全文获取类型
收费全文 | 1050篇 |
免费 | 59篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 105篇 |
妇产科学 | 12篇 |
基础医学 | 119篇 |
口腔科学 | 38篇 |
临床医学 | 127篇 |
内科学 | 229篇 |
皮肤病学 | 17篇 |
神经病学 | 45篇 |
特种医学 | 119篇 |
外科学 | 88篇 |
综合类 | 20篇 |
预防医学 | 41篇 |
眼科学 | 6篇 |
药学 | 91篇 |
中国医学 | 1篇 |
肿瘤学 | 84篇 |
出版年
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 17篇 |
2017年 | 8篇 |
2016年 | 14篇 |
2015年 | 21篇 |
2014年 | 39篇 |
2013年 | 48篇 |
2012年 | 34篇 |
2011年 | 35篇 |
2010年 | 37篇 |
2009年 | 51篇 |
2008年 | 33篇 |
2007年 | 57篇 |
2006年 | 45篇 |
2005年 | 35篇 |
2004年 | 22篇 |
2003年 | 25篇 |
2002年 | 33篇 |
2001年 | 22篇 |
2000年 | 24篇 |
1999年 | 34篇 |
1998年 | 37篇 |
1997年 | 42篇 |
1996年 | 38篇 |
1995年 | 27篇 |
1994年 | 36篇 |
1993年 | 22篇 |
1992年 | 18篇 |
1991年 | 19篇 |
1990年 | 19篇 |
1989年 | 24篇 |
1988年 | 24篇 |
1987年 | 20篇 |
1986年 | 17篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 14篇 |
1980年 | 14篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1974年 | 3篇 |
1973年 | 6篇 |
排序方式: 共有1143条查询结果,搜索用时 31 毫秒
1.
2.
3.
Biochemical mechanisms underlying acrylamide induced neurotoxicity were examined using an in vitro model consisting of sagittal slices of rat brain. Incubation of brain slices under oxygen in artificial cerebrospinal fluid containing acrylamide produced a dose and time dependent inhibition of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Lysosomal enzymes, acid phosphatase, N-acetyl glucosaminidase and beta-glucuronidase decreased in a similar manner, while no changes were observed in the activity of Na+K+ATPase, cytochrome c oxidase and lactate dehydrogenase. Incubation of slices with two structurally related compounds, acetamide (a non-neurotoxic amide) and methylene bis-acrylamide (a weak neurotoxin), indicated that acrylamide selectively inhibited GAPDH, enolase and N-acetyl glucosaminidase at low concentration; similar doses of acetamide and methylene bis-acrylamide did not have the same effect on brain slices. Incubation with acrylamide depleted glutathione levels in slices, and the addition of glutathione to the incubation medium prevented acrylamide induced inhibition of GAPDH and lysosomal enzymes. Time dependent inhibition of lysosomal enzymes was also observed in vivo, in the brain and sciatic nerve of rats following a single dose of acrylamide. These results demonstrate that both in vitro and in vivo, lysosomal enzymes are also inhibited following acrylamide exposure. The rat brain slice model exhibits both selectivity and sensitivity towards neurotoxicants and hence, may prove to be an useful in vitro model for the mechanistic evaluation of neurotoxicity. 相似文献
4.
The ganglioside composition of human melanoma was analyzed in five sets of tumor specimens obtained directly from surgery, from the autologous tissue culture cell lines, and from the autologous cell lines grown in athymic nude mice. Total gangliosides of these 15 melanoma specimens were isolated and purified, and the amount of each component ganglioside was analyzed by thin-layer chromatography and a thin-layer chromatography scanner. The ganglioside composition of the five surgical melanoma specimens clearly exhibited different patterns from each other. Moreover, none of the autologous cultured melanomas possessed the same ganglioside composition as their original biopsied tumors. However, when these melanoma cell lines were transplanted into nude mice, the ganglioside composition was converted back to the same ganglioside pattern as in the original surgical specimens. The results support the view that changes in the ganglioside composition of melanoma during in vitro growth are caused by the culture environment rather than by selection of melanoma cells with a particular genotype. Reestablishment of the original ganglioside patterns after passage in nude mice provides clear evidence that in vivo expression of gangliosides is a conserved and stable function specified by the human melanoma cells. 相似文献
5.
6.
7.
We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder. 相似文献
8.
Hausegger KA; Cragg AH; Lammer J; Lafer M; Fluckiger F; Klein GE; Sternthal MH; Pilger E 《Radiology》1994,190(1):199
9.
Rosenberg ZS; Jahss MH; Noto AM; Shereff MJ; Cheung Y; Frey CC; Norman A 《Radiology》1988,167(2):489-493
Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture. 相似文献
10.