全文获取类型
收费全文 | 378489篇 |
免费 | 24833篇 |
国内免费 | 2806篇 |
专业分类
耳鼻咽喉 | 5188篇 |
儿科学 | 8206篇 |
妇产科学 | 10080篇 |
基础医学 | 53148篇 |
口腔科学 | 11825篇 |
临床医学 | 30095篇 |
内科学 | 78323篇 |
皮肤病学 | 8548篇 |
神经病学 | 27187篇 |
特种医学 | 13923篇 |
外国民族医学 | 82篇 |
外科学 | 60564篇 |
综合类 | 9956篇 |
现状与发展 | 1篇 |
一般理论 | 64篇 |
预防医学 | 17425篇 |
眼科学 | 9440篇 |
药学 | 30972篇 |
1篇 | |
中国医学 | 2194篇 |
肿瘤学 | 28906篇 |
出版年
2021年 | 2604篇 |
2019年 | 2719篇 |
2018年 | 4519篇 |
2017年 | 3433篇 |
2016年 | 3520篇 |
2015年 | 4019篇 |
2014年 | 5693篇 |
2013年 | 7372篇 |
2012年 | 10013篇 |
2011年 | 10195篇 |
2010年 | 6190篇 |
2009年 | 5839篇 |
2008年 | 9452篇 |
2007年 | 10282篇 |
2006年 | 10202篇 |
2005年 | 9269篇 |
2004年 | 8775篇 |
2003年 | 8518篇 |
2002年 | 8193篇 |
2001年 | 28280篇 |
2000年 | 28790篇 |
1999年 | 23666篇 |
1998年 | 5165篇 |
1997年 | 4248篇 |
1996年 | 3832篇 |
1995年 | 3481篇 |
1994年 | 3108篇 |
1993年 | 2846篇 |
1992年 | 16048篇 |
1991年 | 14816篇 |
1990年 | 14158篇 |
1989年 | 13965篇 |
1988年 | 12583篇 |
1987年 | 12064篇 |
1986年 | 11106篇 |
1985年 | 10328篇 |
1984年 | 6916篇 |
1983年 | 5601篇 |
1982年 | 2718篇 |
1979年 | 5481篇 |
1978年 | 3347篇 |
1977年 | 2972篇 |
1975年 | 2641篇 |
1974年 | 3065篇 |
1973年 | 2865篇 |
1972年 | 2831篇 |
1971年 | 2776篇 |
1970年 | 2515篇 |
1969年 | 2547篇 |
1968年 | 2253篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
1-乙基-6-氟-1,4-二氢-4-氧代-7-(4-芳酰硫代氨甲酰基-1-哌嗪基)-3-喹啉羧酸的合成及抗菌作用 总被引:4,自引:1,他引:3
Thirteen new 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-aroyl-thiocarbamoyl- 1 piperazinyl)-3-quinoline carboxylic acids were prepared, Their structures were characterized by elemental analysis, IR, HNMR and MS spectra.Preliminary pharmacological tests indicated that some of compounds Ia~m possess strong inhibiting activity against Escherichia coli, Bacillus subtilis and Proteus at concentration of 100 μg/ml. 相似文献
152.
T Oda N Yoshizawa S Oshima A Takeuchi T Kubota S Kondo Y Oshikawa Y Akashi Y Suzuki H Niwa 《Nihon Jinzo Gakkai shi》1990,32(6):631-641
To investigate the role of cell-mediated immunity (CMI) in glomerulonephritis (GN), we identified the infiltrating immune cells both within the glomerulus and in the interstitium. Frozen sections from 103 patients with various forms of GN: 10 with minor glomerular abnormality (MGA) as control, 10 with minimal change nephrotic syndrome (MCNS), 10 with membranous nephropathy (MN), 9 with focal glomerulosclerosis (FGS), 30 with IgA nephropathy (IgAN), 22 with acute post streptococcal glomerulonephritis (APSGN), and 2 with rapidly progressive glomerulonephritis (RPGN) were examined using monoclonal antibodies (MoAb) by indirect immunoalkaline-phosphatase labelling. In most glomerulonephritis, monocyte/M phi and helper/inducer T cells were predominantly infiltrating in the interstitium, but intraglomerular infiltration was rare, except for APSGN. This interstitial infiltration increased proportionally to the level of serum creatinine, and was most prominent in RPGN. Apparently different distribution was seen in APSGN, that is, prominent increase in total number of intra-glomerular monocyte/M phi infiltration with slightly increased T cells. The change was correlated with time after onset; namely the more leucocytic infiltration was observed when the tissue was taken earlier. These data suggest that in APSGN, monocyte/M phi accumulate in glomeruli via cell mediated immunity in addition to humoral immune mechanism resulting in glomerular hypercellularity, whereas in most chronic glomerulonephritis interstitial leucocyte infiltration, particularly helper T cells and monocyte/M phi may play an important role in the progression of glomerulonephritis. 相似文献
153.
154.
T Uno H Kondo Y Inoue Y Kawahata M Sotomura K Iuchi G Tsukamoto 《Journal of medicinal chemistry》1990,33(10):2929-2932
A series of novel pyridone carboxylic acids having a 4-hydroxypiperazinyl group at the 7-position of norfloxacin and ciprofloxacin were prepared. The in vivo antibacterial efficacies of these compounds were superior to those of corresponding piperazinyl derivatives. From the results of the studies on the pharmacokinetic profile and toxicity, the 4-hydroxypiperazinyl derivatives were confirmed to be pharmacologically superior to corresponding piperazinyl derivatives. Thus, a 4-hydroxypiperazinyl group was revealed to be a beneficial substituent for potential use in future quinolone antibacterials. 相似文献
155.
D Y Graham 《Mayo Clinic proceedings. Mayo Clinic》1988,63(12):1258-1260
Occurrence of C. pylori infection of mucosa outside of the stomach might provide an ideal opportunity to examine C. pylori-mucosal interactions apart from the effects of acid and pepsin. Techniques previously used to examine Barrett's epithelium (for example, special mucin stains or scanning and transmission electron microscopy) might be particularly useful for exploration of new associations and formulation of new hypotheses. Whether C. pylori has a role in development of Barrett's ulcer or adenocarcinoma as a complication of Barrett's esophagus remains unanswered. Most of the current data about C. pylori are primarily observational; further studies are needed for clarification of important microbegut interactions. 相似文献
156.
H Murakami M Togawa S Takahashi N Kasahara J Yamamoto N Matsuura Y Koshiyama Y Ino M Oda 《Arzneimittel-Forschung》1990,40(12):1352-1358
The effects of FUT-187 (6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate, CAS 103926-82-5), a novel synthetic protease inhibitor, were examined in experimental rat and canine models of pancreatitis. 1. FUT-187 significantly increased the survival of rats with trypsin- and phospholipase A2-induced pancreatitis in a dose-dependent manner (10-100 mg/kg, p.o.). 2. FUT-187 decreased plasma enzymatic activity reflecting the degree of pancreatitis in rats with ethionine-induced pancreatitis, and showed a tendency to ameliorate histopathological changes in the pancreas (10-100 mg/kg p.o.). 3. FUT-187 (10 mg/kg) produced an obvious improvement of various biochemical parameters of pancreatitis and also reduced histopathological changes in the pancreas in animals with experimental pancreatitis produced by the closed duodenal loop method. In addition, FUT-187 significantly increased the survival of dogs when given by direct administration into the lumen of the closed duodenal loop. The therapeutic effects of FUT-187 in experimental pancreatitis were nearly equal in most instances to those of camostat mesilate. Thus, FUT-187 would appear to be an effective new agent for the treatment of pancreatitis. 相似文献
157.
I Maeda T Ueda R Koide M Inatomi Y Fukado E Uchida K Oguchi H Yasuhara 《Japanese journal of ophthalmology》1988,32(2):211-218
The effects of monoamine oxidase-A (MAO-A) inhibitors with epinephrine on intraocular pressure in the pigmented rabbit were studied. MAO-A inhibitors were used topically with or without various concentrations of epinephrine. For the measurement of intraocular pressure, applanation pneumatonography was used and tissue MAO activities were determined by radiometric assay. After topical administration with clorgyline, MAO-A activities in the bulbar conjunctiva and the iris-ciliary body were remarkably inhibited, whereas MAO-B inhibition was minimal. Maximal reduction of intraocular pressure with 0.05% epinephrine was 3.2 mmHg. Single administration of clorgyline, amiflamine, moclobemide or CGP 11305-A caused decreases in the intraocular pressure of 2.0, 2.5, 1.8 and 2.4 mmHg, respectively. In the coadministration experiments with epinephrine, the ocular hypotensive effects of epinephrine were potentiated with clorgyline, amiflamine, moclobemide and CGP 11305-A (6.6, 4.8, 5.6 and 5.8 mmHg). On the contrary, they were not influenced by the MAO-B inhibitor deprenyl. These results indicated that MAO-A inhibitors potentiated the ocular hypotensive effects of epinephrine, and that the coadministration of a reversible MAO-A inhibitor with epinephrine might be useful for patients with glaucoma. 相似文献
158.
The YAG (yttrium aluminum garnet) laser has been recommended for anterior capsulotomies. One major complication is elevated intraocular pressure. We report a study of the biochemical content of the aqueous humor after a YAG laser anterior capsulotomy. We analyzed 6-keto-prostaglandin F1 alpha, thromboxane B2 and protein concentrations in the aqueous humor of human eyes. The average values of protein, 6-keto-prostaglandin F1 alpha, and thromboxane B2 in the control eyes were 81.3 +/- 14.0 mg/dL, 17 +/- 30 pg/mL, and 10 +/- 10 pg/mL, respectively. These values were elevated to 182.4 +/- 81.3 mg/dL, 401 +/- 55 pg/mL, and 576 +/- 148 pg/mL, respectively, after YAG laser anterior capsulotomy. The samples with a moderate level of 6-keto-prostaglandin F1 alpha (less than 300 pg/mL) had negligible changes of thromboxane. The elevation of thromboxane was obvious only when prostaglandin levels rose above 300 pg/mL. 相似文献
159.
160.
A G Antoshechkin L A Tatur VYuMaximova 《Clinica chimica acta; international journal of clinical chemistry》1988,177(3):239-244
In order to study metabolic distinctions in phenylketonuria, urinary metabolites in the form of trimethylsilyl derivatives have been characterized by high resolution gas chromatography and mass spectrometry. A previously unknown metabolite has been found in the urine of some untreated phenylketonuric infants between 2 and 5 yr of age. The metabolite was absent in healthy children of the same age. The metabolite appeared to be present in the urine of apparently healthy adults (25-32 yr old). The metabolite was identified as methoxyacetylcarbamide on the basis of mass fragmentation analysis and compared with synthetic methoxyacetylcarbamide. Their retention times and mass spectra coincided. 相似文献