全文获取类型
收费全文 | 242126篇 |
免费 | 21648篇 |
国内免费 | 6439篇 |
专业分类
耳鼻咽喉 | 3371篇 |
儿科学 | 4532篇 |
妇产科学 | 3942篇 |
基础医学 | 24568篇 |
口腔科学 | 8049篇 |
临床医学 | 21685篇 |
内科学 | 24453篇 |
皮肤病学 | 3059篇 |
神经病学 | 12437篇 |
特种医学 | 6295篇 |
外国民族医学 | 27篇 |
外科学 | 22374篇 |
综合类 | 39116篇 |
现状与发展 | 21篇 |
一般理论 | 25篇 |
预防医学 | 29448篇 |
眼科学 | 2548篇 |
药学 | 23214篇 |
351篇 | |
中国医学 | 27539篇 |
肿瘤学 | 13159篇 |
出版年
2024年 | 1043篇 |
2023年 | 4690篇 |
2022年 | 8940篇 |
2021年 | 11810篇 |
2020年 | 11383篇 |
2019年 | 12572篇 |
2018年 | 11074篇 |
2017年 | 9890篇 |
2016年 | 8903篇 |
2015年 | 8534篇 |
2014年 | 15834篇 |
2013年 | 16377篇 |
2012年 | 14348篇 |
2011年 | 15297篇 |
2010年 | 12469篇 |
2009年 | 10824篇 |
2008年 | 10216篇 |
2007年 | 10331篇 |
2006年 | 8975篇 |
2005年 | 7626篇 |
2004年 | 6500篇 |
2003年 | 5873篇 |
2002年 | 4540篇 |
2001年 | 3864篇 |
2000年 | 3418篇 |
1999年 | 2823篇 |
1998年 | 2405篇 |
1997年 | 2200篇 |
1996年 | 1788篇 |
1995年 | 1691篇 |
1994年 | 1566篇 |
1993年 | 1377篇 |
1992年 | 1187篇 |
1991年 | 1100篇 |
1990年 | 961篇 |
1989年 | 915篇 |
1988年 | 815篇 |
1987年 | 729篇 |
1986年 | 645篇 |
1985年 | 2013篇 |
1984年 | 2259篇 |
1983年 | 1408篇 |
1982年 | 1885篇 |
1981年 | 1323篇 |
1980年 | 1110篇 |
1979年 | 969篇 |
1978年 | 773篇 |
1977年 | 595篇 |
1976年 | 726篇 |
1975年 | 486篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Teng-Yi Huang Hsiao-Wen Chung Fu-Nien Wang Cheng-Wen Ko Cheng-Yu Chen 《Magnetic resonance in medicine》2004,51(2):243-247
In this work the feasibility of separating fat and water signals using the balanced steady-state free precession (SSFP) technique is demonstrated. The technique is based on the observation (Scheffler and Hennig, Magnetic Resonance in Medicine 2003;49:395-397) that at the nominal values of TE = TR/2 in SSFP imaging, phase coherence can be achieved at essentially only two orientations (0 degrees and 180 degrees ) relative to the RF pulses in the rotating frame, under the assumption of TR < T2, and independently of the SSFP angle. This property allows in-phase and out-of-phase SSFP images to be obtained by proper choices of the center frequency offset, and thus allows the Dixon subtraction method to be utilized for effective fat-water separation. The TR and frequency offset for optimal fat-water separation are derived from theories. Experimental results from healthy subjects, using a 3.0 Tesla system, show that nearly complete fat suppression can be accomplished. 相似文献
32.
中风毒邪论是一种与传统中医中风病理有所不同的理论 ,在中风毒邪论指导下形成解毒通络方是较为理想的神经保护剂 ,可解决目前神经保护治疗的主要障碍 ,有望成为提高中医治疗中风急性期疗效的关键 相似文献
33.
Robert M. Levy Roman Saikovsky Evgeniya Shmidt Alexander Khokhlov Bruce P. Burnett 《Nutrition Research》2009
Flavocoxid (Limbrel), a proprietary mixture of flavonoid molecules (baicalin and catechin), was tested against a traditional nonsteroidal anti-inflammatory drug, naproxen, for the management of the signs and symptoms of moderate osteoarthritis (OA) in humans. Discomfort and global disease activity were used as the primary end points, and safety assessments were also taken for both treatments as a secondary endpoint. In this double-blind study, 103 subjects were randomly assigned to receive either flavocoxid [500 mg twice daily (BID)] or naproxen (500 mg BID) in a 1-month onset of action trial. Outcome measures included the short Western Ontario and McMaster University Osteoarthritis Index, subject Visual Analogue Scale for discomfort and global response, and investigator Visual Analogue Scale for global response and fecal occult blood. Both flavocoxid and naproxen showed significant reduction in the signs and symptoms of knee OA (P ≤ .001). There were no statistically detectable differences between the flavocoxid and naproxen groups with respect to any of the outcome variables. Similarly, there were no statistically detectable differences between the groups with respect to any adverse event, although there was a trend toward a higher incidence of edema and nonspecific musculoskeletal discomfort in the naproxen group. In this short-term pilot study, flavocoxid was as effective as naproxen in controlling the signs and symptoms of OA of the knee and would present a safe and effective option for those individuals on traditional nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors. A low incidence of adverse events was reported for both groups. 相似文献
34.
大学新生心理健康状况的调查研究 总被引:2,自引:0,他引:2
赵可军 《山东医学高等专科学校学报》2004,26(3):209-211
目的 了解大学新生的心理健康状况 ,探讨提高其心理健康水平的措施。方法 采用大学生人格问卷(UPI) ,以班级为单位 ,在新生正式上课两周以后进行测试。结果 学生一类筛选率 9.2 4 %。UPI关键题选择中 ,以常常失眠占的比例最高 ,想轻生的比例最低 (P <0 .0 5 )。UPI附加题选择中 ,以自身健康方面有问题及有健康或心理卫生方面想要咨询的问题较多 (P <0 .0 5 )。选择“想轻生”的男生的比例略高于女生 ,选择“常常失眠”的女生的比例却明显高于男生 (P <0 .0 5 ) ;选择“常常失眠”、“对任何事情都不感兴趣”和“感觉自己的过去及家庭不幸”的农村学生的比例都高于城市学生 (P <0 .0 5 )。选择“想轻生”和“对任何事情都不感兴趣”的独生子女的比例明显高于非独生子女 ,而选择“自己的过去和家庭是不行的”和“常常失眠”的非独生子女的比例又明显高于独生子女 (P <0 .0 5 )。结论 单亲家庭学生、残疾学生、家庭经济困难学生、独生子女学生是心理问题高危人群 相似文献
35.
LESLEY BOULTON MB CHB FRACO DO Ophthalmologist 《Clinical & experimental ophthalmology》1986,14(4):365-371
The Low Vision Clinic at the Palmerston North Hospital has now been oerating for 70 years. Over the course of these ten years a number of factors have emerged which can be as readily applied to general ophthalmological practice as to low vision practice. The philosophy of low vision care is one of which all ophthalmologists should be aware and includes factors to be taken into account when dealing with children, people in the workplace, and everyday factors involved in daily living activities, all of which are equally relevant in routine ophthalmological practice. This paper endeavours to share some thoughts on these factors and also discusses means by which the visually handicapped can be helped in areas where specialist low vision services are not readily available. 相似文献
36.
37.
目的 探讨老年人急性阑尾炎的临床特点,更好地把握腹腔镜阑尾切除(LA)术的方法和特点。方法 回顾分析50例老年人急性阑尾炎LA的临床资料。结果 LA均获成功,患者全部治愈,无严重的并发症发生,肠功能恢复时间及住院时间均缩短。结论 老年人反应迟钝,阑尾炎进展快,易发生坏疽及穿孔,合并症多,手术风险较高,LA是安全、可行的,除个别腹膜后阑尾炎外,其余均可施行LA。 相似文献
38.
Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D100) were determined and vessels were set up to a normalized internal diameter (0.9 D100). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells. 相似文献
39.
神经肽Y(NPY)是广泛分布于中枢神经系统和外周神经各部位的神经肽类物质。本实验观察NPY在体外对几种免疫细胞活性的直接作用。结果表明,NPY对小鼠T淋巴细胞丝裂原反应性和NK细胞的杀伤活性均无明显影响(P>0.05),对巨噬细胞分泌溶菌酶有明显抑制作用(P<0.05);而对B淋巴细胞丝裂原反应性则有明显的促进作用(P<0.05)。上述结果提示,NPY对部分免疫细胞功能的影响因细胞种类而异。 相似文献
40.
Examined are several measures currently used in the assessment of child abuse, sexual abuse, and trauma. These measures include
structured clinical interviews, self report measures, screening inventory, symptom checklist, and some measures that include
decision making properties. Issues and implications for clinical practice are explored. 相似文献