全文获取类型
收费全文 | 2300篇 |
免费 | 138篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 57篇 |
妇产科学 | 47篇 |
基础医学 | 274篇 |
口腔科学 | 21篇 |
临床医学 | 248篇 |
内科学 | 524篇 |
皮肤病学 | 64篇 |
神经病学 | 130篇 |
特种医学 | 164篇 |
外科学 | 297篇 |
综合类 | 19篇 |
预防医学 | 164篇 |
眼科学 | 33篇 |
药学 | 173篇 |
中国医学 | 1篇 |
肿瘤学 | 223篇 |
出版年
2021年 | 21篇 |
2019年 | 21篇 |
2018年 | 31篇 |
2017年 | 19篇 |
2016年 | 20篇 |
2015年 | 22篇 |
2014年 | 50篇 |
2013年 | 63篇 |
2012年 | 106篇 |
2011年 | 90篇 |
2010年 | 69篇 |
2009年 | 63篇 |
2008年 | 91篇 |
2007年 | 87篇 |
2006年 | 71篇 |
2005年 | 77篇 |
2004年 | 77篇 |
2003年 | 87篇 |
2002年 | 59篇 |
2001年 | 79篇 |
2000年 | 58篇 |
1999年 | 65篇 |
1998年 | 42篇 |
1997年 | 37篇 |
1996年 | 29篇 |
1995年 | 26篇 |
1994年 | 22篇 |
1993年 | 26篇 |
1992年 | 68篇 |
1991年 | 58篇 |
1990年 | 51篇 |
1989年 | 70篇 |
1988年 | 55篇 |
1987年 | 37篇 |
1986年 | 45篇 |
1985年 | 47篇 |
1984年 | 41篇 |
1983年 | 30篇 |
1982年 | 23篇 |
1981年 | 22篇 |
1980年 | 26篇 |
1979年 | 51篇 |
1978年 | 25篇 |
1977年 | 30篇 |
1976年 | 28篇 |
1974年 | 18篇 |
1973年 | 19篇 |
1972年 | 19篇 |
1971年 | 21篇 |
1970年 | 15篇 |
排序方式: 共有2449条查询结果,搜索用时 15 毫秒
1.
2.
Localized osteolysis in stable, non-septic total hip replacement 总被引:6,自引:0,他引:6
M J Jasty W E Floyd A L Schiller S R Goldring W H Harris 《The Journal of bone and joint surgery. American volume》1986,68(6):912-919
We are reporting four cases of extensive, localized bone resorption adjacent to a rigidly anchored, cemented total hip replacement. None of these hips showed evidence of infection on clinical, bacteriological, or pathological evaluation. The tissue from the regions of osteolysis showed sheets of macrophages and foreign-body giant cells invading the femoral cortices. Abundant methylmethacrylate particulate debris was present in the tissues, but polyethylene wear debris was absent. The histological appearance of this tissue resembled that reported about loosened total hip implants with the exception of the synovial-like layer at the cement surface. The cases reported here show that aggressive bone lysis may occur around stable cemented total hip arthroplasties without the presence of sepsis or malignant disease. 相似文献
3.
ALBERTO Q FARIAS LUCIANA L GONÇALVES EDUARDO LR CANÇADO ANTONIO C SEGURO SILVIA B CAMPOS CLARICE P ABRANTES-LEMOS FLAIR J CARRILHO 《Journal of gastroenterology and hepatology》2006,20(1):147-152
Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients. 相似文献
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients. 相似文献
4.
5.
Focal glomerulosclerosis in the remnant kidney model--an inflammatory disease mediated by cytokines 总被引:7,自引:0,他引:7
BACKGROUND: The mechanism of progression of established renal disease
remains unclear. While a low protein diet slows this progression, the role
of cytokines in this process has been little investigated. METHODS: We
investigated cytokine expression by Northern blot and immunohistochemistry
in two groups of 5/6 nephrectomized rats (5/6 Nx) fed a normal (24%) or low
(6%) protein diet and compared them with sham operated controls. RESULTS:
The rats on 6% protein diet had significantly less focal glomerulosclerosis
(FGS) (17.4 +/- 4.4 vs 27.4 +/- 8.8%, P < 0.05) and global sclerosis
(GGS) after 7 weeks (0.4 +/- 0.8 vs 3.5 +/- 2.1% of glomeruli P < 0.05).
Both experimental groups showed three times control levels of MCP-I
expression after 2 weeks. However in the 5/6 Nx 6% protein group the
expression decreased at 4 weeks (1.5 times controls) and reached control
levels after 7 weeks. In contrast, the 5/6 Nx 24% protein group exhibited a
further marked increase after 4 weeks (5.6 times controls) and was still
two-fold higher after 7 weeks. TGF-beta expression was modestly but
consistently increased at all time points (120-160% of controls), with no
difference between the two study groups. Neither IL-1 beta or TNF-alpha was
detectable at any time. Immunohistochemistry demonstrated TGF-beta
intracellularly in distal tubular cells in both experimental and control
animals, while MCP-1 protein was found in the area of FGS and in the apical
pole of distal tubular cells in both experimental groups. Glomerular and
interstitial ED1 positive cells were significantly increased after four
weeks in the 5/6 Nx 24% protein group (P < 0.05). CONCLUSIONS: A
'mechanical' injury to the kidney clearly results in an inflammatory
response associated with the upregulation of MCP-1. A low protein diet
modulates the expression of MCP-1 and improves the morphological sequelae
seen after renal ablation.
相似文献
6.
7.
Amr E Abbas F David Fortuin Bhavesh Patel Carlos A Moreno Nelson B Schiller Steven J Lester 《Journal of the American Society of Echocardiography》2004,17(8):834-838
BACKGROUND: Systemic vascular resistance (SVR) is an integral therapeutic component of patients with heart failure and shock. We hypothesized that the ratio of the peak mitral regurgitant velocity (MRV) (m/s) to left ventricular outflow time-velocity integral (TVI(LVOT)) (cm) by Doppler would provide a noninvasive correlate of SVR. METHODS: SVR was correlated to MRV/TVI(LVOT) in 33 patients undergoing right heart catheterization. Receiver operating characteristic curves were generated to determine the best-balanced sensitivity and specificity to identify SVR > 14 Wood units (WU) and <10 WU. RESULTS: MRV/TVI(LVOT) correlated well with SVR (r = 0.842, 95% confidence interval 0.7-0.92, P <.001, Y = 0.459 + 49.397*X). By receiver operating characteristics, MRV/TVI(LVOT) > 0.27 had a 70% sensitivity and a 77% specificity to identify SVR > 14 WU. MRV/TVI(LVOT) < 0.2 had a 92% sensitivity and a 88% specificity to identify SVR < 10 WU. CONCLUSION: Doppler echocardiography provides a reliable noninvasive assessment of SVR. 相似文献
8.
Ohne Zusammenfassung 相似文献
9.
MGC Hendriks P Dogterom JT Ebels B Oosterhuis LR Geertsema T Hulot G Bianchetti and JHG Jonkman 《Fundamental & clinical pharmacology》1998,12(5):559-565
Summary— In the present study we have compared the steady state biopharmaceutic characteristics of four diltiazem once daily controlled release capsules: Mono-Tildiem LP 300® (300 mg), Adizem® XL (300 mg)1, Cardizem® (300 mg) and Dilacor® (240 mg). Sixteen healthy male volunteers (aged 22.9 ± 3.3 years, range 19–31 years) completed an open label, multiple oral dose, randomized, four-period crossover study without a washout period in between. The volunteers received each diltiazem formulation once daily for four days. Trough diltiazem and metabolites plasma concentrations were determined on days 3 and 4. The 24-h plasma concentration-time profiles were assessed after the dose on day 4 of each period. The following steady state pharmacokinetic parameters for diltiazem were calculated: the minimum plasma concentration (cmin), the maximum plasma concentration (cmax), the time to reach that concentration (tmax), the time interval during which the plasma concentration exceeds 50% of cmax (t50), the area under the plasma concentration-time curve (AUC72–96) and the peak-to-trough fluctuation (PTF). For the metabolites of diltiazem, N-mono-desmethyl-diltiazem (NDM) and desacetyldiltiazem (DAD), AUC72–96 (AUCNDM and AUCDAD) and the ratio metabolite/parent compound were calculated. Steady state was achieved on day 3. Except one, all controlled release formulations have satisfactory controlled release properties allowing once daily administration. However, significant (P < 0.05) differences were found between the pharmacokinetic characteristics which do not allow exchange of the various formulations. Concentrations well below 50 ng·mL-1 in the morning hours were observed for Dilacor® (240 mg) and Adizem® XL (300 mg), which could be a disadvantage of these formulations as it is well-known that ischaemic events occur at a higher rate during that part of the day. The plasma concentration profiles of NDM and DAD, the major circulating metabolites, parallel the plasma concentration profiles for the parent compound. From a clinical point of view, all treatments were well tolerated. 相似文献
10.
Brigitte Schiller Chun He David J. Salant Alice Lim Jessy J. Alexander Richard J. Quigg 《The Journal of experimental medicine》1998,188(7):1353-1358
Crry (complement receptor 1–related protein/gene y) is a key cellular complement regulator in rodents. It is also present in Fx1A, the renal tubular preparation used to immunize rats to induce active Heymann nephritis (HN), a model of membranous nephropathy. We hypothesized that rats immunized with anti-Fx1A develop autoantibodies (auto-Abs) to Crry as well as to the megalin-containing HN antigenic complex, and that anti-Crry Abs promote the development of injury in HN by neutralizing the complement regulatory activity of Crry. Rats immunized with Fx1A lacking Crry remained free of proteinuria and glomerular deposits of C3 during a 10-wk follow-up despite typical granular immunoglobulin (Ig)G deposits in glomeruli. Anti-Fx1A auto-Abs were present in their sera at levels that were not different from sera pooled from proteinuric rats with HN induced with nephritogenic Fx1A. Passive administration of sheep anti-Crry Abs to rats immunized with Crry-deficient Fx1A led to proteinuria and glomerular C3 deposition, which were not seen in such rats injected with preimmune IgG, nor in rats with collagen-induced arthritis injected with anti-Crry IgG. To directly examine the role of Crry in HN, rats were immunized with Crry-deficient Fx1A reconstituted with rCrry. This led to typical HN, with 8 out of 15 rats developing proteinuria within 14 wk. Moreover, the extent of glomerular C3 deposition correlated with proteinuria, and anti-Crry Abs were present in glomerular eluates. Thus, Crry is a key nephritogenic immunogen in Fx1A. Formation of neutralizing auto-Abs to Crry impairs its function, leading to unrestricted complement activation by Abs reactive with the HN antigenic complex on the epithelial cell surface. 相似文献