全文获取类型
收费全文 | 317011篇 |
免费 | 15266篇 |
国内免费 | 745篇 |
专业分类
耳鼻咽喉 | 4135篇 |
儿科学 | 9590篇 |
妇产科学 | 7039篇 |
基础医学 | 44775篇 |
口腔科学 | 11766篇 |
临床医学 | 20750篇 |
内科学 | 69624篇 |
皮肤病学 | 8287篇 |
神经病学 | 26212篇 |
特种医学 | 9047篇 |
外国民族医学 | 27篇 |
外科学 | 37969篇 |
综合类 | 2078篇 |
现状与发展 | 1篇 |
一般理论 | 81篇 |
预防医学 | 35391篇 |
眼科学 | 7292篇 |
药学 | 22124篇 |
中国医学 | 1254篇 |
肿瘤学 | 15580篇 |
出版年
2023年 | 1563篇 |
2022年 | 2373篇 |
2021年 | 5677篇 |
2020年 | 3559篇 |
2019年 | 5806篇 |
2018年 | 9053篇 |
2017年 | 6204篇 |
2016年 | 5982篇 |
2015年 | 6819篇 |
2014年 | 8589篇 |
2013年 | 11755篇 |
2012年 | 19260篇 |
2011年 | 20114篇 |
2010年 | 10099篇 |
2009年 | 8397篇 |
2008年 | 16086篇 |
2007年 | 17280篇 |
2006年 | 16345篇 |
2005年 | 16359篇 |
2004年 | 15401篇 |
2003年 | 14216篇 |
2002年 | 12070篇 |
2001年 | 9503篇 |
2000年 | 9962篇 |
1999年 | 8172篇 |
1998年 | 2199篇 |
1997年 | 1706篇 |
1996年 | 1696篇 |
1995年 | 1454篇 |
1994年 | 1386篇 |
1992年 | 4786篇 |
1991年 | 4460篇 |
1990年 | 4227篇 |
1989年 | 3929篇 |
1988年 | 3655篇 |
1987年 | 3386篇 |
1986年 | 3305篇 |
1985年 | 3136篇 |
1984年 | 2263篇 |
1983年 | 1878篇 |
1979年 | 2102篇 |
1978年 | 1406篇 |
1975年 | 1410篇 |
1974年 | 1654篇 |
1973年 | 1704篇 |
1972年 | 1554篇 |
1971年 | 1480篇 |
1970年 | 1453篇 |
1969年 | 1530篇 |
1968年 | 1553篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
71.
72.
73.
74.
L. Unghváry 《Journal of molecular medicine (Berlin, Germany)》1941,20(18):449-453
Zusammenfassung
Die bogenförmige ST-Strecke kommt häufig, in etwa 12%der Fälle, und die Zwischenzacke selten, in 5der Fälle eines nichtausgewählten Krankenmaterials, vor. Sowohl die Entstehungsursache der bogenförmigen ST-Strecke als der Kischschen Zwischenzacke liegt in der stärkeren oder schwächeren Rechts- oder Linksdeviation der S-Achse. Die Richtung und der Grad der S-Achsendeviation wird es also bestimmen, in wie vielen und welcher Einthovenschen Ableitung die bogenförmige ST-Strecke bzw. die Zwischenzacke notwendigerweise auftreten muß. Bei S-Achsenstellungen zwischen –90°und –30°wird die ST-Strecke in Ableitung I, bei S-Achsenstellungen zwischen –30°und +30°in der I. und II., zwischen +30°und +90°in der I., II., III., zwischen +90°und +150°in der II., III. und bei den Achsenstellungen zwischen +150°und –150°in der III. Einthovenschen Ableitung bogenförmig sein. Die klinische Bedeutung der bogenförmigen ST-Strecke ist gleich mit der klinischen Bedeutung der S-Achsendeviation. Bei dem Vergleich des Herzbefundes der Kranken mit der elektrischen S-Achsenstellung können folgende Feststellungen gemacht werden: Geringergradige Linksdeviation der S-Achse, d. h. bogenförmiges ST
I sowie geringergradige Rechtsdeviation der S-Achse, d. h. STIII kann praktisch bei pathologischem Herzbefund nicht verwertet werden. Stärkere Links- bzw. Rechtsdeviation der S-Achse, d. h. STI undII bzw. STII undIII können im allgemeinen ebenfalls nicht verwertet werden, es ist jedoch wahrscheinlich, daß sie schon einen Übergang zu den pathologischen Befunden bilden. Während jene starken S-Achsendeviationen, wo schon in allen drei Ableitungen bogenförmiges ST besteht, meistens für das Zeichen der myokardialen Läsion betrachtet werden sollen, und zwar in erster Linie dann, wenn die positive S-Zacke in oder neben dem absteigenden Schenkel der R-Zacke gut wahrnehmbar ist. 相似文献
75.
B Bonet M Viana I Sánchez-Vera A Quintanar J Martínez M Espino 《Diabetic medicine》2007,24(11):1192-1198
AIMS: The aims of our study were to determine if insulin resistance is associated with increased plasma levels of non-esterified fatty acids (NEFA), glycerol, 3-hydroxybutyrate and triglycerides in obese children. We also studied whether the presence of acanthosis nigricans (AN) led to further alterations in the above parameters. METHODS: A total of 101 children were studied on their first visit to the paediatric endocrine clinic. Seventy-four were obese, 30 of them with AN. The remaining 27 were non-obese healthy children (control group). NEFAs, glycerol, triglycerides, 3-hydroxybutyrate, insulin, leptin, adiponectin and glucose were determined in blood samples obtained after overnight fasting. The insulin resistance index (IRI) was calculated following the homeostasis model assessment (HOMA). Data from the three groups were compared using appropriate statistical tests. RESULTS: No differences in age, sex ratio and pubertal stage were observed among the three groups. The group of children with the highest body mass index (BMI) showed higher plasma levels of insulin and leptin, higher IRI and lower plasma levels of adiponectin. As insulin and IRI increased, NEFA and 3-hydroxybutyrate decreased and triglycerides increased. When obese children were categorized by BMI, the presence of AN further exacerbated these differences. CONCLUSIONS: In obese children, insulin resistance is associated with plasma lipid alterations suggestive of both decreased adipose tissue lipolysis and hepatic beta-oxidation and increased hepatic synthesis of triglycerides. Such a metabolic condition may facilitate fat storage and hinder weight loss. 相似文献
76.
L Crespo J Graus F García-Hoz R Bárcena L Gil Grande V F Moreira J M Milicua J Sánchez J Blázquez 《Revista española de enfermedades digestivas》2007,99(11):667-670
Hepatic encephalopathy is a reversible state of altered cognition that may occur in patients with acute or chronic liver disease or porto-systemic shunt, and in which known neurological or psychiatric signs may develop. Nitrogenated substances from intestinal digestion reach the brain without being cleared by their passage through the liver due to the presence of porto-systemic shunt. We report two cases of patients with porto-systemic shunt diagnosed with recurrent chronic hepatic encephalopathy refractory to conventional medical treatment. They were satisfactorily treated with shunt embolization using interventionist radiology techniques. 相似文献
77.
E S C Korf E C W van Straaten F-E de Leeuw W M van der Flier F Barkhof L Pantoni A M Basile D Inzitari T Erkinjuntti L-O Wahlund E Rostrup R Schmidt F Fazekas P Scheltens 《Diabetic medicine》2007,24(2):166-171
HYPOTHESIS: Based on recent findings on the association between vascular risk factors and hippocampal atrophy, we hypothesized that hypertension and diabetes mellitus (DM) are associated with medial temporal lobe atrophy (MTA) in subjects without disability, independent of the severity of white matter hyperintensities. METHODS: In the Leukoaraiosis And DISability in the elderly (LADIS) study, we investigated the relationships between DM, hypertension, blood pressure and MTA in 582 subjects, stratified by white matter hyperintensity severity, using multinomial logistic regression. MTA was visually scored for the left and right medial temporal lobe (score 0-4), and meaned. RESULTS: Mean age was 73.5 years (sd 5.1), 54% was female. Of the subjects, 15% had DM, and 70% had a history of hypertension. The likelihood of having MTA score 3 was significantly higher in subjects with DM (OR 2.9; 95% CI: 1.1-7.8) compared with an MTA score of 0 (no atrophy). The odds ratio for MTA score 2 was not significantly increased (OR 1.8; CI: 0.9-4). Systolic and diastolic blood pressure and a history of hypertension were not associated with MTA. There was no interaction between DM and hypertension. Stratification on white matter hyperintensities (WMH) did not alter the associations. CONCLUSION: Our study strengthens the observation that MTA is associated with DM, independently of the amount of small vessel disease as reflected by WMH. 相似文献
78.
Javier Garzón Almudena López-Fando Pilar Sánchez-Blázquez 《Neuropsychopharmacology》2003,28(11):1983-1990
Members of the R7 subfamily of regulators of G-protein signaling (RGS) proteins (RGS6, RGS7, RGS9-2, and RGS11) are found in the mouse CNS. The expression of these proteins was effectively reduced in different neural structures by blocking their mRNA with antisense oligodeoxynucleotides (ODNs). This was achieved without noticeable changes in the binding characteristics of labeled beta-endorphin to opioid receptors. Knockdown of R7 proteins enhanced the potency of antinociception promoted by morphine and [D-Ala(2), N-MePhe(4), Gly-ol(5)]-enkephalin (DAMGO)-both agonists at mu-opioid receptors. The duration of morphine analgesia was greatly increased in RGS9-2 and in RGS11 knockdown mice. The impairment of R7 proteins brought about different changes in the analgesic activity of selective delta agonists. Knockdown of RGS11 reduced [D-Ala(2)]deltorphin II analgesic effects. Those of RGS6 and RGS9-2 proteins caused [D-Ala(2)]deltorphin II to produce a smoothened time-course curve-the peak effect blunted and analgesia extended during the declining phase. RGS9-2 impairment also promoted a similar pattern of change for [D-Pen(2,5)]-enkephalin (DPDPE). RGS7-deficient mice showed an increased response to both [D-Ala(2)]deltorphin II and DPDPE analgesic effects. A single intracerebroventricular (i.c.v.) ED(80) analgesic dose of morphine gave rise to acute tolerance in control mice, but did not promote tolerance in RGS6, RGS7, RGS9-2, or RGS11 knockdown animals. Thus, R7 proteins play a critical role in agonist tachyphylaxis and acute tolerance at mu-opioid receptors, and show differences in their modulation of delta-opioid receptors. 相似文献
79.
Denis Mariano-Goulart Laurent Déchaux Fran?ois Rouzet Eric Barbotte Charles Caderas de Kerleau Michel Rossi Dominique Le Guludec 《Journal of nuclear medicine》2007,48(9):1416-1423
This study aimed to assess the ability of global and local systolic parameters measured with gated blood-pool SPECT (GBPS) to diagnose and characterize the severity of diffuse or localized arrhythmogenic right ventricular dysplasia (ARVD). METHODS: Fifty-nine subjects with symptomatic ventricular arrhythmias were prospectively included in the study. With the International Society and Federation of Cardiology criteria for ARVD as a gold standard, these subjects were classified as subjects without ARVD (21 control subjects) and patients with localized ARVD (16 patients) or diffuse ARVD (22 patients). Right ventricular volumes, right ventricular ejection fractions (EF), the SD of local EF (sigma-EF), and the SD of the local times of end systole (sigma-TES) were computed from GBPS data and compared among the groups in the study population. RESULTS: sigma-EF did not differ between control subjects and patients with diffuse or localized ARVD. Right ventricular EF and volumes differed between patients with diffuse ARVD and control subjects, with similar areas under the receiver-operating-characteristic curves, but right ventricular EF and volumes failed to differentiate patients with localized ARVD. In contrast, sigma-TES differed between patients with diffuse or localized ARVD and control subjects. Regression analysis showed that the systolic parameter most strongly associated with the diagnosis of ARVD was sigma-TES. The probabilities of a randomly chosen patient in the diffuse ARVD group and of a randomly chosen patient in the localized ARVD group having sigma-TES values greater than that of a randomly chosen control subject were 98.5% and 96.7%, respectively. For the diagnosis of localized ARVD, a threshold of 80 ms for sigma-TES corresponded to sensitivity, specificity, and positive and negative predictive values of 100%, 81%, 80%, and 100%, respectively. CONCLUSION: With GBPS, both diffuse ARVD and localized ARVD can be accurately diagnosed by computing sigma-TES for all of the pixels on the surface of the right ventricle. 相似文献
80.