全文获取类型
收费全文 | 6294篇 |
免费 | 438篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 195篇 |
妇产科学 | 318篇 |
基础医学 | 813篇 |
口腔科学 | 195篇 |
临床医学 | 724篇 |
内科学 | 1237篇 |
皮肤病学 | 121篇 |
神经病学 | 386篇 |
特种医学 | 178篇 |
外科学 | 857篇 |
综合类 | 176篇 |
一般理论 | 2篇 |
预防医学 | 274篇 |
眼科学 | 203篇 |
药学 | 525篇 |
中国医学 | 88篇 |
肿瘤学 | 420篇 |
出版年
2023年 | 47篇 |
2022年 | 65篇 |
2021年 | 150篇 |
2020年 | 85篇 |
2019年 | 143篇 |
2018年 | 183篇 |
2017年 | 115篇 |
2016年 | 130篇 |
2015年 | 193篇 |
2014年 | 210篇 |
2013年 | 306篇 |
2012年 | 535篇 |
2011年 | 475篇 |
2010年 | 241篇 |
2009年 | 236篇 |
2008年 | 419篇 |
2007年 | 371篇 |
2006年 | 378篇 |
2005年 | 315篇 |
2004年 | 295篇 |
2003年 | 248篇 |
2002年 | 198篇 |
2001年 | 168篇 |
2000年 | 199篇 |
1999年 | 121篇 |
1998年 | 37篇 |
1997年 | 52篇 |
1996年 | 35篇 |
1995年 | 19篇 |
1994年 | 25篇 |
1993年 | 21篇 |
1992年 | 112篇 |
1991年 | 82篇 |
1990年 | 80篇 |
1989年 | 63篇 |
1988年 | 64篇 |
1987年 | 48篇 |
1986年 | 41篇 |
1985年 | 43篇 |
1984年 | 32篇 |
1983年 | 18篇 |
1982年 | 20篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 17篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1973年 | 9篇 |
1971年 | 12篇 |
1970年 | 12篇 |
排序方式: 共有6770条查询结果,搜索用时 281 毫秒
101.
Lu Y Huang CY Lin YF Wen ZH Su JH Kuo YH Chiang MY Sheu JH 《Journal of natural products》2008,71(10):1754-1759
Four new cembranoids, querciformolides A-D (1-4), along with two known cembranoids, 7 and 8, have been isolated from the soft coral Sinularia querciformis. Furthermore, chemical investigation of Sinularia granosa has afforded three new cembranoids, querciformolide B (2) and granosolides A (5) and B (6). The structures of the new metabolites were elucidated on the basis of extensive spectroscopic methods, and that of 2 was further confirmed by X-ray diffraction analysis. The absolute configurations of 1 and 2 were determined by a modified Mosher's method. Among these metabolites, 2-6 are rarely found cembranoids possessing a tetrahydrofuran moiety with a 4,7-ether linkage; in addition, 1 is the first epsilon-lactone cembrane found that possesses a tetrahydropyran moiety with a 4,8-ether linkage. None of these compounds were found to be cytotoxic toward a limited panel of cancer cell lines. However, compounds 3, 7, and 8 significantly inhibited the accumulation of the pro-inflammatory iNOS and COX-2 proteins in LPS-stimulated RAW264.7 macrophage cells. 相似文献
102.
S T Chiang P Y Lee S Y Liu 《Respiration; international review of thoracic diseases》1980,39(2):105-113
Pulmonary function was studied in a patient with Pickwickian syndrome, before and after a weight reduction of 160 kg which was brought about by jejunoileal bypass surgery. After weight reduction, there was an increase in alveolar ventilation, lung volumes and respiratory flow rates. Arterial blood oxygen tension, arterial oxygen saturation, arterial carbon dioxide tension and pH also showed a significant improvement towards normal. These findings indicate that reduction of body weight is beneficial for Pickwickian syndrome patients. The improvement of pulmonary function was probably due to the improvement of the patient's respiratory mechanics. 相似文献
103.
Effects of Cadmium and Phenol on Motility and Ultrastructure of Sea Urchin and Mussel Spermatozoa 总被引:8,自引:0,他引:8
Computer-assisted sperm analysis (CASA) was used to study the effects of Cd(II) and phenol on sperm motility of sea urchin
and mussel. In parallel, ultrastructural changes of sperm induced by these two toxicants were also investigated and related
to motility impairment. Spermatozoa of sea urchin were more sensitive than mussel spermatozoa to both toxicants. Sea urchin
sperm motility showed a good dose-response relationship to Cd(II) levels as well as exposure time. Exposure to the two toxicants
changed the size and shape of the midpiece, which might affect the balance of spermatozoa in their swimming. The plasma membrane
became more convoluted, and such a change might affect the streamlining and integrity of spermatozoa and hinder their normal
movement patterns. Most important, disorganization of mitochondrial membranes and cristae was observed, suggesting disruption
of ATP supply for sperm movement. Cadmium also induced greater ultrastructural damages in sea urchin spermatozoa.
Received: 8 March 1999/Accepted: 29 September 1999 相似文献
104.
Shih-Chang Chang Hui-Hsun Chiang Chih-Yi Liu Yu-Ju Li Chung-Lun Lu Yung-Pin Lee Chi-Jung Huang Ching-Long Lai 《Nutrients》2022,14(11)
Use of prebiotics is a growing topic in healthcare. A lightweight molecule and water-soluble fiber ingredient, longish glucomannan hydrolysates (LGH), has been developed to improve the intestinal mucosal barrier and confer gut health benefits. This study aims to investigate the implications of continuous LGH intervening in intestinal epithelium integrity and protective immunity against chemical dextran sodium sulfate (DSS)-induced colitis. Twelve male BALB/c mice were randomly arranged into four groups. The LGH/DSS group had results in bodyweight variance, epithelial cell density, and aberrancy score as good as the LGH group, and both were equivalent to the control group. LGH consumption effectively protects the distal intestinal epithelium by activating innate T lymphocytes. Meanwhile, T-cell subsets in subepithelial interspersion take a bystander role in these microenvironmental alterations. Under this stress, the cluster of differentiation 3 (CD3)+ T cells infiltrate the epithelium, while CD4+ T cells inversely appear in submucosal large lymphoid aggregates/isolated lymphoid follicles (ILFs) in which significant CD3+, CD4+, and CD8+ T-cell populations agglomerate. Moreover, forkhead box P3 (Foxp3) and interleukin 17 (IL-17) are observed in these ILFs. Agglomerated CD4+ T-cell lineages may have roles with proinflammatory T helper 17 cells and anti-inflammatory regulatory T cells in balancing responses to intraluminal antigens. Collectively, LGH administration may function in immune modulation to protect against DSS-induced inflammation. 相似文献
105.
G A Miura P K Chiang R K Gordon B P Doctor C E Twine A Philip J A Kepler F I Carroll 《General pharmacology》1986,17(4):477-480
Diethylaminoethyl acetate, an acetylcholine analog, was formed upon the incubation of diethylaminoethanol and acetyl-CoA with bovine brain choline acetyltransferase (acetyl-CoA: choline O-acetyltransferase; EC 2.3.1.6). The new product co-chromatographed with authentic diethylaminoethyl acetate on thin layer plates, and its formation was proportional to the duration of incubation and enzyme concentrations. When tested on guinea-pig ileum, diethylaminoethyl acetate was found to be an agonist with an ED50 of 1.3 X 10(-4) M, compared to an ED50 of 2.0 X 10(-7) M for acetylcholine. The contraction of guinea-pig ileum induced by diethylaminoethyl acetate was blocked by atropine. Moreover, diethylaminoethyl acetate induced a secretion of alpha-amylase from isolated pancreatic acini cells; this effect was also blocked by atropine. It is entirely possible that diethylaminoethyl acetate can be a false cholinergic transmitter generated in vivo when drugs such as aprophen or procaine are administered to animals, since either of these drugs can undergo enzymatic hydrolysis to generate diethylaminoethanol. A method for the synthesis of radioactive diethylamino [1,2-14C]ethyl acetate was also described. 相似文献
106.
Shih-Hung Yang Nai-Jung Chiang Sz-Chi Chiu Wen-Chi Chou Li-Yuan Bai Chung-Pin Li Yung-Yeh Su Tai-Jan Chiu Shih-Chang Chuang Cheng-Ming Peng De-Chuan Chan Jen-Shi Chen Chia-Jui Yen Yen-Yang Chen Chang-Fang Chiu Li-Tzong Chen Yan-Shen Shan 《American journal of cancer research》2022,12(4):1884
Nanoliposomal irinotecan (nal-IRI) plus 5-fluorouracil and leucovorin (NalFL) comprises the current standard for gemcitabine-failed metastatic pancreatic ductal adenocarcinoma (PDAC). As liposomes generally accumulate in the spleen, we evaluated the impact of spleen volume on prognosis. We enrolled patients with metastatic PDAC who failed gemcitabine-based therapy and were initiated on NalFL between August 2018 and November 2020. The spleen volume before NalFL administration was evaluated. They were stratified into dose subgroups (i.e. low, < 48 mg/m2; intermediate, 48 - < 64 mg/m2; high, ≥ 64 mg/m2) by the average nal-IRI dose during the entire treatment, and multivariate analysis of overall survival (OS) was performed. We included 547 patients with a median age of 63 years (range, 27-89 years) and a median of 1 (range, 0-7) palliative chemotherapy regimen. The median spleen volume was 245 mL (range, 82-817 mL). Among patients with splenomegaly (≥ 245 mL), the low-dose subgroup had the worst median time to treatment failure (TTF, 1.8 months vs. 2.5 months vs. 2.5 months, P = 0.020) and OS (3.3 months vs. 5.9 months vs. 6.6 months, P = 0.018) as against no prognostic impact in patients without splenomegaly. In the multivariate analysis of patients with splenomegaly, performance status (PS) ≥ 2, body surface area (BSA) < 1.6 m2, prior fluoropyrimidine use, liver metastasis, and low-dose subgroup were independent poor prognostic factors. A low average nal-IRI dose was significantly associated with poor prognosis, especially among patients with splenomegaly. Further pharmacological studies should validate the relevance of spleen volume on the treatment outcomes of nal-IRI. 相似文献
107.
108.
109.
110.
Pi-Ying Chang Che-Wei Wu Hsiu-Ya Chen Hui-Chun Chen Kuang-I Cheng I-Cheng Lu Feng-Yu Chiang 《The Kaohsiung journal of medical sciences》2014,30(10):499-503
Limited reports are available in the literature on the impact of intravenous administration of anesthetics on laryngeal electromyographic (EMG) activity. The purpose of this study was to determine the influence of the two commonly used intravenous anesthetics (propofol and thiamylal) on EMG amplitude evoked from the recurrent laryngeal nerve (RLN) during thyroid surgery. A total of 40 patients were randomized to receive a bolus of propofol (0.5 mg/kg; n = 20) or thiamylal (1.5 mg/kg; n = 20) to increase anesthetic depth when the surgeon found patient movement intraoperatively. Evoked potentials were obtained before and every 1 minute after the administration of each agent for up to 5 minutes by stimulating the RLN. The magnitude of evoked potentials at each time point and hemodynamic response were compared within groups. The mean amplitude of evoked potentials did not change significantly after administration of either propofol or thiamylal (p > 0.05 within groups). Mean arterial pressure measured from 1 minute to 5 minutes was significantly lower in the propofol group than in the thiamylal group (p < 0.05). Heart rate measured within 5 minutes did not differ significantly within groups. Low dose of propofol (0.5 mg/kg) or thiamylal (1.5 mg/kg) did not affect EMG readings during neuromonitoring of the RLN in thyroid surgery. Our results show that thiamylal provides better hemodynamic stability than propofol, and is therefore a preferable agent to increase anesthesia depth and prevent further patient movement during intraoperative neuromonitoring. 相似文献