全文获取类型
收费全文 | 4805篇 |
免费 | 299篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 178篇 |
妇产科学 | 85篇 |
基础医学 | 618篇 |
口腔科学 | 87篇 |
临床医学 | 842篇 |
内科学 | 938篇 |
皮肤病学 | 27篇 |
神经病学 | 356篇 |
特种医学 | 194篇 |
外科学 | 473篇 |
综合类 | 35篇 |
一般理论 | 3篇 |
预防医学 | 532篇 |
眼科学 | 48篇 |
药学 | 302篇 |
中国医学 | 4篇 |
肿瘤学 | 362篇 |
出版年
2022年 | 41篇 |
2021年 | 83篇 |
2020年 | 62篇 |
2019年 | 94篇 |
2018年 | 101篇 |
2017年 | 62篇 |
2016年 | 84篇 |
2015年 | 88篇 |
2014年 | 131篇 |
2013年 | 230篇 |
2012年 | 282篇 |
2011年 | 298篇 |
2010年 | 176篇 |
2009年 | 117篇 |
2008年 | 248篇 |
2007年 | 257篇 |
2006年 | 246篇 |
2005年 | 300篇 |
2004年 | 277篇 |
2003年 | 285篇 |
2002年 | 274篇 |
2001年 | 57篇 |
2000年 | 68篇 |
1999年 | 73篇 |
1998年 | 52篇 |
1997年 | 58篇 |
1996年 | 33篇 |
1995年 | 49篇 |
1994年 | 31篇 |
1993年 | 27篇 |
1992年 | 61篇 |
1991年 | 50篇 |
1990年 | 52篇 |
1989年 | 39篇 |
1988年 | 45篇 |
1987年 | 37篇 |
1986年 | 43篇 |
1985年 | 40篇 |
1984年 | 36篇 |
1983年 | 42篇 |
1982年 | 32篇 |
1981年 | 47篇 |
1980年 | 25篇 |
1979年 | 24篇 |
1978年 | 30篇 |
1977年 | 29篇 |
1976年 | 22篇 |
1975年 | 23篇 |
1974年 | 23篇 |
1967年 | 21篇 |
排序方式: 共有5119条查询结果,搜索用时 15 毫秒
71.
Kameyama K Maeda M Okamoto T Sugita A Hayashi E Nakamoto K 《Kyobu geka. The Japanese journal of thoracic surgery》1999,52(13):1078-1083
Placement of stents for the tracheal or carinal stenosis have a meaning of maintaining the airway. Failure of the stenting causes death. In cases of severe airway stenosis and low pulmonary function, the pulmonary support method should be performed instead of intubation and mechanical ventilation. Generally, PCPS (percutaneous cardio-pulmonary support system) is used as a pulmonary support. This method was very useful to place stents for airway stenosis. We concluded that PCPS was useful in emergency cases, and in cases of severe fixed type airway stenosis and low pulmonary function it had be on stand-by. 相似文献
72.
Interethnic difference in drug disposition is an important contributing factor to interindividual variation in drug response. Since interethnic differences in the protein binding of drugs may contribute to variation in drug disposition between ethnic groups, we conducted a study in 10 black Americans (A) and mean (plus minusSE) age 26 plus minus 6 years and weight 80 plus minus 9 kg matched against 10 white Americans (C) with a mean age of 28 plus minus 6 years and weight 81 plus minus 9 kg, all within 10% of ideal body weight. Serum alpha-1-acid glycoprotein (AGP) and albumin concentrations were measured using the auramine-O and bromcresol green methods, respectively. Verapamil, propranolol, lidocaine, disopyramide and diazepam binding in plasma were measured with the equilibrium-dialysis method, involving the determination of free and unbound drug concentrations. The unbound fraction of diazepam (A = 1.1 plus minus 0.1%; C = 1.1 plus minus 0.1%), verapamil (A = 9.5 plus minus 0.8%; C = 9.8 plus minus 0.4%), propranolol (A = 14.2 plus minus 1.0%; C = 12.6 plus minus 0.7%), lidocaine (A = 28.5 plus minus 2.1%; C = 25.7 plus minus 1.1%) and diphenhydramine (A = 42.9 plus minus 10.2; C = 30.4 plus minus 7.01%) showed no significant ethnic differences (unpaired t-test). Disopyramide measured at 7 different concentrations (1.0--20.0 &mgr;g/ml) was similar in both groups, as were the plasma concentrations of AGP (A = 100 plus minus 20 mg 100 ml; C = 120 plus minus 20 mg 100 ml) and albumin (A = 4.3 plus minus 0.1 g 100 ml; C = 4.5 plus minus 0.1 g 100 ml). It is therefore concluded that there are no interethnic differences in the protein binding of basic drugs between black Americans and white Americans and that it is not a major contributing factor to any possible interethnic variation in the disposition of responsiveness of these drugs. 相似文献
73.
Clinical backgrounds in two kinds (absolute and relative) of mild pregnancy induced hypertension] 总被引:3,自引:0,他引:3
S Tomoda A Hidaka T Kitanaka O Nakamoto T Sugawa 《Nippon Sanka Fujinka Gakkai zasshi》1991,43(12):1674-1680
The criteria for pregnancy induced hypertension (PIH) have been determined by the Japanese Obstetrics and Gynecology Society. Mild PIH is classified into two types. One is "Absolute-PIH (A-PIH)" diagnosed by 1) systolic blood pressure (SBP) greater than = 140mmHg and less than 160mmHg or 2) diastolic blood pressure (DBP) greater than = 90mmHg and less than 110mmg. Another one is "Relative-PIH (R-PIH)" diagnosed by 3) an increase in SBP greater than = 30mmHg compared to normal SBP or 4) an increase in DBP greater than = 15mmHg compared to normal DBP. However, there has been no report in which two types of PIH are assessed. Our hypothesis is that the pathophysiology of two types of PIH is different. The purpose of this study is to clarify the pathophysiological difference by evaluating the clinical backgrounds. We evaluated 963 nullipara and 747 multipara whose pregnancies were recorded from the 1st trimester (multiple pregnancy and pre-term delivery before 32 gestational weeks were excluded). Among 765 nullipara women, 79.4% were diagnosed as having normal blood pressure (N-group), 7.1% as A-PIH, and 13.0% as R-PIH. In the multipara N-group, the figures were 632 women (84.6%), A-PIH, 4.6% and R-PIH, 10.3%. Clinical backgrounds showed that the incidence of hypertensive family history, high hematocrit (greater than = 39.0) before the 12th gestational week or obesity (Kaup index greater than = 24 before pregnancy) was significantly higher in A-PIH than in the N-group of nullipara and higher in the A-PIH than in the R-PIH and N-groups of multipara.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
74.
Covalent binding of isomeric benzo[a]pyrene diol-epoxides to DNA 总被引:1,自引:0,他引:1
We have compared the abilities of two diol-epoxide derivativesof benzo[a]pyrene (B[a]P) to bind covalently to DNA in a simplein vitro system. Purified DNA in aqueous solution was allowedto react with (±)-7, 8ß-dihydroxy-9ß,10ß-oxy-7,8,9,10-tetrahydroB[a]P (BPDE) or with (±)-9,10ß-dihydroxy-7,8-oxy-7,8,9,10-tetrahydroB[a]P (reverseBPDE) to completion. After repurification of the DNA, bindingwas detected by fluorescence spectroscopy or by absorbance spectroscopy.Both BPDE and reverse BPDE but not their hydrolysis productsexhibited binding which increased linearly with increasing diolepoxide concentration. When DNA modified by reverse BPDE wasenzymatically hydrolysed, two major fluorescent deoxyribonucleoside-adductswere detected by reverse phase h.p.l.c. These were separablefrom the major adduct obtained from BPDE-modified DNA and fromthe major products obtained by hydrolysis of reverse BPDE inthe absence of DNA. Absorbance and fluorescence spectroscopyof modified native DNA suggested that the pyrene nucleus ofreverse BPDE but not of BPDE was intercalated in the DNA doublehelix. This suggestion was supported by fluorescence-quenchingstudies. In the presence of increasing DNA concentrations, covalentbinding of both diol epoxides increased towards an apparentmaximum. Double reciprocal analysis of the data indicated amaximum binding level of 5% of the total dose for BPDE and 4%for reverse BPDE. This suggests that for both diol epoxidesthe ratio of the rate constants for covalent binding and forDNA-enhanced hydrolysis are nearly the same. Covalent bindingof reverse BPDE to DNA was effectively blocked by low concentrationsof Mg2+, suggesting that formation of a non-covalent intercalationcomplex may be a prerequisite for covalent reaction. 相似文献
75.
76.
Polilactofate microspheres for Paclitaxel delivery to central nervous system malignancies. 总被引:1,自引:0,他引:1
Khan W Li Wenbin Dang Betty M Tyler Greg Troiano Tarik Tihan Henry Brem Kevin A Walter 《Clinical cancer research》2003,9(9):3441-3447
PURPOSE: The purpose of this study was to demonstrate that surgically implanted, controlled-release, biodegradable polilactofate microspheres (Paclimer) can be used safely to bypass the blood-brain barrier and deliver paclitaxel to malignant brain tumors. EXPERIMENTAL DESIGN: The rate of paclitaxel release from Paclimer microspheres submerged in PBS was measured in vitro by high-performance liquid chromatography. In vivo studies of Paclimer were performed as intracranial implants in Fischer 344 rats in the presence or absence of 9L gliosarcoma. Mantel-Cox statistics were used to assess the efficacy of Paclimer at extending survival of tumor-bearing animals compared with control implants. Paclimer implants tagged with [(3)H]paclitaxel were used to measure biodistribution of paclitaxel from the Paclimer implant. RESULTS: Paclimer released paclitaxel at a constant rate for up to 3 months in vitro. In vivo, Paclimer implants placed intracranially in rats released active drug for up to 30 days after implantation and doubled the median survival of rats bearing established 9L gliosarcomas (median survival of paclitaxel-treated animals = 35 days; median survival of control-treated animal = 16 days; P < 0.0001). Active drug was distributed throughout the rat brain based on liquid scintillation counting and TLC. Rats implanted with Paclimer demonstrated no overt signs of neurotoxicity and exhibited local cytopathological changes consistent with exposure to an antimicrotubule agent. CONCLUSIONS: Paclimer extends survival in a rodent model of glioma with minimal morbidity and optimal pharmacokinetics. 相似文献
77.
78.
Mehrdad Asadifar Malectaj Yazdani Ramin Sadeghpour Chris Bruno Jeffrey Green Andrew T Nakamoto Pegah Hosseini Farahnaz Fahami Sheila Gottschalk Tetsuo Nakamoto 《Food and chemical toxicology》2005,43(3):451-456
We hypothesized that the pathological effects on the neonatal rat heart could be aggravated by Cu deficiency due to the combined effects of caffeine exposure and malnutrition. Upon birth, pups were mixed and randomly picked; 8 pups were assigned to each dam and then divided into 4 groups. Group 1 dams received a normal diet containing 20% protein. Group 2 dams were fed 20% protein diet supplemented with caffeine (4 mg/100 g BW). Group 3 dams received 6% protein diet as a malnourished group, and group 4 dams received 6% protein diet supplemented with caffeine (4 mg/100 g BW). On postnatal day 10, dams and pups were killed. Group 2 tended to have a decrease in the Cu levels of dams' plasma and milk and in pups' plasma and heart tissue compared to those of group 1. This pattern was not observed consistently between groups 3 and 4. Transmission electron microscopy of group 2 pups' hearts revealed a degree of disruption in the mitochondria compared to normal mitochondria seen in group 1. There was no consistent change in the mitochondria of group 4 compared to group 3. The caffeine level observed in all categories of group 4 (dams' plasma and milk, pups' plasma and heart tissue) was lower than those in group 2. Although malnutrition affected body weight and heart weight, combined effects of caffeine and malnutrition on Cu content in the neonatal heart was relatively minor compared to the well nourished group. This well nourished group showed that the effects of caffeine on Cu were more consistent, resulting the changes of mitochondria. 相似文献
79.
Xin Fu John R Latendresse Levan Muskhelishvili Betty S Blaydes K Barry Delclos 《Food and chemical toxicology》2005,43(5):765-774
In this study, dietary modulation of 7,12-dimethylbenz[a]anthracene (DMBA)-induced adrenal toxicity in rats was investigated. Beginning at postnatal day (PND) 21, female Sprague-Dawley rats were fed either soy-containing NIH-31 diet or soy- and alfalfa-free 5K96 diet. On the first day of diestrus when the animals were PND 50 +/- 5, rats received either an oral dose of 80 mg/kg DMBA or sesame oil, the vehicle, and were sacrificed at 24, 36, or 48 h after treatment. Apoptosis was manifested at 24 and 36 h after DMBA treatment in the zona reticularis (ZR) and the zona fasciculata (ZF) of the adrenal cortex; this was followed by severe hemorrhagic necrosis at 48 h. DMBA-induced apoptosis, evaluated by the TUNEL assay, immunohistochemical analysis of activated caspase 3, and the ratio of expression of pro-apoptotic Bax to anti-apoptotic Bcl2, was greater in rats fed NIH-31 diet relative to rats fed 5K96 diet at 24 h after treatment. Four of six DMBA-treated rats fed 5K96 diet had severe adrenal necrosis by 48 h, whereas this lesion was present in only two of six DMBA-treated rats fed NIH-31 diet. DMBA also caused a significant decrease of serum corticosterone relative to controls at 48 h in rats fed 5K96 diet. The present study indicated that diet modulates DMBA-induced adrenal toxicity in female rats, with increased apoptosis early and reduced necrosis later in rats fed a soy-containing diet. 相似文献
80.