全文获取类型
收费全文 | 3431648篇 |
免费 | 250781篇 |
国内免费 | 9211篇 |
专业分类
耳鼻咽喉 | 46433篇 |
儿科学 | 113179篇 |
妇产科学 | 95725篇 |
基础医学 | 481703篇 |
口腔科学 | 94756篇 |
临床医学 | 314599篇 |
内科学 | 673611篇 |
皮肤病学 | 81386篇 |
神经病学 | 282352篇 |
特种医学 | 130777篇 |
外国民族医学 | 1111篇 |
外科学 | 512345篇 |
综合类 | 74062篇 |
现状与发展 | 7篇 |
一般理论 | 1334篇 |
预防医学 | 267484篇 |
眼科学 | 77700篇 |
药学 | 248274篇 |
8篇 | |
中国医学 | 7250篇 |
肿瘤学 | 187544篇 |
出版年
2019年 | 27431篇 |
2018年 | 38478篇 |
2017年 | 29543篇 |
2016年 | 33948篇 |
2015年 | 38233篇 |
2014年 | 53270篇 |
2013年 | 79975篇 |
2012年 | 106713篇 |
2011年 | 113197篇 |
2010年 | 67821篇 |
2009年 | 64739篇 |
2008年 | 105213篇 |
2007年 | 111626篇 |
2006年 | 113478篇 |
2005年 | 109196篇 |
2004年 | 104721篇 |
2003年 | 100983篇 |
2002年 | 97565篇 |
2001年 | 165392篇 |
2000年 | 169447篇 |
1999年 | 142484篇 |
1998年 | 41206篇 |
1997年 | 36692篇 |
1996年 | 36715篇 |
1995年 | 35506篇 |
1994年 | 32418篇 |
1993年 | 30337篇 |
1992年 | 110006篇 |
1991年 | 105600篇 |
1990年 | 102324篇 |
1989年 | 98569篇 |
1988年 | 90419篇 |
1987年 | 88582篇 |
1986年 | 82967篇 |
1985年 | 79400篇 |
1984年 | 59539篇 |
1983年 | 50464篇 |
1982年 | 30173篇 |
1981年 | 26900篇 |
1979年 | 52625篇 |
1978年 | 37246篇 |
1977年 | 31388篇 |
1976年 | 29242篇 |
1975年 | 30829篇 |
1974年 | 36711篇 |
1973年 | 35094篇 |
1972年 | 32984篇 |
1971年 | 30503篇 |
1970年 | 28346篇 |
1969年 | 26991篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
This was a retrospective observational study of 11 consecutive patients of major primary postpartum haemorrhage (PPH) who had the B-Lynch suture at the time of caesarean section, performed between 1 March 2001 and 31 March 2004 at a teaching hospital in Scotland. Case-note review was performed in 123 patients, who had major primary PPH to identify patients who had B-Lynch sutures at the time of caesarean section. The patient's age, parity, gestation of pregnancy at which the B-Lynch suture was performed, the indication for caesarean section and the cause of primary major PPH were recorded. The operative details, intraoperative and immediate postoperative complications and the need for subsequent hysterectomy were noted. The patients were followed-up with clinic visits at 6 weeks and any further hospital referral for late postoperative complications and whether subsequent successful pregnancy was achieved, were documented. The incidence of major PPH in our centre was 0.5% of the total deliveries, of which 11 cases had the B-Lynch suture applied at the time of caesarean section. The patients were aged between 25 and 38 years old (mean 31 years). Parity ranged from 0 to 1 and the gestational age at which the procedure was performed ranged from 34 to 41 weeks (mean 38 weeks). Ten operations (91%) were performed by senior registrars supervised by the consultant on call and one (9%) case was performed by a consultant on call. All cases had the B-Lynch sutures performed for major primary PPH caused by uterine atony at the time of caesarean section. The weight of the babies delivered ranged between 2,110 - 4,820 g (mean 3,500 g). The total blood loss at surgery ranged from 2,000 - 10,000 ml (mean 3,500 ml). Only three patients (28%) required hysterectomy. All the patients made a good postoperative recovery. The hospital stay ranged from 4 - 24 days (mean 8 days). The patient who remained in hospital for 24 days did so because her baby was admitted into the neonatal unit. All the patients were reviewed 6 weeks postnatally. There was no significant morbidity. A subsequent successful pregnancy has been achieved in one patient. 相似文献
994.
Multiple intrahippocampal injections of gallamine impair performance of a representational memory task in rats. The binding of [3H]-(-)-quinuclidinyl benzilate (QNB) to rat brain sections was measured to determine if changes in receptor binding were associated with the deleterious effects of gallamine. [3H]-(-)-QNB binding to sections taken from gallamine-injected animals was compared with binding in saline-injected control animals. Autoradiographic analyses indicated an increase in [3H]-(-)-QNB binding sites within all layers of the cerebral cortex and in the superior colliculus in gallamine-treated animals as compared to saline-injected controls. Significant increases were noted in cortical layers IV and V (P less than 0.025) in gallamine-treated animals. No significant changes (P greater than 0.05) in the number of binding sites were observed in the hippocampus, neostriatum or various thalamic nuclei. The ability of unlabeled pirenzepine, gallamine and carbamylcholine to inhibit 0.2 nM [3H]-(-)-QNB binding also was measured to determine changes in the distribution of receptor subtypes. No significant changes were observed in any brain region for the binding of the selective antagonists pirenzepine and gallamine or the agonist carbamyl-choline. Although other possibilities are considered, the data suggest that an increase in the number of muscarinic receptors may contribute to the observed behavioral deficits associated with long-term gallamine treatment. 相似文献
995.
996.
Janet M Powell Sonya L Griffith Elizabeth M Kanny 《The American journal of occupational therapy》2005,59(4):467-474
PURPOSE: To provide a model for assessing occupational therapy workforce needs by using a demand-based approach to determine current workforce status in the Northwest region. Regional information may have implications for addressing national occupational therapy service needs. METHOD: A questionnaire was sent to a proportional random sample of 234 facilities that hire occupational therapy practitioners. Data were collected in July-August 2003 using structured mailing and follow-up procedures. RESULTS: Response rate was 79%. Twenty-four percent reported occupational therapy vacancies and 11% occupational therapy assistant vacancies; 48% predicted an increase in occupational therapy positions in the next 2 years and 41% an increase in occupational therapy assistant positions. Sixty-three percent of respondents reported difficulty in hiring. DISCUSSION: This study identifies an occupational therapy workforce shortage in the Northwest. Management of a shortage is critical, for even short-term adjustments could lead to permanent changes in service provision. This study demonstrates the importance of current information on the status of the national workforce and serves as a model for future studies. 相似文献
997.
998.
999.
J Hartung K D Kalache C Heyna K-S Heling M Kuhlig R Wauer R Bollmann R Chaoui 《Ultrasound in obstetrics & gynecology》2005,25(6):566-572
OBJECTIVE: To describe the course and outcome of fetuses with absent or reversed end-diastolic (ARED) flow in the umbilical artery (UA) and to examine the influence of prematurity according to gestational age at delivery. METHODS: Sixty pregnancies complicated by ARED flow in the UA were monitored by repeat Doppler measurements of arterial and venous vessels, non-stress tests (cardiotocogram (CTG)) and maternal investigations, and were delivered between 24 and 34 weeks. Fetal outcome was investigated and compared to a control group of appropriate-for-gestational age (AGA) preterm neonates, matched for gestational age. Mortality, birth weight, Apgar scores, postnatal cord arterial pH and need for ventilation were all recorded, as were cases of respiratory distress syndrome, bronchopulmonary dysplasia, persistent ductus arteriosus, necrotizing enterocolitis, intraventricular hemorrhage, periventricular leukomalacia, abnormal neurological findings and those requiring surgical intervention. Additionally, the group of fetuses with ARED flow was divided into three subgroups of different degrees of prematurity (delivery between 24 + 0 and 28 + 6 weeks, delivery between 29 + 0 and 31 + 6 weeks, and delivery after 32 weeks) and compared according to the above parameters. RESULTS: Pre- or postnatal death occurred in 16 cases. Comparing the 44 (61%) that were born alive with the AGA neonates, significant differences were found in birth weight (P < 0.001), arterial pH value (P < 0.001), bronchopulmonary dysplasia (P = 0.002) and intestinal complications (P < 0.01). Prematurity-related complications were: need for ventilation (P = 0.001), respiratory distress syndrome (P < 0.0001), periventricular leukomalacia (P = 0.002) and pathological neurological testing (P = 0.005). CONCLUSIONS: Neonates displaying ARED flow before birth are growth restricted, acidemic at delivery and are at high risk of developing bronchopulmonary dysplasia and intestinal complications. While perinatal mortality seems to be related to abnormal fetal Doppler velocimetry, age at delivery has a significant impact on short-term morbidity. After 32 weeks, morbidity is low and delivery should be considered. It could be speculated from our data that prolongation of pregnancy with Doppler velocimetry monitoring could help to reduce morbidity, although prolongation remains limited in most cases. 相似文献
1000.