首页 | 官方网站   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   10712篇
  免费   429篇
  国内免费   30篇
医药卫生   11171篇
  2022年   75篇
  2021年   149篇
  2020年   82篇
  2019年   116篇
  2018年   147篇
  2017年   95篇
  2016年   122篇
  2015年   172篇
  2014年   212篇
  2013年   297篇
  2012年   492篇
  2011年   576篇
  2010年   314篇
  2009年   253篇
  2008年   547篇
  2007年   607篇
  2006年   563篇
  2005年   587篇
  2004年   605篇
  2003年   578篇
  2002年   611篇
  2001年   378篇
  2000年   399篇
  1999年   319篇
  1998年   140篇
  1997年   99篇
  1996年   96篇
  1995年   100篇
  1994年   81篇
  1993年   78篇
  1992年   194篇
  1991年   183篇
  1990年   155篇
  1989年   190篇
  1988年   146篇
  1987年   150篇
  1986年   144篇
  1985年   154篇
  1984年   105篇
  1983年   109篇
  1982年   42篇
  1981年   51篇
  1980年   44篇
  1979年   75篇
  1978年   50篇
  1977年   39篇
  1975年   43篇
  1970年   43篇
  1968年   39篇
  1967年   43篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Two patients with mesenteric panniculitis are presented. In the first patient, a provisional diagnosis of ileus was made, based on the clinical features and imaging data. Laparotomic findings showed that the ileum was bound tightly by a fibrous strip and dilated, with thickened and swollen mesentery. Incision of the fibrous strip was performed, and the clinical symptoms were improved. The second patient was strongly suspected to have mesenteric panniculitis, from characteristic features on abdominal computed tomography and barium enema. Conservative therapy was effective in this case. We emphasize the variety of clinical courses in mesenteric panniculitis, requiring selection of the most suitable treatment.  相似文献   
2.
Intraventricular hemorrhage (IVH) in preterm infants is well known to be associated with the high morbidity and mortality of this group. Previous studies have suggested altered cerebral blood flow (CBF) as an important pathologic factor. We measured the CBF in nearterm rabbit fetuses using the hydrogen clearance technique. The local CBF of the rabbit fetuses was significantly low compared with that of the maternal rabbits. The response of CBF to changes in PaCO2 was observed in rabbit fetuses. The CO2 reactivity index of the fetal rabbit was lower than that of the maternal rabbit. This low CO2 reactivity might reflect the immaturity of the fetal brain and its low CBF. We were unable to monitor the fetal blood pressure, but the fetal CBF remained stable when the maternal blood pressure was altered. It is well known that IVH in preterm infants originates from the subependymal germinal matrix and that this has many fragile vessels. Our observation suggests that even a small increase of CBF during hypercapnia might have a large effect towards producing hemorrhage.  相似文献   
3.
4.
Journal of Neurology - A high incidence of valvular heart disease in Parkinson's disease (PD) patients treated with ergot-derived dopamine agonists, such as cabergoline and pergolide, has been...  相似文献   
5.
Neuronavigation has become an effective therapeutic modality and is used routinely for intra-axial tumor removal. This retrospective study was conducted to evaluate the clinical impact of neuronavigation and image-guided extensive resection for adult patients with supratentorial malignant astrocytomas. Between 1990 and 2002, 76 adult patients with pathologically confirmed malignant astrocytomas underwent craniotomy and removal of the tumors at the Toyama Medical and Pharmaceutical University Hospital. Of these 76 patients, 42 were treated using neuronavigation with conventional microneurosurgery and the other 34 were treated with conventional microneurosurgery alone. Postoperative early MRI with contrast enhancement was done, and gross total resection was defined as the complete absence of residual tumor. Survival time was analyzed with the Kaplan-Meier method. Prognostic factors were obtained from the Cox proportional hazards model. In univariate analysis, age (< 65), grade 3, preoperative KPS (>/= 80), use of neuronavigation, and gross total resection were significantly associated with longer survival. However, when the data were submitted to multivariate analysis, grade 3, preoperative KPS (>/= 80), and gross total resection were independent prognostic factors. The median survival periods of patients receiving gross total resection (vs. partial resection) and neuronavigation (vs. no neuronavigation) were 16 (vs. 9) months and 16 (vs. 10) months, respectively. The percentage of a gross total resection was significantly higher in the neuronavigation group compared to that in the no-navigation group (64.3 % vs. 38.2 %, p < 0.05). Neurological deterioration occurred in 4 of 42 (9.5 %) and in 6 of 34 (17.6 %) patients after surgery with neuronavigation and surgery without neuronavigation, respectively, although this difference was not statistically significant. Our results showed that neuronavigation increases the radicality in the resection of malignant astrocytomas and is objectively useful for improving survival time.  相似文献   
6.
H Yamamoto  S Tsuji  Y Nagai 《Brain research》1991,558(1):117-119
We established a MAb N-25 reacted with a minor unknown antigen (AgX) in a commercially available GQ1b sample. It also recognized minor antigens in bovine brain (X-1, 2, 3, 4 and 5) and cultured neural cell lines (X-1). AgX is identical to X-5. X-5 is sialidase sensitive and has the common structure as X-1, which is resorcinol positive. These results suggested that novel gangliosides exist in bovine brain and neural cell lines.  相似文献   
7.
OBJECTIVE: Standard chemotherapy shows relatively low long-term survival in patients with poor-risk testicular germ cell tumor (GCT). First-line high-dose chemotherapy (HD-CT) may improve the result. High-dose carboplatin, etoposide, ifosfamide chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT) was investigated as first-line chemotherapy in patients with advanced testicular GCT. METHODS: Fifty-five previously untreated testicular GCT patients with Indiana 'advanced disease' criteria received three cycles of bleomycin, etoposide and cisplatin (BEP) followed by one cycle of HD-CT plus PBSCT, if elevated serum tumor markers were observed after three cycles of the BEP regimen. RESULTS: Thirty patients were treated with BEP alone, because the tumor marker(s) declined to normal range. Twenty-five patients received BEP and HD-CT. One patient died of rhabdomyolysis due to HD-CT. Three and six (13% and 25%) out of 24 patients treated with BEP and HD-CT achieved marker-negative and marker-positive partial responses, respectively. The other patients achieved no change. Fifteen (63%) are alive and 14 (58%) are free of disease at a median follow-up time of 54 months. Severe toxicity included treatment-related death (4%). CONCLUSIONS: HD-CT with peripheral stem cell support can be successfully applied in a multicenter setting. HD-CT demonstrated modest anticancer activity for Japanese patients with advanced testicular GCT and was well tolerated. This regimen might be examined for further investigation in randomized trials in first-line chemotherapy for patients with poor-risk testicular GCT.  相似文献   
8.
The thermal conversion of 1 alpha-hydroxyprevitamin D3 (1 alpha-OH-previtamin D3) diacetate to 1 alpha-hydroxyvitamin D3 (1 alpha-OH-vitamin D3) diacetate was investigated in five solvents. The fraction of 1 alpha-OH-vitamin D3 diacetate was calculated from the HPLC peak areas (UV detection) of 1 alpha-OH-previtamin D3 diacetate and 1 alpha-OH-vitamin D3 diacetate. When 1 alpha-OH-previtamin D3 diacetate was dissolved in ethanol, benzene, toluene, isopropyl ether, or n-hexane, and heated at 60 degrees C, the yield of 1 alpha-OH-vitamin D3 diacetate increased during the first 4 h, and reached an equilibrium level after 8.5 h. Differences in the ratio of 1 alpha-OH-previtamin D3 diacetate to 1 alpha-OH-vitamin D3 diacetate at thermal equilibrium, and in the rate of the thermal isomerization were observed among these five solvents. Molecular mechanics (MM) calculations were performed in order to estimate solvent effects on conformation for 1 alpha-OH-previtamin D3 diacetate and 1 alpha-OH-vitamin D3 diacetate. The solvent effect was treated by specifying a dielectric constant representative of each of the three solvents: ethanol (polar), n-hexane (nonpolar), and benzene (aromatic). The dielectric constants used were 24.3 for ethanol, 1.5 for n-hexane, and 2.3 for benzene. It is suggested that the conformation of 1 alpha-OH-vitamin D3 diacetate is stabilized in polar solvent. However, the order of conformational stability when solvent effects are included in the calculations is: ethanol greater than benzene greater than n-hexane. This order does not follow the experimental results. The proton NMR chemical shifts of 1 alpha-OH-vitamin D3 diacetate are different in deuterated n-hexane, ethanol, and benzene. The downfield shift of the C-6 vinyl proton of 1 alpha-OH-vitamin D3 diacetate, when compared to the chemical shift in benzene, is 0.15 and 0.11 ppm relative to the chemical shift in n-hexane and ethanol, respectively, and that of the C-7 proton was 0.30 and 0.33 ppm, respectively. No significant proton shift of 1 alpha-OH-previtamin D3 diacetate is recorded in these three solvents. To account for the increased ratio of 1 alpha-OH-vitamin D3 diacetate to 1 alpha-OH-previtamin D3 diacetate ratio in benzene, we suggest that 1 alpha-OH-vitamin D3 diacetate may be stabilized via specific solute-solvent interactions in benzene.  相似文献   
9.
Sixteen malignant tumors of soft tissue (15 cases) were treated with low voltage direct current (DC therapy) with or without systemic chemotherapy. Two platinum or stainless steel electrodes were placed in the tumor and around 10 volts of direct current was passed for 1 hour. In cases in which chemotherapy was performed, single or combined anticancer agents consisted of ADM and BLM were administered simultaneously with DC therapy by systemic route. Ten cases (11 tumors) out of 15 cases received no other local treatment. Histological examination was performed in 6 of 11 lesions, and in all lesions pathological therapeutic effects were recognized. Decrease in tumor size was observed in 9 lesions. In 2 cases the tumors disappeared completely after DC therapy only. In one case receiving DC therapy with chemotherapy, the tumor decreased dramatically and became resectable. Main complications were slight pain during treatment and slight fever after treatment, but special treatment for these complications was not necessary. Our results suggested that DC therapy with or without systemic chemotherapy was useful for local control of malignant tumors. And also if DC therapy had been performed simultaneously with chemotherapy the therapeutic effects seemed to be more emphasized than single use of these therapies.  相似文献   
10.
A 52‐year‐old Japanese woman who presented with gastrointestinal (GI) bleeding underwent a proximal gastrectomy for a gastrointestinal stromal tumor (GIST) with a foveolar hyperplasia at the apex of the tumor, 4.5 cm in size, located in the upper body of the stomach. Although GIST are often asymptomatic and are found only incidentally, clinical symptoms such as bleeding, abdominal pain, or obstruction, occasionally lead to a premorbid diagnosis. When submucosal tumors present GI bleeding, the source of the bleeding usually is an ulceration of the mucosa over the tumor. However, in the present study, it was thought that the bleeding originated from the region of foveolar hyperplasia.  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-23

京公网安备 11010802026262号