全文获取类型
收费全文 | 9800篇 |
免费 | 847篇 |
国内免费 | 95篇 |
专业分类
耳鼻咽喉 | 204篇 |
儿科学 | 354篇 |
妇产科学 | 166篇 |
基础医学 | 1139篇 |
口腔科学 | 202篇 |
临床医学 | 1263篇 |
内科学 | 2045篇 |
皮肤病学 | 89篇 |
神经病学 | 584篇 |
特种医学 | 431篇 |
外国民族医学 | 2篇 |
外科学 | 1265篇 |
综合类 | 297篇 |
一般理论 | 5篇 |
预防医学 | 1078篇 |
眼科学 | 289篇 |
药学 | 849篇 |
中国医学 | 10篇 |
肿瘤学 | 470篇 |
出版年
2023年 | 77篇 |
2022年 | 95篇 |
2021年 | 186篇 |
2020年 | 113篇 |
2019年 | 183篇 |
2018年 | 177篇 |
2017年 | 164篇 |
2016年 | 182篇 |
2015年 | 188篇 |
2014年 | 294篇 |
2013年 | 367篇 |
2012年 | 482篇 |
2011年 | 473篇 |
2010年 | 339篇 |
2009年 | 270篇 |
2008年 | 371篇 |
2007年 | 466篇 |
2006年 | 404篇 |
2005年 | 372篇 |
2004年 | 320篇 |
2003年 | 315篇 |
2002年 | 295篇 |
2001年 | 307篇 |
2000年 | 300篇 |
1999年 | 267篇 |
1998年 | 169篇 |
1997年 | 167篇 |
1996年 | 151篇 |
1995年 | 128篇 |
1994年 | 115篇 |
1993年 | 105篇 |
1992年 | 220篇 |
1991年 | 253篇 |
1990年 | 201篇 |
1989年 | 179篇 |
1988年 | 161篇 |
1987年 | 158篇 |
1986年 | 169篇 |
1985年 | 177篇 |
1984年 | 118篇 |
1983年 | 106篇 |
1981年 | 63篇 |
1979年 | 104篇 |
1978年 | 72篇 |
1976年 | 78篇 |
1974年 | 65篇 |
1973年 | 68篇 |
1972年 | 73篇 |
1971年 | 62篇 |
1970年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
SK Roy AM Tomkins SM Akramuzzaman RH Behrens R Haider D Mahalanabis G Fuchs 《Archives of disease in childhood》1997,77(3):196-200
OBJECTIVE: To evaluate the impact of zinc supplementation on the clinical course, stool weight, duration of diarrhoea, changes in serum zinc, and body weight gain of children with acute diarrhoea. DESIGN: Randomised double blind controlled trial. Children were assigned to receive zinc (20 mg elemental zinc per day) containing multivitamins or control group (zinc-free multivitamins) daily in three divided doses for two weeks. SETTING: A diarrhoeal disease hospital in Dhaka, Bangladesh. PATIENTS: 111 children, 3 to 24 months old, below 76% median weight for age of the National Center for Health Statistics standard with acute diarrhoea. Children with severe infection and/or oedema were excluded. MAIN OUTCOME MEASURES: Total diarrhoeal stool output, duration of diarrhoea, rate of weight gain, and changes in serum zinc levels after supplementation. RESULTS: Stool output was 28% less and duration 14% shorter in the zinc supplemented group than placebo (p = 0.06). There were reductions in median total diarrhoeal stool output among zinc supplemented subjects who were shorter (less than 95% height for age), 239 v 326 g/kg (p < 0.04), and who had a lower initial serum zinc (< 14 mmol/l), 279 v 329 g/kg (p < 0.05); a shortening of mean time to recovery occurred (4.7 v 6.2 days, p < 0.04) in those with lower serum zinc. There was an increase in mean serum zinc in the zinc supplemented group (+2.4 v -0.3 mumol/l, p < 0.001) during two weeks of supplementation, and better mean weight gain (120 v 30 g, p < 0.03) at the time of discharge from hospital. CONCLUSIONS: Zinc supplementation is a simple, acceptable, and affordable strategy which should be considered in the management of acute diarrhoea and in prevention of growth faltering in children specially those who are malnourished. 相似文献
102.
WG Mitchell H Lynn JF Bale MA Maeder SM Donfield B Garg AH Tilton JK Willis TP Bohan 《Pediatrics》1997,100(5):817-824
BACKGROUND: Boys and young men with hemophilia treated with factor infusions before 1985 had a substantial risk of acquiring the human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome. This study was designed to assess the effects of HIV and hemophilia per se on neurological function in a large cohort of subjects with hemophilia, and to investigate the relationships between neurological disease and death during follow-up. METHODS: Three hundred thirty-three boys and young men (207 HIV seropositive and 126 HIV seronegative) were evaluated longitudinally in a multicenter, multidisciplinary study. Neurological history and examination were conducted at baseline and annually for 4 years. The relationship between neurological variables, HIV serostatus, CD4+ cell counts, and vital status at the conclusion of the study was examined using logistic regression models. RESULTS: The risks of nonhemophilia-associated muscle atrophy, behavior change, and gait disturbance increased with time in immune compromised HIV-seropositive subjects compared with HIV seronegative or immunologically stable HIV-seropositive subjects. The risk of behavior change in immune compromised HIV-seropositive hemophiliacs, for example, rose to 60% by year 4 versus 10% to 17% for the other study groups. Forty-five subjects (13.5%), all of whom were HIV seropositive, died by year 4. Subjects who died had had increased risks of hyperreflexia, nonhemophilia-associated muscle atrophy, and behavior change. CONCLUSIONS: These results indicate that immune compromised, HIV-seropositive hemophiliacs have high rates of neurological abnormalities over time and that neurological abnormalities were common among subjects who later died. By contrast, immunologically stable HIV-seropositive subjects did not differ from the HIV-seronegative participants. Hemophilia per se was associated with progressive abnormalities of gait, coordination, and motor function. 相似文献
103.
Kangaroo Care with a ventilated preterm infant 总被引:4,自引:0,他引:4
104.
Guest AR Helvie MA Chan HP Hadjiiski LM Bailey JE Roubidoux MA 《AJR. American journal of roentgenology》2000,175(3):805-810
OBJECTIVE: The purpose of our study was to show that compressed breast thickness on mammograms in overweight and obese women exceeds the thickness in normal-weight women and that increased thickness results in image degradation. SUBJECTS AND METHODS: Three hundred consecutive routine mammograms were reviewed. Patients were categorized according to body mass index. Compression thickness, compressive force, kilovoltage, and milliampere-seconds were recorded. Geometric unsharpness and contrast degradation were calculated for each body mass index category. RESULTS: Body mass index categories were lean (3%), normal (36%), overweight (36%), and obese (25%). Body mass index was directly correlated with compressed thickness. In the mediolateral oblique view, the mean thickness of the obese category exceeded normal thickness by 18 mm (p < 0.01), corresponding to a 32% increase in geometric unsharpness. Mean obese thickness exceeded lean thickness by 33 mm (p < 0.01), corresponding to a 79% increase in unsharpness. Similar trends were observed for the craniocaudal view. In the mediolateral oblique projection, there was an increase of 1.0 kVp (p < 0.01) for obese compared with normal and 1.7 kVp (p < 0.01) between lean and obese, corresponding, respectively, to a 16% and a 25% decrease in image contrast because of scatter and kilovoltage changes. Milliampere-seconds increased by 47% on the mediolateral oblique images in the obese category compared with normal body mass index. CONCLUSION: An increased body mass index was associated with greater compressed breast thickness, resulting in increased geometric unsharpness, decreased image contrast, and greater potential for motion unsharpness. 相似文献
105.
David B Preen Belinda E S Bailey Alan Wright Peter Kendall Martin Phillips Joseph Hung Randall Hendriks Annette Mather Elizabeth Williams 《International journal for quality in health care》2005,17(1):43-51
OBJECTIVE: To determine the impact of a hospital-coordinated discharge care plan, involving a multidisciplinary team of primary health care providers, on hospital length of stay, quality of life, and both patient and general practitioner inclusion in, and satisfaction with, discharge procedures. DESIGN: This investigation comprised a prospective, randomized, controlled, clinical trial. SETTING: This multicentre and cross-jurisdictional study focused on areas of tertiary and primary health care as well as community allied health in Western Australia. PARTICIPANTS: Patients (n = 189) with chronic cardiorespiratory diagnoses were recruited from respiratory, cardiovascular, and general medical wards at two tertiary hospitals. INTERVENTION: Subjects were randomly assigned to one of two groups. Intervention group patients received a discharge care plan in accordance with that outlined in the Australian Enhanced Primary Care Package, completed before discharge and sent to the patient's general practitioner and other community service providers for review. Control patients were discharged under existing hospital processes. Outcome measures. Patients and general practitioners were surveyed pre-discharge and 7 days post-discharge for quality of life and opinion of discharge procedures. Hospital length of stay was also determined. RESULTS: Significant improvements in discharge planning involvement, health service access, confidence with discharge procedures, and opinion of discharge based on previous experience were seen for patients who received the discharge care plan. Further, improved perceptions of mental quality of life were observed within the first week post-discharge for intervention patients. Length of stay showed no difference between groups. Extent and speed of hospital-general practitioner communication were significantly improved via the intervention. CONCLUSIONS: Our results indicate that a multidisciplinary discharge care plan, initiated before separation, improves quality of life, involvement, and satisfaction with discharge care, and hospital-general practitioner integration. As such, it possesses benefits over current Western Australian hospital discharge procedures for the care of chronically ill populations. 相似文献
106.
Bailey SH Shapiro SB Mone MC Saffle JR Morris SE Barton RG 《American journal of surgery》2000,180(6):517-21; discussion 521-2
BACKGROUND: Current standard of care dictates that central venous catheter (CVC) insertion should be followed by an immediate chest radiograph to confirm appropriate position and rule out complications. We hypothesized that a subset of monitored intensive care unit patients exists that is at low risk for complications and might safely have radiographic evaluation of line placement deferred until the next scheduled radiograph. METHODS: Data regarding patient and procedural characteristics were obtained prospectively for 184 CVC placed between March 1, 1998, and June 30, 1999. Retrospective data regarding complications were obtained by chart review for an additional 174 CVC placed during the study period but for which data sheets were not completed. All procedures were followed by chest radiography. RESULTS: We documented a complication rate of 9% with the vast majority (25 of 31, 81%) of complications consisting of incorrect positioning. The number of needle passes was greater in the group suffering pneumothorax and arterial puncture than the uncomplicated group (5.6 versus 1.9, P = 0.008). "Straightforward" operator gestalt (P = 0.04) and number of needle passes <3 (P = 0.03) were factors correlating with the absence of complications. These factors had negative predictive values of 94% and 96%, respectively. CONCLUSION: Placement of CVC is safe in experienced hands. In monitored intensive care unit patients who undergo a "straightforward" procedure with <3 needle passes, chest radiograph can be safely deferred until the next scheduled examination. 相似文献
107.
108.
Mariani J Ou R Bailey M Rowland M Nagley P Rosenfeldt F Pepe S 《The Journal of thoracic and cardiovascular surgery》2000,120(4):660-667
BACKGROUND: Recovery of cardiac function after cardiac surgery and other interventional cardiac procedures in elderly patients is inferior to that in younger patients, suggesting that the aged myocardium is more sensitive to ischemia and other stresses. Although convincing data from animal studies of senescence now exist, there is a dearth of controlled in vitro studies that examine the specific response of aged human myocardium to the stress of hypoxia or ischemia. OBJECTIVE: We sought to determine the effect of age on the capacity of human atrial trabeculae to recover contractile function after in vitro hypoxic or ischemic stress. METHODS: Atrial pectinate trabeculae were dissected from the tip of 58 right atrial appendages harvested during an operation in patients aged between 34 and 89 years and electrically stimulated at 1 Hz in oxygenated Ringer's solution at 37 degrees C. Tissues experienced 30 minutes of either hypoxia (N(2) and perfusate) or simulated ischemia (humidified N(2) without perfusate) and were returned to normoxia for recovery of function for 30 minutes. Developed force and other contractile variables were determined during each period. RESULTS: Under normoxic conditions, no significant age difference was observed for any contractile function variable. However, after hypoxia, the old (70-89 years) and intermediate age groups (60-69 years) showed reduced recovery of developed force (48.5% +/- 22.2% [n = 11] and 44.9% +/- 19% [n = 12], respectively) compared with that found (66.4% +/- 19.7% [n = 15]) in the younger (34-59 years) group (mean +/- SD, P =.02). Similarly, after simulated ischemia, the groups of 70- to 89-year-old and 60- to 69-year-old subjects showed reduced recovery of developed force (35.7% +/- 17% [n = 5] and 51.1% +/- 11.8% [n = 9], respectively) compared with that found (68.2% +/- 10.4% [n = 6]) in the group of 34- to 59-year-old subjects (P =.01). Multivariable analysis, comparing 20 factors of surgical patient characteristics and recovery of developed force, found that only age (P =.01) and hypertension (P =.01) were predictors of reduced recovery of developed force after either hypoxia or simulated ischemia. CONCLUSIONS: In aged human atrial myocardium, the capacity to recover contractile function after in vitro hypoxia or simulated ischemia is reduced compared with the younger myocardium of mature adults. These findings suggest that enhanced myocardial protective strategies may be indicated for elderly patients undergoing cardiac surgery. 相似文献
109.
Our understanding of the actions of extracellular ATP in controlling kidney function via stimulation of P2 receptors is still at an early stage. Recently, several groups, including our own, have begun to address this subject: in this brief review, we discuss some of these effects and speculate on likely function of extracellular nucleotides in the kidney. 相似文献
110.