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   4272篇
  免费   230篇
  国内免费   33篇
耳鼻咽喉   21篇
儿科学   109篇
妇产科学   50篇
基础医学   582篇
口腔科学   66篇
临床医学   230篇
内科学   1015篇
皮肤病学   61篇
神经病学   397篇
特种医学   114篇
外科学   811篇
综合类   27篇
预防医学   80篇
眼科学   44篇
药学   333篇
中国医学   21篇
肿瘤学   574篇
  2023年   28篇
  2022年   36篇
  2021年   93篇
  2020年   49篇
  2019年   80篇
  2018年   101篇
  2017年   89篇
  2016年   89篇
  2015年   101篇
  2014年   133篇
  2013年   148篇
  2012年   232篇
  2011年   288篇
  2010年   166篇
  2009年   106篇
  2008年   195篇
  2007年   232篇
  2006年   254篇
  2005年   225篇
  2004年   239篇
  2003年   175篇
  2002年   221篇
  2001年   101篇
  2000年   118篇
  1999年   136篇
  1998年   60篇
  1997年   40篇
  1996年   47篇
  1995年   30篇
  1994年   42篇
  1993年   45篇
  1992年   66篇
  1991年   56篇
  1990年   55篇
  1989年   58篇
  1988年   45篇
  1987年   45篇
  1986年   63篇
  1985年   42篇
  1984年   32篇
  1983年   32篇
  1982年   14篇
  1981年   10篇
  1980年   13篇
  1979年   10篇
  1977年   11篇
  1975年   12篇
  1973年   11篇
  1968年   8篇
  1966年   8篇
排序方式: 共有4535条查询结果,搜索用时 15 毫秒
1.
2.
MK-0787 (Imipenem)/MK-0791 (Cilastatin sodium), a new compound of Thienamycin, was administered in treatment of 35 patients (36 cases) with chronic complicated UTI or for prevention of serious infections with much complicated factors. The patients were principally treated at a daily dose of 1 g for over 10 days. The efficacy rate of 26 patients who were evaluable in the early phase (4-7 days) was 88.5%, while it became up to 92.3% in the final phase judgment. As for clinical usefulness, the result was obtained to be as high as that of the clinical efficacy. In bacteriological study, 35 strains were clinically isolated including 7 strains of P. aeruginosa from UTI. All the strains disappeared with an eradication rate of 100% after treatment. Strains appearing after Imipenem/Cilastatin sodium treatment mainly consisted of fungi. Usefulness judgements tended to be greater in the final phase than in the early phase. As for side effects, vomiting was recorded in one case, in which the administration was discontinued. In laboratory findings there were 3 cases with elevated GPT, 2 cases with elevated GOT, one case with elevated gamma-GTP, one with thrombocytopenia, and one with eosinophilia each, but these abnormal values were slight and transient. In summary our clinical study showed that Imipenem/Cilastatin sodium was a very effective antibiotic in treatment on moderate or serious UTI or preventive use for infections in compromised hosts. Considering the features of this agent, it might be more effective and useful for clinical use in treatment on polymicrobial infections including stubborn organisms than any other antimicrobial compounds. Furthermore, it was safe and well tolerable in a long term treatment.  相似文献   
3.
Recently, we examined 2 cases of hypertrophic cardiomyopathy (HCM) presenting with sustained ventricular tachycardia (VT). One case was a 62 year old male with midventricular hypertrophy and monomorphic sustained VT. After admission, the efficacies of procainamide, disopyramide, aprindin, flecainide, mexiletine and verapamil were evaluated by means of continuous electrocardiographic monitoring. Verapamil prevented the recurrence of sustained VT and markedly reduced the frequency and number of runs of nonsustained VT. In the electrophysiologic study, rapid VT was induced by double extrastimuli at the right ventricular apex. Intravenous verapamil at a dose of 10 mg prevented the induction of VT. The patient was discharged on verapamil and remains asymptomatic after 3 months of follow up. The other case was a 34 year old female who was a survivor of cardiac arrest. Monomorphic VT was observed on emergency admission and was converted to sinus rhythm by direct current cardioversion after resuscitation. In the electrophysiologic study, rapid VT was induced by double extrastimuli at the right ventricular outflow tract. Verapamil at a dose of 10 mg prevented the induction of VT. These 2 cases of HCM are rare in that they presented with sustained VT. It is also of interest that verapamil, which has been used conventionally in HCM, prevented VT.  相似文献   
4.
Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity.  相似文献   
5.
6.
Vasopressin, a hormone secreted from the posterior lobe of the hypophysis, has endocrinological and antidiuretic effects; it contracts vessels and smooth muscles, especially intestinal smooth muscle. In the present study, we investigated the role of vasopressin (Pitressin: arginine-vasopressin) in elimination of intestinal gas on excretory urography reading. Sixty outpatients were randomly divided into six groups. In Group I, the routine procedure was employed, i.e. laxatives the previous night and NPO the morning of the examination. In Groups II to VI, different dose regimens were employed: 6 or 10 units of Pitressin was administered by subcutaneous injection 30 minutes prior to injection of a contrast medium, with or without NPO. Intestinal gas elimination was evaluated by X-ray films taken before and after injection of Pitressin. The efficacy was rated by four grades. There were no significant differences in the gas elimination or occurrence of side effects between any two groups. Younger patients seemed to respond quickly to Pitressin and good effects were obtained. These results indicate that the pretreatment for excretory urography with 6 units of Pitressin without NPO may be a safe and effective alternative method for elimination of intestinal gas, in particular for young patients.  相似文献   
7.
Abstract: Light microscopic observations on the superficial pineal gland of Wistar-King rats were made to examine whether or not pineal volume and pinealocyte size, expressed as nuclear density, at daytime or nighttime are affected by long-term exposure to 50 Hz rotating magnetic field (MF) at 5.0 μT. Determinations of pineal volume and pinealocyte size were repeated twice (April and October) during the year. Size of pinealocytes in MF-exposed and sham-exposed rats exhibited, in addition to the difference between peripheral and central regions, regional differences in a proximodistal direction; pinealocytes in the distal and middle-peripheral regions were usually larger than those in the proximal and middle-central regions at daytime or nighttime. In October, distal and proximal pinealocytes showed significant day-night changes in size in sham-exposed rats, but not in MF-exposed animals. The situations in the two groups were almost reversed in April. Significant day-night differences were scarcely found in pinealocyte size in the middle region in the two groups. Throughout the study, pineal volume and pinealocyte size in each region were generally the same between MF-exposed and sham-exposed rats at daytime or nighttime. The results suggest that pinealocytes in the distal and proximal regions, but not those in the middle region, are affected by MF-exposure; day-night differences in sizes of distal and proximal pinealocytes appear in April and disappear in October under the influence of MF. MF may exert an effect on mechanisms controlling day-night rhythms of pinealocyte size in the rat.  相似文献   
8.
A 47-year-old male was concerned with a large AVM involved extensively in the parietal region and the posterior fossa. Radiological examinations showed multiple radiolucencies in the parietal and occipital bone and torturous vascular nets (nidus) in those bones on the angiograms. Nidus was found also in the dura mater in the posterior fossa. Therefore, this case seemed to be an extremely rare case of calvarial AVM in the parietal region with the mixed calvarial dural AVM in the posterior fossa. His symptoms were bruit, transient hemiparesis and Gerstmann's syndrome in addition to the symptoms due to raised intracranial pressure. Favorable results of therapies could be attained by extensive exfoliation of dura mater from the cranial bone and incision of proximal dura mater in the sinus.  相似文献   
9.
The significance of preoperative chemoembolization using ethiodized oil, cisplatin and gelatin sponge (Sandwich therapy) for resectable hepatocellular carcinoma (HCC) was evaluated. One hundred and thirteen patients with solitary and less than 10 cm sized HCC who underwent radical hepatic resection were chosen for this study. Fifty-three patients received Sandwich therapy before surgery (Group A), and the remaining 60 patients under-went surgery without any preoperative treatments (Group B). Any background factors between two groups were not significantly different. The anticancer effects of this therapy were evaluated by histologic examination in 31 patients who had preoperative Sandwich therapy. In 22 of 31 patients (71%), the main nodules were completely necrotic. The ratios of patients with complete necrosis in daughter nodules were 7/12 (58%), in portal vein tumor emboli, 7/10 (70%), in intracapsular invasions, 11/21 (52%), in extracapsular invasions, 4/11 (36%). The 4-year disease-free survival rates in Group A and Group B were 56% and 27% respectively, and the rate of the former was significantly higher than that of the latter (p less than 0.05). The 4-year survival rates in Group A and Group B were 83% and 53% respectively. The rate of Group A was also significantly higher than that of Group B (p less than 0.01). We concluded that preoperative Sandwich therapy was very significant to obtain successful long-term disease-free survival and survival in regard to relatively early stage HCC.  相似文献   
10.
We used morphological, biochemical and immunohistochemical methods to assess the response of Müller cells after experimental lensectomy-vitrectomy in rabbits. We observed widened intercellular spaces between the Müller cells and nerve fibers of ganglion cells, and increased electron opacity in the Müller cells of eyes injected with silicone oil. No apparent morphological changes were detected in the Müller cells of air-injected eyes. The specific and total activities of Müller cell-marker enzymes (glucose 6-phosphatase and glutamine synthetase) showed an initial increase, followed by a decrease. Glial fibrillary acidic protein immunoreactivity was not found in the Müller cells of the normal rabbit retina but was exhibited after surgery. Our results showed that markers of Müller cells associated with glycogenolysis and/or gluconeogenesis, glutamate-glutamine cycle and cytoskeletal protein metabolism were affected by the experimental lensectomy-vitrectomy.  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