全文获取类型
收费全文 | 21941篇 |
免费 | 1404篇 |
国内免费 | 886篇 |
专业分类
耳鼻咽喉 | 82篇 |
儿科学 | 304篇 |
妇产科学 | 69篇 |
基础医学 | 2346篇 |
口腔科学 | 1062篇 |
临床医学 | 1577篇 |
内科学 | 2487篇 |
皮肤病学 | 476篇 |
神经病学 | 1228篇 |
特种医学 | 508篇 |
外国民族医学 | 1篇 |
外科学 | 1598篇 |
综合类 | 2857篇 |
现状与发展 | 3篇 |
预防医学 | 1050篇 |
眼科学 | 367篇 |
药学 | 6744篇 |
25篇 | |
中国医学 | 1020篇 |
肿瘤学 | 427篇 |
出版年
2023年 | 194篇 |
2022年 | 493篇 |
2021年 | 723篇 |
2020年 | 621篇 |
2019年 | 582篇 |
2018年 | 584篇 |
2017年 | 568篇 |
2016年 | 620篇 |
2015年 | 578篇 |
2014年 | 1339篇 |
2013年 | 1536篇 |
2012年 | 1328篇 |
2011年 | 1377篇 |
2010年 | 1163篇 |
2009年 | 1033篇 |
2008年 | 981篇 |
2007年 | 997篇 |
2006年 | 947篇 |
2005年 | 811篇 |
2004年 | 762篇 |
2003年 | 675篇 |
2002年 | 569篇 |
2001年 | 473篇 |
2000年 | 387篇 |
1999年 | 349篇 |
1998年 | 311篇 |
1997年 | 301篇 |
1996年 | 299篇 |
1995年 | 255篇 |
1994年 | 225篇 |
1993年 | 198篇 |
1992年 | 177篇 |
1991年 | 179篇 |
1990年 | 160篇 |
1989年 | 165篇 |
1988年 | 152篇 |
1987年 | 120篇 |
1986年 | 124篇 |
1985年 | 328篇 |
1984年 | 261篇 |
1983年 | 236篇 |
1982年 | 220篇 |
1981年 | 192篇 |
1980年 | 151篇 |
1979年 | 125篇 |
1978年 | 77篇 |
1977年 | 61篇 |
1976年 | 54篇 |
1975年 | 51篇 |
1973年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
通过实验室和口腔科临床观察表明:TD清洗消毒剂(氯化磷酸三钠)对金黄色葡萄球菌、绿脓杆菌和枯草杆菌黑色变种的平均杀菌率为100.0%,对口腔科器械消毒无菌率为100%,对被HBsAg阳性血清污染的器械浸泡30分钟转阴率为98.1%。其消毒效果优于新洁尔灭,与戊二醛相同。在口腔科使用两年,未见金属器械有锈斑生成。 相似文献
132.
考察了头孢哌酮钠在醋酸钠平衡液中的稳定性。二药配伍后,置室温(25℃)及37℃水浴中,6h内溶液无颜色改变,亦无沉淀、气体产生,头孢哌酮钠均在初始浓度的95%以上。 相似文献
133.
目的:观察丙戊酸钠与尼莫地平治疗偏头痛的疗效有否差别。方法:偏头痛129例,随机分为丙戊酸钠治疗组66例(男性17例,女性49例;年龄25±s7a),丙戊酸钠开始剂量为0.2g,po,tid,以后根据发作频率及程度逐渐增量,最大量1.4g/d,共用3mo;尼莫地平对照组63例(男性18例,女性45例,年龄27±6a),尼莫地平30mg,po,tid,共用3mo。结果:丙戊酸钠组总有效率为83%。尼莫地平组为85%,2组无明显差异(P>0.05).未见严重不良反应。结论:丙戊酸钠与尼莫地平治疗偏头痛安全有效、疗效相似。 相似文献
134.
Masato Sakamoto Koichiro Takeshige Hisataka Yasui Kouichi Tokunaga 《Surgery today》1998,28(5):522-528
(Received for publication on Sept. 12, 1996; accepted on May 12, 1997) 相似文献
135.
A case of deliberate ingestion of clothes washing liquid and fabric conditioner is described. Tracheal intubation and controlled ventilation became necessary because of respiratory muscle dysfunction associated with hypocalcaemia. We suggest that the phosphate component of the clothes washing liquid was responsible for the dramatic metabolic upset and subsequent need for admission to the Intensive Care Unit. 相似文献
136.
Brett Claire M. Washington Carla B. Ott Ronda J. Gutierrez Marcelo M. Giacomini Kathleen M. 《Pharmaceutical research》1993,10(3):423-426
The therapeutic efficacy of nucleosides and nucleoside analogues as antitumor, antiviral, antiparasitic, and antiarrhythmic agents has been well documented. Pharmacokinetic studies suggest that many of these compounds are actively transported in the kidney. The goal of this study was to determine if therapeutically relevant nucleosides or analogues interact with the recently characterized Na+-driven nucleoside transport system of the brush border membrane of the human kidney. Brush border membrane vesicles (BBMV) were prepared from human kidney by divalent cation precipitation and differential centrifugation. The initial Na+-driven 3H-uridine uptake into vesicles was determined by rapid filtration. The effect of several naturally occurring nucleosides (cytidine, thymidine, adenosine), a pyrimidine base (uracil), a nucleotide (UMP), and several synthetic nucleoside analogues [zidovudine (AZT), cytarabine (Ara-C), and dideoxycytidine (ddC)] on Na+–uridine transport was determined. At a concentration of 100 µM the naturally occurring nucleosides, uracil, and UMP significantly inhibited Na+-uridine transport, whereas the three synthetic nucleoside analogues did not. Adenosine competitively inhibited Na+-uridine uptake with a K
i of 26.4 µM (determined by constructing a Dixon plot). These data suggest that naturally occurring nucleosides are substrates of the Na+–nucleoside transport system in the renal brush border membrane, whereas synthetic nucleoside analogues with modifications on the ribose ring are not. The K
i of adenosine is higher than clinically observed concentrations and suggests that the system may play a physiologic role in the disposition of this nucleoside. 相似文献
137.
A. Y. S. Chan P. Poon E. L. P. Chan S. L. M. Fung Professor R. Swaminathan 《Osteoporosis international》1993,3(6):341-344
The effect of high sodium intake on bone mineral content of rats fed a normal (0.6% Ca) or a low (0.02% Ca) calcium diet was studied. Rats on a normal calcium diet given 1.8% sodium chloride to drink showed persistent and significant hypercalciuria and subnormal bone mineral content. Total calcium content of femur was significantly lower after 4 months (p<0.02) and 12 months (p<0.001). In rats maintained on a low calcium diet (0.02% Ca), a high sodium diet for 8 weeks caused a significant loss of calcium in bone similar to that seen in animals fed a normal calcium diet for 4 months. We conclude that high sodium intake reduces bone mineral content, especially if the diet is low in calcium. 相似文献
138.
Aspirin has antisecretory and ulcerogenic properties in the gastrointestinal tract. The aim of this study was to determine the effects of acetylsalicylic acid (ASA) on the electrical and mechanical activity of the ileum in anesthetized New Zealand White rabbits. Ileal electromechanical activity was recorded from serosal electrodes and a miniature intraluminal balloon. Thirty minutes after injection of ASA (30, 60 and 100 mg/kg intravenous) significant and dose-dependent increases in the percentage of slow waves with action potentials were observed when compared with saline-injected animals. The onset of action potentials correlated with phasic increases in intraluminal pressure, indicating the onset of circular muscle contractions. Injection of 15 mg/kg ASA, sodium salicylate (100 mg/kg intravenous) or saline had no effect on baseline action potential activity. Prostaglandin E
2 (PGE
2)(5 and 10 g/kg intravenous) significantly increased slow-wave frequency and decreased ASA-induced action potential activity. This study demonstrates that (1) ASA, but not sodium salicylate, stimulates phasic ileal action potential and contractile activity and (2) in ASA-treated animals, PGE
2
produces differential effects on in vivoslow-wave frequency and action potential activity. 相似文献
139.
Robert H. Smallwood George W. Mihaly Richard A. Smallwood Denis J. Morgan 《Journal of pharmacokinetics and pharmacodynamics》1988,16(5):529-542
For substances eliminated from blood by the liver, the effect of a change in unbound fraction of drug (fu
b
)on steady state total (C
b
)and unbound (Cu
b
)blood concentrations has hitherto only been considered for the two limiting cases, i.e., at the upper and lower extremes of hepatic intrinsic clearance (CL
int
).For a substance of very low CL
int
,if fu
b
changes, C
t
will change and Cu
b
will remain constant, whereas if CL
int
isvery high, Cu
b
will change and C
b
will remain constant.The present study defines the effects of a change in fu
b
on C
b
and Cu
b
over the whole CL
int
range. Computer simulations were undertaken which predicted that, for a given change in fu
b
,absolute and relative changes in C
b
would decreasenonlinearly with increasing CL
int, twhile the relative change in Cu
b would increasewith CL
int
.The absolute change in Cub
would be independent of CL
int
.Significant changes in Cb and Cu
b would be observed at intermediate values of CL
int not just at the high and low extremes. These theoretical predictions were investigated experimentally in the isolated perfused rat liver by examining the effects of a change in fu
b of sodium taurocholate a substance with intermediate CL
int
(such that at fu
b
=0.27,hepatic extraction ratio=0.71) induced by concurrent administration of sodium oleate. Sodium 24-
14
C-taurocholate (specific activity 52 Ci/mmol) was infused into the reservoir in a recycling system at 30 mol/hr for 105 min (n=6). At 45 min a bolus dose of sodium oleate (50 mmol) was administered to the reservoir, followed by a constant infusion of 143 mmol/hr for 1 hr. Following the administration of oleate, taurocholate fu
b fell promptly by 55% (0.27–0.12). There was a relative increase of taurocholate C
b of 22.7% and a relative decrease in Cu
b of 45.4%, in accordance with the simulations (p<0.05). We conclude that important changes in unbound steady-state concentration, the pharmacologically active moiety, can occur upon changes in unbound fraction with compounds of intermediate hepatic intrinsic clearance.This study was supported by the National Health and Medical Research Council of Australia. 相似文献
140.
P. W. L. Tas H. G. Kress K. Koschel 《Journal of neural transmission (Vienna, Austria : 1996)》1989,76(2):99-107
Summary We have studied the ion flux through the sodium channels of low passage number (<50p.) and high passage number (>150p.) neuroblastoma x glioma hybrid cells using [14C] guanidinium and specific neurotoxins to induce channel opening and closing. The sodium channels of low passage number hybrid cells could be opened by veratridine alone, suggesting the presence of voltage dependent channels in agreement with electrophysiological studies reported in the literature. The sodium channels of the high passage number hybrid cells, however, needed the synergistic action of veratridine and scorpion toxin for activation suggesting that these channels are silent. The [14C] guanidinium ion flux through the sodium channels of the high passage number hybrid cells was inhibited by significantly lower concentrations of the volatile anesthetics (halothane, isoflurane and enflurane) and the lcoal anesthetics (tetracaine and bupivacaine) than the comparable flux through the sodium channels of the low passage number hybrid cells.Dedicated to Prof. Dr. E. Wecker on the occasion of his 65th birthday. 相似文献