全文获取类型
收费全文 | 2891968篇 |
免费 | 222930篇 |
国内免费 | 5490篇 |
专业分类
耳鼻咽喉 | 38990篇 |
儿科学 | 95793篇 |
妇产科学 | 80376篇 |
基础医学 | 410697篇 |
口腔科学 | 85941篇 |
临床医学 | 259454篇 |
内科学 | 559912篇 |
皮肤病学 | 64094篇 |
神经病学 | 229218篇 |
特种医学 | 112325篇 |
外国民族医学 | 698篇 |
外科学 | 438753篇 |
综合类 | 70404篇 |
现状与发展 | 6篇 |
一般理论 | 1020篇 |
预防医学 | 220595篇 |
眼科学 | 68967篇 |
药学 | 215932篇 |
9篇 | |
中国医学 | 6469篇 |
肿瘤学 | 160735篇 |
出版年
2018年 | 30738篇 |
2017年 | 23643篇 |
2016年 | 26151篇 |
2015年 | 29838篇 |
2014年 | 41517篇 |
2013年 | 61796篇 |
2012年 | 84719篇 |
2011年 | 89369篇 |
2010年 | 52897篇 |
2009年 | 49632篇 |
2008年 | 83732篇 |
2007年 | 88698篇 |
2006年 | 89623篇 |
2005年 | 86273篇 |
2004年 | 84131篇 |
2003年 | 80282篇 |
2002年 | 77868篇 |
2001年 | 140994篇 |
2000年 | 145024篇 |
1999年 | 121397篇 |
1998年 | 32905篇 |
1997年 | 29286篇 |
1996年 | 29210篇 |
1995年 | 28206篇 |
1994年 | 26243篇 |
1993年 | 24410篇 |
1992年 | 96163篇 |
1991年 | 93412篇 |
1990年 | 90558篇 |
1989年 | 87350篇 |
1988年 | 80479篇 |
1987年 | 78902篇 |
1986年 | 74980篇 |
1985年 | 71958篇 |
1984年 | 53326篇 |
1983年 | 45786篇 |
1982年 | 26378篇 |
1981年 | 23606篇 |
1979年 | 49418篇 |
1978年 | 34082篇 |
1977年 | 28969篇 |
1976年 | 27183篇 |
1975年 | 28786篇 |
1974年 | 35105篇 |
1973年 | 33743篇 |
1972年 | 31177篇 |
1971年 | 29238篇 |
1970年 | 27043篇 |
1969年 | 25322篇 |
1968年 | 23318篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Noninvasive examination of the venous system in the leg: presclerotherapy evaluation 总被引:1,自引:0,他引:1
H S Fronek 《The Journal of dermatologic surgery and oncology》1989,15(2):170-173
Sclerotherapy of varicose veins and telangiectasia should be preceded by a directed medical history and physical examination. Factors including the presence of significant venous disease should prompt a more extensive evaluation. Of the physical examination techniques and noninvasive technologies available, Doppler ultrasound provides the most pertinent information, but the potential uses of each method are described. 相似文献
992.
Lineage commitment and differentiation of T and natural killer lymphocytes in the fetal mouse 总被引:4,自引:0,他引:4
Summary: T cells and natural killer (NK) cells are presumed to share a common intrathymic precursor. The development of conventional a|3 T lymphocytes begins within the early fetal thymus, after the colonization of multipotent CDl1 71 precursors. Irrevocable commitment to the T lineage is marked by thymus-induced expression of CD25. However, the contribution of the fetal thymus to NK lineage commitment and differentiation remains largely unappreciated. Recently, we demonstrated that the development of functional mouse NK cells occurs first in the fetal thymus. Moreover, the appearance of mature fetal thymic NK cells (NK1.1+ /CD 117- ) is preceded by a thymus-induced developmental stage (NKl.1+ /CD1 17+ ) that marks lineage commitment of multipotent hematopoietic precursors to the T and NK-cell fates. Commitment to the T/NK bipotent stage is induced by fetal thymic stroma, but is not thymus dependent. Recent data indicate that CD90+ /CD117lo fetal blood prothymocytes exhibit NK lineage potential and are phenotypically and functionally identical to fetal thymic NK1,1+ /CD1 17+ progenitors. This finding also indicates that full commitment of circulating precursors to the T-cell lineage occurs after thymus colonization. In this review, we discuss recent insights into the cellular and molecular events involved in fetal mouse T and NK lineage commitment and differentiation to unipotent progenitors. 相似文献
993.
Summary. In this study, we have examined our records for the isolation of Candida tropicalis from clinical specimens of patients with heterogeneous clinical presentations during the past 5 years. We have found that this species ranks third among all yeasts in frequency of isolation from clinical specimens and that the trend of recovery from the specimens is rising over the years. The isolation rate of C. tropicalis was highest from urine specimens (36%) followed by respiratory specimens (22%). The frequency of isolation of C. tropicalis from vaginal specimens was relatively high (14%), however the trend was declining over the years. In general, the high recovery of Candida tropicalis from clinical specimens of patients with variable disease supports the views of this organism being a major pathogen.
Zusammenfassung. Die Studie basiert auf einer Durchsicht der Patientenarchive der letzten fünf Jahre auf die Isolationshäufigkeit von Candida tropicalis aus klinischen Untersuchungsmaterialien von Patienten mit unterschiedlichen klinischen Krankheitsbildern. Diese Hefeart war die dritthäufigste mit steigender Tendenz über die Jahre. Die Isolierungsrate von C. tropicalis war am höchsten aus Urin (36%), gefolgt von Respirationstrakt-Materialien (22%). Die Isolationshäufigkeit aus dem hinteren Scheidengewölbe war relativ hoch (14%), nahm jedoch mit den jahren ab. Allgemein unterstreicht die hohe Isolationsrate von C. tropicalis aus klinischen Untersuchungsmaterialien die ätiologische Bedeutung dieses Erregers. 相似文献
Zusammenfassung. Die Studie basiert auf einer Durchsicht der Patientenarchive der letzten fünf Jahre auf die Isolationshäufigkeit von Candida tropicalis aus klinischen Untersuchungsmaterialien von Patienten mit unterschiedlichen klinischen Krankheitsbildern. Diese Hefeart war die dritthäufigste mit steigender Tendenz über die Jahre. Die Isolierungsrate von C. tropicalis war am höchsten aus Urin (36%), gefolgt von Respirationstrakt-Materialien (22%). Die Isolationshäufigkeit aus dem hinteren Scheidengewölbe war relativ hoch (14%), nahm jedoch mit den jahren ab. Allgemein unterstreicht die hohe Isolationsrate von C. tropicalis aus klinischen Untersuchungsmaterialien die ätiologische Bedeutung dieses Erregers. 相似文献
994.
为探讨脂质过氧化损伤及自由基在新生儿硬肿症发病机理中的作用,将观察对象分为疾病组和对照组,疾病组于入院时,对照组于出生后1周内取静脉血检测血浆脂质过氧化物及红细胞超氧化物歧化酶含量。 相似文献
995.
996.
There has been a remarkable change in the scenario of therapeutic apheresis in the last 14 years in India. The crude method of manual removal of blood followed by separation of plasma by gravity, keeping it in the bottle for a long time, has now been totally replaced by plasmapheresis, centrifugation, membrane filtration, and immunoadsorption techniques. The indications for use have also changed from a list of limited indications in the beginning to include all immune complex disorders. The clinical beneficiaries have also increased from blood bankers to nephrologists and immunologists in addition to oncologists. Efforts are now underway with the help of the Indian Society for Apheresis (founded in 1985) to popularize the newer methods of cryofiltration, photopheresis and heparin extracorporeal low-density lipoprotein (HELP) and DALI apheresis systems besides the specialized techniques of immunoadsorption using filters, columns, or ligands. This is suggestive of a positive trend for the treatment of immune complex disorders. 相似文献
997.
998.
999.
J. R. Martin 《Autonomic & autacoid pharmacology》1997,17(4):249-259
1 Intravenous administration of the ganglionic nicotinic receptor agonist DMPP (1,1-dimethyl-4-phenylpiperazinium iodide) into urethane-anaesthetized rats evoked dose-dependent increases in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA). 2 The ganglionic nicotinic receptor antagonists pentolinium and hexamethonium either alone or combined did not inhibit the increase in RSNA and MAP evoked by 50 to 200 μg kg?1 doses of DMPP. The increase in renal sympathetic nerve activity evoked by DMPP occurred as a brief burst in firing. 3 The increase in MAP, but not RSNA, evoked by DMPP in the presence of pentolinium was inhibited by the selective α1-adrenergic receptor antagonist prazosin. 4 The non-selective α-adrenoceptor and NPY receptor antagonist benextramine also inhibited the increase in MAP without inhibiting the increase in RSNA. Surprisingly, the combination of benextramine and pentolinium, or benextramine and hexamethonium, completely blocked the DMPP-evoked increase in RSNA and thus the increase in MAP. 5 The uptake1 antagonist desipramine combined with pentolinium did not affect the DMPP-evoked increases in MAP or RSNA when compared to the responses evoked in the presence of pentolinium alone. 6 Adding the selective M1 muscarinic receptor antagonist telenzepine to pentolinium and prazosin did not inhibit the increase in RSNA evoked by a 100 μg kg?1 dose of DMPP. 7 While the DMPP-evoked increase in MAP in the presence of ganglionic nicotinic receptor antagonists is primarily dependent upon activation of α1-adrenoceptors, the increase in RSNA occurs via activation of ganglionic nicotinic receptors and activation of a mechanism susceptible to blockade by benextramine. 相似文献
1000.