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   8436篇
  免费   473篇
  国内免费   20篇
耳鼻咽喉   119篇
儿科学   239篇
妇产科学   157篇
基础医学   1119篇
口腔科学   506篇
临床医学   566篇
内科学   1746篇
皮肤病学   195篇
神经病学   807篇
特种医学   154篇
外科学   1157篇
综合类   35篇
一般理论   5篇
预防医学   909篇
眼科学   147篇
药学   615篇
中国医学   41篇
肿瘤学   412篇
  2023年   79篇
  2022年   82篇
  2021年   189篇
  2020年   127篇
  2019年   182篇
  2018年   316篇
  2017年   243篇
  2016年   220篇
  2015年   319篇
  2014年   330篇
  2013年   465篇
  2012年   722篇
  2011年   803篇
  2010年   334篇
  2009年   273篇
  2008年   578篇
  2007年   528篇
  2006年   451篇
  2005年   491篇
  2004年   423篇
  2003年   337篇
  2002年   279篇
  2001年   161篇
  2000年   145篇
  1999年   134篇
  1998年   37篇
  1997年   18篇
  1996年   16篇
  1995年   16篇
  1994年   20篇
  1993年   14篇
  1992年   55篇
  1991年   56篇
  1990年   43篇
  1989年   45篇
  1988年   44篇
  1987年   36篇
  1986年   33篇
  1985年   26篇
  1984年   23篇
  1983年   16篇
  1978年   12篇
  1974年   16篇
  1973年   12篇
  1972年   17篇
  1971年   12篇
  1970年   12篇
  1969年   16篇
  1967年   16篇
  1966年   12篇
排序方式: 共有8929条查询结果,搜索用时 15 毫秒
1.
2.
Ovarian carcinoma is one of the most lethal malignancies, but only very few prognostic biomarkers are known. The degradome, comprising proteases, protease non-proteolytic homologues and inhibitors, have been involved in the prognosis of many cancer types, including ovarian carcinoma. The prognostic significance of the whole degradome family has not been specifically studied in high-grade serous ovarian cancer. A targeted DNA microarray known as the CLIP-CHIP microarray was used to identify potential prognostic factors in ten high-grade serous ovarian cancer women who had early recurrence (<1.6 years) or late/no recurrence after first line surgery and chemotherapy. In women with early recurrence, we identified seven upregulated genes (TMPRSS4, MASP1/3, SPC18, PSMB1, IGFBP2, CFI – encoding Complement Factor I – and MMP9) and one down-regulated gene (ADAM-10). Using immunohistochemistry, we evaluated the prognostic effect of these 8 candidate genes in an independent cohort of 112 high-grade serous ovarian cancer women. Outcomes were progression, defined according to CA-125 criteria, and death. Multivariate Cox proportional hazard regression models were done to estimate the associations between each protein and each outcome. High ADAM-10 expression (intensity of 2–3) was associated with a lower risk of progression (adjusted hazard ratio (HR): 0.51; 95% confidence interval (CI): 0.29-0.87). High complement factor I expression (intensity 2–3) was associated with a higher risk of progression (adjusted HR: 2.30, 95% CI: 1.17–4.53) and death (adjusted HR: 3.42; 95% CI: 1.72–6.79). Overall, we identified the prognostic value of two proteases, ADAM-10 and complement factor I, for high-grade serous ovarian cancer which could have clinical significance.  相似文献   
3.
4.
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.  相似文献   
5.
A simple tool to evoke physicians' real training needs.   总被引:1,自引:0,他引:1  
Commonly used methods for identifying the training needs of general practitioners do not enable the real needs felt during interviews with patients during office visits to be detected. In this study, the authors evaluate how physicians' use of a personal-office-visit diary affects the level of specificity of their expressed training needs. In 1999, the authors carried out a controlled intervention trial using a random sample of 1,038 general practitioners from a region of France, randomized to intervention and control groups. The practitioners in the intervention group were asked to identify their training needs using a personal-office-visit diary. The level of specificity for their expressed needs was compared with that of the expressed needs of the practitioners in the control group. The use of the diary was associated with a significantly higher level of specificity in the training needs identified by the general practitioners who participated. Independent of the intervention, practitioners under 40 years of age, those in urban practice, and those who were members of a continuing medical education (CME) association expressed their training needs with higher specificity. The personal-office-visit diary would seem to be a simple, inexpensive, and useful tool for more specifically identifying training needs, which could help establish more appropriate and better-targeted training programs. However, it should be assessed further by those involved in CME for general practitioners.  相似文献   
6.
7.
The objective of this study was to determine the presence of different species of the genus Malassezia in the healthy external auditory canal of wild felids maintained in captivity. One hundred and thirty-two adult animals (264 samples of cerumen), 77 males (58.3%) and 55 females (41.7%), were studied: large felids (55 animals) - 26 lions (Panthera leo), 13 tigers (Panthera tigris), 6 leopards (Panthera pardus), 6 jaguars (Panthera onca), 2 cheetahs (Acinonyx jubatus), 2 pumas (Puma concolor); small felids (77 animals) - 29 tiger cats (Leopardus tigrinus), 19 jaguarundis (Herpailurus yagouaroundi), 10 margays (Leopardus wiedii), 9 pampas cats (Oncifelis colocolo), 6 geoffroy's cats (Oncifelis geoffroyi), and 4 servals (Leptailurus serval). Samples were obtained by the introduction of a sterile swab into the ear canal after cleaning the auricle with an alcohol-ether solution. The swabs were seeded onto Petri dishes containing modified Mycosel agar and sterile olive oil was added to the surface of the medium before specimen seeding. The plates were incubated at 35oC for two weeks. The isolates were analyzed regarding macro-and micromorphology and identified through catalase tests and growth on Tween 20, 40, 60 and 80. Malassezia spp. were isolated from 58 of the felids studied (43.9%) and from 102 samples of cerumen (38.6%). Malassezia sympodialis was isolated exclusively in large felids (33 animals-56.9%), and Malassezia pachydermatis exclusively in smaller varieties (25 animals - 43.1%). The incidence of fungi was higher in lions, with yeast being isolated in 25 of 26 animals (96.2%). Forty-eight strains (47.1%) were isolated from the right ear canal and 54 (52.9%) from the left. Although M. pachydermatis is the species considered a member of the microbiota of the mammalian external ear canal these results suggest that M. sympodialis participates in the microbiota of large felids.  相似文献   
8.
ImmunoCyt/uCyt is a fluorescent test combining three monoclonal antibodies. In this study, it has been tested as a complement to cytology in the detection of urothelial carcinoma in urine. It has been performed simultaneously with standard cytology and cystoscopy on 870 urine analyses from one hospital. In 136 cases, one or more bladder tumors were found. Overall sensitivity of cytology, ImmunoCyt/uCyt and combined analyses reached 29, 74 and 84%, respectively, and overall specificity was 98, 62 and 61%. The negative predictive value of cytology, ImmunoCyt/uCyt and both analyses was 88, 93 and 95%, respectively, and the positive predictive value was 70, 26 and 29%. The sensitivity of cytology for low malignant potential neoplasms, low- and high-grade papillary carcinomas was 6, 18 and 53%, while it reached 71, 79 and 93% when combined with ImmunoCyt/uCyt. The sensitivity of cytology for stages Ta, T1, T2 and over and Tis tumors was 12, 67, 47 and 50%, while it reached 78, 83, 79 and 100% when combined with ImmunoCyt/uCyt. In the absence of tumor on cystoscopy but with positive ImmunoCyt/uCyt, 18% of patients developed a tumor, 2-6 months later. Of the 109 cases diagnosed as suspicious for malignancy by cytology, a tumor was present in 30 cases and ImmunoCyt/uCyt was positive in 22 (73%) of them. In conclusion, ImmunoCyt/uCyt may be used to postpone cystoscopies in patients followed for bladder cancer and may help to save cytologist and pathologist screening time.  相似文献   
9.
BACKGROUND: The role of local excision for pT2 distal rectal cancer has been challenged because of the observation of high rates of lymph node metastases and local failure. However, neoadjuvant chemoradiation therapy (CRT) has led to increased local disease control and significant tumor downstaging, possibly decreasing rates of lymph node metastases. In this setting, a possible role for local excision of ypT2 has been suggested. METHODS: A total of 401 patients with distal rectal cancer underwent neoadjuvant CRT. Tumor response assessment was performed after at least 8 weeks from CRT completion. One hundred and twelve patients with complete clinical response were not immediately operated on and were excluded from the study, and 289 patients with incomplete clinical response were managed by radical surgery. Patients with final pathological stage ypT2 were analyzed to determine the risk of unfavorable pathological features that could represent unacceptable risk for local failure after local excision. RESULTS: Eighty-eight (30%) patients had ypT2 rectal cancer. Final ypT status was not associated with pretreatment radiological staging (p = 0.62). ypT status was significantly associated with the risk of lymph node metastases, risk of perineural and vascular invasion, and recurrence (p = 0.001). Lymph node metastases were present in 19% of patients with ypT2 rectal cancer. The risk of lymph node metastases in ypT2 was associated with the presence of perineural invasion (47% vs 4%; p = <0.001), vascular invasion (59% vs 6%; p < 0.001), and decreased mean interval CRT surgery (12 vs 18 weeks; p < 0.001), but not with mean tumor size (3.2 vs 3.1 cm; p = 0.8). Disease-free and overall survival rates were significantly better for patients with ypT2N0 (p = 0.02 and 0.006, respectively). Fifty-five (63%) patients with ypT2 had at least one unfavorable pathological feature for local excision (lymph node metastases, vascular or perineural invasion, mucinous type or tumor size >3 cm). CONCLUSION: Lymph node metastases were present in 19% of patients with ypT2 and were significantly associated with poor overall and disease-free survival rates. The risk of lymph node metastases could not be predicted by radiological staging or tumor size. Radical surgery should be considered the standard treatment option for ypT2 rectal cancer after CRT.  相似文献   
10.
OBJECTIVE: To determine the location in soft tissues of the calcifications, similar to calcified carotid atheromas, that can be observed radiographically in the cervical region in panoramic radiographs. STUDY DESIGN: In each anatomic cadaver specimen preserved in formol, consisting of the head and neck, radiopaque spheres (made from gutta-percha) were positioned in anatomic structures of the cervical region that can be sites of calcification. For each anatomic structure marked in this way, panoramic radiography was performed, consisting of 17 radiographs. The images obtained were analyzed by 24 examiners who indicated which radiographs, in their opinion, presented the radiopaque reference projected in the region of bifurcation of the carotid artery. Analysis of 2 proportions from agreement and disagreement was used to determine radiopacities that could be confused in panoramic radiographs with calcified atheromas in the carotid artery. RESULTS: The results showed that 75% (18) of the examiners correctly indicated the reference in the bifurcation of the carotid artery and 79.2% (19) indicated a triticeous cartilage as calcified atheroma of the carotid artery. CONCLUSIONS: Calcified atheromas of the carotid artery are not the only features that can produce radiopaque images lateral to the panoramic radiograph; the presence of calcification in the triticeous cartilage also can induce an erroneous diagnosis of calcified carotid atheroma.  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