全文获取类型
收费全文 | 16935篇 |
免费 | 1202篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 322篇 |
儿科学 | 465篇 |
妇产科学 | 409篇 |
基础医学 | 2493篇 |
口腔科学 | 437篇 |
临床医学 | 1698篇 |
内科学 | 3367篇 |
皮肤病学 | 329篇 |
神经病学 | 1436篇 |
特种医学 | 658篇 |
外国民族医学 | 1篇 |
外科学 | 2291篇 |
综合类 | 240篇 |
一般理论 | 50篇 |
预防医学 | 1577篇 |
眼科学 | 413篇 |
药学 | 1102篇 |
中国医学 | 16篇 |
肿瘤学 | 890篇 |
出版年
2023年 | 60篇 |
2022年 | 99篇 |
2021年 | 258篇 |
2020年 | 136篇 |
2019年 | 255篇 |
2018年 | 313篇 |
2017年 | 244篇 |
2016年 | 282篇 |
2015年 | 330篇 |
2014年 | 436篇 |
2013年 | 783篇 |
2012年 | 931篇 |
2011年 | 1092篇 |
2010年 | 598篇 |
2009年 | 512篇 |
2008年 | 920篇 |
2007年 | 982篇 |
2006年 | 908篇 |
2005年 | 901篇 |
2004年 | 966篇 |
2003年 | 876篇 |
2002年 | 931篇 |
2001年 | 181篇 |
2000年 | 147篇 |
1999年 | 185篇 |
1998年 | 232篇 |
1997年 | 201篇 |
1996年 | 173篇 |
1995年 | 160篇 |
1994年 | 165篇 |
1993年 | 137篇 |
1992年 | 104篇 |
1991年 | 101篇 |
1990年 | 85篇 |
1989年 | 104篇 |
1988年 | 96篇 |
1987年 | 102篇 |
1986年 | 86篇 |
1985年 | 108篇 |
1984年 | 130篇 |
1983年 | 106篇 |
1982年 | 163篇 |
1981年 | 134篇 |
1980年 | 140篇 |
1979年 | 91篇 |
1978年 | 90篇 |
1977年 | 82篇 |
1976年 | 76篇 |
1974年 | 78篇 |
1973年 | 63篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Carl M. Kjellstrand 《Seminars in dialysis》1997,10(4):235-237
It is not a question of dying earlier or later, but of dying well or ill, and dying well means escape from the danger of living ill. (Seneca, 4 BC) 相似文献
43.
44.
45.
Jacobo E. Mintzer M.D. Mark P. Rubert Ph.D. David Loewenstein Ph.D. Edgardo Gamez M.D. Agustin Millor L.C.S.W. Rocio Quinteros M.S. Linda Flores M.D. Meridith Miller R.N. Ph.D. Adrianne Rainerman Carl Eisdorfer Ph.D. M.D. 《Community mental health journal》1992,28(4):293-303
This study assessed Cuban-American Hispanic and White non-Hispanic daughters who were major caregivers for their mothers suffering from Alzheimer's Disease. Although patients in both ethnic groups did not differ in their level of cognitive and functional impairment, Cuban-American Hispanic patients were significantly more likely to be living in their daughters' homes while the White non-Hispanic patients resided in institutional settings. Caregivers were equivalent in their knowledge and utilization of community services, but Cuban-American daughters were significantly more aware of financial aid resources. Cuban-American patients were significantly more depressed than their White non-Hispanic counterparts with daughters showing similar but nonsignificant trends. The impact of cultural factors on caregiving is discussed. 相似文献
46.
Dorsoventral patterning of the Drosophila embryo requires Nudel, a large mosaic protein with a protease domain. Previous studies have implicated Nudel's protease domain as the trigger of a proteolytic cascade that activates the Toll signaling pathway to establish dorsoventral polarity in the embryo. However, the function of other regions of Nudel has been unclear. By using two-dimensional gel electrophoresis and site-directed mutagenesis, we have obtained evidence that the N-terminal region of Nudel contains a site for glycosaminoglycan (GAG) attachment that is required for dorsoventral patterning. Disruption of this site blocks a disulfide-based association between N- and C-terminal Nudel polypeptides and proteolytic activation of Nudel's protease domain. We discuss how a GAG chain on Nudel might be required for Nudel protease activation. 相似文献
47.
48.
49.
Gert Jan Laarman Menco G. Niemeyer Albert V. G. Bruschke Fred J. Verzijlbergen T. Liam Go Ernst E. van der Wall Carl A. P. L. Ascoop 《European journal of nuclear medicine and molecular imaging》1989,15(5):239-243
To establish test specific normal limits for quantitative analysis of uptake and washout of 201Tl after dipyridamole infusion combined with low level exercise, 20 healthy volunteers were studied with low likelihood of coronary artery disease (CAD) assessed by a stepwise probability analysis based on age, sex, symptoms, resting electrocardiogram, and exercise electrocardiography. Likelihood of CAD in these volunteers was calculated as 1%. After dipyridamole infusion combined with low level exercise, one volunteer complained of headache; no other side effects were observed. There were no chest pain complaints. Maximal hemodynamic changes were achieved during the 6th and 7th min of the test. No ST segment depression was recorded. Visual analysis of the 201Tl scintigrams was normal in all volunteers. Mean regional washout at 4 h was 44.37%±2.11%. The regional washout in the 70° LAO view (46.65%±1.10%) was significantly higher than in the anterior and 30° LAO views (43.44%±1.50% and 43.02%±1.45%, respectively). Profiles of uptake and washout of 201Tl were different after dipyridamole infusion combined with low level exercise as compared to maximal exercise. Thus, in quantitative analysis of 201Tl scintigraphy after dipyridamole infusion in conjunction with low level exercise as applied in the present study, it is mandatory to use normal limits of uptake and washout of 201Tl derived from healthy volunteers who underwent the same combined protocol. 相似文献
50.
Zusammenfassung Aus eigener Zucht stammende Larven, Nymphen und Imagines von Amblyomma testudinis wurden auf ihre Sinnesleistungen hinsichtlich Phototaxis, Thermotaxis, Geotaxis und Chemotaxis untersucht. Es ergab sich ein entwicklungsabhängiger Wandel im phototaktischen Verhalten von anfangs positiver Phototaxis bei den Larven über indifferente Phototaxis bei vollgesogenen Larven und nüchternen Nymphen zu negativer Phototaxis bei vollgesogenen Nympen sowie - und -Imagines. Sämtliche Entwicklungsstadien mit Ausnahme der -Imagines verhalten sich temperaturindifferent vor dem Kontakt mit einem Wirt; vollgesogene Larven und Nymphen dagegen bevorzugen niedrige Temperaturen. Nymphen und Imagines, die noch nicht gesogen haben, reagieren negativ geotaktisch. Sie erklettern vermutlich in der Natur die Spitzen von Pflanzen und Steinen, um dort das Vorbeikriechen eines Wirtes abzuwarten. Imagines von Amblyomma testudinis reagieren mit einer positiven Chemotaxis auf Schlangen stärker als auf Kröten. Auch Substrat aus Schlangenbehältern enthält mindestens für 30 Std nach der Entfernung der Schlangen chemotaktisch wirksame Stoffe.
Contributions to sensory physiology of the tick Amblyomma testudinis
Summary Phototaxis, thermotaxis, geotaxis and chemotaxis of larvae, nymphs and adults of Amblyomma testudinis from own breedings were studied. The phototactic behaviour changed according to the different stages of development: unfed larvae were positively phototactic, fed larvae and unfed nymphs were indifferent, fed nymphs but also the adults showed a negative phototaxis.—All stages of development besides the females reacted without any preference for a distinct temperature, whereas larvae and nymphs after feeding prefered lower temperatures.—Unfed nymphs and adults were negatively geotactic which corresponds to their natural behaviour of climbing plants for catching hosts.—Adults of Amblyomma testudinis showed a higher rate of chemotaxis for snakes than for toads; substrate from snake cages containes chemotaxis inducing substances for more than 30 hours after elimination of the snakes.相似文献