首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   32576篇
  免费   1411篇
  国内免费   157篇
耳鼻咽喉   260篇
儿科学   551篇
妇产科学   316篇
基础医学   3862篇
口腔科学   881篇
临床医学   1928篇
内科学   7810篇
皮肤病学   472篇
神经病学   2646篇
特种医学   1501篇
外科学   5732篇
综合类   180篇
一般理论   1篇
预防医学   1092篇
眼科学   943篇
药学   2452篇
中国医学   96篇
肿瘤学   3421篇
  2023年   117篇
  2022年   263篇
  2021年   469篇
  2020年   289篇
  2019年   375篇
  2018年   478篇
  2017年   373篇
  2016年   500篇
  2015年   508篇
  2014年   651篇
  2013年   940篇
  2012年   1522篇
  2011年   1705篇
  2010年   938篇
  2009年   805篇
  2008年   1561篇
  2007年   1790篇
  2006年   1848篇
  2005年   1842篇
  2004年   1864篇
  2003年   1694篇
  2002年   1757篇
  2001年   1031篇
  2000年   1016篇
  1999年   921篇
  1998年   512篇
  1997年   419篇
  1996年   399篇
  1995年   300篇
  1994年   310篇
  1993年   258篇
  1992年   623篇
  1991年   586篇
  1990年   562篇
  1989年   537篇
  1988年   475篇
  1987年   464篇
  1986年   459篇
  1985年   443篇
  1984年   294篇
  1983年   230篇
  1982年   148篇
  1981年   131篇
  1980年   120篇
  1979年   210篇
  1978年   147篇
  1977年   131篇
  1975年   109篇
  1973年   109篇
  1970年   115篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
We report on a male patient with Pick disease who had shown severe white matter atrophy and dilatation of the lateral ventricle in the frontal lobe from an early stage. Upon admission to our hospital 2 years after disease onset, the patient showed apathy, and MRI revealed severe atrophy of the cortex and white matter of the frontal lobe. He died at age 74, 11 years after disease onset. Autopsy revealed severe atrophy of the frontal and temporal lobes, severe loss of white matter in the frontal lobe, dilatation of the lateral ventricles, and cortical thinning. Histopathological examination showed severe loss of myelinated fibers in the frontal white matter and severe neuronal loss with gliosis in the frontal and temporal cortices. Many Pick bodies were seen. Our patient had a rare case of Pick disease predominantly affecting the frontal lobe with severe involvement of the white matter from an early stage. This case suggests that myelinated fibers in the white matter as well as cerebral neurons are primarily affected in Pick disease.  相似文献   
52.
While there have been many reports of the significant role of cytoplasmic free calcium ion in myocardial injury, these have been carried out in multicellular preparations. Since cell injury may occur inhomogeneously, it is necessary to observe the 'history' of an individual myocyte in order to investigate the detailed role of the calcium ion in the process of myocardial injury. We have observed the natural history of individual myocytes isolated from the left ventricle of rats with respect to changes in shape and cytoplasmic free calcium concentration ([Ca2+]i) measured with fura-2. We can discriminate four phases in the time course of cell deterioration. In the first phase (phase O), the myocyte is rod shaped, quiescent and responsive to electrical stimulation. The [Ca2+]i is stable. In the next phase (Phase 1), once initiated, the myocyte exhibits an asynchronous wavy contraction and gradually decreases in length. The [Ca2+]i gradually increases with some fluctuation. Phase 2 is characterized by rapid development of contracture with a marked increase in [Ca2+]i. In the period following establishment of contracture (Phase 3), changes in [Ca2+]i vary from cell to cell, possibly because of leakage of the dye caused by loss of cell membrane integrity. Our results indicate that, during naturally occurring cell deterioration, loss of [Ca2+]i control at the membrane of the sarcoplasmic reticulum precedes contracture and catastrophic increase in [Ca2+]i.  相似文献   
53.
54.
When stimulating the mixed nerve to record evoked potential, both sensory and motor fibers are activated before entering the spinal cord. The N10 potential has been described as an antidromic motor evoked potential based on results obtained by recording at the anterior midneck. In the present study, we examined the changes in latencies of Erb's potential, N10, and N13 by stimulating the median nerve distally at the wrist and proximally at the elbow. The conduction velocity of N10 calculated by the difference between N10 latencies at the two stimulation points was consistent with motor conduction velocity, although N13 conduction velocity estimated by the same method reflected a sensory conduction velocity. A positive relation was also observed between the indirect latency from the stimulation point to the anterior root as calculated using the equation (F - M - 1) / 2 (ms) and the direct latency to the negative peak of the N10 potential. Our data support the notion that N10 represents antidromic motor potential originating in the spinal entry zone of the anterior root.  相似文献   
55.
Some chordomas have a very poor prognosis because of their aggressive growth nature, but the efficacy of repeat operations for these cases has not been well documented. This report concerns 3 patients with aggressive chordoma of the clivus, who underwent operations 6 to 12 times over a period of 8 to 17 years because of symptomatic regrowth. Overall mean interval between repeat operations was 18 months with a range from 5 to 57 months and survival times were 9 to19 years after the first surgery. Main symptoms before each operation were diplopia and visual disturbance. Repeat palliative operations by intentional extradural debulking of the tumour to decompress offending neural structures, as well as maximal removal of the tumour, using appropriate skull base approaches, can mitigate progressive symptoms, and may result in better quality and some prolongation of life, although our patients gradually deteriorated neurologically throughout the clinical course.  相似文献   
56.
A case of inflammatory pseudosarcoma of the urinary bladder in a 35 year-old Japanese male is presented. This benign lesion can easily be mistaken for spindle cell sarcoma since it consists of rhabdomyoblast like elongated strap cells showing infiltrative growth, and whether it is benign or malignant is difficult to determine by microscopic examination. In this case, spindle cell proliferation extended among bundles of the superficial muscle layer. However, no abnormal mitoses, severe nuclear atypia or cellular pleomorphism could be seen, thus indicating inflammatory pseudosarcoma. Although the lesion was not completely resected, no recurrent disease has been clinically observed for two years following transurethral resection. Urologists and surgical pathologists must be able to detect this lesion in order to avoid unnecessary surgical procedures. Acta Pathol Jpn 42: 760 765,1992.  相似文献   
57.
Here we report the finding of enzymatic activity that specifically cleaves DNA containing 8-hydroxyguanine (oh8Gua) residues in various mammalian cells. To detect this activity, we used a synthetic double-stranded DNA containing a single oh8Gua at a defined position as the substrate, and analyzed the products of enzymatic digestion by polyacrylamide gel electrophoresis. Two cleavage sites near the oh8Gua residue were detected with partially purified fractions from cow brain and rat liver, and also with preparations from all mammalian tissues examined. These results suggest that enzymatic activity for the removal of oh8Gua from DNA is widely distributed in mammalian cells.  相似文献   
58.
Tuberculous aneurysms of the aorta need early diagnosis and prompt surgical intervention because if untreated, they lead to severe consequences. We report herein, a case of a 63 year old woman who underwent successful resection of a tuberculous pseudoaneurysm which had ruptured into the left upper lobe of the lung after a punch biopsy, performed under bronchoscopy, had caused severe bleeding. Subsequent CT and MRI examinations suggested a fistula between the mass and the aorta and proved useful in establishing the diagnosis of a pseudoaneurysm. We wish to emphasize the need for bronchoscopy to be done carefully because of the risk of inducing massive hemoptysis.  相似文献   
59.
Summary The hepatic falciform ligament artery (HFLA) was evaluated by angiography and also by dissections. Based on the findings, the mechanism of the post-chemoembolization skin rash was studied. A total of 340 liver cirrhosis patients who underwent hepatic artery chemoembolization for hepatocellular carcinoma were reviewed in terms of the angiographic incidence of the HFLA, variations in its origin, and the incidence of skin rash. The HFLA was demonstrated in 26 (7.6%) of the 340 patients on angiography. Two HFLAs were observed in one patient. The origin was the middle hepatic artery (A4) in 16 cases, the superior branch of the middle hepatic artery in three, the inferior branch of the middle hepatic artery in two, the inferior branch of the left hepatic artery (A3) in three, and the confluence of A3 and A4 in three cases. There were no patients who developed post-chemoembolization skin rash. Two cadavers were dissected to investigate the anastomosis between the HFLA and the subcutaneous artery. Two different anastomoses were found: (1) direct and (2) via the ensiform branch of the internal thoracic artery. These were located at the lower and upper part of the falciform ligament, respectively. The distribution of a chemotherapeutic agent through these anastomoses is the likely cause of post-chemoembolization skin rash. If prophylactic embolization of the proximal portion of the HFLA using a metallic coil is performed, the skin rash will be prevented.
L'artère du ligament rond du foie : anatomie angiographique et implication clinique
Résumé L'artère du ligament falciforme hépatique (ALFH) fut étudiée par des angiographies et des dissections. D'après les résultats, le mécanisme d'un rash cutané après chimio-embolisation est discuté. Un total de 340 patients présentant une cirrhose hépatique ayant eu une chimio-embolisation de l'artère hépatique pour un carcinome hépato-cellulaire fut revu en fonction de l'incidence angiographie de l'ALFH, les variations d'origine de l'ALFH, et l'incidence d'un rash cutané. L'ALFH fut objectivée angiographiquement chez 26 (7,6%) des 340 patients. Deux ALFH furent objectivées chez un patient. L'origine des ALFH était située sur l'artère hépatique moyenne (A4) dans 16 cas, la branche supérieure de l'artère hépatique moyenne dans 3 cas, la branche inférieure de l'artère hépatique moyenne dans 2 cas, la branche inférieure de l'artère hépatique gauche (A3) dans 3 cas, et la confluence A3 et A4 dans 3 cas. Aucun patient ne développa un rash cutané après chimio-embolisation. Deux cadavres furent disséqués pour étudier les anastomoses entre l'ALFH et les artères sous-cutanées. Deux types d'anastomoses entre l'ALFH et des artères sous-cutanées furent individualisés directement et par l'intermédiaire de l'artère xiphoïde et de l'artère thoracique interne. Celles-ci étaient respectivement situées à la partie inférieure et à la partie supérieure du ligament falciforme. La distribution de l'agent chimiothérapique par ces anastomoses est vraisemblablement la cause des rash cutanés après chimio-embolisation. Dans le cas d'une embolisation prophylactique de la portion proximale de l'ALFH par utilisation d'un coil métallique le rash cutané pourrait être prévenu.
  相似文献   
60.
We report a 73-year-old woman with typical clinical, histological and immunofluorescence features of pemphigoid nodularis. Direct immunofluorescence studies of prurigo nodularis-like lesions and peribullous skin showed the linear deposition of IgG and C3 at the basement membrane zone. Circulating IgG against the basement membrane was also detected by indirect immunofluorescence. The serum from the patient was shown to contain the autoantibody against 230 kDa hemidesmosomal antigen associated with bullous pemphigoid antigen.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号