全文获取类型
收费全文 | 2011119篇 |
免费 | 167787篇 |
国内免费 | 7692篇 |
专业分类
耳鼻咽喉 | 27343篇 |
儿科学 | 62646篇 |
妇产科学 | 56509篇 |
基础医学 | 281152篇 |
口腔科学 | 57117篇 |
临床医学 | 180276篇 |
内科学 | 402447篇 |
皮肤病学 | 45491篇 |
神经病学 | 165235篇 |
特种医学 | 82198篇 |
外国民族医学 | 431篇 |
外科学 | 315434篇 |
综合类 | 51446篇 |
现状与发展 | 4篇 |
一般理论 | 655篇 |
预防医学 | 161118篇 |
眼科学 | 45278篇 |
药学 | 144186篇 |
5篇 | |
中国医学 | 3541篇 |
肿瘤学 | 104086篇 |
出版年
2018年 | 19314篇 |
2016年 | 17993篇 |
2015年 | 20487篇 |
2014年 | 28815篇 |
2013年 | 43436篇 |
2012年 | 54810篇 |
2011年 | 58457篇 |
2010年 | 35816篇 |
2009年 | 34586篇 |
2008年 | 54904篇 |
2007年 | 59020篇 |
2006年 | 59953篇 |
2005年 | 58246篇 |
2004年 | 56151篇 |
2003年 | 54455篇 |
2002年 | 51901篇 |
2001年 | 91041篇 |
2000年 | 93425篇 |
1999年 | 78436篇 |
1998年 | 24018篇 |
1997年 | 21626篇 |
1996年 | 22341篇 |
1995年 | 22038篇 |
1994年 | 20728篇 |
1993年 | 19522篇 |
1992年 | 65845篇 |
1991年 | 64336篇 |
1990年 | 62272篇 |
1989年 | 59470篇 |
1988年 | 55496篇 |
1987年 | 54669篇 |
1986年 | 51631篇 |
1985年 | 50027篇 |
1984年 | 38453篇 |
1983年 | 32585篇 |
1982年 | 20601篇 |
1981年 | 18750篇 |
1980年 | 17644篇 |
1979年 | 36401篇 |
1978年 | 26370篇 |
1977年 | 22253篇 |
1976年 | 20440篇 |
1975年 | 21749篇 |
1974年 | 26180篇 |
1973年 | 25062篇 |
1972年 | 23535篇 |
1971年 | 21676篇 |
1970年 | 20247篇 |
1969年 | 19319篇 |
1968年 | 17721篇 |
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
951.
The clinical, radiologic, and histopathologic findings of a case of bilateral dacryops is reported in a 49-year-old man. The patient presented with cystic masses located in superior lateral orbits and underwent bilateral excisions of these without any postoperative complications. 相似文献
952.
R D Verhalen 《Journal of urban health》1988,64(7):804-809
953.
954.
955.
956.
Investigation of Role of Nitric Oxide in Protection from Bordetella pertussis Respiratory Challenge
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The mechanism whereby whole-cell pertussis vaccines (WCV) confer protection against Bordetella pertussis is still not fully understood. We have previously reported that macrophage activation produced by vaccination with WCV is associated with induction of NO synthesis by macrophages in response to in vitro stimulation with B. pertussis antigens. To determine whether NO production is an effector of protection or simply a marker of activation, the susceptibility of inducible nitric oxide synthase (type II, iNOS) knockout mice to infection with B. pertussis was examined. We showed that iNOS knockout mice were more susceptible to B. pertussis respiratory challenge than wild-type mice. iNOS-deficient mice also developed a less effective protective response than wild-type mice after the same immunization with WCV. This suggests that NO plays an important role in effecting protection against B. pertussis challenge. 相似文献
957.
Human balancing of an inverted pendulum: position control by small, ballistic-like, throw and catch movements 总被引:12,自引:4,他引:8
In standing, there are small sways of the body. Our interest is to use an artificial task to illuminate the mechanisms underlying the sways and to account for changes in their size. Using the ankle musculature, subjects balanced a large inverted pendulum. The equilibrium of the pendulum is unstable and quasi-regular sway was observed like that in quiet standing. By giving full attention to minimising sway subjects could systematically reduce pendulum movement. The pendulum position, the torque generated at each ankle and the soleus and tibialis anterior EMGs were recorded. Explanations about how the human inverted pendulum is balanced usually ignore the fact that balance is maintained over a range of angles and not just at one angle. Any resting equilibrium position of the pendulum is unstable and in practice temporary; movement to a different resting equilibrium position can only be accomplished by a biphasic 'throw and catch' pattern of torque and not by an elastic mechanism. Results showed that balance was achieved by the constant repetition of a neurally generated ballistic-like biphasic pattern of torque which can control both position and sway size. A decomposition technique revealed that there was a substantial contribution to changes in torque from intrinsic mechanical ankle stiffness; however, by itself this was insufficient to maintain balance or to control position. Minimisation of sway size was caused by improvement in the accuracy of the anticipatory torque impulses. We hypothesise that examination of centre of mass and centre of pressure data for quiet standing will duplicate these results. 相似文献
958.
D. Lothschütz M. Jennewein S. Pahl H.F. Lausberg A. Eichler W. Mutschler R.G. Hanselmann M. Oberringer 《Inflammation research》2002,51(8):416-422
OBJECTIVE AND DESIGN: Inflammatory and tumorous bronchi were screened in order to obtain new tumor relevant cytogenetic parameters. MATERIAL OR SUBJECTS: Bronchial cells of 32 patients were cultivated by standard cell culture procedures. METHODS: Tetraploidy and aneuploidy was determined by enumeration of chromosome 7 and 8 versus the number of centrosomes. The resulting data were correlated with histopathological data. RESULTS: Tetra- and aneuploidy of epithelial cells were detectable in 76% of tumor cell cultures, 75% of high grade inflammatory tissues and 40% of non- and low grade-inflammatory tissues. Additionally, we observed centrosome hyper-amplification and multipolar mitoses not only in the tumor but also in the early stages of inflammation. CONCLUSION: Inflammatory bronchi already show tumor-specific features and may consequently represent the preliminary genetic stage of cancer development in bronchi. 相似文献
959.
Peter E Murray Thomas W Smyth Imad About Remeille Remusat Jean-Claude Franquin Anthony J Smith 《Journal of dentistry》2002,30(1):29-36
OBJECTIVES: The incidence of bacterial microleakage, pulp inflammation and necrosis associated with dentine etching treatments prior to restoration are not known. Consequently, to resolve some of the controversy surrounding the effects and importance of vital dentine etching, the authors investigated these factors. METHODS: 110 standardised class V cavities were cut into buccal dentine, without exposing the pulp of teeth scheduled for extraction for orthodontic reasons. Cavities were either left unetched, or etched with the non-equivalent treatments of phosphoric acid gel for 60s or Ethylenediaminetetraacetic acid (EDTA) for 30s, prior to placement of composite resin. Teeth were collected and pulp responses were evaluated according to ISO guidelines, using pathohistomorphometric analysis and ANOVA statistics. RESULTS: Etching was found to be correlated to bacterial microleakage (p=0.0001) and tertiary dentine formation (p=0.0023). Bacterial microleakage was correlated to inflammatory activity (p=0.0001). The frequency of bacterial microleakage was: no etching (65%), EDTA (51%) and phosphoric acid (PA) (20%). SIGNIFICANCE: Vital dentine etching treatment is of extreme importance for the placement of RC to minimise bacterial microleakage. PA etching proved to be more effective at preventing bacterial microleakage than non-etching, and etching with EDTA. 相似文献
960.
The infertility distress scale (IBS) has been designed to assess the stress perceived by andrological patients resulting from infertility. This review presents findings from different studies with a total of 769 patients. The scale consists of eight items. The stability of scores is very high even for a mean follow-up of 2 years. The scale correlates highly with an already validated measure of infertility distress. Correlations with measures of depressiveness are in the low to medium range. All in all, the psychometric results indicate that the IBS is a factor-stable, reliable and valid instrument for assessing chronic infertility distress in andrological patients. After the presentation of normative data, the usefulness of the IBS as a screening instrument for identifying highly distressed patients is discussed. Findings supporting the scale's sensitivity to change are also presented. The scale is a useful tool in clinical practice as well as in research. 相似文献