全文获取类型
收费全文 | 51379篇 |
免费 | 2447篇 |
国内免费 | 268篇 |
专业分类
耳鼻咽喉 | 748篇 |
儿科学 | 949篇 |
妇产科学 | 887篇 |
基础医学 | 6648篇 |
口腔科学 | 1387篇 |
临床医学 | 3445篇 |
内科学 | 12310篇 |
皮肤病学 | 994篇 |
神经病学 | 4149篇 |
特种医学 | 1987篇 |
外科学 | 9137篇 |
综合类 | 230篇 |
一般理论 | 4篇 |
预防医学 | 1686篇 |
眼科学 | 797篇 |
药学 | 3923篇 |
中国医学 | 100篇 |
肿瘤学 | 4713篇 |
出版年
2023年 | 243篇 |
2022年 | 506篇 |
2021年 | 904篇 |
2020年 | 494篇 |
2019年 | 646篇 |
2018年 | 799篇 |
2017年 | 653篇 |
2016年 | 817篇 |
2015年 | 860篇 |
2014年 | 1132篇 |
2013年 | 1462篇 |
2012年 | 2256篇 |
2011年 | 2484篇 |
2010年 | 1487篇 |
2009年 | 1267篇 |
2008年 | 2400篇 |
2007年 | 2579篇 |
2006年 | 2517篇 |
2005年 | 2528篇 |
2004年 | 2408篇 |
2003年 | 2419篇 |
2002年 | 2438篇 |
2001年 | 1718篇 |
2000年 | 1852篇 |
1999年 | 1631篇 |
1998年 | 678篇 |
1997年 | 545篇 |
1996年 | 530篇 |
1995年 | 439篇 |
1994年 | 396篇 |
1993年 | 351篇 |
1992年 | 1184篇 |
1991年 | 993篇 |
1990年 | 974篇 |
1989年 | 994篇 |
1988年 | 879篇 |
1987年 | 871篇 |
1986年 | 819篇 |
1985年 | 801篇 |
1984年 | 563篇 |
1983年 | 447篇 |
1982年 | 246篇 |
1980年 | 218篇 |
1979年 | 495篇 |
1978年 | 287篇 |
1977年 | 264篇 |
1974年 | 230篇 |
1971年 | 240篇 |
1969年 | 235篇 |
1968年 | 216篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Effects of smoking and drinking on excretion of hippuric acid among toluene-exposed workers 总被引:1,自引:1,他引:0
Osamu Inoue Kazunori Seiji Takao Watanabe Haruo Nakatsuka Chui Jin Shi-Jie Liu Masayuki Ikeda 《International archives of occupational and environmental health》1993,64(6):425-430
Summary In order to investigate possible effects of smoking and drinking on the metabolism of toluence in occupational settings, 206 toluene-exposed men (mean age: 31.4 years) in shoemaking, painting, or surface-coating workshops together with 246 nonexposed control men (36.8 years) were studied for the time-weighted average intensities of exposure to toluene, hippuric acid concentration in shift-end urine samples, and the two social habits of smoking and drinking. The mean daily consumptions of cigarettes and ethanol were about 20 pieces and 10 g among smokers and drinkers, respectively. The geometric mean toluene concentration among the exposed subjects was about 20 ppm, with a maximum of 521 ppm. Regression analysis after classification of the subjects by smoking and drinking clearly demonstrated that the two social habits, when combined, markedly reduce the hippuric acid level in the urine of workers exposed to was a significant association between smoking and drinking habits, which hindered separate evaluation of the effects of the two habits on toluene metabolism. Comparison of the present results with the findings reported in the literature, however, suggested that the observed effects may be attributable to smoking rather than to drinking habits. 相似文献
82.
Two cases of subcortical hemorrhage with asymptomatic occlusion of the main trunk of cerebral artery
We report two cases of asymptomatic occlusion of the main trunk of the cerebral artery associated with subcortical hemorrhage in the area fed by collateral circulation. The first patient, a 51-year-old female who had suffered from untreated hypertension for 20 years, was hospitalized in a state of coma. Computed tomography (CT) revealed a subcortical hemorrhage in the right parietal lobe as well as subdural and subarachnoid hemorrhages. Cerebral angiography disclosed occlusion of the right internal carotid artery at its origin. The region normally supplied by the right anterior (ACA) and middle cerebral (MCA) arteries was supplied instead by the posterior cerebral artery via leptomeningeal anastomosis. The hematoma was removed and the patient was discharged 1 month later. The second patient was a 54-year-old female who had suffered from uncontrollable hypertension for 27 years and was hospitalized after sudden development of stupor, right hemiparesis and motor aphasia. CT demonstrated a subcortical hemorrhage in the left parietal lobe. Cerebral angiography disclosed occlusion of the left MCA at its origin. The area normally fed by the left MCA was supplied instead by the ACA by way of leptomeningeal anastomosis. One month after operation the patient was transferred to another hospital for rehabilitation of right hemiparesis. Both of these middle-aged women had long-standing hypertension. The hemorrhages were thought to result from rupture of the leptomeningeal anastomosis, which had developed as collateral vessels. It is probable that the relatively weak leptomeningeal anastomosis could no longer withstand the increased blood flow brought on by the hypertension. 相似文献
83.
Changes in the levels of urea cycle enzymes and polyamine metabolism in the liver of rats treated with alpha-naphthylisothiocyanate (ANIT), an inducer of experimental cholestasis, were studied. Activities of arginase increased approximately two-fold compared to the control values during the period of 24-72 hours after oral administration of ANIT (100 mg/kg), while activities of ornithine carbamyltransferase and ornithine aminotransferase decreased. The activity of ornithine decarboxylase was elevated by approximately 20- and 10-fold at 12 and 60 hours, respectively, after ANIT administration. Putrescine concentration doubled 24-48 hours after the ANIT administration, but spermidine level rose more slowly and reached the level of 1.5-fold of the control level in 36-72 hours. Spermine concentration decreased initially but increased in 96 hours. These results suggest that the increased activity of urea cycle accounts for the increase in the ornithine content and that the putrescine and spermidine acts as the initiator of recovery of the liver damaged by ANIT treatment. 相似文献
84.
Osamu Yokota Kuniaki Tsuchiya Yoshimasa Noguchi Hisamasa Akabane Hideki Ishizu Yukinobu Saito Haruhiko Akiyama 《Neuropathology》2007,27(6):539-550
We report a case of a 68‐year‐old right‐handed man with sporadic amyotrophic lateral sclerosis (ALS) and argyrophilic grain disease (AGD) having a 22‐month duration. His initial symptoms were dysarthria and swallowing difficulty at the age of 67. Subsequently bulbar palsy and pyramidal signs developed. His cognitive functions including face recognition, personality, and behavior were not changed compared with that of before the disease onset. However, magnetic resonance imaging disclosed severe right side‐predominant temporal atrophy. The neurological diagnosis was bulbar type ALS. Pathological examination disclosed histological evidence of ALS, including loss of Betz cells and lower motor neurons, corticospinal tract degeneration, and Bunina bodies. In addition, severe neuronal loss in the bilateral temporal cortex with an anterior gradient was found. Ubiquitin‐positive inclusions were encountered in the spinal anterior horn cells and hippocampal dentate gyrus, while few ubiquitin‐positive inclusions were noted in the affected temporal cortex. The amygdala, especially the basolateral nuclear group, was severely affected by neuronal loss with tissue rarefaction. Moderate neuronal loss was encountered in the parahippocampal gyrus, and to a lesser degree, in the ambient gyrus. Unexpectedly, many argyrophilic grains, coiled bodies, tau‐positive bush‐like astrocytes, pretangles, and ballooned neurons were found in the limbic system and temporal cortex. In the hippocampus, selective tau accumulation with minor neurofibrillary changes was observed in CA2 neurons. The present case suggests that (i) ALS and AGD do rarely coexist, and (ii) when ALS patients have severe temporal atrophy, not only ALS with dementia but also concurrent AGD should be considered in the differential diagnosis. 相似文献
85.
86.
87.
Y Aso Y Ohtawara K Fukuta H Sudoko M Nakano T Ushiyama N Ohta K Suzuki A Tajima 《The Journal of urology》1987,137(4):629-632
We tested 2 prototypes of an operating fiberoptic nephroureteroscope, measuring 3.5 and 4.5 mm. in diameter, that have an adequate working channel for auxiliary instruments and irrigation. Difficulty in passing the fiberscope through the ureteral orifice was overcome by dilation with balloon and polytetrafluoroethylene (Teflon) dilators. Our initial trial for stone retrieval under fiberscopic control was performed on 21 patients with upper ureteral and renal calculi. A stone was removed successfully in 15 of the 21 patients (71 per cent). After electrohydraulic lithotripsy calculi were extracted successfully in 9 of 11 patients (82 per cent). Three patients suffered ureteral perforation. The fiberscope was especially helpful when an upper ureteral stone moved back to the kidney during stone manipulation. 相似文献
88.
J Kusakari K Hozawa T Hanazima S Suzuki T Takasaka N Sasano 《Archives of oto-rhino-laryngology》1987,244(4):246-248
We report a case of cylindrical cell papilloma of the paranasal sinuses. This tumor originated in the medial wall of the left maxillary sinus of a 69-year-old man and extended to the surrounding tissues. Pathological study of tissue sections from the tumor showed typical findings of cylindrical cell papilloma with no evidence of associated malignancy. Histochemical and electron microscopic examinations revealed a large number of mitochondria in the cytoplasm of the tumor cells. The tumor was removed through a Denker's approach. The patient did well following surgery and there has been no sign of recurrence in a 2-year follow-up study. 相似文献
89.
Masayoshi Tachibana Norio Yasuda Masaki Yoshimatsu Hideo Nishimura Osamu Mizukoshi 《Cancer chemotherapy and pharmacology》1987,19(1):65-68
Summary UFT, a combination of the masked compound of 5-fluorouracil (FT-207) and uracil, was given to head and neck cancer patients for 1 week preoperatively and for 8 weeks postoperatively. Drug concentrations were examined in the surgically removed tissues. The concentrations of FT-207, 5-fluorouracil, and uracil were higher in tumor tissues than in normal tissues. The lymphocyte subpopulations were assessed by cytofluorometry with monoclonal antibodies. There was no evidence that adjuvant chemotherapy with UFT specifically suppresses immunocompetent cells. We therefore conclude that further clinical evaluation of adjuvant chemotherapy with UFT would be worthwhile. 相似文献
90.