全文获取类型
收费全文 | 49743篇 |
免费 | 3111篇 |
国内免费 | 155篇 |
专业分类
耳鼻咽喉 | 653篇 |
儿科学 | 1422篇 |
妇产科学 | 856篇 |
基础医学 | 5897篇 |
口腔科学 | 804篇 |
临床医学 | 5053篇 |
内科学 | 10696篇 |
皮肤病学 | 860篇 |
神经病学 | 4634篇 |
特种医学 | 1997篇 |
外国民族医学 | 1篇 |
外科学 | 8710篇 |
综合类 | 474篇 |
一般理论 | 48篇 |
预防医学 | 3126篇 |
眼科学 | 807篇 |
药学 | 3044篇 |
中国医学 | 45篇 |
肿瘤学 | 3882篇 |
出版年
2023年 | 246篇 |
2022年 | 416篇 |
2021年 | 1082篇 |
2020年 | 625篇 |
2019年 | 1099篇 |
2018年 | 1304篇 |
2017年 | 952篇 |
2016年 | 990篇 |
2015年 | 1171篇 |
2014年 | 1820篇 |
2013年 | 2320篇 |
2012年 | 3742篇 |
2011年 | 3895篇 |
2010年 | 2179篇 |
2009年 | 1863篇 |
2008年 | 3406篇 |
2007年 | 3582篇 |
2006年 | 3562篇 |
2005年 | 3465篇 |
2004年 | 3333篇 |
2003年 | 3100篇 |
2002年 | 2848篇 |
2001年 | 378篇 |
2000年 | 263篇 |
1999年 | 398篇 |
1998年 | 567篇 |
1997年 | 457篇 |
1996年 | 349篇 |
1995年 | 347篇 |
1994年 | 327篇 |
1993年 | 268篇 |
1992年 | 209篇 |
1991年 | 197篇 |
1990年 | 174篇 |
1989年 | 160篇 |
1988年 | 161篇 |
1987年 | 144篇 |
1986年 | 138篇 |
1985年 | 142篇 |
1984年 | 181篇 |
1983年 | 180篇 |
1982年 | 202篇 |
1981年 | 176篇 |
1980年 | 124篇 |
1979年 | 83篇 |
1978年 | 77篇 |
1977年 | 69篇 |
1976年 | 43篇 |
1975年 | 30篇 |
1974年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
A primary intrascrotal mass clinically mimicking a testicular tumor was found to be a desmoid tumor originating from the spermatic cord. To our knowledge, this is the first reported case of a paratesticular desmoid tumor. 相似文献
12.
Physiologic mechanism and preoperative prediction of new-onset dysphagia after laparoscopic Nissen fundoplication 总被引:2,自引:0,他引:2
Dennis Blom M.D. Jeffrey H. Peters M.D. Tom R. DeMeester M.D. Peter F. Crookes M.D. Jeffrey A. Hagan M.D. Steven R. DeMeester M.D. Cedric Bremner M.D. 《Journal of gastrointestinal surgery》2002,6(1):22-28
The aim of this study was to determine whether preoperative physiologic factors can account for and be used to predict the
development of postoperative dysphagia after laparoscopic Nissen fundoplication. One hundred sixty-three patients with gastroesophageal
reflux disease underwent laparoscopic Nissen fundoplication with a median follow-up of 14 months (range 6 to 81 months). Preoperative
dysphagia was present in 37% (60 of 163) and was relieved in all but five patients (92%). Female sex (P = 0.01) and the presence of a stricture (P = 0.02) were the only preoperative variables associated with the presence of preoperative dysphagia. Eight percent (8 of
103) of patients without preoperative dysphagia developed new-onset dysphagia, and of these 63% (5 of 8) had a normal lower
esophageal sphincter (LES) (pressure >6 mm Hg; length >2 cm; abdominal length >1 cm). New-onset dysphagia was significantly
more common in patients with a normal LES (22% [5 of 23] vs. 4% [3 of 80], P = 001). Patients with a normal LES had almost a sixfold increase in the risk of developing dysphagia as those with an abnormal
LES (relative risk = 5.8). Only a preoperative normal LES (P = 0.02) or mean LES pressures (P = 0.04) were positively associated with the development of postoperative dysphagia. The severity of this dysphagia also showed
a strong positive trend of increasing with mean preoperative LES pressures (P = 0.07). Finally, preoperative LES pressure significantly correlated with postoperative LES pressure (r = 0.48, P = 0.01) and with mean residual LES (nadir) pressure (r = 0.33, P = 0.05) offering insight into the mechanism of this dysphagia. In conclusion, preoperative LES parameters play a role in
the development of dysphagia after laparoscopic Nissen fundoplication. Patients with a normal LES or high mean LES pressures
are at increased risk for developing this complication and should be informed of this before laparoscopic Nissen fundoplication.
Presented at the Forty-Second Annual Meeting of The Society for Surgery of the Alimentary Tract, Atlanta, Ga., May 20–23,
2001. 相似文献
13.
14.
15.
Tooth movement and cytokines in gingival crevicular fluid and whole blood in growing and adult subjects. 总被引:1,自引:0,他引:1
Laura R Iwasaki Larry D Crouch Albert Tutor Scott Gibson Navin Hukmani David B Marx Jeffrey C Nickel 《American journal of orthodontics and dentofacial orthopedics》2005,128(4):483-491
INTRODUCTION: Tooth movement has been studied largely with respect to the force required for tipping when pressure distribution varies along the length of the periodontal ligament. But important factors for effective canine translation include the nature and magnitude of applied stress and the patient's cell biology. The purpose of this research was to test 3 hypotheses: (1) the velocity of tooth translation (v(t)) is related to applied stress and growth status, (2) a threshold of stress accounts for the lag phase, and (3) v(t) is correlated with the ratio (AI) of 2 cytokines (IL-1beta, IL-1RA) measured in gingival crevicular fluid (GCF) and stimulated whole blood (SWB). METHODS: Continuous maxillary canine retraction stresses of 13 kPa and 4, 26, or 52 kPa were applied bilaterally in 6 growing and 4 adult subjects for 84 days. Dental models and GCF samples were collected at 1- to 14-day intervals. Cytokines were measured in GCF and SWB cell cultures. RESULTS: V(t) was positively related to stress and was higher in growing subjects (P = .001). It was also related to AI(GCF) in growers (R2= 0.56) and nongrowers (R2= 0.72). Canines moved with 52 kPa showed a lag phase, and postlag phase AI(GCF) was twice that of lag phase AI(GCF). Mean v(t) and associated AI(GCF) during the postlag phase were nearly double the values for canines moved with 13 and 26 kPa. SWB production of cytokines was dose-dependent. For growing subjects, SWB IL-1RA was correlated with v(t) (R = 0.70-0.72), and AI(SWB) and IL-1beta concentrations were correlated with AI(GCF) (R = 0.73-0.78). CONCLUSIONS: V(t) varied with growth status and stresses < or = 52 kPa; stresses of < 52 kPa showed no lag phase; and equivalent stresses yielded subject-dependent differences in v(t), which correlated with cytokines in GCF and SWB. 相似文献
16.
We report 2 cases of diffuse intraperitoneal metastases from testicular carcinoma following transabdominal retroperitoneal lymphadenectomy. This is an unusual pattern of metastasis for nonseminomatous germ cell tumors and it is believed to be the result of direct seeding from lymphatic leakage secondary to surgery. The value of computerized tomography in diagnosing this entity is emphasized. 相似文献
17.
18.
19.
Preclinical and clinical investigations currently underway are employing novel strategies for combining vaccines with conventional and experimental anticancer therapies. To date, the FDA has not approved a therapeutic cancer vaccine. However, the results of recent investigations suggest an increasing role for vaccines in new models of combination therapy for many types of cancer. This article reviews and discusses therapeutic cancer strategies that employ vaccines in combination with local radiation, chemotherapy, hormone therapy, and anti-CTLA-4 mAb. Preclinical studies have shown that certain anticancer agents have immune modulatory effects that result in up-regulation of surface expression of MHC molecules, tumor-associated antigens, or Fas on malignant cells, rendering them more susceptible to immune destruction. Preliminary results of clinical studies using combination strategies have demonstrated a postvaccination antigen cascade, prolonged time to disease progression, and improved overall survival. Several larger randomized trials are ongoing, and more are required to support these findings. 相似文献
20.
Peter B. Richman MD Shari Dominguez MD David Kasper MD Frederick Chen MD Jeremy Friese MD Joseph Wood MD JD Joseph Collins MD Jeffrey A. Kline MD 《Academic emergency medicine》2006,13(3):295-301
Objectives: To determine interobserver agreement between radiologists for computed tomography (CT) angiography and venography. CT venography of the lower extremities combined with standard CT angiography of the chest may result in an increased overall diagnosis rate of venous thromboembolism (pulmonary embolism or deep venous thrombosis).
Methods: The study had a retrospective cohort design. The population consisted of emergency department patients who were evaluated for suspected pulmonary embolism. A random sample of 50 patients diagnosed and treated for venous thromboembolism and 50 age- and gender-matched patients whose CT angiograms and venograms were read as negative were enrolled. The original reading (R1) was compared with readings of two study radiologists: R2, a general radiologist, and R3, a radiologist with fellowship training in cross-sectional imaging. All readers were blinded to each other.
Results: Both R2 and R3 found both CT angiogram and venogram components technically adequate in 95% (95% CI = 89% to 98%) and 86% (95% CI = 78% to 92%) of studies, respectively. The agreement was very good for CT angiography (lowest agreement = 92%; lowest κ = 0.83) and was good for CT venography (85%, κ = 0.65). In nine cases, R1 read the CT angiogram as negative but the venogram as positive for DVT, whereas both R2 and R3 read both components as negative in four of these nine, suggesting a false-positive isolated DVT rate of 44% (95% CI = 19% to 73%). In no case did R1 read both scan components as negative when R2 and R3 agreed on presence of pulmonary embolism or DVT.
Conclusions: Diagnosis of pulmonary embolism on CT angiography is more reliable than diagnosis of isolated DVT on CT venography. 相似文献
Methods: The study had a retrospective cohort design. The population consisted of emergency department patients who were evaluated for suspected pulmonary embolism. A random sample of 50 patients diagnosed and treated for venous thromboembolism and 50 age- and gender-matched patients whose CT angiograms and venograms were read as negative were enrolled. The original reading (R1) was compared with readings of two study radiologists: R2, a general radiologist, and R3, a radiologist with fellowship training in cross-sectional imaging. All readers were blinded to each other.
Results: Both R2 and R3 found both CT angiogram and venogram components technically adequate in 95% (95% CI = 89% to 98%) and 86% (95% CI = 78% to 92%) of studies, respectively. The agreement was very good for CT angiography (lowest agreement = 92%; lowest κ = 0.83) and was good for CT venography (85%, κ = 0.65). In nine cases, R1 read the CT angiogram as negative but the venogram as positive for DVT, whereas both R2 and R3 read both components as negative in four of these nine, suggesting a false-positive isolated DVT rate of 44% (95% CI = 19% to 73%). In no case did R1 read both scan components as negative when R2 and R3 agreed on presence of pulmonary embolism or DVT.
Conclusions: Diagnosis of pulmonary embolism on CT angiography is more reliable than diagnosis of isolated DVT on CT venography. 相似文献