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   8663篇
  免费   479篇
  国内免费   35篇
耳鼻咽喉   156篇
儿科学   106篇
妇产科学   94篇
基础医学   971篇
口腔科学   155篇
临床医学   584篇
内科学   2317篇
皮肤病学   182篇
神经病学   516篇
特种医学   532篇
外科学   1567篇
综合类   37篇
预防医学   262篇
眼科学   135篇
药学   611篇
中国医学   39篇
肿瘤学   913篇
  2023年   40篇
  2022年   103篇
  2021年   186篇
  2020年   98篇
  2019年   137篇
  2018年   178篇
  2017年   147篇
  2016年   186篇
  2015年   174篇
  2014年   227篇
  2013年   259篇
  2012年   451篇
  2011年   497篇
  2010年   269篇
  2009年   272篇
  2008年   460篇
  2007年   423篇
  2006年   432篇
  2005年   455篇
  2004年   412篇
  2003年   418篇
  2002年   369篇
  2001年   270篇
  2000年   291篇
  1999年   280篇
  1998年   103篇
  1997年   64篇
  1996年   72篇
  1995年   62篇
  1994年   62篇
  1993年   43篇
  1992年   177篇
  1991年   147篇
  1990年   139篇
  1989年   141篇
  1988年   124篇
  1987年   126篇
  1986年   125篇
  1985年   114篇
  1984年   83篇
  1983年   57篇
  1981年   27篇
  1979年   51篇
  1978年   25篇
  1977年   42篇
  1975年   26篇
  1974年   26篇
  1971年   37篇
  1969年   29篇
  1968年   29篇
排序方式: 共有9177条查询结果,搜索用时 31 毫秒
11.
Some reports have been written about hypokalemic periodic paralysis dealing with cardiac dysfunction and arrhythmia during the paralytic attack. However, no reports have been written about the cardiac function during the attack in cases of normokalemic periodic paralysis. So, we investigated cardiac function in two patients with normokalemic periodic paralysis. A 3.0 g dose of KCl was administered orally to the patients (1 male, 1 female) and 10 healthy volunteers (5 males, 5 females). Cardiac function by using ejection time (ET)/pre-ejection period (PEP), grasping power, and the level of plasma catecholamine were measured during the paralytic attack. Changes in the patients were compared with those in the volunteers. Next, a 3.0 g dose of KCl was administered to the patient, followed by intravenous dosing of 10% NaCl (50 ml) after which ET/PEP and grasping power measured. Lastly, a 60 mg dose of diltiazem, a 10 mg dose of nifedipine or a 80 mg dose of verapamil were administered, followed by a 3.0 g dose of KCl after which ET/PEP and grasping power were measured again. Thirty minutes after the administration of KCl, the grasping power decreased remarkably, from 32.0 kg to 17.0 kg in the male patient and from 30.0 kg to 20.0 kg in the female patient. By contrast, the ET/PEP showed a clear increase, from 3.47 to 6.17 in the male patient and from 2.84 to 5.45 in the female patient. Grasping power of the volunteers, however, did not change remarkably (avg. 40.3 kg before vs. 40.9 kg after in the males and avg. 26.9 kg before vs. 26.0 kg after in the females) and ET/PEP of the volunteers did not change remarkably (avg. 3.37 before vs. 3.17 after in the males and avg. 3.30 before vs. 3.43 after in the females). No significant changes were found in the levels of plasma catecholamine during the paralytic attack.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
12.
We evaluated nitric oxide induction in antitumor therapy consisting of anti–CD3 monoclonal antibody (anti–CD3) and interleukin–2 (IL–2), then determined the effect of nitric oxide reduction with L–NG–monomethyl arginine (LNMA) on the therapeutic methods. Female C57BL/6 mice, MCA102 (a non immunogenic, NK–resistant murine fibrosarcoma cell line), and 145–2C11 (hamster anti–murine–CD3 mAb) were utilized in an experimental hepatic metastasis model developed by injecting a tumor cell suspension into the spleen of mice. A marked increase in serum NO2+ NO1 was observed at 19 hours after anti–CD3 (10 μ, IV) and additional IL–2 administrations (40times101 U, twice, If) induced a further increase. The NO2, + NO3- elevation in spot urine in the combination therapy was not suppressed with LNMA at a dose of 100 μg/h but was significantly lowered at 300 μg/h. The efficacy of the anti–CD3 + IL–2 therapy was not diminished by LNMA administration either at 100 μg/h or at 300 μg/h.  相似文献   
13.
The histological findings of the patellar cartilage were compared between cases of chondromalacia, which occurs predominantly in young persons (22 patients, average age 19.8 years) and cases of osteoarthritis, which is common among the elderly (21 patients, average age 65.4 years). The histological findings of cartilage in the chondromalacia were characterized by increased density and vigorous fibrous metaplasia of chondrocytes. These findings may be considered to represent a reactive change in the chondrocyte. Cartilage degeneration in osteoarthritis, by contrast, is regressive and presents a clearly different histological picture from that of chondromalacia patellae. We conclude that chondromalacia does not easily lead to osteoarthritis. On the other hand, the cartilage was characteristically softened, as observed by gross inspection, and showed rarefaction of the cartilage matrix. It should be noted that the change was not observed in aging, but showed a pattern of cartilage degeneration peculiar to young patients with chondromalacia patellae.  相似文献   
14.
BACKGROUND: The precise mechanism of high altitude pulmonary oedema (HAPE) remains unclear. The purpose of this study was to evaluate the role of cytokines and P-selectin in the development of HAPE which occurred at moderate altitude in Japan. METHODS: The following cellular and biochemical markers and chemotactic cytokines were measured in the bronchoalveolar (BAL) fluid from four patients with HAPE at 2857-3180 m in the Japanese Alps: total proteins, albumin, lactate dehydrogenase (LDH), and interleukin (IL)-1 alpha, IL-1 beta, IL-1 receptor antagonist (ra), IL-6, IL-8, IL-10, tumour necrosis factor (TNF)-alpha, and the soluble form of P-selectin. RESULTS: At admission there were significant increases in the levels of total cells, especially macrophages and neutrophils, total protein, albumin and LDH when compared with 13 healthy individuals. Furthermore, the levels of IL-1 beta, IL-6, IL-8, and TNF-alpha were also considerably increased but returned quickly to the normal ranges or were not detected after recovery. The levels of IL-1 alpha, IL-10, and P-selectin did not change. CONCLUSIONS: These results suggest that an inflammatory process almost identical with acute respiratory distress syndrome (ARDS) may occur in HAPE, but that these changes are transient and are not associated with any increase in P-selectin levels in the BAL fluid.  相似文献   
15.
16.
Objectives and design: The aim of this study was to investigate whether the exposure of mast cells (MCs) to bacterial components affects the expression of Toll-like receptor (TLR) 4, and to elucidate the behavior of MCs during the early response to infection. Materials: Two human MC lines, HMC-1 and LAD2, were employed. Messenger RNA expression was observed by RT and real-time PCR. TLR4 expression was determined by Western blotting. TNF-α secretion was analyzed with ELISA. The degranulation ratio was measured with betahexosaminidase assay. Results: Although bacterial components increased TLR4 mRNA, only lipopolysaccharide (LPS) augmented the TLR4 protein expression. LAD2 pre-treated with LPS for 8 h resulted in 2-fold increased TNF-α secretion on LPS restimulation. Conclusion: These results suggest that the exposure of MCs to LPS may reinforce the innate immune system due to up-regulation of MC TLR4, followed by increased TNF-α release. Received 20 April 2006; returned for revision 14 July 2006; accepted by G. Wallace 11 August 2006  相似文献   
17.
We previously selected a group of hypertension candidate genes by a key word search using the OMIM database of NCBI and validated 525 coding single nucleotide polymorphisms (SNPs) in 179 hypertension candidate genes by DNA sequencing in a Japanese population. In the present study, we examined the association between 61 non-synonymous SNPs and blood pressure variations and hypertension. We used DNA samples taken from 1,880 subjects in the Suita study, a population-based study using randomly selected subjects. Analyses of covariance adjusting for age, body mass index, hyperlipidemia, diabetes, smoking, drinking, and antihypertensive medication revealed that 17 polymorphisms in 16 genes (APOB, CAST, CLCNKB, CTNS, GHR, GYS1, HF1, IKBKAP, KCNJ11, LIPC, LPL, P2RY2, PON2, SLC4A1, TRH, VWF) were significantly associated with blood pressure variations. Multivariate logistic regression analysis with adjustment for the same factors revealed that 11 polymorphisms in 11 genes (CAST, CTLA4, F5, GC, GHR, LIPC, PLA2G7, SLC4A1, SLCI8A1, TRH, VWF) showed significant associations with hypertension. Five polymorphisms in five genes, CAST(calpastatin), LIPC (hepatic lipase), SLC4A1 (band 3 anion transporter), TRH (thyrotropin-releasing hormone), and VWF (von Willebrand factor), were significantly associated with both blood pressure variation and hypertension. Thus, our study suggests that these five genes were susceptibility genes for essential hypertension in this Japanese population.  相似文献   
18.
19.
Ryo Hattori  MD    Tateki Kubo  MD    Kenji Yano  MD  PhD    Atsushi Tanemura  MD    Yuji Yamaguchi  MD  PhD    Satoshi Itami  MD  PhD    Ko Hosokawa  MD  PhD 《Dermatologic surgery》2003,29(10):1071-1072
BACKGROUND: Nevus lipomatosus cutaneous superficialis (NLCS) is a relatively rare condition. Although NLCS can affect any region of the entire body, no case of NLCS in the clitoris has ever been reported. OBJECTIVE: To report a case of NLCS of the clitoris that presented manifestations that were similar to female pseudohermaphrodism. METHODS: This is a case report and review of the literature. RESULTS: A congenital, soft, skin-colored lesion of the clitoris in a 1-year-old girl resembled female pseudohermaphrodism. It was resected, and the histologic diagnosis was NLCS. Postoperatively, there was no subsequent change in the lesion during the 3-year follow-up period. CONCLUSION: We reported a case of congenital solitary NLCS of the clitoris. Although NLCS might be a relatively rare condition, we should consider it in the differential diagnosis of female pseudohermaphrodism.  相似文献   
20.
In order to estimate the diagnostic validity of chemical fecal occult blood tests, i.e. orthotolidine (Shionogi A) and guajac (Shionogi B) slides for detecting cancers of the esophagus, stomach and colorectum, the authors followed up all the examinees (n=3,449) of comprehensive medical check-ups at the Center for Adult Diseases, Osaka, by means of record linkage to the Osaka Cancer Registry's files. Then, diagnostic validity was calculated based on the results of two years' follow-up. Sensitivity for the respective cancers was 20.0%, 11.8% and 62.5% for Shionogi A, and 20.0%, 5.9% and 43.8% for Shionogi B slides. Likelihood ratio for the respective cancers was 1.4, 0.8 and 4.5 for Shionogi A, and 3.3, 1.0 and 7.5 for Shionogi B. Specificity was analogous among the three cancer sites, being 86% for Shionogi A and 94% for Shionogi B. These results suggest that the diagnostic validity of chemical occult blood tests for detecting cancers of the esophagus and the stomach is very poor, and therefore imply that close examinations of these sites for screening positives is unnecessary in mass screenings for colorectal cancer.  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