全文获取类型
收费全文 | 10906篇 |
免费 | 872篇 |
国内免费 | 97篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 506篇 |
妇产科学 | 214篇 |
基础医学 | 1546篇 |
口腔科学 | 469篇 |
临床医学 | 1116篇 |
内科学 | 2271篇 |
皮肤病学 | 266篇 |
神经病学 | 891篇 |
特种医学 | 682篇 |
外科学 | 1542篇 |
综合类 | 157篇 |
一般理论 | 6篇 |
预防医学 | 712篇 |
眼科学 | 131篇 |
药学 | 641篇 |
2篇 | |
中国医学 | 23篇 |
肿瘤学 | 604篇 |
出版年
2023年 | 115篇 |
2022年 | 79篇 |
2021年 | 400篇 |
2020年 | 238篇 |
2019年 | 297篇 |
2018年 | 368篇 |
2017年 | 241篇 |
2016年 | 257篇 |
2015年 | 279篇 |
2014年 | 379篇 |
2013年 | 436篇 |
2012年 | 625篇 |
2011年 | 596篇 |
2010年 | 388篇 |
2009年 | 343篇 |
2008年 | 448篇 |
2007年 | 472篇 |
2006年 | 404篇 |
2005年 | 416篇 |
2004年 | 323篇 |
2003年 | 318篇 |
2002年 | 302篇 |
2001年 | 273篇 |
2000年 | 248篇 |
1999年 | 213篇 |
1998年 | 217篇 |
1997年 | 220篇 |
1996年 | 194篇 |
1995年 | 160篇 |
1994年 | 166篇 |
1993年 | 149篇 |
1992年 | 152篇 |
1991年 | 160篇 |
1990年 | 151篇 |
1989年 | 178篇 |
1988年 | 146篇 |
1987年 | 146篇 |
1986年 | 142篇 |
1985年 | 136篇 |
1984年 | 87篇 |
1983年 | 67篇 |
1982年 | 56篇 |
1981年 | 59篇 |
1980年 | 67篇 |
1979年 | 66篇 |
1978年 | 50篇 |
1976年 | 55篇 |
1974年 | 54篇 |
1972年 | 54篇 |
1971年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
51.
Bone marrow fat content in relation to bone remodeling and serum chemistry in intact and ovariectomized dogs 总被引:6,自引:0,他引:6
R. Bruce Martin Ph.D. Betty D. Chow Paul A. Lucas 《Calcified tissue international》1990,46(3):189-194
Summary It was previously shown that 11 months after ovariectomy the volume fraction of trabecular bone in the spine and 11th rib
medullary canal of Beagle dogs (6 control, 9 ovariectomized) was significantly reduced. In this paper it is shown that these
changes are accompanied by increased marrow fat volume in the 11th rib (59.0±9.5% vs. 44.3 ±10.0%). Conversely, the volume
fraction of functional (hematopoietic) cells in the marrow was reduced by ovariectomy. Additionally, variations in marrow
fat volume were tested for correlation with 22 other variables pertinent to bone physiology. Marrow fat volume was significantly
positively correlated with serum osteocalcin, rib trabecular bone porosity, rib cross-sectional area, and gains in body weight.
It was negatively correlated with serum estrogen concentrations and the extent of rib trabecular surfaces labeled with tetracycline. 相似文献
52.
JI Elizalde ; J Clemente ; JL Marin ; J Panes ; B Aragon ; A Mas ; JM Pique ; J Teres 《Transfusion》1997,37(6):573-576
BACKGROUND: Equilibration of hemoglobin concentration after transfusion has been estimated to take about 24 hours, but some studies have shown that earlier measurements reflect steady-state values in persons who have not bled recently. This study was aimed at assessing the changes over time in hemoglobin concentration after transfusion in acutely anemic patients because of recent bleeding. STUDY DESIGN AND METHODS: Thirty-two normovolemic patients recovering from an acute bleeding episode who were no longer thought to be bleeding and who received a 2- unit red cell transfusion were studied. At baseline and 15, 30, 60, and 120 minutes and 24 hours after transfusion, hemoglobin concentration and hematocrit values were measured. RESULTS: The administration of 2 units of packed red cells elicited a 24-hour increase of 22.4 +/− 6.8 g per L in hemoglobin concentration. Hemoglobin values were not different at any of the defined posttransfusion times. Hematocrit levels experienced similar changes over time. Agreement between 15-minute and 24-hour values was excellent, as only 6 percent of patients exhibited a clinically significant difference (> 6 g/L) between the hemoglobin measurements. CONCLUSION: Hemoglobin and hematocrit values rapidly equilibrate after transfusion in normovolemic patients who are recovering from an acute bleeding episode. This fact would allow a rapid assessment of the effects of transfusion and of the recurrence of bleeding in patients remaining at risk. 相似文献
53.
Tuberculosis and HIV infection in sub-Saharan Africa. 总被引:23,自引:0,他引:23
54.
Andres A; Morales JM; Praga M; Campo C; Lahera V; Garcia-Robles R; Rodicio JL; Ruilope LM 《Nephrology, dialysis, transplantation》1997,12(7):1437-1440
BACKGROUND: Cyclosporin has been shown to facilitate renal vasoconstriction
and to have an antinatriuretic effect. The existence of an interference of
cyclosporin with the vasodilating properties of endothelium mediated by
nitric oxide production could mediate these effects. On the other hand, the
infusion of the nitric oxide precursor L-arginine has been shown to induce
renal vasodilatation and to facilitate natriuresis in normal volunteers. We
have investigated the renal effects of the administration of an infusion of
L-arginine in renal transplant patients chronically treated with
cyclosporin. To facilitate the analysis of the data the effects of the
administration of a similar dose of cyclosporin on renal function during
the infusion of a vehicle were also investigated during the administration
of a vehicle of L-arginine. DESIGN: Ten male renal transplant patients,
chronically treated with cyclosporin and with a stable renal function were
studied during 2 consecutive days after the administration of the usual
morning dose of cyclosporin. The first day they received an intravenous
infusion of vehicle and the second the infusion of graded doses of
L-arginine (50, 100, 150 mg/kg/h) during 3 consecutive h. RESULTS: The
first day, after cyclosporin administration a significant fall (P <
0.01) was observed in natriuresis and kaliuresis in the absence of changes
in renal plasma flow and glomerular filtration rate. After the
administration of L-arginine significant (P < 0.01) increases of renal
plasma flow, glomerular filtration rate, and natriuresis were seen. The
increase in blood levels of cyclosporin after its administration did not
differ between days 1 and 2. CONCLUSION: These results indicate that
L-arginine facilitates renal vasodilatation and natriuresis in renal
transplant patients. Furthermore, the observed increase in sodium excretion
could indicate that L-arginine counteracts the antinatriuretic effect of
cyclosporin.
相似文献
55.
56.
57.
Variants of B cell lymphoma 6 (BCL6) and marked atopy 总被引:3,自引:0,他引:3
Chaker N Adra PS Gao XQ Mao Beverly W Baron S. Pauker T. Miki T. Shirakawa JM Hopkin 《Clinical genetics》1998,54(4):362-364
58.
59.
Twelve patients with progressive renal failure were placed on a very low protein diet supplemented by an essential amino acid-keto acid mixture for six to twelve months. Total daily intake was 0.04 g nitrogen/kg and 50 kcal/kg. Eight subjects had a significant change in the slope of reciprocal plasma creatinine, becoming less steep and in two cases positive. GFR did not improve, but in four patients the decline over twelve months was less than 0.5 mliter/min. There were significant falls in blood and urinary urea, serum phosphate PTH and calcium X phosphate product. Body wt decreased during the first three months. Arm muscle circumference fell by 0.9 cm (P less than 0.005). Serum albumin and transferrin levels did not change significantly. Muscle mass and plasma creatinine fell simultaneously in several patients. Creatinine excretion per kg muscle mass, assessed anthropometrically, declined by 21% in the first three months. This diet may slow the decline in renal function in a proportion of patients. However, muscle mass can be lost. Serum protein levels do not accurately reflect nutritional changes. A fall in plasma creatinine may not be due to improved GFR but instead to altered creatinine metabolism. 相似文献
60.
Our observation concerns a patient aged 29 who has presented for the last two years a smooth lesion, non-infiltrated, golden yellow, and situated on the interior surface of the left knee. This lesion recalls the lichen aureus confirmed by standard histology nad Perls' coloration. There is capillary fragility without plaque anomaly. There is, however, no sign of subjacent venous incompetence. 相似文献