全文获取类型
收费全文 | 39764篇 |
免费 | 2597篇 |
国内免费 | 996篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 586篇 |
妇产科学 | 321篇 |
基础医学 | 5195篇 |
口腔科学 | 651篇 |
临床医学 | 2764篇 |
内科学 | 4530篇 |
皮肤病学 | 232篇 |
神经病学 | 3835篇 |
特种医学 | 1014篇 |
外国民族医学 | 2篇 |
外科学 | 1477篇 |
综合类 | 3097篇 |
现状与发展 | 2篇 |
预防医学 | 3995篇 |
眼科学 | 148篇 |
药学 | 10265篇 |
12篇 | |
中国医学 | 3683篇 |
肿瘤学 | 1446篇 |
出版年
2024年 | 125篇 |
2023年 | 579篇 |
2022年 | 1109篇 |
2021年 | 1381篇 |
2020年 | 1252篇 |
2019年 | 1236篇 |
2018年 | 1209篇 |
2017年 | 1309篇 |
2016年 | 1231篇 |
2015年 | 1164篇 |
2014年 | 1996篇 |
2013年 | 3213篇 |
2012年 | 1771篇 |
2011年 | 2178篇 |
2010年 | 1469篇 |
2009年 | 1749篇 |
2008年 | 1735篇 |
2007年 | 1707篇 |
2006年 | 1435篇 |
2005年 | 1281篇 |
2004年 | 1121篇 |
2003年 | 1011篇 |
2002年 | 893篇 |
2001年 | 854篇 |
2000年 | 645篇 |
1999年 | 660篇 |
1998年 | 665篇 |
1997年 | 577篇 |
1996年 | 562篇 |
1995年 | 536篇 |
1994年 | 459篇 |
1993年 | 446篇 |
1992年 | 450篇 |
1991年 | 413篇 |
1990年 | 385篇 |
1989年 | 391篇 |
1988年 | 347篇 |
1987年 | 338篇 |
1986年 | 325篇 |
1985年 | 444篇 |
1984年 | 400篇 |
1983年 | 279篇 |
1982年 | 352篇 |
1981年 | 276篇 |
1980年 | 284篇 |
1979年 | 208篇 |
1978年 | 220篇 |
1977年 | 159篇 |
1976年 | 194篇 |
1975年 | 79篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
W. Kropf K. Kuschinsky J. Krieglstein 《Naunyn-Schmiedeberg's archives of pharmacology》1989,340(6):718-725
Summary EEG activity after activation of dopamine receptors of D-1 and/or D-2 type was studied by using telemetric recordings in rats. Apomorphine, a preferential D-2 agonist, produced a characteristic increase in the power of alpha-1 band (7.00–9.50 Hz) when given in doses mediating stereotypies (0.2 or 0.5 mg/kg s. c.). Low doses produced a general increase in the power of all of the bands except beta-2. In particular, delta activity was enhanced which seems to be in correspondence with the sedation observed after these doses (0.02 and 0.05 mg/kg). Haloperidol in a dose which is assumed to block both D-1 and D-2 receptors (0.1 mg/kg i. p.) completely antagonized the alpha-1 activation produced by apomorphine (0.5 mg/kg). A similar, although not complete inhibition of alpha-I activation was found after administration of a large dose of the selective D-1 antagonist SCH 23390 (0.2 mg/kg i. p.). The selective agonist at D-2 receptors quinpirole (1.0 mg/kg s. c.) produced a less pronounced activation of the power in the alpha-1 band than apomorphine.In general, there was found to be a good correlation between the activation of the alpha-1 activity and stereotyped behaviour. The results suggest that for the full expression of alpha-1 activation, a pronounced activation of D-2 receptors and at least a minimal activation of D-1 receptors, for instance by the endogenous dopamine, is necessary.
Send offprint requests to K. Kuschinsky at the above address 相似文献
62.
四种口服头孢菌素的体外抗菌活性的比较研究 总被引:2,自引:0,他引:2
本文报道口服Cefixime对900株需氧菌和厌氧菌的体外抗菌作用,并与其它口服的头孢克罗、头孢羟氨苄和头孢氨苄进行了比较。Cefixime对链球菌具较强作用,但对葡萄球菌的作用较差;对肠球菌无效。对肠杆菌科细菌的抗菌活性四者之中以Cefixime最强。Cefixime对头孢氨苄耐药株仍具高度活性,其MIC均值可降低60~1200倍以上。绿脓杆菌、硝酸盐阴性杆菌、鲁氏不动杆菌和产碱杆菌对Cefixime和其它3种头孢菌素的敏感性均较差。四者对厌氧菌的作用除厌氧球菌外其抗菌活性都很弱。Cefixime对β-内酰胺酶稳定,口服吸收良好,抗菌作用强,是一个值得进行临床研究的口服头孢菌素。 相似文献
63.
Skeletal muscle extracellular carbonic anhydrase III was investigated in anesthetized rats by a microdialysis technique. A small dialysis probe was inserted into the tibialis anterior (TA) muscle and perfused continuously. Perfusates were collected before and during muscle contraction, induced by electrical stimulation of the muscle or of the sciatic nerve. In the perfusate of resting normal and denervated muscle, the concentration of CA III was 10 to 12 ng/mL, as measured by a radioimmunosorbent technique. During contractile activity, the concentrations of CA III increased markedly in the normal and denervated muscle. A TA muscle suspended in physiological saline behaved similarly, even though the leakage before and during contraction was higher than in vivo. The results show that skeletal muscle leaks CA III both in vivo and in vitro, a leakage which was markedly increased by contractile activity. The microdialysis technique should also be useful in humans to study the efflux of various proteins from different kinds of diseased or fatigued muscles. 相似文献
64.
Rachel T. Kaiser MD 《Academic emergency medicine》1994,1(6):555-558
Air embolism produced by vaginal insufflation is an unusual but potentially lethal consequence of sexual activity, especially in the pregnant patient. Reported here is the case of a young pregnant woman who presented to the ED in full cardiac arrest, with little history to explain her condition. Despite aggressive resuscitative measures, the patient died, but her infant son was delivered via perimortem cesarean section and survived. A high level of suspicion for air embolism should be maintained for young women who unexpectedly develop cardiac arrest, particularly during sexual activity. Air embolism patients may require vigorous medical resuscitation, hyperbaric oxygen therapy, or surgical intervention to survive. The emergency physician should be familiar with the indications for perimortem cesarean delivery in the third-trimester patient presenting to the ED with cardiac arrest. 相似文献
65.
对天津市新近临床分离的414株细菌进行了甲氟哌酸(Pflx)和氟哌酸(Nflx)体外抗菌活性研究。结果显示Pflx对绝大多数肠杆菌和细菌、不动杆菌有良好抗菌活性,抑菌率>90%。对绿脓杆菌、MSSA及凝固酶阴性葡萄球菌有中度抗菌作用,抑菌率分别为85%、87.5%、87.5%。对MRSA和链球菌抗菌活性稍差,抑菌率在40%~68.42%之间。Nflx体外抗菌活性和Pflx相似。此外,18例药敏试验耐Pflx和Nflx细菌感染患者,经Pflx治疗,肺化脓症1例显效,余17例难治性尿路感染者1例痊愈、9例显效、5例进步、2例无效。 相似文献
66.
67.
Zhao Xiao-zhong 《中国结合医学杂志》1995,(1)
TheEffectsofAstragalusmembranaceusandTripterygiumhypoglaucumonNKActivityinSystemicLupusErythematosusZhaoXiao-zhong(赵小忠)(Depar... 相似文献
68.
V. V. Marlinsky 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1992,90(3):583-588
Summary The influence of locomotor activity upon neurons in the lateral vestibular nucleus was investigated in precollicularly-postmamillary decerebrate guinea pigs. Out of 95 recorded neurons, 24 were identified as vestibulospinal and 71 had no descending projections. Locomotor activity occurred either spontaneously or was prompted by electrical stimulation of the mesencephalic locomotor region. Natural vestibular stimulation was supplied by tilting the animal about its longitudinal axis. Locomotor rhythmic limb muscle activity was accompanied by an increase in the firing frequency in the vast majority of investigated neurons. The increase in frequency was observed at the beginning of ipsilateral forelimb extensor muscle activity. Only in a few non-vestibulospinal neurons was the spontaneous activity depressed during locomotion. An increase in evoked responses was observed in almost all vestibulospinal neurons and in two thirds of the neurons without descending projections. A decrease in evoked responses was observed in one quarter of non-vestibulospinal neurons. During locomotion, the mean and maximal frequencies of evoked neuronal impulse activity changed, but the phase lag of these changes was not altered significantly. The results suggest an enhancement of vestibulospinal influences during locomotion, thus providing a high level of tonus in antigravitational muscles. This is interpreted as a mechanism to ensure that equilibrium is maintained during motion in different gaits and postures. 相似文献
69.
Soluble CD14 but not interleukin-6 is a new marker for clinical activity in atopic dermatitis 总被引:4,自引:0,他引:4
Summary Levels of soluble IL-2 receptors, IL-6, soluble CD23, soluble CD14 and ECP (eosinophilic cationic protein) were measured as markers of T-cell, B-cell, monocyte and eosinophilic leucocyte activation in 26 patients with atopic dermatitis (AD) on admission to (A) and at discharge from (D) the Department of Dermatology in Zurich. The serum levels of sIL-2R, IL-6, sCD23, sCD14 and ECP were significantly elevated in AD patients in comparison with the normal values of healthy donors. A significant decrease in sIL-2R (p=0.0093) and in sCD14 (p=0.0134) levels was demonstrated between A and D, correlating with the improvement in the skin intensity score (SIS). In addition, a significant correlation of the sCD14 levels and the SIS at A was demonstrated (p=0.0415). These results also incriminate monocytes in the pathogenesis of AD, indicating that, besides sIL-2R and ECP, SCD14 could also be a possible marker for the disease activity. 相似文献
70.
Influence of acetylcholine on neuronal activity of monkey amygdala during bar press feeding behavior
L zl L n rd Yutaka Oomura Yasuhiko Nakano Shuji Aou Hitoo Nishino 《Brain research》1989,500(1-2):359-368
Single neuron activity in the monkey amygdala was investigated during cue signalled conditioned bar press feeding behavior and the effects of electrophoretically applied acetylcholine (ACh) and atropine were analyzed. ACh increased the firing rate of one third of the neurons tested; these excitatory responses were inhibited by the muscarinic receptor antagonist atropine. No characteristic location of ACh-sensitive neurons was found, cells were diffusely distributed throughout the amygdala. Activity of ACh-sensitive neurons did not correlate with any particular event during the bar press feeding task. However, continuous application of ACh at low current intensity during the task significantly enhanced the task-related excitatory firing patterns, or markedly attenuated the inhibitory responses. Continuous application of atropine elicited or enhanced inhibitory response patterns. These results suggest that the cholinergic system of the monkey amygdala facilitates neuronal excitation but attenuates inhibition related to various phases of feeding behavior, such as to cue recognition, food aquisition and rewarding process. 相似文献