全文获取类型
收费全文 | 36448篇 |
免费 | 2306篇 |
国内免费 | 174篇 |
专业分类
耳鼻咽喉 | 400篇 |
儿科学 | 951篇 |
妇产科学 | 837篇 |
基础医学 | 5174篇 |
口腔科学 | 581篇 |
临床医学 | 4868篇 |
内科学 | 6364篇 |
皮肤病学 | 750篇 |
神经病学 | 3522篇 |
特种医学 | 1163篇 |
外科学 | 3610篇 |
综合类 | 312篇 |
一般理论 | 66篇 |
预防医学 | 4135篇 |
眼科学 | 612篇 |
药学 | 2673篇 |
1篇 | |
中国医学 | 177篇 |
肿瘤学 | 2732篇 |
出版年
2023年 | 173篇 |
2022年 | 448篇 |
2021年 | 901篇 |
2020年 | 490篇 |
2019年 | 757篇 |
2018年 | 906篇 |
2017年 | 703篇 |
2016年 | 827篇 |
2015年 | 995篇 |
2014年 | 1425篇 |
2013年 | 1966篇 |
2012年 | 2830篇 |
2011年 | 2846篇 |
2010年 | 1636篇 |
2009年 | 1414篇 |
2008年 | 2461篇 |
2007年 | 2543篇 |
2006年 | 2441篇 |
2005年 | 2394篇 |
2004年 | 2205篇 |
2003年 | 2050篇 |
2002年 | 1851篇 |
2001年 | 390篇 |
2000年 | 307篇 |
1999年 | 363篇 |
1998年 | 394篇 |
1997年 | 284篇 |
1996年 | 265篇 |
1995年 | 249篇 |
1994年 | 209篇 |
1993年 | 198篇 |
1992年 | 149篇 |
1991年 | 135篇 |
1990年 | 114篇 |
1989年 | 117篇 |
1988年 | 96篇 |
1987年 | 90篇 |
1986年 | 84篇 |
1985年 | 91篇 |
1984年 | 124篇 |
1983年 | 117篇 |
1982年 | 138篇 |
1981年 | 125篇 |
1980年 | 114篇 |
1979年 | 65篇 |
1978年 | 69篇 |
1977年 | 68篇 |
1976年 | 52篇 |
1975年 | 43篇 |
1974年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Pancreatoblastoma has been described in children and characterized by unique histologic features and excellent clinical course. Ultrastructural and immunohistochemical studies of pancreatoblastoma reveal either exocrine alone or both endocrine and exocrine differentiation. We present two cases of pancreatoblastoma in children in which immunohistochemical and ultrastructural examination failed to demonstrate features of either enzyme or hormone production and which became worse in clinical course. We assume that pancreatoblastomas are tumors which differentiate more toward acinar or ductal elements than toward islet cell. 相似文献
82.
Drinking History Is Related to Persistent Blood Pressure Dysregulation in Postwithdrawal Alcoholics 总被引:1,自引:1,他引:0
Andrea C. King Oscar A. Parsons Nancy C. Bernardy William R. Lovallo 《Alcoholism, clinical and experimental research》1994,18(5):1172-1176
We have previously demonstrated that alcoholics with transitory (< 72 hr) elevations in blood pressure (BP) during withdrawal continue to show residual cardiovascular dysregulation up to 4 weeks of abstinence. The present study replicates and extends these findings. Alcoholic inpatients were divided into three subgroups ( ns = 14) based on BP during the first 72 hr of withdrawal: transitory hypertensives (tHTs; BP > 160/95 mm Hg), transitory borderline hypertensives (tBHs; 140/90 BP < 160/95), and normotensives (NTs; all BPs < 140/90). All patients had normal resting pressures after 72 hr of withdrawal. At 3–4 weeks postadmission, the alcoholics and 14 nonalcoholic controls (CONTs) were tested at rest and during a 5-min handgrip task. The tHTs showed an exaggerated systolic and diastolic BP response to handgrip compared with NTs and CONTs, with tBHs intermediate ( ps < 0.05). Drinking history showed the tHTs had the highest reported level of alcohol consumption and severity of withdrawal symptoms ( ps < 0.05). Regression analyses indicated that consumption of hard liquor was the variable most predictive of admission BPs; further, parental history of hypertension potentiated this relationship for systolic BP. Age and consumption of nicotine and caffeine were not significant predictors of admission BP. The results suggest a persistent cardiovascular dysregulation in alcoholics showing transient hypertensive withdrawal BPs. These alcoholics may be at increased risk for future alcohol-related cardiovascular disorder. 相似文献
83.
84.
85.
Nurses need to take advantage of multiple internships and fellowships to learn about and experience the daily work of making health policy in Washington, DC. This article lists several of the current programs available for nurses and other health professionals. These internships and fellowships are career-changing experiences. Additionally, new relationships will be built with other health professionals that nurses will be able to use for years to come. Finally, if one of the structured experiences doesn't fit the nurse's timeframe, there is always the possibility to create a special internship to meet the nurse's needs. 相似文献
86.
87.
BACKGROUND: Numerous preclinical and clinical studies have reported on the use of platelet concentrates to promote tissue healing. The results in spinal fusion applications are limited and controversial. PURPOSE: The purpose of the current prospective clinical cohort study is to assess the effect of Autologous Growth Factors (AGF) on lumbar interbody fusion with specific attention paid to determination of clinical and radiographic outcomes. STUDY DESIGN/SETTING: Prospective clinical study PATIENT SAMPLE: Candidates for anterior-posterior lumbar fusion with diagnosis of degenerative disc disease and/or up to grade I spondylolytic spondylolisthesis based on positive provocative discography. OUTCOME MEASURES: Clinical (visual analogue pain scale/functional outcome assessment) and radiographic outcomes (fusion on computed tomography at 6 months and plain radiographs at 12 and 24 months). METHODS: Thirty-seven patients were assigned to standard anterior-posterior interbody fusion L2-S1 (single or two-level) using iliac crest bone graft (autograft group: 22 patients with 32 levels operated) or allograft combined with autogenous growth factors (AGF group: 15 patients with 25 levels operated). Radiographic outcomes were collected at 6 months postsurgery with computed tomography and at 12 and 24 months with plain radiographs. Pre- and postoperative clinical outcome measures included visual analog scores (VAS) for back and leg pain (0-10), SF-36 scores, and Oswestry disability determination. Average clinical and radiographic follow-up for the autograft group was 24.3+/-5.6 months (12-36 months) and AGF was 25.7+/-7.5 (6-40 months). RESULTS: Fusion incorporation at each end plate was determined at 56% in both autograft and AGF (p=NS) patients based on computed tomography at 6 months with minimal subsidence noted and no direct correlation between the incidence or degree of cage subsidence and bone graft technique. The 12- and 24-month radiographic results confirmed an 85% arthrodesis rate for the autograft patients, whereas the AGF patients had an 89% fusion rate (p=NS). Clinical outcomes were similar for both groups and no significant differences were noted for pain or functional outcome improvements. CONCLUSIONS: AGF combined with an allograft carrier is equivalent in radiographic and clinical outcomes to autograft in one- or two-level lumbar interbody fusion with supplemental posterior fixation and, thus, eliminates any morbidity from iliac crest bone graft harvesting. AGF combined with an appropriate carrier is a reasonable alternative to autograft and expensive bone induction technologies. Further research is still required to examine the optimum carriers, preparation and formulation, and platelet concentrations for this technology. 相似文献
88.
89.
Nancy I Thomas Norman DePaul Brown Linda C Hodges Jay Gandy Louanne Lawson Janet E Lord David K Williams 《AAOHN journal》2006,54(1):24-31
The Central Arkansas Veterans Healthcare System (CAVHS) spends $1 million annually on occupational illnesses and injuries. To address the problem of injuries among hospital employees, a retrospective case-control study was conducted to examine select risk factors for work-related injuries (WRI) among CAVHS employees. Study methods included a review of employee health charts and computer and manual databases from 1997 to 2002 (N = 2,050). The researchers found that WRI increased with age; WRI occurred more often in women than in men; WRI was greater among maintenance and custodial staff compared to direct caregivers, and less among clerical staff; WRI occurred less often in part-time than full-time staff; and WRI increased with increasing body mass index. Developing standards, guidelines, and policies for preplacement screening, preventive measures, training, and education may help to minimize WRI and associated costs. 相似文献
90.
3-Monochloro-1,2-propanediol (MCPD) is a well-known by-product of acid-hydrolyzed soy sauce during its manufacturing process. MCPD has been reported genotoxic in vitro, and reproductive toxicity and carcinogenicity in rats. To evaluate the immunomodulatory effect of MCPD on murine splenocyte and macrophage in vitro, we investigated splenocyte blastogenesis by concanavalin A (Con A), anti-CD3, and lipopolyssacharide (LPS), the production of cytokines from splenocyte, and the activity of mouse peritoneal macrophages. There was a significant decrease in lymphocyte blastogenesis to Con A or anti-CD3 at subtoxic dose of MCPD. A significant decrease in splenocyte blastogenesis to LPS was also observed. The production level of interferon (IFN)-gamma on splenocyte culture with Con A was significantly reduced at the higher concentration than 1.0mM of MCPD. The levels of interleukin (IL)-4 and IL-10 were also decreased at high concentrations of MCPD. There was a significant decrease in production of nitric oxide (NO) by peritoneal macrophages treated with MCPD. MCPD also inhibits tumor necrosis factor (TNF)-alpha production of stimulated macrophages. These results indicate that MCPD might be able to reduce the functionality of lymphocytes and peritoneal macrophages in vitro. 相似文献