全文获取类型
收费全文 | 4677篇 |
免费 | 482篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 34篇 |
儿科学 | 173篇 |
妇产科学 | 61篇 |
基础医学 | 715篇 |
口腔科学 | 125篇 |
临床医学 | 562篇 |
内科学 | 861篇 |
皮肤病学 | 92篇 |
神经病学 | 590篇 |
特种医学 | 149篇 |
外科学 | 517篇 |
综合类 | 63篇 |
一般理论 | 2篇 |
预防医学 | 516篇 |
眼科学 | 38篇 |
药学 | 254篇 |
中国医学 | 1篇 |
肿瘤学 | 409篇 |
出版年
2023年 | 49篇 |
2022年 | 73篇 |
2021年 | 126篇 |
2020年 | 80篇 |
2019年 | 139篇 |
2018年 | 127篇 |
2017年 | 106篇 |
2016年 | 105篇 |
2015年 | 121篇 |
2014年 | 142篇 |
2013年 | 219篇 |
2012年 | 299篇 |
2011年 | 285篇 |
2010年 | 144篇 |
2009年 | 124篇 |
2008年 | 219篇 |
2007年 | 197篇 |
2006年 | 185篇 |
2005年 | 171篇 |
2004年 | 167篇 |
2003年 | 163篇 |
2002年 | 149篇 |
2001年 | 99篇 |
2000年 | 100篇 |
1999年 | 120篇 |
1998年 | 37篇 |
1997年 | 44篇 |
1996年 | 44篇 |
1995年 | 38篇 |
1994年 | 37篇 |
1992年 | 78篇 |
1991年 | 79篇 |
1990年 | 60篇 |
1989年 | 64篇 |
1988年 | 53篇 |
1987年 | 61篇 |
1986年 | 53篇 |
1985年 | 39篇 |
1984年 | 53篇 |
1983年 | 40篇 |
1982年 | 42篇 |
1981年 | 37篇 |
1980年 | 29篇 |
1979年 | 39篇 |
1978年 | 41篇 |
1977年 | 35篇 |
1976年 | 32篇 |
1975年 | 35篇 |
1974年 | 34篇 |
1973年 | 40篇 |
排序方式: 共有5162条查询结果,搜索用时 9 毫秒
991.
992.
Ahmed S Horton KM Jeffrey RB Sheth S Fishman EK 《AJR. American journal of roentgenology》2010,195(5):1066-1071
OBJECTIVE: This article will review the current literature regarding the detection of thyroid nodules with an emphasis on CT diagnosis. We will also discuss management strategies. CONCLUSION: With advances in cross-sectional imaging, the detection of incidental thyroid nodules has increased significantly. Detection of thyroid nodules is common on chest CT that is being performed for unrelated reasons. The workup of these nodules can be timeconsuming and expensive. 相似文献
993.
994.
Aspartate-594 is the third most common BRAF residue mutated in human cancer. Mutants of this residue are kinase inactive, and the mechanism(s) by which they contribute to cancer has remained perplexing. Using a conditional knock-in mouse model, we show that the (D594A)Braf mutant does not drive tumor development per se but is able to induce aneuploidy in murine splenocytes and mouse embryonic fibroblasts and contributes to immortalization through the propagation of aneuploid cells. (D594A)Braf lacks kinase activity but induces the related gene product Craf as well as the mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK pathway. Here, we show that the aneuploid phenotype is dependent on Craf. Treatment with the MEK inhibitor U0126 did not attenuate the emergence of aneuploidy but prevented the growth of aneuploid cells. These results provide a previously unidentified link between Craf and chromosomal stability, with important implications for our understanding of the development of cancers with driver mutations that hyperactivate Craf. 相似文献
995.
Michael P. Mays MD Robert C. G. Martin MD PhD Alison Burton BA Brooke Ginter BA Michael J. Edwards MD Douglas S. Reintgen MD Merrick I. Ross MD Marshall M. Urist MD Arnold J. Stromberg PhD Kelly M. McMasters MD PhD Charles R. Scoggins MD MBA 《Cancer》2010,116(6):1535-1544
BACKGROUND:
Sentinel lymph node (SLN) biopsy generally is recommended for patients who have melanoma with a Breslow thickness ≥1 mm. Most patients with melanoma between 1 mm and 2 mm thick have tumor‐negative SLNs and an excellent long‐term prognosis. The objective of the current study was to evaluate prognostic factors in this subset of patients and determine whether all such patients require SLN biopsy.METHODS:
Patients with melanoma between 1 mm and 2 mm in Breslow thickness were evaluated from a prospective multi‐institutional study of SLN biopsy for melanoma. Disease‐free survival (DFS) and overall survival (OS) were evaluated by Kaplan‐Meier analysis to compare patients with melanoma that measured from 1.0 mm to 1.59 mm (Group A) versus patients with melanoma that measured from ≥1.6 mm to 2.0 mm thick (Group B). Univariate and multivariate analyses were performed to evaluate factors predictive of tumor‐positive SLN status, DFS, and OS.RESULTS:
The current analysis included 1110 patients with a median follow‐up of 69 months. SLN status was tumor‐positive in 133 of 1110 patients (12%) including 66 of 762 patients (8.7%) in Group A and 67 of 348 patients (19.3%) in Group B (P < .0001). On multivariate analysis, age, Breslow thickness, and lymphovascular invasion were independently predictive of a tumor‐positive SLN (P < .05). DFS (P < .0001) and OS (P = .0001) were significantly better for Group A than for Group B. When tumor thickness was treated as either a continuous variable (P < 0.0001) or a categorical variable (P < .0001), it was significantly predictive of DFS and OS. On multivariate analysis, Breslow thickness, age, ulceration, histologic subtype, regression, Clark level, and SLN status were significant factors predicting DFS; and Breslow thickness, age, primary tumor location, sex, ulceration, and SLN status were significant factors predicting OS (P < .05). A subgroup of patients who had tumors <1.6 mm in Breslow thickness, had no lymphovascular invasion, and were aged ≥59 years had a low risk (5%) of tumor‐positive SLN.CONCLUSIONS:
The current findings indicated that there is significant diversity in the biologic behavior of melanoma between 1 mm and 2 mm in Breslow thickness. SLN biopsy is recommended for all such patients to identify those with lymph node metastasis who are at the greatest risk of recurrence and mortality. Cancer 2010. © 2010 American Cancer Society. 相似文献996.
997.
Werle J Dobbelsteyn L Feasel AL Hancock B Job B Makar L Manning H Quigley S Teppler A Smith C Kelly S Wasylak T 《Forum gestion des soins de santé》2010,23(4):169-174
This study evaluates the effectiveness of a performance-focused methodology for engaging multidisciplinary, frontline healthcare teams in making behavioural changes that improve patient care and health system efficiency. Results include significant declines in average length of stay in hospital and waiting time for surgery, and a dramatic increase in early patient ambulation. Performance-focused methodology using key performance indicators, targets, measurement, and ongoing feedback, supported by non-monetary incentives, can quickly improve healthcare outcomes. 相似文献
998.
James R. Conner Emily Meserve Ellen Pizer Judy Garber Michael Roh Nicole Urban Charles Drescher Bradley J. Quade Michael Muto Brooke E. Howitt Mark D. Pearlman Ross S. Berkowitz Neil Horowitz Christopher P. Crum Colleen Feltmate 《Gynecologic oncology》2014
Objective
This study computed the risk of clinically silent adnexal neoplasia in women with germ-line BRCA1 or BRCA2 mutations (BRCAm +) and determined recurrence risk.Methods
We analyzed risk reduction salpingo-oophorectomies (RRSOs) from 349 BRCAm + women processed by the SEE-FIM protocol and addressed recurrence rates for 29 neoplasms from three institutions.Results
Nineteen neoplasms (5.4%) were identified at one institution, 9.2% of BRCA1 and 3.4% of BRCA2 mutation-positive women. Fourteen had a high-grade tubal intraepithelial neoplasm (HGTIN, 74%). Mean age (54.4) was higher than the BRCAm + cohort without neoplasia (47.8) and frequency increased with age (p < 0.001). Twenty-nine BRCAm + patients with neoplasia from three institutions were followed for a median of 5 years (1–8 years.). One of 11 with HGTIN alone (9%) recurred at 4 years, in contrast to 3 of 18 with invasion or involvement of other sites (16.7%). All but two are currently alive. Among the 29 patients in the three institution cohort, mean ages for HGTIN and advanced disease were 49.2 and 57.7 (p = 0.027).Conclusions
Adnexal neoplasia is present in 5–6% of RRSOs, is more common in women with BRCA1 mutations, and recurs in 9% of women with HGTIN alone. The lag in time from diagnosis of the HGTIN to pelvic recurrence (4 years) and differences in mean age between HGTIN and advanced disease (8.5 years) suggest an interval of several years from the onset of HGTIN until pelvic cancer develops. However, some neoplasms occur in the absence of HGTIN. 相似文献999.
Allison L. Cohen Julia B. Wenger Tamarra James-Todd Brooke M. Lamparello Elizabeth Halprin Shanti Serdy 《Hypertension in pregnancy》2014,33(1):81-92
Objective: To assess whether glycemic control, soluble fms-like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF) were associated with the development of preeclampsia (PE) or gestational hypertension (GHTN) in women with preexisting diabetes. Methods: Maternal circulating angiogenic factors (sFlt1 and PlGF) measured on automated platform were studied at four time points during pregnancy in women with diabetes (N?=?159) and reported as multiples of the median (MOM) of sFlt1/PlGF ratio (median, 25th–75th percentile) noted in non-diabetic non-hypertensive control pregnant population (N?=?139). Diagnosis of PE or GHTN was determined by review of de-identified clinical data. Results: PE developed in 12% (N?=?19) and GHTN developed in 23% (N?=?37) of the women with diabetes. Among diabetic women without PE or GHTN, median sFlt1/PlGF levels at 35–40 weeks was threefold higher than in non-diabetic controls [MOM 3.21(1.19–7.24), p?=?0.0001]. Diabetic women who subsequently developed PE had even greater alterations in sFlt1/PlGF ratio during the third trimester [MOM for PE at 27–34 weeks 15.18 (2.37–26.86), at 35–40 weeks 8.61(1.20–18.27), p?≤?0.01 for both windows compared to non-diabetic controls]. Women with diabetes who subsequently developed GHTN also had significant alterations in angiogenic factors during third trimester; however, these findings were less striking. Among women with diabetes, glycosylated hemoglobin (HbA1c) during the first trimester was higher in subjects who subsequently developed PE (7.7 vs 6.7%, p?=?0.0001 for diabetic PE vs diabetic non-PE). Conclusions: Women with diabetes had a markedly altered anti-angiogenic state late in pregnancy that was further exacerbated in subjects who developed PE. Altered angiogenic factors may be one mechanism for the increased risk of PE in this population. Increased HbA1c in the first trimester of pregnancies in women with diabetes was strongly associated with subsequent PE. 相似文献
1000.
Oncogenic types of the human papillomavirus (HPV) are firmly established as etiological agents for most premalignant and malignant epithelial lesions of the cervical mucosa. Genital infection with HPV is the most common sexually transmitted infection (STI) in the United States. Although most women infected with the virus become HPV negative within 2 years, women with persistent high-risk HPV infections are at greatest risk for developing cervical cancer. Since the development of the Papanicolau (Pap) test more than 60 years ago to screen for cervical cancer, technological advances have occurred in cervical cytology screening and HPV vaccine research. For example, in 2001, high-risk HPV DNA testing was recommended for the management of women whose Pap smears (collected by a liquid-based method) reveal atypical squamous cells of undetermined significance. In 2006, the Food and Drug Administration licensed a quadrivalent HPV vaccine for females aged 9-26 years to prevent cervical cancer, precancerous lesions, and genital warts associated with HPV types in the vaccine. New and emerging technologies in cancer diagnosis, management, and prevention are often addressed in comprehensive cancer control (CCC) plans developed by states, tribes, and territories. CCC is a collaborative process through which a community and its partners pool resources to reduce the burden of cancer. To assess whether CCC plans include HPV-related content, particularly regarding cervical cancer screening and prevention, we reviewed the most current plans available between October 2006 and January 2007 on an interactive Internet site for CCC programs (n = 53). This paper describes the contexts in which HPV-related content occurs in the plans. 相似文献