全文获取类型
收费全文 | 103699篇 |
免费 | 11137篇 |
国内免费 | 6936篇 |
专业分类
耳鼻咽喉 | 1571篇 |
儿科学 | 1351篇 |
妇产科学 | 717篇 |
基础医学 | 8591篇 |
口腔科学 | 2362篇 |
临床医学 | 12922篇 |
内科学 | 10676篇 |
皮肤病学 | 1096篇 |
神经病学 | 3346篇 |
特种医学 | 4350篇 |
外国民族医学 | 28篇 |
外科学 | 9767篇 |
综合类 | 25384篇 |
现状与发展 | 29篇 |
一般理论 | 6篇 |
预防医学 | 9800篇 |
眼科学 | 1911篇 |
药学 | 11841篇 |
173篇 | |
中国医学 | 9255篇 |
肿瘤学 | 6596篇 |
出版年
2024年 | 549篇 |
2023年 | 1633篇 |
2022年 | 4280篇 |
2021年 | 5404篇 |
2020年 | 4506篇 |
2019年 | 3003篇 |
2018年 | 2982篇 |
2017年 | 3557篇 |
2016年 | 2937篇 |
2015年 | 4893篇 |
2014年 | 6110篇 |
2013年 | 6711篇 |
2012年 | 9917篇 |
2011年 | 10460篇 |
2010年 | 8279篇 |
2009年 | 7114篇 |
2008年 | 7739篇 |
2007年 | 6946篇 |
2006年 | 6021篇 |
2005年 | 4733篇 |
2004年 | 3269篇 |
2003年 | 2659篇 |
2002年 | 1994篇 |
2001年 | 1670篇 |
2000年 | 1357篇 |
1999年 | 825篇 |
1998年 | 370篇 |
1997年 | 325篇 |
1996年 | 302篇 |
1995年 | 242篇 |
1994年 | 185篇 |
1993年 | 131篇 |
1992年 | 109篇 |
1991年 | 106篇 |
1990年 | 89篇 |
1989年 | 73篇 |
1988年 | 52篇 |
1987年 | 58篇 |
1986年 | 45篇 |
1985年 | 40篇 |
1984年 | 8篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1965年 | 5篇 |
1959年 | 4篇 |
1958年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
急进性后极部早产儿视网膜病变的临床进程及疗效观察 总被引:1,自引:0,他引:1
目的 描述急进性后极部早产儿视网膜病变(AP-ROP)的临床进程及特征,评价视网膜光凝及冷凝对急进性后极部早产儿视网膜病变的治疗效果.方法 前瞻性、非对比性、连续性病例.2006年1月至2008年6月经检查确诊为急进性后极部ROP的患儿8例16只眼.确诊后24h内行间接眼底镜下行视网膜光凝治疗联合或不联合直视下冷凝治疗.结果 急进性后极部早产儿视网膜病变以病变大部分位于后极部1区,所有象限视网膜血管扩张迂曲,病程进展快,若不及时治疗,迅速发生视网膜漏斗状全脱离为临床特征.本组8例16只眼视网膜光凝和(或)冷凝治疗后,9只眼病变完全退化或控制,占56.2%.7只眼病情未能控制,最终发展为4b至5期视网膜病变.结论 AP-ROP进展快,预后不良,部分患儿虽经严密观察和治疗,病情仍进展.视网膜光凝和(或)冷凝治疗能控制大部分AP-ROP患儿视网膜病变的发展,挽救患儿视功能.临床上需要加强观察和随访,早发现、早诊断、早治疗是减低该病致盲率的惟一方法. 相似文献
43.
单甲氧聚乙二醇化学修饰药物酶的研究进展 总被引:4,自引:0,他引:4
用单甲氧基聚乙二醉(1)化学修饰药物酶是生化药物研究开发的重要手段之一。本文综述了1化学修饰药物酶的一般方法及修饰后酶在生物和理化性质方面的变化,同时对1研究前景进行展望,并指出了尚待解决的问题。 相似文献
44.
45.
46.
The effect of (+/-)-, (+)- and (-)-gossypol on testicular lactate dehydrogenase-X (LDH-X) was studied in vitro and in vivo. It was found that racemic gossypol and the two optical enantiomers had similar inhibitory effects on rat testicular LDH-X in vitro. However, neither racemic gossypol nor the enantiomers exhibited an inhibitory effect on testicular LDH-X in vivo. It is concluded that inhibition of testicular LDH-X is not likely to be the mechanism of the antifertility action of gossypol. The inhibition of testicular LDH-X in vitro by all three preparations of gossypol is probably non-specific. 相似文献
47.
48.
49.
William W. Hurd MD Lei Wang BSc Mark T. Schemmel MD 《American journal of obstetrics and gynecology》1995,173(6):1731-1733
OBJECTIVE: Our purpose was to compare the relative risk of vessel injury after use of a 5 mm conical-tipped trocar, a 5 mm pyramidal-tipped trocar, and a 10 mm pyramidal-tipped trocar in a rabbit vessel model.STUDY DESIGN: Plastic templates were placed in front of and behind 108 mesenteric vessels in 11 anesthetized New Zealand White rabbits. Laparoscopic trocars were inserted through the templates and mesentery. The incidence of vessel injury was determined at distances from the vessels ranging from 0 to 5 mm.RESULTS: The 5 mm conical trocar resulted in a vessel injury rate of 88% at 0 mm from the vessel but 0% at 1 or 2 mm. The 5 mm pyramidal trocar resulted in 100%, 88%, and 62% injury rates of 0, 1, and 2 mm from the vessels, respectively. The 10 mm pyramidal trocar resulted in a 100% injury rate at 0, 1, 2, or 3 mm from the vessels and 80% and 40% at 4 mm and 5mm, respectively.CONCLUSION: The relative risk of vessel injury is significantly increased by the use of pyramidal-tipped trocars when compared with conical-tipped trocars, especially if larger diameter trocars are used. 相似文献
50.
H-D. SHEN S-F. LIAW W-L. LIN L-H. RO† H-L. YANG† S-H. HAN ‡ 《Clinical and experimental allergy》1995,25(4):350-356
To characterize the 68 kDa allergen of Penicillium notatum (also known as P. chrysogenum), a molecular antibody (MoAb) (P40) was previously generated. For cDNA cloning, three more MoAbs (3F, 5A3, 5G2) were generated in the present study. A mixture of all the four MoAbs was used in cloning of the gene coding for the 68 kDa allergen from a λgt11 cDNA library of P. chrysogenum. A cDNA clone (A6) with DNA insert of about 0.5 kb which encodes for the 3′-terminal nucleotide sequence of the 68 kDa allergen was obtained. The cloned sequence contained two putative N-glycosylation sites. The reduction in molecular weight from 68 to 62 kDa in immunoblotting after treatment of the crude extract of P. notatum with N-glycosidase F indicates that the 68 kDa allergen is a glycoprotein. Nucleotide sequence determination showed that 188 (54%) of the 348 nucleotides of the cDNA sequence obtained were identical to the same region of the nucleotide sequence of the beta-N-acetylglucosaminidase gene of Candida albicans. Although the cDNA clone obtained did not encode the full-length gene of the 68 kDa allergen, polypeptide expressed from the A6 cDNA showed positive immunological reactivities to all four MoAbs used in the cloning experiment and to IgE antibodies in sera of asthmatic patients. There was a loss of immunoblotting activity to the 68 kDa component after absorption of MoAb P40-containing culture supernatant with filters blotted on plaque lawns of cDNA clone A6. Moreover, the immunoblotting activity remained when the MoAbs affinity-purified with filters containing polypeptides encoded by the cDNA insert of clone A6 were used. These two observations indicate that clone A6, which encodes 117 amino acid residues of a putative 560-residue polypeptide, is a cDNA clone of the 68 kDa component of P. notatum. In conclusion, results obtained from cloning and characterization of a partial cDNA clone described in this study suggest that the 68 kDa allergen of P. notatum is a beta-N-acetylglucosaminidase. 相似文献