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   1280篇
  免费   68篇
  国内免费   5篇
耳鼻咽喉   3篇
儿科学   41篇
妇产科学   11篇
基础医学   115篇
口腔科学   10篇
临床医学   67篇
内科学   359篇
皮肤病学   14篇
神经病学   81篇
特种医学   56篇
外科学   228篇
综合类   6篇
预防医学   42篇
眼科学   43篇
药学   60篇
中国医学   2篇
肿瘤学   215篇
  2023年   6篇
  2022年   24篇
  2021年   40篇
  2020年   18篇
  2019年   26篇
  2018年   33篇
  2017年   16篇
  2016年   25篇
  2015年   25篇
  2014年   41篇
  2013年   51篇
  2012年   57篇
  2011年   58篇
  2010年   33篇
  2009年   27篇
  2008年   46篇
  2007年   47篇
  2006年   54篇
  2005年   68篇
  2004年   59篇
  2003年   65篇
  2002年   82篇
  2001年   60篇
  2000年   41篇
  1999年   45篇
  1998年   18篇
  1997年   12篇
  1996年   10篇
  1995年   13篇
  1994年   17篇
  1993年   7篇
  1992年   16篇
  1991年   17篇
  1990年   25篇
  1989年   20篇
  1988年   22篇
  1987年   17篇
  1986年   25篇
  1985年   24篇
  1984年   17篇
  1983年   9篇
  1982年   3篇
  1981年   6篇
  1980年   3篇
  1979年   4篇
  1975年   4篇
  1974年   3篇
  1968年   2篇
  1966年   2篇
  1965年   3篇
排序方式: 共有1353条查询结果,搜索用时 46 毫秒
991.
Porphyromonas gingivalis and Treponema denticola have been found together in lesions of human periodontitis. We examined the ability of a mixed infection by both bacteria to synergistically form abscesses and disturb immune responses in mice. Absorbance of an invasive P. gingivalis 16-1 strain grown in tryptic soy broth and T. denticola ATCC 33520 strain grown in TYGVS medium were adjusted. BALB/c mice were injected with 200 microliters of the cell suspension at a site on the lateral dorsal area. The sizes of the subsequent subcutaneous abscesses were measured with a caliper gauge, and the area was expressed in square mm. Mixed infections by P. gingivalis and T.denticola produced larger abscesses than those formed after mono-infections by either P. gingivalis or T.denticola. The abscesses caused by mixed infection reached their maxima on the 6th day and maintained that size for the subsequent 5 days. The delayed type hypersensitivities against extracted antigens of P.gingivalis in mixed infection mice were significantly lower than those in the mono-infected mice. However, the IgG response to sonicated antigen of P.gingivalis did not differ between the two groups. The sizes of the abscesses caused by mixed infections in mice immunized with whole cells of P.gingivalis 16-1 were compared to those caused in sham-immunized mice. The average size of the abscess caused by mixed infection in immunized mice did not differ from that in sham-immunized mice, but many of the abscesses in immunized mice ruptured on the 4th or 5th day, followed by recovery in two weeks. These results suggest that mixed infection with P.gingivalis and T.denticola attenuates protective immune responses.  相似文献   
992.
We propose a new bioartificial liver (BAL) system equipped with a high performance hemodialyzer to act as an immunoisolation device. We discuss the design of the BAL system using a mathematical kinetic model with the experimentally obtained mass-transfer performances of various hemodialyzers. The mass transfer resistances of the hemodialyzers did not adversely influence the ammonia-removal and bioactive-substance-supply performances of the BAL system. A suitable hemodialyzer for the BAL system is available even at present using an engineering design. The remaining problems to be overcome before realizing clinical use of the BAL system are to increase the rate constant of the first order reaction of the BAL for ammonia metabolism and to develop a new method of blood access that can be used safely with long term reliability at a high blood flow rate (ca. 556 ml/min).  相似文献   
993.
Background Obstructive vascular lesions at the terminal portion of the internal carotid arteries are thought to be the primary and essential lesions in moyamoya disease. The etiology remains unknown. To detect possible mediators of the thickened intima of moyamoya disease, we measured serum alpha-1-antitrypsin (1-AT) levels and characterized the phenotype of patients with familial moyamoya disease.Patients and methods Fifty-six individuals were examined, including 29 patients with moyamoya disease from 14 families. Serum 1-AT levels were analyzed by electroimmunoassay and genomic phenotype by isoelectric focusing.Results All individuals had a normal 1-AT phenotype. The average serum 1-AT level in moyamoya disease patients was significantly higher than that of normal individuals, although both were within the normal range.Conclusions These findings suggest that serum 1-AT level may be a marker, rather than an etiologic factor, indicating the progression of moyamoya disease.  相似文献   
994.
Drug resistance trends were investigated for 271 Vibrio cholerae O1 (V.c O1) and 401 V. cholerae non-O1 (V.c non-O1) strains isolated from mainly imported diarrheal cases during 1981-2001 in Japan. The results of drug resistance test using 8 drugs (CP, TC, SM, KM, ABPC, ST, NA, and NFLX) showed that 34.7% of the V. c O1 strains and 15.7% of V.c non-O1 strains were multi-drug or mono-drug resistant. The incidence of drug resistant strains has increased since 1991, and it has been remarkable in V.c O1 strains that increased from 1.2% in 1981-1985 to 70.8% in 1996-2001. The drug resistance patterns of the resistant strains classified into 6 types in V.c O1 and 21 types in V.c non-O1. The prevalent patterns recognized were SM (75.5%), CP.TC.SM.ST (10.6%) and CP.SM.ST (8.5%) in V.c O1, and SM (25.4%) and ABPC (25.4%) in V.c non-O1. Ten V.c O1 strains (3.7%) and 10 V.c non-O1 strains (2.5%) were multi-drug resistant including TC. Among those, 13 strains were isolated from travelers who returned to Japan from Thailand. One V.c O1 strain (0.4%) and 6 V.c non-O1 strains (1.5%) were NA high-resistant and fluoroquinolones low-sensitive. Among those, 4 strains were isolated from travelers who returned to Japan from India.  相似文献   
995.
A solitary cutaneous or subcutaneous mass in lymphoblastic lymphoma (LBL) is a rare manifestation. A 15-year-old girl presented with a subcutaneous LBL on her left back. There were no other lesions. Complete remission (CR) was achieved after 2 courses of ACOMP-B (doxorubicin, cyclophosphamide, vincristine, methotrexate, prednisolone, and bleomycin) therapy. Two courses of the chemotherapy and 4 sessions of prophylactic intrathecal methotrexate (15 mg/body) and hydrocortisone (25 mg/body) were added after CR. However, the patient relapsed with bone marrow involvement after 14 months remission. It is necessary to accumulate more experience with this kind of case to find the appropriate treatment strategy for solitary cutaneous or subcutaneous LBL.  相似文献   
996.
This study compared the effects of amlodipine and valsartan on the sympathetic nervous system, the renin-angiotensin-aldosterone system, and brain natriuretic peptide, which are considered important parameters of the long-term prognosis. Seventy-three elderly patients, who had received antihypertensive treatment for more than 6 months with amlodipine, participated in this study. They were randomized to the V group (n = 36) and switched to valsartan from amlodipine, or to the A group (n = 37), which continued treatment with amlodipine. The dose of valsartan was set as that which controlled the blood pressure to the same extent as before switching. Blood samples were measured before and after 6 months of therapy. Data were analyzed by two-way analysis of variance with the Newman-Keuls test. In the V group, norepinephrine (from 597.0 +/- 52.9 to 475 +/- 43.8 pg/ml, p < 0.05) and aldosterone (from 74.5 +/- 7.0 to 53.9 +/- 5.3 pg/ml, p < 0.001) were decreased significantly after 6 months, although norepinephrine and aldosterone levels were unchanged in the A group. However, brain natriuretic peptide did not show a difference between the two groups. These findings suggested that valsartan is probably superior to amlodipine with respect to less activation of the sympathetic nervous system and preventing upregulation of the renin-angiotensin-aldosterone system.  相似文献   
997.
998.
PURPOSE: Gemcitabine/carboplatin is active for advanced-stage non-small-cell lung cancer. Although it has a better toxicity profile than gemcitabine/cisplatin, severe thrombocytopenia can be a problem. We conducted a phase II study of gemcitabine/carboplatin on a 21-day schedule with administration of carboplatin delayed until day 8, intending to decrease the severity of thrombocytopenia and evaluate the feasibility and efficacy of this schedule. PATIENTS AND METHODS: Thirty-one patients with stage IIIB or stage IV non-small cell lung cancer received gemcitabine 1000 mg/m(2) on days 1 and 8 and carboplatin at an area under the curve of 5 mg capital ZE, Cyrillic minute/mL on day 8, every 21 days. RESULTS: The response rate was 22.6%, including 1 complete response. The median time to progression was 161 days, and the median survival was 454 days. Grade 3/4 thrombocytopenia, according to the National Cancer Institute Common Toxicity Criteria, version 3.0, was observed in 2 patients (6.5%) in the first 2 cycles. Nonhematologic toxicity included rash, depression, fever, nausea/vomiting and increased hepatic transaminase. The median courses of delivery were 3, and 13 patients (42%) received the first 3 courses without treatment delay. Dose intensity for each drug was 638 mg/m(2) per week for gemcitabine and 1.56 mg capital ZE, Cyrillic minute/mL per week for carboplatin area under the curve, respectively. CONCLUSION: This study suggests that gemcitabine/carboplatin with a day-8 administration of carboplatin in a 21-day schedule reduces the severity of thrombocytopenia without having a detrimental effect on efficacy.  相似文献   
999.
AIMS: To assess the changes in macular and peripapillary retinal nerve fibre layer (RNFL) thickness in eyes with unilateral optic atrophy and to evaluate the relationship between retinal thickness and visual function. METHODS: Enrolled were 22 patients with unilateral optic atrophy. Macular thickness at the divided nine areas and peripapillary RNFL thickness in quadrantic sections were measured by optical coherence tomography. Thickness values in the affected eyes were compared with those in the contralateral unaffected eyes. The correlation of foveal thickness with best-corrected visual acuity (BCVA) was evaluated. The correlation between retinal thickness and the remaining visual field area circumscribed with I-4-e isopter in superior and inferior hemifield was assessed. RESULTS: Macular thinning was observed in all areas (P < 0.001 in each area) other than the fovea (P = 0.068). Peripapillary RNFL thickness decreased in all quadrantic sections (P < 0.001 in each section). The affected to unaffected eye ratio of retinal thickness was more than 0.6 in each area. BCVA did not correlate with foveal thickness (correlation coefficient = 0.094, P = 0.668). Although not statistically significant (P = 0.281, superior hemifield; P = 0.053, inferior hemifield), there was a tendency that eyes with severe visual field loss show more marked retinal thinning. CONCLUSIONS: Macular thinning with the preserved foveal thickness is a hallmark of eyes with optic atrophy. Together with no correlation between foveal thickness and BCVA, this finding would help in differential diagnosis of macular and optic nerve diseases.  相似文献   
1000.
The authors present a female patient of type-IV laryngo-tracheo-esophageal cleft (LTEC) who survived the definitive operation and was discharged from the hospital. Separation of the trachea and the esophagus was very difficult because they formed almost cylindrical common channel and multiple fistulae occurred after the operation. After multiple attempts of closure of the fistulae, one fistula near the carina remained, and the esophagus was reconstructed using interposed jejunum leaving some part of the esophagus connected to the fistula. Now she is practicing oral feeding. This is the fourth long-term survivor of type-IV LTEC in the international literature.  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