全文获取类型
收费全文 | 16630篇 |
免费 | 1082篇 |
国内免费 | 333篇 |
专业分类
耳鼻咽喉 | 52篇 |
儿科学 | 247篇 |
妇产科学 | 1817篇 |
基础医学 | 1414篇 |
口腔科学 | 298篇 |
临床医学 | 1712篇 |
内科学 | 1090篇 |
皮肤病学 | 141篇 |
神经病学 | 357篇 |
特种医学 | 163篇 |
外科学 | 1066篇 |
综合类 | 1416篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 1389篇 |
眼科学 | 160篇 |
药学 | 5788篇 |
21篇 | |
中国医学 | 451篇 |
肿瘤学 | 458篇 |
出版年
2024年 | 32篇 |
2023年 | 335篇 |
2022年 | 390篇 |
2021年 | 709篇 |
2020年 | 586篇 |
2019年 | 656篇 |
2018年 | 771篇 |
2017年 | 719篇 |
2016年 | 727篇 |
2015年 | 729篇 |
2014年 | 1050篇 |
2013年 | 2566篇 |
2012年 | 799篇 |
2011年 | 986篇 |
2010年 | 654篇 |
2009年 | 848篇 |
2008年 | 790篇 |
2007年 | 665篇 |
2006年 | 598篇 |
2005年 | 512篇 |
2004年 | 478篇 |
2003年 | 356篇 |
2002年 | 279篇 |
2001年 | 217篇 |
2000年 | 207篇 |
1999年 | 166篇 |
1998年 | 148篇 |
1997年 | 138篇 |
1996年 | 121篇 |
1995年 | 117篇 |
1994年 | 94篇 |
1993年 | 101篇 |
1992年 | 86篇 |
1991年 | 59篇 |
1990年 | 64篇 |
1989年 | 55篇 |
1988年 | 31篇 |
1987年 | 21篇 |
1986年 | 37篇 |
1985年 | 33篇 |
1984年 | 19篇 |
1983年 | 30篇 |
1982年 | 16篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
71.
ABSTRACT: Background: The percentage of United States’ births delivered by cesarean section has increased rapidly in recent years, even for women considered to be at low risk for a cesarean section. The purpose of this paper is to examine infant and neonatal mortality risks associated with primary cesarean section compared with vaginal delivery for singleton full‐term (37–41 weeks’ gestation) women with no indicated medical risks or complications. Methods: National linked birth and infant death data for the 1998–2001 birth cohorts (5,762,037 live births and 11,897 infant deaths) were analyzed to assess the risk of infant and neonatal mortality for women with no indicated risk by method of delivery and cause of death. Multivariable logistic regression was used to model neonatal survival probabilities as a function of delivery method, and sociodemographic and medical risk factors. Results: Neonatal mortality rates were higher among infants delivered by cesarean section (1.77 per 1,000 live births) than for those delivered vaginally (0.62). The magnitude of this difference was reduced only moderately on statistical adjustment for demographic and medical factors, and when deaths due to congenital malformations and events with Apgar scores less than 4 were excluded. The cesarean/vaginal mortality differential was widespread, and not confined to a few causes of death. Conclusions: Understanding the causes of these differentials is important, given the rapid growth in the number of primary cesareans without a reported medical indication. (BIRTH 33:3 September 2006) 相似文献
72.
腹腔镜辅助阴式子宫切除术与经腹子宫切除术的前瞻性随机对照研究 总被引:3,自引:0,他引:3
目的 比较评估腹腔镜辅助阴道子宫切除术与经腹子宫切除术两种手术的临床效果。方法 12 0例妇科良性疾病患者需行子宫切除术 ,但有经阴道子宫切除术的相对禁忌证、子宫不超过孕 16周 ,随机分成两组 ,甲组 (6 0例 )行腹腔镜辅助阴式子宫切除术 ,乙组 (6 0例 )行经腹子宫切除术。结果 两组患者年龄、产次、术前血红蛋白水平、子宫平均重量、术中失血、手术时间的差异无显著性 (P >0 .0 5 )。甲组术后疼痛程度、术后住院时间明显少于乙组 (P <0 .0 1) ,两组均未出现严重手术并发症。结论 腹腔镜辅助阴式子宫切除术具有创伤小、恢复快、住院时间短等优点 ,妇科医师经过良好的腹腔镜手术操作技能培训 ,能对大部分原不宜行阴式子宫切除术而需行经腹子宫切除术的患者行腹腔镜辅助阴式子宫切除术。 相似文献
73.
目的:探讨妊娠小于34周早产分娩方式的选择。方法:妊娠小于34周早产患者126例分为剖宫产组67例和阴道分娩组59例,比较不同分娩方式对分娩结局的影响。结果:孕28—30+6周时,阴道分娩组的新生儿死亡率明显高于剖宫产组(P〈0.05),其他两个孕周期间的两组新生儿死亡率比较无显著差异。阴道分娩组和剖宫产组的新生儿的死亡数随着出生体重的逐渐增加而不断减少,新生儿体重小于1500g时,两种分娩方式的死亡率之间比较存在显著性差异。结论:早产的主要原因是妊娠并发症,降低新生儿不良结局的根本措施还应延长孕龄,提高新生儿生存能力。 相似文献
74.
N. Blanchemain S. Haulon B. Martel M. Traisnel M. Morcellet H.F. Hildebrand 《European journal of vascular and endovascular surgery》2005,29(6):628-632
PURPOSE: Cyclodextrins (CDs) are torus shaped cyclic oligosaccharides with a hydrophobic internal cavity and a hydrophilic external surface. We performed and analysed an antibiotic binding on Dacron (polyethyleneterephtalate, PET) vascular grafts, previously coated with CDs based polymers. METHODS: The CDs coating process was based on the pad-dry-cure method patented in our laboratory. The Dacron prostheses were immersed into a solution containing a polycarboxylic acid, a cyclodextrin and a catalyst, and placed into a thermofixation oven before impregnation with an antibiotic solution (Vancomycin). Biocompatibility tests were performed with L132 human epithelial cells. The antibiotic release in an aqueous medium was assessed by batch type experiments using UV spectroscopy. RESULTS: Viability tests confirmed that the CDs polymers coating the Dacron fibers were not toxic towards L132 cell. Cell proliferation was similar on coated and uncoated grafts. A linear release of Vancomycin was observed over 50 days. CONCLUSION: Our results demonstrate the feasibility of coating CDs onto vascular Dacron grafts. Biological tests show no toxicity of the different cyclodextrins coated. A linear release of antibiotics was depicted over 50 days, demonstrating that cyclodextrin grafting was an efficient drug delivery system. 相似文献
75.
In order to evaluate the pump output control based on the oxygen delivery to peripheral tissues, arterial and mixed venous hemoglobin content ([Hb]) and oxygen saturation (SO2) were continuously monitored in three biventricular bypass animals (3-, 6-, and 40-day experiments) with fibrillating ventricles. The specially developed oxygen sensors were mounted in the outflow ports of the artificial hearts to measure [Hb] and SO2. One animal was exercised on the treadmill at 2.0 mile/h for 15 min with pump flows fixed to deliver oxygen of (a) above 13 cc/min/kg, (b) 10, and (c) 9. In (a), the mixed venous saturation (SvO2) dropped to approximately 25% with no increase in the blood lactate level. In (b) and (c), the SvO2 decreased to approximately 10-15% with increase in blood lactate levels from 4 to 10-30 mg/dl. Also, the recovery of the SvO2 in these groups following the termination of the exercise was slower in comparison to (a). The lower limit of the SvO2 level that would create oxygen debt situation in the peripheral tissues was approximately 25-30% for the exercise of 2.0 mile/h. The SvO2 reflects changes in respiratory status, pump output, hemoglobin level, and metabolism, and is thus a useful indicator to diagnose quickly the circulatory status as well as possibly to control the artificial heart output. 相似文献
76.
Wong Joseph Kuu Wei-Youh Burke Ronald Johnson Robert Wood Ray W. 《Pharmaceutical research》1995,12(1):144-148
The primary objective of this work was to establish a method to simulate the plasma levels of cilastatin, a model drug, following an intravenous in-line delivery scheme. In-vivo data in dogs obtained from this work were used to demonstrate the validity of the proposed approach. The in-line drug delivery system consists of a drug containing device which is placed between a large volume parenteral and a patient. Numerous advantages have been identified for this automatic in-line reconstitution delivery system. The numerical convolution integral algorithm was used in this work to perform plasma profile simulation. The results indicated that the simulated cilastatin plasma profile following in-line delivery closely agreed with the in-vivo data. 相似文献
77.
Colonic Drug Delivery: Enhanced Release of Indomethacin from Cross-Linked Chondroitin Matrix in Rat Cecal Content 总被引:4,自引:0,他引:4
Pharmaceutical Research - 相似文献
78.
为研究分娩方式是否影响新生儿免疫状态,检测和比较了68例妊娠足月阴道产和64例妊娠足月部宫产分娩的新生儿脐血C3、C4及IgG、IgA、IgM的含量,其结果:IgG的的含量阴产组明显高于剖宫产组,且男婴阴道产组IgG的信明显高于剖宫产。说明剖宫产可参降低新生儿免疫应签及抗感染能力。 相似文献
79.
Parental alcoholism and early child development 总被引:2,自引:0,他引:2
In a cohort of 532 pregnant women from the general population, it was found by compilation of the results from interviews, police records, hospital records and social welfare records that 23 mothers and 51 fathers in 64 families (12%) were suffering from alcoholism/heavy drinking. In these 64 families, the mother was an addict in only 13 families, both parents were addicts in 10 families, and in the remaining 41 families only the father was an addict. Pregnancy, delivery, the newborn child and the child's development until their fourth year of life have been described using a multidisciplinary approach and a longitudinal prospective design. An hypothesis on mental and physical development, and the occurrence of psychopathological symptoms in the children was tested. None of the children of the 13 alcoholic mothers was born with foetal alcohol syndrome, but foetal hazard was indicated by lower birth weight and a higher rate of perinatal deaths. Children of alcoholic parents had retarded mental development and showed more behavioural problems until 4 years of age than controls, but the differences related to physical development during the first year of life had then disappeared. Boys were found to be more vulnerable than girls. The consequences of behaviour seemed to be more pronounced when both parents were alcoholics. No obvious deviation was found when only the father was addicted. Regarding mental development, it appears that factors related to parental alcoholism, including genetic and social factors, and the sex of the child, are of greater importance than the neonatal score on reduced optimality. 相似文献
80.
S A Harvey P Ayabaca M Bucagu S Djibrina W N Edson S Gbangbade A McCaw-Binns B R Burkhalter 《International journal of gynaecology and obstetrics》2004,87(2):203-210
OBJECTIVES: Percentage of deliveries assisted by a skilled birth attendant (SBA) has become a proxy indicator for reducing maternal mortality in developing countries, but there is little data on SBA competence. Our objective was to evaluate the competence of health professionals who typically attend hospital and clinic-based births in Benin, Ecuador, Jamaica, and Rwanda. Methods: We measured competence against World Health Organization's (WHO) Integrated Management of Pregnancy and Childbirth guidelines. To evaluate knowledge, we used a 49-question multiple-choice test covering seven clinical areas. To evaluate skill, we had participants perform five different procedures on anatomical models. The 166 participants came from facilities at all levels of care in their respective countries. Results: On average, providers answered 55.8% of the knowledge questions correctly and performed 48.2% of the skills steps correctly. Scores differed somewhat by country, provider type, and subtopic. Conclusion: A wide gap exists between current evidence-based standards and current levels of provider competence. 相似文献