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   435篇
  免费   23篇
  国内免费   1篇
儿科学   23篇
妇产科学   4篇
基础医学   31篇
口腔科学   10篇
临床医学   39篇
内科学   129篇
皮肤病学   24篇
神经病学   32篇
外科学   75篇
综合类   1篇
预防医学   20篇
眼科学   2篇
药学   29篇
肿瘤学   40篇
  2022年   2篇
  2021年   4篇
  2018年   2篇
  2017年   8篇
  2016年   2篇
  2015年   9篇
  2014年   13篇
  2013年   16篇
  2012年   8篇
  2011年   5篇
  2010年   18篇
  2009年   19篇
  2008年   6篇
  2007年   5篇
  2006年   15篇
  2005年   14篇
  2004年   9篇
  2003年   6篇
  2002年   5篇
  2001年   10篇
  2000年   3篇
  1999年   9篇
  1998年   10篇
  1997年   28篇
  1996年   22篇
  1995年   30篇
  1994年   11篇
  1993年   19篇
  1992年   14篇
  1991年   6篇
  1990年   4篇
  1989年   6篇
  1988年   4篇
  1987年   3篇
  1986年   3篇
  1985年   4篇
  1984年   4篇
  1983年   5篇
  1982年   5篇
  1981年   2篇
  1980年   3篇
  1979年   2篇
  1978年   3篇
  1974年   2篇
  1959年   7篇
  1958年   7篇
  1957年   19篇
  1956年   20篇
  1955年   12篇
  1954年   10篇
排序方式: 共有459条查询结果,搜索用时 31 毫秒
1.
We report on a case of coexistence of replacement lipomatosis with xanthogranulomatous pyelonephritis (XGP) in the same kidney associated with staghorn calculi. A 63-year-old man was admitted to hospital complaining of a right abdominal mass. Computed tomography (CT) showed renal parenchymal atrophy with extremely increased perirenal fat. Right nephrectomy was performed. Postoperative diagnosis was renal replacement lipomatosis with XGP. Renal replacement lipomatosis and XGP have several similarities in terms of clinical background and CT findings. Sometimes it is difficult to differentiate them from malignant diseases. It is extremely rare that both conditions coexist in the same kidney. To our knowledge, only one such case has been reported.  相似文献   
2.
We report on two cases of women with locally advanced squamous cell carcinoma of the urethra. Patient 1 also displayed regional lymph node metastasis. Treatment comprised combined radiotherapy to 60 Gy and chemotherapy with 5-fluorouracil and cisplatin. Complete response was obtained in both patients, including the inguinal lymph nodes of Patient 1. Patient 1 experienced recurrent inguinal lymph node metastasis on the contralateral side at 42 months after initial treatment, and the same treatment was performed followed by surgical excision. Both patients remain alive with no evidence of disease, at 12 months after recurrence in Patient 1, and at 27 months after treatment in Patient 2.  相似文献   
3.
We report the case of a female patient with bilateral metachronous adrenocortical cancer who survived long-term after adrenalectomy. In 1991, the patient underwent left adrenalectomy to remove a huge adrenal mass (10 x 9 cm) displaying no hormonal abnormality. Histological diagnosis was adrenocortical cancer. A right adrenal mass (7 x 6 cm) was found 4 years after left adrenalectomy. Right adrenalectomy was performed, and histological diagnosis was again adrenocortical cancer. The patient remains alive with no evidence of disease 8 years after last surgery.  相似文献   
4.
HtrA2 is up-regulated in the rat testis after experimental cryptorchidism   总被引:3,自引:0,他引:3  
AIM: The aim of the present study was to elucidate the role of high temperature requirement A2 (HtrA2) in germ cell loss in the heat-stressed testis. METHODS: We examined the expression of HtrA2, caspase-9 activity and proteolytic activity of HtrA2 in the rat testis, and their in vivo responses to experimental cryptorchid treatment. RESULTS: Northern analysis revealed the expression of HtrA2 mRNA peaked at days 1 and 7 after cryptorchid treatment. While expression of HtrA2 mRNA was seen in the spermatogonium, spermatocytes and some spermatids in normal adult rat testis, experimental cryptorchidism treatment resulted in a marked increase in its signal intensity in spermatocytes and some spermatids, and the layers of spermatogonium and early primary spermatocytes became negative at days 1 and 7 after the treatment. However, the spermatogonium, Sertoli cells and interstitial cells appeared to have strong intensities at days 14, 28 and 56 after the treatment. Western analysis revealed the expression of HtrA2 protein peaked at day 2 coinciding with the increase of positive spermatogonium, the appearance of protein-positive interstitial cells, and day 28 coinciding with the reappearance of protein-positive interstitial cells. Caspase-9 activity peaked at day 2 and HtrA2 proteolytic activity peaked at day 28. Consequently, the first peak of HtrA2 mRNA expression was followed by the peak of caspase-9 activity and the second peak was followed by the peak of proteolytic activity; however, the second peak of mRNA expression had considerable chronological difference from that of the protein. CONCLUSION: These findings suggest the probabilities that the heat stress results in germ cell death by a caspase-independent manner with the elevation of HtrA2 proteolytic activity, as well as a caspase-dependent manner with the elevation of caspase-9 activity.  相似文献   
5.
In order to determine the reliability of endoscopic biopsy indiagnosis of early gastric cancer, and to clarify the problemswith biopsies, preoperative endoscopic biopsies from 771 earlygastric cancer cases were reviewed and analyzed clinicopathologicallyin comparison with surgically resected specimens. The 771 cancerswere surgically resected at the National Cancer Center Hospitalduring the period from 1972 to 1982. Definite histological diagnosiswas obtained in 87.4% of the carcinomas at the initial biopsies.Repeated biopsy raised the percentage of correct definite diagnosesto 96.1%. False-negative (including suspicion of cancer) diagnosiswas most frequent in the case of depressed lesions (50 lesions).Half of the false negatives were found to be due to samplingerrors by the endoscopists. The other half of these 50 lesionswere diagnosed as "suspicious of malignancy" because of thehistological difficulty in differentiating early gastric cancerfrom regenerative atypia with intestinal metaplasia, or becausethere was not enough information, or for the other reasons.Most of the 31 false-negative diagnoses at the initial biopsyfrom elevated lesions were reported as adenoma (group III) orsuspicious of carcinoma (group IV), indicating that differentialdiagnosis between well-differentiated adenocarcinoma and adenomais very difficult. The result of the present study suggeststhat repeated biopsy from correct sites and discussion of thelesions between clinicians and pathologists are very important. **Present affiliation: Toranomon Hospital, Toranomon 2-2-2,Minato-ku, Tokyo 105, Japan.  相似文献   
6.
One hundred Suc-X-Y-Ala-pNA peptides (SUC: succinyl, pNA: p-nitroanilide, X, Y: Gly, Ala, Val, Leu, Ile, Phe, Pro, x-aminobutyric acid, norvaline, norleucine) were synthesized and their reaction constants with porcine pancreatic elastase (Km, Kcat and Kcat/Km) were determined. These reaction constants were quantitatively analyzed using the Free–Wilson/Fujita–Ban method. The contribution of amino acid side chains to the reaction constants Km, Kcat and Kcat/Km), expressed logarithmically, was found to be additive. On the other hand, 19 elastase inhibitors of the general formula CF3CO-X-Y-Ala-pNA (X,Y: ten amino acids) were synthesized, and their inhibition constants were compared with the Michaelis constant for the corresponding substrates and analyzed using free-energy-related substituent constants. In the analysis of amino acid side chains in the Y position, the Ki value of the inhibitor was generally correlated to the Km value of the substrate, which corresponded to the inhibitor, thus confirming the validity of the equation This study may serve as a prototypical approach to unraveling structure–activity relationships of peptide substrates and inhibitors of medicinal or agricultural importance.  相似文献   
7.
As a means of preparation of biocompatible molecular surfaces, an alternate assembly of charged polysaccharides and oppositely-charged synthetic polymers was conducted. Cationic chitosan was assembled alternately with anionic poly(sodium styrenesulfonate) (PSS) at pH 4. Regular film growth and its dependence on ionic strength were detected by the quartz crystal microbalance (QCM) method. Averaged film thicknesses for the chitosanCPSS layer were 15, 31, 46, and 69 A° , respectively, when 0, 0.25, 0.5, and 1 M of NaCl was contained in aqueous chitosan. Adsorption of chitosan did not reach saturation in 20 min at 0 M NaCl, while the adsorption became saturated within 6 min with 0.25 M NaCl. Anionic sodium chondroitin sulfate was also assembled in alternation with cationic poly(dimethyldiallylammonium chloride) (PDDA) at pH 6.5. The adsorption of chondroitin sulfate was less sensitive to ionic strength. Surface morphology of chitosan–PSS films was investigated by non-contact atomic force microscopy (AFM) observation. Maximum height difference and Ra value for a 1000 × 1000 nm area were 11 and 0.69 nm, respectively, indicating the formation of a molecularly flat surface by alternate layer-by-layer adsorption.  相似文献   
8.
9.
10.
Aim: To assess the physical and mental burdens associated with expressing empathy with another person's stress. Methods: Nine female subjects listened to their partner's negative emotions aroused by a stress task (Stroop color‐word test) under two conditions. In the first, the subject reacted empathetically to their partner (“with empathy”); in the second, the subject offered no response (control). Electroencephalograms and skin temperature of the second finger were recorded during the test. Subjective stress was estimated using a visual analog scale, whereas the level of cognition was expressed on a five‐point ranking. Responses during and after expressions of empathy were examined by comparisons with control or by correlation. Results: Sympathetic nerve tone increased under both conditions (i.e. the skin temperature of the second finger fell). Subjective stress was not recognized by the subject while listening “with empathy”, although it did increase significantly after the subject has listened “with empathy”. Subjective stress was not felt under the control conditions. Right temporal activity while listening showed a significantly positive correlation with the level of cognition of feeling the same emotion as the stressed partner, whereas bilateral frontal activity after listening was significantly negative correlated with the level of cognition of understanding the emotions of the stressed partner. Conclusion: Expressing empathy with another person's negative emotion led to increased physiological activity and subjective stress. Physiological responses to empathy depended on cognition of the different subjective factors. Cognition of sharing negative emotions activated the right temporal region of the brain, whereas cognition of understanding negative emotions inhibited bilateral frontal activities.  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