normal-age entrants who graduated from the University of Queensland Medical School between 1972 and 1987 shows that mature-age entrants are some 7 years older, are more likely to come from public (state) schools and less likely to have parents in professional/technical occupations. Otherwise, the two groups were similar in terms of gender, marital status, number of children, ethnic background and current practice location. The educational background of mature-age entrants prior to admission includes 44.6% with degrees in health-science areas and 31.4% with degrees in non-health areas. Reasons for delayed entry of mature-age entrants include late consideration of medicine as a career (34.7%), financial problems (31.4%), dissatisfaction with previous career (30.6%), poor academic results (19.8%), or a combination of the above factors. Motivations to study medicine include family influences (more so in normal-age entrants), altruistic reasons (more so in mature-age entrants) and a variety of personal/social factors such as intellectual satisfaction, prestige and financial security (similar for both groups) and parental expectations (more so in normal-age entrants). Mature-age entrants experienced greater stress throughout the medical course, especially with regard to financial difficulties, loneliness/isolation from the students and family problems (a greater proportion were married with children). While whole-course grades were similar in both groups, normal-age entrants tended to win more undergraduate honours/prizes and postgraduate diplomas/degrees, including specialist qualifications. Practice settings were similar in terms of group private practice, hospital/clinic practice or medical administration, but there was a greater proportion of mature-age entrants in solo private practice, and a smaller proportion in teaching/research. If given the time over, some two-thirds of both groups would choose medicine as a career. Reasons for job satisfaction include helping patients, intellectual stimulation and financial rewards. Reasons for dissatisfaction include pressure of work, red-tape/paperwork, 'doctor-bashing', long working hours, emotional strain, financial pressure, unfulfilled career expectations and irritation with trivial medical complaints. 相似文献
42.
Boeschoten E. W.; Schrijver J.; Krediet R. T.; Schreurs W. H. P.; Arisz L. 《Nephrology, dialysis, transplantation》1988,3(2):187-193
Concentrations of the vitamins B1, B2, B6, B12, C, folic acid,A, E and ß-carotene were determined in blood and 24-hdialysate in 44 CAPD patients. Twenty-five of these patientswere studied during chronic treatment (mean 313 days, range601034 days). Nineteen patients were studied during training.In a longitudinal study, 11 patients were analysed again after77507 (mean 238) days. In both patient groups a considerable portion of patients (11%64%)had blood concentrations indicative of a deficiency of the vitaminsB1, B6, C and folic acid. The average concentrations of thesevitamins were normal in both groups. The only abnormal findingwas the mean EGOT activity being deficient in patients on chronictreatment. Mean concentrations of vitamin A were above normalin both groups. In the longitudinal study a significant increaseof vitamin B2 and a decrease of vitamin B6 in blood was found. When compared to 24-h excretion in normal urine, loss with 24-hdialysate was low for vitamin B1, normal to relatively highfor vitamin B2 and B6, but extremely high for vitamin C andfolic acid. The vitamins B12, A, E and carotenoids were hardlydetectable in the dialysate. In ten other patients the effect of daily supplementation with2 mg vitamin B6, 100mg vitamin C and 400 µg folic acidwas analysed during a 16-week period. In all patients a significantincrease in blood concentrations was obtained. It is concludedthat these dosages were sufficient to maintain a normal statusof these vitamins in CAPD patients. 相似文献
43.
H. -J. Möller H. M. van Praag B. Aufdembrinke P. Bailey T. R. E. Barnes J. Beck H. Bentsen F. X. Eich L. Farrow W. W. Fleischhacker J. Gerlach K. Grafford B. Hentschel A. Hertkorn S. Heylen Y. Lecrubier J. P. Leonard P. McKenna W. Maier V. Pedersen A. Rappard W. Rein J. Ryan M. Sloth Nielsen R. -D. Stieglitz G. Wegener J. Wilson 《Psychopharmacology》1994,115(1-2):221-228
There is little agreement about the methodology of clinical trials of antipsychotic drugs in patients with negative symptoms. A literature review revealed wide variation in experimental design, rating scales and study duration. This reflects differing views as to the definition and response to treatment of negative symptoms. Some degree of standardization would improve comparability of studies and aid the development of new compounds. Patients included in such studies should have displayed negative symptoms for at least 6 months. Depressive symptoms, positive schizophrenic symptoms and extrapyramidal signs may all influence or be confused with negative symptoms and may respond to treatment; they should be at a low level at baseline and should be measured during the study period. Studies should last at least 8 weeks. Several scales are available for measuring negative symptoms and are reviewed; a global impression score should be used additionally. 相似文献
44.
目的 : 海岛学生饮食结构中含有碘丰富的海产品。本研究旨在了解海岛学生的碘营养状况 ,评价食盐补碘的利弊。方法 : 对定海农村 (食用碘盐 )和岱山农村 (不食用碘盐 )的学校中随机抽取的 1 2个班级 ,对碘盐组和非碘盐组的饮食碘摄入和尿碘水平等变量进行描述 ,并分别以尿碘和甲状腺肿率为应变量进行单因素和多因素回归分析。结果 : 碘盐组除碘盐外每日碘摄入量中位数为 1 84μg,而不食用加碘盐的组为 1 0 5 μg,两组饮食碘摄入有显著性差异 (u=4.71 0 ,P=0 .0 0 0 ) ,而尿碘水平在食用碘盐组和不食用碘盐组分别为 1 6 9μg/L和 1 2 9μg/L,两组间有显著性差异 (u=6 .3 0 2 ,P=0 .0 0 0 )。多因素分析中性别和是否食用碘盐对尿碘水平有显著性意义 (P<0 .0 5 ,OR值分别为 0 .76 5 ,1 .93 3 )。甲状腺肿学生和正常学生的饮食碘和尿碘无统计学差异 (P>0 .0 5 )。Poisson回归分析中性别和是否食用碘盐对甲状腺肿率有影响 (P<0 .0 5 ,OR值分别为2 .2 5 ,3 .5 2 )。结论 : 舟山海岛学生要注意补碘过程中可能出现的碘过量问题。 相似文献
45.
Y. Spyckerelle B. Herbeth J.-P. Deschamps ‡ 《Journal of human nutrition and dietetics》1992,5(3):161-168
The dietary history method was used to determine the total energy and macronutrient intake, the distribution of daily energy from the different meals and the energy contribution of various food groups, in a population of 299 boys, aged between 10 and 15 years. The effects of age, the social status of the father (SPS), the ponderal index, the importance of breakfast or lunch, and the level of energy intake on dietary indicators, were studied. In our population, energy intake increased with increasing age but the energy contribution of macronutrients did not vary. The diet of boys whose fathers were in the upper SPS classes differed from the diet of those boys whose fathers were manual workers: for example they consumed less energy and pastries, but more animal protein (in percentage of energy intake), more dairy products, and more fruit. The ponderal index was negatively related to energy intake but positively related to protein intake, especially from meat and meat products. The energy intake from protein, animal protein and the energy contribution of dairy products, meat and meat products, fish and vegetables was lower among large eaters than among small eaters. The energy contribution of pastries, sugar and sweets was higher among large eaters.
Similarily, the energy intake from morning and evening snacks was also higher among large eaters. It should be noted that boys who had a substantial breakfast took in less energy from all other meals (including snacks and main meals). Such informaton is necessary in order to develop an effective health programme. 相似文献
Similarily, the energy intake from morning and evening snacks was also higher among large eaters. It should be noted that boys who had a substantial breakfast took in less energy from all other meals (including snacks and main meals). Such informaton is necessary in order to develop an effective health programme. 相似文献
46.
Daily nutrient intake represents a modifiable determinant of nutritional status in chronic haemodialysis patients. 总被引:2,自引:0,他引:2
Vincenzo Bellizzi Biagio R Di Iorio Vincenzo Terracciano Roberto Minutolo Carmela Iodice Luca De Nicola Giuseppe Conte 《Nephrology, dialysis, transplantation》2003,18(9):1874-1881
BACKGROUND: In maintenance haemodialysis patients, daily food intake is changeable; however, its relationship with nutritional status is unexplored. This study aimed to evaluate the isolated, long-term effect of daily nutrient intake on nutritional status in haemodialysis patients. METHODS: We performed a prospective 1-year controlled study in 27 chronic haemodialysis patients, without recognized risk factors for malnutrition. Each day for 1 week, four times in the year, we measured protein nitrogen appearance, and assessed dietary protein (DPI) and energy (DEI) intake from dietary diaries. We compared the nutritional outcome of patients spontaneously reducing nutrient intake below the threshold of 0.8 g/kg body weight/day for DPI and 25 kcal/kg body weight/day for DEI during the week (LOW, n = 8), with controls at adequate nutrient intake (CON, n = 19). An interventional 6-month study was then carried out in LOW to verify the cause-effect relationship. RESULTS: All patients showed a day-by-day reduction of whole nutrient intake during interdialytic period, which was mostly relevant in the third interdialytic day (L3). During the 1-year study, even in the presence of adequate dialysis dose and normal inflammatory indexes, body weight (68.0 +/- 5.5 to 65.8 +/- 5.9 kg), serum albumin (3.96 +/- 0.07 to 3.66 +/- 0.06 g/dl) and creatinine (9.2 +/- 1.1 to 8.1 +/- 0.7 mg/dl) significantly decreased in LOW but not in CON. Diaries evidenced in LOW a reduced number of meals at L3 that was explained by the fear of excessive interdialytic weight gain. During the interventional study, daily DPI and DEI increased at L3; this was associated with a significant increment of body weight, and serum albumin and creatinine levels. CONCLUSIONS: In maintenance haemodialysis patients the persistent, marked reduction of daily nutrient intake, even if limited to a single day of the week, is an independent determinant of reversible impairment of nutritional status. 相似文献
47.
48.
49.
Jin H. Han MD MSc Karen F. Miller RN MPA Alan B. Storrow MD 《Academic emergency medicine》2007,14(3):228-233
Background: Elder patients with acute coronary syndromes (ACS) are less likely to receive cardiac catheterization. The reasons for this are unclear.
Objectives: To assess whether elder patients who had a documented history of dementia, lived in extended care facilities, or had do not intubate–do not resuscitate (DNR-DNI) advance directives were less likely to receive cardiac catheterization, despite having ACS with high-risk features.
Methods: This was a medical record review conducted at an urban teaching hospital. DNR-DNI status before hospitalization, extended care facility (nursing home or assisted living) residence, and a previous diagnosis of dementia were obtained from the medical record. Patients 65 years and older who presented to the emergency department with acute myocardial infarction or with unstable angina with ST segment deviation were included. Univariate and multivariate logistic regression were performed, and odds ratios (ORs) were reported with their 95% confidence intervals (CIs).
Results: Of the 201 eligible patients, 66 (32.8%) patients did not undergo cardiac catheterization. In the univariate analysis, patients who had dementia, resided in extended care facilities, or were DNR-DNI were less likely to receive cardiac catheterization. Only extended care facility residence (OR, 0.18; 95% CI = 0.04 to 0.83) and DNR-DNI status (OR, 0.19; 95% CI = 0.04 to 0.92) remained significantly associated with decreased cardiac catheterization in the multivariate analysis.
Conclusions: Elder patients with ACS residing in extended care facilities or who are DNR-DNI are less likely to receive cardiac catheterization. Future studies concerning the quality of ACS care for elders should take these variables into account. 相似文献
Objectives: To assess whether elder patients who had a documented history of dementia, lived in extended care facilities, or had do not intubate–do not resuscitate (DNR-DNI) advance directives were less likely to receive cardiac catheterization, despite having ACS with high-risk features.
Methods: This was a medical record review conducted at an urban teaching hospital. DNR-DNI status before hospitalization, extended care facility (nursing home or assisted living) residence, and a previous diagnosis of dementia were obtained from the medical record. Patients 65 years and older who presented to the emergency department with acute myocardial infarction or with unstable angina with ST segment deviation were included. Univariate and multivariate logistic regression were performed, and odds ratios (ORs) were reported with their 95% confidence intervals (CIs).
Results: Of the 201 eligible patients, 66 (32.8%) patients did not undergo cardiac catheterization. In the univariate analysis, patients who had dementia, resided in extended care facilities, or were DNR-DNI were less likely to receive cardiac catheterization. Only extended care facility residence (OR, 0.18; 95% CI = 0.04 to 0.83) and DNR-DNI status (OR, 0.19; 95% CI = 0.04 to 0.92) remained significantly associated with decreased cardiac catheterization in the multivariate analysis.
Conclusions: Elder patients with ACS residing in extended care facilities or who are DNR-DNI are less likely to receive cardiac catheterization. Future studies concerning the quality of ACS care for elders should take these variables into account. 相似文献
50.
广州市4770名小学生营养状况调查及分析 总被引:2,自引:1,他引:1
目的了解广州市东山区4770名小学生的营养状况。方法对2005年广州市东山区农林街的小学生健康检查结果进行分析和评价。结果广州市东山区各年龄组小学生营养不良和肥胖的比例均较高,其中男生肥胖的检出率明显高于女生,女生营养不良的比例明显高于男生,贫血患病率明显低于国内同类研究结果。结论整个社会应加强联系与协作,开展有效的健康教育,倡导良好的健康习惯,加强体育锻炼,改善小学生的营养状况。 相似文献