全文获取类型
收费全文 | 224609篇 |
免费 | 20683篇 |
国内免费 | 14751篇 |
专业分类
耳鼻咽喉 | 1937篇 |
儿科学 | 3140篇 |
妇产科学 | 3282篇 |
基础医学 | 24839篇 |
口腔科学 | 3567篇 |
临床医学 | 29051篇 |
内科学 | 33956篇 |
皮肤病学 | 2899篇 |
神经病学 | 11481篇 |
特种医学 | 8136篇 |
外国民族医学 | 99篇 |
外科学 | 21645篇 |
综合类 | 37601篇 |
现状与发展 | 42篇 |
一般理论 | 17篇 |
预防医学 | 15956篇 |
眼科学 | 6005篇 |
药学 | 24828篇 |
199篇 | |
中国医学 | 13521篇 |
肿瘤学 | 17842篇 |
出版年
2024年 | 840篇 |
2023年 | 3392篇 |
2022年 | 8656篇 |
2021年 | 10905篇 |
2020年 | 8128篇 |
2019年 | 7256篇 |
2018年 | 7475篇 |
2017年 | 6992篇 |
2016年 | 6681篇 |
2015年 | 9987篇 |
2014年 | 12370篇 |
2013年 | 11939篇 |
2012年 | 17342篇 |
2011年 | 18771篇 |
2010年 | 12385篇 |
2009年 | 10015篇 |
2008年 | 12427篇 |
2007年 | 12012篇 |
2006年 | 11607篇 |
2005年 | 11057篇 |
2004年 | 7719篇 |
2003年 | 7299篇 |
2002年 | 6142篇 |
2001年 | 5304篇 |
2000年 | 5007篇 |
1999年 | 4933篇 |
1998年 | 3139篇 |
1997年 | 3069篇 |
1996年 | 2207篇 |
1995年 | 1996篇 |
1994年 | 1736篇 |
1993年 | 1149篇 |
1992年 | 1584篇 |
1991年 | 1395篇 |
1990年 | 1203篇 |
1989年 | 1069篇 |
1988年 | 884篇 |
1987年 | 866篇 |
1986年 | 656篇 |
1985年 | 578篇 |
1984年 | 333篇 |
1983年 | 219篇 |
1982年 | 160篇 |
1981年 | 165篇 |
1980年 | 113篇 |
1979年 | 155篇 |
1978年 | 91篇 |
1976年 | 68篇 |
1975年 | 65篇 |
1974年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
X F Sun H Zhang X C Wu Y M Han G Q Hou M S Xian 《Acta oncologica (Stockholm, Sweden)》1992,31(1):37-40
The microcirculatory architecture of normal tissue, transitional mucosa and adenocarcinoma of the human colon was investigated with microvascular corrosion casting (MVCC) combined with scanning electron microscopy (SEM). The study showed that the capillaries within the normal mucosa were arranged in a regular hexagonal pattern around the mucosal glands and that the microvessels of transitional mucosa mostly had lost the typical hexagonal pattern and become slightly wider in diameter. The microvessels in the tumor periphery were increased in number and disorganized, and presented large variation in morphology with claw-like formations, widened sinuses, diverticula and appendixoid patterns. Microvessels were lacking in the central areas of tumors. These morphological alterations may serve as additional indicators of tumor development. 相似文献
82.
The authors compared the inhaled methacholine and exercise responses in 22 stable unmedicated asthmatic patients. The exercise and methacholine challenges were performed at one to three week intervals. Bronchial responsiveness to methacholine was measured in relation to the concentration of methacholine (PC20M). The response to exercise was expressed as the percentage of fall in FEV1, from the pre-exercise FEV1 The findings showed that 21 of 22 subjects demonstrated a fall in FEV1, of more than 20% after methacholine challenge, while only 9/22 subjects experienced a similar decrease in FEV1. All 9 of these positive response exercise cases completed three consecutive exercise challenges prior to the methacholine challenge. Of these cases, five were refractory to the repeated exercise challenge, and the PD20M at the nonexercise stage was significantly lower than the postexercise state. In fact, the methacholine challenge sensitivity actually decreased (PD20 increased) after repeated exercise. The authors concluded that methacholine seems to be a more sensitive bronchial provocation test than exercise. Second, only 55.6% of the exercise test-positive subjects were refractory to the second exercise challenge. Therefore, other factors besides the release of mediators should be considered in exercise induced asthma. Third, methacholine sensitivity actually decreased (PD20 increases) after repeat exercise challenge. 相似文献
83.
本文采用去垢剂透析法成功制备出携载SOD的脂质体(L-SOD),其直径为102nm,对SOD的包裹率为21%,90%以上酶活性存在于脂质体内部。将L-SOD注射到大鼠静脉血中,其半衰期超过4h,明显长于天然SOD(8min)。表明L-SOD优于天然SOD,具有临床应用前景。 相似文献
84.
Lesbianism in China has a long but usually hidden history. This paper examines the historical and literary sources of the past to illustrate the history of lesbianism and then turns to a survey of lesbianism in the China of today. As in the past, lesbianism remains more or less hidden, and comes to light only occasionally. Data for contemporary China comes from a visit to an institution for delinquent young women, recent police records, and contemporary fiction. It has only been in the past 4 or 5 years that it was possible to talk about lesbianism and most lesbians are fearful of becoming identified. 相似文献
85.
86.
诺迪康对心脏活动的药理学作用 总被引:5,自引:0,他引:5
目的 :探讨诺迪康对心脏活动的药理学作用。方法 :运用 ms2 0 0 0多媒体生物信号处理系统 ,经 Straub法制备离体蛙心灌流标本并检测心脏活动 ,利用血流动力学方法检测家兔的心室活动等相关指标。结果 :2 0 9mg/L 诺迪康组的心肌收缩力增强 4 0 .38% (n =2 1,P <0 .0 0 1) ,4 18mg/L 诺迪康组的心肌收缩力增强 76 .4 4 % (n =17,P <0 .0 5 ) ,6 2 7mg/L 诺迪康组的心肌收缩力增强 10 4 .95 % (n =2 5 ,P <0 .0 1) ,对照组的心肌收缩力无明显变化 (n =2 5 ,P >0 .5 ) ;三个实验组及对照组对离体蛙心率均无作用 ,P >0 .0 5 ;家兔血流动力学方面 ,诺迪康组的 dp/dtmax增加了 2 1.0 8% (n =10 ,P <0 .0 5 ) ,其他各指标在对照组及诺迪康组均未见显著变化。结论 :诺迪康能增强心肌收缩力且有明显的剂量效应关系 ,可加速心肌的收缩速度但对心肌舒张无明显影响 相似文献
87.
对16例垂体腺瘤采用单侧鼻前庭切口经蝶切除,效果满意,既可减少手术创伤,又缩短了手术距离,且避免了美容缺陷,是一种设计巧妙,较为实用的手术方法,尤其适用于生长激素腺瘤。 相似文献
88.
为给临床心脏术后监测心淋巴管损伤程度及可能出现的并发症提供参考指标,以手术方法阻断羊心淋巴流并对其血清相关成份进行了测定。实验发现,实验组术后谷草转氨酶(SGOT)、谷丙转氨酶(SGPT)、碱性磷酸酶(AKP)、乳酸脱氢酶(LDH)均有不同程度的增高,以SGOT增高最为明显,术前均值为47.53U,术后2天增至104.20U,高峰出现时间最早,多在术后24小时。血清离子改变中低钾最为突出,血钾在术后2天明显降低(P<0.01),术后7天逐渐恢复,术后14天恢复至术前水平。血清蛋白改变以球蛋白降低、白蛋白/球蛋白比值升高为主。提示心淋巴循环郁滞可导致心肌细胞损伤、毛细血管通透性和结构的改变。不同酶活性的变化对郁滞的敏感度存在着差异。 相似文献
89.
本文报告口服Sumatriptan 100mg对偏头痛急性发作119例次的治疗结果。治疗后4h内显效91例次(76.5%),好转16例次(13.4%),无效12例次(10.1%),总有效率为89.9%。对偏头痛伴随症状恶心、呕吐和畏光、畏声的缓解率分别为94.2%、96%和94.3%。 相似文献
90.
The alpha subunit of the nicotinic acetylcholine receptor (AChR) seems crucial in the pathogenesis of the autoimmune paralysis myasthenia gravis (MG) because it contains both the epitopes that dominate the antibody response against the AChR and those recognized by CD4+ AChR-specific T helper (Th) cells. To define the repertoire of anti-AChR Th cells, we investigated the response of unselected blood CD4+ cells or total lymphocytes, or both, from 22 MG patients to 20-residue overlapping synthetic peptides, screening the complete sequence of human-muscle AChR alpha subunit. Several epitopes were identified. Only the most severely affected patients recognized alpha subunit epitopes, and they were mainly young women. Detection of in vitro AChR-specific CD4+ response was facilitated by removal of the CD8+ cells because in two patients a clear response to several alpha subunit peptide sequences could be detected when CD(8+)-depleted cells were used, while their total peripheral blood mononuclear cell population did not respond to any alpha subunit peptide. Although each patient had a unique pattern of peptide recognition, four immunodominant regions recognized by long-term AChR-specific CD4+ T-cell lines, or flanking peptide sequences, were recognized most frequently (residues 48-67, 101-137, 293-337, and 308-437). 相似文献