全文获取类型
收费全文 | 2276篇 |
免费 | 114篇 |
国内免费 | 11篇 |
专业分类
2401篇 |
出版年
2024年 | 7篇 |
2023年 | 47篇 |
2022年 | 41篇 |
2021年 | 63篇 |
2020年 | 46篇 |
2019年 | 45篇 |
2018年 | 89篇 |
2017年 | 74篇 |
2016年 | 102篇 |
2015年 | 70篇 |
2014年 | 108篇 |
2013年 | 173篇 |
2012年 | 135篇 |
2011年 | 172篇 |
2010年 | 101篇 |
2009年 | 77篇 |
2008年 | 108篇 |
2007年 | 99篇 |
2006年 | 100篇 |
2005年 | 119篇 |
2004年 | 121篇 |
2003年 | 139篇 |
2002年 | 70篇 |
2001年 | 63篇 |
2000年 | 61篇 |
1999年 | 49篇 |
1998年 | 8篇 |
1997年 | 15篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1988年 | 12篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1966年 | 2篇 |
1965年 | 2篇 |
排序方式: 共有2401条查询结果,搜索用时 0 毫秒
41.
Summary. L-Tryptophan (TRP) is the precursor amino acid for the synthesis of serotonin (5-HT). 5-HT is effective both on the food intake
and gastrointestinal system contractility. The aim of this study was to search the effects of systemic TRP treatment on 5-HT
levels of ileum and searching the effect of ileal contractility and oxidant status. Swiss-albino mice were divided into two
groups: 1. Control, 2. TRP-treated (100 mg/kg/24 h, i.p., for 7 days). Body weights were recorded at the beginning and at
the end of experiments. Acetylcholine-induced contractile responses in the isolated ileum were recorded on polygraph. Ileal
tissue malondialdehyde and glutathione levels determined by spectrophotometric and ileal tissue 5-HT levels were measured
by immunohistochemical methods. TRP treatment decreased body weight and increased ileal contractile response. In the TRP-treated
group, ileum malondialdehyde levels increased and glutathione levels decreased. Immunohistochemical detection showed that
ileal 5-HT levels were increased by TRP treatment. There is a relationship between increased oxidative stress and increased
contractility in the ileal tissue of the TRP-treated animals. These effects may be related to increased ileal 5-HT synthesis. 相似文献
42.
Havva Balseven M. Mustafa İşgör Samet Mert Zuhal Alım Şükrü Beydemir Salim Ok Rahmi Kasımoğulları 《Bioorganic & medicinal chemistry》2013,21(1):21-27
In the current study, a series of pyrazole-sulfonamide derivatives (2–14) were synthesized, characterized, and the inhibition effects of the derivatives on human carbonic anhydrases (hCA I and hCA II) were investigated as in vitro. Structures of these sulfonamides were confirmed by FT-IR, 1H NMR, 13C NMR and LC–MS analysis. 1H NMR and 13C NMR revealed the tautomeric structures. hCA I and hCA II isozymes were purified from human erythrocytes and inhibitory effects of newly synthesized sulfonamides on esterase activities of these isoenzymes have been studied. The Ki values of compounds were 0.062–1.278 μM for hCA I and 0.012–0.379 μM for hCA II. The inhibition effects of 7 for hCA I and 4 for hCA II isozymes were almost in nanomolar concentration range. 相似文献
43.
44.
Demir Z Kurtay A Sahin U Velidedeoğlu H Celebioğlu S 《Plastic and reconstructive surgery》2003,112(2):423-429
Loss of mustache and beard in the adult male caused by severe burn, trauma, or tumor resection may cause cosmetic and psychological problems for these patients. Reconstruction of the elements of the face presents difficult and often daunting problems for plastic surgeons. The tissue that will be used for this purpose should have the same characteristics as the facial area, consisting of thin, pliable, hair-bearing tissue with a good color match. There is a very limited amount of donor area that has these characteristics. A hair-bearing submental island flap was used successfully for mustache and beard reconstruction in 11 male patients during the last 5 years. The scar was on the mentum in four cases, right cheek in two cases, right half of the upper lip in two cases, left cheek in one case, left half of the upper lip in one case, and both sides of the upper lip in one case. The submental island flap is supplied by the submental artery, a branch of the facial artery. The maximum flap size was 13 x 6 cm and the minimum size was 6 x 3 cm (average, 10 x 4 cm) in this series. Direct closure was achieved at all donor sites. Patients were followed up for 6 months to 5 years. No major complication was noted other than one case of temporary palsy of the marginal mandibular branch of the facial nerve. The mean postoperative stay was 7 days. Color and texture match were good. Hair growth on the flap was normal, and characteristics of the hair were the same as the intact side of the face in all patients. The submental island flap is safe, rapid, and simple to raise and leaves a well-hidden donor-site scar. The authors believe that the submental artery island flap surpasses the other flaps in reconstruction of the mustache and beard in male patients. Application of the technique and results are discussed in this article. 相似文献
45.
46.
An amperometric multienzyme biosensor for determination of triglycerides (TGs) was constructed by mounting three gelatin membrane-bound enzymes on a glassy carbon electrode (working electrode), then connecting it to electrometer along with an Ag/AgCl reference electrode and a Pt auxiliary electrode. Characterization and optimization of the multienzyme biosensor, which is prepared with glycerol kinase (GK) (E.C.2.7.1.30), glycerol-3-phosphate oxidase (GPO) (EC 1.1.3.21), and lipase (EC 3.1.1.3), were studied. In the optimization studies for the bioactive layer components of the prepared biosensor, the optimum amounts of gelatin, bovine serum albumin (BSA), and glutaraldehyde was calculated as 1 mg/cm2, 1 mg/cm2, and 2.5%, respectively. Optimum pH and temperature of the reaction of biosensor were determined as 7.0 and 40°C, respectively. Linear range of triolein for the biosensor was found from the calibration curve between several substrate concentration and Δ Current. After optimization and characterization of the biosensor, its operationability in triglycerides was also tested. 相似文献
47.
48.
Emrah Hicazi Aksu Fatih Mehmet Kandemir Serdar Altun Sefa Küçükler Selim Çomaklı Ali Doğan Ömür 《Journal of biochemical and molecular toxicology》2016,30(10):513-520
Cisplatin (CP) treatment causes the damage in male reproductive system. Carvacrol (CARV) is an antioxidant that is naturally found in some plants. We aimed to investigate the effect of CARV on CP‐induced reproductive toxicity in male rats. Eighteen adult male Sprague–Dawley rats were used. The control group (n = 6) was treated orally with physiological saline (PS) daily for 14 days and a single intraperitoneal (IP) PS injection on day 10. The CP group (n = 6) was administered with daily oral PS for 14 days and a single IP injection of 10 mg/kg CP on day 10. The CARV + CP group (n = 6) was treated with daily 75 mg/kg oral CARV for 14 days and a single IP injection of 10 mg/kg CP on day 10. CP treatment caused the damage on some spermatological parameters (motility, live sperm rate, and abnormal sperm rate), increased the oxidative stress, and induced testicular degeneration and apoptosis. However, CARV treatment mitigates CP‐induced reproductive toxicity. 相似文献
49.
Damar Sibel Bozogğlu Faruk Hızal Mirzahan Bayındırlı Alev 《World journal of microbiology & biotechnology》2002,18(1):1-6
Two pathogenic microorganisms Escherichia coli O157:H7 and Staphylococcus aureus, suspended in peptone solution (0.1% w/v) were treated with 12, 14, 16 and 20 kV/cm electric field strengths with different pulse numbers up to 60 pulses. Pulsed electric field (PEF) treatment at 20 kV/cm with 60 pulses provided nearly 2 log reduction in viable cell counts of E. coli O157:H7 and S. aureus. S. aureus cells were slightly more resistant than E.coli O157:H7 cells. The results related to the effect of initial cell concentration of E. coli O157:H7 on the PEF inactivation showed that more inactivation was obtained by decreasing initial cell concentration. Any possible injury by PEF was also investigated after applying 20 kV/cm electric field to the microorganisms. As a result, it was determined that there was 35.92 to 43.36% injury in E. coli O157:H7 cells, and 17.26 to 30.86% injury in S. aureus cells depending on pulse number. The inactivation results were also described by a kinetic model. 相似文献
50.
Ekinci D Beydemir S Küfrevioğlu OI 《Journal of enzyme inhibition and medicinal chemistry》2007,22(6):745-750
The inhibition of two human carbonic anhydrase (HCA, EC 4.2.1.1) isozymes, the cytosolic HCA I and II, with heavy metal salts of Pb(II), Co(II) and Hg(II) has been investigated. Human erythrocyte CA-I isozyme was purified with a specific activity of 920 EUmg(-1) and a yield of 30% and CA-II isozyme was purified with a specific activity of 8000 EUmg(-1) and a yield of 40% using Sepharose-4B-L tyrosine-sulfanilamide affinity gel chromatography. The overall purification was approximately 104-fold for HCA-I and 900-fold for HCA-II. The inhibitory effects of different heavy metals (lead, cobalt and mercury) on CA activity were determined at low concentrations using the esterase method under in vitro conditions. Ki values for these metals were calculated from Lineweaver-Burk graphs as 1.0, 3.22 and 1.45 mM for HCA-I and 0.059, 1.382 and 0.32 mM for HCA-II respectively. Lead was a noncompetitive inhibitor for HCA-I and competitive for HCA-II, cobalt was competitive for HCA-I and noncompetitive for HCA-II and mercury was uncompetitive for both HCA-I and HCA-II. Lead was the best inhibitor for both HCA-I and HCA-II. 相似文献