全文获取类型
收费全文 | 764268篇 |
免费 | 52977篇 |
国内免费 | 1443篇 |
专业分类
耳鼻咽喉 | 9943篇 |
儿科学 | 24852篇 |
妇产科学 | 19081篇 |
基础医学 | 119955篇 |
口腔科学 | 21524篇 |
临床医学 | 69371篇 |
内科学 | 145959篇 |
皮肤病学 | 17035篇 |
神经病学 | 54947篇 |
特种医学 | 28232篇 |
外国民族医学 | 116篇 |
外科学 | 111952篇 |
综合类 | 15322篇 |
现状与发展 | 2篇 |
一般理论 | 237篇 |
预防医学 | 56018篇 |
眼科学 | 17395篇 |
药学 | 58133篇 |
3篇 | |
中国医学 | 2504篇 |
肿瘤学 | 46107篇 |
出版年
2021年 | 6380篇 |
2019年 | 6286篇 |
2018年 | 8890篇 |
2017年 | 6820篇 |
2016年 | 7660篇 |
2015年 | 8550篇 |
2014年 | 11511篇 |
2013年 | 17526篇 |
2012年 | 23244篇 |
2011年 | 24353篇 |
2010年 | 14755篇 |
2009年 | 13671篇 |
2008年 | 22571篇 |
2007年 | 24234篇 |
2006年 | 24587篇 |
2005年 | 23005篇 |
2004年 | 22606篇 |
2003年 | 21318篇 |
2002年 | 20910篇 |
2001年 | 38178篇 |
2000年 | 38777篇 |
1999年 | 32118篇 |
1998年 | 8678篇 |
1997年 | 7334篇 |
1996年 | 7559篇 |
1995年 | 7243篇 |
1994年 | 6597篇 |
1993年 | 6148篇 |
1992年 | 24291篇 |
1991年 | 24181篇 |
1990年 | 23517篇 |
1989年 | 23259篇 |
1988年 | 21053篇 |
1987年 | 20426篇 |
1986年 | 19414篇 |
1985年 | 18178篇 |
1984年 | 13332篇 |
1983年 | 11333篇 |
1982年 | 6348篇 |
1979年 | 12115篇 |
1978年 | 8474篇 |
1977年 | 7158篇 |
1976年 | 6872篇 |
1975年 | 7617篇 |
1974年 | 8886篇 |
1973年 | 8475篇 |
1972年 | 7980篇 |
1971年 | 7409篇 |
1970年 | 7117篇 |
1969年 | 6518篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
171.
N Nelson O Finnstr?m L Larsson 《Scandinavian journal of clinical and laboratory investigation》1987,47(2):111-117
Thirty-one full-term newborn babies were investigated in order to establish reference values for ionized calcium. Only children fulfilling certain optimality criteria (with best possible maternal and infant conditions and uncomplicated pregnancy and delivery) were included. All infants were breast fed. Capillary blood for analysis of ionized calcium was collected by heel puncture on day 1 (6-36 h post partum, p.p.), day 3 (60-84 h p.p.) and day 5 (108-132 h p.p.). Ionized calcium was measured with a semi-automatic electrode system ICA 1 (Radiometer A/S, Copenhagen, Denmark). The reference ranges (mean +/- 2 SD) for days 1, 3 and 5 were 1.05-1.37, 1.10-1.42 and 1.20-1.48 mmol/l, respectively. The mean ionized calcium concentration on day 1 was significantly lower than on days 3 and 5. Reference values are also given for total calcium, magnesium and phosphate. We emphasize that it is impossible to calculate ionized calcium from total calcium or vice versa. 相似文献
172.
Ohne Zusammenfassung 相似文献
173.
E J Buchmann R C Pattinson N Nyathikazi 《Suid-Afrikaanse tydskrif vir geneeskunde》2002,92(11):897-901
BACKGROUND: The recent amalgamation of data by users of the Perinatal Problem Identification Programme (PPIP) throughout South Africa has culminated in the publication of the Saving Babies report. OBJECTIVES: To determine the absolute rate of death from intrapartum-related birth asphyxia, and the contribution of intrapartum-related asphyxia to total perinatal mortality in South African hospitals, and to identify the primary obstetric causes and avoidable factors for these deaths. METHODS: The amalgamated PPIP data for the year 2000 were obtained from 27 state hospitals (6 metropolitan, 12 town and 9 rural) in South Africa. In PPIP-based audit, all perinatal deaths are assigned primary obstetric causes and avoidable factors, and these elements were obtained for all deaths resulting from intrapartum-related birth asphyxia. RESULTS: There were 123,508 births in the hospitals surveyed, with 4,142 perinatal deaths among infants > or = 1,000 g, giving a perinatal mortality rate of 33.5/1,000 births. The perinatal mortality rate from intrapartum-related birth asphyxia was 4.8/1,000 births. The most frequent avoidable factors were delay by mothers in seeking attention during labour (36.6%), signs of fetal distress interpreted incorrectly (24.9%), inadequate fetal monitoring (18.0%) and no response to poor progress in labour (7.0%). The perinatal mortality rates for metropolitan, town, and rural areas were 30.0, 39.4 and 30.9/1,000 births respectively. The contribution of intrapartum-related birth asphyxia to perinatal mortality in these areas was 10.8%, 16.7% and 26.4% respectively. CONCLUSION: The high rates of perinatal death from intrapartum-related birth asphyxia in South Africa are typical of those in underdeveloped countries, with the most serious deficiencies in rural areas. Most of these deaths are avoidable and the reduction of these rates presents an important challenge to providers of perinatal care in this country. Areas worthy of research and action include provision of mothers' waiting facilities in rural regions, improvements in fetal monitoring, partogram-based labour management, and the establishment of midwifery staffing norms for South African labour units. 相似文献
174.
175.
N Deb-Joardar N Germain G Thuret A -F Garcin P Manoli A Defreyn P Gain B Estour 《Diabetic medicine》2007,24(3):303-307
AIMS: Screening for diabetic retinopathy (DR) is highly inadequate in France because of insufficient infrastructure and increasing disease prevalence. We describe the results of the first systematic DR screening programme established in a university diabetes department. METHODS: In this cross-sectional study conducted over 1 year, consecutive adult patients underwent three-field retinal photography with the Topcon TRC NW6S digital fundus camera following pupillary dilatation with Tropicamide 1%. A questionnaire provided information on patients' systemic and ocular history. Glycated haemoglobin (HbA1c) was measured at the screening visit.Two ophthalmologists graded the retinal photographs in a masked fashion. RESULTS: Of 1157 patients attending the diabetes department, 1153 (99.7%)underwent photographic screening. Images were gradable in 96% patients.Diabetic retinopathy was detected in 522 (45%) patients and sight-threatening DR in 167 (14%). Of 704 (61%) patients previously believed to have no DR,254 (34%) screened positive. The presence of DR was associated with age,insulin use and non-Caucasian ethnicity in Type 2 patients, and with duration of diabetes and HbA1c in Type 1 and Type 2 patients. Associated ocular pathologies were diagnosed in 612 (53%) patients. CONCLUSIONS: Our photographic screening programme using pharmacological mydriasis provided a high screening coverage feasible in a hospital setting. We obtained information regarding prevalence and associated risk factors of DR inpatients attending a tertiary care centre. Screening was well accepted by patients and met with no protest from city ophthalmologists. It generated considerable interest among endocrinologists and feedback of results is expected to improve optimization of glycaemic control. 相似文献
176.
The β‐adhesin part of the Porphyromonas gingivalis W50 (ATCC 53978) protease HRgpA was cloned in an eukaryotic expression vector and expressed in COS‐7 cells. The monoclonal antibody MAb (61BG1.3), specific for the hemagglutinating domain of β‐adhesin, recognized the expressed β‐adhesin in the transfected cells both by immunoblot and immunofluorescence. Sprague Dawley rats were immunized intramuscularly with β‐adhesin encoding expression plasmid and expression plasmid without β‐adhesin insert. Skeletal muscle tissue at the site of immunization in the β‐adhesin immunized animals was shown to express this protein. The immunization induced a β‐adhesin‐specific antibody response. Sera from the immunized animals were tested for hemagglutination inhibiting activity. Due to high natural inhibiting activity in all rat sera tested, no increased hemagglutination inhibition was detected in sera from the β‐adhesin immunized animals. 相似文献
177.
178.
179.
180.
G K Hulse V Stalenberg D McCallum W Smit G O'neil N Morris R J Tait 《Journal of controlled release》2005,108(1):43-55
In order to assess the histological tissue changes over time around the site of implant, tissue biopsies were taken at 1 to 38 months post-implant from 54 (34 male) consenting human subjects who had received the Australian subcutaneous naltrexone-poly(DL-lactide) implant for heroin dependence. The implant consists of multiple tablets containing compressed naltrexone-poly[trans-3,6-dimethyl-1,4-dioxane-2,5-dione] (DL-lactide) loaded microspheres. Assessment of tissue samples by pathologists showed an early phase (up to 12 months post-implant) of inflammation, foreign body reaction, and fibrosis. This subsided gradually over the next 12 months until tissue returned to normal by 25+ months. Sufficient evidence was not available to conclude that the poly(DL-lactide) implant matrix was totally biodegradable within the study period. While implant material was not identified in most of the latter biopsies, its presence was noted in one biopsy at 26 months post-implant. Nevertheless the study results did demonstrate the implant's biocompatibility by the lack of inflammation, foreign body reaction, and fibrosis detected by 25+ months. It seems highly probable that surgical technique rather than the implant itself was associated with the additional finding of fat necrosis. Moderate fat necrosis was observed as a common feature of biopsies carried out during the first 6 months following implant. It subsided to mild levels over the next 18 months, and was notably absent by 25+ months. The results of the study indicated that the Australian naltrexone-poly(DL-lactide) implant is well tolerated and may have a role for use in the management of medical conditions such as heroin dependence. 相似文献