全文获取类型
收费全文 | 931852篇 |
免费 | 66178篇 |
国内免费 | 1342篇 |
专业分类
耳鼻咽喉 | 12957篇 |
儿科学 | 24358篇 |
妇产科学 | 23232篇 |
基础医学 | 132872篇 |
口腔科学 | 28246篇 |
临床医学 | 80528篇 |
内科学 | 183215篇 |
皮肤病学 | 19226篇 |
神经病学 | 72166篇 |
特种医学 | 36797篇 |
外国民族医学 | 79篇 |
外科学 | 152061篇 |
综合类 | 18042篇 |
现状与发展 | 1篇 |
一般理论 | 234篇 |
预防医学 | 61735篇 |
眼科学 | 21307篇 |
药学 | 72528篇 |
3篇 | |
中国医学 | 2162篇 |
肿瘤学 | 57623篇 |
出版年
2018年 | 8959篇 |
2017年 | 7025篇 |
2016年 | 7758篇 |
2015年 | 8856篇 |
2014年 | 11980篇 |
2013年 | 17490篇 |
2012年 | 24073篇 |
2011年 | 25024篇 |
2010年 | 14798篇 |
2009年 | 14261篇 |
2008年 | 24590篇 |
2007年 | 25680篇 |
2006年 | 26470篇 |
2005年 | 25417篇 |
2004年 | 24551篇 |
2003年 | 23598篇 |
2002年 | 23142篇 |
2001年 | 54724篇 |
2000年 | 56541篇 |
1999年 | 46947篇 |
1998年 | 10730篇 |
1997年 | 9465篇 |
1996年 | 9595篇 |
1995年 | 8926篇 |
1994年 | 8278篇 |
1993年 | 7593篇 |
1992年 | 35487篇 |
1991年 | 33911篇 |
1990年 | 32734篇 |
1989年 | 31869篇 |
1988年 | 28991篇 |
1987年 | 28249篇 |
1986年 | 26288篇 |
1985年 | 25144篇 |
1984年 | 17832篇 |
1983年 | 15141篇 |
1982年 | 7795篇 |
1981年 | 6771篇 |
1979年 | 15781篇 |
1978年 | 10598篇 |
1977年 | 9052篇 |
1976年 | 7871篇 |
1975年 | 8628篇 |
1974年 | 10466篇 |
1973年 | 9858篇 |
1972年 | 9357篇 |
1971年 | 8852篇 |
1970年 | 8426篇 |
1969年 | 7923篇 |
1968年 | 7200篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
M. Pesonen M. J. T. Kallio A. Ranki M. A. Siimes 《Clinical and experimental allergy》2006,36(8):1011-1018
BACKGROUND: Exclusive breastfeeding for the first 6 months is recommended by the World Health Organization and considered allergy preventive. However, it is not known whether prolonging exclusive breastfeeding for over 6 months provides further benefit in allergy prevention. OBJECTIVE: The aim of this prospective 20-year follow-up study was to find out whether the allergy protective effect can be enhanced by prolonging strictly exclusive breastfeeding for > or =9 months of age. A total of 200 unselected healthy newborns were enrolled in the study. Their mothers were encouraged to maintain exclusive breastfeeding for as long as possible. The number of infants on strictly exclusive breastfeeding was 167 at 2, 116 at 6, 36 at 9 and 7 at 12 months of age. Of the 200 infants, 42% had a family history of allergy. The children were re-assessed at ages 5 (n=163), 11 (n=150) and 20 years (n=164) with clinical examination, skin prick testing, and parental and personal structured interviews. RESULTS: Exclusive breastfeeding prolonged for > or =9 months was associated with atopic dermatitis (P=0.002) and symptoms of food hypersensitivity (P=0.02) at age 5 years, and with symptoms of food hypersensitivity at age 11 years (P=0.01), in children with a family history of allergy. CONCLUSION: Prolonging strictly exclusive breastfeeding for > or =9 months was not helpful in atopy prevention, instead, it was associated with increased atopic dermatitis and food hypersensitivity symptoms in childhood. 相似文献
942.
943.
944.
W G Mouton J R Bessell T Zehnder R Wirth M Naef H E Wagner 《European journal of vascular and endovascular surgery》2005,29(3):313-315
OBJECTIVE: Prospectively to compare lymphatic drainage after ultrasonic dissection, an electrocoagulation technique and sharp dissection in the groin during surgery for recurrent sapheno-femoral incompetence. DESIGN: Prospective, randomised study comparing three surgical techniques. METHODS: Thirty-six consecutive patients undergoing surgery for recurrent sapheno-femoral incompetence were randomised. Twelve patients underwent dissection with ultrasound, 12 with electrocoagulation and 12 controls had sharp dissection with ligation of scar and lymphatic tissue using absorbable suture material. RESULTS: The mean drain output per patient was 13.5 ml in the ultrasonic group, 15.4 ml in the electrocoagulation group and 8.3 ml in the suture ligation group. Six minor cases of lymphatic leakage occurred in the ultrasonic group. This resulted in no clinical problem. There were no other significant differences between the three groups. CONCLUSIONS: There is no detectable advantage for the use of ultrasound or electrocoagulation in recurrent saphenous high ligation compared to sharp dissection. 相似文献
945.
Michael D. Lara M.D. Matthew T. Baker M.D. Christopher J. Larson PA-C R.D. Michelle A. Mathiason M.S. Pamela J. Lambert R.N. Shanu N. Kothari M.D. 《Surgery for obesity and related diseases》2005,1(1):597-21
BACKGROUND: There is no consensus regarding the optimal rate of follow-up in the post-bariatric surgery patient population. METHODS: The records of all patients who underwent laparoscopic Roux-en-Y gastric bypass from 2001 to 2003 were reviewed. Using patient zip codes, travel distances were calculated between the patients' places of residence and our clinic. Patients were then assigned to 1 of 3 cohorts according to the following distances: (1) < 50 miles, (2) 50 to 100 miles, and (3) > 100 miles. Patient compliance with follow-up appointments at 3 weeks, 3 months, 6 months, 9 months, and 12 months was analyzed. Linear trends were identified using the Mantel-Haenszel test. Age and sex were analyzed as possible predictors of compliance using the chi(2) test. P values < .05 were considered statistically significant. RESULTS: The study group comprised 150 patients (127 females and 23 males). The 3 cohorts contained 115, 21, and 14 patients, respectively. All patients in each cohort were compliant with the 3-week follow-up appointment. Although there were differences in compliance between cohorts at each of the remaining appointments, only the 9-month (70.3% vs 61.9% vs 35.7%) visit showed statistical significance (P = .035). The 6-month visit trended toward significance (85.2% vs 76.2% vs 64.3%; P = .088). Males were more likely to be compliant with the 12-month follow-up (P = .040). When controlling for sex, travel distance was also a predictor of compliance at this follow-up visit (P = .024). Age was not predictive of compliance (P = .827). CONCLUSION: Based on our findings, we conclude that travel distance from the clinic does not significantly affect compliance at the initial follow-up, 3-month, and 12-month appointments. However, distance does tend to affect compliance at the 6-month appointment and significantly affects compliance at the 9-month appointment. Males are more likely to be compliant at the 12 month follow-up visit. We must continue to strive for 100% follow-up in our post-bariatric surgery patients. 相似文献
946.
947.
948.
P31
The relationship between the relative amount of Porphyromonas gingivalis in saliva and halitosis
Objectives Porphyromonas gingivalis is one of the microorganisms that most actively produce CH3 SH and we have reported that subjects with P . gingivalis have higher CH3 SH levels than subjects without P . gingivalis . However, little is known about the relationship between P . gingivalis levels in saliva and the condition of oral malodor. In this study, we evaluated the association between the relative amount of P . gingivalis in saliva and halitosis in mouth air.
Methods All of the subjects were patients at the Preventive Dentistry and Breath Odor Clinic of Kyushu Dental College, where they received a periodontal examination. Volatile sulfur compounds (VSC: hydrogen sulfide and methyl mercaptan) were measured using gas chromatography. Saliva samples were collected in a sterile plastic tube over a period of 5 min while the subject chewed on paraffin wax, and were then immediately stored at –80°C until use. Template DNA was obtained from the stored saliva using an Easy-DNA Kit (Invitrogen, CA, USA) according to the manufacturer's instructions. Conventional PCR assays were used to confirm the presence of P . gingivalis . A 5' nuclease TaqMan PCR was used to quantify P . gingivalis in saliva. The relative numbers of bacteria were measured using the comparative threshold cycle method.
Results We found a quantitative relationship between the P . gingivalis levels in saliva and the condition of halitosis in mouth air.
Conclusion We analyzed the relationship between the relative amount of P . gingivalis in saliva and oral malodor. 相似文献
Methods All of the subjects were patients at the Preventive Dentistry and Breath Odor Clinic of Kyushu Dental College, where they received a periodontal examination. Volatile sulfur compounds (VSC: hydrogen sulfide and methyl mercaptan) were measured using gas chromatography. Saliva samples were collected in a sterile plastic tube over a period of 5 min while the subject chewed on paraffin wax, and were then immediately stored at –80°C until use. Template DNA was obtained from the stored saliva using an Easy-DNA Kit (Invitrogen, CA, USA) according to the manufacturer's instructions. Conventional PCR assays were used to confirm the presence of P . gingivalis . A 5' nuclease TaqMan PCR was used to quantify P . gingivalis in saliva. The relative numbers of bacteria were measured using the comparative threshold cycle method.
Results We found a quantitative relationship between the P . gingivalis levels in saliva and the condition of halitosis in mouth air.
Conclusion We analyzed the relationship between the relative amount of P . gingivalis in saliva and oral malodor. 相似文献
949.
The aim of the study was to map out the pattern of referral of patients with gestational trophoblastic disease (GTD) presenting to a large tertiary referral centre, from the health districts of KwaZulu Natal province, South Africa, and to determine the demographic variables in the presentation of the disease. This retrospective study reviewed the clinical charts of 98 patients managed at the combined gynaecology/oncology clinic over a 5-year period. The types of GTD included molar pregnancy 50 (51%), choriocarcinoma 46 (46%) and placental site trophoblastic tumour 2 (2%). The majority of patients were referred by the district or regional hospitals (63.3%), followed by self-referrals (23.5%). There were 51 (52%) patients from eThekwini health district and only 25 patients (25.4%) from the Northern health districts. With regard to previous pregnancy state, 63.3% (n = 62) had term pregnancy, 13.3% (n = 13) had previous miscarriage and 2% (n = 2) had previous ectopic pregnancy. Five patients (5.1%) had previous molar pregnancy. We did not find a trend of referral of patients being predominantly from the Northern regions of KwaZulu Natal. 相似文献
950.
Fluconazole resistance in AIDS patients. 总被引:14,自引:0,他引:14