全文获取类型
收费全文 | 2470391篇 |
免费 | 176099篇 |
国内免费 | 3637篇 |
专业分类
耳鼻咽喉 | 33629篇 |
儿科学 | 79049篇 |
妇产科学 | 65595篇 |
基础医学 | 365569篇 |
口腔科学 | 68124篇 |
临床医学 | 218757篇 |
内科学 | 482675篇 |
皮肤病学 | 55024篇 |
神经病学 | 195159篇 |
特种医学 | 90842篇 |
外国民族医学 | 492篇 |
外科学 | 366821篇 |
综合类 | 48088篇 |
现状与发展 | 12篇 |
一般理论 | 873篇 |
预防医学 | 198082篇 |
眼科学 | 57698篇 |
药学 | 184622篇 |
11篇 | |
中国医学 | 5012篇 |
肿瘤学 | 133993篇 |
出版年
2021年 | 20948篇 |
2019年 | 21797篇 |
2018年 | 30926篇 |
2017年 | 22820篇 |
2016年 | 25142篇 |
2015年 | 28292篇 |
2014年 | 39064篇 |
2013年 | 58477篇 |
2012年 | 82680篇 |
2011年 | 87791篇 |
2010年 | 51182篇 |
2009年 | 47545篇 |
2008年 | 81258篇 |
2007年 | 86662篇 |
2006年 | 87118篇 |
2005年 | 84213篇 |
2004年 | 80305篇 |
2003年 | 77095篇 |
2002年 | 74549篇 |
2001年 | 111102篇 |
2000年 | 114041篇 |
1999年 | 95521篇 |
1998年 | 27438篇 |
1997年 | 23947篇 |
1996年 | 24335篇 |
1995年 | 22963篇 |
1994年 | 21108篇 |
1993年 | 19884篇 |
1992年 | 73257篇 |
1991年 | 71246篇 |
1990年 | 69605篇 |
1989年 | 66746篇 |
1988年 | 61362篇 |
1987年 | 60121篇 |
1986年 | 56234篇 |
1985年 | 53969篇 |
1984年 | 40031篇 |
1983年 | 34042篇 |
1982年 | 20201篇 |
1979年 | 36795篇 |
1978年 | 26264篇 |
1977年 | 21820篇 |
1976年 | 20918篇 |
1975年 | 22491篇 |
1974年 | 26999篇 |
1973年 | 25714篇 |
1972年 | 24068篇 |
1971年 | 22893篇 |
1970年 | 21060篇 |
1969年 | 20177篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
To produce hybrids, one member of the parental line is genetically made male-sterile. This male-sterile trait is encoded by mitochondria so that it is maternally inherited. Consequently, the progeny of a male-sterile plant is fully sterile. Nevertheless, during the handling of cytoplasmic male-sterile seed stocks, some mixture with seeds of the maintainer lines can occur. Up to the present time, the only way to check the homogeneity of the cytoplasmic male-sterile seed stock was to grow the plants until flowering time. We have developed a method which can be used immediately after the harvest, allowing us to check samples from both sunflower and sugar beet. We used the mitochondrial plasmid, present only in the maintainer lines, as a probe for the total nucleic acids prepared from the cytoplasmic male-sterile seed stocks which might be contaminated. The signals compared to those of samples artificially contaminated allow us to measure as few as one male-fertile seed in 1000 seeds in a rapid and accurate manner. 相似文献
992.
Boom F. A. Van der Heijden Van Beek M. A. E. Paalman A. C. A. Stout-Zonneveld A. 《International journal of clinical pharmacy》1991,13(3):130-136
International Journal of Clinical Pharmacy - In order to calculate the minimum sterilization process conditions to obtain the generally accepted sterility level (less than 1·10?6... 相似文献
993.
D Puluszézak A Bianchi J C Cazin M Cazin 《Methods and findings in experimental and clinical pharmacology》1991,13(6):419-425
A detailed examination of quantitative relationships of pharmacological action with plasma and tissue concentrations of indomethacin has been undertaken in the rat, after single oral administration of two sustained release preparations. In this study, drug was assayed by high performance liquid chromatography, whereas antiinflammatory response was assessed through the carrageenin-induced edema test. Significant linear correlations (p less than 0.001) were found between logarithmically transformed percent inhibition of edema and logarithmically transformed plasma, as well as tissue levels of indomethacin. However, the lack of significance for partial correlation regarding tissue concentration, contrary to plasma concentration, suggests that pharmacological response is more closely related to the latter, indicating that antidematous effect is mediated via the circulating drug rather than a local action in target tissues. This assumption is further discussed from the equivalence point of view. The relevance of this type of study in the case of topical administration of indomethacin is addressed as well. Taking into account the predictive value of the rat paw edema test for clinical efficacy, relationships similar to those observed are to be expected in man. The high correlation existing between plasma concentration of indomethacin and its pharmacological effect justifies the development and use of sustained release preparations in order to improve the outcome of treatment with this nonsteroidal antiinflammatory drug. 相似文献
994.
The contributors propose a set of newly performed hygienic studies in the widely developed technologies of electrotype, expound a complex of the hazardous occupational factors commonly encountered in modern galvanoplastics, contamination of the equipment, overalls and the skin with the metallic compounds contained in the galvanic electrolytes. Shops with non-isolated electrotype lines were characterized by the most unfavourable labour conditions. 相似文献
995.
996.
997.
Effect of a natural flavonoid on gastric mucosal barrier 总被引:2,自引:0,他引:2
The effects of 3,5,7-trihydroxy-2-(3,4-dihydroxyphenyl)-1-benzopyrylium chloride (IdB 1027) on the rat gastric mucosa were evaluated. IdB 1027 administered intragastrically at doses ranging from 100 to 400 mg/kg inhibited the fall in transmucosal potential difference and the increase in H+ back-diffusion induced by acetylsalicylic acid. Moreover, IdB 1027 at doses of 50 and 200 mg/kg by intragastric route increased the gastric bicarbonate secretion. These results suggest that the gastroprotective activity of IdB 1027 is mediated by an increase in the efficiency of gastric mucosal barrier. 相似文献
998.
999.
Mycobacterium ulcerans infection in Ashanti region, Ghana 总被引:1,自引:0,他引:1
T S van der Werf W T van der Graaf D G Groothuis A J Knell 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1989,83(3):410-413
We describe a series of 96 cases of Mycobacterium ulcerans infection (Buruli ulcer) from a new endemic focus in the Afram valley, north of Agogo, in Ghana. 63 cases were children under 13 years old. Active treatment by excision and skin grafting necessitates long stays in hospital and repeated procedures. Scarring and contracture are frequent. Eyes and other vital organs may be destroyed. In its endemic foci Buruli ulcer is a serious health burden on rural populations. Research is urgently needed, especially in prevention and non-surgical management. 相似文献
1000.
Diabetic polyneuropathy 总被引:1,自引:0,他引:1