全文获取类型
收费全文 | 17185篇 |
免费 | 907篇 |
国内免费 | 122篇 |
专业分类
耳鼻咽喉 | 259篇 |
儿科学 | 351篇 |
妇产科学 | 200篇 |
基础医学 | 2207篇 |
口腔科学 | 494篇 |
临床医学 | 1072篇 |
内科学 | 4768篇 |
皮肤病学 | 265篇 |
神经病学 | 1179篇 |
特种医学 | 576篇 |
外科学 | 2745篇 |
综合类 | 55篇 |
预防医学 | 491篇 |
眼科学 | 288篇 |
药学 | 1188篇 |
中国医学 | 39篇 |
肿瘤学 | 2037篇 |
出版年
2023年 | 119篇 |
2022年 | 238篇 |
2021年 | 379篇 |
2020年 | 197篇 |
2019年 | 265篇 |
2018年 | 321篇 |
2017年 | 293篇 |
2016年 | 329篇 |
2015年 | 363篇 |
2014年 | 422篇 |
2013年 | 573篇 |
2012年 | 957篇 |
2011年 | 1024篇 |
2010年 | 566篇 |
2009年 | 528篇 |
2008年 | 877篇 |
2007年 | 975篇 |
2006年 | 968篇 |
2005年 | 966篇 |
2004年 | 919篇 |
2003年 | 919篇 |
2002年 | 861篇 |
2001年 | 433篇 |
2000年 | 447篇 |
1999年 | 427篇 |
1998年 | 228篇 |
1997年 | 187篇 |
1996年 | 161篇 |
1995年 | 125篇 |
1994年 | 113篇 |
1993年 | 116篇 |
1992年 | 308篇 |
1991年 | 235篇 |
1990年 | 242篇 |
1989年 | 219篇 |
1988年 | 222篇 |
1987年 | 201篇 |
1986年 | 206篇 |
1985年 | 178篇 |
1984年 | 123篇 |
1983年 | 110篇 |
1981年 | 51篇 |
1980年 | 48篇 |
1979年 | 89篇 |
1978年 | 69篇 |
1977年 | 46篇 |
1974年 | 67篇 |
1972年 | 52篇 |
1970年 | 47篇 |
1969年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Chie Teramoto PHN RN MS Satoko Nagata PhD PHN RN Reiko Okamoto PhD PHN RN Ruriko Suzuki PHN RN MS Emiko Kishi PhD PHN RN Michie Nomura DSN PHN RN Noriko Jojima PHN RN MS Masumi Nishida PhD PHN RN Keiko Koide PhD PHN RN Emiko Kusano PhD PHN RN Saori Iwamoto PhD PHN RN Sachiyo Murashima PhD PHN RN 《Public health nursing (Boston, Mass.)》2015,32(6):654-661
2.
3.
4.
Akira Sawaki Nobumasa Mizuno Kuniyuki Takahashi Tsuneya Nakamura Masahiro Tajika Hiroki Kawai Toshifumi Isaka Hiroshi Imaoka Yasuyuki Okamoto Masatoshi Aoki Hiroyuki Inoue Ahmed AS Salem Yasushi Yatabe Kenji Yamao 《Digestive endoscopy》2006,18(1):40-44
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed. 相似文献
5.
Sami S Zoghbi H Umesha Shetty Masanori Ichise Masahiro Fujita Masao Imaizumi Jeih-San Liow Jay Shah John L Musachio Victor W Pike Robert B Innis 《Journal of nuclear medicine》2006,47(3):520-527
18F-2beta-Carbomethoxy-3beta-(4-chlorophenyl)-8-(2-fluoroethyl)nortropane (18F-FECNT), a PET radioligand for the dopamine transporter (DAT), generates a radiometabolite that enters the rat brain. The aims of this study were to characterize this radiometabolite and to determine whether a similar phenomenon occurs in human and nonhuman primate brains by examining the stability of the apparent distribution volume in DAT-rich (striatum) and DAT-poor (cerebellum) regions of the brain. METHODS: Two rats were infused with 18F-FECNT and sacrificed at 60 min. Extracts of brain and plasma were analyzed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometric (LC-MS) techniques. Two human participants and 3 rhesus monkeys were injected with 18F-FECNT and scanned kinetically, with serial arterial blood analysis. RESULTS: At 60 min after the injection of rats, 18F-FECNT accumulated to levels about 7 times higher in the striatum than in the cortex and cerebellum. The radiometabolite was distributed at equal concentrations in all brain regions. The LC-MS techniques identified N-dealkylated FECNT as a major metabolite in the rat brain, and reverse-phase HPLC detected an equivalent amount of radiometabolite eluting with the void volume. The radiometabolite likely was 18F-fluoroacetaldehyde, the product expected from the N-dealkylation of 18F-FECNT, or its oxidation product, 18F-fluoroacetic acid. The distribution volume in the cerebellum increased up to 1.7-fold in humans between 60 and 300 min after injection and 2.0 +/- 0.1-fold (mean +/- SD; n = 3) in nonhuman primates between 60 and 240 min after injection. CONCLUSION: An 18F-fluoroalkyl metabolite of 18F-FECNT originating in the periphery confounded the measurements of DAT in the rat brain with a reference tissue model. Its uniform distribution across brain regions suggests that it has negligible affinity for DAT (i.e., it is an inactive radiometabolite). Consistent with the rodent data, the apparent distribution volume in the cerebellum of both humans and nonhuman primates showed a continual increase at late times after injection, a result that may be attributed to entry of the radiometabolite into the brain. Thus, reference tissue modeling of 18F-FECNT will be prone to more errors than analysis with a measured arterial input function. 相似文献
6.
Masanori Murakami Haruhiko Okada Masahiko Nishida Kimikazu Hamano 《Annals of thoracic and cardiovascular surgery》2006,12(3):216-218
A 14-year-old boy had a needle accidentally inserted through his chest wall. Chest X-ray showed a needle-shaped metallic density localized in the cardiac silhouette. An echocardiography indicated the needle had passed through the interventricular septum, and its eye and point had reached the right and left ventricle, respectively. Surgical removal of the needle was performed. The needle could not be observed from the heart surface, and was recognized in a dent 5 mm on the right side from the left anterior descending branch (LAD). The needle was easily removed under extracorporeal circulation, and he was discharged ten days after the operation. 相似文献
7.
Biological activity of partially purified digitalis-like substance and Na-K-ATPase inhibitor in rats
T Morise S Okamoto H Takasaki M Ikeda R Takeda F Kiuti Y Tuda 《Japanese circulation journal》1988,52(11):1309-1316
In order to study the biological activity of endogenous digitalis-like substance (DLS) and Na-K-ATPase inhibitor (ATPI), human urine was partially purified and administered to rats, and its effects on the urinary volume, urinary Na excretion and blood pressure (BP) were determined. In addition, the effect on myocardial Na-K-ATPase activity was also measured. After the extraction of 40L of urine with a reversed phase cartridge column (S-fraction), 20 ml of chloroform was added and extraction was repeated. The chloroform layer was applied to an open silica gel column, and at a fraction with ethylacetate: methanol (60: 40, T-1 fraction), DLS and ATPI were eluted at the highest concentration. The water layer was treated with charcoal (D-1 fraction). The acute administration of K-1, T-1 fraction to rats in vivo caused significant rises in urinary volume, urinary Na excretion and BP. In chronic administration of K-1 fraction, urinary Na excretion was significantly elevated and myocardial Na-K-ATPase activity was also significantly suppressed. These results suggest that DLS and ATPI cause increase in the urinary volume and urinary Na excretion and also possess a hypertensive action; and moreover, these substance may affect the heart like cardiotonic steroids and regulate BP by increasing cardiac contractility. 相似文献
8.
9.
Stimulation of the vagal trunk in cats anesthetized with pentobarbital sodium produced a contractile response of the stomach during stimulation (initial contraction). Pretreatment with either hexamethonium (0.3 to 30 mg/kg, i.v.) or gallamine (1 to 100 mg/kg, i.v.) dose-dependently produced a delayed contraction, following the initial contraction after stimulation. After the administration of either hexamethonium or gallamine produced a maximum delayed contraction, then an additional dose of gallamine or hexamethonium was administered. The subsequent treatment further augmented the delayed contraction. The results indicate that gallamine induced the delayed contraction by a mechanism different from hexamethonium. 相似文献
10.
T Tanaka T Aizawa K Katou K Ogasawara H Kirigaya K Okamoto 《Kaku igaku. The Japanese journal of nuclear medicine》1991,28(1):83-90
The patient responded to treatment at the first onset of heart failure but gradually became irresponsive to treatment, experiencing fatigue and malaise as the chief complaints and suffering from gradually progressive decrease in exercise capacity and body weight. Dose of DOA gradually increased to maintain well clinical state of the patient. Unusual for heart failure, he had bradycardia as the basal rhythm without showing a tendency for tachycardia. Cardiac catheterization revealed pulmonary hypertension and low cardiac output, however, left ventricular ejection fraction was 37%. There were no notable changes in ultrasonic cardiogram or CTR through the clinical course. Tl-201 myocardial images and pulmonary perfusion images showed gradual worsening corresponding to progressive worsening of clinical state. From these findings, the patient was determined as a candidate for heart transplantation. 相似文献