全文获取类型
收费全文 | 197703篇 |
免费 | 2568篇 |
国内免费 | 100篇 |
专业分类
耳鼻咽喉 | 1423篇 |
儿科学 | 7215篇 |
妇产科学 | 3431篇 |
基础医学 | 20007篇 |
口腔科学 | 2090篇 |
临床医学 | 14546篇 |
内科学 | 35430篇 |
皮肤病学 | 1252篇 |
神经病学 | 19251篇 |
特种医学 | 9561篇 |
外科学 | 30952篇 |
综合类 | 2439篇 |
一般理论 | 15篇 |
预防医学 | 19895篇 |
眼科学 | 3280篇 |
药学 | 10839篇 |
中国医学 | 701篇 |
肿瘤学 | 18044篇 |
出版年
2024年 | 38篇 |
2023年 | 221篇 |
2022年 | 427篇 |
2021年 | 740篇 |
2020年 | 491篇 |
2019年 | 705篇 |
2018年 | 22523篇 |
2017年 | 17824篇 |
2016年 | 20079篇 |
2015年 | 1683篇 |
2014年 | 1717篇 |
2013年 | 1893篇 |
2012年 | 8771篇 |
2011年 | 22859篇 |
2010年 | 19776篇 |
2009年 | 12381篇 |
2008年 | 20978篇 |
2007年 | 23149篇 |
2006年 | 1987篇 |
2005年 | 3539篇 |
2004年 | 4645篇 |
2003年 | 5474篇 |
2002年 | 3457篇 |
2001年 | 479篇 |
2000年 | 583篇 |
1999年 | 370篇 |
1998年 | 413篇 |
1997年 | 390篇 |
1996年 | 221篇 |
1995年 | 203篇 |
1994年 | 188篇 |
1993年 | 123篇 |
1992年 | 110篇 |
1991年 | 157篇 |
1990年 | 191篇 |
1989年 | 143篇 |
1988年 | 121篇 |
1987年 | 95篇 |
1986年 | 74篇 |
1985年 | 84篇 |
1984年 | 48篇 |
1983年 | 56篇 |
1982年 | 53篇 |
1980年 | 64篇 |
1974年 | 33篇 |
1970年 | 35篇 |
1968年 | 33篇 |
1938年 | 62篇 |
1932年 | 57篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
962.
963.
Ulrike Heider Corinna Langelotz Christian Jakob Ivana Zavrski Claudia Fleissner Jan Eucker Kurt Possinger Lorenz C Hofbauer Orhan Sezer 《Clinical cancer research》2003,9(4):1436-1440
PURPOSE: Increased bone resorption is a hallmark of multiple myeloma and is attributable to osteoclast activation. Recent studies showed that the receptor activator of nuclear factor kappaB ligand (RANKL) is the key mediator of osteoclastogenesis and plays a crucial role in bone destruction in malignant bone disease. We found that human myeloma cells express RANKL and analyzed the association of the RANKL expression with the presence of osteolytic bone disease in patients with multiple myeloma. EXPERIMENTAL DESIGN: Flow cytometry was performed on bone marrow samples derived from controls and multiple myeloma patients with or without osteolytic bone lesions on conventional radiography. Plasma cells were identified as CD38++/CD138+ cells. The level of RANKL expression on the surface of bone marrow plasma cells was correlated with the bone status of the patients. RESULTS: The bone marrow plasma cells from controls showed no or only a weak surface expression of RANKL, and the median mean fluorescence index (MFI) was 6. In contrast, expression of RANKL could be detected on bone marrow plasma cells from all of the patients with multiple myeloma, and median MFI was 47. The difference in MFI for RANKL expression of bone marrow plasma cells from controls and myeloma patients was highly significant (P < 0.0005). Myeloma patients with osteolytic bone lesions showed a significantly higher expression of RANKL (median MFI = 60; range, 16-2494) compared with patients without osteolysis (median MFI = 16; range, 6-229; P < 0.0005). CONCLUSIONS: These results show for the first time that the level of RANKL expression by myeloma cells correlates significantly with osteolytic bone disease. 相似文献
964.
Mycophenolate mofetil increases cytomegalovirus invasive organ disease in renal transplant patients 总被引:11,自引:0,他引:11
The impact of cytomegalovirus (CMV) infection post-transplantation is in part influenced by the degree of immunosuppression. While mycophenolate mofetil (MMF) does not increase the overall incidence of CMV infection, we have questioned whether or not it increases its severity. Using a case control study design in which 29 renal transplant patients developed CMV disease [17 (59%) of which received azathioprine (AZA) and 12 (41%) received MMF], increases in the frequency of organ involvement with CMV (58 vs. 18%; p = 0.03) and in the number of organs involved with CMV were noted in the MMF versus the AZA group (2.0 vs. 1.0; p = 0.015). These results indicate that the increased immunosuppressive activity of MMF impacts the morbidity of CMV infection, thus warranting the use of effective anti-CMV preventive regimens while patients are treated with MMF. 相似文献
965.
Wang A Holcslaw T Bashore TM Freed MI Miller D Rudnick MR Szerlip H Thames MD Davidson CJ Shusterman N Schwab SJ 《Kidney international》2000,57(4):1675-1680
BACKGROUND: Endothelin is a potent vasoconstrictor that has been implicated in the pathogenesis of radiocontrast nephrotoxicity. Endothelin antagonists may reduce the renal hemodynamic abnormalities following radiocontrast administration. METHODS: One hundred fifty-eight patients with chronic renal insufficiency [mean serum creatinine +/- SD = 2.7 +/- 1.0 mg/dL (242. 3 to +/- 92.8 micromol/L)] and undergoing cardiac angiography were randomized to receive either a mixed endothelin A and B receptor antagonist, SB 290670, or placebo. All patients received intravenous hydration with 0.45% saline before and after radiocontrast administration. Serum creatinine concentrations were measured at baseline, 24 hours, 48 hours, and 3 to 5 days after radiocontrast administration. The primary end point was the mean change in serum creatinine concentration from baseline at 48 hours; the secondary end point was the incidence of radiocontrast nephrotoxicity, defined as an increase in serum creatinine of > or =0.5 mg/dL (44 micromol/L) or > or = 25% from baseline within 48 hours of radiocontrast administration. RESULTS: The mean increase in serum creatinine 48 hours after angiography was higher in the SB 209670 group [0.7 +/- 0. 7 mg/dL (63.5 +/- 58.6 micromol/L)] than in the placebo group [0.4 +/- 0.6 mg/dL (33.6 +/- 55.1 micromol/L), P = 0.002]. The incidence of radiocontrast nephrotoxicity was also higher in the SB 209670 group (56%) compared with placebo (29%, P = 0.002). This negative effect of SB 209670 was apparent in both diabetic and nondiabetic patients. Adverse effects, especially hypotension or decreased blood pressure, were more common in the SB 209670 group. CONCLUSIONS: In patients with chronic renal insufficiency who were undergoing cardiac angiography, endothelin receptor antagonism with SB 209670 and intravenous hydration exacerbate radiocontrast nephrotoxicity compared with hydration alone. 相似文献
966.
967.
Mauro Calvani Claudia Alessandri Giuseppe Paolone Luciano Rosengard Antonino Di Caro David De Franco 《Pediatric allergy and immunology》1997,8(2):91-96
It is currently accepted that vinil infections may influence the development of atopy. In the present study we evaluated serum IgE levels as well as the prevalence of symptom-, indicative of utopic disease and EBV antibodies in 353 children aged from I month to 19 years. Antibodies against EBV were detected by immunofluorescence. IgE levels in serum were measured by en/. yme imimmoassay. Dividing ihe study population according to EBV seropositivity and age, we noted that the prevalence of high IgE levels (> 2 s. d.) was, in total, more frequent in the EBV negative (32. 9%) than in the positive subjects (27. 6%). Interestingly, this higher prevalence was found only in the groups aged under six, especially in the 7 to 29 month group, where it was statistically significant (p=0.037), whereas in the 6-19 year group the situation was reversed. Furthermore, selecting only the atopic children younger than 3 years of age with high IgE levels and clinical symptoms of atopy (wheezing and/or dermatitis) it was possible to demonstrate lower EBV seropositivity compared with the normal IgE controls for each group, even though these differences were not statistically significant. In conclusion, the results of our study suggest that, in our selected population, EBV infection in the first years of life is associated with a lower prevalence of high IgE levels. 相似文献
968.
969.
This report reviews the current theories on the deposition of inhaled particulates in the human nose. The inhalation of particulates represents a challenge to the upper respiratory tract. The concentration of airborne particulates and pollutants varies between occupational and nonoccupational exposure. Regional deposition of potentially hazardous inhaled material determines the local and systemic toxicity. In vitro experiments using casting and molding techniques with water dye models or laser Doppler anemometry indicate that nasal airflow is determined by the size of the nasal valve and the turbinates. The main airstream during inspiration passes through the lower nasal passage. Filtration capacity of the human nose can be expressed mathematically or experimentally. In vivo experiments applying monodisperse or polydisperse aerosols during single or multiple respiratory cycles have shown by using microscopic or laser-optic identification that particles larger than 3µm have a maximum deposition in the anterior part of the nose (nasal valve). Particles smaller than 3 µm and larger than 0.5 µm are filtered by the nasal mucosa and transported by cilia propulsion to the nasopharynx. The filtration for particles smaller than 0.5 µm is low. They seem to pass easily into the lower respiratory tract. This knowledge has an impact on nasal septal surgery and rhinoplasty. By influencing the structure of the nasal valve and the lower turbinates, the filtration capacity of the nose can be significantly decreased. 相似文献
970.