全文获取类型
收费全文 | 15756篇 |
免费 | 854篇 |
国内免费 | 495篇 |
专业分类
耳鼻咽喉 | 72篇 |
儿科学 | 489篇 |
妇产科学 | 301篇 |
基础医学 | 1202篇 |
口腔科学 | 121篇 |
临床医学 | 2132篇 |
内科学 | 3041篇 |
皮肤病学 | 78篇 |
神经病学 | 664篇 |
特种医学 | 555篇 |
外科学 | 1558篇 |
综合类 | 2260篇 |
预防医学 | 1741篇 |
眼科学 | 188篇 |
药学 | 1742篇 |
12篇 | |
中国医学 | 558篇 |
肿瘤学 | 391篇 |
出版年
2024年 | 24篇 |
2023年 | 218篇 |
2022年 | 438篇 |
2021年 | 625篇 |
2020年 | 550篇 |
2019年 | 529篇 |
2018年 | 529篇 |
2017年 | 457篇 |
2016年 | 471篇 |
2015年 | 456篇 |
2014年 | 1127篇 |
2013年 | 1365篇 |
2012年 | 883篇 |
2011年 | 1040篇 |
2010年 | 809篇 |
2009年 | 695篇 |
2008年 | 782篇 |
2007年 | 709篇 |
2006年 | 565篇 |
2005年 | 534篇 |
2004年 | 446篇 |
2003年 | 415篇 |
2002年 | 358篇 |
2001年 | 289篇 |
2000年 | 234篇 |
1999年 | 207篇 |
1998年 | 220篇 |
1997年 | 220篇 |
1996年 | 186篇 |
1995年 | 151篇 |
1994年 | 150篇 |
1993年 | 120篇 |
1992年 | 113篇 |
1991年 | 119篇 |
1990年 | 103篇 |
1989年 | 105篇 |
1988年 | 86篇 |
1987年 | 90篇 |
1986年 | 72篇 |
1985年 | 87篇 |
1984年 | 101篇 |
1983年 | 56篇 |
1982年 | 81篇 |
1981年 | 42篇 |
1980年 | 47篇 |
1979年 | 36篇 |
1978年 | 27篇 |
1977年 | 37篇 |
1976年 | 33篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
4 背景
强化降脂使低密度脂蛋白胆固醇(low-density lipoprotein cholesterol,LDL-C)低于指南推荐的水平将使急性冠脉综合征患者获益。但强化降脂使稳定性冠心病患者的LDL-C低于100mg/dL是否安全和有效尚不清楚。 相似文献
72.
Objective To determine the concentrations of cholesterol sulfate ( CS) in human sera and pla-cental villi during the course of pregnancy. And to analyze its inhibitory activity on thrombin and further characterize the functional significance of CS. Methods The concentrations of CS were determined by thin-layer chromatog-raphy (TLC) on 60 cases of normal pregnant women and 30 cases of normal placental villi. The effect of CS in human sera on the activity of thrombin was analyzed. Results The concentrations of CS in human sera gradually increased from the first to third trimester of gestation with a correlation coefficient of 0. 69, and a correlation between the concentration of CS and weeks of gestation (P <0. 01). CS was also contained in the placental villi, and its concentrations at the second and third trimester of gestations were 4. 7 and 6. 2-fold of that at the first trimester of gestation. CS inhibited the activity of thrombin. Conclusion Placental CS is one of the sources of CS in the serum , pr 相似文献
73.
抗凝治疗肺心病血栓前状态的临床研究 总被引:6,自引:2,他引:4
目的探讨肺心病患者的血栓前状态,观察并分析低分子肝素抗凝干预的疗效。方法将54倒肺心病患者分为低分子肝素治疗组和常规治疗组各27例。分别检测治疗前后血浆血管性假血友病因子(VWF)、血浆凝血酶片段1 2(F1 2)、纤堆蛋白原(Fg)、血小板颗粒膜蛋白(GMP-140)和D-二聚体(DD)。结果肺心病患者VWF、F1 2、Fg、GMP-140、DD血浆浓度显著高于对照组;肺心病治疗组经LMWH治疗后上述各凝血分子标记物及PaCO2明显降低。而PaO2显著增高。常规组虽血气指标略有改善。但凝血分子标记物未见改善。结论尽早检测肺心病血栓前状态,及时给予低分子肝素抗凝干预,有望从根本上改善肺心病惠性加重期患者的不良预后。 相似文献
74.
Summary An anatomical study of the lumbar apophyseal joints was carried out to facilitate recognition of facet joint lesions, which we now examine routinely by percutaneous arthrography. Special attention was given to the configuration of the different compartments of the joint space and to its relationships with the contents of the intervertebral foramen. The abnormalities seen on lumbar facet joint arthrography are very varied; two major groups should be stressed: synovial fringe hypertrophy and pseudodiverticular synovial ectasia. The percutaneous approach to lumbar facet joint arthrography allows it to be used a therapeutic measure, with injection of anti-inflammatory drugs into the joint space, the beneficial effects of which were confirmed in our series. The precision, efficiency and cost-effectiveness of this outpatient technique justify and should encourage its more widespread application in the diagnosis and treatment of low back pain. 相似文献
75.
T. Schäfer S. Ruhdorfer† L. Weigl† D. Wessner† J. Heinrich‡ A. Döring‡ H.-E. Wichmann‡§ J. Ring†¶ 《Clinical and experimental allergy》2003,33(10):1360-1367
BACKGROUND: The increase in allergic diseases is still unexplained. It was hypothesized that the intake of unsaturated fatty acids is a contributing cause of this development. We investigated the relationship between serum cholesterol levels, intake of polyunsaturated fatty acids (PUFA) and manifestations of atopy in a population-based setting. METHODS: A nested case-control study was performed within the population of the 3rd MONICA survey in Augsburg (Germany). The serum levels of total, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol of 1537 adults (aged 28-78 years, response 61.4%) and the estimated intake of PUFA in a subset of 139 men were compared with the frequency of a doctor's diagnosis of asthma, allergic rhinoconjunctivitis (AR), atopic eczema (AE) and allergic sensitization as measured by skin prick and Radio Allergo Sorbent Test. FINDINGS: In bivariate analyses, we obtained a negative linear association between total and LDL cholesterol levels and the frequency of AR and sensitization, which was no longer significant after adjustment for important confounders. In contrast, positive linear associations were found between HDL cholesterol levels and AR and AE and, furthermore, between the intake of PUFA and allergic sensitization in men (P<0.01). After adjustment, an increasing risk for atopic diseases with increasing levels of HDL cholesterol and an increasing risk for allergic sensitization with increasing intakes of PUFA remained statistically significant. INTERPRETATION: There is indication that HDL cholesterol also plays a role in the complex interaction of fat intake, metabolism and the manifestation of atopy in adults. These findings may contribute to the understanding of time trends and regional differences of allergies. 相似文献
76.
Christina Frennesson Peter Jakobsson Ulla L. Nilsson 《Documenta ophthalmologica. Advances in ophthalmology》1995,91(1):9-16
A new approach designed to establish the most suitable area for eccentric viewing and to teach and train patients with severe age-related macular degeneration (AMD) to use the eccentric viewing technique is described. Using a computer and video display based system, as well as software written specifically for this purpose, we investigated and trained ten consecutive patients with AMD. The patients were 80.1 ± 5.6 years old, on average. All of them had an absolute central scotoma. Mean visual acuity was 0.035 ± 0.016. After 30 min of testing, instruction and reading on the screen, followed by 2.6 ± 0.69 one-hour training sessions, on average, with the low vision therapist, reading newspaper and book texts with the aid of hyperoculars or aplanatic systems and a very short reading distance, the patients achieved a reading speed of 58.9 ± 19.7 words/min, significantly (p<0.001) higher than the initial speed when reading on the screen, 11.5 ± 4.5 words/min. 相似文献
77.
Yohei Ogawa Makoto Hiura Toru Kikuchi Keisuke Nagasaki Yukie Iwata Makoto Uchiyama 《Clinical Pediatric Endocrinology》2004,13(1):55-58
This study aimed to investigate the levels of serum low-density lipoprotein
cholesterol (LDLC) using direct measurement in healthy Japanese school children. The
subjects were 621 children (325 boys and 296 girls) aged 9 to 10 in the 4th grade, and 688
children (334 boys and 354 girls) aged 12 to 13 in the 7th grade. The levels of serum LDLC
and high-density lipoprotein cholesterol were measured by direct determination (Cholestest
LDL and Cholestest NHDL; Daiichi Pure Chemicals Co., Ltd., Tokyo, Japan). In boys in the
4th grade, the mean, the 75th, the 90th and the 95th percentiles of LDLC levels (mg/dl)
were 91.6, 104, 124 and 134, respectively. In girls in the 4th grade, they were 92.8, 108,
122 and 130. In boys in the 7th grade, they were 83.4, 96, 113 and 123. In girls in the
7th grade, they were 93.0, 106, 126 and 137. Serum LDLC levels in boys in the 7th grade
were lower than those of other groups. The direct measurement of serum LDLC level is
useful for evaluation of dyslipidemia in healthy school children, because the method is
applicable to non-fasting serum. 相似文献
78.
高脂血症对血浆t-PA和PAI-1活性的影响 总被引:2,自引:0,他引:2
目的 探讨高脂血症患者的纤溶系统的变化。方法 选取正常人及高脂血症者,测定其血脂、血浆t—PA和PAI-1活性。结果 高脂血症组比正常人血浆t—PA活性下降,而PAI-1的活性有升高;在TG及LDL-C升高者,其血浆t—PA活性比正常人血浆t—PA活性降低,而血浆PAI-1活性比正常人升高;单纯TC升高者血浆PAI-1活性接近正常人组,而血浆t—PA活性比正常人组明显降低。结论 高脂血症对纤溶系统有一定的影响,其中甘油三酯和LDL-C对纤溶系统的影响更明显,而胆固醇对纤溶系统也有一定的影响。 相似文献
79.
80.
目的 评价低场强磁共振成像对主动脉夹层的诊断价值。方法 对16例主动脉夹层在低场强MRI自旋回波(SE)序列和梯度回波(GRE)表现进行回顾性分析总结,其中,6例经手术病理证实。结果 16例均能清晰显示病变的范围、夹层起始部位、内膜片、真假腔,6例假腔内显示血栓。结论 低场强MRI作为一种无创性检查能对主动脉夹层作出准确及时的诊断。 相似文献