全文获取类型
收费全文 | 386篇 |
免费 | 25篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 11篇 |
妇产科学 | 2篇 |
基础医学 | 46篇 |
口腔科学 | 5篇 |
临床医学 | 41篇 |
内科学 | 132篇 |
皮肤病学 | 2篇 |
神经病学 | 16篇 |
特种医学 | 90篇 |
外科学 | 37篇 |
综合类 | 14篇 |
预防医学 | 4篇 |
眼科学 | 6篇 |
药学 | 22篇 |
肿瘤学 | 9篇 |
出版年
2022年 | 6篇 |
2021年 | 4篇 |
2019年 | 5篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 5篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 6篇 |
2007年 | 9篇 |
2006年 | 27篇 |
2005年 | 13篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 14篇 |
1997年 | 5篇 |
1996年 | 19篇 |
1995年 | 15篇 |
1994年 | 16篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 10篇 |
1989年 | 16篇 |
1988年 | 16篇 |
1987年 | 14篇 |
1986年 | 12篇 |
1985年 | 17篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1967年 | 4篇 |
1962年 | 3篇 |
1928年 | 2篇 |
1927年 | 3篇 |
1926年 | 2篇 |
排序方式: 共有438条查询结果,搜索用时 0 毫秒
91.
Certain fetal cranial abnormalities found on second-trimester sonograms can be signs of an open spina bifida. In particular, an abnormal configuration of the cerebellum, known as the banana sign, has been associated with neural tube defects. To further evaluate the usefulness of this sign, the authors compared images of the posterior fossa in 23 fetuses who had documented neural tube defects with those of 38 control fetuses who underwent sonography because of an elevated maternal serum alpha-fetoprotein level. Twenty-two of the 23 fetuses with neural tube defects had compression and anterior alignment of the cerebellar hemispheres (the banana sign), and follow-up confirmed the presence of an open neural tube defect. One fetus had a normal-appearing posterior fossa; however, the neural tube defect at birth was completely covered with skin. Four of the neural tube defects were difficult to see sonographically, and the abnormal configuration of the cerebellum, as well as the flattening of the frontal bone (lemon sign), was instrumental in suggesting the correct diagnosis. The 38 control fetuses had normal-appearing posterior fossae. 相似文献
92.
Selection of platelets for refractory patients by HLA matching and prospective crossmatching 总被引:2,自引:0,他引:2
G Moroff ; G Garratty ; JM Heal ; BR MacPherson ; D Stroncek ; ST Huang ; W Ho ; LD Petz ; MF Leach ; SS Lennon ; et al. 《Transfusion》1992,32(7):633-640
A multi-site clinical study compared platelets chosen for refractory patients by prospective platelet crossmatching using stored donor platelets and HLA-based selection. Seventy-three patients who were refractory to random-donor platelets received two plateletpheresis components, one chosen by HLA-based criteria and the other by crossmatching. Patients were carefully evaluated to exclude nonimmune factors that could adversely affect transfusion results. Each of the five study sites used a crossmatch procedure with which it had experience. Results from this study indicate the following: 1) The overall rate of successful transfusion was similar when an HLA-based method of donor selection that includes all grades of matching and mismatching was compared to a crossmatch-based method of donor selection. 2) HLA-based selection that restricts recipients to grade A and BU matches was superior to a selection method based upon crossmatching alone. Donor selection based on HLA matching (grades A or BU) was also superior to selection based on any degree of HLA mismatching (grades BX, C, or D). 3) Selection of donors based on HLA-cross-reactive groups (defined by in vitro serologic crossreactivity) was no more successful than that based on grade C and D mismatches and was no more successful than selection by crossmatching alone. 4) Lymphocytotoxic and platelet antibodies were not detected in many of the enrolled patients, even though patients demonstrating nonimmune factors were eliminated from the study. It can be concluded that HLA-compatible (grades A and BU) platelets provide optimal support for refractory patients, but that crossmatch-selected platelets are acceptable as an alternative component. 相似文献
93.
TheFirstWorldChineseCongresofDigestionwasheldinBeijingfromOctober20to22,1998inthebeautifulcapitalcityofBeijing.Thespecificaim... 相似文献
94.
We tested whether the in vivo infusion of recombinant, soluble CTLA4 fused with Ig heavy chains, as a surrogate ligand used to block CD28/CTLA4 T-cell costimulation, could prevent efficient T-cell activation and thereby reduce graft-versus-host disease (GVHD). Lethally irradiated B10.BR recipients of major histocompatibility complex disparate C57BL/6 donor grafts received intraperitoneal injections of human CTLA4-Ig (hCTLA4-Ig) or murine CTLA4-Ig (mCTLA4-Ig) in various doses and schedules beginning on day -1 or day 0 of bone marrow transplantation (BMT). In all five experiments, recipients of CTLA4-Ig had a significantly higher actuarial survival rate compared to mice injected with an irrelevant antibody control (L6) or saline alone. Survival rates in recipients of hL6 or PBS were 0% at 29 to 45 days post-BMT. In recipients of CTLA4-Ig, survival rates were as high as 63% mice surviving 3 months post-BMT. However, protection was somewhat variable and recipients of CTLA4-Ig were not GVHD-free by body weight, clinical appearance, and histopathologic examination. There were no significant differences in the survival rates in comparing injection dose, injection duration, or species of CTLA4-Ig (hCTLA4-Ig v mCTLA4- Ig). Splenic and peripheral blood flow cytometry studies of long-term hCTLA4-Ig-injected survivors showed a significant peripheral B-cell and CD4+ T-cell lymphopenia, consistent with GVHD. A kinetic study of splenic reconstitution was performed in mice that received hCTLA4-Ig and showed that mature splenic localized CD8+ T-cell repopulation was not significantly different in recipients of hCTLA4-Ig compared with hL6, despite the significant increase in actuarial survival rate in that experiment. These data suggest that the beneficial effect of hCTLA4-Ig on survival is not mediated by interfering with mature donor- derived T-cell repopulation post-BMT. Neither hCTLA4-Ig nor mCTLA4-Ig interfered with hematopoietic recovery post-BMT. We conclude that CTLA4- Ig (most likely in combination with other agents) may represent an important new modality for GVHD prevention. 相似文献
95.
A comparison between activated protein C and des-1-41-light chain- activated protein C in reactions with type 1 plasminogen activator inhibitor 总被引:2,自引:0,他引:2
This study investigates the role of the gamma-carboxyglutamic acid (gla) containing domain of activated protein C in interactions with both platelet-derived and purified type 1 plasminogen activator inhibitor (PAI-1). The activity of human platelet PAI-1 was neutralized to the same extent by bovine activated protein C and bovine des-1-41- light chain-activated protein C. Both forms of activated protein C formed SDS-stable, divalent-cation independent complexes with platelet PAI-1, as demonstrated by immunoblotting using antibodies directed to either protein C or PAI-1. Since activated protein C neutralized PAI-1, the potential inhibition of the enzyme by PAI-1 was studied. Purified PAI-1 inhibited the amidolytic activity of bovine-activated protein C and bovine des-1-41-light chain-activated protein C with a k2 of 2.85 X 10(4) M-1 sec-1 for both proteins. These data suggest that the gla domain of activated protein C is not required for neutralization of PAI- 1 activity, for complex formation with PAI-1, or for inhibition of the amidolytic activity of activated protein C by PAI-1. 相似文献
96.
97.
98.
Jian‐Hui Tian, Ling‐Shuang Liu, Zhi‐Ming Shi and Zhi‐Yi Zhou. A randomized controlled pilot trial of ‘Feiji recipe’ on quality of life on non‐small cell lung cancer patients. Am J Chin Med 2010; 38: 15–25. 相似文献
99.
100.