全文获取类型
收费全文 | 6070篇 |
免费 | 351篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 76篇 |
妇产科学 | 95篇 |
基础医学 | 782篇 |
口腔科学 | 164篇 |
临床医学 | 405篇 |
内科学 | 1815篇 |
皮肤病学 | 230篇 |
神经病学 | 278篇 |
特种医学 | 243篇 |
外科学 | 923篇 |
综合类 | 25篇 |
预防医学 | 258篇 |
眼科学 | 100篇 |
药学 | 338篇 |
中国医学 | 8篇 |
肿瘤学 | 688篇 |
出版年
2023年 | 64篇 |
2022年 | 107篇 |
2021年 | 181篇 |
2020年 | 86篇 |
2019年 | 108篇 |
2018年 | 154篇 |
2017年 | 117篇 |
2016年 | 134篇 |
2015年 | 131篇 |
2014年 | 184篇 |
2013年 | 235篇 |
2012年 | 376篇 |
2011年 | 371篇 |
2010年 | 203篇 |
2009年 | 173篇 |
2008年 | 312篇 |
2007年 | 308篇 |
2006年 | 299篇 |
2005年 | 323篇 |
2004年 | 263篇 |
2003年 | 280篇 |
2002年 | 317篇 |
2001年 | 132篇 |
2000年 | 144篇 |
1999年 | 122篇 |
1998年 | 73篇 |
1997年 | 72篇 |
1996年 | 51篇 |
1995年 | 43篇 |
1994年 | 37篇 |
1993年 | 36篇 |
1992年 | 88篇 |
1991年 | 86篇 |
1990年 | 81篇 |
1989年 | 67篇 |
1988年 | 73篇 |
1987年 | 54篇 |
1986年 | 55篇 |
1985年 | 43篇 |
1984年 | 36篇 |
1983年 | 45篇 |
1982年 | 23篇 |
1979年 | 29篇 |
1974年 | 35篇 |
1973年 | 32篇 |
1972年 | 23篇 |
1971年 | 34篇 |
1970年 | 34篇 |
1969年 | 27篇 |
1967年 | 21篇 |
排序方式: 共有6463条查询结果,搜索用时 15 毫秒
1.
2.
Kentaro Yamasaki Takafumi Ishida Tatsuya Kishino Norio Niikawa 《American journal of medical genetics. Part A》2002,111(3):301-306
We report on a Thai family with dominantly inherited malformation syndrome with upper limb anomalies, short stature, quadricuspid aortic valve, and minor craniofacial anomalies. The affected individuals comprised a mildly affected mother, a moderately affected daughter, and a most severely affected son. The daughter and son had short stature. The craniofacial abnormalities comprised frontal bossing, hypoplastic nasal bones, depressed nasal bridge, and broad nasal alae. The upper limb defects varies among the patients, ranging from radial ray defects in the mother through radial and ulnar ray defects with unilateral humeral hypoplasia in the daughter to radial ray defects with severe oligodactyly and bilateral humeral hypoplasia in the son. All patients in this family had hypoplasia of the shoulder girdle and resembled what is observed in many families with Holt‐Oram syndrome. Moreover, the son showed quadricuspid aortic valve with mild aortic regurgitation. However, the present family did not show any mutation of the TBX5 gene, a disease‐causing gene of Holt‐Oram syndrome. The present family deserves further investigation on other genes that play a role in the development of the upper limbs, particularly of radial rays. © 2002 Wiley‐Liss, Inc. 相似文献
3.
Neurotoxic effects of flunarizine (Fz), a selective calcium channel blocker, on the nigrostriatal dopamine system was investigated. Systemic injections of Fz to mice resulted in a transient loss of tyrosine hydroxylase (TH) immunoreactive nigrostriatal neurons without cell loss. TH immunoreactivity in these neurons was greatly reduced as rapidly as one day after drug administration (regardless of dosage used) and thereafter recovered in both dose- and time-dependent manners. Such a novel neurotoxic action of Fz may constitute a morphological substrate for reversible drug-induced parkinsonian signs described in recent clinical case reports. 相似文献
4.
H Hirai K Yamasaki H Kidena M Kono 《Kaku igaku. The Japanese journal of nuclear medicine》1992,29(12):1447-1454
In vivo sodium concentrations in the normal brain tissue and a tumorous tissue were analyzed using MR Na image. The nuclear magnetic resonance enabled us to divide the signal from sodium in the living tissue into 2 parts based on the differences of T2 value. Those are fast component having the T2 value of less than 5 msec and slow component of 15-40 msec. We investigated the effect of macromolecules on T2 value of sodium image using polyvinyl alcohol (PVA) powder. MR Na image was taken with the parameters of TR/TD, 110 ms/1.9 ms (FID image) and TR/TE, 110 ms/20 ms (SE image). Saline solution showed high intensity on both FID image and SE image. Saline solution added PVA (PVA phantom) also showed high intensity on FID image, whereas the signal intensity of PVA phantom in SE image extinguished. To know the relation between the signal intensity and sodium concentration, sodium concentration--signal intensity curve was obtained using phantoms with various sodium concentrations (0.05-1.0%). This curve showed a direct proportion between sodium concentration and signal intensity on Na image. We measured further the sodium concentrations of the human brain tissue. Sodium phantoms were arranged around the heads and the MR Na images of the normal brains from 3 volunteers and a patient with a brain tumor (meningioma) were taken. The sodium concentrations of occipital lobe, basal ganglia and the tumorous tissue were calculated using the sodium concentration--signal intensity curve obtained from the phantoms arranged around the heads.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
5.
Shigeru Onodera Koji Saito Takafumi Saito Hitoshi Togashi Sumio Kawata Katsuaki Ukai Haruhide Shinzawa 《Nihon Shokakibyo Gakkai zasshi》2007,104(2):213-218
It is well known that long-term infection with Clonorchis sinensis often causes bile duct cancer, usually. It occurs in the intrahepatic bile duct. We encountered a rare case of clonorchiasis complicated with duodenal papillary cancer. The patient was a woman from China. Although clonorchiasis is rarely found in Japan, the promotion of international exchange may increase the number of visitors from endemic areas. Thus we must pay sufficient attention to this disease. Also, we reported that the microplate ELISA technique was useful in the diagnosis of clonorchiasis with high accuracy in this case. 相似文献
6.
OBJECTIVE: The purpose of this study was to characterize the etching behavior of titanium in concentrated sulfuric acid and discuss its application on surface modification of titanium for biological use. METHODS: Commercially pure titanium (cpTi) plate was etched in 48% H2SO4 at RT -90 degrees C for 0.25-8 h. The weight loss was derived from the weight differences before and after etching. The surfaces after etching were characterized by surface roughness, X-ray diffractometry, and scannning electron spectroscopy. The apparent activation energy of the dissolution of cpTi into acid was derived from an Arrhenius plot of the rate of weight loss versus the acid temperature. RESULTS: The surface roughness of cpTi increased with the acid temperature and etching time. The surface roughness was strongly related to the weight loss. The weight loss increased drastically with the acid temperature after an initial period, which shortened with increasing acid temperature. The apparent activation energy for the dissolution of cpTi in H2SO4 was derived as 67.8 kJ/mol. SIGNIFICANCE: This study indicates that etching with concentrated sulfuric acid is an effective way to modify the surface of titanium for biological applications. 相似文献
7.
The purpose of this study was to determine the effect of pulsatile flow on cerebral perfusion under cardiopulmonary bypass (CPB). Twenty-three patients who underwent cardiac operations were divided into two comparable groups: Group A (N = 11) had standard nonpulsatile flow, while in Group B (N = 12), a pulsatile pump was used. The blood flow of left common carotid artery and radial arterial pressure were continuously monitored during cardiac operation in both groups and cerebral vascular resistance was calculated. In Group B, the perfusion pressure of left common carotid artery was monitored and compared with that of radial artery. Arterial and internal jugular venous blood were sampled and the difference of cerebral A.V O2 contents and cerebral oxygen consumption was calculated. Cerebral vascular resistance in Group B (54.0 +/- 11.2% of the value of before-CPB) significantly decreased compared to that in Group A (72.2 +/- 11%) at the end of CPB (p less than 0.05). Pulse pressure following pulsatile CPB flow was 15.1 +/- 5.8 mmHg monitored in radial artery and it reduced to 8.5 +/- 5 mmHg in left common carotid artery. Although there was no significant difference in cerebral oxygen consumption of both groups during and just after CPB, the difference of cerebral A-V O2 contents of Group B was greater than Group A just after CPB. These data suggest that pulsatile flow may minimize the cerebral microcirculatory shunt during CPB, resulting from the reduction of cerebral vascular resistance. 相似文献
8.
9.
Yukata Okita M.D. Shigehito Miki M.D. Yuichi Ueda M.D. Takafumi Tahata M.D. Tetsuro Sakai M.D. Katsuhiko Matsuyama M.D. Masahiko Matsumura M.D. 《Journal of cardiac surgery》1994,9(4):433-439
A 6-year-old boy was successfully operated on for double outlet ventricle, common atrioventricular canal with severe valvular regurgitation, right atrial Isomerism, L-loop ventricles, total anomalous pulmonary venous connection, and pulmonary stenosis with hypoplastic left pulmonary artery. The Interventricular rerouting from the left ventricle to the ascending aorta was performed with a spiral patch, the lnteratrlal switching was performed by a Mustard patch, the common atrioventricular orifice was partitioned and valve repair was performed, and an 18-mm valved conduit was inserted between the right ventricle and the pulmonary artery. Although the patient had a small residual ventricular septal defect and pulmonary stenosls, the patient Is alive and well. 相似文献
10.
Differential expression of the beta I- and beta II-PKC subspecies in the postnatal developing rat brain; an immunocytochemical study. 总被引:1,自引:0,他引:1
Differential expression of protein kinase C subspecies, beta I- and beta II-PKC, derived from a single gene by alternative splicing was evidenced in the postnatal developing rat brain. Immunoblot analysis of the PKC subspecies in the whole developing brain showed that beta I-PKC was present at birth and then gradually increased, while beta II-PKC was not present at birth or on postnatal day 3, then increased rapidly from day 7 to the maximum value seen in the adult brain. Under light microscopy, beta I-PKC immunoreactivities seen at birth were the most intense in the brainstem and intense in the diagonal bundle and globus pallidus. beta I-PKC immunoreactivities in these neurons weakened from day 7 and disappeared in the adult brain, while in the cerebral cortex, triangular septal nucleus and pontine nucleus beta I-PKC immunoreactivities were week at birth and then gradually increased. beta II-PKC immunoreactivities were first visible in neurons on day 7 and increased progressively. beta I- and beta II-PKCs were not co-localized in a neuron, as far as examined. The immunoreactivities of beta I-PKC at birth were localized in growth cone-like structures as well as in the dendrites and perikarya. Similarly, alpha-PKC was also present at birth in the growth cone-like structure. Immunoblot analysis revealed that beta I-PKC was present at birth in the growth cone-rich fraction from the hindbrain but not in that from the forebrain, while alpha-PKC was found in the growth cone-rich fraction from both the forebrain and the hindbrain. beta II- and gamma-PKC were not detected in the growth cone-rich fraction from either forebrain or hindbrain. These findings suggest that beta I- and beta II-PKC play a role in different stages of development and in different neurons; both beta-subspecies may be involved in postnatal developing neuronal functions while only beta I-PKC plays functional roles in the growth cone, in the prenatal developmental stage. 相似文献