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   1584篇
  免费   57篇
  国内免费   12篇
耳鼻咽喉   13篇
儿科学   52篇
妇产科学   36篇
基础医学   150篇
口腔科学   18篇
临床医学   239篇
内科学   249篇
皮肤病学   57篇
神经病学   139篇
特种医学   169篇
外科学   116篇
综合类   53篇
一般理论   1篇
预防医学   155篇
眼科学   37篇
药学   69篇
中国医学   5篇
肿瘤学   95篇
  2022年   21篇
  2021年   32篇
  2020年   22篇
  2019年   35篇
  2018年   21篇
  2017年   25篇
  2016年   29篇
  2015年   36篇
  2014年   57篇
  2013年   68篇
  2012年   78篇
  2011年   87篇
  2010年   67篇
  2009年   43篇
  2008年   81篇
  2007年   89篇
  2006年   80篇
  2005年   86篇
  2004年   78篇
  2003年   73篇
  2002年   53篇
  2001年   28篇
  2000年   21篇
  1999年   27篇
  1998年   34篇
  1997年   31篇
  1996年   27篇
  1995年   22篇
  1994年   22篇
  1993年   12篇
  1992年   13篇
  1991年   11篇
  1990年   18篇
  1989年   32篇
  1988年   17篇
  1987年   21篇
  1986年   24篇
  1985年   27篇
  1984年   15篇
  1983年   7篇
  1982年   7篇
  1981年   5篇
  1980年   5篇
  1978年   5篇
  1977年   5篇
  1976年   5篇
  1975年   7篇
  1973年   4篇
  1972年   4篇
  1968年   5篇
排序方式: 共有1653条查询结果,搜索用时 15 毫秒
91.
With changes in livestock management practices and food processing industry, along with changes in people's food habits, many diseases have emerged. Infection with verotoxin-producing Escherichia coli (VTEC) is one such illness. In the present study an attempt was made to isolate, identify and characterize VTEC strains with reference to the O157:H7 serotype from animal, human sources and some food products with the aid of the available modern methods. A total of 876 samples (330 animal, 184 human, 362 food samples) were screened for the presence of VTEC by conventional as well as PCR technique. Seventeen VTEC strains (12 animal, one human and four food samples) were isolated. The isolation rate was higher in diarrhoeic animals (6.02%), followed by diarrhoeic handler (3.12%) and raw beef (1.78%) samples. All strains showed the presence of the VT gene by PCR tests and were uniformly sensitive to common antibiotics except tetracycline, cephalexin, dicloxacillin, erythromycin and lincomycin. Since all strains were isolated from various sources of animal and human origin and all strains showed the presence of the VT gene and uniform antibiogram, a zoonotic association is suggested. This study marks the first report of isolation of VTEC strains from animal sources in India.  相似文献   
92.

Background

Multiple myeloma (MM) is a hematologic malignancy of plasma cell origin. MM primarily affects bone marrow, but extramedullary sites can also be involved. Myelomatous pleural effusion (MPE) is an atypical and rare complication of MM. We aimed to systematically study the incidence and clinicopathologic profile of patients with MPE in a real-world setting.

Patients and Methods

In this retrospective study, 415 consecutive patients with MM managed at a tertiary care center in North India during a study period of January 1, 2010 to December 31, 2015 were evaluated for MPE. The patients with MPE were analyzed for their clinical profile, diagnosis, treatment, and outcomes.

Results

Of these 415 patients, 11 (2.65%) patients had MPE. The median age of the study population was 50 years with male preponderance. The majority of these patients had immunoglobin (Ig)G Kappa disease. All patients had higher than International Staging System stage I disease. MPE was a presenting feature at MM diagnosis in 45.45% (n = 5) of the patients, whereas the rest developed MPE during follow-up. MPE presented predominantly (81.8%) as a unilateral effusion. Concurrent extramedullary involvement at other site was seen in 45.45% (n = 5), with 3 (27%) patients having concurrent myelomatous ascites. Six of these were managed aggressively, whereas 5 patients opted for palliation. The outcomes were dismal (90.9% mortality), with a median survival of 2.47 months.

Conclusion

MPE is a rare entity, and positive outcomes of therapy remain low with dismal prognosis.  相似文献   
93.
In a case-control study to understand the risk factors for development of life-threatening dehydration, a total of 379 children comprising 243 cases (moderate or severe dehydration) and 136 controls (non or mild dehydration) up to 2 years of age suffering from acute watery diarrhoea were studied. By univariate analysis, the presence of vibrios in stool, withdrawal of breast feeding during diarrhoea, not giving fluids, including oral rehydration solution (ORS), during diarrhoea, frequent purging (> 8/ day), vomiting (> 2/day) and undernutrition were identified as risk factors. However, by multivariate analysis after controlling for confounders, withdrawal of breast feeding during diarrhoea (odds ratio (OR) = 6.8, p < 0.00001) and not giving ORS during diarrhoea (OR = 2.1, p < 0.006) were identified as significant risk factors. The confounding variables which also contributed significantly to increasing the risk were age (≤ 12 months; OR = 2.7, p = 0.001), frequent purging (> 8/day; OR = 4.1, p < 0.00001), vomiting (> 2/day; OR = 2.4, p = 0.001) and severe undernutrition (%median <60 weight-for-age of Indian Academy of Paediatrics classification; OR = 3.1, p = 0.001). We feel that these findings will be useful for Global and National Diarrhoeal Diseases Control Programmes for formulating intervention strategies for preventing death due to diarrhoeal dehydration.  相似文献   
94.
Aims: The aims of this study were to evaluate patterns of handgrip (HG) strength in relation to gender and age in English schoolchildren and to compare this with existing data and produce reference data for this population. Methods: The HG of 7147 English schoolchildren (3773 boys and 3374 girls) aged 10–15.9 years was measured using a portable Takei handgrip dynamometer (Takei Scientific Instruments Co. Ltd, Tokyo, Japan). Centile data were produced using the Generalized Additive Models for Location, Scale and Shape. Z‐scores were generated using existing data for European children. Age and gender interactions were analysed using analysis of covariance. Results: In boys and girls, significant increases in HG were found between every age‐group (p < 0.001). Boys were significantly stronger than girls at every age (p < 0.001) and the boys’ age‐related increase was significantly greater than the girls’ (p < 0.001). Conclusion: This study provides reference data for handgrip strength in English schoolchildren. Handgrip strength in English children is broadly similar to existing European data, after adjusting for mass and stature. These data could be used for clinical or athletic screening of low and high strength in this population.  相似文献   
95.
Background We developed a decision aid for patients with curable prostate cancer based on Svenson’s DiffCon Theory of Decision Making. This study was designed to determine if surrogate patients using the aid could understand the information presented, complete all tasks, show evidence of differentiation, and arrive at a preferred treatment choice. Methods Men, at least 50 years old and never diagnosed with prostate cancer, were recruited through local advertisements. Participants were asked to imagine that they were a case‐scenario patient. Then they completed the decision aid interview, which included three components: (i) information presentation, with comprehension questions, (ii) exercises to help identify attributes important to the decision, and (iii) value‐clarification exercises. Results Sixty‐nine men volunteered. They had a mean age of 61.2 (range 50–83) years, 37% had no formal education beyond high school, and 87% were living with a partner. All participants completed all aspects of the interview. They answered an average of 10 comprehension questions each, with a mean of 94.7% correct without a prompt. Each attribute in the information presented was identified by at least one participant as important to his decision. Participants identified a median of five attributes as important (ranges 1–14) at each of three points during the interview; 75% changed at least one important attribute during the interview. Forty‐nine per cent of participants also identified attributes as important that were not included in the presented information. Participants showed a wide range of values in each of seven trade‐off exercises. Eighty‐eight per cent of participants showed evidence of differentiation; 75% had a clear treatment preference by the end of the interview. Conclusions Our decision aid appears to meet its goals for surrogate patients and illustrates the strengths of the DiffCon theory. The ability of the aid to accommodate wide variability, both in information needs and in important attributes, is a particular strength of the decision aid. It now requires testing in patients with prostate cancer.  相似文献   
96.
Traumatic brain injury poses significant and diverse challenges to rehabilitation efforts. Neurobehavioural deficits represent a particularly difficult barrier to rehabilitative progress and societal reintegration. Early studies have identified dopaminergic drugs such as amantadine, bromocriptine and sinemet as potentially assistive in countering these deficits. To date, side effect profiles have been relatively benign, noted most frequently in small scale case trials. The case of a 40 year old patient with bilateral frontal traumatic brain injuries, and previous arteriovenous malformation AVM bleed with significant ataxia, dysarthria and neurobehavioural deficits is presented. This long range study demonstrates, through multiple varied dosing schedules, a trade off between the benefits and side effects of dopaminergic therapy, with implications for a larger brain injury population.  相似文献   
97.
98.
Dershaw  DD; Shank  B; Reisinger  S 《Radiology》1987,164(2):455-461
Following local excision and definitive irradiation of 163 breast cancers in 160 women, alterations in mammographic patterns were observed for up to 7 years. Skin thickening was observed in 96% of mammograms obtained within 1 year of completing therapy and was most pronounced in women treated with iridium implant, chemotherapy, or axillary dissection. In 76% of mammograms, alterations in the parenchymal pattern, including coarsening of stroma and increased breast density, were seen at 1 year. Neither skin nor parenchymal changes progressed after 1 year. Within 3 years of treatment the parenchymal density, which usually regressed, did not change in all patients. At 3 years skin thickness and the parenchymal pattern had returned to normal in less than 50% of the breasts of these women. Scars developed in approximately one-quarter of women. They were present on the initial post-treatment mammogram and remained unchanged on serial studies. Coarse, benign calcifications also developed in the breasts of about one-quarter of women. Microcalcifications developed in 11 breasts; biopsy specimens of six were benign. Benign microcalcifications may be related to therapy.  相似文献   
99.
Liver metastases: detection by phase-contrast MR imaging   总被引:1,自引:0,他引:1  
Stark  DD; Wittenberg  J; Middleton  MS; Ferrucci  JT  Jr 《Radiology》1986,158(2):327-332
Forty patients with biopsy-proved metastatic liver cancers were studied by magnetic resonance (MR) imaging using one or more conventional (in-phase) pulse sequences and a corresponding phase-contrast (opposed-phase) pulse sequence. Pulse-sequence performance was quantitated by measuring signal-difference-to-noise (SD/N) ratios between cancerous tissue and liver. The SD/N performance of T2-weighted spin-echo (SE) pulse sequences improved when used with the phase-contrast technique. SE 2,000/30 opposed-phase images showed improved (P less than .001) SD/N in 72% of patients over in-phase images. The SD/N of T1-weighted SE or inversion recovery pulse sequences deteriorated when used with the phase-contrast technique. Changes in measured SD/N correlated well with image appearance and actual lesion detectability in individual cases. Phase-contrast imaging should be employed routinely when T2-weighted SE pulse sequences are relied on to detect liver cancer.  相似文献   
100.
Between December 1986 and October 1988, 83 patients with chronic peripheral artery occlusions were treated with a new technique. In 56 patients, the superficial femoral artery was completely occluded; in 21 patients, the popliteal artery; and in six patients, the iliac artery. The length of occlusion ranged from 5 to 35 cm (mean, 12.5 cm). The duration, estimated by history, was 5-48 months (mean, 16.5 months). In seven patients, durations of 6-36 months were documented angiographically. A flexible, blunt, motor-driven rotating catheter was introduced through an 8-F sheath, and rotational angioplasty was performed at low speed (up to 200 rpm). In 49 of 60 (82%) patients in whom this new technique was used as the primary intervention, the occlusions were successfully reopened. In 23 patients in whom conventional methods had failed more than 4 weeks earlier, the success rate for rotational angioplasty was 67% (12 of 18 patients); when the time interval was less than 4 weeks, only one of five patients was treated successfully. In none of the 83 patients did a perforation occur. This new technique can reopen chronic artery occlusions with a high degree of success and without the danger of vessel-wall perforation, even after failure of conventional techniques.  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