全文获取类型
收费全文 | 2688552篇 |
免费 | 204769篇 |
国内免费 | 8511篇 |
专业分类
耳鼻咽喉 | 34849篇 |
儿科学 | 88202篇 |
妇产科学 | 72953篇 |
基础医学 | 375176篇 |
口腔科学 | 76184篇 |
临床医学 | 243288篇 |
内科学 | 534772篇 |
皮肤病学 | 62522篇 |
神经病学 | 214130篇 |
特种医学 | 104926篇 |
外国民族医学 | 504篇 |
外科学 | 412764篇 |
综合类 | 63760篇 |
现状与发展 | 6篇 |
一般理论 | 903篇 |
预防医学 | 207804篇 |
眼科学 | 61458篇 |
药学 | 193403篇 |
11篇 | |
中国医学 | 5919篇 |
肿瘤学 | 148298篇 |
出版年
2018年 | 29312篇 |
2017年 | 22488篇 |
2016年 | 25598篇 |
2015年 | 29009篇 |
2014年 | 40451篇 |
2013年 | 60073篇 |
2012年 | 78865篇 |
2011年 | 83924篇 |
2010年 | 50898篇 |
2009年 | 48312篇 |
2008年 | 77966篇 |
2007年 | 83077篇 |
2006年 | 84349篇 |
2005年 | 81041篇 |
2004年 | 77925篇 |
2003年 | 74802篇 |
2002年 | 71671篇 |
2001年 | 134542篇 |
2000年 | 138142篇 |
1999年 | 114616篇 |
1998年 | 32193篇 |
1997年 | 28371篇 |
1996年 | 29114篇 |
1995年 | 28642篇 |
1994年 | 26497篇 |
1993年 | 24673篇 |
1992年 | 90631篇 |
1991年 | 87864篇 |
1990年 | 84720篇 |
1989年 | 81215篇 |
1988年 | 74619篇 |
1987年 | 73236篇 |
1986年 | 69010篇 |
1985年 | 65951篇 |
1984年 | 49463篇 |
1983年 | 41774篇 |
1982年 | 24744篇 |
1981年 | 22200篇 |
1980年 | 20558篇 |
1979年 | 43999篇 |
1978年 | 31150篇 |
1977年 | 26530篇 |
1976年 | 24568篇 |
1975年 | 25739篇 |
1974年 | 30674篇 |
1973年 | 29540篇 |
1972年 | 27445篇 |
1971年 | 25267篇 |
1970年 | 23321篇 |
1969年 | 21871篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Ileoanal reservoir for ulcerative colitis and familial polyposis 总被引:20,自引:0,他引:20
D J Schoetz J A Coller M C Veidenheimer 《Archives of surgery (Chicago, Ill. : 1960)》1986,121(4):404-409
Although total proctocolectomy with permanent ileostomy is regarded as the definitive therapy for ulcerative colitis and familial polyposis, psychologic and physical complications with this operation have stimulated the development of the operation of total abdominal colectomy, mucosal proctectomy, ileal reservoir, and ileoanal anastomosis as an alternative surgical procedure. Since 1980, 104 of these operative procedures have been completed with no operative mortality; experience has been gained with both the J- and S-type reservoirs. Despite an appreciable number of postoperative complications, satisfactory function of the reservoir has been achieved in 86 of 91 patients followed up for at least three months after closure of the ileostomy. The remaining five patients have required reinstitution of fecal diversion. Functional results have not differed between two-limbed and three-limbed reservoirs. This operation must be considered a viable alternative in patients with ulcerative colitis and familial polyposis. 相似文献
992.
993.
994.
995.
996.
The glucose-clamp technique was used to assess the effect on insulin activity of mixing clinically relevant doses of short- and longer-acting insulins in insulin-treated diabetic subjects. Mixtures of porcine regular and lente insulins resulted in a reduction in activity of the mixture compared with separate injection that was more apparent with premixing for 5 min before injecting than with premixing for 2 min. These findings were not explained by differences in volume of the injected insulin preparations. Mixing of porcine regular and bovine ultralente insulins for 2 min before injecting resulted in a reduced activity compared with separate injection. No difference in activity was obvious for porcine regular and NPH insulins given separately or premixed for 5 min. A reduction of activity during the 1st h after injection was observed when separate injection of one brand of these insulins (Velosulin or Insulatard) was compared with the manufactured mixture (Mixtard). These results indicate that premixing regular and NPH insulins in a 1-to-2 ratio does not alter the biological activity compared with separate administration of the insulins. However, the mixing of regular and insulin-zinc suspensions results in a loss of insulin activity, the magnitude of which depends on the time between mixing and injecting the insulin. The clinical significance of the effect of mixing on the efficacy of subcutaneous insulin therapy should be considered in the context that this is only one of many factors that may affect the activity of subcutaneously injected insulin. 相似文献
997.
S. Gordts 《Journal of assisted reproduction and genetics》1986,3(4):260-261
Conclusion Although more data are needed and it is still too early for a definitive conclusion, GIFT can probably offer new perspectives not only in the treatment of unexplained infertility but also in cases of persistent infertility in patients with LUF (luteinzed unruptured follicle) or a mild degree of endometriosis or when no conception occurs after surgical correction of endometriosis.Only further prospective studies will help us to determine the indications for GIFT. 相似文献
998.
Relationship between transmitter release and presynaptic calcium influx when calcium enters through discrete channels. 总被引:12,自引:2,他引:10 下载免费PDF全文
R S Zucker A L Fogelson 《Proceedings of the National Academy of Sciences of the United States of America》1986,83(9):3032-3036
We have used a three-dimensional diffusion model of calcium entering the presynaptic nerve terminal through discrete channels to simulate experiments relating transmitter release to presynaptic calcium current. The relationship will be less than linear, or will curve downward, if calcium channels are well separated. It will resemble a power-law function with exponent less than the cooperativity of calcium action if channels are clustered closer together. Large presynaptic depolarizations elicit more release than small depolarizations admitting the same calcium influx. This occurs because large pulses open more channels near each other, with the result that the calcium concentration near release sites is greater, due to overlap of calcium diffusing from adjacent channels. 相似文献
999.
Judith D. Goldberg Arnold I. Weiss Kenneth J. Koury 《Journal of clinical periodontology》1986,13(5):411-414
In order to make effective use of the statistical theory of design of clinical trials for chronic diseases such as periodontal disease, certain issues must be considered. Any clinical trial requires that the disease definition be well-specified; that patient eligibility be explicit; that the observation times be explicit; that the duration and endpoint of therapy be specified; that the duration of subsequent followup observation be specified; and that the unit of observation (e.g., tooth, set of teeth, patient) be defined. In a chronic disease, the potential biases that can readily be introduced by self-selection of patients who enter the trial and/or who return for subsequent observation become more important, because subjects are required to remain on treatment and/or observation for prolonged periods. Further, the cyclical nature of some chronic diseases may require special attention to baseline definitions of active disease and disease outcome. These issues are illustrated with examples from clinical trials of hypertension, breast cancer screening, and Polycythemia Vera. Implications for periodontal disease are discussed. 相似文献
1000.
S Pampfer L Vankrieken E Loumaye R De Hertogh K Thomas 《Human reproduction (Oxford, England)》1989,4(4):396-402
Follicular fluids from eight patients with one ovary and from ten patients with two ovaries were investigated for bioactive inhibin, total renin, oestradiol (E2) and progesterone (P4) concentrations. Four follicular fluids were pooled per patient before assessment. All women had been stimulated similarly using a protocol including a GnRH agonist, HMG and HCG. Renin levels were significantly lower and P4 significantly higher in pools of follicular fluid from patients with one ovary, whereas inhibin and E2 concentrations were similar in both patient groups. A significant negative correlation was found in the pools of follicular fluid between inhibin and E2 in both groups. These results suggest a role for inhibin and renin in the paracrine and autocrine control of stimulated follicular development. 相似文献