全文获取类型
收费全文 | 817篇 |
免费 | 98篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 42篇 |
妇产科学 | 9篇 |
基础医学 | 71篇 |
口腔科学 | 21篇 |
临床医学 | 78篇 |
内科学 | 206篇 |
皮肤病学 | 21篇 |
神经病学 | 21篇 |
特种医学 | 129篇 |
外科学 | 64篇 |
综合类 | 44篇 |
预防医学 | 43篇 |
眼科学 | 89篇 |
药学 | 24篇 |
肿瘤学 | 69篇 |
出版年
2021年 | 13篇 |
2020年 | 12篇 |
2019年 | 12篇 |
2018年 | 29篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 25篇 |
2014年 | 15篇 |
2013年 | 33篇 |
2012年 | 21篇 |
2011年 | 38篇 |
2010年 | 19篇 |
2009年 | 44篇 |
2008年 | 33篇 |
2007年 | 43篇 |
2006年 | 36篇 |
2005年 | 34篇 |
2004年 | 25篇 |
2003年 | 23篇 |
2002年 | 26篇 |
2001年 | 19篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 53篇 |
1997年 | 51篇 |
1996年 | 22篇 |
1995年 | 26篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 5篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 10篇 |
1979年 | 6篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 14篇 |
1974年 | 9篇 |
1973年 | 9篇 |
1972年 | 6篇 |
1970年 | 5篇 |
1969年 | 5篇 |
排序方式: 共有932条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors. 相似文献
2.
P. H. Feng F. J. Jayaratnam E. P. C. Tock C. S. Seah 《International journal of rheumatic diseases》2003,6(1):64-67
This paper describes our experience with cyclophosphamide in the treatment of systemic lupus erythematosus. Since 1965, 42 such patients have been treated either singly with cyclophosphamide or in combination with steroid. Serious complications have been rare except for amenorrhoea, which occurred in 14 out of 32 patients within the reproductive period. Our experience suggests that cyclophosphamide has an important, though not primary, part to play in the therapy of this disease. 相似文献
3.
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
4.
Intestinal schistosomiasis japonica: CT-pathologic correlation 总被引:1,自引:0,他引:1
Lee RC; Chiang JH; Chou YH; Rubesin SE; Wu HP; Jeng WC; Hsu CC; Tiu CM; Chang T 《Radiology》1994,193(2):539
5.
Dyskeratosis congenita has been found to be associated with abnormal immune function. In this study we report a patient with this association. He developed Pneumocystis carinii interstitial pneumonia, and impaired cell mediated immunity was confirmed by the presence of depressed lymphoproliferative responses to in vitro stimulation with mitogen. Enumeration of T cell subsets showed a severely depressed CD4:CD8 ratio (0.38), which is the likely cause for impaired cell mediated immunity. The T cell activation pathway appeared intact, as his T lymphocytes were able to express activation markers (CD25 and HLA-DR) after mitogen stimulation. 相似文献
6.
7.
8.
9.
10.
Zhan Y Brown LE Deliyannis G Seah S Wijburg OL Price J Strugnell RA O'Connell PJ Lew AM 《Immunologic research》2004,30(1):1-14
The most common models of CD4 T-cell deficiency are mice exogenously injected with anti-CD4 antibody (Ab), CD4 knockout (CD4−/−) and major histocompatibility complex (MHC) class II knockout (class II−/−) mice. We recently described the anti-CD4 Ab transgenic mouse (GK) as an improved CD4 cell-deficient model. This review compares
this new GK mouse model with the widely available class II−/− and CD4−/− mice, when exposed to complex antigens (foreign grafts and during bacterial or viral infection). We highlight here the cytometric
and functional differences (including Ab isotype, viral or bacterial clearance, and graft survival) among these CD4 cell-deficient
models. For example, whereas grafts are generally rejected in class II−/− and CD4−/− mice as quickly as in wild-type mice, they survive longer in GK mice. Also, CD4−/− mice produce IgG against both simple model and complex antigens, but class II−/− and GK mice produce small amounts of IgG2a against complex antigens but not simple model antigens. These differences harbinger
the caveats in the use of these various mice. 相似文献