全文获取类型
收费全文 | 1323篇 |
免费 | 61篇 |
国内免费 | 113篇 |
专业分类
儿科学 | 63篇 |
妇产科学 | 10篇 |
基础医学 | 140篇 |
口腔科学 | 22篇 |
临床医学 | 161篇 |
内科学 | 345篇 |
皮肤病学 | 39篇 |
神经病学 | 32篇 |
特种医学 | 362篇 |
外国民族医学 | 1篇 |
外科学 | 69篇 |
综合类 | 40篇 |
预防医学 | 64篇 |
眼科学 | 12篇 |
药学 | 77篇 |
中国医学 | 1篇 |
肿瘤学 | 59篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 14篇 |
2017年 | 2篇 |
2016年 | 19篇 |
2015年 | 19篇 |
2014年 | 18篇 |
2013年 | 38篇 |
2012年 | 14篇 |
2011年 | 33篇 |
2010年 | 47篇 |
2009年 | 50篇 |
2008年 | 30篇 |
2007年 | 73篇 |
2006年 | 30篇 |
2005年 | 55篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 15篇 |
2001年 | 16篇 |
2000年 | 21篇 |
1999年 | 19篇 |
1998年 | 93篇 |
1997年 | 95篇 |
1996年 | 103篇 |
1995年 | 63篇 |
1994年 | 61篇 |
1993年 | 64篇 |
1992年 | 9篇 |
1991年 | 27篇 |
1990年 | 23篇 |
1989年 | 46篇 |
1988年 | 36篇 |
1987年 | 48篇 |
1986年 | 27篇 |
1985年 | 44篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 25篇 |
1981年 | 20篇 |
1980年 | 30篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1977年 | 16篇 |
1976年 | 26篇 |
1975年 | 15篇 |
1970年 | 2篇 |
排序方式: 共有1497条查询结果,搜索用时 15 毫秒
41.
Background
Local measurements of health behaviors, diseases, and use of health services are critical inputs into local, state, and national decision-making. Small area measurement methods can deliver more precise and accurate local-level information than direct estimates from surveys or administrative records, where sample sizes are often too small to yield acceptable standard errors. However, small area measurement requires careful validation using approaches other than conventional statistical methods such as in-sample or cross-validation methods because they do not solve the problem of validating estimates in data-sparse domains. 相似文献42.
43.
黄河流域11个地区51个干休所离退休干部认知障碍及老年痴呆危险因素分析 总被引:4,自引:0,他引:4
目的:调查兰州部队辖区黄河流域老年痴呆及认知障碍的患病率并分析其危险因素。方法:应用《长谷川智力量表》(22~30.5分为轻度异常,10.5~21.5分为痴呆前期,≤10分为痴呆期)和《临床记忆量表》(≤80分为异常),对黄河流域11个地区51个干休所16538人群中2944名60岁以上人员进行调查。采用挨家挨户一对一的的方法开展调查检测,只有2个量表评分均为异常才列为病例组,同时对一般情况、驻地海拔高度、家族遗传史、既往病史、生活习惯等5个方面30个危险因素进行调查,并应用SPSS10.0软件包将调查结果进行多元回归分析。结果:2944名受试者全部完成测试进入结果分析。①老年痴呆的患病率分别为痴呆0.71%,痴呆前期2.11%,轻度异常28.46%,总患病率为31.28%。②多元回归分析结果:脑萎缩(t=-6.304)、重大生活事件(t=-5.328)、高龄(t=-5.415)、无喝茶嗜好(t=-3.802)、脑梗死(t=-3.343)、女性(t=-2.604)、冠心病(t=2.496)、低文化程度(t=1.973)、职业(t=1.965)、高海拔地区(t=1.957)与老年痴呆相关(P均<0.05)。结论:①黄河流域老年痴呆及认知障碍发生与脑萎缩、重大生活事件、高龄、无喝茶嗜好、脑梗死、女性、冠心病、低文化程度、职业、高海拔地区等10种危险因素有关。②结果显示痴呆发病率较低,而痴呆前期及轻度异常发病率较高,所以应重视痴呆前期及轻度异常患者的干预治疗。 相似文献
44.
The effectiveness of bone marrow transplantation (BMT) for malignant blood diseases remains limited by the inability of the preparative regimen to eliminate the disease without causing toxicity to normal organs. We have used 52Fe to deliver radiotherapy selectively to the BM. Fourteen patients with hematologic malignancies received 52Fe before a conventional BMT conditioning regimen. The median 52Fe dose was 58 mCi (range, 32 to 85 mCi). As evaluated by quantitative scanning, the median percentage of 52Fe taken up by the BM was 82% (range, 36% to 90%). This resulted in a median radiation-absorbed dose to the BM of 632 rad (range, 151 to 1,144 rad). The median uptake of 52Fe by the liver was 18% (range, 10% to 64%) and the median radiation- absorbed dose to the liver was 239 rad (range, 82 to 526 rad). The median whole body radiation-absorbed dose was 46 rad (range, 22 to 68 rad). No untoward effects were noted after the injections of 52Fe. The patients recovered hematopoiesis without toxicity in excess of that expected with conventional conditioning alone. The median follow-up was 8 months and three patients have relapsed. 52Fe should provide a way to boost the radiation dose to marrow-based diseases before marrow transplantation without increasing toxicity. 相似文献
45.
p16 gene homozygous deletions in acute lymphoblastic leukemia 总被引:15,自引:4,他引:15
Quesnel B; Preudhomme C; Philippe N; Vanrumbeke M; Dervite I; Lai JL; Bauters F; Wattel E; Fenaux P 《Blood》1995,85(3):657-663
The p16 protein is a cyclin inhibitor encoded by a gene located in 9p21, which may have antioncogenic properties, and is inactivated by homozygous p16 gene deletion or, less often, point mutation in several types of solid tumors often associated to cytogenetic evidence of 9p21 deletion. We looked for homozygous deletion and point mutation of the p16 gene in acute lymphoblastic leukemia (ALL), where 9p21 deletion or rearrangement are also nonrandom cytogenetic findings. Other hematologic malignancies including acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), chronic lymphocytic leukemia (CLL), and myeloma were also studied. Homozygous deletion of the p16 gene was seen in 9 of the 63 (14%) ALL analyzed, including 6/39 precursor B-ALL, 3/12 T-ALL, and 0/12 Burkitt's ALL. Three of the 7 ALL with 9p rearrangement (including 3 of the 5 patients where this rearrangement was clearly associated to 9p21 monosomy) had homozygous deletion compared to 5 of the 55 patients with normal 9p (the last patient with homozygous deletion was not successfully karyotyped). Single stranded conformation polymorphism analysis of exons 1 and 2 of the p16 gene was performed in 88 cases of ALL, including the 63 patients analyzed by Southern blot. Twenty-six of the cases had 9p rearrangement, associated to 9p21 monosomy in at least 12 cases. A missense point mutation, at codon 49 (nucleotide 164), was seen in only 1 of the 88 patients. No homozygous deletion and no point mutation of the p16 gene was seen in AML, MDS, CLL, and myeloma. Homozygous deletion of interferon alpha genes (situated close to p16 gene in 9p21) was seen in only 3 of the 9 ALL patients with p16 gene homozygous deletion, and none of the ALL without p16 gene homozygous deletion. Our findings suggest that homozygous deletion of the p16 gene is seen in about 15% of ALL cases, is not restricted to cases with cytogenetically detectable 9p deletion, and could have a pathogenetic role in this malignancy. On the other hand, p16 point mutations are very rare in ALL, and we found no p16 homozygous deletions or mutations in the other hematologic malignancies studied. 相似文献
46.
We have demonstrated that 0.2% to 11% of cells from the fetal liver (FL) reacted specifically with high concentrations of anti-CD4 monoclonal antibody (MoAb). CD4+ cells from FL were similar in surface phenotype and fluorescence characteristics to the CD4+ population found previously in adult bone marrow (BM). FL and BM cells were seeded in cultures that allow differentiation to primitive precursors. FL cells released many low CD4+ and low Thy+ cells in the supernatant, while BM cells seeded under the same conditions did not. We studied the nonadherent cells harvested from 10-day FL cultures (greater than 90% low CD4+). In methylcellulose, they were able to produce more colonies that appear to be characteristic of earlier stages in the hierarchy of hematopoietic precursors (especially erythroid bursts and colonies composed of both myeloid and erythroid elements) in comparison with CD4- cells from 10-day BM cultures. CD4+ cells harvested from FL cultures initiated secondary cultures containing both a stromal layer and large hematopoietic colonies when replated under conditions similar to those of primary cultures. Furthermore, a limited number of CD4+ cells from 10-day FL cultures were able to repopulate lethally irradiated mice. Although we cannot formally exclude the possibility that the low CD4 cells produced in FL cultures were derived exclusively from the proliferation of the few CD4 cells found in fresh FL, the dynamic analysis of the development of these cells in culture favors the generation of this important population from a CD4- subset of hematopoietic stem cells (HSCs). We speculate that FL contains a prevalent population of very primitive cells not expressing the CD4 antigen, tentatively called "pre-low CD4 precursors." These primitive cells can differentiate into low CD4+ cells that share many characteristics with pluripotent HSCs of the adult type. These data indicate the possibility of using hematopoietic progenitors obtained by the expansion/differentiation of fetal stem cells in culture for transplantation purposes. 相似文献
47.
Interleukin-10 is a proliferation factor but not a differentiation factor for human myeloma cells 总被引:4,自引:3,他引:4
Lu ZY; Zhang XG; Rodriguez C; Wijdenes J; Gu ZJ; Morel-Fournier B; Harousseau JL; Bataille R; Rossi JF; Klein B 《Blood》1995,85(9):2521-2527
Because interleukin-10 (IL-10) is a potent differentiation factor of human B cells into mature plasma cells, we investigated its effect on human malignant plasma cells. IL-10 did not induce any differentiation and increase in Ig synthesis in four human IL-6-dependent malignant plasma cell lines. However, it stimulated the proliferation of two of four cytokine-dependent cell lines in the absence of IL-6 and IL-10- dependent myeloma cell lines have been obtained. The myeloma cell growth activity of IL-10 was unaffected by anti-IL-6 and anti-IL-6R antibodies. Similarly, IL-10 stimulated (P = .001) the proliferation of freshly-explanted myeloma cells in IL-6-deprived cultures of tumor samples from patients with active multiple myeloma (MM) and produced twice as many myeloma cells in these cultures. Again, this cytokine was unable to induce further differentiation (assessed by rate of Ig production) of fresh myeloma cells. A very sensitive enzyme-linked immunosorbent assay (ELISA; 1 pg/mL) only rarely detected IL-10 in the sera of MM patients (3 of 89). On the contrary, serum IL-10 was detected in 60% of patients with plasma cell leukemia (12 of 20). These data show that IL-10 is an IL-6-unrelated growth factor for malignant plasmablastic cells. This cytokine could be involved in the late phase of MM in vivo. 相似文献
48.
49.
JL Boland HAM Corbeij W Van Der Giessen R Seabra-Gomes H Suryapranata W Wijns 《Acute cardiac care》2013,15(4):215-225
AIMS: The BiodivYsio? stent (Biocompatibles Ltd, Farnham, UK) is coated with a phosphorylcholine (PC)-containin copolymer to confer biocompatibility. The SOPHOS (Study Of PHosphorylcholine coating On Stents) study was designed to assess the safety and efficacy of this novel coronary stent and by indirect comparison to indicate equivalence with other formal stent studies. METHODS AND RESULTS: Patients with angina and a single short ( r 12 mm) de novo lesion in a native coronary artery of S 2.75 mm diameter were included. A total of 425 patients were allocated in 24 centers. Clinical data were collected at one-, six- and nine-month follow-up. Angiography was performed before and after the stent implantation. In addition, in the first 200 patients (SOPHOS A) angiography was routinely performed at six months. The following 225 patients (SOPHOS B) were merely followed up clinically. The primary end-point of the study, the six-month MACE-rate (MACE = Major Adverse Cardiac Events) was 13.4% (two cardiac death; five Q-wave/nine non-Qwave myocardial infarctions (MI); nine CABG and 32 target lesion revascularization (TLR), which is similar to the calculated 15% MACE-rate in comparable reference studies. Secondary end-points included among others restenosis at six months in the SOPHOS A population. The target vessel diameter was 2.98 - 0.48 mm. Minimal lumen diameter pre/post procedure and at follow-up was 1.00 - 0.32, 2.69 - 0.37, 1.91 - 0.71mm, respectively. The binary restenosis rate ( S 50% diameter stenosis at follow-up) was 17.7%. CONCLUSION: The coronary BiodivYsio stent is safe and effective as a primary device for the treatment of native coronary artery lesions in patients with stable or unstable angina pectoris. Clinical and angiographic results are in the statistical range of equivalence with comparable studies with other current stents. (Int J Cardiovasc Intervent 2000; 3: 215-225) 相似文献
50.
Acute leukemia associated with the t(4;11) chromosome rearrangement: ultrastructural and immunologic characteristics 总被引:7,自引:1,他引:7
Parkin JL; Arthur DC; Abramson CS; McKenna RW; Kersey JH; Heideman RL; Brunning RD 《Blood》1982,60(6):1321-1331
The acute leukemia associated with the t(4;11) chromosome rearrangement is characterized by relatively consistent clinical features: occurrence primarily in young individuals, hyperleukocytosis, and poor response to therapy. This study describes the morphological, ultrastructural, and immunologic characteristics of the leukemic cells from ten patients with this type of leukemia. The morphological features of the leukemic blasts vary from lymphoid-appearing to monocytic. Ultrastructurally and cytochemically, some of the lymphoid-appearing blasts possess features of myeloid origin. The immunologic phenotype is characteristically E- SIg- CALLA- BA-1- BA-2+ HLA-DR+ and TdT+. These findings suggest that the t(4;11)-associated acute leukemia represents a proliferation of an early myeloid progenitor cell. 相似文献