全文获取类型
收费全文 | 5978篇 |
免费 | 426篇 |
国内免费 | 171篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 199篇 |
妇产科学 | 311篇 |
基础医学 | 753篇 |
口腔科学 | 180篇 |
临床医学 | 757篇 |
内科学 | 1184篇 |
皮肤病学 | 114篇 |
神经病学 | 368篇 |
特种医学 | 152篇 |
外科学 | 797篇 |
综合类 | 213篇 |
一般理论 | 2篇 |
预防医学 | 269篇 |
眼科学 | 197篇 |
药学 | 563篇 |
中国医学 | 88篇 |
肿瘤学 | 371篇 |
出版年
2023年 | 48篇 |
2022年 | 65篇 |
2021年 | 150篇 |
2020年 | 86篇 |
2019年 | 146篇 |
2018年 | 187篇 |
2017年 | 118篇 |
2016年 | 134篇 |
2015年 | 189篇 |
2014年 | 203篇 |
2013年 | 301篇 |
2012年 | 476篇 |
2011年 | 436篇 |
2010年 | 233篇 |
2009年 | 225篇 |
2008年 | 358篇 |
2007年 | 398篇 |
2006年 | 331篇 |
2005年 | 308篇 |
2004年 | 255篇 |
2003年 | 218篇 |
2002年 | 181篇 |
2001年 | 179篇 |
2000年 | 209篇 |
1999年 | 129篇 |
1998年 | 46篇 |
1997年 | 61篇 |
1996年 | 46篇 |
1995年 | 23篇 |
1994年 | 27篇 |
1993年 | 28篇 |
1992年 | 123篇 |
1991年 | 83篇 |
1990年 | 84篇 |
1989年 | 66篇 |
1988年 | 69篇 |
1987年 | 48篇 |
1986年 | 41篇 |
1985年 | 43篇 |
1984年 | 32篇 |
1983年 | 18篇 |
1982年 | 20篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 17篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1973年 | 9篇 |
1971年 | 12篇 |
1970年 | 12篇 |
排序方式: 共有6575条查询结果,搜索用时 15 毫秒
1.
While balloon valvuloplasty has been widely used for the treatment of congenital valvular pulmonary stenosis (PS) in children and adults, its use in elderly patients is less common. An 80-year-old woman with congenital valvular PS received valvuloplasty with double-balloon technique. Right ventricle systolic pressure and pulmonary valve systolic pressure gradient decreased from 95 to 44 mm Hg and from 75 to 35 mm Hg, respectively. Follow-up Doppler echocardiography 2 months later showed further decrease in the transvalvular systolic pressure gradient to 29 mm Hg. The patient had symptomatic relief, and no major complication was noted. Balloon pulmonary valvuloplasty can be an effective treatment for elderly patients with congenital valvular PS. 相似文献
2.
3.
4.
BACKGROUND AND PURPOSE: Taiwan's National Health Insurance (NHI) program has considered the use of capitation payments to health care providers as a method for control of the rising costs of the system. The establishment of capitation payments usually requires the performance of risk adjustment. The purposes of this study were to develop a diagnosis-based risk adjustment model for the NHI and to evaluate its predictability. METHODS: Using a 2% random sample of 371,620 NHI enrollees, the authors developed a Taiwan version of the Principal Inpatient Diagnosis Cost Groups (TPIPDCGs) from 1996 claim records to predict an individual's expenditure in 1997. Weighted least squares regression models were built in an estimation sample (two-thirds of the study sample), and were cross-validated in a validation sample (the remaining one-third of the study sample). Predictive R2 and predictive ratios were used to evaluate the model's predictability. RESULTS: Only 7.88% of the study sample could be classified into 1 of the 16 TPIPDCGs. Combined with demographic variables, which alone could explain 3.7% of the variation in an individual's future expenditure, the risk adjustment model based on TPIPDCGs could explain 12.2% of expenditure variation. In addition, the finding that the predictive ratios of the TPIPDCG model approximated unity better than those of the demographic model in all subgroups indicates that the capitation payment as predicted by the TPIPDCG model for each subgroup would better correlate to the actual spending. CONCLUSION: Taiwan's risk-adjusted capitation model based on principal inpatient diagnoses has higher predictability on individual's future expenditure than its counterpart in the USA. This finding provides insight into not only the development of Taiwan's diagnosis-based risk adjustment models but also the necessity of modification when applying foreign-developed risk adjustment models to the NHI. 相似文献
5.
赛赓啶对 KBV200细胞多药抗性的逆转作用 总被引:3,自引:0,他引:3
研究赛赓啶对KBV200细胞多药抗性的逆转作用及逆转机制。在KBV200细胞,采用MTT法,测出赛赓啶对长春新碱、阿霉素和鬼臼乙叉甙耐药的逆转系数分别为5.5,2.0和1.9,而对5-氟尿嘧啶、美法仑的细胞毒性作用无明显影响,表明赛赓啶为多药抗性逆转剂。荧光分光光度法测定表明,赛赓啶可使KBV200细胞内阿霉素蓄积量增加。流式细胞荧光测定显示赛赓啶可增加罗丹明123的蓄积并减慢其外排。免疫细胞化学及狭缝杂交表明赛赓啶不影响KBV200细胞的P-糖蛋白染色深度和 mdr1 RNA 表达水平。以上结果提示赛赓啶的多药抗性逆转机制是抑制P-糖蛋白泵的功能。 相似文献
6.
Y M Chung T S Yeh Y Y Tsai H Chiang J H Liu 《Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift für Augenheilkunde》1988,196(3):161-166
Lymphomatoid granulomatosis is an angiocentric and angiodestructive lympho-proliferative disorder involving multisystems but rarely conjunctiva. We present a 62-year-old Chinese female with lymphomatoid granulomatosis who had an ulcerative conjunctival nodule. Conjunctival biopsy revealed pathological findings important for diagnosis and indicating progression of disease severity. To our knowledge, this is the first report to demonstrate pathological findings characteristic of lymphomatoid granulomatosis with conjunctival involvement. 相似文献
7.
8.
Urethral reconstruction with graft substances, such as skin and bladder mucosa, has been previously used when primary anastomosis cannot be achieved. However, stricture and meatal prolapse are associated with these grafts. We report the use of buccal mucosa for the reconstruction of urethral defects in 3 patients. One patient with failed operation for hypospadias received tube buccal mucosal graft for urethral replacement. Two patients with urethral necrosis and stricture received onlay buccal mucosal graft. All patients were disease-free during follow-up (range, 12 to 49 months; mean, 36 months). One patient had a pinhole fistula that was successfully managed with simple repair. This technique appears to be useful for urethral reconstruction when a local graft is not available, even in patients with complicated conditions. 相似文献
9.
C L Yu C Y Tsai S Y Hong C S Lue C C Chiu B N Chiang S H Han S R Wang 《Scandinavian journal of rheumatology》1991,20(1):8-15
Extracellular phospholipase A2 (PLA2) is a proinflammatory enzyme found especially in the inflammatory exudate to modulate blood flow to areas of antigen stimulation. In this study we found that PLA2 exerted a biphasic effect on the proliferation of phytohemagglutinin (PHA)-stimulated human mononuclear cells (PHA MNC). At low concentrations range from 0.001 to 1 U/ml, PLA2 enhanced the proliferation of PHA MNC (maximal increase was 37.0 +/- 5.67%). Conversely, at concentrations over 10 U/ml, PLA2 markedly suppressed the PHA-induced MNC proliferation (maximal decrease was 88.86 +/- 2.89%). PLA2 was non-toxic to lymphocytes after three days culture, unless the concentration was higher than 100 U/ml. The membrane polarization of PHA-stimulated lymphocytes was also increased by PLA2 at a low concentration. In addition, PLA2 displayed a similar effect on the proliferation of streptokinase-streptodornase (SK/SD) or allogeneic cell stimulated lymphocytes. The change of lymphocyte proliferation by PLA2, was parallel to the change of percentage of helper T cells. Furthermore--a CD4-rich population was proved more susceptible to PLA2 effect than a CD8-rich population. Para-bromophenacyl bromide (pBPB), an irreversible inhibitor of PLA2, abrogated the biphasic effect of PLA2 on PHA MNC proliferation. These results suggest that PLA2 plays a regulatory role on immune reactions by modulating the percentage of helper T cells. 相似文献
10.
Immunomodulators from Paris formosana Hayata. 总被引:1,自引:0,他引:1
Eight glycosides PF-1 to PF-8 were isolated from the leaves and stems of Paris formosana Hayata (Liliaceae), of which PF-3 (III) was the main compound. It was found that PF-1 to PF-3 (I-III) caused proliferative responses of mouse lymphocytes to concanavalin A and augmentation of mouse granulocyte/macrophage colony forming cells in mouse fibroblast cell L929 conditioned medium. PF-4(IV) and PF-8 showed significant immunomodulatory effects with very low toxicity: they not only caused the same immune responses as PF-1, 2 & 3 but also enhanced the proliferative response of human peripheral whole blood to phytohemagglutinin. PF-5 (V) also increased 3H-thymidine incorporation in ConA-stimulated lymphocytes and in PHA-stimulated human peripheral whole blood, and enhanced the proliferative response of granulocyte/macrophage colony stimulating activity. PF-6(VI) and PF-7(VII) augmented 3H-thymidine incorporation in granulocyte/macrophage colony-forming cells and mitogenic response of PHA-stimulated human peripheral whole blood cells from healthy adults. However, PF-1, 2 and 3 showed hemolytic action, while PF-4 to PF-8 had no hemolytic action at all. On the other hand, the hemolytic action of PF-3 derivatives was reduced as compared with PF-3 but their immune responses did not equal those of PF-3, only showing granulocyte/macrophage colony stimulating activity. 相似文献