全文获取类型
收费全文 | 20060篇 |
免费 | 1298篇 |
国内免费 | 101篇 |
专业分类
耳鼻咽喉 | 271篇 |
儿科学 | 430篇 |
妇产科学 | 417篇 |
基础医学 | 2502篇 |
口腔科学 | 614篇 |
临床医学 | 1659篇 |
内科学 | 5172篇 |
皮肤病学 | 442篇 |
神经病学 | 1716篇 |
特种医学 | 470篇 |
外科学 | 3366篇 |
综合类 | 132篇 |
一般理论 | 8篇 |
预防医学 | 1189篇 |
眼科学 | 607篇 |
药学 | 1060篇 |
1篇 | |
中国医学 | 42篇 |
肿瘤学 | 1361篇 |
出版年
2023年 | 135篇 |
2022年 | 240篇 |
2021年 | 693篇 |
2020年 | 365篇 |
2019年 | 602篇 |
2018年 | 747篇 |
2017年 | 428篇 |
2016年 | 486篇 |
2015年 | 610篇 |
2014年 | 827篇 |
2013年 | 1011篇 |
2012年 | 1713篇 |
2011年 | 1768篇 |
2010年 | 922篇 |
2009年 | 852篇 |
2008年 | 1375篇 |
2007年 | 1434篇 |
2006年 | 1299篇 |
2005年 | 1170篇 |
2004年 | 1014篇 |
2003年 | 859篇 |
2002年 | 796篇 |
2001年 | 110篇 |
2000年 | 86篇 |
1999年 | 140篇 |
1998年 | 177篇 |
1997年 | 133篇 |
1996年 | 116篇 |
1995年 | 129篇 |
1994年 | 113篇 |
1993年 | 113篇 |
1992年 | 93篇 |
1991年 | 63篇 |
1990年 | 51篇 |
1989年 | 51篇 |
1988年 | 49篇 |
1987年 | 41篇 |
1986年 | 49篇 |
1985年 | 39篇 |
1984年 | 56篇 |
1983年 | 48篇 |
1982年 | 59篇 |
1981年 | 58篇 |
1980年 | 39篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1977年 | 32篇 |
1976年 | 26篇 |
1974年 | 21篇 |
1973年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 803 毫秒
111.
112.
113.
The potential for a bioterrorism-induced smallpox outbreak has been much discussed of late. The literature of the late 1960s stressed that the distinction between smallpox and the other viral-induced vesicle-forming diseases, namely varicella zoster and disseminated herpes simplex, was difficult to make. Given that the cutaneous manifestations of smallpox would be among the initial symptoms, we reviewed 2 cases of smallpox diagnosed in South America in the 1970s in conjunction with 9 cases of multiple skin vesicles diagnosed as either disseminated herpes simplex or varicella-zoster. These were examined by routine hematoxylin and eosin stain (H&E) as well as by in situ hybridization. A blind review of the cases demonstrated that each showed striking intraepithelial vesicles containing multinucleated squamous cells exhibiting a ground glass appearance of the nuclear chromatin. Thus, as expected, routine H&E examination could not differentiate the 2 smallpox cases from the other 9 samples. In situ hybridization easily distinguished the 2 cases of smallpox from the other 9 samples, 5 of which contained varicella-zoster (two had been misdiagnosed as herpes) and the other 4 were disseminated herpes simplex. The in situ test, readily accomplished in any histology-based molecular laboratory in 4 hours, allows for the rapid and specific identification of smallpox infection and, importantly, its distinction from its mimics. Formalin fixation, which is optimal for in situ hybridization, guarantees the inactivation of the smallpox virus. 相似文献
114.
115.
Systemic Administration of Immunostimulatory DNA Sequences Mediates Reversible Inhibition of Th2 Responses in a Mouse Model of Asthma 总被引:10,自引:0,他引:10
Broide DH Stachnick G Castaneda D Nayar J Miller M Cho JY Roman M Zubeldia J Hayashi T Raz E Hyashi T 《Journal of clinical immunology》2001,21(3):175-182
This study investigated whether immunostimulatory DNA sequences (ISS) induce a transient or sustained inhibition of Th2 responses to inhaled antigen. We sensitized mice with subcutaneous injections to develop a Th2 response to ovalbumin (ova) and then administered a dose of ISS prior to ova inhalation challenge. Mice were then rechallenged with ova by inhalation a second time at varying time points after the first ova inhalation (1 to 8 weeks later) to determine whether the ISS dose administered prior to the first ova inhalation protected against a subsequent second ova inhalation challenge. A single dose of ISS inhibited the Th2 response to the first inhalation of ova antigen, as well as 4 weeks later to the second inhalation of ova. However, ISS did not inhibit a Th2 response to the second inhalation of ova 8 weeks later. The reversible inhibition of Th2 responses at 8 weeks suggests the need for repeated ISS administration at monthly intervals. 相似文献
116.
117.
The restorative effect of naps on perceptual deterioration 总被引:4,自引:0,他引:4
Mednick SC Nakayama K Cantero JL Atienza M Levin AA Pathak N Stickgold R 《Nature neuroscience》2002,5(7):677-681
Human performance on visual texture discrimination tasks improves slowly (over days) in the absence of additional training. This 'slow learning' requires nocturnal sleep after training and is limited to the region of visual space in which training occurred. Here, we tested human subjects four times in one day and found that with repeated, within-day testing, perceptual thresholds actually increased progressively across the four test sessions. This performance deterioration was prevented either by shifting the target stimuli to an untrained region of visual space or by having the subjects take a mid-day nap between the second and third sessions. 相似文献
118.
119.
Sandra Sabatini Venkateswararao Alla Allen Wilson Manuel Cruz-Soto April de White Neil A. Kurtzman Jose A. L. Arruda 《Pflügers Archiv : European journal of physiology》1982,393(3):262-268
Complete papillary necrosis in rats can be induced within 1 month following a single injection of 2-bromoethylamine hydrobromide (BEA) (50 mg, i.v.). Utilizing a combination of clearance and balance techniques the effects of complete absence of the papilla was examined as regards urinary acidification, whole kidney glomerular filtration rate (GFR), single nephron GFR, and morphology. Whole kidney GFR was not different from control, however, the percent filtering juxtamedullary nephrons was markedly diminished (87.2±2.1 vs. 31.5±3.6% filtering, control vs. BEA, respectively,P<0.001) and significantly reduced in the superficial nephrons (80.6±3.6 vs. 62.2±6.1% filtering, control vs. BEA, respectively,P<0.05). There was a significant decrease in juxtamedullary single nephron GFR and an increase in the superficial single nephron GFR as assessed by the quantitative Hanssen's technique in the animals with chronic papillary necrosis. Complete papillary necrosis was associated with normal arterial bicarbonate concentration, pH, and plasma electrolyte concentrations. At the same degree of acidemia (induced by NH4Cl administration) minimal urinary pH, ammonium excretion, and titratable acid excretion were not different than seen in age matched controls. The response to Na2SO4 infusion and phosphate infusion was the same in both groups of animals. The urineblood (U-B)pCO2, an index of urinary acidification, was identical in BEA and control animals. Scanning electron microscopy showed scarring of the juxtamedullary glomeruli one month after BEA. The papilla was sloughed and lying free in the renal pelvis in every experimental animal. These data demonstrate that complete papillary necrosis is not associated with acidosis nor a defect in urinary acidification. 相似文献
120.
Juan C. Rueda Luis Ortega Jesus M. Argüello Antonio J. Torres Ignacio Landa Jose L. Balibrea 《Virchows Archiv : an international journal of pathology》1992,420(2):117-120
Summary Retrograde injection of 5% sodium taurocholic acid (TA) in Wistar rat pancreatic duct is followed by acute pancreatitis, resulting
in 100% mortality within 36 h. Biochemical determinations show raised levels of amylase in ascites and blood. Necrosis has
been measured using seven morphometric characteristics of pathological changes that add precise information on the type and
extension of the pancreatic lesion. The percentage of necrotic tissue (by area) seems to be the most objective parameter.
Necrosis appears 6 h after TA infusion, being 5.77% in extent after 12h, 14.9% after 24 h and animals die with an area of
29.5% necrosis. This experimental model seems to one in which physiopathological and therapeutic trials on acute pancreatitis
may be camed out. 相似文献