全文获取类型
收费全文 | 9320篇 |
免费 | 529篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 223篇 |
妇产科学 | 179篇 |
基础医学 | 1333篇 |
口腔科学 | 1049篇 |
临床医学 | 595篇 |
内科学 | 1834篇 |
皮肤病学 | 217篇 |
神经病学 | 558篇 |
特种医学 | 338篇 |
外科学 | 968篇 |
综合类 | 65篇 |
一般理论 | 3篇 |
预防医学 | 964篇 |
眼科学 | 284篇 |
药学 | 667篇 |
中国医学 | 107篇 |
肿瘤学 | 388篇 |
出版年
2023年 | 84篇 |
2022年 | 198篇 |
2021年 | 360篇 |
2020年 | 217篇 |
2019年 | 309篇 |
2018年 | 372篇 |
2017年 | 231篇 |
2016年 | 281篇 |
2015年 | 350篇 |
2014年 | 430篇 |
2013年 | 493篇 |
2012年 | 772篇 |
2011年 | 781篇 |
2010年 | 408篇 |
2009年 | 355篇 |
2008年 | 540篇 |
2007年 | 542篇 |
2006年 | 447篇 |
2005年 | 378篇 |
2004年 | 416篇 |
2003年 | 289篇 |
2002年 | 228篇 |
2001年 | 170篇 |
2000年 | 135篇 |
1999年 | 127篇 |
1998年 | 78篇 |
1997年 | 66篇 |
1996年 | 43篇 |
1995年 | 43篇 |
1994年 | 28篇 |
1993年 | 17篇 |
1992年 | 45篇 |
1991年 | 45篇 |
1990年 | 53篇 |
1989年 | 55篇 |
1988年 | 56篇 |
1987年 | 65篇 |
1986年 | 47篇 |
1985年 | 44篇 |
1984年 | 22篇 |
1983年 | 33篇 |
1982年 | 16篇 |
1981年 | 19篇 |
1980年 | 24篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1976年 | 20篇 |
1975年 | 17篇 |
1974年 | 15篇 |
1973年 | 17篇 |
排序方式: 共有9889条查询结果,搜索用时 15 毫秒
91.
Damasceno NR Goto H Rodrigues FM Dias CT Okawabata FS Abdalla DS Gidlund M 《The Journal of nutrition》2000,130(11):2641-2647
The incidence of atherosclerosis can be modified by diet, and plant-derived proteins have a beneficial effect, but the underlying mechanisms remain unclear. It has been suggested that oxidized LDL (oxLDL) and autoantibodies against oxLDL are important in the development of atherosclerosis. We analyzed these factors in rabbits fed a nonpurified diet supplemented with high cholesterol (10.0 g/kg) containing either 270.0 g/kg casein (CAS, n = 10) or 270.0 g/kg soy protein isolate (SPI, n = 10) for 2 mo. Plasma and purified serum LDL from rabbits were analyzed at d 0, 15, 30, 45 and 60 of treatment, and the size of atherosclerotic lesions was evaluated at d 60 of treatment. CAS-fed rabbits had significantly higher plasma cholesterol at d 15-45 and LDL cholesterol levels at d 15 and 30. Levels of trilinolein and phosphatidylcholine hydroperoxides were higher in the LDL fraction of rabbits fed CAS than in those fed SPI. Also, CAS-fed rabbits had higher levels of highly oxidized LDL [monoclonal antibody (mAb) 24-reactive oxLDL] in plasma at d 60, whereas SPI-fed rabbits had higher levels of minimally oxidized LDL (mAb 28-reactive oxLDL) at d 45. These results were consistent with the earlier formation of anti-oxLDL antibodies and the presence of a larger area of atherosclerotic lesion in rabbits fed the CAS diet. These data indicate the importance of both the type of dietary protein used in the induction of atherosclerosis and the relevance of immunologic mechanisms in addition to biochemical and physiologic factors in the pathogenesis of atherosclerosis. 相似文献
92.
Christopher R Gibson Charles Lin Rominder Singh Cheri M Brown Karen Richards Janice Brunner Kimberly Michel Jennifer Adelsberger Edward Carlini Catherine Boothe-Genthe Conrad Raab Minh Luu Aimee Michael Mona Parikh Patrice Ciecko Raju Subramanian Paul Krolikowski A David Rodrigues Thomas A Baillie Thomas H Rushmore 《Drug metabolism and disposition》2005,33(7):1044-1051
Compound I [3-[5-(4-methanesulfonyl-piperazin-1-ylmethyl)-1H-indol-2-yl]-1H-quinolin-2-one] is a potent inhibitor of human kinase insert domain-containing receptor (KDR kinase), which is under investigation for the treatment of cancer. Bile duct-cannulated male beagle dogs were administered 6 mg/kg compound I q.d. for 14 days. There was an approximately 2.5-fold decrease in the mean plasma area under the curve of I on days 7 and 14 (approximately 11.3 microM . h), relative to day 1 (28.2 microM . h). In the dog, compound I was eliminated by metabolism, with a major pathway being aromatic hydroxylation and subsequent sulfation to form the metabolite M3. Metabolic profiling suggested that the pathway leading to the formation of the sulfated conjugate M3 was induced upon multiple dosing of I. Studies conducted in vitro suggested that CYP1A1/2 was responsible for the formation of the hydroxylated metabolite, which is sulfated to yield M3. Additional studies confirmed induction of CYP1A protein and activity in the livers of dogs treated with I. However, studies in a dog hepatocyte model of induction showed a surprising decrease both in CYP1A mRNA and enzymatic activity in the presence of I, emphasizing the need to consider the results from a variety of in vitro and in vivo studies in deriving an understanding of the metabolic fate of a drug candidate. It is concluded that the autoinduction observed after multiple treatments with compound I occurs since compound I is both an inducer and a substrate for dog CYP1A. 相似文献
93.
Elisabeth Meloni Vieira Alcyone Artioli Machado Geraldo Duarte Regina Helena Brito de Souza Antonio Luis Rodrigues Junior 《Pan American journal of public health》2004,15(6):373-379
OBJECTIVES: To study HIV-positive women and women at risk of becoming infected with HIV who attended HIV prevention education group sessions at a university hospital in Brazil and to compare the use of the female condom and the male condom by these two groups of women. METHODS: The study subjects were 165 women participating in HIV prevention education group sessions at the Medical School Hospital of Ribeir?o Preto of the University of S?o Paulo, in the city of Ribeir?o Preto, S?o Paulo, Brazil. Women could be enrolled in the study from August 2000 to June 2001, and the follow-up observation time period was from August 2000 to July 2001. Male condoms and female condoms were freely distributed to all the participants at the end of each educational session and also at the end of each follow-up visit that the participants made. Each woman took part in an initial interview and was asked to return monthly. At each follow-up visit an additional short interview was carried out in order to investigate use of the male condom and of the female condom. Variables that were examined for the study included age, education, ethnic group, marital or relationship status, number of children, the women's use of male condoms and female condoms, commercial sex (whether the women had ever had sex in exchange for money, gifts, or favors), and previous knowledge of the female condom. RESULTS: The 165 women studied fell into the following three categories: 132 of them (80.0%) were HIV-positive, 26 of them (15.8%) had a sexually transmitted disease (STD) other than HIV and did not have an HIV-positive partner, and 7 of them (4.2%) had an HIV-positive partner but did not have HIV or any other STD. The women ranged in age from 15 to 64 years, with a mean of 30.3 years. Of the women in the study, 69.7% of them were married or were cohabitating, and 90.9% of them had a sexual partner. Just over two-thirds of the women had seven years of formal schooling or less. Out of 163 women, a total of 31 of them (19.0%) had never used the male condom with a partner, and 49 of the 163 (30.1%) had not used a male condom at the time of the last sexual intercourse. Out of the 165 women, 74 of them (44.8%) returned for at least one follow-up visit. Of these 74 women, 58 of them (78.3%) reported using the female condom between the initial interview and the first follow-up visit. The majority of the 74 women who returned for a visit liked using the female condom, and the women reported that their partners also generally accepted the female condom. In comparison to women at risk of HIV, HIV-positive women were more likely to have used the male condom with a partner before the initial interview. Women who continued returning over a longer follow-up period were more likely to have used the female condom at the time of the last sexual intercourse. No association was found between female condom use at the time of last sexual intercourse and the woman's HIV infection status. CONCLUSIONS: In comparison to the women at risk of HIV, the HIV-positive women in our study were more likely to use male condoms with their partners, to return for follow-up visits, and to have a longer follow-up period. The acceptance of the female condom among the HIV-positive women in this study, as reported at their first follow-up visit, appears to be similar to the acceptance of the female condom among women in general in Brazil. 相似文献
94.
Amaury Léis Dal Fabbro 《生殖与避孕(英文版)》2006,17(2):89-96
Objective To know the characteristics of contraceptive use in Sao Paulo State collected by the Demographic and Health Survey (DHS) conducted in 1996.
Methods Data of Sao Paulo in 1996 were analyzed compared with the previous DHS carried on in 1986focusing on Sao Paulo State. Contraceptive use among married or cohabiting women by age, number of children and schooling was closely examined. Age and timing of female sterilization were also analyzed.
Results The results showed that unlike Brazil there was a stability of female sterilization in Sao Paulo State during 1986 and 1996. There was a pattern in Sao Paulo: up to 30 years old the pill was the most used contraceptive, after 30 there was a predominance of female sterilization, which increased with the number of children and decreased with schooling. The use of male methods had also increased in the 1986 and 1996 period, being greater in Sao Paulo than in Brazil. Sao Paulo also presented more diversity in the use of reversible contraceptives.
Conclusions The predominant two contraceptive methods in Brazil and Sao Paulo changed from 1986 to 1996, i.e..from pill to female sterilization. 相似文献
95.
Latimer VS Rodrigues SM Garyfallou VT Kohama SG White RB Fernald RD Urbanski HF 《Brain research. Molecular brain research》2000,75(2):287-292
Gonadotropin-releasing hormone represents the primary neuroendocrine link between the brain and the reproductive axis, and at least two distinct molecular forms of this decapeptide (GnRH-I and GnRH-II) are known to be expressed in the forebrain of rhesus macaques (Macaca mulatta). Although the distribution pattern of the two corresponding mRNAs is largely dissimilar, their expression appears to show some overlap in specific regions of the hypothalamus; this raises the possibility that some cells express both molecular forms of GnRH. To resolve this issue, double-label histochemistry was performed on hypothalamic sections from six male rhesus macaques, using a monoclonal antibody to GnRH-I and a riboprobe to monkey GnRH-II mRNA. In total, more than 2000 GnRH neurons were examined but in no instance were GnRH-I peptide and GnRH-II mRNA found to be coexpressed. This finding emphasizes that GnRH-I and GnRH-II are synthesized by two distinct populations of hypothalamic neurons, and suggests that they may be regulated by different neuroendocrine pathways. 相似文献
96.
Evidence for dual effects of nitric oxide in the forced swimming test and in the tail suspension test in mice 总被引:1,自引:0,他引:1
L-Arginine (L-Arg), a substrate for nitric oxide synthase (NOS) at a dose of 250-500 mg/kg, i.p., significantly reduced the duration of immobility both in the forced swimming test (FST) and in the tail suspension test (TST), two models of depression in mice, without changing locomotion in an open field. Paradoxically, a similar effect was observed with the administration of N(G)-nitro-L-arginine (L-NNA) (0.3-10 mg/kg, i.p.), an inhibitor of NOS. However, higher doses of L-Arg (750-1000 mg/kg) and L-NNA (30 mg/kg) did not produce any anti-immobility effect in FST and TST. The inactive isomers D-Arg (100-1000 mg/kg, i.p.) and D-NNA (0.3-30 mg/kg, i.p.) did not affect immobility duration in either the FST and TST. Preadministration of L-NNA (30 mg/kg, i.p.), but not of D-NNA completely blocked the anti-immobility effect of L-Arg (500 mg/kg, i.p.) in the FST. Similarly, L-Arg (750 mg/kg, i.p.), but not D-Arg blocked the anti-immobility effect of L-NNA (3 mg/kg, i.p.) in the FST. The results indicate that either the synthesis of NO or the inhibition of its synthesis may produce antidepressant-like effects when assessed in the FST and TST. The physiological meaning of this finding is still obscure, but it could indicate that NO has a dual role in the modulation of depression. 相似文献
97.
A Fogliata G Nicolini M Alber M Asell B Dobler M El-Haddad B H?rdemark U Jelen A Kania M Larsson F Lohr T Munger E Negri C Rodrigues L Cozzi 《Radiotherapy and oncology》2005,76(3):300-310
BACKGROUND AND PURPOSE: To evaluate the performance of ten different treatment-planning systems when intensity modulated (IMRT) plans are designed for breast treatments that include the irradiation of the internal mammary chain. PATIENTS AND METHODS: A dataset of five patients (CT images and volumes of interest) was distributed to design IMRT plans on the ten systems. To minimise biases, the same geometry and clinical planning aims were imposed on the individual plans. Results were analysed in terms of dose distributions and dose volume histograms. RESULTS AND CONCLUSIONS: For target coverage, the volume receiving more than 95% of the prescribed dose ranged from 77% (OTP) to 91% (Eclipse and Pinnacle), the volume receiving more than 107% ranged from 3.3% (Hyperion) to 23.2% (OTP). The mean dose to ipsilateral lung ranged from 13 Gy (Eclipse) to 18 Gy (OTP). The volume of the contralateral breast receiving more than 10 Gy ranged from 3% (Pinnacle) to 26% (Precise). The volume of heart receiving more than 20 Gy ranged from 7% (Eclipse) to 47% (Precise), the maximum significant dose to heart ranged from approximately 27 Gy (XiO) to approximately 49 Gy (Precise). The maximum significant dose to healthy tissue ranged from approximately 51 Gy (Eclipse) to approximately 62 Gy (OTP). It was also possible to show that the treatment geometry proposed here enables to minimise contralateral breast irradiation while keeping minimal ipsilateral lung (or heart) involvement and satisfactory target coverage. 相似文献
98.
Anti-inflammatory effects of fructose-1,6-bisphosphate on carrageenan-induced pleurisy in rat. 总被引:3,自引:0,他引:3
José Carlos Farias Alves Filho Roberto Christ Vianna Santos Telmo Abelin Castaman Jarbas Rodrigues de Oliveira 《Pharmacological research》2004,49(3):245-248
In the present study, we evaluated the effect of fructose-1,6-bisphosphate (FBP), a high energy intermediate metabolite of glycolysis, in an acute model of lung injury. Injection of carrageenan into the pleural cavity of rats elicited an acute inflammation response characterized by a fluid accumulation in the pleural cavity which contained a large number of polymorphonuclear neutrophils. FBP (500mg/kg) attenuated the inflammation parameters: exudate volume, total leukocytes and the number of polymorphonuclear leukocytes, but the protein concentration in the exudate was not significantly affected by treatment with FBP. The precise site and mechanism of the anti-inflammatory effect was not addressed, considering the diverse pharmacological actions of FBP. This drug has anti-inflammatory actions suggesting that it may represent a novel strategy for the modulation of inflammatory response. 相似文献
99.
Veridiana M Rodrigues Silvana Marcussi Rafael S Cambraia Ana L de Araújo Natael R Malta-Neto Amélia Hamaguchi Eloísa A V Ferro Maria I Homsi-Brandeburgo José R Giglio Andreimar M Soares 《Toxicon》2004,44(3):305-314
Two basic myotoxic PLA(2)s, namely BnpTX-I and II, were isolated from Bothrops neuwiedi pauloensis snake venom through three chromatographic steps: ion-exchange chromatography on CM-Sepharose, gel filtration on Sephadex G-50 and reverse phase HPLC on a C18 column. Both PLA(2)s showed a M(r) around 14,000 for the monomer and 28,000 for the dimer (as estimated by SDS-PAGE), pI approximately 7.8 and approximately 121 amino acid residues cross-linked by seven disulfide bonds. The N-terminal sequences revealed significant homology with Asp49 basic myotoxic PLA(2)s from other snake venoms. The catalytic and anticoagulant activities of BnpTX-I were higher than those of BnpTX-II. Both were able to induce cytotoxicity in vitro, as well as, myotoxicity, edema and lethality in mice. BnpTX-I also induced neurotoxic effect on mouse neuromuscular preparations and bactericidal activity on Eschericia coli and Staphylococcus aureus. After chemical modification of BnpTX-I with BPB or incubation with EDTA or Mn(2+) ions, the catalytic activity was completely abolished, while the toxic and pharmacological activities were partially reduced. Interaction with heparin inhibited the cytotoxic and bactericidal effects. Anti-BthTX-I, anti-BthTX-II and anti-115-129-C terminal antibodies strongly recognize both BnpTX-I and II. It is shown that the neurotoxic effect induced by B. neuwiedi pauloensis venom is due to the presence of myotoxic PLA(2)s. The data also corroborate the hypothesis of a partial dissociation between toxic and enzymatic domains. In addition, BnpTX-I displays a heparin binding C-terminal region, which is probably responsible for the cytotoxic and bactericidal effects. 相似文献
100.