全文获取类型
收费全文 | 29734篇 |
免费 | 2590篇 |
国内免费 | 1409篇 |
专业分类
耳鼻咽喉 | 255篇 |
儿科学 | 467篇 |
妇产科学 | 669篇 |
基础医学 | 3591篇 |
口腔科学 | 1015篇 |
临床医学 | 3529篇 |
内科学 | 5199篇 |
皮肤病学 | 295篇 |
神经病学 | 2358篇 |
特种医学 | 1120篇 |
外国民族医学 | 13篇 |
外科学 | 3237篇 |
综合类 | 3448篇 |
现状与发展 | 4篇 |
一般理论 | 4篇 |
预防医学 | 1891篇 |
眼科学 | 787篇 |
药学 | 2548篇 |
24篇 | |
中国医学 | 1152篇 |
肿瘤学 | 2127篇 |
出版年
2024年 | 71篇 |
2023年 | 386篇 |
2022年 | 856篇 |
2021年 | 1150篇 |
2020年 | 833篇 |
2019年 | 810篇 |
2018年 | 891篇 |
2017年 | 814篇 |
2016年 | 747篇 |
2015年 | 1102篇 |
2014年 | 1290篇 |
2013年 | 1310篇 |
2012年 | 1759篇 |
2011年 | 2054篇 |
2010年 | 1383篇 |
2009年 | 1154篇 |
2008年 | 1524篇 |
2007年 | 1504篇 |
2006年 | 1441篇 |
2005年 | 1368篇 |
2004年 | 1122篇 |
2003年 | 1091篇 |
2002年 | 995篇 |
2001年 | 825篇 |
2000年 | 819篇 |
1999年 | 743篇 |
1998年 | 394篇 |
1997年 | 370篇 |
1996年 | 320篇 |
1995年 | 280篇 |
1994年 | 282篇 |
1993年 | 216篇 |
1992年 | 342篇 |
1991年 | 303篇 |
1990年 | 289篇 |
1989年 | 257篇 |
1988年 | 240篇 |
1987年 | 213篇 |
1986年 | 201篇 |
1985年 | 193篇 |
1984年 | 139篇 |
1983年 | 138篇 |
1982年 | 80篇 |
1979年 | 91篇 |
1978年 | 82篇 |
1977年 | 70篇 |
1975年 | 102篇 |
1974年 | 73篇 |
1973年 | 72篇 |
1972年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The results from a cohort study on the incidence of cancer and the mortality in a cohort of 2391 male workers producing magnesium metal are presented. The study population was restricted to employees with more than one year of work experience in the study plant between 1951 and 1974 and the cohort was observed from 1953 to 1984. Altogether 152 new cases of cancer were observed versus 132.6 expected. Six cases of cancer of the lip were found against 2.3 expected, 21 of stomach cancer against 12.8 expected, and 32 of lung cancer against 18.2 expected. A possible causal relation between exposure to factors in the work environment and the development of cancer is discussed. 相似文献
72.
本文观察了52侧(男46,女6)成人尸体臀上动、静脉深上支进入髂嵴情况.臀上动、静脉深上支分为前、中、后支;本文测量了臀上动、静脉深上支的外径及各分支进入髂嵴的距离.臀上动、静脉深上支的分支在髂嵴前部及中部分布较多,前支的分支为3~8支,其中以4~6支者为多见,占78.8±5.5%;中支的分支1~4支,其中以2~3者为多见,占73.1±6.1%.因此,臀上动脉深上支作为游离髂骨移植术取髂嵴的前部和中部较宜. 相似文献
73.
C. Lang J. Reichwein H. Iro T. Treig 《European archives of psychiatry and clinical neuroscience》1989,239(3):188-193
Summary In a 66-year-old woman signs and symptoms of bilateral opercular syndrome (Foix-Chavany-Marie-syndrome) developed progressively over a period of more than 10 years. Facio-linguo-velo-pharyngeo-masticatory diplegia with automatic-vol-untary dissociation was accompanied by motor aphasia and oral apraxia leading to a state of almost complete anarthria. Although it initially resembled the anterior biopercular syndrome there are also features indicating involvement of the posterior opercula. Although the aetiology remains obscure without pathological data, a bilateral focal brain atrophy is assumed. This is probably the first case documented by MRI and SPECT.Supported by the Hirnliga, Heidelberg, Federal Republic of Germany 相似文献
74.
Effect of converting enzyme inhibitors on tissue converting enzyme and angiotensin II: therapeutic implications 总被引:1,自引:0,他引:1
Local tissue renin-angiotensin systems have recently been discovered in various organs, and evidence is accumulating that inhibition of these local renin-angiotensin systems may contribute to the actions of converting enzyme (CE) inhibitors. Measurements of CE activity and angiotensin II concentrations revealed that after oral administration of CE inhibitors, CE was inhibited not only in lung vascular endothelium and blood, but also in the heart, kidney, vascular wall, brain and other organs. The functional significance of tissue CE inhibition is suggested first by the antihypertensive effect of brain CE inhibition in spontaneously hypertensive rats, second by the concomitant persistence of blood pressure decrease and CE inhibition in vascular wall and kidney after long-term oral CE inhibitor treatment and third by ex vivo experiments demonstrating marked effects of oral CE inhibitor pretreatment on cardiac function in isolated rat hearts. Local inhibition of tissue renin-angiotensin systems may be an important factor involved in the beneficial effects of CE inhibitors in such cardiovascular diseases as arterial hypertension, congestive heart failure and cardiac arrhythmias. 相似文献
75.
Qiu Ming-cai邱明才 Li Song-lingand Bai Cheng-jiang白成江李松岭 Zhang Nai-xin张乃鑫Department of Endocrinology the First AffiliatedHospital Tianjin Medical College Tianjin 《中华医学杂志(英文版)》1987,100(4):330-332
Histomorphometric study was made on a series
of sections of undecalcified epiphyseal femoral
specimens from rats with experimental fluorosis. The
results revealed osteosclerosis in Group A (5 ppm)
being more severe than that in Group B (25 ppm)
With the increase of fluoride dose, the parameters
fell down instead of increased in parallel. There is
seemingly a threshold over which osteosclerosis in
fluorosis becomes less severe. In contrast to Bely's
conclusion the authors proposed that, fluoride toxi-
city, besides decreasing the number of osteoblasts,
may also activate the osteoblasts. The number of
osteoblasts may be increased with relative lower
dose of fluoride also. The net outcome is the in
crement in bone volume. When toxic dose of
fluoride is higher enough (higher than the proposed
threshold), however, the number of osteoblasts and
its activity are inhibited. So are the osteocytes. This
interpretation may be the cytological basis for
osteosclerosis in the experimental fluorosis. 相似文献
76.
协同刺激分子CD28在结核杆菌抗原体外激活人外周血γδT细胞中的作用 总被引:2,自引:0,他引:2
目的 :为了探讨CD2 8协同刺激分子在结核杆菌 (Mtb)低分子多肽抗原体外激活人外周血γδ T细胞中的作用。方法 :采用激发型抗CD2 8单抗模拟第二信号 ,Mtb低分子多肽抗原作为刺激原 ,对纯化的人外周血T细胞进行体外刺激和培养 ;用流式细胞仪检测γδ T细胞上CD2 8分子的表达、γδ T细胞的增殖效应及活化的γδ T细胞上CD6 9分子的表达。结果 :人外周血γδ T细胞中有 5 0 %左右表达CD2 8分子 ;抗CD2 8单抗协同Mtb抗原可刺激γδ T细胞的活化和增殖 ;但抗CD2 8单抗或Mtb抗原单独刺激则无作用。活化的γδ T细胞表面表达CD6 9分子。结论 :Mtb抗原在选择性活化人外周血γδ T细胞时需要第二信号的参与 ;CD2 8在Mtb抗原激活γδ T细胞时可提供协同刺激信号 ;CD6 9可作为γδ T细胞的早期活化标志。 相似文献
77.
78.
Clival chordoma presenting with acute brain stem hemorrhage. 总被引:1,自引:0,他引:1
A D Levi W Kucharczyk A P Lang H Schutz 《The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques》1991,18(4):515-518
The authors present a case of a 29-year-old man who developed rapidly progressive cranial nerve palsies and a right hemiparesis secondary to a pontine hemorrhage. The rare but correct diagnosis of a clival chordoma which had invaded the brain stem and subsequently hemorrhaged was based on computed tomography and magnetic resonance imaging. The diagnosis was confirmed at surgery when the patient underwent a successful operative decompression of tumor and clot from the pons via a sub-occipital craniotomy. This represents the first case of a clival chordoma to hemorrhage into the brain stem, which was diagnosed preoperatively and the patient survived. 相似文献
79.
神经活素对Pc12细胞作用的初步观察 总被引:1,自引:0,他引:1
从胎脑、颌下腺、肌肉组织中制备神经活素。其性能同脑活素一样:可促进Pc12细胞的突起生长,提高其胞浆内乳酸脱氢酶活性,电泳显示二者有相同的三条带。提示:神经活素有可能替代脑活素应用于临床。 相似文献
80.
M. Ito T. F. Lang M. Jergas M. Ohki M. Takada T. Nakamura K. Hayashi H. K. Genant 《Calcified tissue international》1997,61(2):123-128
This study examined trabecular bone mineral density (BMD) in Japanese women with and without spinal fracture, and compared
the results to American women with and without fracture. The quantitative computed tomography (QCT) systems used at the University
of California, San Francisco (UCSF) and at Nagasaki University were cross-calibrated. Normative BMD was assessed with the
K2HPO4 liquid phantom in 538 Americans aged 20–85 years, and with the B-MAS200 phantom in 577 Japanese aged 20–83 years. These BMD
were adjusted for use with the Image Analysis solid phantom using the result of cross-calibration. The trabecular BMD in 111
postmenopausal American women (55 with fracture), and in 185 postmenopausal Japanese women (67 with fracture) were compared
for investigation of the difference in BMD values relative to fracture status. The absolute BMD values in Japanese were lower
than those in Americans, and the differences were greater with advancing age. The magnitude of the BMD difference was 8.6,
20.5, 38.1 mg/cm3 in women aged 20–24 years, 40–44 years, 60–64 years, respectively. In premenopausal women, BMD began to decrease at the age
of 20 in Japanese, whereas the peak bone mass was maintained until the age of 35 in the American women. In immediate postmenopausal
women, BMD significantly decreased in both populations. In later postmenopausal women, BMD significantly decreased with age
in the Japanese women but decreased less rapidly in the American women. The aging decrease of BMD was 1.4% and 2.2% per year
in the later postmenopausal American and Japanese women, respectively. The fracture threshold is considered to be lower in
Japanese women. However, the BMD difference between American and Japanese women with fracture was similar to that without
fracture. The Z-scores of fracture subjects versus controls were 2.9 in American and 1.8 in Japanese women. In conclusion,
Japanese women were found to have a lower BMD and lower fracture threshold than American women. The significant decrease of
spinal trabecular BMD in late postmenopause is potentially responsible for the higher prevalence of spinal fracture in Japanese
women.
Received: 18 December 1995 / Accepted: 23 September 1996 相似文献