全文获取类型
收费全文 | 18628篇 |
免费 | 1154篇 |
国内免费 | 277篇 |
专业分类
耳鼻咽喉 | 335篇 |
儿科学 | 221篇 |
妇产科学 | 252篇 |
基础医学 | 3034篇 |
口腔科学 | 252篇 |
临床医学 | 1338篇 |
内科学 | 3591篇 |
皮肤病学 | 715篇 |
神经病学 | 1482篇 |
特种医学 | 1394篇 |
外科学 | 2525篇 |
综合类 | 73篇 |
一般理论 | 2篇 |
预防医学 | 697篇 |
眼科学 | 515篇 |
药学 | 1743篇 |
中国医学 | 300篇 |
肿瘤学 | 1590篇 |
出版年
2023年 | 150篇 |
2022年 | 439篇 |
2021年 | 638篇 |
2020年 | 370篇 |
2019年 | 519篇 |
2018年 | 579篇 |
2017年 | 501篇 |
2016年 | 773篇 |
2015年 | 1004篇 |
2014年 | 1182篇 |
2013年 | 1308篇 |
2012年 | 1858篇 |
2011年 | 1727篇 |
2010年 | 1132篇 |
2009年 | 890篇 |
2008年 | 1054篇 |
2007年 | 1029篇 |
2006年 | 903篇 |
2005年 | 865篇 |
2004年 | 661篇 |
2003年 | 589篇 |
2002年 | 494篇 |
2001年 | 148篇 |
2000年 | 137篇 |
1999年 | 121篇 |
1998年 | 82篇 |
1997年 | 65篇 |
1996年 | 48篇 |
1995年 | 50篇 |
1994年 | 29篇 |
1993年 | 38篇 |
1992年 | 55篇 |
1991年 | 60篇 |
1990年 | 50篇 |
1989年 | 43篇 |
1988年 | 32篇 |
1987年 | 41篇 |
1986年 | 37篇 |
1985年 | 36篇 |
1984年 | 32篇 |
1983年 | 25篇 |
1982年 | 14篇 |
1981年 | 16篇 |
1980年 | 16篇 |
1979年 | 19篇 |
1978年 | 29篇 |
1977年 | 16篇 |
1976年 | 15篇 |
1973年 | 21篇 |
1969年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Yang Hee Lee Ihn Rhan Lee Won Sick Won Chung Hee Park 《Archives of pharmacal research》1988,11(3):247-249
42.
Summary 1. The effects of microinjection of 5-hydroxytryptamine (5-HT) or its antagonists methysergide (a 5-HT1 receptor antagonist), cyproheptadine (a mixed 5-HT1/5-HT2 receptor antagonist), or ketanserin (a 5-HT2 receptor antagonist) into the preoptic anterior hypothalamus on thermoregulatory responses were assessed in conscious rabbits at different ambient temperatures (T
a). 2. Intrahypothalamic injection of 5-HT caused dose-dependent hypothermia in rabbits when the T
a was 2°C and 22°C. At 2°C the hypothermia was due to decreased metabolism, whereas at 22°C the hypothermia was due to increased peripheral blood flow and increased respiratory evaporative heat loss. 3. In contrast, administration of either cyproheptadine, methysergide or ketanserin into the 5-HT-sensitive sites in the preoptic anterior hypothalamus caused dose-dependent hyperthermia in rabbits when the T
a was 2°C, 22°C and 32°C. At 2°C the hyperthermia was due to increased metabolism, whereas at 32°C the hyperthermia was due to decreased peripheral blood flow and decreased respiratory evaporative heat loss. At 22°C, the hyperthermia was due to increased metabolism and decreased peripheral blood flow. 4. For a given intrahypothalamic dose (e.g.15–20 g), either methysergide, cyproheptadine or ketanserin produced the same degree of rectal temperature elevation (e.g. about 1.4°C) in rabbits. Thus, there did not appear to be any association between hypothalamic 5-HT receptor types and thermoregulation. 5. However, the present results suggest that hypothalamic 5-HT receptors mediate thermoregulatory responses in the rabbit. Activation of hypothalamic 5-HT receptors decreases heat production and increases heat loss, whereas inhibition of hypothalamic 5-HT receptors increases heat production and decreases heat loss in the rabbit.This study was supported by grants from the National Science Council of the Republic of China.
Send offprint requests to S. J. Won at the above address 相似文献
43.
Overexpression of S100A4 is closely related to the aggressiveness of gastric cancer 总被引:25,自引:0,他引:25
Cho YG Nam SW Kim TY Kim YS Kim CJ Park JY Lee JH Kim HS Lee JW Park CH Song YH Lee SH Yoo NJ Lee JY Park WS 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2003,111(5):539-545
Elevated levels of the calcium-binding protein S100A4 cause metastasis of benign rat mammary tumor cells. To investigate whether S100A4 plays an important role in the invasion and metastasis of gastric cancers, we examined the gene mutations in the coding regions and expression patterns of the S100A4 in gastric adenocarcinoma in Korea. Moderate to strong expression of S100A4 was found in 53 (68.8%) of the 77 gastric adenocarcinomas, whilst normal gastric epithelium either failed to stain or showed weak staining. Interestingly, S100A4 expression was more frequently observed in gastric cancer patients with advanced gastric cancer (p=0.039), positive lymph node metastasis (p=0.001), and peritoneal dissemination (p=0.022). No gene mutations were found in the analyzed genomic area in 77 gastric adenocarcinomas and 15 gastric cancer cell lines. We found one single nucleotide polymorphism without an amino acid change, A99G, in two cases. These data suggest that the overexpression of S100A4 may be closely related to the aggressiveness of gastric cancer in Korea. 相似文献
44.
The median raphe nucleus (MRN) is the primary source of serotonergic afferents to the limbic system that are generally considered to suppress hippocampal theta oscillations. GABA receptors are expressed in the MRN by serotonergic and nonserotonergic cells, including GABAergic and glutamatergic neurons. This study investigated the mechanisms by which the fluctuating GABA tone in the MRN leads to induction or suppression of hippocampal theta rhythm. We found that MRN application of the GABA(A) agonist muscimol (0.05-1.0 mM) or GABA(B) agonist baclofen (0.2 mM) by reverse microdialysis had strong theta promoting effects. The GABA(A) antagonist bicuculline infused in low concentrations (0.1, 0.2 mM) eliminated theta rhythm. A short period of theta activity of higher than normal frequency preceded hippocampal desynchronization in 46% of rats. Bicuculline in larger concentrations (0.5, 1.0, 2.0 mM) resulted in a biphasic response of an initial short (<10 min) hippocampal desynchronization followed by stable theta rhythm that lasted as long as the infusion continued. The frequency and amplitude of theta waves were higher than in control recordings and the oscillations showed a conspicuous intermittent character. Hippocampal theta rhythm elicited by MRN administration of bicuculline could be completely (0.5 mM bicuculline) or partially (1.0 mM bicuculline) blocked by simultaneous infusion of the GABA(B) antagonist CGP35348. Our findings suggest that the GABAergic network may have two opposing functions in the MRN: relieving the theta-generators from serotonergic inhibition and regulating the activity of a theta-promoting circuitry by the fluctuating GABA tone. The two mechanisms may be involved in different functions. 相似文献
45.
Seo JS Lee SY Won KJ Kim DJ Sohn DS Yang KM Cho SH Park JD Lee KH Kim HD 《Journal of Korean medical science》2000,15(6):641-646
We provided a curve-fit equation to predict the normal heart weight (g) in Koreans by examining 422 autopsies (215 males and 207 females, from newborn to age 77 yr) who were relatively in good general condition. Heart weight was well correlated with body surface area (m2), body weight (kg), and body height (cm) but poorly with age in both sex. Heart weight progressively increased from birth to the earlier 3rd and 4th decades in male and female, respectively, and then gradually decreased; mean heart weight of all age group was greater in male than in female and significantly different from birth to 4th decade. In both sex, heart weight exponentially increased in accordance with the increase of body height, body weight, and body surface (in male, heart weight=0.00312 x body height(2.239), r2=0.750, p<0.0001; in female, heart weight=0.00443 x body height(2170), r2=0.781, p<0.0001; in male, heart weight=9.22 x body weight(0.853), r2=0.770, p<0.0001; in female, heart weight=9.00 x body weight0.855, r2=0.820, p<0.0001; in male, heart weight=155.18 x body surface area1.290, r=0.808, p<0.0001; in female, heart weight=124.13 x body surface area1.242, r=0.834, p<0.0001). These results indicate that heart weight is better correlated with body surface area than with body weight; however, body weight should be a better determinant of a predicted heart weight, since body surface area is entirely dependent on body height and body weight. 相似文献
46.
Kim HS Lee SH Lee JW Soung YH Lee JH Park JY Cho YG Kim CJ Kim SY Lee YS Park WS Kim SH Lee JY Yoo NJ 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2003,111(4):490-491
Among the systems triggering apoptosis, the Fas-Fas ligand (FasL) system is recognized as a major pathway for the induction of apoptosis in cells and tissues. Ligation of Fas by either an agonistic antibody or FasL transmits a 'death signal' to the target cell, potentially triggering apoptosis. Alterations of genes along the Fas-mediated apoptosis pathway have been reported in many human cancers. However, there have been no data regarding FasL gene mutations in human cancers. We hypothesized that FasL gene mutation might be involved in the development of non-Hodgkin lymphoma (NHL). In this study, we analyzed the entire coding region of the FasL gene for the detection of somatic mutations in a series of 111 NHLs and found that one tumor had a FasL gene mutation in the cytoplasmic domain. To evaluate the functional alterations of the mutant in apoptosis, we overexpressed the mutant in 293T cells, but couldn't find any significant loss of cell death compared to the wild-type FasL. Together, these data suggest that FasL is occasionally mutated in human NHL and that FasL mutations appear to play no role in the pathogenesis of the vast majority of NHLs. 相似文献
47.
Nonspecific induction of immunoglobulin M antibodies to periodontal disease-associated microorganisms after polyclonal human B-lymphocyte activation by Fusobacterium nucleatum. 总被引:1,自引:3,他引:1 下载免费PDF全文
The production of antibodies to oral bacteria was determined in lymphocyte cultures stimulated with sonicated Fusobacterium nucleatum, a potent inducer of polyclonal B-cell activation. After 9 days the cultures were examined by a microenzyme-linked immunosorbent assay for immunoglobulin M (IgM) antibodies to F. nucleatum, Bacteroides gingivalis, Actinomyces viscosus, and Streptococcus sanguis. Antibodies to these four bacteria were detected in cultures stimulated with polyclonal B-cell activation-inducing concentrations of F. nucleatum. However, significant concentrations of antibodies to F. nucleatum, but not to the other three microorganisms, were produced in cultures that received suboptimal polyclonal B-cell activation-inducing doses of F. nucleatum. Absorption studies indicated the specificity of the antibodies to each of the bacteria tested. IgM antibody production induced by F. nucleatum was enhanced by the addition of T cells. The production of IgM antibodies to the bacteria was reproducible in cultures from a single person tested on 3 consecutive days. The concentration of antibodies in replicate cultures, however, fluctuated greatly. To obtain consistent responses on successive days, multiple replicate cultures were required. These results suggest that F. nucleatum, which is frequently present in subgingival plaque, could induce the production of antibodies not only to F. nucleatum, but also to other microorganisms associated with periodontal diseases. 相似文献
48.
Lithium chloride (LiCl) at doses sufficient to induce conditioned taste aversion (CTA) causes c-Fos expression in the relevant brain regions and activates the hypothalamic-pituitary-adrenal (HPA) axis. It has been suggested that nitric oxide (NO) in the central nervous system may play a role not only in the activation of HPA axis but also in CTA learning, and that LiCl may activate the brain NO system. To determine the role of NO in lithium-induced CTA, we examined the lithium-induced CTA, brain c-Fos expression, and plasma corticosterone level with Nomega-nitro-L-arginine methyl ester (L-NAME) pretreatment. Intraperitoneal L-NAME (30 mg/kg) given 30 min prior to LiCl significantly decreased lithium-induced c-Fos expression in the brain regions implicated in CTA learning, such as the hypothalamic paraventricular nucleus (PVN), central nucleus of amygdala (CeA), and nucleus tractus of solitarius. However, either the lithium-induced CTA acquisition or the increase in plasma corticosterone was not attenuated by l-NAME pretreatment. These results suggest that NO may be involved in lithium-induced neuronal activation of the brain regions, but not in the CTA acquisition or the HPA axis activation. 相似文献
49.
Kim HK Jin SY Lee NS Won JH Park HS Yang WI 《Archives of pathology & laboratory medicine》2004,128(8):e96-e99
An anaplastic large cell lymphoma that was negative for Epstein-Barr virus and positive for Ki-1 (CD30) presented as a polypoid scalp mass in a 56-year-old man 16 years after renal transplantation. The lymphoma was of the CD4+ cytotoxic T-cell lineage, and the tumor cells also expressed CD56. Despite reduction in the dose of immunosuppression and localized radiotherapy, the tumor had rapidly progressed to involve the soft tissue of the right hand. Systemic chemotherapy induced complete regression of the soft tissue lesion. This case illustrates that posttransplant primary cutaneous CD30+ anaplastic large cell lymphomas may assume an aggressive clinical course but can still be controlled by systemic chemotherapy. 相似文献
50.
The immunity of a combined DNA vaccine of HSV-2 glycoproteins B2 (gB2) and D2 (gD2) genes in comparison to individual vaccines was studied with regard to protecting against the HSV infection. Two recombinant DNA vaccines of the pHS2-gB2 or pHS2-gD2 were constructed and formulated. The neutralizing antibody titers appeared higher in the B2:D2 gene cocktail-vaccinated mice than that of the individual B2 or D2 gene-vaccinated group alone, and the positive KOS control induced higher titer of the neutralizing antibody than combined or individual gene vaccines. The mock-immunized mice failed to induce enough. The ranks for the CTL activity and the protection rates against the lethal intravaginal challenge were shown as KOS>B2:D2 cocktail>D2>B2 gene vaccines. The vaginal external diseases in the B2:D2 or D-vaccinated mice were significantly reduced against the challenging dosages. The virus titers in the vaginal secretions of the vaccinated mice significantly reduced with time, and the B2:D2 gene vaccine decreased more than each individual vaccine alone. It can be concluded that the cocktailed vaccines are more effective in the humoral and cellular immune responses in the mice, and in the protection of the mice against the intravaginal challenging dosages when compared with individual gene vaccines. All the DNA vaccines failed to block the latent infection in sensory nerves. 相似文献