全文获取类型
收费全文 | 209103篇 |
免费 | 4932篇 |
国内免费 | 531篇 |
专业分类
耳鼻咽喉 | 2959篇 |
儿科学 | 8159篇 |
妇产科学 | 6239篇 |
基础医学 | 27217篇 |
口腔科学 | 6295篇 |
临床医学 | 16666篇 |
内科学 | 37768篇 |
皮肤病学 | 4924篇 |
神经病学 | 13209篇 |
特种医学 | 11246篇 |
外国民族医学 | 100篇 |
外科学 | 30765篇 |
综合类 | 1389篇 |
一般理论 | 19篇 |
预防医学 | 17423篇 |
眼科学 | 4547篇 |
药学 | 14293篇 |
6篇 | |
中国医学 | 258篇 |
肿瘤学 | 11084篇 |
出版年
2021年 | 608篇 |
2018年 | 3988篇 |
2017年 | 4246篇 |
2016年 | 3546篇 |
2015年 | 5275篇 |
2014年 | 4850篇 |
2013年 | 4113篇 |
2012年 | 10746篇 |
2011年 | 5648篇 |
2010年 | 2737篇 |
2009年 | 4362篇 |
2008年 | 2771篇 |
2007年 | 3589篇 |
2006年 | 3738篇 |
2005年 | 11855篇 |
2004年 | 13333篇 |
2003年 | 8879篇 |
2002年 | 4002篇 |
2001年 | 4664篇 |
2000年 | 2030篇 |
1999年 | 6115篇 |
1998年 | 646篇 |
1992年 | 7005篇 |
1991年 | 7222篇 |
1990年 | 7456篇 |
1989年 | 7037篇 |
1988年 | 6578篇 |
1987年 | 6326篇 |
1986年 | 6035篇 |
1985年 | 5323篇 |
1984年 | 3667篇 |
1983年 | 2962篇 |
1982年 | 1055篇 |
1981年 | 800篇 |
1980年 | 868篇 |
1979年 | 3893篇 |
1978年 | 2407篇 |
1977年 | 1818篇 |
1976年 | 1591篇 |
1975年 | 2514篇 |
1974年 | 3149篇 |
1973年 | 2801篇 |
1972年 | 2787篇 |
1971年 | 2790篇 |
1970年 | 2593篇 |
1969年 | 2499篇 |
1968年 | 2255篇 |
1967年 | 2192篇 |
1966年 | 1923篇 |
1965年 | 1139篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Isabella Sch?ll George Boltz-Nitulescu Erika Jensen-Jarolim 《Journal of controlled release》2005,104(1):1-27
For the treatment of infectious diseases, cancer and allergy, the directed induction of an appropriate immune response is the ultimate goal. Therefore, with the development of pure, often very small proteins, peptides or DNA by molecular biology techniques, the research for suitable adjuvants or delivery systems became increasingly important. Particle formulations are made of a variety of materials, including lipids, proteins or amino acids, polysaccharides, polyacrylic substances or organic acids. Microparticles serve as vehicles and provide a depot for the entrapped or coupled antigen. The release occurs in a pulsatile or continuous manner, a feature, which is well controllable for many particulate systems. Particles attract antigen presenting cells to the administration site, thereby guaranteeing the efficient presentation of the antigen to the immune system. Importantly, particles also protect the entrapped substance. This is especially necessary after oral application to avoid gastric or tryptic breakdown. In this article, the design and construction of different antigen delivery systems and their immune effects, with special focus on the suitability for allergy treatment, are discussed. 相似文献
112.
113.
Fourty-four narcotized rats were split into two equal groups, one being treated with nimodipine and the other with a placebo. By use of norfenefrine the blood pressure was raised to values of 150 and 180 mm Hg within the limits of the autoregulation of brain perfusion and under continuous measurement. Fifteen minutes after application of the standard tracer, horseradish peroxidase, the animals were exsanguinated using a saline perfusion and then perfusion-fixed with Karnovsky's solution. After development of the peroxidase staining the brain sections were evaluated and then allocated to their respective groups. In brain tissues from the experimental group significantly more frequent perivascular accumulations of horseradish peroxidase reaction product were found (P less than 0.001). In electron micrographs it could be seen that the tight junctions were intact and that there was a neuroendothelial transport, with horseradish peroxidase-filled vesicles, in the endothelium, muscle cells, and brain parenchyma. These vesicles represent a medium of transport for all proteins of high molecular weight and can therefore result in brain edema. It is concluded that nimodipine damages the blood-brain barrier by disturbance of the autoregulation of the cerebral blood flow. 相似文献
114.
In experiments on mice and rats quipazine exerts a moderate and short-term anorexigenic activity. N-acyl quipazine derivatives are markedly less toxic, do not exert anorexigenic action and influence weakly the serotoninergic and adrenergic systems. 相似文献
115.
K Thomsen B J Riis J S Johansen C Christiansen P R?dbro 《Gynecological endocrinology》1987,1(2):169-175
Bone turnover before and after withdrawal of estrogen/gestagen treatment was studied in a randomized trial with 110 healthy female volunteers, who had passed a natural menopause 6 months to 3 years before the start of the study. Urinary excretion of intravenously injected 99m-technetium diphosphonate was measured as an index of bone turnover; plasma bone Gla protein and serum alkaline phosphatase were measured as indices of bone formation; and fasting urinary excretion of hydroxyproline and calcium were measured as estimates of bone resorption. During 2 years of hormone treatment, all variables decreased highly significantly (p less than 0.001) to a constant low level. Three months after withdrawal all variables increased highly significantly (p less than 0.001) towards, but not above, pretreatment and placebo levels. We conclude that withdrawal of estrogen/gestagen replacement therapy in postmenopausal women increases bone turnover, but not in excess of pretreatment values. This indicates that bone loss (after withdrawal) is similar to that seen in the placebo group and that a rebound phenomenon is unlikely. 相似文献
116.
P M A van Haaren H P Kok C A T van den Berg P J Zum V?rde Sive V?rding S Oldenborg L J A Stalpers M S Schilthuis A A C de Leeuw J Crezee 《International journal of hyperthermia》2007,23(3):303-314
PURPOSE: The aim of this study was to verify hyperthermia treatment planning calculations by means of measurements performed during hyperthermia treatments. The calculated specific absorption rate (SAR(calc)) was compared with clinically measured SAR values, during 11 treatments in seven cervical carcinoma patients. METHODS: Hyperthermia treatments were performed using the 70 MHz AMC-4 waveguide system. Temperatures were measured using multisensor thermocouple probes. One invasive thermometry catheter in the cervical tumour and two non-invasive catheters in the vagina were used. For optimal tissue contact and fixation of the catheters, a gynaecological tampon was inserted, moisturized with distilled water (4 treatments), or saline (6 treatments) for better thermal contact. During one treatment no tampon was used. At the start of treatment the temperature rise (DeltaT(meas)) after a short power pulse was measured, which is proportional to SAR(meas). The SAR(calc) along the catheter tracks was extracted from the calculated SAR distribution and compared with the DeltaT(meas)-profiles. RESULTS: The correlation between DeltaT(meas) and SAR(calc) was on average R = 0.56 +/- 0.28, but appeared highly dependent on the wetness of the tampon (preferably with saline) and the tissue contact of the catheters. Correlations were strong (R approximately 0.85-0.93) when thermal contact was good, but much weaker (R approximately 0.14-0.48) for cases with poor thermal contact. CONCLUSION: Good correlations between measurements and calculations were found when tissue contact of the catheters was good. The main difficulties for accurate verification were of clinical nature, arising from improper use of the gynaecological tampon. Poor thermal contact between thermocouples and tissue caused measurement artefacts that were difficult to correlate with calculations. 相似文献
117.
Eric Racine Marie-Josée Dion Christine A. C. Wijman Judy Illes Maarten G. Lansberg 《Neurocritical care》2009,11(3):345-352
Background
Advances in intensive care medicine have increased survival rates of patients with critical neurological conditions. The focus of prognostication for such patients is therefore shifting from predicting chances of survival to meaningful neurological recovery. This study assessed the variability in long-term outcome predictions among physicians and aimed to identify factors that may account for this variability. 相似文献118.
Onur Hapa Hüsamettin ?ak?c? Kaan Gidero?lu Kutay ?zturan Aysel Kükner Güler Bu?dayc? 《Archives of orthopaedic and trauma surgery》2009,129(12):1721-1726
Introduction
Ethanol has a suppressive effect on inflammation and the immune system, but the effect of ethanol on tendon healing in vivo has not been studied. The purpose of this study was to investigate the histological and biomechanical effects of ethanol intake on tendon healing in a rat tendon injury model. 相似文献119.
120.
Y Gou?ffic T Piffeteau P Patra 《European journal of vascular and endovascular surgery》2007,33(2):220-222
Paradoxical embolism, describing the passage of venous or right-sided cardiac thrombus into the arterial or systemic circulation through patent foramen ovale, is an uncommon cause of acute arterial occlusion. Here, we report acute Leriche syndrome in a young woman attributable to paradoxical embolism. Ischaemia, patent foramen ovale, and venous thrombosis were the triad of evidence for paradoxical embolism. 相似文献