全文获取类型
收费全文 | 2325634篇 |
免费 | 175431篇 |
国内免费 | 5612篇 |
专业分类
耳鼻咽喉 | 30422篇 |
儿科学 | 75805篇 |
妇产科学 | 64674篇 |
基础医学 | 344357篇 |
口腔科学 | 64936篇 |
临床医学 | 223251篇 |
内科学 | 448169篇 |
皮肤病学 | 48352篇 |
神经病学 | 191424篇 |
特种医学 | 84922篇 |
外国民族医学 | 603篇 |
外科学 | 325383篇 |
综合类 | 50441篇 |
现状与发展 | 4篇 |
一般理论 | 978篇 |
预防医学 | 197983篇 |
眼科学 | 52111篇 |
药学 | 171475篇 |
12篇 | |
中国医学 | 4784篇 |
肿瘤学 | 126591篇 |
出版年
2019年 | 19165篇 |
2018年 | 26288篇 |
2017年 | 20030篇 |
2016年 | 21752篇 |
2015年 | 24953篇 |
2014年 | 34638篇 |
2013年 | 53511篇 |
2012年 | 73082篇 |
2011年 | 77798篇 |
2010年 | 45206篇 |
2009年 | 42511篇 |
2008年 | 72056篇 |
2007年 | 76733篇 |
2006年 | 76460篇 |
2005年 | 74362篇 |
2004年 | 71206篇 |
2003年 | 67966篇 |
2002年 | 65779篇 |
2001年 | 101830篇 |
2000年 | 104434篇 |
1999年 | 87990篇 |
1998年 | 25225篇 |
1997年 | 22932篇 |
1996年 | 22983篇 |
1995年 | 21808篇 |
1994年 | 20367篇 |
1993年 | 19088篇 |
1992年 | 70287篇 |
1991年 | 69220篇 |
1990年 | 67134篇 |
1989年 | 64244篇 |
1988年 | 59549篇 |
1987年 | 58395篇 |
1986年 | 55698篇 |
1985年 | 53106篇 |
1984年 | 40135篇 |
1983年 | 34783篇 |
1982年 | 20863篇 |
1979年 | 37553篇 |
1978年 | 27224篇 |
1977年 | 22465篇 |
1976年 | 21546篇 |
1975年 | 22591篇 |
1974年 | 27611篇 |
1973年 | 27200篇 |
1972年 | 25370篇 |
1971年 | 23729篇 |
1970年 | 22208篇 |
1969年 | 20614篇 |
1968年 | 19441篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Our study was intended to determine whether power Doppler sonography can be considered superior to color Doppler technique in depiction of normal orbital vasculature. Ten healthy volunteers (20 eyes) were examined with a 10 MHz linear probe; each orbital vessel was recorded with both color and power Doppler methods; the images were reviewed independently by all the observers, who agreed that power Doppler clearly is superior to color Doppler technique for evaluation of the anatomy of orbital arteries and veins. 相似文献
993.
J. M. Johnston P. Grondziowski R. M. Windisch R. A. Eder L. Lytle 《Acta diabetologica》1995,32(4):213-216
A feasibility study was undertaken to evaluate laboratory phlebotomists performing bedside glucose monitoring (BGM) over a
3-month period on a medical and surgical floor. Specific questions included: feasibility of providing testing on a 24-h basis,
accuracy, appropriate utilization, effect on patient care, and an analysis of cost. In all, 1975 tests were performed on 114
patients. BGM results were within 15% of the laboratory's result 97% of the time. Patient and physician satisfaction was high.
Although the cost of BGM is slightly higher than a laboratory glucose test, its use appeared to reduce the length of hospital
stay by 0.47 days. Practical information on initiating a highly successful BGM program is provided. 相似文献
994.
Recent reports suggest that oxygen radical-induced lipid peroxidation plays a role in the retrograde degeneration of motor neurons following facial nerve axotomy in the neonatal rat. The purpose of the present study was to explore this notion further by testing the neuroprotective properties of two novel brain-penetrating, lipid peroxidation inhibitors, U-101033E and U-104067F, in this model of neuronal degeneration. In Experiment 1, 14-day-old rats were pretreated with 3, 10, or 30 mg/kg U-101033E (po) 10 min before right facial nerve axotomy (Day 0) and then posttreated once a day from Day 1 to Day 6, and once every other day from Day 8 to Day 21. Rats were sacrificed 21 days postaxotomy and surviving cholinergic cell bodies were identified using choline acetyltransferase immunocytochemistry. Both 10 and 30 mg/kg U-101033E significantly enhanced motor neuron survival, with survival rates of 65.9–88.9% being noted in comparison to 51.7–62% survival in vehicle controls (P ≤ 0.05). Experiment 2 demonstrated a significant neuroprotective effect of 10 and 30 mg/kg U-104067F using the same dosing schedule. Experiment 3 was designed to test whether shorter periods of drug exposure (e.g., 5 or 7 days) would be sufficient to preserve motor neurons in rats treated with 10 mg/kg U-101033E. The results suggested that as little as 5 days of drug treatment is sufficient to enhance motor neuron survival. Finally, Experiment 4 demonstrated an 18–19% increase in motor neuron survival in rats treated with 10 and 30 mg/kg U-104067F for 5 consecutive days postaxotomy. Taken together, the attenuation of motor neuron degeneration by the two pyrrolopyrimidine lipid peroxidation inhibitors, U-101033E and U-104067F, lends support to the notion that lipid peroxidation contributes to the pathogenesis of axotomy-induced neurodegeneration. 相似文献
995.
The effect of oxygen free radicals on calcium current and dihydropyridine binding sites in guinea-pig ventricular myocytes. 下载免费PDF全文
L. Guerra E. Cerbai S. Gessi P. A. Borea A. Mugelli 《British journal of pharmacology》1996,118(5):1278-1284
1. We used electrophysiological and binding techniques to determine the effects of oxygen free radicals (OFRs) generated by dihydroxyfumaric acid (DHF, 5 mM) on calcium current and dihydropyridine binding sites in guinea-pig isolated ventricular myocytes. 2. Binding of [3H]-PN200-110 to isolated ventricular myocytes revealed one population of binding sites with a KD of 0.11 +/- 0.01 nM and Bmax of 139.1 +/- 6.9 fmol mg-1 protein (n = 24). After 15 min of exposure to DHF, the density, but not the affinity of [3H]-PN200-110 binding sites was significantly (P < 0.01) reduced to 35% of the control value (Bmax = 49.4 +/- 3.7 fmol mg-1 protein, KD = 0.11 +/- 0.01 nM, n = 15). In the presence of superoxide dismutase (SOD) and catalase (CAT) the reduction in [3H]-PN200-110 binding sites was almost completely prevented (Bmax = 120.5 +/- 7.4 in control, n = 4 and 98.8 +/- 7.4 fmol mg-1 protein in DHF plus SOD and CAT, n = 4). KD values were not modified (0.08 +/- 0.01 in control and 0.09 +/- 0.01 nM in DHF plus SOD and CAT). 3. The time-course of the reduction of [3H]-PN200-110 binding sites by OFRs was paralleled by the decrease in L-type calcium current (Ica,L) measured in patch-clamped guinea-pig ventricular myocytes either in the absence or in the presence of EGTA in the patch pipette. In the former conditions OFRs induced the appearance of calcium-dependent alterations, i.e. the transient inward current, within 10 min. After 30 min of incubation with DHF, [3H]-PN200-110 binding sites were reduced to 25% of the control value. 4. In myocytes incubated with the antilipoperoxidant agent, butylated hydroxytoluene (BHT, 50 microM), the decrease in [3H]-PN200-110 binding sites caused by DHF was partially prevented (Bmax values after 30 min exposure to DHF were 55.5 +/- 1.9 and 23.7 +/- 5.9 fmol mg-1 protein in the presence and in the absence of BHT respectively, P < 0.05). BHT did not affect the decrease in [3H]-PN200-110 binding sites during the first 15 min of exposure to DHF, but was able to prevent completely the further decrease occurring during the following 15 min of incubation with OFRs. 5. Our results demonstrate that the OFR-induced decrease in calcium current is associated with a reduction in DHP binding sites. The decrease in calcium current and in calcium channels may be implicated in the mechanical dysfunction associated with oxidative stress. 相似文献
996.
997.
W. Hughes A. Barr B. C. Dow† E. A. C. Follett † J. A. J. Barbara‡ 《Transfusion medicine (Oxford, England)》1995,5(3):225-230
SUMMARY. Samples from 1828 donations were screened for anti-HBc at seven sites in the UK using kits supplied by 10 manufacturers. Only 10 (0.55%) donations were considered to have true anti-HBc reactivity and these were detected by all 10 kits. Additional markers of HBV infection were found in nine of these 10 donations. Additional reactives were found by all kits, the number ranging from 1 to 43.
In the four more specific kits, the 10 true reactives were clearly distinguished from the 'false reactives' by the strength of the reaction. It is concluded that the reliance on a single ELISA test for anti-HBc diagnosis is unwise. The use of a second test known to be more specific than the screening ELISA is recommended. 相似文献
In the four more specific kits, the 10 true reactives were clearly distinguished from the 'false reactives' by the strength of the reaction. It is concluded that the reliance on a single ELISA test for anti-HBc diagnosis is unwise. The use of a second test known to be more specific than the screening ELISA is recommended. 相似文献
998.
Data on 232 members of a single pedigree, descended from two pairs of original parents, were made available to the participants of Genetic Analysis Workshop 8 (GAW8). In addition to information concerning age and sex, measurements for 10 quantitative traits and genotypes at 22 polymorphic marker loci were also provided for a subset of 193 of these family members. © 1993 Wiley-Liss, Inc. 相似文献
999.
B L Bower D Picus M E Hicks M D Darcy E S Rollins M A Kleinhoffer P J Weyman 《Journal of vascular and interventional radiology : JVIR》1990,1(1):107-112
Retained biliary stones remain a common clinical problem in patients after surgery. Since 1984, the authors have used choledochoscopy in the treatment of suspected retained biliary stones in 75 patients. These procedures were performed in the radiology department with use of local anesthesia supplemented by an intravenously administered sedative and analgesic. A 15-F flexible fiberoptic choledochoscope was used. Fifty-one of the 75 patients were treated as outpatients. Treatment was successful in 74 of 75 patients; in one patient, intrahepatic stones were not completely removed. Electrohydraulic lithotripsy was used to fragment calculi in 11 patients (15%). Biopsies were performed in four patients (5%). Five minor complications occurred; three required overnight admission. Choledochoscopic-assisted removal of retained biliary calculi is a highly effective and safe procedure. Advantages over standard fluoroscopic stone removal include the ability to directly visualize and fragment adherent or impacted stones and visualize noncalculous filling defects, such as air bubbles, mucus, and biliary tumors. 相似文献
1000.