全文获取类型
收费全文 | 1429761篇 |
免费 | 97946篇 |
国内免费 | 2080篇 |
专业分类
耳鼻咽喉 | 18693篇 |
儿科学 | 47364篇 |
妇产科学 | 39977篇 |
基础医学 | 210683篇 |
口腔科学 | 39699篇 |
临床医学 | 130523篇 |
内科学 | 277195篇 |
皮肤病学 | 31124篇 |
神经病学 | 111877篇 |
特种医学 | 56117篇 |
外国民族医学 | 356篇 |
外科学 | 203485篇 |
综合类 | 26914篇 |
现状与发展 | 3篇 |
一般理论 | 569篇 |
预防医学 | 118695篇 |
眼科学 | 31813篇 |
药学 | 103919篇 |
10篇 | |
中国医学 | 2212篇 |
肿瘤学 | 78559篇 |
出版年
2018年 | 16853篇 |
2017年 | 14056篇 |
2016年 | 14280篇 |
2015年 | 17624篇 |
2014年 | 21953篇 |
2013年 | 30598篇 |
2012年 | 46702篇 |
2011年 | 44302篇 |
2010年 | 25086篇 |
2009年 | 25762篇 |
2008年 | 39610篇 |
2007年 | 42930篇 |
2006年 | 42762篇 |
2005年 | 49335篇 |
2004年 | 49212篇 |
2003年 | 43513篇 |
2002年 | 37952篇 |
2001年 | 59357篇 |
2000年 | 58440篇 |
1999年 | 52606篇 |
1998年 | 13847篇 |
1997年 | 12453篇 |
1996年 | 12919篇 |
1995年 | 12219篇 |
1994年 | 11394篇 |
1992年 | 43398篇 |
1991年 | 43104篇 |
1990年 | 42064篇 |
1989年 | 40620篇 |
1988年 | 37747篇 |
1987年 | 36935篇 |
1986年 | 35198篇 |
1985年 | 32879篇 |
1984年 | 24801篇 |
1983年 | 21474篇 |
1982年 | 12174篇 |
1979年 | 23990篇 |
1978年 | 17272篇 |
1977年 | 14206篇 |
1976年 | 13117篇 |
1975年 | 14822篇 |
1974年 | 18170篇 |
1973年 | 17621篇 |
1972年 | 16796篇 |
1971年 | 15846篇 |
1970年 | 14908篇 |
1969年 | 14140篇 |
1968年 | 13130篇 |
1967年 | 11901篇 |
1966年 | 11200篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Critically ill cardiac patients often undergo mechanical ventilation. The interplay between pulmonary and cardiac mechanics is complicated and in many cases may result in impaired transfer of O2 from the atmosphere to the tissues. This article addresses the principles of pulmonary and peripheral gas exchange, as well as the mechanical effects of respiration on the circulation. 相似文献
994.
T E Porter B M Hargis J L Silsby M E el Halawani 《General and comparative endocrinology》1989,74(3):400-405
This study was conducted to determine if lower steroid secretion by the small white follicles in incubating turkey hens contributes to lower circulating steroid concentrations during this time. Turkey hens were grouped as either laying or incubating. Serum samples and the ovarian small white follicles (SWF; 2-7 mm diameter) were collected from each hen. The SWF were pooled for each group and their cells were dispersed by trypsin digestion. Serum-luteinizing hormone (LH), progesterone (P), testosterone (T), and estradiol (E) concentrations were lower and serum prolactin concentration was higher during incubation than during egg laying. SWF cells from incubating hens secreted more P and T and less E in response to ovine luteinizing hormone (oLH) than did similar cell suspensions from laying hens. The incubating hens' SWF cells' capacity to secrete E but not their capacity to secrete P or T in vitro is consistent with the observed circulating levels. It is hypothesized that lower levels of circulating LH and/or higher levels of prolactin found in incubating hens may have a depressing effect on aromatase activity and/or an up-regulating effect on LH-induced P and T secretion by the SWF cells. 相似文献
995.
Intestinal infarction caused by carcinoid associated elastic vascular sclerosis: early presentation of a small ileal carcinoid tumour. 总被引:2,自引:1,他引:1 下载免费PDF全文
We describe a patient with extensive ischaemic necrosis of the ileum as a result of elastic vascular sclerosis (EVS). A 2 cm carcinoid tumour was located nearby with microscopic evidence of spread to regional lymph nodes. Severe intestinal ischaemia caused by carcinoid associated EVS may be the presenting feature of small carcinoid tumours resulting in their early diagnosis. 相似文献
996.
997.
A preliminary report of the short-term effect of carbonated beverage consumption on calcium metabolism in normal women 总被引:2,自引:0,他引:2
S Smith J Swain E M Brown G Wyshak T Albright V A Ravnikar I Schiff 《Archives of internal medicine》1989,149(11):2517-2519
A variety of nutritional factors influence the bioavailability of calcium and increase a woman's risk of osteoporosis. Eight healthy women completed an 8-week metabolic study designed to investigate the effect of nonalcoholic carbonated beverage consumption on calcium metabolism. Compared with women receiving a control diet, women consuming a diet high in nonalcoholic carbonated beverages demonstrated similar mean serum levels of calcium, ionized calcium, phosphorus, alkaline phosphatase, parathyroid hormone, 1,25-dihydroxyvitamin D3, and osteocalcin. Twenty-four-hour urine volume, creatinine clearance, calcium-creatinine ratio, and phosphorus-creatinine ratio were similar during consumption of the diet high in nonalcoholic carbonated beverages and the control diet. Twenty-four-hour cyclic adenosine monophosphate-creatinine ratio was significantly lower in women consuming the diet high in nonalcoholic carbonated beverage compared with women receiving the control diet (342 +/- 27.4 nmol/mmol vs 409 +/- 22.1 nmol/mmol). Consumption of a diet high in nonalcoholic carbonated beverages on a short-term basis does not appear to affect adversely the serum or urinary markers of calcium metabolism. 相似文献
998.
999.
1000.
Prospective randomized comparison of mezlocillin therapy alone with combined ampicillin and gentamicin therapy for patients with cholangitis 总被引:3,自引:0,他引:3
W B Gerecht N K Henry W W Hoffman S M Muller N F LaRusso J E Rosenblatt W R Wilson 《Archives of internal medicine》1989,149(6):1279-1284
Forty-six patients with cholangitis were randomized to receive therapy with mezlocillin sodium (24 patients) or a combination of ampicillin sodium--gentamicin sulfate (22 patients). The biliary concentration of mezlocillin was 112 times higher than that of ampicillin and 778 times higher than that of gentamicin. The ratio of the concentration in serum or bile over the minimum inhibitory concentration against aerobic gram-negative bacilli (therapeutic index) was higher for mezlocillin than for either ampicillin or gentamicin. Twenty (83%) of 24 patients were cured following mezlocillin therapy compared with 9 (41%) of 22 patients after ampicillin-gentamicin therapy. The 3 patients with superinfection were in the ampicillin-gentamicin arm of the study. Fewer toxic or adverse effects occurred in association with mezlocillin treatment than with ampicillin-gentamicin treatment. Mezlocillin therapy was more effective, less toxic, and less expensive than treatment with ampicillin and gentamicin for patients with cholangitis. 相似文献