全文获取类型
收费全文 | 1280768篇 |
免费 | 100295篇 |
国内免费 | 1992篇 |
专业分类
耳鼻咽喉 | 18448篇 |
儿科学 | 44530篇 |
妇产科学 | 35096篇 |
基础医学 | 182785篇 |
口腔科学 | 33690篇 |
临床医学 | 111786篇 |
内科学 | 258911篇 |
皮肤病学 | 28118篇 |
神经病学 | 100699篇 |
特种医学 | 51344篇 |
外国民族医学 | 660篇 |
外科学 | 196853篇 |
综合类 | 27206篇 |
现状与发展 | 1篇 |
一般理论 | 384篇 |
预防医学 | 96126篇 |
眼科学 | 28003篇 |
药学 | 95115篇 |
2篇 | |
中国医学 | 2422篇 |
肿瘤学 | 70876篇 |
出版年
2018年 | 13197篇 |
2017年 | 10022篇 |
2016年 | 10958篇 |
2015年 | 12451篇 |
2014年 | 17258篇 |
2013年 | 26351篇 |
2012年 | 36178篇 |
2011年 | 38230篇 |
2010年 | 22898篇 |
2009年 | 21927篇 |
2008年 | 36786篇 |
2007年 | 39419篇 |
2006年 | 39661篇 |
2005年 | 38614篇 |
2004年 | 37760篇 |
2003年 | 36620篇 |
2002年 | 35987篇 |
2001年 | 64148篇 |
2000年 | 66642篇 |
1999年 | 56535篇 |
1998年 | 15192篇 |
1997年 | 13814篇 |
1996年 | 14238篇 |
1995年 | 13494篇 |
1994年 | 12811篇 |
1993年 | 11852篇 |
1992年 | 44635篇 |
1991年 | 43569篇 |
1990年 | 42320篇 |
1989年 | 40209篇 |
1988年 | 36989篇 |
1987年 | 36323篇 |
1986年 | 33692篇 |
1985年 | 32350篇 |
1984年 | 24201篇 |
1983年 | 20319篇 |
1982年 | 11765篇 |
1981年 | 10721篇 |
1980年 | 9543篇 |
1979年 | 21382篇 |
1978年 | 14854篇 |
1977年 | 12566篇 |
1976年 | 11711篇 |
1975年 | 12649篇 |
1974年 | 14691篇 |
1973年 | 14140篇 |
1972年 | 12973篇 |
1971年 | 11749篇 |
1970年 | 11070篇 |
1969年 | 10038篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A. PESONEN R. SUOJARANTA-YLINEN E. HAMMARÉN P. TARKKILA T. SEPPÄLÄ P. H. ROSENBERG 《Acta anaesthesiologica Scandinavica》2009,53(1):101-108
Background: In elderly patients, opioids may cause prominent postoperative sedation and respiratory depression. We evaluated the influence of age on the effects of opioids and plasma concentrations of fentanyl and oxycodone in cardiac surgery patients.
Methods: Thirty (≥75 years, gender M9/F21) and 20 (≤60 years, gender M20/F0) patients scheduled to undergo cardiac surgery. A standard anesthesia with fentanyl as an opioid was used. Fentanyl plasma concentrations were measured at the end of surgery and 2 h later. After tracheal extubation, when the pain intensity was at least moderate, blood samples for fentanyl and oxycodone plasma concentration measurements were taken. Thereafter, oxycodone hydrochloride 0.05 mg/kg i.v. was administered. After 15 and 45 min, pain intensity, sedation and oxycodone plasma concentration were determined. This test protocol was repeated twice.
Results: The elderly had a higher plasma concentration of fentanyl at the end of surgery than younger patients (5.7±2.2 vs. 3.8±1.2 ng/ml, P =0.001). The plasma concentrations of oxycodone were comparable between the groups. The interval between the second and the third oxycodone dose was longer in the elderly patients ( P =0.036). Pain intensity on the verbal rating scale was lower at the 45-min assessment point after all three oxycodone test doses ( P =0.008) and sedation scores were significantly higher after the third dose in the elderly patients ( P =0.035).
Conclusions: In elderly patients, the plasma concentration of fentanyl was higher but plasma levels of oxycodone were at a similar level compared with middle-aged patients. However, the elderly patients had less pain and were more sedated after doses of oxycodone. 相似文献
Methods: Thirty (≥75 years, gender M9/F21) and 20 (≤60 years, gender M20/F0) patients scheduled to undergo cardiac surgery. A standard anesthesia with fentanyl as an opioid was used. Fentanyl plasma concentrations were measured at the end of surgery and 2 h later. After tracheal extubation, when the pain intensity was at least moderate, blood samples for fentanyl and oxycodone plasma concentration measurements were taken. Thereafter, oxycodone hydrochloride 0.05 mg/kg i.v. was administered. After 15 and 45 min, pain intensity, sedation and oxycodone plasma concentration were determined. This test protocol was repeated twice.
Results: The elderly had a higher plasma concentration of fentanyl at the end of surgery than younger patients (5.7±2.2 vs. 3.8±1.2 ng/ml, P =0.001). The plasma concentrations of oxycodone were comparable between the groups. The interval between the second and the third oxycodone dose was longer in the elderly patients ( P =0.036). Pain intensity on the verbal rating scale was lower at the 45-min assessment point after all three oxycodone test doses ( P =0.008) and sedation scores were significantly higher after the third dose in the elderly patients ( P =0.035).
Conclusions: In elderly patients, the plasma concentration of fentanyl was higher but plasma levels of oxycodone were at a similar level compared with middle-aged patients. However, the elderly patients had less pain and were more sedated after doses of oxycodone. 相似文献
992.
Michael Bohnsack D.B. Saris J. Vanlauwe F. Almqvist J. Victor J. Bellemans R. Verdonk F.P. Luyten 《Sport》2009,25(2):137-138
993.
994.
PTH has diverse effects on bone metabolism: anabolic when given intermittently, catabolic when given continuously. The cellular
mechanisms underlying the varying target cell response are not clear yet. PTH induces RGS-2, a member of the Regulator of
G-protein Signaling protein family, via cAMP/PKA, and inactivates PKC-mediated signaling. To investigate intracellular signaling
pathways with different PTH concentration-time patterns, we treated UMR 106-01 osteoblast-like cells in a perfusion system.
PTH was administered intermittently (4 min/h, 10−7 M) or continuously at an equivalent cumulative dose (6.6 × 10−9 M). cAMP was measured using radioimmunoassay, mRNA levels using real-time rtPCR and ribonuclease protection assay, and protein
levels using Western immunoblotting. A single PTH pulse transiently increased cAMP levels by 2000% ± 1200%. In contrast to
continuous PTH exposure, cAMP induction remained unchanged with intermittent PTH, ruling out desensitization of the PTH receptor.
In continuously perfused cells, RGS-2 abundance was three to five times higher than in cells intermittently exposed to PTH
for up to 12 h. MKP-1 and -3 were significantly less induced with pulsatile PTH; exposure-mode-dependent differences in MMP-13
and IGFBP-5 were small. Pulsatile but not continuous PTH administration prevents PTHrP receptor desensitization and accumulation
of RGS-2 in osteoblasts, which should preserve PKC-dependent signaling. 相似文献
995.
996.
997.
998.
999.
1000.