全文获取类型
收费全文 | 12487篇 |
免费 | 598篇 |
国内免费 | 89篇 |
专业分类
耳鼻咽喉 | 181篇 |
儿科学 | 242篇 |
妇产科学 | 119篇 |
基础医学 | 1615篇 |
口腔科学 | 251篇 |
临床医学 | 739篇 |
内科学 | 3416篇 |
皮肤病学 | 164篇 |
神经病学 | 1067篇 |
特种医学 | 534篇 |
外科学 | 2265篇 |
综合类 | 48篇 |
一般理论 | 2篇 |
预防医学 | 296篇 |
眼科学 | 111篇 |
药学 | 708篇 |
中国医学 | 20篇 |
肿瘤学 | 1396篇 |
出版年
2024年 | 14篇 |
2023年 | 90篇 |
2022年 | 185篇 |
2021年 | 309篇 |
2020年 | 152篇 |
2019年 | 250篇 |
2018年 | 298篇 |
2017年 | 246篇 |
2016年 | 294篇 |
2015年 | 319篇 |
2014年 | 390篇 |
2013年 | 487篇 |
2012年 | 819篇 |
2011年 | 832篇 |
2010年 | 520篇 |
2009年 | 436篇 |
2008年 | 822篇 |
2007年 | 895篇 |
2006年 | 856篇 |
2005年 | 834篇 |
2004年 | 846篇 |
2003年 | 789篇 |
2002年 | 778篇 |
2001年 | 126篇 |
2000年 | 106篇 |
1999年 | 125篇 |
1998年 | 216篇 |
1997年 | 137篇 |
1996年 | 141篇 |
1995年 | 88篇 |
1994年 | 93篇 |
1993年 | 95篇 |
1992年 | 62篇 |
1991年 | 50篇 |
1990年 | 47篇 |
1989年 | 37篇 |
1988年 | 44篇 |
1987年 | 39篇 |
1986年 | 27篇 |
1985年 | 31篇 |
1984年 | 30篇 |
1983年 | 33篇 |
1982年 | 20篇 |
1981年 | 25篇 |
1980年 | 28篇 |
1978年 | 18篇 |
1977年 | 14篇 |
1976年 | 11篇 |
1975年 | 11篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Definition and pathology of primary sclerosing cholangitis 总被引:3,自引:1,他引:3
Nakanuma Y Harada K Katayanagi K Tsuneyama K Sasaki M 《Journal of Hepato-Biliary-Pancreatic Surgery》1999,6(4):333-342
Although primary sclerosing cholangitis (PSC) is not a common disease, it is important in the differential diagnosis of hepatobiliary
tract diseases in clinical practice. A diagnosis of PSC should be made only after the exclusion of similar diseases with well
known etiologies or pathogeneses. In this review, the pathology of classical PSC and its variants or related diseases is highlighted.
PSC is histologically characterized by progressive periductal fibrosis with luminal stenosis or obliteration, along with the
formation of a fibrous core, as well as dilatation (cholangiectasis). Its etiology is unknown. Bacterial ascending cholangitis
is superimposed on its long clinical course. Such a heterogeneous distribution of biliary lesions with biliary obliteration
and cholangiectasis is responsible for the radiological demonstration of biliary abnormalities, particularly the beaded appearance.
Sampling variability is common in needle or wedge biopsied specimens. As a result of biliary damage, the liver shows progressive
cholestatic change followed by biliary fibrosis and cirrhosis, and this hepatic progression is divisible into four stages.
There are several variants of PSC or related diseases, such as localized biliary sclerosis and stenosis, sclerosing cholangitis
associated with inflammatory pseudotumor, and PSC-autoimmune hepatitis overlapping syndrome. Cholelithiasis, including secondary
hepatolithiasis and, to a lesser degree, biliary carcinoma and dysplasia, are also known to develop at the perihilar bile
ducts as a late complication of PSC.
Received for publication on March 8, 1999; accepted on April 30, 1999 相似文献
73.
Katsuhiko Ogasawara Jun Hashimoto Koichi Ogawa Atsushi Kubo Nobutoku Motomura Hyoji Hasegawa Takashi Ichihara 《European journal of nuclear medicine and molecular imaging》1998,25(11):1537-1544
The aim of this study was to obtain quantitative iodine-123 brain single-photon emission tomographic (SPET) images with scatter
and attenuation correction. We used a triple-headed SPET gamma camera system equipped with fan-beam collimators with a technetium-99m
line transmission source placed at one of the focal lines of the fan-beam collimators. Four energy windows were employed for
data acquisition: (a) 126–132 keV, (b) 132–143 keV, (c) 143–175 keV and (d) 175–186 keV. A simultaneous transmission-emission
computed tomography scan (TCT-ECT) was carried out for a brain phantom containing 123I solution. The triple energy window scatter correction was applied to the 123I ECT data measured by means of the windows (b), (c) and (d) acquired by two detectors. Attenuation maps were reconstructed
from 99mTc TCT data measured by means of the windows (a), (b) and (c) acquired by one detector. Chang’s iterative attenuation correction
method using the attenuation maps was applied to the 123I ECT images. In the phantom study cross-calibrated SPET values obtained with the simultaneous mode were almost equal to those
obtained with the sequential mode, and they were close to the true value, within an error range of 5.5%. In the human study
corrected images showed a higher grey-to-white matter count ratio and relatively higher uptake in the cerebellum, basal ganglia
and thalamus than uncorrected images. We conclude that this correction method provides improved quantification and quality
of SPET images and that the method is clinically practical because it requires only a single scan with a 99mTc external source.
Received 6 June and in revised form 27 July 1998 相似文献
74.
75.
Shogo Kobayashi Hiroaki Nagano Shigeru Marubashi Koichi Kawamoto Hiroshi Wada Hidetoshi Eguchi Masahiro Tanemura Koji Umeshita Yuichiro Doki Masaki Mori 《Surgical endoscopy》2013,27(2):610-617
Purpose
This study was designed to evaluate the surgical parameters and treatment outcomes of tumor hemodynamics-based pure laparoscopic (PURE) and laparoscopy-assisted (HYBRID) hepatectomy for small hepatocellular carcinoma (HCC) compared with those of open hepatectomy.Methods
Using a prospectively collected database from 1997 to 2011, we analyzed the data of 56 consecutive cases of laparoscopic hepatectomy for HCC (PURE, n = 24; HYBRID, n = 29; HALS, n = 3) from among 102 cases undergoing laparoscopic hepatectomy. We employed 27 cases treated by open hepatectomy during the same period as controls.Results
PURE was associated with lesser blood loss, lower weight of the resected liver, and a shorter skin incision than HYBRID and open hepatectomy [median blood loss (mL): PURE 7, HYBRID 380, Open 450; P < 0.05]. On the other hand, HYBRID hepatectomy was associated with a longer operation time [operation time (min): HYBRID 232, Open 185; P = 0.0226]. The length of hospitalization in the cases treated by PURE and HYBRID hepatectomy was shorter than that in the cases treated by open hepatectomy [length of hospitalization (days): PURE 11, HYBRID 12, Open 17; P < 0.05]. One case each of transfusion and morbidity was recorded in this series. There was no significant difference of the overall (OS) or disease-free survival (DFS) between the patients treated by laparoscopic and open hepatectomy (3-year OS: 100 vs. 100 %; DFS 50 vs. 62 %, respectively).Conclusions
Neither the surgical parameters nor the treatment outcomes of hemodynamics-based laparoscopic hepatectomy were inferior to those of open hepatectomy. 相似文献76.
Tsurugaya H Toyama T Isobe N Hoshizaki H Oshima S Taniguchi K 《Kaku igaku. The Japanese journal of nuclear medicine》2002,39(4):477-484
PURPOSE: The aim of this study is to clarify the causes of exercise-induced ST-segment depression in patients with broad lateral old myocardial infraction involving LCX (LCX-OMI) without ischemia on exercise scintigraphy. METHOD: Twenty one patients (M/F = 11/10, age = 62 +/- 19 years) with myocardial infraction involving LCX (LCX-MI), but without fill-in on exercise and rest MIBI quantitative gated SPECT (QGS), were selected. They were divided into two groups of Group ST(+) (n = 11, with significant ST depression (max -2.8 +/- 0.4 mm), Group ST(-) (n = 10) without ST depression. On 20 SPECT segments of both exercise and rest SPECT, we scored uptake score as DS (0 = normal to 3 = defect) and wall motion as WMS (0 = normal to -5 = dyskinesis) and summed DS (TDS) and WMS (TWMS) in LCX region, furthermore, calculated the difference of TWMS (delta TWMS [exercise-rest]), end diastolic volume (EDV) and ejection fraction (EF) during exercise were compared between the two groups. RESULT: Group ST(+) showed significantly (p < 0.01) lower EF (35.4 +/- 9.2% vs. 60.2 +/- 6.2%), larger EDV (146 +/- 53 ml vs. 93 +/- 15 ml), higher TDS (5 vs. 7 +/- 3), lower TWMS (-25 +/- 9 vs. -6 +/- 5), furthermore lower delta TWMS (-6.9 +/- 4.0 vs. -2.0 +/- 0.8) than Group ST(-). CONCLUSION: Exercise-induced significant ST depression in V2-4 without ischema in LCX-MI was observed in patients with broad LCX-MI, low EF, and was related to impaired wall motion in LCX region. ST depression in V2-4 was considered to appear as miller image of ST elevation at postero-inferior wall due to disturbed wall motion on exercise. 相似文献
77.
Hiraki T Mimura H Kanazawa S Yasui K Dendo S Yoshimura K Okumura Y Hiraki Y 《Journal of vascular and interventional radiology : JVIR》2002,13(7):743-746
Aortobronchial fistula is a fatal complication after thoracic aortic surgery. So far, treatment options for aortobronchial fistula have included surgical and endovascular stent-graft methods. Herein, a case of an aortobronchial fistula with life-threatening hemoptysis managed with transcatheter embolization of the fistula with N-butyl cyanoacrylate is reported. For the patient with an aortobronchial fistula who cannot be treated by surgical or endovascular stent-graft methods, transcatheter embolization of the fistula may be the only available life-saving method. 相似文献
78.
Correction of nonuniform attenuation and image fusion in SPECT imaging by means of separate X-ray CT
Kashiwagi T Yutani K Fukuchi M Naruse H Iwasaki T Yokozuka K Inoue S Kondo S 《Annals of nuclear medicine》2002,16(4):255-261
Improvements in image quality and quantitation measurement, and the addition of detailed anatomical structures are important topics for single-photon emission tomography (SPECT). The goal of this study was to develop a practical system enabling both nonuniform attenuation correction and image fusion of SPECT images by means of high-performance X-ray computed tomography (CT). A SPECT system and a helical X-ray CT system were placed next to each other and linked with Ethernet. To avoid positional differences between the SPECT and X-ray CT studies, identical flat patient tables were used for both scans; body distortion was minimized with laser beams from the upper and lateral directions to detect the position of the skin surface. For the raw projection data of SPECT, a scatter correction was performed with the triple energy window method. Image fusion of the X-ray CT and SPECT images was performed automatically by auto-registration of fiducial markers attached to the skin surface. After registration of the X-ray CT and SPECT images, an X-ray CT-derived attenuation map was created with the calibration curve for 99mTc. The SPECT images were then reconstructed with scatter and attenuation correction by means of a maximum likelihood expectation maximization algorithm. This system was evaluated in torso and cylindlical phantoms and in 4 patients referred for myocardial SPECT imaging with Tc-99m tetrofosmin. In the torso phantom study, the SPECT and X-ray CT images overlapped exactly on the computer display. After scatter and attenuation correction, the artifactual activity reduction in the inferior wall of the myocardium improved. Conversely, the incresed activity around the torso surface and the lungs was reduced. In the abdomen, the liver activity, which was originally uniform, had recovered after scatter and attenuation correction processing. The clinical study also showed good overlapping of cardiac and skin surface outlines on the fused SPECT and X-ray CT images. The effectiveness of the scatter and attenuation correction process was similar to that observed in the phantom study. Because the total time required for computer processing was less than 10 minutes, this method of attenuation correction and image fusion for SPECT images is expected to become popular in clinical practice. 相似文献
79.
Anraku M Yokoi K Nakagawa K Fujisawa T Nakajima J Akiyama H Nishimura Y Kobayashi K;Metastatic Lung Tumor Study Group of Japan 《The Journal of thoracic and cardiovascular surgery》2004,127(4):1107-1112
OBJECTIVE: The long-term results of the surgical treatment for patients with pulmonary metastases from uterine malignancies were clarified. METHODS: A total of 133 patients who underwent pulmonary metastasectomy for uterine malignancies were enrolled in the Metastatic Lung Tumor Study Group of Japan between March 1984 and February 2002. These patients constituted the study population, and their clinical, pathologic, and prognostic data were retrospectively analyzed. RESULTS: The morbidity and mortality rates related to the operation were minimal (1% and 1%, respectively). The 5- and 10-year survivals after the surgical resection in all cases were 54.6% and 44.9%, respectively. The 5-year survivals for each histologic type were estimated to be 46.8% for squamous cell carcinoma (n = 58), 40.3% for cervical adenocarcinoma (n = 13), 75.7% for endometrial adenocarcinoma (n = 23), 86.5% for choriocarcinoma (n = 16), and 37.9% for leiomyosarcoma (n = 11). In the univariate analysis, the following were shown to be associated with poor survival: primary tumor in the cervix, short disease-free interval (<12 months), large number of resected metastases (> or =4), and large tumor size (> or =3 cm). After mutual adjustment, short disease-free interval (<12 months) alone was related to risk of death (hazard ratio = 2.26, 95% confidence interval = 1.06-4.78) for 105 patients, excluding patients with choriocarcinoma and miscellaneous histologic types. CONCLUSION: Pulmonary metastasectomy for uterine malignancies is a safe and acceptable treatment to improve survival. Patients with a disease-free interval of 12 months or more are good candidates for this treatment if there is adequate control of the primary tumor without extrapulmonary metastasis. 相似文献
80.
Osada D Fujita S Tamai K Iwamoto A Tomizawa K Saotome K 《The Journal of hand surgery》2004,29(3):446-451
PURPOSE: A new fixed-angle volar plate for a dorsally displaced distal radius fracture was designed with the aim of avoiding soft tissue problems due to dorsal plating. The purpose of this study was to compare the biomechanical properties of this new plate with 2 existing volar plates in a cadaver model. METHODS: Three different plates were applied on surgically simulated unstable extra-articular distal radius fractures in formalin-fixed cadaver radiuses. Group 1 (volarly placed AO titanium Distal Radius plates [Synthes Ltd, Paoli, PA]; n = 6), group 2 (volarly placed titanium Symmetry plates [DePuy ACE Co, El Segundo, CA]; n = 6), and group 3 (volarly placed newly designed titanium plates; n = 6) were tested to failure under axial compression with a materials testing machine. Specimens of all 3 groups had similar bone mineral density. RESULTS: Group 3 specimens had significantly greater elastic limit and ultimate strength than the other 2 groups. Specimens of group 3 had the greatest rigidity, although this was statistically insignificant compared with the other 2 groups. All plates (groups 1, 2, 3) failed in apex volar angulation. CONCLUSIONS: The newly designed plate fixation system is the strongest of the systems tested and may offer adequate stability for the treatment of a distal radius fracture in which the dorsal and/or volar metaphyseal cortex is comminuted severely. 相似文献