全文获取类型
收费全文 | 123297篇 |
免费 | 8116篇 |
国内免费 | 539篇 |
专业分类
耳鼻咽喉 | 1313篇 |
儿科学 | 3632篇 |
妇产科学 | 2062篇 |
基础医学 | 16386篇 |
口腔科学 | 2205篇 |
临床医学 | 12188篇 |
内科学 | 26109篇 |
皮肤病学 | 1479篇 |
神经病学 | 11959篇 |
特种医学 | 3814篇 |
外国民族医学 | 1篇 |
外科学 | 17752篇 |
综合类 | 1660篇 |
现状与发展 | 1篇 |
一般理论 | 156篇 |
预防医学 | 10746篇 |
眼科学 | 3319篇 |
药学 | 8722篇 |
1篇 | |
中国医学 | 278篇 |
肿瘤学 | 8169篇 |
出版年
2023年 | 610篇 |
2022年 | 1064篇 |
2021年 | 2371篇 |
2020年 | 1418篇 |
2019年 | 2401篇 |
2018年 | 2808篇 |
2017年 | 2041篇 |
2016年 | 2383篇 |
2015年 | 2746篇 |
2014年 | 3965篇 |
2013年 | 5561篇 |
2012年 | 8471篇 |
2011年 | 9102篇 |
2010年 | 4968篇 |
2009年 | 4639篇 |
2008年 | 8026篇 |
2007年 | 8514篇 |
2006年 | 8071篇 |
2005年 | 8122篇 |
2004年 | 7667篇 |
2003年 | 7067篇 |
2002年 | 6816篇 |
2001年 | 1195篇 |
2000年 | 892篇 |
1999年 | 1229篇 |
1998年 | 1452篇 |
1997年 | 1227篇 |
1996年 | 955篇 |
1995年 | 947篇 |
1994年 | 800篇 |
1993年 | 786篇 |
1992年 | 664篇 |
1991年 | 609篇 |
1990年 | 540篇 |
1989年 | 501篇 |
1988年 | 502篇 |
1987年 | 484篇 |
1986年 | 419篇 |
1985年 | 497篇 |
1984年 | 562篇 |
1983年 | 522篇 |
1982年 | 697篇 |
1981年 | 610篇 |
1980年 | 534篇 |
1979年 | 369篇 |
1978年 | 347篇 |
1977年 | 348篇 |
1976年 | 291篇 |
1975年 | 272篇 |
1974年 | 279篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Yew Kuang Cheng Paul A Decker Megan M O'Byrne Catherine R Weiler 《Annals of allergy, asthma & immunology》2006,97(3):306-311
BACKGROUND: There are limited studies of large cohorts of patients with specific polysaccharide antibody deficiency (SPAD) syndrome. OBJECTIVE: To study the clinical and laboratory characteristics of patients with specific polysaccharide antibody deficiency syndrome. METHODS: We retrospectively studied 75 patients with total IgG levels of at least 500 mg/dL and fewer than 9 of 12 responses to vaccination with pneumococcal vaccine polyvalent. Exclusion criteria included an IgG level less than 500 mg/dL, established immunodeficiency syndrome, and secondary immunodeficiency. RESULTS: The most common clinical presentation was frequent infections (n = 69; 92%), including sinusitis (n = 53; 77%), pneumonia (n = 29; 42%), ear infections (n = 18; 26%), and bronchitis (n = 19; 28%). Other presentations were systemic infections (n = 5; 7%), autoimmune or rheumatic diseases (n = 6; 8%), and chronic diarrhea (n = 4; 5%). The median IgG2 level of patients with no response to pneumococcal vaccine polyvalent tended to be lower than that of patients with at least 1 response (150 vs 193 mg/dL, respectively; P = .06). There was no association between total IgG level (categorized as 500-600 or > or = 600 mg/dL) and frequency of infection (P = .43). Patients with fewer responses to pneumococcal vaccine polyvalent and a higher frequency of infections were more likely to receive intravenous immunoglobulin (IVIG) therapy (P = .01 and .003, respectively). Treatment with IVIG significantly reduced the number of infections (P < .001). CONCLUSION: Patients with no response to pneumococcal vaccine polyvalent tended to have lower IgG2 levels; those with fewer responses were more likely to receive IVIG therapy. 相似文献
92.
Paul Wan Sia Heng Tin Wui Wong Wai See Cheong 《European journal of pharmaceutical sciences》2003,19(5):381-393
The melt agglomeration process of lactose powder with hydrogenated cottonseed oil (HCO) as the hydrophobic meltable binder was investigated by studying the physicochemical properties of molten HCO modified by sucrose stearates S170, S770 and S1570. The size, size distribution, micromeritic and adhesion properties of agglomerates as well as surface tension, contact angle, viscosity and specific volume of molten HCO, with and without sucrose stearates, were examined. The viscosity, specific volume and surface tension of molten HCO were found to be modified to varying extents by sucrose stearates which are available in different HLB values and melt properties. The growth of melt agglomerates was promoted predominantly by an increase in viscosity, an increase in specific volume or a decrease in surface tension of the molten binding liquid. The agglomerate growth propensity was higher with an increase in inter-particulate binding strength, agglomerate surface wetness and extent of agglomerate consolidation which enhanced the liquid migration from agglomerate core to periphery leading to an increased surface plasticity for coalescence. The inclusion of high concentrations of completely meltable sucrose stearate S170 greatly induced the growth of agglomerates through increased specific volume and viscosity of the molten binding liquid. On the other hand, the inclusion of incompletely meltable sucrose stearates S770 and S1570 promoted the agglomeration mainly via the reduction in surface tension of the molten binding liquid with declining agglomerate growth propensity at high sucrose stearate concentrations. In addition to being an agglomeration modifier, sucrose stearate demonstrated anti-adherent property in melt agglomeration process. The properties of molten HCO and melt agglomerates were dependent on the type and concentration of sucrose stearate added. 相似文献
93.
Julie Albietz Paul Sanfilippo Robyn Troutbeck Lee M Lenton 《Optometry and vision science》2003,80(6):420-430
PURPOSE: To review the incidence, underlying pathophysiology, and clinical features of filamentary keratitis and to identify evidence-based best-practice strategies for managing filamentary keratitis. METHODS: A comprehensive review of published literature was undertaken. Recommendations for best-practice management strategies were based on the available evidence. Three cases are presented to illustrate the clinical findings and management of patients with chronic filamentary keratitis. RESULTS: Although the evidence base is limited by the absence of well-designed studies, current evidence indicates the following: (1) Aqueous-deficient dry eye (keratoconjunctivitis sicca) is the most common ocular condition associated with filamentary keratitis. (2) Current best-practice management of filamentary keratitis involves treating the underlying dry eye and specific treatments for the corneal filaments. Proposed treatments include nonpreserved lubricants, topical steroidal and nonsteroidal anti-inflammatory agents, and punctal plugs for aqueous-deficient dry eye as well as mechanical removal of filaments, hypertonic saline, mucolytic agents, and bandage contact lenses for the filaments. (3) Filamentary keratitis can be induced or exacerbated by contact lens wear and ocular surgical procedures such as cataract surgery and corneal graft surgery. Pre- and postoperative ocular surface management strategies should be considered in the surgical planning of patients with, or who are susceptible to, filamentary keratitis. Filamentary keratitis can also be induced and/or exacerbated by chronic use of ocular and/or systemic medications, and alternate medications or additional measures to manage the tear film and ocular surface may be required in these cases. CONCLUSIONS: Filamentary keratitis can be a chronic, recurrent, and debilitating condition. With a systemic approach to diagnosis and management, the condition can be effectively controlled and the incidence and severity of recurrences minimized. 相似文献
94.
Liposome-mediated transfer of vascular endothelial growth factor cDNA augments survival of random-pattern skin flaps in the rat. 总被引:6,自引:0,他引:6
Paul Y Liu Wenjing Tong Kan Liu Sang Hoon Han Xiao Tian Wang Evangelos Badiavas Kimberly Rieger-Christ Ian Summerhayes 《Wound repair and regeneration》2004,12(1):80-85
Tissue engineering is an application for gene therapy that is in its infancy. We show that simple liposomal-mediated gene transfer could result in a potentially useful biological effect in the field of wound healing. cDNA encoding the 165 amino acid form of vascular endothelial growth factor complexed to commercially available liposomes was injected into rat skin 1 week before raising a random pattern 3 x 10 cm flap. The flap survival was enhanced by 14 percent, and was accomplished without accessing the arterial inflow of the territory. These results were statistically significant (p<0.002) and reproducible. No adverse effects were seen. Histological analysis of the angiogenesis localized much of the new vessel formation to the area around the hair follicles. Polymerase chain reaction amplification of extracted flap tissue confirmed the presence of the transgene. 相似文献
95.
In certain Japanese macaque (Macaca fuscata) populations, females routinely engage in same-sex courtship, mounting, and consortship activity. Drawing on behavioral,
biogeographic, and genetic research, we suggest that female homosexual behavior may be associated with genetically distinct
free-ranging populations of Japanese macaques. In addition, we briefly discuss the implications of this research for the evolution
of female homosexual behavior in this species. 相似文献
96.
97.
98.
99.
Christian J. Sauder Cheryl X. Zhang Malen A. Link W. Paul Duprex Kathryn M. Carbone Steven A. Rubin 《Vaccine》2009
The recent global resurgence of mumps has drawn attention to the continued need for robust mumps immunization programs. Unfortunately, some vaccines derived from inadequately attenuated vaccine strains of mumps virus have caused meningitis in vaccinees, leading to withdrawal of certain vaccine strains from the market, public resistance to vaccination, or in some cases, cessation of national mumps vaccination programs. The most widely implicated mumps vaccine in cases of postvaccination meningitis is derived from the Urabe AM9 strain, which remains in use in some countries. The Urabe AM9 vaccine virus has been shown to exhibit a considerable degree of nucleotide and amino acid heterogeneity. Some studies have specifically implicated variants containing a lysine residue at amino acid position 335 in the hemagglutinin-neuraminidase (HN) protein with neurotoxicity, whereas a glutamic acid residue at this position was associated with attenuation. To test this hypothesis we generated two modified Urabe AM9 cDNA clones coding either for a lysine or a glutamic acid at position 335 in the HN gene. The two viruses were rescued by reverse genetics and characterized in vitro and in vivo. Both viruses exhibited similar growth kinetics in neuronal and non-neuronal cell lines and were of similar neurotoxicity when tested in rats, suggesting that amino acid 335 is not a crucial determinant of Urabe AM9 growth or neurovirulence. 相似文献
100.
Histopathological characterisation of effects of the mouse Pax6 missense mutation on eye development
Thaya Ramaesh Steven E. Williams Catriona Paul Kanna Ramaesh John D. West 《Experimental eye research》2009,89(2):263-273
Mutations in PAX6/Pax6 lead to a variety of ocular anomalies in humans and mice. The aim of the study was to characterise the ocular abnormalities caused by the missense Pax6Leca4 mutation and compare them to published observations on Pax6 alleles that are functionally equivalent to Pax6− null alleles (such as Pax6Sey and Pax6Sey-Neu) and human inherited eye diseases. Ocular features of homozygous Pax6Leca4/Leca4 and heterozygous Pax6Leca4/+ embryos at E12.5-E18.5, heterozygous Pax6Leca4/+ young mice at P18 and heterozygous Pax6Leca4/+ adults at 12 weeks were analysed histologically with their wild-type Pax6+/+ littermates. Homozygous Pax6Leca4/Leca4 fetuses died perinatally with no eyes although an optic cup rudiment with pigmented cells developed. Pax6Leca4/+ mice were microphthalmic and a range of other severe ocular phenotypes affected both the anterior and the posterior segments. In contrast to Pax6+/−, the Pax6Leca4/+ eyes had no goblet cells in the corneal epithelium, the iris was not hypoplastic and there was no lens-corneal epithelial plug. However, microphthalmia was more severe, corneal vascularisation occurred earlier (during fetal stages), pigmented cells were present in the vitreous and corneal stroma and the ciliary body was malformed or abnormal. These results show that, although Pax6Leca4/+ lacked some eye abnormalities commonly seen in Pax6Sey/+ and Pax6Sey-Neu/+ eyes, in most respects their eyes were more severely affected. These differences probably reflect both differences between the Pax6Leca4 and the Pax6Sey-Neu mutations and differences in modifier gene expression in different genetic backgrounds. The presence of pigmented cells in the cornea is a novel observation. Some Pax6Leca4/+ ocular abnormalities were similar to those present in human Peters' anomaly and persistent hyperplastic primary vitreous (PHPV) so Pax6Leca4/+ mice provide a useful model for some inherited eye diseases. 相似文献