全文获取类型
收费全文 | 16986篇 |
免费 | 1690篇 |
国内免费 | 634篇 |
专业分类
耳鼻咽喉 | 258篇 |
儿科学 | 176篇 |
妇产科学 | 345篇 |
基础医学 | 1448篇 |
口腔科学 | 466篇 |
临床医学 | 1529篇 |
内科学 | 1850篇 |
皮肤病学 | 102篇 |
神经病学 | 713篇 |
特种医学 | 690篇 |
外国民族医学 | 8篇 |
外科学 | 3197篇 |
综合类 | 2849篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 928篇 |
眼科学 | 137篇 |
药学 | 2197篇 |
26篇 | |
中国医学 | 989篇 |
肿瘤学 | 1397篇 |
出版年
2024年 | 33篇 |
2023年 | 248篇 |
2022年 | 436篇 |
2021年 | 621篇 |
2020年 | 563篇 |
2019年 | 538篇 |
2018年 | 636篇 |
2017年 | 591篇 |
2016年 | 631篇 |
2015年 | 582篇 |
2014年 | 1018篇 |
2013年 | 1229篇 |
2012年 | 923篇 |
2011年 | 977篇 |
2010年 | 778篇 |
2009年 | 749篇 |
2008年 | 818篇 |
2007年 | 715篇 |
2006年 | 721篇 |
2005年 | 651篇 |
2004年 | 649篇 |
2003年 | 614篇 |
2002年 | 579篇 |
2001年 | 448篇 |
2000年 | 426篇 |
1999年 | 367篇 |
1998年 | 366篇 |
1997年 | 301篇 |
1996年 | 292篇 |
1995年 | 274篇 |
1994年 | 233篇 |
1993年 | 199篇 |
1992年 | 166篇 |
1991年 | 162篇 |
1990年 | 114篇 |
1989年 | 98篇 |
1988年 | 69篇 |
1987年 | 63篇 |
1986年 | 41篇 |
1985年 | 54篇 |
1984年 | 54篇 |
1983年 | 39篇 |
1982年 | 34篇 |
1981年 | 23篇 |
1980年 | 23篇 |
1979年 | 19篇 |
1978年 | 25篇 |
1977年 | 23篇 |
1976年 | 18篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
The effects of combined use of earthworm extract(912)and HpD-laser on the produc-tion of reactive oxygen and the biosynthesis of DNA in S_(180) tumor cells were studied throughchemiluminescence measurement and[~3H]-TdR incorporation assay.The results showed that as com-pared with the control,the intensity of chemiluminescence emitted by tumor cells treatedsimultaneously with 912 and HpD-laser was enhanced more than ten-folds,while that treated with912 or HpD-laser alone was increased only 2~4 folds.The[~3H]-TdR incorporation into tumorcells of the former group was inhibited upto 74.1%,and that of the latter groups decreased onlyby 42.2% and 40.0%,respectively.In accordance with these biochemical changes,the ultrastructuraldamage of tumor cells of the former,combinedly treated group appeared to be the most serious.This suggests an additive effect of 912 with HpD-laser on tumor cells.In addition,if free radicalscavengers,such as catalase and superoxide dismutase,were added to the reaction systembefore chemiluminescence assay,the luminescent enhancement effect mentioned above was dramaticallyalleviated,implying the presence of O_2~ and H_2O_2 in the system.Therefore,as to the toxic effecton tumor cells,912 and HpD-laser are not only additive in efficiency,but also similar in theunderlying mechanism of action. 相似文献
73.
Shun'Ichi Abe Hiroshi Yoshimura Hideki Tabara Mitsuo Tachibana Naomi Monden Teruhisa Nakamura Saburou Nagaoka 《Journal of surgical oncology》1995,59(4):226-229
Patients with stage T3N0~2M0 gastric carcinoma (n = 108) were studied for relevant prognostic factors. Peritoneal lavage cytology (PLC) was performed in all. In univariate analysis, 5-year survival rates were better with smaller serosal invasion (diameter <3.0 cm vs. ≥3.0 cm, 61% vs. 37%, P < 0.05) and fewer metastatic nodes (≤5 vs. ≥6, 57% vs. 29%, P < 0.05). In multivariate analyses, only these two factors were significant. The predictive value of PLC was not shown in both univariate and multivariate analyses. Peritoneal recurrence occured in 14 (22%) of 77 patients with negative PLC, and in 3 (18%) of 17 with positive PLC, the difference being not significant. Our results indicate that PLC is insensitive in predicting the development of peritoneal recurrence. Its role in the estimation of survival is limited, as many will die of visceral or locoregional recurrence if not of peritoneal dissemination. 相似文献
74.
75.
A M Abdel Gader A A Al-Mishari S A Awadalla N M Buyuomi T Khashoggi M Al-Hakeem 《International journal of gynaecology and obstetrics》2006,95(3):248-253
OBJECTIVE: To clarify the role played by tissue factor pathway inhibitor (TFPI) in pregnancy hypertension. METHODS: Using enzyme-linked immunosorbent assays, hemostatic measurements were obtained for women with pre-eclampsia (n=51), nonproteinuric hypertension of pregnancy (n=62), postpartum pre-eclampsia 24 h after childbirth (n=31), and no hypertension (healthy pregnant controls, n=100). RESULTS: There was a significant increase in circulating free TFPI levels in women with pre-eclampsia (9.7+/-6.2 ng/mL) or nonproteinuric hypertension of pregnancy (8.3+/-5.3 ng/mL) compared with healthy controls (5.3+/-2.1 ng/mL). In women with pre-eclampsia the levels remained elevated after placental delivery (10.6+/-4.0 ng/mL). Free protein S levels were significantly higher in women with pre-eclampsia (40.0%+/-10.7%), nonproteinuric hypertension of pregnancy (37.1%+/-12.5%), or postpartum pre-eclampsia (39.3%+/-9.1%) than in healthy pregnant controls (32.2%+/-8.5%). CONCLUSION: Increased levels of the physiologically active free forms of TFPI and free protein S, 2 coagulation inhibitors, may protect women with pregnancy-induced hypertension from the risks of hemostatic activation. 相似文献
76.
影响原发性肝癌根治术后近期和远期复发的临床病理因素 总被引:2,自引:0,他引:2
目的 :探讨根治性肝癌术后近期和远期复发因素 ,以期对高复发倾向人群抗复发提出针对性对策。方法 :回顾分析 1994年 5月~ 1998年 1月 16 2例根治性肝癌切除病例的临床资料 ,以影像学发现肿瘤复发及患者死亡或末次随访日期为截点确定无瘤生存时间 ,将术后复发病人分为近期复发 (≤ 2年 )、远期复发 (>2年 )及未复发 3组 ,确定复发危险因素。结果 :本组术后 1、 3、 5年无瘤生存率分别为 6 7. 1、 4 4 . 7及 2 5 . 5 %。与肿瘤近期复发相关因素为发现方式、肿瘤大小、血管癌栓、INM分期 ;与后期复发相关因素为有无肝硬化及其类型、肝功Child -Pugh分级和有无子瘤。结论 :根治性肝癌切除术后近期和远期复发的临床病理因素不同 ,及早发现小肝癌是预防近期复发的关键 ,兼顾术前肝功能可以对远期复发有预测作用 相似文献
77.
Multicoil Dixon chemical species separation with an iterative least-squares estimation method. 总被引:1,自引:0,他引:1
Scott B Reeder Zhifei Wen Huanzhou Yu Angel R Pineda Garry E Gold Michael Markl Norbert J Pelc 《Magnetic resonance in medicine》2004,51(1):35-45
This work describes a new approach to multipoint Dixon fat-water separation that is amenable to pulse sequences that require short echo time (TE) increments, such as steady-state free precession (SSFP) and fast spin-echo (FSE) imaging. Using an iterative linear least-squares method that decomposes water and fat images from source images acquired at short TE increments, images with a high signal-to-noise ratio (SNR) and uniform separation of water and fat are obtained. This algorithm extends to multicoil reconstruction with minimal additional complexity. Examples of single- and multicoil fat-water decompositions are shown from source images acquired at both 1.5T and 3.0T. Examples in the knee, ankle, pelvis, abdomen, and heart are shown, using FSE, SSFP, and spoiled gradient-echo (SPGR) pulse sequences. The algorithm was applied to systems with multiple chemical species, and an example of water-fat-silicone separation is shown. An analysis of the noise performance of this method is described, and methods to improve noise performance through multicoil acquisition and field map smoothing are discussed. 相似文献
78.
G. Kostopanagiotou A. Pandazi I. Andreadou A. Doufas I. Chondroudaki T. Kotsis D. Rizos C. Costopanagiotou V. Smyrniotis 《European journal of vascular and endovascular surgery》2005,30(6):648-653
OBJECTIVE: We investigated the dose-related effect of dopexamine and dopamine on free radical production and lipid peroxidation estimated by MDA measurements in an ischaemia-reperfusion model of supraceliac aortic repair. DESIGN: Prospective, randomized, blinded experimental study. MATERIALS: Twenty-five healthy pigs. METHODS: All experiments were performed under general endotracheal anaesthesia. Supraceliac aortic cross clamping was performed in all pigs. The pigs were randomly assigned into five groups (n=5 in each group) and received a continuous intravenous infusion of normal saline (CTL), dopamine 2 microg kg(-1)min(-1) (dopa 2), dopamine 8 microg kg(-1)min(-1) (dopa 8), dopexamine 2 microg kg(-1)min(-1) (dopex 2), dopexamine 8 microg kg(-1)min(-1) (dopex 8). Cardiac output, mean arterial pressure, arterial blood gas analysis and blood sampling for plasma MDA measurements (to reveal lipid peroxidation) were recorded after induction of anaesthesia (baseline), 60 and 120 min after cross-clamping of aorta (ischaemia phase), and 60 and 120 min after restoration of flow (reperfusion phase). RESULTS: Dopexamine and dopamine at 8 microgkg(-1)min(-1) reduced MDA at 60 and 120 min after reperfusion. CONCLUSION: Dopexamine seems superior to dopamine in reducing oxygen free radicals and subsequent lipid peroxidation during reperfusion after supraceliac aortic cross clamping in pigs. 相似文献
79.
Dr. Joseph A. Kuhn MD Lawrence D. Wagman MD John A. Lorant MD Fredrick W. Grannis MD Mordecai Dunst MD William R. Dougherty MD Daniel I. Jacobs MD 《Annals of surgical oncology》1994,1(4):353-359
Background: A radical forequarter amputation with partial chest wall resection (one to four ribs) has been reported for benign and malignant
lesions involving the shoulder and chest wall region. Concerns about reconstruction and postoperative pulmonary function have
previously limited more extensive chest wall resections. The current report describes the first case in which a complete unilateral
anterior and posterior chest wall resection and pneumonectomy (hemithoracectomy) accompany a forequarter amputation. A novel
reconstructive technique used the full circumference of the forearm tissue with an intact ulna as a free osseomyocutaneous
flap.
Methods: In this case, a 21-year-old patient presented with an extensive recurrent desmoid tumor that involved the shoulder, brachial
plexus, subclavian vein, and chest wall from the lateral sternal border to the midportion of the scapula and down to the eighth
rib. The operative technique involved removal of the entire right hemithorax from the midline sternum to the transverse process
posteriorly, down to the ninth rib inferiorly. Due to the absence of a rigid hemithorax, the uninvolved ipsilateral lung was
also removed. The forearm flap was prepared before final separation of the specimen and division of the subclavian vessels.
Results: Postoperatively, the patient maintained excellent oxygenation without atelectasis or fever and was extubated on the 15th
postoperative day. As expected after pneumonectomy, significant decreases from preoperative to immediate postoperative values
were noted for the vital capacity (VC) (from 4.87 L to 1.29 L), forced 1-s expiratory volume (FEV1) (from 3.77 L to 1.02 L),
and inspiratory capacity (IC) (3.33 1 to 0.99 1). Rehabilitation included a specially designed external prosthesis to provide
cosmesis and prevent scoliosis. By the 15th postoperative week the patient had returned to normal social and physical activities,
with a gradual improvement in all respiratory parameters: VC 1.52 L, FEV1 1.29 L, IC 1.04 L. There has been no evidence of
tumor recurrence at 1 year.
Conclusions: This report provides evidence that a complete hemithoracectomy, pneumonectomy, and forequarter amputation can be safely performed
for selective tumors involving the shoulder region with extensive chest wall invasion. Reconstruction may be achieved with
an extended forearm osseomyocutaneous free flap with an excellent functional outcome.
Presented at the 46th Annual Cancer Symposium of The Society of Surgical Oncology, Los Angeles, California, March 18–21, 1993. 相似文献
80.
A. Barutçu 《European journal of plastic surgery》1994,17(6):316-318
Summary Pedicled temporoparietal fascial flaps have been used extensively in head and neck reconstruction for many years. Also, the fascia has been grafted, and the skin graft transformed into a vascularized pedicled flap (prefabricated temporoparietal fasciocutaneous flap). On the other hand, some authors have used free temporoparietal fascial flaps for defects that require to be filled in lower and upper extremity wounds. In this case, a free prefabricated temporoparietal fascio-chondro-cutaneous flap having only an arterial inflow was used in eyelid reconstruction.Presented at the 14th Congress of Turkish Plastic and Reconstructive Surgery, Ankara, Turkey, October 1992 相似文献