全文获取类型
收费全文 | 46759篇 |
免费 | 4448篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 293篇 |
儿科学 | 1497篇 |
妇产科学 | 1325篇 |
基础医学 | 6365篇 |
口腔科学 | 835篇 |
临床医学 | 6327篇 |
内科学 | 8107篇 |
皮肤病学 | 707篇 |
神经病学 | 4216篇 |
特种医学 | 1673篇 |
外国民族医学 | 3篇 |
外科学 | 5577篇 |
综合类 | 975篇 |
一般理论 | 66篇 |
预防医学 | 5717篇 |
眼科学 | 1155篇 |
药学 | 3390篇 |
2篇 | |
中国医学 | 52篇 |
肿瘤学 | 2970篇 |
出版年
2022年 | 395篇 |
2021年 | 818篇 |
2020年 | 463篇 |
2019年 | 794篇 |
2018年 | 852篇 |
2017年 | 665篇 |
2016年 | 708篇 |
2015年 | 769篇 |
2014年 | 1071篇 |
2013年 | 1698篇 |
2012年 | 2386篇 |
2011年 | 2469篇 |
2010年 | 1395篇 |
2009年 | 1283篇 |
2008年 | 2244篇 |
2007年 | 2329篇 |
2006年 | 2392篇 |
2005年 | 2307篇 |
2004年 | 2320篇 |
2003年 | 2170篇 |
2002年 | 2012篇 |
2001年 | 1349篇 |
2000年 | 1309篇 |
1999年 | 1161篇 |
1998年 | 571篇 |
1997年 | 504篇 |
1996年 | 449篇 |
1995年 | 400篇 |
1994年 | 401篇 |
1993年 | 398篇 |
1992年 | 912篇 |
1991年 | 849篇 |
1990年 | 843篇 |
1989年 | 729篇 |
1988年 | 748篇 |
1987年 | 708篇 |
1986年 | 672篇 |
1985年 | 718篇 |
1984年 | 598篇 |
1983年 | 483篇 |
1982年 | 318篇 |
1981年 | 342篇 |
1980年 | 321篇 |
1979年 | 501篇 |
1978年 | 385篇 |
1977年 | 292篇 |
1976年 | 300篇 |
1974年 | 313篇 |
1973年 | 296篇 |
1972年 | 293篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
81.
Immunohistochemical study of the local inflammatory response to chlamydial ocular infection 总被引:6,自引:0,他引:6
J A Whittum-Hudson H R Taylor M Farazdaghi R A Prendergast 《Investigative ophthalmology & visual science》1986,27(1):64-69
Immunohistochemical staining of conjunctival biopsies from cynomolgus monkeys (Macaca fascicularis) was performed after they received a single primary ocular infection, a single secondary challenge infection, or repeated ocular inoculations with Chlamydia trachomatis. T cells of the suppressor/cytotoxic (OKT8F) phenotype predominated regardless of the infection protocol, and perifollicular T lymphocytes of both the suppressor/cytotoxic and helper (OKT4A) phenotypes appeared in large numbers during the peak inflammatory reaction. In repeatedly inoculated monkeys, T cells and follicles persisted until cessation of reinfection. IgM-bearing B lymphocytes comprised the majority of cells within follicles, with smaller numbers of IgG- or IgA-positive B cells. The major difference in the response to the various infection protocols was the increased number and persistence of follicles with repeated reinoculation. The finding of large numbers of T-suppressor/cytotoxic and T-helper cells in the infected conjunctiva supports a role for cell-mediated immunity in the local response to C. trachomatis ocular infection. 相似文献
82.
83.
To assess the magnitude and nature of interpersonal violence resulting in hospitalisation of children and to identify subgroups at risk of repeat hospital admissions, a population-based, retrospective study of all violence hospitalisations in Western Australia for children aged 9 years or less was undertaken, using the 1990–2004 linked data retrieved from the Western Australian Mortality Database and the Hospital Morbidity Data System.
Of the 747 patients aged <10 years incurring 834 hospitalisations for the consequences of violence during the study period, 570 (76%) were less than 4 years of age. A total of 43 deaths from violence were recorded and 74 (9%) patients were admitted for more than one episode of violence. Victims aged 0–4 years from rural (hazard ratio [HR] = 2.72; 95% confidence interval [CI] 1.35, 5.43) and remote parts (HR = 2.79; 95% CI 1.25, 6.25) of the state were at increased risk of a subsequent admission for violence compared with those residing within the metropolitan area. Indigenous children aged 5–9 years were significantly more likely (HR = 3.57; 95% CI 1.14, 11.13) to incur a second hospitalisation for violence than their non-Indigenous counterparts. The identification of young victim subgroups at high risk of repeat hospitalisations is important for developing intervention strategies to reduce the burden of interpersonal violence. Young children aged 0–4 years living in rural and remote locations and Indigenous children aged 5–9 years should be specifically targeted for attention. 相似文献
Of the 747 patients aged <10 years incurring 834 hospitalisations for the consequences of violence during the study period, 570 (76%) were less than 4 years of age. A total of 43 deaths from violence were recorded and 74 (9%) patients were admitted for more than one episode of violence. Victims aged 0–4 years from rural (hazard ratio [HR] = 2.72; 95% confidence interval [CI] 1.35, 5.43) and remote parts (HR = 2.79; 95% CI 1.25, 6.25) of the state were at increased risk of a subsequent admission for violence compared with those residing within the metropolitan area. Indigenous children aged 5–9 years were significantly more likely (HR = 3.57; 95% CI 1.14, 11.13) to incur a second hospitalisation for violence than their non-Indigenous counterparts. The identification of young victim subgroups at high risk of repeat hospitalisations is important for developing intervention strategies to reduce the burden of interpersonal violence. Young children aged 0–4 years living in rural and remote locations and Indigenous children aged 5–9 years should be specifically targeted for attention. 相似文献
84.
85.
Digital nerve injuries in the hand are common and can result in significant impairment and functional restriction. Despite this, there is relatively little literature, particularly with respect to postoperative rehabilitation. Splinting after repair, purported to protect the repaired nerve from excessive stretch is still commonly used. Recent cadaveric studies indicate postoperative rehabilitation is not necessary with resection up to 2.5mm. A randomized controlled trial was therefore undertaken to determine whether splinting after isolated 5th degree digital nerve transection is in fact necessary. Twenty-six subjects were recruited over a two-year period and randomized to either three weeks of hand-based splinting or free active motion. ANCOVA indicated no differences in sensibility at six months between the two groups. Subjects also reported their greatest functional limitations were because of hyperesthesia. Although this study is underpowered, these limited results suggest splinting may not be required postoperatively. 相似文献
86.
Cora E Lewis Susan K Ewing Brent C Taylor James M Shikany Howard A Fink Kristine E Ensrud Elizabeth Barrett-Connor Steven R Cummings Eric Orwoll 《Journal of bone and mineral research》2007,22(2):211-219
We examined determinants of nonvertebral fracture in elderly men from six U.S. communities followed an average of 4.1 years. Six clinical risk factors predicted fracture risk independent of hip BMD: tricyclic antidepressant use, previous fracture, inability to complete a narrow walk trial, falls in previous year, age > or =80 years, and depressed mood. INTRODUCTION: There are few prospective studies of fracture determinants in men. We examined the associations between a comprehensive set of clinical risk factors and risk of nonspine fracture in older men and whether determinants of fracture risk were independent of total hip BMD. MATERIALS AND METHODS: A total of 5995 men > or =65 years of age were recruited from six communities in the Unites States and followed prospectively for an average of 4.1 years. Baseline assessments of demographic, lifestyle, medical history, functional status, anthropometry, and cognitive, visual, and neuromuscular function were assessed by questionnaire or examination. Triannual mailed questionnaires ascertained incident fracture; reported fractures were adjudicated by physicians using medical records and X-ray reports. Proportional hazards models were used to develop multivariable models, selecting variables and controlling for BMD. RESULTS: Of 5876 men, 4.7% (N = 275) reported an incident nonspine fracture during follow-up (11.46/1000 person-years). Tricyclic antidepressant use (hazard ratio [HR], 2.36; 95% CI, 1.25-4.46), history of fracture at or after age 50 (HR, 2.07; 95% CI, 1.62-2.65), inability to complete a narrow walk trial (HR, 1.70; 95% CI, 1.23-2.34), falls in previous year (HR, 1.59; 95% CI, 1.23-2.05), age > or =80 years (HR, 1.33; 95% CI, 1.01-1.76), depressed mood (HR, 1.72; 95% CI, 1.00-2.95), and decreased total hip BMD (HR, 1.53; 95% CI, 1.34-1.74) were independently related to increased risk. Compared with having none (48.0% of men), having three or more of the clinical risk factors (4.9% of men) increased fracture risk 5-fold, independent of BMD. Having three or more risk factors and being in the lowest tertile of BMD was associated with a 15-fold greater risk than having no risk factors and being in the highest BMD tertile. CONCLUSIONS: Several clinical risk factors were independently associated with nonspine fractures in elderly men. The combination of multiple risk factors and low BMD was a very powerful indicator of fracture risk. 相似文献
87.
OBJECTIVE: To continue surveillance of hormone therapy (HT) use in an Australian population and to assess the impact of the Women's Health Initiative (WHI) and associated reports on HT use 16 months after the results of the WHI were first reported. METHODS: Data were obtained from the 2003 South Australian Health Omnibus Survey, which involves a representative, population face-to-face interview survey. Data were compared to five surveys undertaken between 1991 and 2000, which had consistent methods and quality-control procedures. A total of 907 interviews were conducted with women over 40 years in their own homes by trained health interviewers. RESULTS: In association with the timing of media reporting of the WHI, current HT use rates dropped from 28% in women over 50 years in 2000 to an estimated 10.2% in 2002. By October 2003, current use rates had returned to 18.8% in this age group. The media had been the main influence in the women's decision-making. Half of those who restarted therapy changed to another type of HT. Only 2.8% changed to an alternative/complementary therapy. CONCLUSIONS: Nearly two-thirds (64%) of those currently using HT in 2002 stopped therapy, mostly in response to the media reporting of the WHI. Nearly half of those who stopped HT in 2002 have since restarted. Media reporting greatly influences the use of hormonal therapies. 相似文献
88.
89.
90.
Ganapathy A Prasad Kenneth K Wang Lori S Lutzke Jason T Lewis Schuyler O Sanderson Navtej S Buttar Louis M Wong Kee Song Lynn S Borkenhagen Lawrence J Burgart 《Clinical gastroenterology and hepatology》2006,4(2):173-178
BACKGROUND & AIMS: The aim of this study was to assess the validity of frozen section analysis of endoscopic mucosal resection (EMR) specimens from Barrett's esophagus as compared with permanent sections for the detection of neoplasia. Frozen sections help to give immediate feedback for surgical procedures. It has not been determined whether EMR can be adequately interpreted by using frozen sections to aid endoscopists in completely resecting neoplastic lesions. METHODS: EMR specimens from Barrett's esophagus with high-grade dysplasia (HGD) and/or carcinoma were tested by frozen section. Pathologists evaluated EMR specimens for the depth of invasion as well as the appearance of clear margins of resection. The kappa statistic was calculated to assess the degree of agreement between the frozen section and permanent section diagnoses. RESULTS: Twenty-three consecutive patients underwent 30 EMRs with frozen section diagnosis. Frozen section revealed a carcinoma in 7 specimens (23%) and dysplasia in 20 (66%). Permanent sections found carcinoma in 8 specimens (26%), dysplasia in 19 specimens (63%), and normal or nondysplastic Barrett's esophagus in the remainder. The kappa statistic for the depth of invasion of EMR specimens was 0.93 (near perfect agreement). The kappa statistic for the margins of the EMR specimens was 0.80 (excellent agreement). CONCLUSIONS: This study indicated that frozen section analysis of esophageal EMR specimens is valid as compared with permanent section. This technique might allow rapid evaluation about the degree and depth of involvement of cancers. This allows physicians to make decisions regarding further therapy if margins are involved or decrease the use of EMR for histologically benign-appearing lesions. 相似文献