全文获取类型
收费全文 | 1341篇 |
免费 | 110篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 74篇 |
妇产科学 | 20篇 |
基础医学 | 165篇 |
口腔科学 | 32篇 |
临床医学 | 162篇 |
内科学 | 302篇 |
皮肤病学 | 4篇 |
神经病学 | 86篇 |
特种医学 | 182篇 |
外科学 | 208篇 |
综合类 | 44篇 |
预防医学 | 34篇 |
眼科学 | 14篇 |
药学 | 40篇 |
1篇 | |
肿瘤学 | 95篇 |
出版年
2019年 | 9篇 |
2018年 | 15篇 |
2016年 | 10篇 |
2015年 | 11篇 |
2014年 | 21篇 |
2013年 | 19篇 |
2012年 | 29篇 |
2011年 | 36篇 |
2010年 | 23篇 |
2009年 | 24篇 |
2008年 | 41篇 |
2007年 | 56篇 |
2006年 | 49篇 |
2005年 | 46篇 |
2004年 | 52篇 |
2003年 | 46篇 |
2002年 | 37篇 |
2001年 | 47篇 |
2000年 | 42篇 |
1999年 | 38篇 |
1998年 | 34篇 |
1997年 | 33篇 |
1996年 | 33篇 |
1995年 | 34篇 |
1994年 | 32篇 |
1993年 | 45篇 |
1992年 | 37篇 |
1991年 | 23篇 |
1990年 | 31篇 |
1989年 | 43篇 |
1988年 | 39篇 |
1987年 | 51篇 |
1986年 | 39篇 |
1985年 | 37篇 |
1984年 | 19篇 |
1983年 | 26篇 |
1982年 | 21篇 |
1981年 | 33篇 |
1980年 | 19篇 |
1979年 | 15篇 |
1978年 | 18篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1975年 | 14篇 |
1974年 | 13篇 |
1973年 | 12篇 |
1971年 | 8篇 |
1970年 | 8篇 |
1969年 | 8篇 |
1968年 | 17篇 |
排序方式: 共有1465条查询结果,搜索用时 0 毫秒
21.
Sexual behavior of captive lowland gorillas 总被引:1,自引:0,他引:1
Ronald D. Nadler Ph.D. 《Archives of sexual behavior》1976,5(5):487-502
22.
Impact of education for physicians on patient outcomes 总被引:4,自引:0,他引:4
NM Clark M Gong MA Schork D Evans D Roloff M Hurwitz L Maiman RB Mellins 《Pediatrics》1998,101(5):831-836
23.
Hemoglobin and albumin adducts of benzene oxide among workers exposed to high levels of benzene 总被引:3,自引:0,他引:3
Yeowell-O'Connell K; Rothman N; Smith MT; Hayes RB; Li G; Waidyanatha S; Dosemeci M; Zhang L; Yin S; Titenko-Holland N; Rappaport SM 《Carcinogenesis》1998,19(9):1565-1571
Benzene oxide (BO) reacts with cysteinyl residues in hemoglobin (Hb) and
albumin (Alb) to form protein adducts (BO-Hb and BO-Alb), which are
presumed to be specific biomarkers of exposure to benzene. We analyzed
BO-Hb in 43 exposed workers and 42 unexposed controls, and BO-Alb in a
subsample consisting of 19 workers and 19 controls from Shanghai, China, as
part of a larger cross-sectional study of benzene biomarkers. The adducts
were analyzed by gas chromatography-mass spectrometry following reaction of
the protein with trifluoroacetic anhydride and methanesulfonic acid. When
subjects were divided into controls (n = 42) and workers exposed to < or
=31 (n = 21) and >31 p.p.m. (n = 22) benzene, median BO-Hb levels were
32.0, 46.7 and 129 pmol/g globin, respectively (correlation with exposure:
Spearman r = 0.67, P < 0.0001). To our knowledge, these results
represent the first observation in humans that BO-Hb levels are
significantly correlated with benzene exposure. Median BO-Alb levels in
these 3 groups were 103 (n = 19), 351 (n = 7) and 2010 (n = 12) pmol/g Alb,
respectively, also reflecting a significant correlation with exposure
(Spearman r = 0.90, P < 0.0001). The blood dose of BO predicted from
both Hb and Alb adducts was very similar. These results clearly affirm the
use of both Hb and Alb adducts of BO as biomarkers of exposure to high
levels of benzene. As part of our investigation of the background levels of
BO-Hb and BO-Alb found in unexposed persons, we analyzed recombinant human
Hb and Alb for BO adducts. Significant levels of both BO-Hb (19.7 pmol/g)
and BO-Alb (41.9 pmol/g) were detected, suggesting that portions of the
observed background adducts reflect an artifact of the assay, while other
portions are indicative of either unknown exposures or endogenous
production of adducts.
相似文献
24.
Increased aneusomy and long arm deletion of chromosomes 5 and 7 in the lymphocytes of Chinese workers exposed to benzene 总被引:4,自引:1,他引:4
Zhang L; Rothman N; Wang Y; Hayes RB; Li G; Dosemeci M; Yin S; Kolachana P; Titenko-Holland N; Smith MT 《Carcinogenesis》1998,19(11):1955-1961
Two of the most common cytogenetic changes in therapy- and chemical-
related leukemia are the loss and long (q) arm deletion of chromosomes 5
and 7. The detection of these aberrations in lymphocytes of individuals
exposed to potential leukemogens may serve as useful biomarkers of
increased leukemia risk. We have used a novel fluorescence in situ
hybridization (FISH) procedure to determine if specific aberrations in
chromosomes 1, 5 and 7 occur at an elevated rate in the blood cells of
workers exposed to benzene. Forty-three healthy workers exposed to a wide
range of benzene concentrations (median 31 p.p.m., 8 h time-weighted
average) and 44 unexposed controls from Shanghai were studied. Whole blood
was cultured and metaphase spreads were harvested at 72 h. Benzene exposure
was associated with increases in the rates of monosomy 5 and 7 but not
monosomy 1 (P < 0.001, P < 0.0001 and P = 0.94, respectively) and
with increases in trisomy and tetrasomy frequencies of all three
chromosomes. Long arm deletion of chromosomes 5 and 7 was increased in a
dose-dependent fashion (P = 0.014 and P < 0.0001) up to 3.5-fold in the
exposed workers. These results demonstrate that leukemia-specific changes
in chromosomes 5 and 7 can be detected by FISH in the peripheral blood of
otherwise healthy benzene-exposed workers. We suggest that aberrations in
chromosomes 5 and 7 may be useful biomarkers of early biological effect for
benzene exposure.
相似文献
25.
Recombinant human interleukin-11 prevents mucosal atrophy and bowel shortening in the defunctionalized intestine 总被引:6,自引:0,他引:6
Dickinson EC Tuncer R Nadler EP Koltuksuz U Boyle P Alber SM Watkins SC Ford HR 《Journal of pediatric surgery》2000,35(7):1079-1083
BACKGROUND: Mucosal atrophy and bowel shortening are the hallmark of proximal intestinal diversion for extensive necrotizing enterocolitis (NEC) or Thiry-Vella fistulas (TVF), in which the ends of a defunctionalized loop of intestine are exteriorized as stomas. Recombinant human interleukin-11 (rhIL-11) is a pleiotropic cytokine that promotes epithelial regeneration and enhances adaptation after bowel resection. The authors hypothesized that rhIL-11 may prevent mucosal atrophy and bowel shortening in rats with TVF METHODS: After creation of ileal TVF, Sprague-Dawley rats were selected randomly to receive either rhIL-11 or equal volume of 0.1% bovine serum albumin (BSA) subcutaneously daily. On day 14, the TVF were excised and examined morphologically. Enterocyte apoptosis was measured using the TUNEL assay. Mucosal DNA and protein content were measured. RESULTS: Administration of rhIL-11 resulted in a significantly greater weight gain and less shortening of TVF than BSA treatment. TVF from the rhIL-11-treated group showed evidence of hyperplasia and hypertrophy and increased crypt to villus ratio. The BSA group had substantial mucosal atrophy. There was a qualitative decrease in the incidence of apoptosis in the rhIL-11 group. CONCLUSIONS: Recombinant human IL-11 prevents mucosal atrophy and shortening of defunctionalized intestinal loops. It may help reduce the incidence of short gut syndrome in infants with extensive NEC. 相似文献
26.
新生儿复苏培训项目十年回顾 总被引:5,自引:1,他引:5
每年约2000万新生儿出生的中国,鼓励一对夫妻只生一个孩子,随着国民经济迅速发展,生活水平不断提高,每一个新生儿的健康都受到家庭及社会的高度关注。1991年中国要儿死亡率为50.2‰,1998年降至33.3‰,地区性差别很大,贫困地区最高可达56‰,一些条件较好的城市低至7.5‰。围产医学界公认围产窒息为要儿患病及死亡的首要原因,如合并早产、严重肺、脑疾病等后果更为严重。 相似文献
27.
28.
Antigen-specific T-cell memory is preserved in children treated for acute lymphoblastic leukemia 下载免费PDF全文
Haining WN Neuberg DS Keczkemethy HL Evans JW Rivoli S Gelman R Rosenblatt HM Shearer WT Guenaga J Douek DC Silverman LB Sallan SE Guinan EC Nadler LM 《Blood》2005,106(5):1749-1754
Despite profound T-cell immunodeficiency, most patients treated with chemotherapy do not succumb to infection. The basis for residual protective immunity in lymphopenic patients is not known. We prospectively measured T-cell numbers, thymopoiesis, and T-cell memory in 73 children undergoing a 2-year chemotherapy regimen for acute lymphoblastic leukemia (ALL) and compared them to an age-matched cohort of 805 healthy children. Most patients had profound defects in CD4 and CD8 T-cell numbers at diagnosis that did not recover during the 2 years of therapy. Thymic output and the fraction of naive T cells were significantly lower than in healthy controls. However, the remaining T-cell compartment was enriched for antigen-experienced, memory T cells defined both by phenotype and by function. This relative sparing of T-cell memory may, in part, account for the maintenance of protective immunity in lymphopenic patients treated for ALL. Moreover, because the memory T-cell compartment is least affected by ALL and its treatment, strategies to induce immunity to pathogens or tumor antigens in cancer patients may be most successful if they seek to expand pre-existing memory T cells. 相似文献
29.
Interleukin-7 promotes survival and cell cycle progression of T-cell acute lymphoblastic leukemia cells by down-regulating the cyclin-dependent kinase inhibitor p27(kip1) 总被引:8,自引:7,他引:8 下载免费PDF全文
In normal T-cell development interleukin-7 (IL-7) functions as an antiapoptotic factor by regulating bcl-2 expression in immature thymocytes and mature T cells. Similar to what occurs in normal immature thymocytes, prevention of spontaneous apoptosis by IL-7 in precursor T-cell acute lymphoblastic leukemia (T-ALL) cells correlates with up-regulation of bcl-2. IL-7 is also implicated in leukemogenesis because IL-7 transgenic mice develop lymphoid malignancies, suggesting that IL-7 may regulate the generation and expansion of malignant cells. This study shows that in the presence of IL-7, T-ALL cells not only up-regulated bcl-2 expression and escaped apoptosis but also progressed in the cell cycle, resulting in sequential induction of cyclin D2 and cyclin A. Down-regulation of p27kip1 was mandatory for IL-7-mediated cell cycle progression and temporally coincided with activation of cyclin-dependent kinase (cdk)4 and cdk2 and hyperphosphorylation of Rb. Strikingly, forced expression of p27kip1 in T-ALL cells not only prevented cell cycle progression but also reversed IL-7-mediated up-regulation of bcl-2 and promotion of viability. These results show for the first time that a causative link between IL-7-mediated proliferation and p27kip1 down-regulation exists in malignant T cells. Moreover, these results suggest that p27kip1 may function as a tumor suppressor gene not only because it is a negative regulator of cell cycle progression but also because it is associated with induction of apoptosis of primary malignant cells. 相似文献
30.
Percutaneous drainage of chest abscesses in children 总被引:1,自引:0,他引:1
Seven patients ranging in age from 3 to 18 years underwent percutaneous drainage of eight intrathoracic abscesses. Five of the abscesses were mediastinal or paramediastinal and resulted from esophageal perforation or esophageal anastomotic leakage. The abscesses resolved in each case, with a mean catheter drainage time of 28 days and no need for surgical intervention. Three of the abscesses were intrapulmonary, and each lay adjacent to a pleural surface. All three lung abscesses resolved within 19-24 days, without thoracotomy or wedge resection. 相似文献