全文获取类型
收费全文 | 2237篇 |
免费 | 140篇 |
国内免费 | 115篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 81篇 |
妇产科学 | 30篇 |
基础医学 | 240篇 |
口腔科学 | 45篇 |
临床医学 | 237篇 |
内科学 | 488篇 |
皮肤病学 | 53篇 |
神经病学 | 69篇 |
特种医学 | 421篇 |
外国民族医学 | 1篇 |
外科学 | 194篇 |
综合类 | 53篇 |
一般理论 | 1篇 |
预防医学 | 114篇 |
眼科学 | 13篇 |
药学 | 108篇 |
中国医学 | 1篇 |
肿瘤学 | 338篇 |
出版年
2022年 | 13篇 |
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 21篇 |
2018年 | 28篇 |
2017年 | 12篇 |
2016年 | 26篇 |
2015年 | 27篇 |
2014年 | 29篇 |
2013年 | 55篇 |
2012年 | 44篇 |
2011年 | 85篇 |
2010年 | 69篇 |
2009年 | 65篇 |
2008年 | 67篇 |
2007年 | 105篇 |
2006年 | 74篇 |
2005年 | 83篇 |
2004年 | 49篇 |
2003年 | 50篇 |
2002年 | 55篇 |
2001年 | 46篇 |
2000年 | 77篇 |
1999年 | 49篇 |
1998年 | 109篇 |
1997年 | 106篇 |
1996年 | 118篇 |
1995年 | 69篇 |
1994年 | 72篇 |
1993年 | 76篇 |
1992年 | 37篇 |
1991年 | 51篇 |
1990年 | 45篇 |
1989年 | 71篇 |
1988年 | 61篇 |
1987年 | 65篇 |
1986年 | 48篇 |
1985年 | 60篇 |
1984年 | 38篇 |
1983年 | 28篇 |
1982年 | 31篇 |
1981年 | 27篇 |
1980年 | 35篇 |
1979年 | 18篇 |
1978年 | 18篇 |
1977年 | 25篇 |
1976年 | 34篇 |
1975年 | 30篇 |
1974年 | 8篇 |
1973年 | 13篇 |
排序方式: 共有2492条查询结果,搜索用时 15 毫秒
91.
Nayu Ikeda David Sapienza Ramiro Guerrero Wichai Aekplakorn Mohsen Naghavi Ali H Mokdad Rafael Lozano Christopher JL Murray Stephen S Lim 《Bulletin of the World Health Organization》2014,92(1):10-19C
Objective
To examine hypertension management across countries and over time using consistent and comparable methods.Methods
A systematic search identified nationally representative health examination surveys from 20 countries containing data from 1980 to 2011 on blood pressure measurements, the diagnosis and treatment of hypertension and its control with antihypertensive drugs. For each country, the prevalence of hypertension (i.e. systolic blood pressure ≥ 140 mmHg or antihypertensive use) and the proportion of hypertensive individuals whose condition was diagnosed, treated or controlled with medications (i.e. systolic pressure < 140 mmHg) were estimated.Findings
The age-standardized prevalence of hypertension varied between countries: for individuals aged 35 to 49 years, it ranged from around 12% in Bangladesh, Egypt and Thailand to around 30% in Armenia, Lesotho and Ukraine; for those aged 35 to 84 years, it ranged from 20% in Bangladesh to more than 40% in Germany, the Russian Federation and Turkey. The age-standardized percentage of hypertensive individuals whose condition was diagnosed, treated or controlled was highest in the United States of America: for those aged 35 to 49 years, it was 84%, 77% and 56%, respectively. Percentages were especially low in Albania, Armenia, the Islamic Republic of Iran and Turkey. Although recent trends in prevalence differed in England, Japan and the United States, treatment coverage and hypertension control improved over time, particularly in England.Conclusion
Globally the proportion of hypertensive individuals whose condition is treated or controlled with medication remains low. Greater efforts are needed to improve hypertension control, which would reduce the burden of noncommunicable diseases. 相似文献92.
Introduction
The aim of this study was to evaluate the kinematics of 2 reciprocating motors and compare it with manufacturers' declared values.Methods
VDW Silver (VDW, Munich, Germany) and ATR Tecnika (Tecnika, Pistoia, Italy) were used in the study in 5 working modes: continuous rotation at 400 rpm on VDW Silver and ATR Tecnika and reciprocating motion on ATR Tecnika at 400 rpm and on VDW Silver in Reciproc and WaveOne mode. The polishing disk with an optical target was inserted in the contra-angle and recorded with a 1000–frames per second video camera. The direction and the amount of rotation were analyzed by computer, and the following kinematics parameters were calculated: engaging and disengaging angles, cycle rotational speeds, engaging and disengaging rotational speeds, net cycle angle, total cycle angle, and number of cycles to complete full rotation. One-way analysis of variance followed by planned pair-wise comparisons was used to compare kinematics parameters. The alpha error was set to 0.05.Results
Analysis of variance revealed a difference between actual and set values of all 3 reciprocating modes in all kinematics parameters (P < .001). No significant difference between the actual engaging angle of Reciproc and that of the WaveOne mode was found. For reciprocating motion on the ATR Tecnika at 400 rpm, the actual engaging and disengaging angles were 8- and 9-fold greater, respectively, compared with set angles (P < .001).Conclusions
The kinematics of reciprocating instrumentation is more complex than it seems as described only with angles and rotational speed. Actual kinematics values differ from manufacturers' declared values. 相似文献93.
B-cell growth factor receptor expression and B-cell growth factor response of leukemic B cell precursors and B lineage lymphoid progenitor cells 总被引:8,自引:1,他引:8
Uckun FM; Fauci AS; Heerema NA; Song CW; Mehta SR; Gajl-Peczalska K; Chandan M; Ambrus JL 《Blood》1987,70(4):1020-1034
The purpose of this study was to analyze the expression of B cell growth factor (BCGF) receptors and to elucidate the biologic effects of biochemically purified natural BCGF at the B cell precursor stage of human B lineage lymphoid differentiation. The specific binding of radioiodinated high-mol-wt BCGF (125I-HMW-BCGF) and low-molecular-wt BCGF (125I-LMW-BCGF) to fresh marrow blasts from B cell precursor acute lymphoblastic leukemia (ALL) patients was initially investigated. The estimated number of radioiodinated BCGF molecules bound per blast ranged from undetectable to 24.3 X 10(3) for HMW-BCGF, and from 11.5 X 10(3) to 457.8 X 10(3) for LMW-BCGF. In 3H-TdR incorporation assays, 75% of cases showed a significant response to LMW-BCGF with a median stimulation index of 9.3. By comparison, only 33% of cases showed a significant response to HMW-BCGF with a median stimulation index of 2.4. Subsequently, B cell precursor colony assays were performed to assess and compare the biologic effects of BCGF on leukemic B lineage lymphoid progenitor cells. Among 28 cases studied, 57% responded to both HMW-BCGF and LMW-BCGF, 21% responded only to LMW-BCGF, and the remaining cases showed no proliferative response to either growth factor. The response patterns of virtually pure populations of FACS- sorted leukemic B cell precursors were essentially identical to the proliferative responses of unsorted leukemic B-cell precursors. Synergistic effects between HMW-BCGF and LMW-BCGF were observed in 80% of the cases that responded to both. The numbers of cell-bound radioiodinated BCGF molecules, the stimulation indices, as well as the number of B cell precursor colonies in BCGF-stimulated cultures showed a marked interpatient variation. Patients with structural chromosomal abnormalities (SCAs) involving 12p11-13 or patients with a Philadelphia chromosome showed a greater HMW-BCGF response at the level of leukemic progenitor cells than did other patients (P = .02). The LMW-BCGF response was significantly greater for patients with SCA than for patients without SCA (P = .04). The response of leukemic progenitor cells to HMW-BCGF or LMW-BCGF did not correlate with sex, age, disease status, FAB morphology, WBC at diagnosis, or immunophenotype. To our knowledge, this study represents the first detailed analyses of BCGF receptor expression and BCGF effects in B cell precursor ALL. The data presented provide direct evidence for the expression of functional receptors for both HMW-BCGF and LMW-BCGF in B cell precursor ALL. 相似文献
94.
K Nandar LW Ang J Tey L James KM Kyi Win CBE Chee OT Ng JL Cutter YT Wang 《HIV medicine》2018,19(1):59-64
Cross‐matching of records between Singapore's tuberculosis and HIV registries showed that 3.3% of individuals with tuberculosis (TB) were coinfected with HIV (2000?2014), the TB incidence among individuals with HIV infection was 1.65 per 100 person‐years, and 53% of coinfections were diagnosed within 1 month of each other. The findings supported joint prevention programmes for early diagnosis and treatment. 相似文献
95.
AMP-18,一种新发现的胃黏膜保护因子 总被引:3,自引:0,他引:3
AMP-18是一种新发现的由胃腺体上皮细胞合成的小分子蛋白质,独特表达于胃黏膜,机体其他部位少见,胃癌组织中表达缺失.AMP-18 由185个氨基酸组成,除去N端信号肽(20个氨基酸)后大小约18 ku,第54-150个氨基酸组成高度保守的结构域(BRICHOS区域)承担主要的生理功能.AMP-18由胃腺体上皮细胞以胞吐的方式分泌到胃黏液中,他的合成和分泌与个体生长发育有关,并受福斯高林、吲哚美辛、地塞米松等药物的影响.目前发现 AMP-18的生理功能主要有促进胃黏膜上皮细胞的有丝分裂,促进细胞的迁徙,促胃肠黏膜损伤的修复,保持胃肠黏膜的完整等. 相似文献
96.
In the last decade, multiple imaging technologies have been developed that improve visualization of the mucosal, mural, and perienteric inflammation associated with inflammatory bowel diseases. Whereas these technologies have traditionally been used to detect and stage suspected enteric inflammation, we review new, emerging roles in detecting clinically occult inflammation (in asymptomatic patients) and inflammatory complications, predicting response prior to therapy, assessing response after therapy, and enteric healing. We compare the relative performance of these technologies in detecting inflammation, focusing on their advantages and disadvantages and how they might complement each other. We also discuss their potential benefits for patients and clinical trials, reviewing technologic developments and areas of research that could provide important insights into the pathophysiology of inflammatory bowel diseases-related enteric inflammation. 相似文献
97.
Prevention of graft-versus-host disease by a novel immunosuppressant, PG490-88, through inhibition of alloreactive T cell expansion 总被引:5,自引:0,他引:5
BACKGROUND: PG490-88 is a water soluble, semisynthetic derivative of a novel compound PG490 (triptolide) purified from the Chinese herb Tripterygium Wilfordii Hook F. METHODS: PG490-88 was administrated into recipient mice in a model (B10.D2-->BALB/c) of lethal graft-versus-host disease (GVHD) to study the effects of PG490-88 on GVHD and on the various steps involved in the pathological course of GVHD. RESULTS: Injection of PG490-88 i.p. at a dose of 0.535 mg/kg/day for the first 3 weeks after transplantation protected all the recipients from developing GVHD up to 100 days after transplantation. PG490-88 inhibited in vivo both CD4+Vbeta3+ and CD8+Vbeta3+ T cell (alloreactive T cells in this model) expansion in the spleen by 64.09 and 34.02%, respectively, at the time when Vbeta3+ cell expansion was in the logarithmic phase (day 3 after transplantation). Intracellular cytokine staining without further in vitro activation demonstrated 47.42% inhibition of IL-2 production among CD4+ spleen cells in PG490-88-treated mice as compared to GVHD control on day 3 after transplantation. In contrast, CD25 (alpha chain of interleukin-2 receptor) expression did not differ. CONCLUSIONS: PG490-88 is highly effective in prevention of murine GVHD. The immunosuppressive effect of PG490-88 is mediated by inhibition of alloreactive T cell expansion through interleukin-2 production. 相似文献
98.
99.
P Valenzuela MS Saiz Puente JL Valero R Azorín R Ortega R Guijarro 《BJOG : an international journal of obstetrics and gynaecology》2009,116(3):436-441
Objective To evaluate the repair techniques of continuous and interrupted methods for episiotomy or perineal tears.
Design A randomised controlled trial.
Setting The Hospital Universitario Principe de Asturias, a state hospital belonging to the community of Madrid.
Sample Four hundred forty-five women who had undergone vaginal deliveries with episiotomies or second-grade tearing of the perineum between September 2005 and July 2007.
Methods One group was repaired with continuous, nonlocking sutures involving the vagina, perineum, and subcutaneous tissues. The other group had continuous, locking sutures of the vagina, interrupted sutures in the perineal muscles, and interrupted transcutaneous sutures. The threads used for stitching were identical in both groups.
Main outcome measures The participants were questioned regarding the sensation of pain and the use of painkillers on the second and the tenth days, and 3 months postpartum.
Results When comparing the group with continuous suture to the group with interrupted sutures, the differences included less repair time (1 minute; P = 0.017) and less suture material used (relative risk [RR], 3.2, 95% CI: 2.6–4.0). The comparison of pain on the second and tenth days, and 3 months postpartum were not statistically different between the two techniques (RR, 1.08, 95% CI: 0.74–1.57; RR, 0.96, 95% CI: 0.59–1.55; and RR, 0.68, 95% CI: 0.19–2.46, respectively).
Conclusions Although we did not demonstrate that one technique was better than the other in the incidence of pain in the short or long term, we showed that episiotomy and perineal tear repairs with continuous suturing were quicker and used less suture material without an increase in complication than interrupted suturing. 相似文献
Design A randomised controlled trial.
Setting The Hospital Universitario Principe de Asturias, a state hospital belonging to the community of Madrid.
Sample Four hundred forty-five women who had undergone vaginal deliveries with episiotomies or second-grade tearing of the perineum between September 2005 and July 2007.
Methods One group was repaired with continuous, nonlocking sutures involving the vagina, perineum, and subcutaneous tissues. The other group had continuous, locking sutures of the vagina, interrupted sutures in the perineal muscles, and interrupted transcutaneous sutures. The threads used for stitching were identical in both groups.
Main outcome measures The participants were questioned regarding the sensation of pain and the use of painkillers on the second and the tenth days, and 3 months postpartum.
Results When comparing the group with continuous suture to the group with interrupted sutures, the differences included less repair time (1 minute; P = 0.017) and less suture material used (relative risk [RR], 3.2, 95% CI: 2.6–4.0). The comparison of pain on the second and tenth days, and 3 months postpartum were not statistically different between the two techniques (RR, 1.08, 95% CI: 0.74–1.57; RR, 0.96, 95% CI: 0.59–1.55; and RR, 0.68, 95% CI: 0.19–2.46, respectively).
Conclusions Although we did not demonstrate that one technique was better than the other in the incidence of pain in the short or long term, we showed that episiotomy and perineal tear repairs with continuous suturing were quicker and used less suture material without an increase in complication than interrupted suturing. 相似文献
100.
北京市社区妇女人乳头瘤病毒感染率及其对HPV和疫苗认知情况的调查分析 总被引:2,自引:0,他引:2
[目的]评估北京市社区妇女人乳头瘤病毒(HPV)的感染率;调查社区人群对HPV的认知情况以及对HPV疫苗接种的态度。[方法]采用横断面调查方法,对北京市展览路社区15 ̄54岁女性进行HPV认知和流行病学问卷调查,并留取了宫颈脱落细胞或会阴部标本进行HPV DNA检测。[结果]1013名女性接受了问卷调查,832例HPV DNA检测结果纳入了统计学分析。HPV总检出率为15.38%,高、低危型HPV感染率分别为13.34%和3.25%,同时感染高、低危型HPV的检出率为1.20%。1013名调查对象中有30.7%听说过HPV,其中51.78%知道HPV感染与宫颈癌有关;HPV的知晓率与年龄和教育程度有关(P〈0.05);经过简单宣教后,75.91%愿意接种HPV疫苗。[结论]北京市社区妇女HPV现患率较高,对HPV的知晓率也较高。开展公众健康教育,提高人群的认识水平是疫苗计划获得成功的关键因素。 相似文献