全文获取类型
收费全文 | 9505篇 |
免费 | 445篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 81篇 |
儿科学 | 151篇 |
妇产科学 | 78篇 |
基础医学 | 1491篇 |
口腔科学 | 272篇 |
临床医学 | 858篇 |
内科学 | 1624篇 |
皮肤病学 | 149篇 |
神经病学 | 1101篇 |
特种医学 | 861篇 |
外科学 | 1345篇 |
综合类 | 41篇 |
一般理论 | 3篇 |
预防医学 | 316篇 |
眼科学 | 243篇 |
药学 | 676篇 |
中国医学 | 24篇 |
肿瘤学 | 681篇 |
出版年
2024年 | 9篇 |
2023年 | 35篇 |
2022年 | 82篇 |
2021年 | 148篇 |
2020年 | 105篇 |
2019年 | 138篇 |
2018年 | 165篇 |
2017年 | 134篇 |
2016年 | 193篇 |
2015年 | 251篇 |
2014年 | 303篇 |
2013年 | 367篇 |
2012年 | 583篇 |
2011年 | 635篇 |
2010年 | 411篇 |
2009年 | 407篇 |
2008年 | 637篇 |
2007年 | 682篇 |
2006年 | 697篇 |
2005年 | 719篇 |
2004年 | 646篇 |
2003年 | 644篇 |
2002年 | 615篇 |
2001年 | 124篇 |
2000年 | 105篇 |
1999年 | 122篇 |
1998年 | 123篇 |
1997年 | 91篇 |
1996年 | 90篇 |
1995年 | 84篇 |
1994年 | 82篇 |
1993年 | 60篇 |
1992年 | 42篇 |
1991年 | 43篇 |
1990年 | 32篇 |
1989年 | 31篇 |
1988年 | 28篇 |
1987年 | 36篇 |
1986年 | 22篇 |
1985年 | 18篇 |
1984年 | 25篇 |
1983年 | 25篇 |
1982年 | 23篇 |
1981年 | 26篇 |
1980年 | 16篇 |
1979年 | 25篇 |
1978年 | 20篇 |
1977年 | 17篇 |
1976年 | 13篇 |
1975年 | 8篇 |
排序方式: 共有9995条查询结果,搜索用时 15 毫秒
21.
Jürgen Vogt Torsten Schwarz Daniel Gras Johannes Sperzel Philippe Ritter Willem de Voogt Jean-Pierre Cebron Martin Seifert Bruce Tockman Bernd Schubert Eric Johnson Annette Doelger Thierry Pochet Elisabeth Mouton Christian Butter 《Journal of interventional cardiac electrophysiology》2007,19(1):61-68
Introduction Failure to enter the coronary sinus (CS) with a guiding catheter and entering its tributaries remains challenging in left
ventricle (LV) pacing lead implants for cardiac resynchronization therapy (CRT). A dual telescoping catheter system (8F outer/6F
inner) is designed to provide the ability to adjust the catheter curve size, shape and/or reach to the patients’ anatomy avoiding
the need for catheter change.
Methods Five different designs for CS cannulation were randomly tested in 64 patients scheduled for CRT device implant.
Results In 33 consecutive patients three adaptable telescoping guiding catheter systems were tested per patient, the adaptable catheters
had higher overall cannulation success rates (68, 63 and 62%) compared to the fixed shape catheter (46%) and an greater cannulation
success rate when the CS location was not known (70, 53 and 72% vs 33% for the fixed shape). In a second group of 31 CRT patients
the two telescoping catheters had similar high levels of success (71–80%), with or without using the inner catheter.
Conclusions The telescopic system is adaptable to a wide range of anatomical variations in patients and can result in a higher CS cannulation
success rate due to its adjustability in the RA in search for the CS ostium. On top of this the inner catheter allows for
sub-selecting the CS tributaries. 相似文献
22.
A 72-year-old man with increasing shortness of breath and atypicalangina pectoris received a chest radiograph 相似文献
23.
24.
Thompson Debra A.; Janecke Andreas R.; Lange Jessica; Feathers Kecia L.; Hubner Christian A.; McHenry Christina L.; Stockton David W.; Rammesmayer Gabriele; Lupski James R.; Antinolo Guillermo; Ayuso Carmen; Baiget Montserrat; Gouras Peter; Heckenlively John R.; den Hollander Anneke; Jacobson Samuel G.; Lewis Richard A.; Sieving Paul A.; Wissinger Bernd; Yzer Suzanne; Zrenner Eberhart; Utermann Gerd; Gal Andreas 《Human molecular genetics》2006,15(9):1559
Human Molecular Genetics 相似文献
25.
Safety of thrombolysis during cardiopulmonary resuscitation. 总被引:15,自引:0,他引:15
The prognosis is generally poor for patients who experience a cardiac arrest. The most common causes of sudden cardiac arrest are massive pulmonary embolism (PE) and acute myocardial infarction (MI). While thrombolysis is a first-line treatment option in massive PE and acute MI, cardiopulmonary resuscitation (CPR) has been regarded as a relative contraindication for thrombolysis because of the anticipated bleeding risk caused by traumatic cardiocompressions. However, an increasing number of case reports and clinical studies on thrombolysis during and after CPR highlight an increased frequency of the return of spontaneous circulation and a better neurological outcome of surviving patients. These effects are mainly due to the thrombolysis of macroscopic blood clots and the amelioration of microcirculatory reperfusion.This article reviews case reports and clinical studies of thrombolysis during and shortly after CPR in order to estimate the risk of severe bleeding events caused by CPR in association with thrombolysis compared with CPR without thrombolysis.Although thrombolysis per se can cause severe and potentially fatal haemorrhage, there is no evidence that severe bleeding events occur more often when thrombolysis is combined with cardiocompressions. In addition, by far the majority of bleeding complications can be treated effectively. Thus, in many cases, the possible benefit of thrombolysis during CPR seems to outweigh the potential risks. However, there may be a publication bias in some case reports and studies towards reporting successful rather than unsuccessful CPRs. In addition, not enough controlled clinical trials have yet been conducted. Therefore, data from large randomised, multicentre studies are needed to definitely answer the question of the relationship between safety and efficacy of this promising treatment option.We conclude that the currently available data do not indicate that thrombolysis contributes to a significant increase in bleeding complications when administered during CPR. 相似文献
26.
27.
Maria Severin Bernd Kirchhof 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》1990,228(1):101-104
Three keratoplasties were carried out on two patients because of nodular degeneration of the cornea. Progress after keratoplasty
could be followed up in one eye for 17 months and in the other two eyes, for 2.5 and 9 years, respectively. The implant with
the short follow-up of only 17 months remained glass-clear; nothing abnormal was discovered during the checkups. In the case
of the other patient in whom a longer follow-up period was possible, the following findings were evident: (1) a remarkably
late epithelial immune response in one eye (after 18 months) with subsequent incomplete reepithelisation and formation of
fine, superficial, cloudy opacity (observation period 2.5 years); (2) formation of dense but flat, superficial areas of opacity
in the cornea of the other eye (observation period 9 years). These areas may be regarded as a precursor of Salzmann’s corneal
degeneration. No difference could be found between the histological findings in the explants and those in a degenerative pannus
or an older scar caused by inflammation of the Bowman membrane. 相似文献
28.
P Bernd 《Brain research》1987,430(1):31-38
It has been shown previously that a subpopulation of long-term (7-14 days) cultured neural crest cells undergoing differentiation possesses receptors for nerve growth factor (NGF). These cells are likely to be targets of NGF during the early stages of embryonic development. This study was conducted to determine whether cells exhibiting neuron-like characteristics (i.e. process formation, presence of putative neurotransmitters) in neural crest cultures have NGF receptors. This was accomplished by combining 125I-NGF radioautography and immunocytochemistry using antibodies against tyrosine hydroxylase, serotonin, and vasoactive intestinal polypeptide. Examination of light microscopic radioautographs revealed that none of the neuron-like cells with tyrosine hydroxylase-like, serotonin-like, or vasoactive intestinal polypeptide-like immunoreactivity bound 125I-NGF, and, therefore, do not possess NGF receptors. It is not known whether the lack of NGF receptors on neuron-like cells is due to the early developmental stage of these cells, or is caused by a difference in the microenvironment in vitro as compared to in vivo. The identity of the cultured neural crest cells which do possess NGF receptors remains to be determined. 相似文献
29.
Summary A single glass micropipette voltage clamp technique with intracellular dialysis was used to study the effects of the trapidil derivatives AR 12–456 and AR 12–463 on Ca channel currents carried by Bat+ in isolated ventricular cells from mice hearts. Inspite of a more potent inhibition of the cAMP phosphodiesterase from heart (Bartel et al. 1985) a reversible Ca channel blocking action of both compounds could be observed. The concentration of half maximal block was calculated to about 50 mol/l for both derivatives tested. Neither a shift in the current-voltage relationships nor a significant change in the potential for half maximal activation was found. The maximal Ba2+ -conductance was reduced. The steady state inactivation was shifted towards more negative potentials by application of 100 mol/l AR 12–463. The decay of the Ba currents was accelerated in the range of the applied test potentials between –20 and +20 mV. It is concluded that the new trapidil derivatives with more potent inhibitory action on cardiac phosphodiesterase than trapidil can block myocardial Ca channels.
Send offprint requests to B. Nilius 相似文献
30.
CGP 6809 — A new nitrosoureido-sugar derivative with activity in human tumor xenografts 总被引:1,自引:0,他引:1
Heinz H. Fiebig Karl H. Widmer Bernd R. Winterhalter Georg W. Löhr 《Cancer chemotherapy and pharmacology》1989,23(6):337-340
Summary CGP 6809 [ethyl-6-deoxy-3,5-di-O-methyl-6-(3-methyl-3-nitrosoureido)--d-glucofuranoside] is a new methylnitrosoureido-sugar derivative that has been shown to be active against a broad spectrum of transplantable tumours in mice and rats [14]. We investigated the anti-tumour effect of CGP 6809 in ten selected, human tumour xenograft lines growing s. c. in nude mice. The p. o. administration of 125 mg/kg per day for 10–15 days was less toxic (lethality 12% in tumour-bearing nude mice) than the i. p. injection of 62.5 mg/kg per day (lethality 22%). The anti-tumour effect was similar for both application routes; two large bowel cancers responded to treatment with CGP 6809, rectal cancer CXF 158 showed a remission, and the rapidly growing, undifferentiated colonic cancer CXF 280 exhibited a transient no-change. Furthermore, remissions were observed in the epidermoid lung cancer LXF 322 and in thyroid cancer 117. Tumour progression was found in another epidermoid lung cancer and in three stomach cancers, one melanoma, and one soft tissure sarcoma. CGP 6809 is a promising new agent for clinical trials, especially for large bowel and epidermoid lung cancer.Supported in part by grant PTB 8467 from the Bundesminister für Forschung und Technologie, Bonn, FRG 相似文献