全文获取类型
收费全文 | 95282篇 |
免费 | 6802篇 |
国内免费 | 1845篇 |
专业分类
耳鼻咽喉 | 1013篇 |
儿科学 | 2164篇 |
妇产科学 | 1865篇 |
基础医学 | 11202篇 |
口腔科学 | 3404篇 |
临床医学 | 9275篇 |
内科学 | 20671篇 |
皮肤病学 | 2026篇 |
神经病学 | 6582篇 |
特种医学 | 2107篇 |
外国民族医学 | 8篇 |
外科学 | 11948篇 |
综合类 | 6427篇 |
现状与发展 | 2篇 |
一般理论 | 22篇 |
预防医学 | 7924篇 |
眼科学 | 2037篇 |
药学 | 7251篇 |
53篇 | |
中国医学 | 2428篇 |
肿瘤学 | 5520篇 |
出版年
2024年 | 195篇 |
2023年 | 960篇 |
2022年 | 2264篇 |
2021年 | 4018篇 |
2020年 | 2605篇 |
2019年 | 2947篇 |
2018年 | 3287篇 |
2017年 | 2658篇 |
2016年 | 2481篇 |
2015年 | 3302篇 |
2014年 | 4501篇 |
2013年 | 5342篇 |
2012年 | 8098篇 |
2011年 | 8270篇 |
2010年 | 5259篇 |
2009年 | 4487篇 |
2008年 | 6169篇 |
2007年 | 6187篇 |
2006年 | 5672篇 |
2005年 | 5254篇 |
2004年 | 4247篇 |
2003年 | 3955篇 |
2002年 | 3399篇 |
2001年 | 798篇 |
2000年 | 696篇 |
1999年 | 688篇 |
1998年 | 600篇 |
1997年 | 525篇 |
1996年 | 456篇 |
1995年 | 395篇 |
1994年 | 327篇 |
1993年 | 257篇 |
1992年 | 344篇 |
1991年 | 308篇 |
1990年 | 251篇 |
1989年 | 236篇 |
1988年 | 227篇 |
1987年 | 192篇 |
1986年 | 208篇 |
1985年 | 173篇 |
1984年 | 165篇 |
1983年 | 148篇 |
1982年 | 119篇 |
1981年 | 136篇 |
1980年 | 119篇 |
1979年 | 121篇 |
1978年 | 77篇 |
1977年 | 99篇 |
1976年 | 85篇 |
1973年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
In an attempt to study further the possible participation of platelets in the pathogenesis of acute poststreptococcal glomerulonephritis (APSGN), we studied the platelet survival time, as an index of platelet activation, in 22 patients with APSGN. Mean platelet survival time was computed from the disappearance of radioactivity from blood, sampled serially after injection of autologous 51Cr-labelled platelets. C1q solid phase ELISA and conglutinin (K) solid phase ELISA were used to measure the serum levels of immune complexes. The platelet survival time in APSGN patients was 113 +/- 10 h vs 197 +/- 10 h in the control group (p less than 0.001); 68% of the patients had a shortened platelet survival, lower than 95% confidence limit. There was a significant increase in the platelet survival in the six patients that were studied after recovery from acute nephritic syndrome. There was no significant association between the mean platelet times survival and CICs (circulating immune complexes). Similarly, no significant correlation was found between the mean platelet lifespan and the severity of the glomerular disease, as assessed by the serum creatinine level and the proteinuria. These results support evidence of platelet activation and consumption in APSGN and we suggest that this activation occurs in the glomeruli capillary wall, due to platelet-vascular wall interaction. 相似文献
42.
Juan J. Muoz Cristina Roca Jos L. Santos Miguel Arroyo Rafael E. de Salamanca 《Basic & clinical pharmacology & toxicology》1993,73(4):189-191
Two alternatives for the treatment of lead intoxication, administration of zinc or a thiol donor, S-adenosyl-L-methionine (SAM), were analysed. Rats were exposed to lead (Pb)-acetate (60 mg/1) in drinking water during 90 days; one group also received SO4Zn in water (40 mg/l), while another received both Pb and SAM (5 mg/24 hr intraperitoneally. Erythrocytic δ-aminolaevulinic dehydratase (ALA-D) activity was significantly reduced (P<0.001) both in rats receiving Pb alone and in rats receiving Pb and each of the other two treatments. The high erythrocytic uroporphyrinogen synthetase (URO-S) activity noticed in Pb administered rats, was significantly (P< 0.001) reduced in animals treated either with zinc or with SAM. Hepatic ALA-D activity tended to decrease while renal enzyme activity was not modified by the low level Pb exposure used in this work. Interestingly, SAM treated rats in both tissues exhibited significantly (P<0.01) higher activities of the enzyme. It is argued that SAM treatment causes a surplus of thiols that allows the full expression of ALA-D catalytic activity. 相似文献
43.
本研究经杀菌试验和免疫后保护力试验探讨小鼠巨噬细胞在抗白色念珠菌感染中的作用,结果表明白色念珠菌酵母形体对巨噬细胞杀伤作用的抵抗力及对小鼠的毒力均较菌丝形体强。小鼠体内不同部位巨噬细胞杀伤白色念珠菌的作用不同,脾脏巨噬细胞作用大于腹腔残存巨噬细胞。经白色念珠菌活菌静脉免疫后脾巨噬细胞杀白色念珠菌作用增强,但其对再感染的抵抗力不增强。 相似文献
44.
The etiological diagnosis of obstruction is difficult during pregnancy. The authors report 3 cases of this rare association: obstruction due to adhesions [1], volvulus of the transverse colon on a common mesentery [1] and obstruction due to an appendix abscess [1]. Complementary investigations, obviously limited under these circumstances, were based on plain abdominal X-rays, repeated if necessary. The diagnosis must be made early and appropriate treatment given in order to ensure a good materno-fetal prognosis as was obtained in these 3 cases. 相似文献
45.
46.
47.
Mnica De la Fuente Juan Jos Garrido Rosa María Arahuetes Angel Hernanz 《Journal of neuroimmunology》1993,42(1)
The neuropeptides neurotensin and neuromedin N (from 10−12 M to 10−9 M) have been showed in this study to stimulate significantly in vitro several steps of the phagocytic process: adherence to substrate, chemotaxis, ingestion of inert particles (latex beads) and production of superoxide anion measured by nitroblue tetrazolium reduction in resting peritoneal macrophages from BALB/c mice. A dose-response relationship was observed, with a maximal stimulation of the phagocytic process at 10−11 M. The two neuropeptides induced no change of intracellular cyclic AMP in murine macrophages. Moreover, adherence and chemotaxis decreased significantly in the presence of EGTA (1 mM), a chelator of extracellular Ca2+, or ryanodine (0.5 mM), a blocker of a Ca2+-gated channel from the endoplasmic reticulum, in both controls and samples with the addition of neurotensin or neuromedin N. These results suggest that there is no relation between the cAMP messenger system and the phagocytic process stimulation in murine peritoneal macrophages by neurotensin or neuromedin N. In addition, the results observed with EGTA and ryanodine could indicate that these two neuropeptides produce their effects through an increase of intracellular Ca2+ concentration. 相似文献
48.
Juan C. Kupferman Charles L. Stewart Frederick J. Kaskel Richard N. Fine 《Pediatric nephrology (Berlin, Germany)》1996,10(2):143-146
Renal and urological anomalies in Down syndrome (DS) have received little attention compared with the nephrourological findings described in other chromosomal abnormalities. Renal hypoplasia, hydroureteronephrosis, ureterovesical and ureteropelvic junction obstruction, and vesicoureteral reflux, but not posterior urethral valves, have been associated with DS. We report the occurrence of posterior urethral valves in three male infants with DS at a single institution. All had multiple urological procedures for correction or palliation of obstruction. Children with DS may have an increased risk for developing posterior urethral valves and obstructive uropathy. Furthermore, they may also develop chronic renal failure secondary to posterior urethral valves. Therefore, we suggests that infants with DS be screened with ultrasonography for renal and urological abnormalities early in life and, if abnormal, a contrast voiding cystourethrogram be performed to rule out posterior urethral valves or other bladder or urethral abnormalities. A review of the renal and urological anomalies in DS reported in the literature since 1960 is presented. 相似文献
49.
不同术后镇痛模式对红细胞免疫功能的影响 总被引:4,自引:1,他引:3
目的探讨不同术后镇痛模式对红细胞免疫功能的影响。方法50例妇科手术患者,按术后不同镇痛模式分为硬膜外自控镇痛(PCEA)组和静脉自控镇痛(PCIA)组。并分别于术前、术后1、3、7 d采静脉血样检测红细胞C3b受体花环率(RCR)、红细胞免疫复合物花环率(RICR)、红细胞免疫粘附促进因子(RFER)和红细胞免疫粘附抑制因子(RFIR)。结果与术前比,PCEA组术后1 d RCR、RFER显著上升(P<0.05),RFIR显著下降(P<0.05),术后3 d RCR、RFER仍显著上升(P<0.05),而RICR显著下降(P<0.05);PCIA组术后1 d RCR、RFER显著下降(P<0.05),RFIR、RICR显著上升(P<0.05);PCIA组术后1、3 d RCR、RFER比PCEA组显著降低(P<0.05),而RICR显著上升(P<0.05);两组各参数在术后7 d基本恢复至术前水平。结论PCEA对红细胞免疫功能的稳定和恢复作用明显强于PCIA。 相似文献
50.