全文获取类型
收费全文 | 2289025篇 |
免费 | 170975篇 |
国内免费 | 3359篇 |
专业分类
耳鼻咽喉 | 31652篇 |
儿科学 | 75730篇 |
妇产科学 | 65887篇 |
基础医学 | 337138篇 |
口腔科学 | 64582篇 |
临床医学 | 205688篇 |
内科学 | 445028篇 |
皮肤病学 | 48582篇 |
神经病学 | 181881篇 |
特种医学 | 87303篇 |
外国民族医学 | 602篇 |
外科学 | 339408篇 |
综合类 | 48348篇 |
现状与发展 | 4篇 |
一般理论 | 828篇 |
预防医学 | 180725篇 |
眼科学 | 52348篇 |
药学 | 171624篇 |
7篇 | |
中国医学 | 4093篇 |
肿瘤学 | 121901篇 |
出版年
2018年 | 22865篇 |
2016年 | 19238篇 |
2015年 | 22354篇 |
2014年 | 30864篇 |
2013年 | 47183篇 |
2012年 | 64481篇 |
2011年 | 68871篇 |
2010年 | 40295篇 |
2009年 | 38424篇 |
2008年 | 65776篇 |
2007年 | 70826篇 |
2006年 | 71181篇 |
2005年 | 69763篇 |
2004年 | 67158篇 |
2003年 | 64538篇 |
2002年 | 63215篇 |
2001年 | 100201篇 |
2000年 | 102630篇 |
1999年 | 86980篇 |
1998年 | 25055篇 |
1997年 | 22488篇 |
1996年 | 22928篇 |
1995年 | 21768篇 |
1994年 | 20497篇 |
1993年 | 19011篇 |
1992年 | 70077篇 |
1991年 | 69123篇 |
1990年 | 67845篇 |
1989年 | 65726篇 |
1988年 | 61253篇 |
1987年 | 60136篇 |
1986年 | 57364篇 |
1985年 | 54580篇 |
1984年 | 41148篇 |
1983年 | 35859篇 |
1982年 | 21461篇 |
1981年 | 19323篇 |
1979年 | 39485篇 |
1978年 | 28368篇 |
1977年 | 24089篇 |
1976年 | 22591篇 |
1975年 | 24634篇 |
1974年 | 29465篇 |
1973年 | 28720篇 |
1972年 | 27230篇 |
1971年 | 25392篇 |
1970年 | 23801篇 |
1969年 | 22730篇 |
1968年 | 21305篇 |
1967年 | 18970篇 |
排序方式: 共有10000条查询结果,搜索用时 529 毫秒
991.
Tear mucus crystallization in children with cystic fibrosis 总被引:1,自引:0,他引:1
M Rolando F Baldi G Calabria 《Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift für Augenheilkunde》1988,197(4):202-206
Cystic fibrosis is characterized by an abnormally high electrolyte concentration in exocrine secretions. The authors performed the tear mucus ferning test in 26 eyes of children with cystic fibrosis and compared the results to those in an equal number of age-matched normals. The results suggest that the increased electrolyte concentration could be responsible for the increased hyperviscosity of mucus. The tear mucus ferning test appears to be a suitable diagnostic test for the assessment of cystic fibrosis. 相似文献
992.
Treatment versus no treatment in chronic open angle glaucoma 总被引:1,自引:0,他引:1
In a controlled randomized study 15 patients (20 eyes) with chronic open angle glaucoma and visual field defects were followed by greater than 1 year, 12 of them were followed for 3 years. Half of the group were untreated controls, the other half treated with pressure reducing medical therapy. At least 5 consecutive computerized visual fields were recorded (COMPETER) on each eye, and the linear regression coefficient was calculated. With the reservation for uncontrolled compliance no significant difference in the line of favourable effect of pressure reduction could be spotted, in spite of an average pressure reduction in the treated group of 4 mmHg. More important than this result, which is open to criticism for the smallness of the material, uncontrolled compliance etc, is the lesson that a randomized experiment with treated and non-treated glaucoma cases carried out in accordance with the Helsingfors convention is hardly feasible. 相似文献
993.
994.
S de Bustros J T Thompson R G Michels T A Rice B M Glaser 《The British journal of ophthalmology》1988,72(9):692-695
We used vitreous surgery to remove idiopathic epiretinal membranes from the macular area in 70 consecutive cases. The abnormal tissue was successfully removed in each case. Vision improved postoperatively in 61 eyes (87%), remained unchanged in six eyes (9%), and worsened in three eyes (4%). However, at the time of final examination vision was improved in only 47 eyes (67%), primarily because of the occurrence or progression of nuclear sclerosis, which occurred in 38 of 60 phakic eyes (63%). Four preoperative factors were associated with final visual acuity of 20/60 or better: (1) initial vision of 20/100 or better, (2) shorter preoperative duration of blurred vision, (3) thin epiretinal membrane, and (4) absence of traction retinal detachment. 相似文献
995.
996.
Of 7 plasmids we tested, the plasmid pORF2 was eliminated in vitro with the most efficiency by treatment with subinhibitory concentrations of novobiocin, coumermycin and 10 quinolones. It showed a cure rate of 43% by enoxacin; 12% by novobiocin, pefloxacin, ciprofloxacin and CI-934; 7% by coumermycin and ofloxacin; 9% by amifloxacin; and 4% by AM-833. On the other hand, pSC194, pBR322 and pMH612 were poorly cured in vitro by quinolones, except pSC194 which was cured 33% by enoxacin. R1, pP1603, and pUB110 were unaffected by the treatment. Mice were challenged intraperitoneally with a 2XLD50 of Escherichia coli carrying the ORF2 plasmid and were treated per os with 1 X or 1/2 X ED50 of either enoxacin or CI-934. The frequency of loss of ampicillin resistance determined 3 h after treatment shows curing effects of 92% for CI-934, 89% for enoxacin and 20% for untreated control. 相似文献
997.
998.
A G Antoshechkin L A Tatur VYuMaximova 《Clinica chimica acta; international journal of clinical chemistry》1988,177(3):239-244
In order to study metabolic distinctions in phenylketonuria, urinary metabolites in the form of trimethylsilyl derivatives have been characterized by high resolution gas chromatography and mass spectrometry. A previously unknown metabolite has been found in the urine of some untreated phenylketonuric infants between 2 and 5 yr of age. The metabolite was absent in healthy children of the same age. The metabolite appeared to be present in the urine of apparently healthy adults (25-32 yr old). The metabolite was identified as methoxyacetylcarbamide on the basis of mass fragmentation analysis and compared with synthetic methoxyacetylcarbamide. Their retention times and mass spectra coincided. 相似文献
999.
In this graphite-furnace atomic-absorption spectrometric method for measuring manganese in whole blood, we use a pyrolytic platform to minimize interference by sample matrix. For optimal sample ashing we denature the sample within the furnace with nitric acid and use oxygen as the purge gas at low temperatures. The mean manganese concentration found in blood from 15 unexposed city dwellers was 215 (2 SD 135) nmol/L. By comparison, the range of manganese concentrations in blood sampled from a group of Australian aborigines living near a surface manganese ore deposit on Groote Eylandt, Northern Territory, was much higher (median 405 nmol/L, range 175 to 990 nmol/L). 相似文献
1000.
J. E. BLUNDELL 《Nutrition Bulletin》1988,13(1):29-38
Do brain systems exist which control not only increases or decreases in food intake, but also bring about specific changes in the size and distribution of meals consumed, alter the selection of particular macronutrients and adjust feeding responses to the perceived pleasantness (hedonic value) of the food? A cautious yes can be given to each of these questions. Moreover, since most experimental work has been carried out on the brains of animals, we can also ask how well these animal data relate to the human condition; given the methodological issues involved in making such inferences, the answer is remarkably well. 相似文献