全文获取类型
收费全文 | 296589篇 |
免费 | 17636篇 |
国内免费 | 412篇 |
专业分类
耳鼻咽喉 | 4213篇 |
儿科学 | 10296篇 |
妇产科学 | 10277篇 |
基础医学 | 45052篇 |
口腔科学 | 7508篇 |
临床医学 | 24293篇 |
内科学 | 55923篇 |
皮肤病学 | 6328篇 |
神经病学 | 21043篇 |
特种医学 | 11648篇 |
外国民族医学 | 43篇 |
外科学 | 46807篇 |
综合类 | 7789篇 |
现状与发展 | 1篇 |
一般理论 | 160篇 |
预防医学 | 19949篇 |
眼科学 | 6959篇 |
药学 | 20909篇 |
中国医学 | 787篇 |
肿瘤学 | 14652篇 |
出版年
2018年 | 3629篇 |
2017年 | 2663篇 |
2016年 | 3078篇 |
2015年 | 3495篇 |
2014年 | 4591篇 |
2013年 | 7219篇 |
2012年 | 9082篇 |
2011年 | 9460篇 |
2010年 | 6145篇 |
2009年 | 5559篇 |
2008年 | 8687篇 |
2007年 | 9546篇 |
2006年 | 9377篇 |
2005年 | 8977篇 |
2004年 | 8678篇 |
2003年 | 8185篇 |
2002年 | 7779篇 |
2001年 | 13349篇 |
2000年 | 13670篇 |
1999年 | 11443篇 |
1998年 | 3034篇 |
1997年 | 2801篇 |
1996年 | 2644篇 |
1995年 | 2549篇 |
1994年 | 2352篇 |
1992年 | 8345篇 |
1991年 | 8477篇 |
1990年 | 8289篇 |
1989年 | 8105篇 |
1988年 | 7332篇 |
1987年 | 7105篇 |
1986年 | 6739篇 |
1985年 | 6537篇 |
1984年 | 4775篇 |
1983年 | 4135篇 |
1982年 | 2483篇 |
1979年 | 4445篇 |
1978年 | 3237篇 |
1977年 | 2741篇 |
1976年 | 2516篇 |
1975年 | 2842篇 |
1974年 | 3356篇 |
1973年 | 3366篇 |
1972年 | 3124篇 |
1971年 | 2955篇 |
1970年 | 2842篇 |
1969年 | 2583篇 |
1968年 | 2540篇 |
1967年 | 2376篇 |
1966年 | 2266篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
O H Sherman 《Clinics in Sports Medicine》1987,6(3):491-502
This article has described the perioperative management of the arthroscopic patient. As emphasized, preoperative planning requires a precise diagnosis, patient education, and selective procedures. The operative management is sophisticated, exacting, and challenging, as discussed in other articles of this issue. Finally, the postoperative management is specifically directed toward pathology and procedure. Recovery times are variable, and complications are not insignificant and can lead to prolonged patient morbidity and financial loss. It is important to consider patient goals versus reality, patient willingness to opt for acceptable versus optimal results, and if the procedure is necessary versus justified versus contraindicated. If all of these factors are kept in mind by the surgeon and conveyed to the patient, arthroscopic surgery can be extremely rewarding to both. 相似文献
992.
Comparative aspects of herbicide metabolism 总被引:1,自引:0,他引:1
H O Esser 《Xenobiotica; the fate of foreign compounds in biological systems》1986,16(10-11):1031-1045
Herbicides are the economically most important group of pesticides, and such activity occurs in a wide range of chemical structural classes. Studies of the metabolism of herbicides involve a great number of organisms and test systems to provide information of value for assessing the nature of potential residues in human foods of plant and animal origin, metabolism-toxicity relationships in mammals in view of potential human exposure, and in plants in view of biological selectivity, and the environmental fate in soil and aquatic systems. Some of the objectives pursued in an industrial metabolism laboratory and the problems confronted when elaborating its contribution to the safety assessment of a pesticide are briefly described with special reference to metabolism-selectivity relationships in plants and the significance of plant metabolites to animals. 相似文献
993.
994.
Accurate determination of renal function in patients with intestinal urinary diversions 总被引:2,自引:0,他引:2
The regular determination of renal function is a critical part of the management of patients who have had the urinary tract reconstructed with intestinal segments. These intestinal segments reabsorb urinary solutes and, thereby, complicate the determination of renal function by conventional methods. Urinary clearances of urea, creatinine and inulin were performed in patients with intestinal segments in the urinary tract and controls under varying diuretic conditions. Patients with intestinal diversions also underwent radioisotopic determination of renal function. The urinary clearances of urea, creatinine and inulin are highly dependent on the rate of urine flow in patients with intestinal segments in the urinary tract. Diuresis maximizes the urinary clearances of these solutes by minimizing intestinal reabsorption. Creatinine clearance prediction from the serum creatinine underestimates true glomerular filtration rate. Radioisotopic determination of renal function correlates poorly with true glomerular filtration rate. Only creatinine clearance measured under diuretic conditions correlates well with true renal function. Urine concentrating ability cannot be assessed accurately in patients with intestinal segments in the urinary tract, since osmolality rapidly equilibrates across the segments. 相似文献
995.
996.
We have evaluated the in vitro effects of bromocriptine (Br), on the hepatic cytochrome P-450 monooxygenase system of rats pretreated with saline phenobarbitone (PB) and beta-naphthoflavone (BNF). Br inhibited ethoxyresorufin O-dealkylase (EROD) activity in liver microsomes of rats pretreated with saline and PB but not in BNF pretreated animals. Maximum inhibition of EROD activity by Br in the microsomes of saline and PB pretreated rats were 50%-60% of the control. In contrast, a dual effect was observed on aminopyrine N-demethylase activity (APD) by Br in microsomes of saline, PB and BNF pretreated rats. At a low concentration (25 microM), Br inhibited the activity of APD to a similar extent in all pretreatment groups; however, with higher concentrations of Br (50 microM to 300 microM), enhancement of APD activity was observed. Br (300 microM) increased the APD activity to 2-3 times the control level in microsomes of rats pretreated with saline, PB or BNF. Spectral studies revealed a Type II binding of Br to cytochrome P-450 from microsomes of saline and PB pretreated rats. A reverse type I binding was observed for BNF induced microsomes. In addition, Br also enhanced NADPH cytochrome c (P-450) reductase activity to a similar extent in all pretreatment groups. These results suggest that the inhibition of EROD activity may be due to direct binding by Br to certain isozymes of cytochrome P-450 and that the enhancing effect of Br on APD activity may be in part due to the activation of the NADPH cytochrome c reductase component of the cytochrome P-450 monooxygenase system. 相似文献
997.
Effect of dietary zinc deficiency on the endogenous phosphorylation and dephosphorylation of rat erythrocyte membrane 总被引:1,自引:0,他引:1
The effect of dietary zinc deficiency on patterns of phosphorylation and dephosphorylation of rat erythrocyte membrane proteins and erythrocyte filterability was examined. Weanling male Wistar rats were fed an egg white-based diet containing less than 1.1 mg zinc/kg diet ad libitum for 3 wk. Control rats were either pair-fed or ad libitum-fed the basal diet supplemented with 100 mg zinc/kg diet. Net phosphorylation and dephosphorylation of erythrocyte membrane proteins were carried out by an in vitro assay utilizing [gamma-32P]ATP. The membrane proteins were subsequently separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the 32P content of gel slices was counted by Cerenkov counting. Erythrocyte filterability was measured as the filtration time of suspensions of erythrocytes, both untreated and preincubated with diamide, under constant pressure. Erythrocyte ghosts from zinc-deficient rats demonstrated greater dephosphorylation of protein bands R1 plus R2 and R7 than pair-fed rats and greater net phosphorylation of band R2.2 than pair-fed or ad libitum-fed control rats (P less than 0.05). Erythrocytes from ad libitum-fed control rats showed significantly longer filtration times than those from zinc-deficient or pair-fed control rats. In conclusion, dietary zinc deficiency alters in vitro patterns of erythrocyte membrane protein phosphorylation and dephosphorylation, whereas the depression in food intake associated with the zinc deficiency increases erythrocyte filterability. 相似文献
998.
O Crivello J G Luz J B Lemos J R Rezende 《Revue de stomatologie et de chirurgie maxillo-faciale》1989,90(2):100-103
Statistical analysis of 550 isolated maxillo-facial fractures is presented. Data obtained illustrated the important number of maxillo-facial fractures in Sao Paulo, the automobilistics accidents were responsible for most maxillo-facial trauma, the jaw and the malar were more predominant than the others structures and the conservative treatment was the most used one. 相似文献
999.
N B Shalygina G K Shepeleva O S Astrina Kh D Lomazova A M Poliakova 《Arkhiv patologii》1987,49(2):27-32
Histological and biomicroscopic methods were used to study the effects of toxic lemic and meningococcal microbial fractions on mesenteric blood microcirculation in rats. Aggregation ability of red blood cells and thrombocytes was investigated. The sublethal dose of meningococcal toxins was shown to induce marked impairment in the blood microcirculation 30 minutes after intravenous administration. The lethal dose of lemic toxins manifests itself later (in 2-4 hours). Meningococcal toxins are characterized by the increase in the aggregation ability of erythrocytes and thrombocytes in initial observation periods; lemic toxins increase the thrombocyte aggregation and produce almost no effect on erythrocyte aggregation. 相似文献
1000.