全文获取类型
收费全文 | 1927篇 |
免费 | 134篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 32篇 |
妇产科学 | 13篇 |
基础医学 | 284篇 |
口腔科学 | 69篇 |
临床医学 | 117篇 |
内科学 | 337篇 |
皮肤病学 | 45篇 |
神经病学 | 277篇 |
特种医学 | 61篇 |
外科学 | 269篇 |
综合类 | 9篇 |
预防医学 | 55篇 |
眼科学 | 114篇 |
药学 | 200篇 |
中国医学 | 3篇 |
肿瘤学 | 158篇 |
出版年
2023年 | 23篇 |
2022年 | 25篇 |
2021年 | 58篇 |
2020年 | 44篇 |
2019年 | 47篇 |
2018年 | 62篇 |
2017年 | 38篇 |
2016年 | 72篇 |
2015年 | 47篇 |
2014年 | 76篇 |
2013年 | 80篇 |
2012年 | 134篇 |
2011年 | 131篇 |
2010年 | 80篇 |
2009年 | 70篇 |
2008年 | 125篇 |
2007年 | 112篇 |
2006年 | 102篇 |
2005年 | 94篇 |
2004年 | 83篇 |
2003年 | 68篇 |
2002年 | 69篇 |
2001年 | 69篇 |
2000年 | 35篇 |
1999年 | 41篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1993年 | 7篇 |
1992年 | 37篇 |
1991年 | 20篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 15篇 |
1987年 | 20篇 |
1986年 | 16篇 |
1985年 | 16篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1972年 | 5篇 |
1970年 | 3篇 |
1969年 | 5篇 |
排序方式: 共有2070条查询结果,搜索用时 62 毫秒
131.
Okuyemi KS Ebersole-Robinson M Nazir N Ahluwalia JS 《Journal of the National Medical Association》2004,96(9):1208-1211
BACKGROUND: Despite smoking fewer cigarettes per day, African Americans have lower cessation rates and experience disproportionately higher rates of smoking-related health consequences. Because of their high preference for menthol cigarettes, it has been suggested that smoking menthol cigarettes may contribute to the excess smoking-related morbidity experienced by African Americans. Smoking menthol cigarettes could increase health risks from smoking if smokers of menthol cigarettes have lower cessation rates and thereby have longer duration of smoking compared to smokers of nonmentholated cigarettes. Few studies have examined associations between smoking of mentholated cigarettes and smoking cessation among African Americans. This study examined the smoking patterns of menthol cigarette smokers and their smoking cessation experiences. METHODS: A cross-sectional survey of 480 African-American smokers at an inner-city health center. Survey examined sociodemographics, smoking characteristics, and smoking cessation experiences of participants. Menthol smokers (n = 407) were compared to nonmenthol smokers (n = 73) in these characteristics. RESULTS: Menthol smokers were younger and more likely to smoke cigarettes with longer rod length, with filters, and those high in nicotine and tar. Although both groups did not differ by number of past quit attempts, time since most recent quit attempt was shorter for menthol smokers. The durations of most recent and longest-ever quit attempts were nonsignificantly shorter for menthol, compared to nonmenthol smokers. CONCLUSIONS: These data suggest that African-American menthol smokers are less successful with smoking cessation. Prospective studies are needed to confirm these findings and examine mechanisms underlying such differences. 相似文献
132.
The molecular genetic basis and the tumorigenic mechanism of pleomorphic xanthoastrocytoma (PXA) still remain to be elucidated. The amplification of the mdm2 gene and accumulation of the MDM2 protein, which is considered to be one of the major cellular regulators of p53-mediated cell growth control, were studied in eight specimens of PXA obtained from five patients. All of the PXA samples showed at least focal immunopositivity for MDM2. However, none of the samples showed mdm2 gene amplification. These results suggest that accumulation of MDM2 without gene amplification may be one of the major molecular events occurring in the tumorigenesis of PXA. 相似文献
133.
Speech offsets, i.e., sudden transitions from continuous speech sound to silence, activated both hemispheres differently. In addition to peak activities in the bilateral temporal cortices at about 120 ms after the offsets, the right parietal cortex was activated later irrespective of the stimulated ear. The result was discussed in the context of auditory attention. 相似文献
134.
One of the mechanisms repressing apoptosis in tumor cells can involve the expression of anti-apoptotic NF-kappaB target genes. In this study, we demonstrated that a potent NF-kappaB inhibitor, Nalpha-tosyl-L-lysinyl chloromethyl ketone (TLCK), inhibits apoptosis of THP-1 cells triggered by etoposide (VP16), and actinomycin D (ACT D) or cycloheximide inhibits apoptosis. However, persistent activation of NF-kappaB by lipopolysaccharide (LPS) led to the survival of leukemic cells against VP16-induced apoptosis. Thus, the molecular events (Bax/X-chromosome-linked IAP (XIAP)) occurring downstream of NF-kappaB activation during VP16 and/or LPS stimulation may become important to understand the multiple effects of NF-kappaB. 相似文献
135.
Osaki Y Doi K Takasawa M Noda K Nishimura H Ihara A Iwaki T Imaizumi M Yoshikawa T Oku N Hatazawa J Kubo T 《Neuroreport》2004,15(2):287-291
We compared neural activation detected by magnetoencephalography (MEG) during tactile presentation of words and non-words in a postlingually deaf-blind subject and six normal volunteers. The left postcentral gyrus, bilateral inferior frontal gyri, left posterior temporal lobe, right anterior temporal lobe, bilateral middle occipital gyri were activated when tactile words were presented to the right hand of the deaf-blind subject. This set of activated regions was not observed in the normal volunteers, although activation of several combinations of these regions was detected. Positron emission tomography confirmed the location of the MEG-activated areas in the deaf-blind subject. Our results demonstrated that the deaf-blind subject is heavily involved in interpreting tactile language by enhancing cortical activation of cognitive and semantic processing. 相似文献
136.
Inagaki M Matsuoka Y Sugahara Y Nakano T Akechi T Fujimori M Imoto S Murakami K Uchitomi Y 《The American journal of psychiatry》2004,161(12):2263-2270
OBJECTIVE: Patients experiencing their first major depressive episode after receiving a diagnosis of cancer are frequently seen in clinical oncology settings; however, little is known about the neurobiological basis of the first episode. In previous studies, a smaller hippocampus than in healthy comparison subjects has been observed in patients with a history of recurrent and prolonged major depressive episodes. The purpose of the present study was to investigate whether there is an association between hippocampal volume and a first major depressive episode after cancer diagnosis in cancer survivors. METHOD: The subjects were 68 female cancer survivors who had undergone breast cancer surgery 3 or more years earlier (mean interval=4.3 years, SD=0.9). The hippocampal volume and delayed recall function of the 17 cancer survivors who had their first major depressive episode after receiving their cancer diagnosis and the 51 with no history of major depressive episode at any time during their lives were measured by magnetic resonance imaging and the Wechsler Memory Scale-Revised, respectively. RESULTS: The mean duration of the major depressive episode after cancer diagnosis was 11.9 weeks (SD=14.2). There were no significant differences in left or right hippocampal volume or in delayed recall function between the cancer survivors with and without a major depressive episode after cancer diagnosis. CONCLUSIONS: First major depressive episodes after cancer diagnosis in female cancer survivors do not appear to be associated with hippocampal volume. However, a longitudinal study with healthy comparison subjects is needed to draw a definite conclusion. 相似文献
137.
We previously reported that the morphine alkaloid derivative buprenorphine hydrochloride (Bph) induces rapid apoptosis in NG108-15 nerve cells accompanied by the activation of caspase-3. Here, we found this kind of apoptosis was also accompanied by rapid loss of the mitochondrial membrane potential, followed by the efflux of cytochrome c from the mitochondria to the cytosol and the activation of caspases-9 and -3. Together, these results strongly suggested the Bph death signal was routed through the mitochondrial pathway in NG108-15 cells. In these cells, serum-starvation induces a different apoptosis, which we exploited to investigate Bcl-2's role as an apoptosis inhibitor. We made an NG108-15 transfectant, Bcl-2(P2), that stably expressed human Bcl-2, and used it to test Bcl-2's effect on the serum-starvation-induced apoptosis in NG108-15 cells. Cell viability, DNA-ladder formation, and efflux of cytochrome c from the mitochondria were all detected, showing that the human Bcl-2 functioned normally in the Bcl-2(P2) cells. Although the apoptotic events tested were identical in the parental cells and transformants, Bcl-2 expression completely failed to inhibit Bph-induced apoptosis in the Bcl-2(P2) cells. 相似文献
138.
Kakizaki H Zako M Mito H Miyaishi O Nakano T Miyagawa T Iwaki M 《Japanese journal of ophthalmology》2004,48(5):493-496
Purpose To report that the medial canthal tendon (MCT) is not simply the aggregate of the orbicularis oculi muscle (OOM) and its tendon.Methods Twenty eyelids of 10 cadavers were used. The cadavers, seven male and three female, were all Japanese, with an average age of death of 76.2 years. The relationship between the MCT and the OOM, and between the tarsus and Horners muscle were investigated. Histological findings were obtained with hematoxylin and eosin staining.Results The MCT was structured with an anterior lobe, the tendon from the tarsal area of the OOM, and a posterior lobe, the muscle–tendon transition area in the orbital area of the OOM. The nasal aspect of the tarsus was fixed by Horners muscle.Conclusions The MCT and Horners muscle are located in an important area of the eyelid; therefore, it is essential to understand their precise anatomy. Jpn J Ophthalmol 2004;48:493–496 © Japanese Ophthalmological Society 2004 相似文献
139.
Yang YF Mukai T Gao P Yamaguchi N Ono S Iwaki H Obika S Imanishi T Tsujimura T Hamaoka T Fujiwara H 《European journal of immunology》2002,32(8):2124-2132
The chemokine receptors CCR5 and CXCR3 have been implicated as playing a central role in directing a Th1 inflammatory response. Here, we investigated whether a synthetic CCR5 antagonist affects the process of T cell migration to sites of inflammation. Immunization of DBA/1 mice with type II collagen resulted in typical arthritis, which is associated with cellular infiltration. Treatment with a CCR5 antagonist strikingly affected the development of arthritis by reducing both incidence and severity of disease. There was no substantial difference between collagen-immunized mice with and without antagonist treatment in the induction of anti-collagen T cell responses and the capacity to produce IL-12. This endogenous IL-12 functioned to induce comparable levels of CCR5 in these two immunized groups of T cells. Whereas a massive infiltration of inflammatory cells including CCR5(+) T cells occurred in the joints of mice immunized without antagonist, cellular infiltration in the antagonist-treated group was only marginal. These results indicate that administration of a CCR5 antagonist inhibits the development of arthritis not by affecting the generation of collagen-sensitized T cells but by interfering with their migration to joint lesions. 相似文献
140.
Nakamura M 《Shinrigaku kenkyu : The Japanese journal of psychology》2002,73(2):140-147
The purpose of this study is to investigate correlations between anxiety and physical traits of facial expressions. In this study, subjects were divided into two groups on the basis of MAS (manifest anxiety scale), and were taken pictures under three different conditions. In Analysis I, we examined how facial expressions differ between high-anxiety and low-anxiety groups. The results showed that facial expressions differed between two groups especially in mouth, left half of the face, and asymmetry of the face. In Experiment I and II, we investigated whether human beings could identify one's anxiety trait and apparent anxiety in facial expressions only on the basis of its facial expressions. The results showed that one's anxiety trait and apparent anxiety could be detected through the mouth. From these results, human beings can recognize one's anxiety through its facial expressions. 相似文献