全文获取类型
收费全文 | 24455篇 |
免费 | 1419篇 |
国内免费 | 100篇 |
专业分类
耳鼻咽喉 | 275篇 |
儿科学 | 773篇 |
妇产科学 | 461篇 |
基础医学 | 3389篇 |
口腔科学 | 751篇 |
临床医学 | 1944篇 |
内科学 | 6284篇 |
皮肤病学 | 829篇 |
神经病学 | 2040篇 |
特种医学 | 371篇 |
外科学 | 2329篇 |
综合类 | 138篇 |
一般理论 | 11篇 |
预防医学 | 2664篇 |
眼科学 | 356篇 |
药学 | 1902篇 |
中国医学 | 127篇 |
肿瘤学 | 1330篇 |
出版年
2024年 | 23篇 |
2023年 | 253篇 |
2022年 | 155篇 |
2021年 | 767篇 |
2020年 | 387篇 |
2019年 | 827篇 |
2018年 | 1283篇 |
2017年 | 730篇 |
2016年 | 682篇 |
2015年 | 811篇 |
2014年 | 843篇 |
2013年 | 1184篇 |
2012年 | 2247篇 |
2011年 | 2279篇 |
2010年 | 1126篇 |
2009年 | 807篇 |
2008年 | 1678篇 |
2007年 | 1685篇 |
2006年 | 1577篇 |
2005年 | 1582篇 |
2004年 | 1364篇 |
2003年 | 1191篇 |
2002年 | 1073篇 |
2001年 | 200篇 |
2000年 | 201篇 |
1999年 | 163篇 |
1998年 | 60篇 |
1997年 | 39篇 |
1996年 | 44篇 |
1995年 | 41篇 |
1994年 | 32篇 |
1993年 | 20篇 |
1992年 | 69篇 |
1991年 | 58篇 |
1990年 | 43篇 |
1989年 | 45篇 |
1988年 | 46篇 |
1987年 | 38篇 |
1986年 | 41篇 |
1985年 | 37篇 |
1984年 | 27篇 |
1983年 | 23篇 |
1982年 | 18篇 |
1980年 | 20篇 |
1979年 | 19篇 |
1978年 | 12篇 |
1976年 | 10篇 |
1975年 | 11篇 |
1974年 | 19篇 |
1971年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Southern analysis with rpl5 and rps14 mtDNA gene probes of Solanum tuberosum, S. commersonii and a sample of somatic hybrids detected polymorphisms between parents and the appearance of a novel restriction fragment in various hybrids. In one of them, detailed mtDNA analyses revealed various configurations of the rpl5–rps14 region present at different stoichiometries. Multiple inter-parental recombination events across homologous sequences were assumed to have caused these rearrangements. Sequence similarity searches detected one sequence putatively involved in the recombination upstream of the rpl5 gene. The presence of a second recombinogenic sequence was inferred. We propose two models to explain the mechanism responsible for obtaining the different rpl5–rps14 arrangements shown after somatic hybridization. Variability in the rpl5–rps14 region observed in both the parental species and their somatic hybrids suggests this region is a hot spot for mtDNA rearrangements in Solanum spp.Contribution no. 39 from the Institute of Plant Genetics, Research Division of Portici.Communicated by A. Brennicke 相似文献
63.
Blümel JE Castelo-Branco C Kerrigan N Cancelo MJ Blümel B Haya J Flores M Carvajal MC Sarrá S 《Menopause (New York, N.Y.)》2003,10(3):235-240
OBJECTIVE: To assess the beliefs of climacteric women regarding their health, menopause, and hormone replacement therapy (HRT). DESIGN: Medical students asked to interview 526 healthy women, ranging from 40 to 64 years of age, between January and February of 2002. Of that number, 26 (4.9%) declined to participate in the interview. Thus, 500 women were interviewed about their beliefs and perceptions regarding their quality of life and health risks, as well as their opinions on menopause and HRT. RESULTS: The mean age of the sample was 53.3 +/- 6.2 years; 83.4% were postmenopausal, and 18.8% were HRT users. Of the women interviewed, 38.6% believed that their health was good. Although 78.8% thought that cancer is the main cause of death, 64% of them considered themselves to be at high risk for cardiovascular disease and osteoporosis. Most (64%) believed that menopause deteriorates the quality of life and that it increases cardiovascular risk (52.4%) and osteoporosis (72.0%). The HRT users perceived that they had better health status (48.9% v 36.2%, P < 0.02) and smaller cardiovascular risk (54.3% v 66.3%, P < 0.04) than did the nonusers; however, they ignored the preventive effect of estrogens in osteoporosis. CONCLUSIONS: Women believe that menopause deteriorates their health. The HRT users perceived themselves to be healthier and to have a smaller risk for cardiovascular disease. 相似文献
64.
B Hédon P Marès C Humeau G Garcia O Flandre B Galand F Arnal P Cristol F Deschamps 《Annales de biologie clinique》1985,43(1):1-5
In vitro fertilization (IVF) and embryo transfer (ET) appear to constitute a revolution in the reproductive sciences rather than merely a new technique in the treatment of sterility. Principle of IVF: IVF accomplishes in vitro the process than normally occurs in the oviduct between the ovulation of oocyte II and embryo implantation in the endometrium. This 4 day period (under normal conditions in the woman) involves 4 steps: recovery, fertilization, segmentation and transport. Performance of IVF: Recovery of the oocytes: The oocytes are recovered under celioscopic or echographic observation when they have completed cytoplasmic maturation and their first meiosis. A precise monitoring of ovulation (spontaneous or induced) should be performed using estrogen and LH assays. IVF provides an opportunity for evaluating the methods of ovulation induction and monitoring, as a function of the maturation of the oocytes recovered. Fertilization: When the oocyte has achieved maturing after several hours of incubation, fertilization is obtained 15 h contact with washed and capacitated spermatozoa (100 000/ml). This step is highly dependent on gametocyte quality: oocyte maturity and fecundity of spermatozoa, which can be estimated from the percentage of survival in the insemination medium. Segmentation occurs in culture at pH 7.28 in the presence of 5 per cent CO2 at 37 degrees C (pronucleus 15th, 2 blastomeres 26 h, 4-8 blastomeres 52 h). Embryo transfer is carried out when an embryo is present at 52 h. Only 1/10 of the embryo transfers result in successful implantation, which depends on the quality of the embryo; the quality can only be indirect criteria.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
65.
P. Gilon Y. Miura J. C. Henquin J. Tytgat P. Daenens V. Decostre G. Maréchal S. M. Brichard D. J. Becker B. Reul L. N. Ongemba V. Rousseau W. Eechaute W. Dhooghe P. Calders N. C. Gao E. Lacroix J. Weyne J. Kaufman S. Tomasovic F. Frankenne A. Boland D. Delapierre D. Marechal A. Dresse O. Feron M. Wibo M. Maleki L. Zheng F. Kolar T. Godfraind K. Paemeleire L. Leybaert C. Lambillotte M. Nenquin E. Wechsung A. Houvenaghel G. Mancuso E. Tirelli S. Vandenput D. Votion D. H. Duvivier T. Art P. Lekeux H. D. Duvivier B. S. Kelemen E. Van Erck I. Mountian L. Missiaen W. Van Driessche 《Pflügers Archiv : European journal of physiology》1996,432(4):R139-R144
66.
Human TLR-7-, -8-, and -9-mediated induction of IFN-alpha/beta and -lambda Is IRAK-4 dependent and redundant for protective immunity to viruses 总被引:12,自引:0,他引:12
Yang K Puel A Zhang S Eidenschenk C Ku CL Casrouge A Picard C von Bernuth H Senechal B Plancoulaine S Al-Hajjar S Al-Ghonaium A Maródi L Davidson D Speert D Roifman C Garty BZ Ozinsky A Barrat FJ Coffman RL Miller RL Li X Lebon P Rodriguez-Gallego C Chapel H Geissmann F Jouanguy E Casanova JL 《Immunity》2005,23(5):465-478
Five TLRs are thought to play an important role in antiviral immunity, sensing viral products and inducing IFN-alpha/beta and -lambda. Surprisingly, patients with a defect of IRAK-4, a critical kinase downstream from TLRs, are resistant to common viruses. We show here that IFN-alpha/beta and -lambda induction via TLR-7, TLR-8, and TLR-9 was abolished in IRAK-4-deficient blood cells. In contrast, IFN-alpha/beta and -lambda were induced normally by TLR-3 and TLR-4 agonists. Moreover, IFN-beta and -lambda were normally induced by TLR-3 agonists and viruses in IRAK-4-deficient fibroblasts. We further show that IFN-alpha/beta and -lambda production in response to 9 of 11 viruses tested was normal or weakly affected in IRAK-4-deficient blood cells. Thus, IRAK-4-deficient patients may control viral infections by TLR-3- and TLR-4-dependent and/or TLR-independent production of IFNs. The TLR-7-, TLR-8-, and TLR-9-dependent induction of IFN-alpha/beta and -lambda is strictly IRAK-4 dependent and paradoxically redundant for protective immunity to most viruses in humans. 相似文献
67.
68.
Marruchella G Di Leonardo M Di Guardo G Romanucci M Marà M G Tiscar P Mosca F Della Salda L 《Journal of comparative pathology》2004,131(1):10-17
Heat shock proteins (HSPs), known to play a key role in cellular homeostasis, may also play a role in the defensive mechanisms of gastric mucosa. By means of appropriate immunohistochemical and immunobiochemical techniques, the expression of HSP27, HSP72 and HSP73 within the epithelium of normal and pre-ulcerative (hyperkeratinized) mucosa of the pars oesophagea of abattoir pigs was assessed. In normal mucosa, HSP72 and HSP73 expression was mainly limited to the basal epithelial cell layer, whereas HSP27 expression was consistently detected within the superficial epithelial cell layers. In hyperkeratinized mucosa, HSP72 and HSP73 immunoreactivity appeared to be more widespread, becoming very intense within epithelial cells affected by hydropic degeneration. Hyperkeratinized mucosa also showed HSP27 immunoreactivity, which was particularly intense in epithelial areas affected by hydropic degeneration. Western blot analysis confirmed HSP27, HSP72 and HSP73 expression in normal and in pre-ulcerative mucosa of the pars oesophagea. Semi-quantitative analysis showed that for all three HSPs the immunoreactivity was more intense in pre-ulcerative mucosa than in normal mucosa. The different expression patterns observed may have functional significance; further studies are needed, however, to define the role of HSPs in swine oesophagogastric lesions, the aetiology and pathogenesis of which are largely unknown. 相似文献
69.
70.
González N Sancho V Martín-Duce A Tornero-Esteban P Valverde I Malaisse WJ Villanueva-Peñacarrillo ML 《International journal of molecular medicine》2005,16(4):747-752
Changes in the activity of glycogen synthase a and related kinases (phosphatidylinositol-3-kinase, protein kinase B, p44/42 MAP kinases and p70s6 kinase) evoked by GLP-1 in human myocytes from normal subjects were recently implied in the effect of this hormone upon D-glucose transport and glycogen synthesis in the same cells. The major aims of the present study were i) to investigate the possible extension of this knowledge to myocytes obtained from type 2 diabetic patients, ii) to compare in these patients the response to GLP-1, insulin or the structurally related GLP-1 peptides, exendin (1-39)amide and exendin(9-39)amide, and iii) to explore possible differences in the responsiveness to these agents between normal and diabetic subjects. Apart from the much higher basal PI3K activity and impaired response to insulin of p44/42 MAP kinases in the diabetic patients, the changes in enzyme activity caused by either hormone or peptide, although not identical, were essentially comparable. Nevertheless, significant differences in glucose transport and metabolism parameters were observed in the diabetic patients vs. normal subjects: in the diabetic patients, basal 2-deoxy-glucose uptake and glycogen synthase a activity were lower, accompanied by a similar increasing effect of GLP-1 or insulin; yet, the basal value for glycogen synthesis was higher, coinciding with a lesser relative increment in response to GLP-1 or insulin. 相似文献