全文获取类型
收费全文 | 2844篇 |
免费 | 218篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 175篇 |
妇产科学 | 56篇 |
基础医学 | 291篇 |
口腔科学 | 58篇 |
临床医学 | 337篇 |
内科学 | 558篇 |
皮肤病学 | 35篇 |
神经病学 | 161篇 |
特种医学 | 371篇 |
外科学 | 383篇 |
综合类 | 67篇 |
一般理论 | 2篇 |
预防医学 | 200篇 |
眼科学 | 40篇 |
药学 | 151篇 |
中国医学 | 1篇 |
肿瘤学 | 119篇 |
出版年
2022年 | 30篇 |
2021年 | 49篇 |
2020年 | 30篇 |
2019年 | 45篇 |
2018年 | 56篇 |
2017年 | 40篇 |
2016年 | 44篇 |
2015年 | 38篇 |
2014年 | 65篇 |
2013年 | 99篇 |
2012年 | 100篇 |
2011年 | 110篇 |
2010年 | 75篇 |
2009年 | 84篇 |
2008年 | 103篇 |
2007年 | 91篇 |
2006年 | 99篇 |
2005年 | 102篇 |
2004年 | 92篇 |
2003年 | 84篇 |
2002年 | 97篇 |
2001年 | 85篇 |
2000年 | 75篇 |
1999年 | 62篇 |
1998年 | 68篇 |
1997年 | 64篇 |
1996年 | 55篇 |
1995年 | 52篇 |
1994年 | 45篇 |
1993年 | 47篇 |
1992年 | 65篇 |
1991年 | 68篇 |
1990年 | 68篇 |
1989年 | 84篇 |
1988年 | 72篇 |
1987年 | 53篇 |
1986年 | 54篇 |
1985年 | 59篇 |
1984年 | 49篇 |
1983年 | 42篇 |
1982年 | 41篇 |
1981年 | 25篇 |
1980年 | 31篇 |
1979年 | 33篇 |
1978年 | 29篇 |
1977年 | 21篇 |
1976年 | 17篇 |
1975年 | 21篇 |
1974年 | 22篇 |
1970年 | 18篇 |
排序方式: 共有3085条查询结果,搜索用时 15 毫秒
1.
A McRae S Hjorth D W Mason L Dillon T R Tice 《Journal of neural transplantation & plasticity》1991,2(3-4):165-173
Biodegradable controlled-release microsphere systems made with the biocompatible biodegradable polyester excipient poly [DL lactide-co-glycolide] constitute an exciting new technology for drug delivery to the central nervous system (CNS). The present study describes functional observations indicating that implantation of dopamine (DA) microspheres encapsulated within two different polymer excipients into denervated-striatal tissue assures a prolonged release of the transmitter in vivo. Moreover, in this regard, the results show that there were clear cut temporal differences in the effect of the two DA microsphere formulations compared in this study, probably reflecting variations in the actual composition (i.e., lactide to glycolide ratio) of the two copolymer excipients examined. This technology has considerable potential for basic research with possible clinical application. 相似文献
2.
表小檗碱对α受体的作用 总被引:2,自引:0,他引:2
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择 相似文献
3.
J R Blackman S Dillon 《The Journal of the American Board of Family Practice / American Board of Family Practice》1992,5(4):399-405
BACKGROUND: Venomous snakebites continue to cause great morbidity, and treatment options are confusing the attending physician. In the United States approximately 45,000 snakebites occur each year, of which some 8000 are by 20 species of venomous snakes. METHODS: Information on venomous snakes and snakebite treatment was gathered from the libraries of the Wilderness Medical Society and the Rocky Mountain Center for Wilderness Medicine in Boise, Idaho (co-supported by the Boise State University and the Family Practice Residency of Idaho), as well as from current literature files of physicians practicing wilderness medicine. RESULTS AND CONCLUSIONS: Three genera of venomous snakes account for the majority of poisonous snake envenomations in this country. Most hospitalized victims are bitten either by rattlesnakes or copperheads or by unidentified snakes. Most of these bites occur during the summer months and are found on the extremities. Field treatment focuses on the application of a vacuum extractor and transportation to the nearest medical facility. Although constriction band use can be helpful, tourniquets, incision and suction, and ice therapy are contraindicated. Electric shock therapy is of no use and could cause serious injury. Hospital management focuses on rapid clinical evaluation and laboratory tests to establish the degree of envenomation, looking for clotting abnormalities. If envenomation has occurred and is reactive, polyvalent antivenin should be administered according to the degree of envenomation. Errors in diagnosis and treatment result in increased morbidity and put attending physicians at risk for litigation. Prevention remains the most successful approach to snakebite management. 相似文献
4.
5.
Paul P. Dillon Stephen J. Daly John G. Browne Bernadette M. Manning Elma Loomans Aart Van Amerongen Richard O'Kennedy 《Food and Agricultural Immunology》2003,15(3):225-234
Public concern surrounding antibiotic contamination in food and food products has made it imperative to develop analytical methods for their detection. Polyclonal antibodies were used in the development of a surface plasmon resonance (SPR)-based inhibition immunoassay for cephalexin. A conjugate consisting of cephalexin-bovine serum albumin (BSA) was immobilized on the dextran gel surface of the sensor chip. Binding/regeneration studies of antibody to immobilized cephalexin were studied and dissociation of the antibody from the immobilized cephalexin was easily achieved with 10 mmol l-1 NaOH. Forty surface regeneration cycles were carried out and found to be reproducible with only a 7.4% decrease in binding over this number of regenerations. Model inhibition immunoassays for cephalexin were developed in PBS and spiked milk samples with detection ranges of 4.88 to 2,500 ng ml-1 and 244 to 3,906 pg ml-1, respectively. 相似文献
6.
F J Beek M S van Leeuwen N M Bax E H Dillon T D Witkamp A P van Gils 《AJNR. American journal of neuroradiology》1994,15(3):445
PURPOSETo determine whether the lumbosacral junction of the vertebral column can be identified with sonography in newborns and infants and thus serve as a method for counting the lumbar and sacral vertebral bodies.METHODSIn 32 newborns and infants, the number of ossified vertebral bodies distal to the lumbosacral junction was counted with sonography and radiography.RESULTSSonographic and radiographic findings agreed in 29 of 32 examinations (91%).CONCLUSIONSThe lordotic transition at the lumbosacral junction can be identified with sonography in the majority of newborns and infants, allowing intraspinal structures to be related to a specific vertebral level. 相似文献
7.
The neck 总被引:1,自引:0,他引:1
This article describes the clinical and imaging roles of MR with respect to the following: neck masses of known or uncertain etiology; staging of cervical metastatic disease; thyroid and parathyroid; and evaluation of the thoracic inlet. Pertinent normal anatomy is highlighted when appropriate. 相似文献
8.
G. Michael Taylor Thomas J. Neuhaus Vanita Shah Susannah Dillon T. Martin Barratt 《Pediatric nephrology (Berlin, Germany)》1997,11(4):404-410
Experimental studies have pointed to charge selectivity as an important determinant of glomerular permeability to macromolecules.
Loss of glomerular basement membrane (GBM) polyanion has been proposed as a cause of the selective proteinuria in minimal
change nephrotic syndrome (MCNS). However, the presence of less-anionic albumin in urine than plasma from MCNS and focal and
segmental glomerulosclerosis (FSGS) patients has been interpreted both as evidence for partial maintenance of charge selectivity
and for involvement of other pathogenic mechanisms. The exact role of charge selectivity in the pathogenesis of nephrotic
proteinuria remains controversial. We have examined the clearance of endogenous proteins of differing size and charge in children
with idiopathic nephrotic syndrome (NS). Chromatofocusing was used to determine the isoelectric points (pIs) of albumins in
paired plasma and urine samples from patients with FSGS (n = 6) and MCNS (n = 6). Charge selectivity was assessed by comparing the pIs of the fractions with the highest albumin concentration (modal
pI) in plasma and urine. The difference between the modal pIs was defined as the delta modal pI. Charge selectivity was also
assessed from the albumin/transferrin and IgG4/IgG1 clearance ratios; size selectivity from the IgG1/albumin and IgG1/transferrin
as well as the IgG4/albumin and IgG4/transferrin clearances. In children with FSGS, the mean (± SD) delta modal pI was – 0.05
± 0.16, and in MCNS – 0.05 ± 0.11. Neither value differed significantly from zero. The albumin/transferrin clearance ratio
showed no significant difference between FSGS and MCNS, but the IgG4/IgG1 clearance ratio was significantly higher in MCNS
(P<0.05). Size selectivity was significantly reduced in FSGS compared with MCNS (for IgG1/transferrin P<0.01 and for IgG1/albumin P<0.05). For IgG4/transferrin and IgG4/albumin, P was <0.05. In conclusion, there was no evidence for residual charge selectivity in idiopathic NS associated with either MCNS
or FSGS during nephrotic-range proteinuria. There was a significant loss of GBM size selectivity in children with FSGS with
heavy proteinuria compared with children with MCNS with heavy proteinuria.
Received August 7, 1996; received in revised form and accepted December 16, 1996 相似文献
9.
10.
Evaluation of the offer vs. serve option within self-serve, choice menu lunch program at the elementary school level 总被引:1,自引:0,他引:1
The feasibility of a centralized menu and the effectiveness of an "offer vs. serve" option within a self-serve, choice menu lunch program at the elementary school level were determined. Student trays (no. = 370/day) were visually evaluated for foods chosen and consumed. The same 1-week menu was served at two urban Southern schools. One represented a high-poverty-area, all-black-student school and the other represented a middle-income-area school with a white to black student ratio of 3:1. Students were able to choose the required USDA minimal number of three foods, and 66% of the foods selected were similar at the two schools, demonstrating that a centralized menu was feasible. Three-fourths of the students were able to choose more than 75% of one-third of the RDA for all nutrients except pyridoxine and ascorbic acid at both schools and iron at the high-poverty school. Twenty-five percent or more of the students did not consume 75% of one-third the Recommended Dietary Allowance for thiamin, vitamin B-6, ascorbic acid, iron, and magnesium at either school or of niacin and vitamin A at the middle-income school. Overall plate waste was 12.9%, with younger children wasting more food than older children and more waste in the middle-income than the high-poverty school. In general, the "offer vs. serve" was an effective option. 相似文献