全文获取类型
收费全文 | 25456篇 |
免费 | 1355篇 |
国内免费 | 137篇 |
专业分类
耳鼻咽喉 | 190篇 |
儿科学 | 647篇 |
妇产科学 | 452篇 |
基础医学 | 3188篇 |
口腔科学 | 682篇 |
临床医学 | 1746篇 |
内科学 | 6451篇 |
皮肤病学 | 584篇 |
神经病学 | 2229篇 |
特种医学 | 872篇 |
外科学 | 3783篇 |
综合类 | 139篇 |
一般理论 | 4篇 |
预防医学 | 756篇 |
眼科学 | 393篇 |
药学 | 1925篇 |
中国医学 | 35篇 |
肿瘤学 | 2872篇 |
出版年
2023年 | 161篇 |
2022年 | 294篇 |
2021年 | 506篇 |
2020年 | 278篇 |
2019年 | 370篇 |
2018年 | 506篇 |
2017年 | 372篇 |
2016年 | 447篇 |
2015年 | 508篇 |
2014年 | 631篇 |
2013年 | 767篇 |
2012年 | 1154篇 |
2011年 | 1271篇 |
2010年 | 724篇 |
2009年 | 632篇 |
2008年 | 1081篇 |
2007年 | 1246篇 |
2006年 | 1167篇 |
2005年 | 1183篇 |
2004年 | 1120篇 |
2003年 | 1048篇 |
2002年 | 1061篇 |
2001年 | 958篇 |
2000年 | 928篇 |
1999年 | 873篇 |
1998年 | 305篇 |
1997年 | 241篇 |
1996年 | 280篇 |
1995年 | 170篇 |
1994年 | 166篇 |
1993年 | 149篇 |
1992年 | 540篇 |
1991年 | 501篇 |
1990年 | 510篇 |
1989年 | 464篇 |
1988年 | 438篇 |
1987年 | 436篇 |
1986年 | 379篇 |
1985年 | 395篇 |
1984年 | 280篇 |
1983年 | 190篇 |
1979年 | 214篇 |
1978年 | 142篇 |
1977年 | 139篇 |
1974年 | 130篇 |
1971年 | 136篇 |
1970年 | 132篇 |
1969年 | 128篇 |
1968年 | 141篇 |
1967年 | 141篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Alternating current stimulation of the eye generates an occipital electrically evoked response (a.c.-e.e.r.) of which the frequency characteristic shows a monophasic pattern for which the optimum stimulus frequency for evoking a maximum response is 18 Hz. A.C.-E.E.R. is a very useful tool for making a diagnosis of pigmentary retinal dystrophy and is different from the e.r.g. in that it is not affected by diseases of the optical system such as strong refractive anomalies or vitreous opacities. 相似文献
102.
Kinetic profiles of sequential gene expressions for chemokines in mice with contact hypersensitivity
Using cDNA microarray technology, the expression of chemokine genes in the elicitation site of 2,4,6-trinitrochlorobenzene-induced contact hypersensitivity (CHS) was examined in mice. Of the 33 genes analyzed, levels of 11 gene expressions changed, and these can be assigned to four groups based on their kinetic patterns; (1) LARC/CCL20 whose mRNA level increased rapidly at 3 h post-challenge and then gradually decreased, (2) JE/CCL2, MARC/CCL7, MIP-1gamma/CCL9, monocyte chemoattractant protein (MCP)-5/CCL12, ELC/CCL19 and BRAK/CXCL14 whose mRNA levels increased with time and reached the maximum at 6-9 h post-challenge, (3) LIX/CXCL5, Mig/CXCL9 and IP-10/CXCL10 whose mRNA levels increased gradually at least up to 12 h post challenge, and (4) SLC/CCL21 whose mRNA level decreased gradually with time after challenge. The findings suggest that sequential expression of chemokine genes is essential for orientating non-specific skin response to hapten-specific CHS response through the recruitment of inflammatory cells such as neutrophils, monocytes/macrophages and T-cells from the circulation into the tissue site. 相似文献
103.
104.
105.
106.
107.
A synthesis of psychological interventions for the bereaved 总被引:1,自引:0,他引:1
Several interventions have been implemented to address the adverse psychological and physical consequences associated with bereavement. In this review, we summarize four major theories of bereavement, present a qualitative review of bereavement intervention studies, and assess the overall effectiveness of bereavement intervention studies in a quantitative meta-analysis. Summaries of the theories are drawn from published theoretical works. The qualitative and quantitative reviews were based on searches of Medline, PsychINFO, and Dissertation Abstracts International databases using the keywords "bereaved" and "bereavement." Overall, the interventions were largely methodologically flawed, rarely specified what theory of bereavement they were testing, and slowed surprisingly weak effect sizes. Possible interpretations for the small effect sizes are discussed, and future directions are outlined. 相似文献
108.
Hirata T Iida A Shiraki-Iida T Kitazato K Kato A Nagai Y Hasegawa M 《Journal of virological methods》2002,104(2):125-133
An improved system is described to recover non-transmissible Sendai virus that lack the envelope fusion (F) gene from cloned cDNA. The system (1) used plasmids that expressed the F and the HN viral envelope proteins, as well as the plasmids that expressed the viral NP, P, and L proteins as helper plasmids for recovery, and (2) overlaid packaging cells that expressed the F protein. With this improved system, we have succeeded in recovery of F-defective Sendai virus expressing two foreign proteins, and expression vectors that do not contain the EGFP reporter gene. This system may provide the basis for constructing recombinant F-defective Sendai virus for preventing and treating human diseases in the form of vaccines and vectors for gene therapy. 相似文献
109.
Nishimura H Tokuyama K Arakawa H Ohki Y Sato A Kato M Mochizuki H Morikawa A 《International archives of allergy and immunology》2002,129(4):320-326
BACKGROUND: Chronic exposure to fenoterol (FEN), a beta(2)-adrenergic receptor (beta(2)-AR) agonist, was shown to induce both airway hyperresponsiveness and airway remodeling in experimental animals. OBJECTIVE: We wanted to know the effects of chronic exposure to procaterol (PRO), a beta(2)-AR agonist, on airway function and structure, because this agent is widely used as a bronchodilator in Japan. For comparison, the effects of FEN were also examined. METHODS: Aerosolized PRO (0.1 or 1 mg/ml), FEN (1 mg/ml) or vehicle (0.9% NaCl) was given to guinea pigs 3 times a day for 6 weeks. Sublaryngeal deposition of these agents was calculated using radioisotopes. At 72 h after the last inhalation of PRO, FEN or vehicle, the dose-response relationship between lung resistance (R(L)) and intravenously administered acetylcholine (ACh) was measured. After measuring R(L), histological changes in noncartilaginous airway dimensions were evaluated. RESULTS: The amount of sublaryngeal deposition of 0.1 mg/ml PRO in the present study was speculated to be 100 times larger than that of therapeutic dose. ACh concentrations causing 2-fold, 10-fold and maximal increases in R(L) were not different in 4 groups tested. In the smaller membranous airways (<0.4 mm in diameter), but not the larger ones, thickening of adventitial areas was significantly greater in animals treated with beta(2)-AR agonists than in control animals (23 and 25, and 96% higher in animals treated with 0.1 and 1 mg/ml PRO or 1 mg/ml FEN, respectively). The degree of the increase was significantly less in PRO-treated animals than in FEN-treated animals (p < 0.01). CONCLUSION: Our results did not provide any evidence that regular inhalation of PRO at the therapeutic dose might induce bronchial hyperresponsiveness. In addition, huge amounts of PRO only caused a mild thickening of the adventitial areas, suggesting that PRO may be a weak inducer of airway remodeling compared with FEN. 相似文献
110.
Atsuo Murata Hitoshi Toda Ken -Ichi Uda Hirohito Hayashida Takeshi Kato Hidewaki Nakagawa Shigekazu Yokoyama Hideaki Morishita Toru Yamakawa Jiro Hirose Takesada Mori Nariaki Matsuura 《Inflammation》1994,18(4):337-347
Severe inflammatory responses after major surgeries, trauma, and infection develop multiple organ dysfunction. In the mechanisms of the pathogenesis of these responses, activated neutrophils are thought to be important in terms of their ability to produce various kinds of proteinases, which can degrade various proteins constructing human tissues. Among their proteinases, neutrophil elastase is the strongest serine proteinase secreted from activated neutrophils. Thus, we examined in this study the inhibitory effect and therapeutic efficacy of newly produced recombinant human Kunitz-type proteinase inhibitor (R-020), which coded the second domain of human urinary trypsin inhibitor. R-020 was effective in significantly improving the survival rate after induction of the rat lethal peritonitis model (cecal ligation and punctureinduced septic shock model). We suggest that various serine proteinases are implicated in the pathogenesis of neutrophil-related multiple organ failure and that recombinant human Kunitz-type proteinase inhibitor might be effective in the treatment of these kinds of organ dysfunction. 相似文献