全文获取类型
收费全文 | 70941篇 |
免费 | 4851篇 |
国内免费 | 2031篇 |
专业分类
耳鼻咽喉 | 431篇 |
儿科学 | 956篇 |
妇产科学 | 596篇 |
基础医学 | 7637篇 |
口腔科学 | 1132篇 |
临床医学 | 6458篇 |
内科学 | 6856篇 |
皮肤病学 | 372篇 |
神经病学 | 8864篇 |
特种医学 | 2124篇 |
外国民族医学 | 2篇 |
外科学 | 4640篇 |
综合类 | 12964篇 |
现状与发展 | 7篇 |
一般理论 | 2篇 |
预防医学 | 11358篇 |
眼科学 | 710篇 |
药学 | 7789篇 |
179篇 | |
中国医学 | 2644篇 |
肿瘤学 | 2102篇 |
出版年
2024年 | 237篇 |
2023年 | 1074篇 |
2022年 | 2007篇 |
2021年 | 2736篇 |
2020年 | 2668篇 |
2019年 | 1940篇 |
2018年 | 1914篇 |
2017年 | 1977篇 |
2016年 | 2181篇 |
2015年 | 2182篇 |
2014年 | 4620篇 |
2013年 | 4880篇 |
2012年 | 4469篇 |
2011年 | 4927篇 |
2010年 | 3918篇 |
2009年 | 3736篇 |
2008年 | 3774篇 |
2007年 | 3592篇 |
2006年 | 3240篇 |
2005年 | 2720篇 |
2004年 | 2200篇 |
2003年 | 1936篇 |
2002年 | 1520篇 |
2001年 | 1319篇 |
2000年 | 1108篇 |
1999年 | 939篇 |
1998年 | 913篇 |
1997年 | 882篇 |
1996年 | 729篇 |
1995年 | 690篇 |
1994年 | 676篇 |
1993年 | 577篇 |
1992年 | 545篇 |
1991年 | 530篇 |
1990年 | 437篇 |
1989年 | 386篇 |
1988年 | 400篇 |
1987年 | 377篇 |
1986年 | 348篇 |
1985年 | 470篇 |
1984年 | 399篇 |
1983年 | 243篇 |
1982年 | 265篇 |
1981年 | 243篇 |
1980年 | 227篇 |
1979年 | 145篇 |
1978年 | 135篇 |
1977年 | 120篇 |
1976年 | 87篇 |
1974年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
L Mettler 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2002,6(4):305-309
BACKGROUND AND OBJECTIVES: Evaluation of long-term results using a thermal balloon endometrial ablation technique to treat menorrhagia and hypermenorrhea, considered dysfunctional uterine bleedings. METHODS: A single-arm, prospective study with long-term follow-up of 48 months at the department of obstetrics and gynecology, University of Kiel, Germany. Following hysteroscopic evaluation of the uterine cavity and fractionated curettage, the Cavaterm endometrial thermal ablation technique was performed on 70 patients over the age of 40 with menorrhagia and hypermenorrhea in whom medical treatment had previously failed. The study included a group of 10 patients with adenomyosis and uterine fibroids. RESULTS: In 65 patients, a complete 48-month follow-up evaluation was possible: 58% of patients reported amenorrhea and 33% hypomenorrhea. Nine percent of patients remained eumenorrheic. Fifty percent of the small group with failed indications for the procedure had to undergo a hysterectomy. CONCLUSIONS: The Cavaterm thermal coagulation system in the earlier mode of application (15 minutes at a temperature of 70 degrees C and a pressure of 200 mm Hg) is a safe and highly effective method of endometrial ablation resulting in a minimal amount of posttreatment menstrual bleeding. 相似文献
82.
目的 :研究老年人不同疾病时骨密度 (BMD)的分布情况。方法 :用DXADAS 6 0 0EX型骨密度仪对183例老年患者进行左侧远程桡骨加尺骨BMD检测。结果 :内分泌疾病组、消化道疾病组和其它疾病组的患病率分别为 72 7% ,2 0 6 %和 31 4 %。T值比较 :三组差异明显 (P <0 0 0 1)。累积骨丢失率 (ABLR)比较 :前一组明显高于后两组病人 (P <0 0 1)。BMD比较中 ,内分泌和其它疾病组明显低于消化道疾病组 (P <0 0 0 1)。相关分析显示 ,内分泌和消化道疾病组的年龄变化与BMD呈正相关 (r =0 5 19P <0 0 0 1和r =0 5 89P <0 0 0 1) ,内分泌疾病组和其它疾病组的体重变化与BMD呈正相关 (r=0 918P <0 0 0 1和r =0 338P <0 0 0 1)。结论 :老年人骨质疏松 (OP)患病率以内分泌疾病组最高 ,消化道疾病组较低 ;随年龄和体重增加 ,BMD降低加重。 相似文献
83.
Meng-Luen Lee Lon-Yen Tsao Wun-Tsong Chaou Albert D Yang Kun-Tu Yeh Jou-Kou Wang Mei-Hwan Wu Hung-Chi Lue Ing-Sh Chiu Chung-I Chang 《Pediatric pulmonology》2002,33(1):1-11
We propose a haphazard branching theory to support the concept of bronchopulmonary malinosculations, and we apply this theory to classify congenital bronchopulmonary vascular malformation (BPVM) based on the anatomical results we have found. Between January 1990 and December 1997, a total of 22 pediatric patients (10 male and 12 female), aged 2 days to 14 years (median, 19.6 months), with congenital BPVM were enrolled in this retrospective study. Study modalities include the clinical features and plain chest films (n = 22) plus at least two of the following: echocardiography (n = 13), barium esophagraphy (n = 2), bronchoscopy (n = 4), contrast bronchography (n = 8), high-resolution direct coronal CT (n = 1) and electron beam or ultrafast CT (n = 1) of the chest, MRI (n = 10), MRA (n = 1), contrast cineangiocardiography (n = 9), surgery (n = 11), or autopsy (n = 2). The salient clinical features were recurrent lung infections in 14 patients, acute respiratory distress in 13, associated cardiovascular malformations in 8, dextroversion in 7, congestive heart failure in 7, dextrocardia in 4, and complex congenital heart diseases in 4. There were abnormal openings (malinosculations) of the pulmonary airway in 20 patients: to an artery in 12, to a vein in 8, and to the lung parenchyma in 9. These 22 patients with congenital BPVM can be classified into bronchial malinosculation (10 cases), arterial malinosculation (2 cases), and bronchoarterial malinosculation (10 cases). Congenital BPVM can be classified in terms of bronchopulmonary malinosculation based upon a haphazard branching theory, in which abnormal communications between two independent systems (primitive foregut system and aortic-pulmonary arch system) occurred coincidentally rather than causally. 相似文献
84.
85.
Permissive herpes simplex virus (HSV) infection in tissue culture results in host cell destruction. Latent HSV infection in vivo occurs in neurons of peripheral sensory ganglia (PSG) and it therefore can not take place in neurons in which the virus has completed a lytic replication cycle similar to that present in vitro. Our hypothesis, based on experimental data and observations in humans, suggests that establishment of latent infection and reactivation of HSV-1 does not involve neuronal cell loss. Latency is established in neurons in which the virus does not replicate and is determined, in part, by the tissue levels of a herpes transactivating protein (Vmw65) that is a component of the viral tegument. We also suggest that reactivation of latent infection does not involve destruction of neurons and is due to replication of virus at the peripheral mucocutaneous tissues to where virus or viral DNA have been transported from the nervous tissue. Alternatively, reactivation is initiated in the PSG using a replication cycle which does not involve irreversible damage to neurons. This model explains the lack of damage to neurons which continue to serve as permanent reservoirs of latent virus for the entire life of the host. 相似文献
86.
87.
The effect of interleukin-1 on iron metabolism in rats was evaluated. Plasma iron decreased from 184 +/- 16 micrograms/dl (mean +/- SE) to 24 +/- 12 at 6 hours after interleukin-1 intramuscular administration in non-fasting rats and 109 +/- 6 micrograms/dl to 12 +/- 1 micrograms/dl in fasting rats, which was significantly lower than in control rats. Ferrokinetic studies showed a more rapid disappearance rate and lower iron turnover in interleukin-1-injected rats. The release of iron from the mononuclear phagocyte system to plasma was studied at 3 h after interleukin-1 administration. Although the percent of radioactivity in plasma of the total injected dose was 3.2 +/- 0.6% in interleukin-1, which was significantly lower than in the control rats (5.4 +/- 0.6%) at 9 h after intravenous injection of 59Fe chondroitin ferrous sulfate, there was no difference between the amount of 59Fe released from the mononuclear phagocyte system over the first 9 h in interleukin-1 and control rats. These data appear to imply that iron release is unimpaired but that, for some reason, there is an enhanced rate of clearance of the 59Fe once it has been released from the mononuclear phagocyte system into the plasma. 相似文献
88.
Ernst R. Kuse Joerg Kotzerke Silke Müller Björn Nashan Rainer Lück Karsten Jaeger 《Transplant international》2002,15(6):272-277
It has been demonstrated that total parenteral nutrition (TPN) modulates the function of the hepatic reticuloendothelial system (RES). The objective of this study was to evaluate the impact of two different TPN lipid emulsions on the recovery of allograft RES function after orthotopic liver transplantation (OLTx). In a prospective, double-blind study, OLTx patients were randomly assigned to two treatment groups. Group I ( n=13) received a TPN regimen that included long-chain triglycerides (LCT). Group II ( n=9) received a TPN regimen that included a fat emulsion consisting of both medium-chain triglycerides (MCT) and LCT. At baseline, i.e., on days 2 or 3 after OLTx ( t1), before lipids for TPN were started, hepatic RES function was determined using the human serum albumin millimicrosphere technique (K-value, 1/min). A second measurement ( t2) was obtained after 7 days of TPN, including one of the study's two fat emulsions. The mean (+/- SD) K-value (1/min) was 0.48+/-0.16 in the LCT group and 0.55+/-0.28 in the MCT/LCT group at t1, and it improved to 0.62+/-0.21 in the LCT group and to 0.86+/-0.32 in the MCT/LCT group at t2. RES function recovery was significantly better in the MCT/LCT group ( P< or = 0.05). MCT/LCT emulsion appears to be the TPN fat emulsion of choice after OLTx as it seems to have less impact on hepatic RES recovery. 相似文献
89.
90.
乳腺影像学报告及数据系统:超声良恶性病变鉴别诊断初探 总被引:1,自引:0,他引:1
1992年美国放射学会制定了乳腺影像学报告及数据系统(breast imaging reporting and data system,BI-RADS),2003年第四版修订时包括了超声诊断(BI-RADS-US)。本文旨在初步探讨BI-RADS-US对于乳腺良恶性病变鉴别诊断的能力。我们收集了2006年1月至2007年3月期间、获得病理诊断的乳腺占位性病变共69例72灶。均为女性,年龄14-83岁,平均41.6岁。首先根据一般的非BI-RADS标准,做出良恶性鉴别。然后用BI-RADS-US标准进行鉴别和分级(0-6级),其中2级和3级为良性和良性可能性大,4级为性质待定,5级为恶性可能性大。计算并比较上述两种方法的准确性、敏感性、特异性。结果在72病灶中,根据非BI-RADS标准,诊断为良性者40灶,符合病理诊断者38灶(95.0%),诊断为恶性者23灶,符合病理者18灶(78.3%);诊断为性质待定者9灶。根据BI-RADS-US标准和分级,2级和3级共有37灶,与病理结果符合者为36灶(97.2%);5级有31灶,与病理符合者为22灶(71.0%);4级有4灶。非BI-RADS和BI-RADS-US的准确性各为83.3%和81.9%(P=1.000),敏感性各为91.7%和95.8%(P=1.000),特异性各为79.2%和75.0%(P=0.754)。总之,第一版BI-RADS-US在乳腺良恶性病变鉴别诊断方面的初步应用表现出较高的敏感性,而与非BI-RADS方法比较则尚无明显差别。 相似文献