全文获取类型
收费全文 | 10818篇 |
免费 | 840篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 239篇 |
妇产科学 | 247篇 |
基础医学 | 2070篇 |
口腔科学 | 139篇 |
临床医学 | 1155篇 |
内科学 | 2256篇 |
皮肤病学 | 210篇 |
神经病学 | 727篇 |
特种医学 | 366篇 |
外科学 | 1518篇 |
综合类 | 88篇 |
一般理论 | 2篇 |
预防医学 | 700篇 |
眼科学 | 128篇 |
药学 | 1032篇 |
中国医学 | 11篇 |
肿瘤学 | 701篇 |
出版年
2023年 | 63篇 |
2022年 | 68篇 |
2021年 | 163篇 |
2020年 | 142篇 |
2019年 | 201篇 |
2018年 | 248篇 |
2017年 | 218篇 |
2016年 | 211篇 |
2015年 | 241篇 |
2014年 | 308篇 |
2013年 | 423篇 |
2012年 | 561篇 |
2011年 | 506篇 |
2010年 | 283篇 |
2009年 | 294篇 |
2008年 | 455篇 |
2007年 | 463篇 |
2006年 | 429篇 |
2005年 | 399篇 |
2004年 | 384篇 |
2003年 | 330篇 |
2002年 | 310篇 |
2001年 | 315篇 |
2000年 | 317篇 |
1999年 | 301篇 |
1998年 | 130篇 |
1997年 | 95篇 |
1996年 | 115篇 |
1995年 | 82篇 |
1994年 | 106篇 |
1993年 | 87篇 |
1992年 | 235篇 |
1991年 | 231篇 |
1990年 | 271篇 |
1989年 | 276篇 |
1988年 | 250篇 |
1987年 | 211篇 |
1986年 | 227篇 |
1985年 | 233篇 |
1984年 | 172篇 |
1983年 | 156篇 |
1982年 | 84篇 |
1981年 | 76篇 |
1979年 | 109篇 |
1978年 | 75篇 |
1975年 | 70篇 |
1974年 | 99篇 |
1973年 | 91篇 |
1972年 | 69篇 |
1971年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Diagnosis of congenital toxoplasmosis by two-dimensional immunoblot differentiation of mother and child immunoglobulin g profiles 下载免费PDF全文
Differentiation between the specific immunoglobulin G (IgG) response to Toxoplasma gondii by a mother and her newborn child is helpful in the diagnosis of congenital infection with T. gondii in newborns without T. gondii-specific IgM and/or IgA antibodies at birth. Previous methods include immunoblotting and complexing T. gondii antigen with the sera from the mother and child and comparing the bands after electrophoresis. We developed a two-dimensional immunoblotting (2DIB) method with T. gondii RH strain tachyzoite antigen and validated the method with sera from 11 children identified through the neonatal screening program for congenital toxoplasmosis in Denmark. The children were identified by using Toxoplasma-specific IgM antibodies at the screening test, but the presence of T. gondii-specific IgM and/or IgA antibodies could not be confirmed at the subsequent serum sample tested. The children were monitored for at least 12 months, and in seven of eight patients monitored for 12 months the results of the 2DIB-predicted congenital infection were confirmed by the presence of persistent Toxoplasma-specific IgG antibodies. 2DIB is a sensitive technique that allows early differentiation between passively transferred maternal T. gondii-specific IgG antibodies and antibodies synthesized by the newborn child. 相似文献
102.
Proinflammatory activation of neutrophils and monocytes by Helicobacter pylori is not associated with cagA, vacA or picB genotypes 总被引:1,自引:0,他引:1
Hansen PS Go MF Varming K Andersen LP Graham DY Nielsen H 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》1999,107(12):1117-1123
Chronic Helicobacter pylori infection is associated with mucosal inflammation. The aim of the present study was to assess human neutrophil and monocyte activation induced by H. pylori strains with different virulence genotypes. Bacterial sonicates from 12 strains were used to induce phagocyte up-regulation of adherence molecule CD11b, assessed by fluorescence flow cytometry, and oxidative burst responses, assessed by chemiluminescence. A dose-dependent induction of the expression of CD11b was observed with sonicate from all H. pylori strains on both neutrophils and monocytes. Strains negative for cagA and picB genes had the same inducing activity of upregulation of CD11b as strains positive for these genes. A vacA-S2 type strain had the same activity as vacA-S1 type strains. The induction of toxic oxygen radicals by H. pylori-activated neutrophils gave higher median values for the cagA-positive strains than for the cagA-negative strains. For the monocyte chemiluminescence response, cagA-negative strains gave higher median values compared to cagA-positive strains. We conclude that upregulation of the neutrophil and monocyte adherence molecule CD11b induced by H. pylori sonicates is not associated with the presence of cagA, picB or mosaic pattern of vacA, and that cagA, picB-negative strains and vacA-S2 strains retain their inflammatory capacity. 相似文献
103.
H Danielsen A H Nielsen E B Pedersen P Herlevsen H J Kornerup V Posborg 《Acta medica Scandinavica》1986,219(1):59-66
Angiotensin II (AII), aldosterone (Aldo) arginine vasopressin (AVP) in plasma, serum osmolality (Sosm), and renal sodium excretion (UNaV) were studied before and after infusion of hypertonic sodium chloride solution in 20 patients with adult polycystic kidney disease (PKD) with normal or moderately reduced creatinine clearance (Ccr) and in 10 healthy control subjects. UNaV increased after sodium loading in all, significantly more in the PKD patients. AII and Aldo were normal before sodium loading and suppressed after saline in PKD patients and controls. The increase in VNaV correlated with Aldo in patients but not in controls. AVP before loading was increased in hypertensive PKD patients with reduced Ccr, but not in normotensive patients with normal Ccr. After hypertonic saline, Sosm increased to the same degree both in PKD and control subjects, but AVP increased more in those with PKD. The exaggerated natriuresis of PKD is probably not explained by a change in the activity of the renin-angiotensin-aldosterone system. The enhanced response of AVP to osmotic stimuli in PKD may be a compensatory reaction to a reduced renal tubular effect of AVP. 相似文献
104.
A brief introduction to the Danish Cytogenetic Central Register (DCCR) is given, and possibilities, principles and problems concerning the establishment and maintenance of a national cytogenetic register are presented.
Various data carrier media for registers in general are discussed, of which the magnetic disc is considered most appropriate. General principles for programs capable of performing insertions, deletions and other modifications in the data base are outlined as well as the principles for the programs in the DCCR.
The individual records should preferably be identified by aid of a central person registration number (CPR) rather than by name. The data should be stored and sorted by this identification in order to facilitate retrieval of a desired record. The structure of the records is discussed with regard to prevention of the occurrence of certain errors as well as the optimization of processing.
Flexibility and economy of space are achieved by using programs able to handle records of unequal length, and problems occurring in connection with this are discussed. The question of how to protect sensitive data is dealt with, and two different methods used in the DCCR are outlined. Programs capable of analyzing karyotypes with the purpose of recognizing various cytogenetic syndromes have been developed for use in the DCCR. Various examples of computing times of typical program runs are presented. 相似文献
Various data carrier media for registers in general are discussed, of which the magnetic disc is considered most appropriate. General principles for programs capable of performing insertions, deletions and other modifications in the data base are outlined as well as the principles for the programs in the DCCR.
The individual records should preferably be identified by aid of a central person registration number (CPR) rather than by name. The data should be stored and sorted by this identification in order to facilitate retrieval of a desired record. The structure of the records is discussed with regard to prevention of the occurrence of certain errors as well as the optimization of processing.
Flexibility and economy of space are achieved by using programs able to handle records of unequal length, and problems occurring in connection with this are discussed. The question of how to protect sensitive data is dealt with, and two different methods used in the DCCR are outlined. Programs capable of analyzing karyotypes with the purpose of recognizing various cytogenetic syndromes have been developed for use in the DCCR. Various examples of computing times of typical program runs are presented. 相似文献
105.
Effect of changes in plasma Na+ and Ca++ ion concentration on body temperature during exercise 总被引:1,自引:0,他引:1
B Nielsen 《Acta physiologica Scandinavica》1974,91(1):123-129
106.
The C3b-binding receptor, CR1/CD35, supports CR2/CD21-mediated activation of complement by human B lymphocytes, possibly by associating with CR2 to promote or stabilize the binding of hydrolyzed C3 (C3i), the primary component of the AP convertase, C3i-Bb. To evaluate this hypothesis, we examined the uptake kinetics and binding equilibria for C3i dimer interaction with human blood cells in the absence and presence of CR1- and CR2-blocking mAb. C3i displayed dual uptake kinetics to B lymphocytes, comprising of rapid binding to CR1 and slower binding to CR2. The forward rate constants (k(1)) for CR1 and CR2, operating independently, differed ca. 9-fold (k(1)=193+/-9.4 and 22.2+/-6.0 x 10(3) M(-1)s(-1), respectively). Equilibrium binding of C3i to B lymphocytes was also complex, varying in strength by ca. 13-fold over the C3i concentration range examined. The maximum association constant (K(a, max)=109+/-27.2 x 10(7) l/mole) was ca. 9- and 6-fold greater, respectively, than those for CR1 or CR2 acting alone (K(a)=13.2+/-5.3 and 18.5+/-3.5 x 10(7) l/mole). The high avidity of the CR1-CR2 complex for C3i is consistent with its rates of C3i uptake and release being determined by CR1 and CR2, respectively. 相似文献
107.
108.
109.
Presynaptic control of group Ia afferents in relation to acquisition of a visuo-motor skill in healthy humans 总被引:2,自引:3,他引:2
Monica A. Perez Bjarke K. S. Lungholt Jens B. Nielsen 《The Journal of physiology》2005,568(1):343-354
Sensory information continuously converges on the spinal cord during a variety of motor behaviours. Here, we examined presynaptic control of group Ia afferents in relation to acquisition of a novel motor skill. We tested whether repetition of two motor tasks with different degrees of difficulty, a novel visuo-motor task involving the ankle muscles, and a control task involving simple voluntary ankle movements, would induce changes in the size of the soleus H-reflex. The slope of the H-reflex recruitment curve and the H-max/M-max ratio were depressed after repetition of the visuo-motor skill task and returned to baseline after 10 min. No changes were observed after the control task. To elucidate the mechanisms contributing to the H-reflex depression, we measured the size of the long-latency depression of the soleus H-reflex evoked by peroneal nerve stimulation (D1 inhibition) and the size of the monosynaptic Ia facilitation of the soleus H-reflex evoked by femoral nerve stimulation. The D1 inhibition was increased and the femoral nerve facilitation was decreased following the visuo-motor skill task, suggesting an increase in presynaptic inhibition of Ia afferents. No changes were observed in the disynaptic reciprocal Ia inhibition. Somatosensory evoked potentials (SEPs) evoked by stimulation of the tibial nerve (TN) were also unchanged, suggesting that transmission in ascending pathways was unaltered following the visuo-motor skill task. Together these observations suggest that a selective presynaptic control of Ia afferents contributes to the modulation of sensory inputs during acquisition of a novel visuo-motor skill in healthy humans. 相似文献
110.