全文获取类型
收费全文 | 22870篇 |
免费 | 1894篇 |
国内免费 | 56篇 |
专业分类
耳鼻咽喉 | 122篇 |
儿科学 | 895篇 |
妇产科学 | 478篇 |
基础医学 | 3414篇 |
口腔科学 | 423篇 |
临床医学 | 2829篇 |
内科学 | 4442篇 |
皮肤病学 | 371篇 |
神经病学 | 2462篇 |
特种医学 | 520篇 |
外科学 | 2376篇 |
综合类 | 341篇 |
一般理论 | 30篇 |
预防医学 | 2509篇 |
眼科学 | 276篇 |
药学 | 1677篇 |
中国医学 | 46篇 |
肿瘤学 | 1609篇 |
出版年
2023年 | 275篇 |
2022年 | 328篇 |
2021年 | 703篇 |
2020年 | 467篇 |
2019年 | 768篇 |
2018年 | 766篇 |
2017年 | 529篇 |
2016年 | 586篇 |
2015年 | 581篇 |
2014年 | 745篇 |
2013年 | 1099篇 |
2012年 | 1646篇 |
2011年 | 1603篇 |
2010年 | 852篇 |
2009年 | 738篇 |
2008年 | 1244篇 |
2007年 | 1243篇 |
2006年 | 1225篇 |
2005年 | 1144篇 |
2004年 | 975篇 |
2003年 | 965篇 |
2002年 | 893篇 |
2001年 | 360篇 |
2000年 | 340篇 |
1999年 | 313篇 |
1998年 | 200篇 |
1997年 | 188篇 |
1996年 | 138篇 |
1995年 | 155篇 |
1994年 | 106篇 |
1993年 | 115篇 |
1992年 | 216篇 |
1991年 | 242篇 |
1990年 | 181篇 |
1989年 | 213篇 |
1988年 | 226篇 |
1987年 | 267篇 |
1986年 | 207篇 |
1985年 | 238篇 |
1984年 | 155篇 |
1983年 | 115篇 |
1982年 | 95篇 |
1981年 | 107篇 |
1980年 | 79篇 |
1979年 | 114篇 |
1978年 | 120篇 |
1977年 | 117篇 |
1976年 | 81篇 |
1975年 | 80篇 |
1974年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Greg Guest Laura Johnson Holly Burke Reathe Rain-Taljaard Lawrence Severy Claire von Mollendorf Lut Van Damme 《AIDS education and prevention》2007,19(4):310-320
If proven effective, vaginal microbicides and diaphragms will likely be part of a larger HIV prevention model that includes condoms and other prevention strategies. It is, therefore, important to understand how introducing new prevention methods may affect overall patterns of sexual risk behavior. Data presented were collected as part of a safety and feasibility study of ACIDFORM gel with a diaphragm among 120 women in South Africa. Interviews were administered at enrollment and months 1, 3, 5, and 6 of the trial. Focus groups were conducted at trial exit. Frequency of sex increased significantly after enrollment. This increase appears to be owing to perceived protection from HIV and greater sexual pleasure afforded by the gel. Male condom use was high overall but increased significantly from enrollment. Data suggest this is because of increased partner involvement, increased negotiating power afforded by study participation, and provision of free condoms perceived to be of high quality. 相似文献
12.
13.
14.
An examination of depression through the lens of spinal cord injury: Comparative prevalence rates and severity in women and men 总被引:1,自引:0,他引:1
PURPOSE: This study describes the prevalence of probable major depressive disorder (MDD) as well as other depressive disorders (ODD) and severity of depressive symptoms in a national sample of women with spinal cord injury (SCI) and compares them with a case-matched sample of men with SCI. METHODS: A sample of 585 women was drawn and case-matched with men from the SCI Model System National SCI Database according to level/completeness of injury, follow-up year, and age. The outcome measure of depression was the Patient Health Questionnaire. MAIN FINDINGS: Prevalence rates for women were 7.9% for probable MDD and 9.7% for ODD; rates for men were 9.9% and 10.3%, respectively. Logistic regression revealed that women who were divorced or at year 1 follow-up had a higher odds of having probable MDD (odds ratio [OR], 3.4 and 2.9, respectively). Employed women and men had significantly lower odds of probable MDD (OR, 0.274 and 0.358, respectively). Statistically significant differences were not found in gender comparisons for either probable MDD or symptom severity, which also were not associated with injury characteristics. CONCLUSION: The most significant, and unexpected, research finding is the absence of gender differences in probable MDD and symptom severity. Results challenge notions that depression will necessarily follow SCI; that injury characteristics determine the development and severity of depression; and that women experience a greater burden of depression than men. The main clinical implication is that depression screening and referral should be a routine feature of health care for women living with SCI, as well as for their male counterparts. Furthermore, nearly one fourth of women and men reported experiencing some or greater difficulty in daily life and relationships in the absence of probable depressive disorder, warranting monitoring of subsyndromal depression as well. 相似文献
15.
RPE Reynolds 《Journal canadien de gastroenterologie》2007,21(11):697-698
16.
Aisling Mary McMahon Fardod O'Kelly Kheng Tian Lim Narayanasamy Ravi John Vincent Reynolds 《Patient safety in surgery》2009,3(1):19
Esophageal perforation is associated with a significant risk of morbidity and mortality. We report herein a case of lye-induced
esophageal perforation managed successfully by employing endoscopic T-tube placement with a successful outcome. 相似文献
17.
Association of Hypoalbuminemia on the First Postoperative Day and Complications Following Esophagectomy 总被引:1,自引:0,他引:1
Aoife M. Ryan Aine Hearty Ruth S. Prichard Aileen Cunningham Suzanne P. Rowley John V. Reynolds 《Journal of gastrointestinal surgery》2007,11(10):1355-1360
Objective Changes in serum albumin may reflect systemic immunoinflammation and hypermetabolism in response to insults such as trauma
and sepsis. Esophagectomy is associated with a major metabolic stress, and the aim of this study was to determine if the absolute
albumin level on the first postoperative day was of value in predicting in-hospital complications.
Methods A retrospective study of 200 patients undergoing esophagectomy for malignant disease at St. James Hospital between 1999 and
2005 was performed. Patients who had pre and postoperative (days 1, 3, and 7) serum albumin levels measured were included
in the study. Patients were subdivided into three postoperative albumin categories <20 g/l, 20–25 g/l, >25 g/l. Logistic regression
analysis was performed to calculate the odds of morbidity and mortality according to the day 1 albumin level.
Results Patients with an albumin of less than 20 g/l on the first postoperative day were twice as likely to develop postoperative
complications than those with an albumin of greater than 20 g/l (54 vs 28% respectively, p < 0.011). Correspondingly, these patients also had a significantly higher rate of Adult Respiratory Distress Syndrome (22
vs 5%, p < 0.001), respiratory failure (27 vs 8%, p < 0.01) and in-hospital mortality (27 vs 6% (p < 0.001). On multivariate logistic regression analysis, day 1 albumin level was independently related to postoperative complications
(odds ratios, 0.89: 95%; confidence intervals, 0.83–0.96; p < 0.005). In addition, albumin <20 g/l on the first postoperative day was associated with the need for further surgery and
a return to ICU.
Conclusion Serum albumin concentration on the first postoperative day is a better predictor of surgical outcome than many other preoperative
risk factors. It is a low cost test that may be used as a prognostic tool to detect the risk of adverse surgical outcomes. 相似文献
18.
Hillary R Bogner Mark S Cary Martha L Bruce Charles F Reynolds Benoit Mulsant Thomas Ten Have George S Alexopoulos 《The American journal of geriatric psychiatry》2005,13(10):861-868
OBJECTIVE: The authors described the influence of specific medical conditions on clinical remission and response of major depression (MDD) in a clinical trial evaluating a care-management intervention among older primary-care patients. METHODS: Adults age 60 years and older were randomly selected and screened for depression. Participants were randomly assigned to Usual Care or to an Intervention with a depression care-manager offering algorithm-based care for MDD. In all, 324 adults meeting criteria for MDD were included in these analyses. Remission and response was defined by a score on the Hamilton Rating Scale for Depression <10 and by a decrease from baseline of > or =50%, respectively. Medical comorbidity was ascertained through self-report. Cognitive impairment was defined by a score <24 on the Mini-Mental State Exam (MMSE). RESULTS: In Usual Care, rates of remission were faster in persons who reported atrial fibrillation (AF) than in persons who did not report AF and slower in persons who reported chronic pulmonary disease than in persons who did not report chronic pulmonary disease; rates of response were less stable in persons with MMSE <24 than in those with MMSE > or =24. In the Intervention condition, none of the specific chronic medical conditions were significantly associated with outcomes for MDD. CONCLUSIONS: Because disease-specific findings were observed in persons who received Usual Care but not in persons who received more intensive treatment in the Intervention condition, our results suggest that the association of medical comorbidity and treatment outcomes for MDD may be determined by the intensity of treatment for depression. 相似文献
19.
G. N. Smith Jr E. A. Mickler K. K. Payne J. Lee M. Duncan J. Reynolds B. Foresman D. S. Wilkes 《American journal of transplantation》2007,7(7):1856-1861
Parenchymal disease in the allograft lung is associated with interstitial remodeling believed to be mediated by matrix metalloproteinases (MMPs). Recent studies suggest high levels of MMP-9 are associated with bronchiolitis obliterans syndrome (BOS) in lung transplant recipients. Since BOS occurs late in the posttransplant period and may be preceded by episodes of acute rejection or infection, which are associated with interstitial remodeling, we examined MMP profiles in allograft bronchoalveolar lavage (BAL) fluid in the early posttransplant period (preceding BOS). Gelatin zymography, protein array analysis and specific ELISA on BAL fluids from transplanted lungs indicated that MMP-8, MMP-9 and TIMP-1 were strongly expressed in allograft BAL fluid from stable patients, or those with infection or rejection compared to BAL fluid from normal volunteers. Elevated expression of MMP-8, MMP-9 and TIMP-1 occurred early, and was sustained for the 3.2 years covered in this study. Elevations of MMP-8, MMP-9 and TIMP-1 in the first 2 years posttransplant appear to be associated with lung transplantation itself, and not infection or rejection. These data suggest that ongoing and clinically silent MMP activity could perpetuate progressive disease in the allograft lung. 相似文献
20.
Much of the connective tissue degradation that takes place in periodontal diseases is mediated by proteolytic enzymes. Previous studies have focused on the action of proteinases released by invading polymorphonuclear neutrophils and macrophages, and bacterial enzymes. In view of recent work establishing that resident connective tissue cells can be induced by cytokines to bring about the destruction of their own matrix, we propose a new hypothesis. In this we envisage that a critical step is the interaction of bacterial antigens with inflammatory cells, resulting in the production of a cytokine, interleukin-1. Our interpretation of in vitro evidence is that the loss of connective tissue attachment and bone matrix resorption in periodontal diseases is mediated by metalloproteinases such as collagenase and stromelysin released by cells of the periodontium. Such proteolytic destruction can be induced by interleukin-1, whose production may not be dependent on a specific microbial flora but may be triggered by a number of organisms. It is now clear that interleukin-1 has multiple actions on both immune and non-immune cells; these include the induction of lymphocyte differentiation and proliferation and the stimulation of bone and cartilage resorption, and prostaglandin and metalloproteinase synthesis by connective tissues. It seems likely that further knowledge about the production and function of this cytokine will have an increasing impact in many diseases that involve resorption, particularly since interleukin-1-like molecules can be produced by cell types other than monocytes/macrophages, including keratinocytes and fibroblasts. 相似文献