全文获取类型
收费全文 | 12930篇 |
免费 | 582篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 145篇 |
儿科学 | 144篇 |
妇产科学 | 140篇 |
基础医学 | 1676篇 |
口腔科学 | 270篇 |
临床医学 | 772篇 |
内科学 | 2981篇 |
皮肤病学 | 205篇 |
神经病学 | 981篇 |
特种医学 | 497篇 |
外科学 | 2541篇 |
综合类 | 50篇 |
一般理论 | 1篇 |
预防医学 | 559篇 |
眼科学 | 186篇 |
药学 | 971篇 |
中国医学 | 40篇 |
肿瘤学 | 1410篇 |
出版年
2022年 | 114篇 |
2021年 | 239篇 |
2020年 | 120篇 |
2019年 | 178篇 |
2018年 | 209篇 |
2017年 | 180篇 |
2016年 | 226篇 |
2015年 | 202篇 |
2014年 | 261篇 |
2013年 | 392篇 |
2012年 | 545篇 |
2011年 | 621篇 |
2010年 | 339篇 |
2009年 | 319篇 |
2008年 | 486篇 |
2007年 | 589篇 |
2006年 | 580篇 |
2005年 | 569篇 |
2004年 | 587篇 |
2003年 | 536篇 |
2002年 | 585篇 |
2001年 | 439篇 |
2000年 | 468篇 |
1999年 | 425篇 |
1998年 | 177篇 |
1997年 | 146篇 |
1996年 | 122篇 |
1995年 | 95篇 |
1994年 | 93篇 |
1993年 | 91篇 |
1992年 | 359篇 |
1991年 | 318篇 |
1990年 | 323篇 |
1989年 | 298篇 |
1988年 | 286篇 |
1987年 | 287篇 |
1986年 | 278篇 |
1985年 | 216篇 |
1984年 | 151篇 |
1983年 | 144篇 |
1982年 | 56篇 |
1981年 | 57篇 |
1979年 | 115篇 |
1978年 | 58篇 |
1977年 | 57篇 |
1976年 | 48篇 |
1974年 | 51篇 |
1973年 | 61篇 |
1972年 | 65篇 |
1970年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
991.
It is known that pentobarbital, which has been used for severe brain infarct or head injury as a brain protective drug, inhibits the increase of free fatty acids (FFAs) liberated from membrane phospholipids during ischemia. However, the mechanisms of FFA liberation from phospholipids and the mode of action of pentobarbital are still unclear. Therefore we have investigated the effects of induction of global ischemia and pentobarbital pretreatment upon lipid metabolism in rat brain. Brain ischemia was evoked by rat decapitation and pentobarbital (60 mg/kg) was administered i.p. for 15 min prior to decapitation. Removed brains were incubated for 1, 5, 15 or 30 min at 37 degrees C and then quickly frozen in liquid nitrogen. After extraction of lipids from the brains, neutral lipid and phospholipid compositions were analyzed by thin-layer and gas-liquid chromatography. The results demonstrated that FFAs, either unsaturated or saturated, were rapidly accumulated in the brain during early period of ischemia, but attenuated significantly by pentobarbital pretreatment. Pentobarbital attenuated the accumulations of stearic and arachidonic acids, with little effect on palmitic and oleic acids. Diacylglycerol (DG), which is considered to be as a plausible candidate for the source of FFA, was also produced in the ischemic brain, and its acyl chain composition was similar to that of liberated FFAs. Furthermore, the increase of DG was inhibited significantly by pentobarbital anesthesia. In particular, pentobarbital attenuated the accumulation of DG enriched in arachidonic and stearic acids. This fatty acyl composition resembled the principal composition of phosphatidylinositol (PI) in rat brain.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
992.
993.
T Kawamoto T Hobara H Kobayashi E Higashihara S Iwamoto T Sato T Sakai 《Sangyō igaku. Japanese journal of industrial health》1986,28(4):260-265
Numerous reports have been published in the field of industrial health on biological monitoring of trichloroethylene exposure, but these studies have been confined to healthy humans. Trichloroethylene metabolism in individuals with chronic liver diseases has not been clarified. This experiment was therefore performed on rats that were administrated carbon tetrachloride subcutaneously for three months to induce chronic liver damage. The metabolism of trichloroethylene and its metabolites, chloral hydrate and trichloroethanol, were investigated using the isolated liver perfusion method. Comparing the changes of these substances in the chronically damaged liver with those in the intact liver, the following results were observed in the chronically damaged liver: The conversion of trichloroethylene to trichloroethanol and trichloroacetic acid decreased. The reduction of chloral hydrate to trichloroethanol increased. The oxidation of chloral hydrate to trichloroacetic acid decreased. The biliary excretion of trichloroethanol and trichloroacetic acid decreased. 相似文献
994.
T Andoh N Sakai H Yamada T Iwama Y Nishimura K Shimizu T Hirata A Ohkuma A Saitoh 《No shinkei geka. Neurological surgery》1991,19(4):327-336
Fusiform aneurysms (FA) and dissecting aneurysms (DA) of the vertebro-basilar systems have been thought to be rare, but recently reports of these aneurysms have increased. The differential diagnosis between FA and DA is requisite for deciding therapy or for prognosis, but it is often difficult to distinguish these aneurysms even if angiographies are conducted. The authors have treated 6 cases with FA and 5 cases with DA during the past 17 years. As the initial symptom, subarachnoid hemorrhage (SAH) was noted in all 6 cases with FA. On the other hand, 2 cases of SAH, 2 cases of brain stem infarction, and 1 case of ischemic attack were noted in DA cases. The aneurysmal locations of FA were at the vertebral artery (VA) in all 6 cases, and those of DA were at the VA in 3 cases and at the basilar artery (BA) in 2 cases. As angiographic findings of DA, pearl & string signs were demonstrated in 3 cases, and retention of contrast medium was noted in 3 cases. Diagnosis of FA is comparatively easy on angiography but when angiospasm exists, it is difficult to differentiate DA from FA. Consequently, repeated angiography is recommended. MR imaging findings of 2 cases with FA were compared with those of 3 cases with DA. No abnormal findings, excepting a dilatation of the signal-void area corresponding to the arterial blood flow were shown in FA, but various abnormalities were detected in all of the 3 cases with DA. Namely, an intimal flap and a double lumen in 1 case, intra-mural hematoma in 1 case, and a hematoma adjacent to the parent artery in 2 cases were demonstrated. Thus, MR imaging was thought to be a useful means for distinguishing between FA and DA. 相似文献
995.
To examine the details concerning that part of TRI metabolism which was carried out by the extrahepatic organs, we studied the extrahepatic metabolism of chloral hydrate (CH), free-trichloroethanol (F-TCE) and trichloroacetic acid (TCA) using a method developed in our laboratory. Bypass and non-bypass dogs were given CH, F-TCE and TCA, and we compared the concentrations these substances and their metabolites in the serum and urine of the two groups of animals. In the bypass dogs, F-TCE, TCA and conjugated-trichloroethanol (Conj-TCE) appeared in the blood and urine 30 min. after the CH administration, and TCA and Conj-TCE appeared 30 min. after the F-TCE. All levels of administered substance were higher in bypass dogs than in non-bypass dogs, and the compounds were metabolized in small amounts in the extrahepatic organs compared with the liver. Therefore, administered substances remained at high levels in the serum and were excreted in large amounts in the urine in the form of unchanged substances. The metabolized percentage volumes of CH to TCA in the bypass dogs were 10-20%, and those of F-TCE to TCA were very small, while these percentage values of CH to F-TCE were the same or slightly smaller, respectively. Moreover, trichloroethylene (TRI) acts to decrease the leukocyte count in the blood, but the TRI metabolites described above do not have this function. 相似文献
996.
K Imai K Nakajima K Eguchi M Miyazaki M Endoh Y Tomino Y Nomoto H Sakai Y Hyodo 《Nephron》1991,59(1):148-152
A 23-year-old male patient with homozygous C3 deficiency who developed asymptomatic proteinuria and hematuria was reported. Renal biopsy disclosed typical IgA nephropathy with deposition of early- and late-complement components except for C3 deposition. C9 and membrane attack complex were detected in the glomeruli despite the absence of C3. It was suggested that there might be some unknown complement activation mechanism which does not require C3 component. 相似文献
997.
Y Kumamoto T Tsukamoto S Sakai T Gouro S Maekwa K Oguma I Henmi K Igawa M Kadono S Okayama 《Hinyokika kiyo. Acta urologica Japonica》1987,33(3):471-484
The clinical efficacy of norfloxacin (NFLX) was evaluated in 74 patients having chronic prostatitis with the subjective symptoms suggesting the inflammations of prostate and more than five white bloodcells (WBCs)/hpf in their prostatic secretions (EPS). Of these, gram negative rods with greater than or equal to 10(3)CFU/ml (GNR group) were isolated from the EPS in 10 patients (13.6%) and gram positive cocci with greater than or equal to 10(3) CFU/ml (GPC group) were obtained in 46 patients (62.2%). E. coli (70.0%) was the most frequent strain isolated among GNR group and S. epidermidis (40.4%), S. aureus (19.1%), E. faecalis (17.0%) and S. haemolyticus (14.9%) were frequently isolated among the GPC group. The overall clinical efficacy of NFLX was determined at the second and fourth week by the three factors, (1) the effect on bacteria, (2) WBCs in the EPS and (3) the subjective symptoms in the patients with bacteria of greater than or equal to 10(3) CFU/ml being isolated. The overall clinical effectiveness rate was 71.4% and 100%, respectively, in the GNR group. In the GPC group, its rate was 79.3% and 88.0%, respectively. The patients with no bacteria or less than 10(3) CFU/ml isolated from the EPS had an overall clinical effectiveness rate of 89.8% at the second week and 90.0% at the fourth, when it was evaluated by the effect on WBCs and subjective symptoms. In the effect of NFLX on bacteria in the EPS, it eliminated them in 75.0% and 83.9% at the second and fourth week, respectively, of all patients with GNR or GPC of greater than or equal to 10(3) CFU/ml isolated from the EPS. The minimum inhibitory concentrations (MIC) of NFLX against E. coli isolated from the EPS was distributed from 0.025 microgram/ml to 3.13 micrograms/ml with most below 0.1 microgram/ml. Those against all other GNR were below 0.78 microgram/ml. NFLX showed good antimicrobial activities against GPC with most of MIC being distributed from 0.78 microgram/ml to 1.56 micrograms/ml. NFLX produced the highest eradication rate in bacteriological response not only against GNR such as 100% at the first, the second and fourth week but GPC as 89.2%, 93.8% and 96.0%, respectively. In the effect of NFLX on WBCs in EPS, 40-50% of patients got free from the inflammation of prostate by NFLX treatment. This became prominent in the GNR group as the treatment was continued although not in the GPC group. The subjective symptoms were improved by NFLX treatment in most of the patients. 相似文献
998.
A polypoidal adenosquamous cell carcinoma of the esophagus with a pseudosarcomatous stromal reaction
A case of a polypoidal carcinoma with a pseudosarcomatous stromal reaction is presented. Histologically, the polypoidal tumor of the lower esophagus was revealed to be an adenosquamous cell carcinoma associated with the proliferation of atypical stromal cells, osteoclastic-like giant cells, and histiocytes. Using an immunohistochemical stain, these stromal atypical cells were found to be positive for vimentin, with some cells positive for alpha 1-antichymotrypsin. However these atypical cells proved negative as epithelial markers (keratin and EMA). Thus, it was felt that such atypical stromal cells may be a reactive proliferation of the stromal cells to an adenosquamous cell carcinoma. 相似文献
999.
Pharmaceutical studies on crude drugs. I. Effect of the Zingiberaceae crude drug extracts on sulfaguanidine absorption from rat small intestine 总被引:2,自引:0,他引:2
1000.
Noboru Sakai Hiroaki Nokura Kazuki Deguchi Estela Decarlini Atsuro Futamura Hiromu Yamada 《Child's nervous system》1990,6(8):447-450
Thirty-four cases of infantile subdural effusion (ISE) were reviewed in relation to surgical treatment and its prognosis during an average of 4 years of extended follow-up. The surgical indications were determined mainly by the size of the ISE on computed tomography (CT) scan and by metrizamide CT cisternography (MCTC). Consequently, 18 cases were categorized as type A according to MCTC, including 11 cases (61.1%) of ISE CT grade 1. All type A cases were closely observed. This nontreatment regimen yielded excellent results in 15 cases (83.3%). For 10 cases categorized as type B according to MCTC, including 5 cases (50%) of ISE CT grade 3, surgical treatment was indicated and excellent results were obtained in 8 cases (80%). For 6 cases categorized as type C according to MCTC and as ISE CT grade 3, surgery yielded excellent results in 4 cases (66.7%). Antiepleptic drugs have been given to three (27.3%) of the 11 patients who had convulsive attacks. In conclusion, the surgical indications for ISE were based mainly on MCTC in addition to the clinical course, and it is emphasized that, in the early stages, surgery on ISE cases categorized as MCTC types B and C is necessary. 相似文献