全文获取类型
收费全文 | 4275329篇 |
免费 | 350797篇 |
国内免费 | 15287篇 |
专业分类
耳鼻咽喉 | 60882篇 |
儿科学 | 132868篇 |
妇产科学 | 111699篇 |
基础医学 | 654505篇 |
口腔科学 | 118686篇 |
临床医学 | 387326篇 |
内科学 | 774717篇 |
皮肤病学 | 103188篇 |
神经病学 | 366114篇 |
特种医学 | 170483篇 |
外国民族医学 | 912篇 |
外科学 | 651468篇 |
综合类 | 126074篇 |
现状与发展 | 23篇 |
一般理论 | 2578篇 |
预防医学 | 361918篇 |
眼科学 | 100368篇 |
药学 | 301617篇 |
24篇 | |
中国医学 | 11354篇 |
肿瘤学 | 204609篇 |
出版年
2021年 | 55642篇 |
2020年 | 35453篇 |
2019年 | 58556篇 |
2018年 | 73121篇 |
2017年 | 55841篇 |
2016年 | 62150篇 |
2015年 | 75455篇 |
2014年 | 110174篇 |
2013年 | 175476篇 |
2012年 | 117153篇 |
2011年 | 120159篇 |
2010年 | 122723篇 |
2009年 | 125923篇 |
2008年 | 107394篇 |
2007年 | 113877篇 |
2006年 | 123427篇 |
2005年 | 118581篇 |
2004年 | 119539篇 |
2003年 | 110275篇 |
2002年 | 100905篇 |
2001年 | 154281篇 |
2000年 | 150436篇 |
1999年 | 139511篇 |
1998年 | 71251篇 |
1997年 | 67735篇 |
1996年 | 65620篇 |
1995年 | 61482篇 |
1994年 | 55561篇 |
1993年 | 51595篇 |
1992年 | 103555篇 |
1991年 | 98939篇 |
1990年 | 94043篇 |
1989年 | 91676篇 |
1988年 | 85298篇 |
1987年 | 83764篇 |
1986年 | 79457篇 |
1985年 | 77896篇 |
1984年 | 65934篇 |
1983年 | 58842篇 |
1982年 | 48127篇 |
1981年 | 44869篇 |
1980年 | 42162篇 |
1979年 | 57821篇 |
1978年 | 47027篇 |
1977年 | 41589篇 |
1976年 | 38650篇 |
1975年 | 37843篇 |
1974年 | 42413篇 |
1973年 | 40546篇 |
1972年 | 38014篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
C. -E. Jonsson 《European journal of plastic surgery》1993,16(3):143-148
Summary Malposition of the nasal bone, septum and the alar cartilage are striking features of the unilateral cleft nose deformity. An endonasal technique (the extramucosal) was used in 26 patients, aged 13–38 (median 19), to correct aesthetic and functional problems. Twenty-four patients were secondary and two were tertiary. The patients were followed from 1–9 years. The pathological anatomy of the septum varied considerably, so different types of septoplasties had to be done. In 20 patients, satisfactory aesthetic and functional results were obtained in one operation. Secondary corrections were indicated in six patients. In cases with no gross scarring in or around the alar cartilage, the form and position of this cartilage will be more normal once the alar cartilages have been undermined and the deviation of the nasal bone and the septum is corrected. 相似文献
922.
923.
T F Kruger J P Van der Merwe H J Odendaal F S Stander G M Grobler V A Hulme E L Erasmus K Coetzee M L Windt Y Swart 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,77(12):634-636
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate. 相似文献
924.
S.A. GEORGE D.J. BILSLAND N.J. WAINWRIGHT J. FERGUSON 《The British journal of dermatology》1993,128(3):301-305
Despite a widely held belief that the use of emollients prior to broad-band UVB irradiation accelerates clearance of psoriasis, only one single-blind controlled study exists in support of this. No similar study has been carried out with photochemotherapy (PUVA) or narrow-band UVB (311–313 nm) phototherapy. As some emollients absorb UV radiation, and thereby inhibit psoriasis clearance, there is a need to identify emollients suitable for pre-irradiation use. Coconut oil may be useful in this respect. In two randomized groups of patients with chronic plaque psoriasis undergoing either routine PUVA(n=14) or narrow-band UVB phototherapy (n=15), a single-blind controlled (half-body) study was undertaken to assess the died of pre-irradiation application of coconut oil. Patients were given PUVA twice weekly, or TL-01 therapy thrice weekly. The initial UV dose was 70% of previously determined minimal phototoxic (MPD) or minimal erythema doses (MED), with 40% incremental steps at each visit (reduced if adverse effects occurred). Psoriasis severity was scored on each side after every three treatments. No significant acceleration of psoriasis clearance was seen in either group. We do not, therefore, recommend the routine use of emollients prior to PUVA or TL-01 therapy when using near erythemogenic irradiation regimens. 相似文献
925.
The nature and extent of aggressive behaviour amongst people with learning difficulties (mental handicap) in a single health district 总被引:1,自引:0,他引:1
P. HARRIS 《Journal of intellectual disability research : JIDR》1993,37(3):221-242
ABSTRACT. This paper describes the method and results of a survey of aggressive behaviour amongst people with learning difficulties. The study was confined to a single health district in the South Western Region of the UK with a general population of about 370000. At the time of the survey, the Handicap Register for the district recorded 1362 people as having a learning difFiculty. The overall prevalence of aggressive behaviour amongst people with learning difficulties for whom base population data was available was 17.6%. The lowest rate was identified amongst day facilities (9.7 %) and the highest in hospitals within the district (38.2%). The prevalence rate amongst those attending schools for children with severe learning difSculties was 12.6%. Proportionately more males than females were reported to present problems of aggressive behaviour. The gender difference appeared to be largely accounted for by the disproportionate number of men identified within day facilities. There was no significant evidence of an association between the person's gender and the presence aggressive behaviour within schools or hospitals. The results indicated that, although physical and verbal aggression were the most frequently reponed behaviours, many of the sample were also said to engage in other forms of challenging behaviour, particularly self-injurious, ritualistic, stereotypical and withdrawn behaviour. The risk of a serious or very serious injury to another person was very low; 0.7% or six people with learning difiSculties firom the district were reponed to be currently presenting such a risk. Similarly, only 2% of the base population (n=18) were reponed to be extremely difficult to manage. The implications of the findings are discussed. 相似文献
926.
J Komen P J Van den Dobbelsteen W J Slierendrecht W B Van Muiswinkel 《Transplantation》1990,49(4):788-793
The fate of skin allografts exchanged among heterozygous and homozygous gynogenetic common carp siblings, and among newly developed inbred strains and F1 hybrids, is described. Heterozygous gynogenetic offspring were produced by fertilizing eggs with UV-irradiated sperm and by treating the resulting zygote with a cold shock (0 degree C, 45 min). The temperature shock causes retention of the second polar body, which allows the eggs to develop into normal diploid fry. Homozygous gynogenetic offspring were similarly produced by using a heat shock (40 degrees C, 2 min), which suppresses the first mitotic division. Skin allografts exchanged among heterozygous gynogenetic carp exhibited prolonged survival, with some allografts (21.8%) surviving for over 28 days. Furthermore, a strong histocompatibility locus was seen to segregate in this group. In contrast, skin allografts exchanged among homozygous gynogenetic siblings were all rejected within 14 days (MST 9.4 days). New homozygous inbred strains, designated JJ and MM, were produced by gynogenetic reproduction of homozygous female carps, while F1 hybrids were produced by crossing of these homozygous females with homozygous male siblings. All grafts exchanged among members of the same strain were permanently accepted. Likewise grafts from homozygous strain members were accepted by fish from the related F1-hybrids, while the reverse grafts were rejected. These results provide evidence for the idea that in the carp histocompatibility genes exist at least one major locus and multiple minor loci, which are codominantly expressed. 相似文献
927.
Summary This study explores the effects of a calcium-deficient diet on patterns of bone remodeling, and examines regional differences
in the amount of bone lost. Skeletally mature female rabbits (n=6) were fed a calcium-deficient diet (0.10% Ca2+ and 0.50% P) for 14 weeks. A separate group of rabbits (n=4) were fed a maintenance diet (1.2% Ca2+ and 0.45% P). Bone mineral content, serum calcium, and serum phosphorus were measured each week during the experimental period.
Following sacrifice, the L3 vetebra, femoral head, proximal tibial metaphysis, and tibial midshaft were analyzed histomorphometrically. Rabbits had 20%
less vertebral bone after only 14 weeks of a calcium-deficient diet. As in human postmenopausal osteoporosis, bone loss in
calcium-deficient rabbits occurs in the trabecular bone of the lumbar spine before that in the trabecular bone of the lower
extremity. Calcium-deficient diets alone do not lead to increased osteoid volume or thickness. Because bone loss is relatively
rapid and because the pattern of loss is similar in some respects to that found in humans, adult rabbits may provide an attractive
model of calcium deficiency osteoporosis in a skeletally mature mammal in which remodeling is predominant over modeling. 相似文献
928.
T. M. Skerry M.D. M.R.C.V.S. R. Suswillo A. J. El Haj N. N. Ali R. A. Dodds L. E. Lanyon 《Calcified tissue international》1990,46(5):318-326
Summary Previous studies of Alcian blue-induced birefringence in adult avian cortical bone showed that a short period of intermittent
loading rapidly produces an increased level of orientation of proteoglycans within the bone tissue. In the absence of further
loading, this persists for over 24 hours. We have proposed that this phenomenon could provide a means for “capturing” the
effects of transient strains, and so provide a persistent, constantly updated strain-related influence on osteocyte populations
related to the bones' averaged recent strain history, in effect, a “strain memory” in bone tissue. In our present study, we
use the Alcian blue-induced birefringence technique to demonstrate that proteoglycan orientation also occurs after intermittent
loading of both cortical and cancellous mammalian bonein vivo andin vitro. We also show that the change in birefringence is proportional to the magnitude of the applied strain, and that the reorientation
occurs rapidly, reaching a maximal value after only 50 loading cycles. Examination of electron micrographs of bone tissue
after staining with cupromeronic blue allows direct visualization and quantification of the change in proteoglycan orientation
produced by loading. This shows that intermittent loading is associated with a realignment of the proteoglycan protein cores,
bringing them some 5 degrees closer to the direction of collagen fibrils in the bone matrix. 相似文献
929.
John R. Jarrett M.D. 《Aesthetic plastic surgery》1990,14(1):87-92
Immediate reconstruction of more than 1000 breasts was performed on high-risk patients on whom a prophylactic mastectomy was done. The mastectomy removes as much breast tissue as possible while leaving sufficient skin, and possibly the nipple-areola complex, to enable immediate reconstruction. The creation of symmetrical, well-balanced muscle pockets for the implant is the most important factor in producing satisfactory results in these cases. 相似文献
930.
Bladder mucosa in urethral reconstructions 总被引:6,自引:0,他引:6