全文获取类型
收费全文 | 12971篇 |
免费 | 593篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 139篇 |
儿科学 | 202篇 |
妇产科学 | 294篇 |
基础医学 | 1497篇 |
口腔科学 | 296篇 |
临床医学 | 854篇 |
内科学 | 3459篇 |
皮肤病学 | 190篇 |
神经病学 | 844篇 |
特种医学 | 326篇 |
外科学 | 2459篇 |
综合类 | 33篇 |
预防医学 | 421篇 |
眼科学 | 218篇 |
药学 | 1280篇 |
中国医学 | 12篇 |
肿瘤学 | 1100篇 |
出版年
2023年 | 76篇 |
2022年 | 182篇 |
2021年 | 277篇 |
2020年 | 138篇 |
2019年 | 196篇 |
2018年 | 214篇 |
2017年 | 166篇 |
2016年 | 227篇 |
2015年 | 219篇 |
2014年 | 286篇 |
2013年 | 364篇 |
2012年 | 561篇 |
2011年 | 618篇 |
2010年 | 319篇 |
2009年 | 294篇 |
2008年 | 521篇 |
2007年 | 545篇 |
2006年 | 523篇 |
2005年 | 526篇 |
2004年 | 541篇 |
2003年 | 523篇 |
2002年 | 523篇 |
2001年 | 448篇 |
2000年 | 436篇 |
1999年 | 391篇 |
1998年 | 147篇 |
1997年 | 97篇 |
1996年 | 83篇 |
1995年 | 71篇 |
1994年 | 71篇 |
1993年 | 68篇 |
1992年 | 350篇 |
1991年 | 299篇 |
1990年 | 300篇 |
1989年 | 314篇 |
1988年 | 302篇 |
1987年 | 295篇 |
1986年 | 260篇 |
1985年 | 211篇 |
1984年 | 181篇 |
1983年 | 150篇 |
1982年 | 80篇 |
1979年 | 154篇 |
1978年 | 82篇 |
1977年 | 73篇 |
1975年 | 84篇 |
1973年 | 68篇 |
1972年 | 75篇 |
1971年 | 85篇 |
1969年 | 76篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
K Takeuchi S Suzuki N Kako M Kobayashi S Takahashi M Sawada T Honma S Iwabuchi K Fukui K Koyama 《The Annals of thoracic surgery》1992,54(2):327-332
The mechanism by which prostacyclin acts to prevent in vivo reperfusion injury is still uncertain. This study was therefore undertaken to assess the effect of a stable prostacyclin analogue (OP 41483-alpha-CD [OP]) on oxygen-derived free radicals after heart-lung transplantation. OP was administered to the heart-lung graft through the pulmonary artery for 25 minutes encompassing the reperfusion process. Free radicals were directly measured by electron spin resonance spectroscopy. The radical intensities of pulmonary venous blood were significantly lower in the OP group than in the control group, suggesting that fewer free radicals were generated in the lungs of the OP group. The cardiac and respiratory function were better in the OP group than in the control group. The lung is the primary source of oxygen free radical attack, and the beneficial action of OP on free radical generation is almost exclusively restricted to the lung and does not apply to the heart. This result suggested that OP probably is effective in inhibiting free radical generation from the endothelium. 相似文献
72.
S J Liu Q S Qu X P Xu Y T Liu S N Yin Y Takeuchi T Watanabe O Inoue M Yoshida M Ikeda 《American journal of industrial medicine》1992,22(3):313-323
A factory survey was conducted in three provinces in China from 1985 to 1989. The time-weighted average toluene concentrations in breathing zone air were monitored by diffusive sampling, whereas hippuric acid (HA) concentrations in shift-end urine samples were measured by high performance liquid chromatography (HPLC). Exposed workers (456 men and women) were those for whom toluene (up to 548 ppm toluene) accounted for greater than or equal to 90% of total exposure (by vapor concentration in ppm), whereas 517 nonexposed controls were recruited from the same factories or from factories of the same region. There was a linear correlation between the intensity of toluene exposure and HA concentration in the shift-end urine. Comparison of the results with findings in the literature shows that the toluene-induced increase in urinary HA concentration among workers in China is significantly smaller than the published values, whereas HA concentrations in urine samples from nonexposed controls are comparable to the levels previously reported. 相似文献
73.
Kawashima Yoshiaki Cui Fude Takeuchi Hirofumi Niwa Toshiyuki Hino Tomoaki Kiuchi Katsumi 《Pharmaceutical research》1995,12(7):1040-1044
Purpose. Poorly compressible crystals of acebutolol hydrochloride were agglomerated by the spherical crystallization technique with a two-solvent system to improve the compressibility for direct tabletting. The mechanism of improvements in static compression behaviors and tablettabilities of the spherically agglomerated crystals were investigated.
Methods. The improvement of static compression behaviors of the agglomerated crystals was determined by measuring the stress relaxations and elastic recoveries of compressed powder of original and agglomerated crystals. The improved tablettability of agglomerated crystals was evaluated by the pressure transmission ratio upon compression, the ejection pressure for releasing the tablet from the die and the tablet strength, i.e., tensile strength required for breaking.
Results. The higher relaxation pressure and the lower elastic recovery of the agglomerated crystals than of the original crystals were found. The pressure transmission ratio data showed that the friction pressures of the two crystals were similar during the compression period. The ejection pressure of the agglomerated crystals was lower than that of the original crystals. The tensile strength of the tablet of agglomerated crystals was greater than that of the original crystals.
Conclusions. The compressibility and tablettability of the spherically agglomerated crystals prepared by the spherical crystallization technique were much improved due to their increased plastic property and reduced adhesive property compared to the original crystals. 相似文献
74.
75.
Newborn infant with maternal anti-SSA antibody-induced complete heart block accompanying cardiomyopathy. 总被引:2,自引:0,他引:2
Newborn case of maternal anti-SSA antibody-induced congenital complete heart block (CCHB) accompanying cardiomyopathy is presented. Unexpectedly, she died of ventricular tachycardia, not bradycardia, 6 days after birth. Autopsy revealed left ventricular cardiomyopathy with endocardial fibroelastosis. Thus, when evaluating fetal cardiac performance in cases of maternal anti-SSA antibody-induced CCHB, it is necessary to pay attention to myocardial attributes such as endocardial hyperplasia. 相似文献
76.
Low doses of the Gn-RH agonist (buserelin, 30 micrograms) were given intranasally to 14 women with clomiphene ineffective hypothalamic amenorrhea three times daily for three weeks in order to study pituitary responses and to induce follicular maturation and ovulation. Clomiphene ineffective hypothalamic amenorrhea patients were classified into two groups by LH-RH stimulation test before the treatment. Group 1 was defined as having basal serum LH and FSH levels lower than 1.5 mIU/ml, LH and FSH peaks lower than 3mIU/ml by LH-RH stimulation test. Group 2 consisted of cases other than those in Group 1. While a significant increase in basal LH and FSH (p less than 0.01, p less than 0.001) and improvement in pituitary response to LH-RH stimulation test were observed in group 1, the basal levels of LH and FSH did not increase significantly and pituitary response to a LH-RH stimulation test was decreased in group 2. It is suggested that pituitary priming occurred in group 1 and pituitary desensitization occurred in group 2. None of 14 patients showed signs of follicular maturation during or after the treatment. The results demonstrated that the biphasic pituitary response to intranasal buserelin spray and the limit of its therapeutic use for the treatment of hypothalamic amenorrhea. 相似文献
77.
We report a 10-year-old Down syndrome patient who developed dystonia, choreoathetosis, dysarthria, and dysphagia beginning with hemiparesis. Cranial computed tomography disclosed bilateral calcification in the globus pallidus which resembled a sign of premature aging. Conversely, the clinical course and magnetic resonance imaging findings resembled those of Hallervorden-Spatz syndrome. 相似文献
78.
Cysts and tumors of the seminal vesicle are uncommon, and their coexistence is extremely rare. We report a case of multiple papillary tumors inside a seminal vesicle cyst associated with ipsilateral renal agenesis in a 17-year-old man. Surgical excision of the cyst and tumors was performed without any morbidity and histology revealed well differentiated papillary adenocarcinoma. 相似文献
79.
Summary Changes occurring in serotonin neurons during hyperthermia-induced convulsions were examined by means of a modified immunohistochemical method. All mice (8–12 weeks of age) exposed to the temperature of 50°C had convulsions, showing a generalized tonic and/or clonic pattern. Immediately after the convulsions, the animals were perfused transcardially with a fixative. A significant reduction in serotonin immunoreactivity was observed in the neostratum (caudate-putamen complex) of the mice which had hyperthermia-induced seizures, while the serotonin immunoreactivity remained unchanged in the neocortex and paleostriatum. These results suggest that serotonin may be an important mediator in the mechanism of hyperthermia-induced convulsions or that the susceptibility of serotonin neurons to a convulsive state is greatest in the neostriatum.Supported in part by Grant No. 86-05 from the National Center for Nervous, Mental and Muscular Disorders (NCNMMD) of the Ministry of Health and Welfare and Grant No. 62770677 from the Ministry of Education, Science and Culture, Japan 相似文献
80.
Takeshi Miyairi Shinichi Takamoto Yutaka Kotsuka Atsuko Takeuchi Katsuo Yamanaka Hajime Sato 《European journal of cardio-thoracic surgery》2005,28(1):97-101; discussion 102-3
OBJECTIVE: Retrograde cerebral perfusion (RCP) is used as an adjunctive method to hypothermic circulatory arrest to enhance cerebral protection in patients undergoing thoracic aortic surgery. It remains unclear whether RCP provides improved neurological and neuropsychological outcome. METHODS: Forty-six patients undergoing thoracic aortic surgery using RCP, and 28 undergoing coronary artery bypass grafting (CABG; n = 28) with CPB, were enrolled in the study. Patients receiving RCP were subdivided into two groups, those with less than 60 min of RCP (S-RCP; n = 27) and with 60 min or more (L-RCP; n = 19). The patients' neurocognitive state was assessed by the revised Wechsler Adult Intelligence Scale a few days before operation, at 2-3 weeks and 4-6 months after operation. RESULTS: There were no stroke, seizure, and hospital mortality in either group. Significant decline between baseline and early scores were seen in three subtests (digit span, arithmetic, and picture completion) for S-RCP and four (digit span, arithmetic, picture completion, and picture arrangement) for L-RCP. Significant decline between baseline and late scores were seen in one subtest (arithmetic) for S-RCP, four (digit span, arithmetic, picture completion, and picture arrangement) for L-RCP, and one (object assembly) for CABG. The mean change of scores for one late test (digit symbol) was significantly lower in S-RCP than in CABG. The mean change of scores for three early tests (digit span, vocabulary, and picture arrangement) and four late tests (information, digit span, picture completion, and picture arrangement) were significantly lower in L-RCP than in CABG. Stepwise logistic regression analysis disclosed that, after considering the other variables, significant difference in test score changes were observed between CABG and L-RCP for two early tests (picture completion and digit symbol) as well as for three late tests (digit span, similarities, and picture completion). None of test score changes showed significant difference between CABG and S-RCP. CONCLUSIONS: The neurocognitive outcome in patients undergoing RCP less than 60 min were comparable with patients undergoing CABG without circulatory arrest. Prolonged RCP of 60 min or more in patients undergoing surgery of the thoracic aorta was associated with postoperative neurocognitive impairment. 相似文献