全文获取类型
收费全文 | 180806篇 |
免费 | 1276篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 1329篇 |
儿科学 | 6762篇 |
妇产科学 | 3188篇 |
基础医学 | 17274篇 |
口腔科学 | 1893篇 |
临床医学 | 12746篇 |
内科学 | 32001篇 |
皮肤病学 | 766篇 |
神经病学 | 16860篇 |
特种医学 | 9012篇 |
外科学 | 29643篇 |
综合类 | 2333篇 |
预防医学 | 18525篇 |
眼科学 | 2863篇 |
药学 | 9717篇 |
中国医学 | 658篇 |
肿瘤学 | 16547篇 |
出版年
2023年 | 52篇 |
2022年 | 116篇 |
2021年 | 208篇 |
2020年 | 123篇 |
2019年 | 211篇 |
2018年 | 22093篇 |
2017年 | 17460篇 |
2016年 | 19640篇 |
2015年 | 1110篇 |
2014年 | 1072篇 |
2013年 | 1065篇 |
2012年 | 7399篇 |
2011年 | 21479篇 |
2010年 | 19087篇 |
2009年 | 11723篇 |
2008年 | 19841篇 |
2007年 | 22057篇 |
2006年 | 902篇 |
2005年 | 2467篇 |
2004年 | 3641篇 |
2003年 | 4552篇 |
2002年 | 2683篇 |
2001年 | 339篇 |
2000年 | 475篇 |
1999年 | 212篇 |
1998年 | 236篇 |
1997年 | 225篇 |
1996年 | 107篇 |
1995年 | 113篇 |
1994年 | 112篇 |
1993年 | 72篇 |
1992年 | 60篇 |
1991年 | 116篇 |
1990年 | 144篇 |
1989年 | 92篇 |
1988年 | 72篇 |
1987年 | 51篇 |
1986年 | 34篇 |
1985年 | 36篇 |
1984年 | 31篇 |
1983年 | 29篇 |
1982年 | 34篇 |
1980年 | 53篇 |
1974年 | 23篇 |
1970年 | 23篇 |
1938年 | 60篇 |
1937年 | 25篇 |
1934年 | 30篇 |
1932年 | 56篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
871.
P S F Barbosa A M C Martins A Havt Daniela O Toyama J S A M Evangelista D P P Ferreira P P Joazeiro Luis O S Beriam Marcos H Toyama M C Fonteles H S A Monteiro 《Toxicon》2005,46(4):376-386
Bothrops jararacussu myotoxin I (BthTx-I; Lys 49) and II (BthTX-II; Asp 49) were purified by ion-exchange chromatography and reverse phase HPLC. In this work we used the isolated perfused rat kidney method to evaluate the renal effects of B. jararacussu myotoxins I (Lys49 PLA2) and II (Asp49 PLA2) and their possible blockage by indomethacin. BthTX-I (5 microg/ml) and BthTX-II (5 microg/ml) increased perfusion pressure (PP; ct120=110.28+/-3.70 mmHg; BthTX I=171.28+/-6.30*mmHg; BthTX II=175.50+/-7.20*mmHg), renal vascular resistance (RVR; ct120=5.49+/-0.54 mmHg/ml.g(-1)min(-1); BthTX I=8.62+/-0.37*mmHg/ml g(-1)min(-1); BthTX II=8.9+/-0.36*mmHg/ml g(-1)min(-1)), urinary flow (UF; ct(120)=0.14+/-0.01ml g(-1)min(-1); BthTX I=0.32+/-0.05*ml g(-1)min(-1); BthTX II=0.37+/-0.01*ml g(-1)min(-1)) and glomerular filtration rate (GFR; ct120=0.72+/-0.10 ml g(-1)min(-1); BthTX I=0.85+/-0.13*ml g(-1)min(-1); BthTX II=1.22+/-0.28*ml g(-1)min(-1)). In contrast decreased the percent of sodium tubular transport (%TNa(+); ct(120)=79,76+/-0.56; BthTX I=62.23+/-4.12*; BthTX II=70.96+/-2.93*) and percent of potassium tubular transport (%TK(+);ct120=66.80+/-3.69; BthTX I=55.76+/-5.57*; BthTX II=50.86+/-6.16*). Indomethacin antagonized the vascular, glomerular and tubular effects promoted by BthTX I and it's partially blocked the effects of BthTX II. In this work also evaluated the antibacterial effects of BthTx-I and BthTx-II against Xanthomonas axonopodis. pv. passiflorae (Gram-negative bacteria) and we observed that both PLA2 showed antibacterial activity. Also we observed that proteins Also we observed that proteins chemically modified with 4-bromophenacyl bromide (rho-BPB) decrease significantly the antibacterial effect of both PLA2. In conclusion, BthTx I and BthTX II caused renal alteration and presented activity antimicrobial. The indomethacin was able to antagonize totally the renal effects induced by BthTx I and partially the effects promoted by BthTx II, suggesting involvement of inflammatory mediators in the renal effects caused by myotoxins. In the other hand, other effects could be independently of the enzymatic activity of the BthTX II and the C-terminal domain could be involved in both effects promoted for PLA2. 相似文献
872.
Cháriston André Dal Belo Gildo Bernardo Leite Marcos Hikari Toyama Sergio Marangoni Alexandre Pinto Corrado Marcos Dias Fontana Andy Southan Edward G Rowan Stephen Hyslop Léa Rodrigues-Simioni 《Toxicon》2005,46(7):736-750
We have isolated a new phospholipase A2 (MiDCA1) from the venom of the coral snake Micrurus dumerilii carinicauda. This toxin, which had a molecular mass of 15,552Da, shared high sequence homology with the PLA2 toxins MICNI A and B from Micrurus nigrocinctus venom (77.7% and 73.1%, respectively). In chick biventer cervicis preparations, MiDCA1 produced concentration- and time-dependent neuromuscular blockade that reached 100% after 120 min (2.4 microM, n = 6); contractures to exogenously applied carbachol (8 microM) and KCl (13 mM) were still seen after complete blockade. In mouse phrenic-nerve diaphragm preparations, MiDCA1 (2.4 microM; n = 6) caused triphasic changes followed by partial neuromuscular blockade. Intracellular recordings of end-plate potentials (EPPs) and miniature end-plate potentials (MEPPs) from mouse diaphragm preparations showed that MiDCA1 increased the quantal content by 386+/-12% after 10 min (n = 14; p<0.05) and caused a triphasic change in the frequency of MEPPs. MiDCA1 also decreased the resting membrane potential, an effect that was prevented by tetrodotoxin and/or low extracellular calcium, but not by d-tubocurarine. The toxin increased the amplitude of mouse sciatic-nerve compound action potentials by 30+/-9% (0.6 microM; p<0.05). Potassium currents elicited in freshly dissociated dorsal root ganglia neurones were blocked by 31+/-1% (n = 4; p<0.05) in the presence of 2.4 microM MiDCA1. These results show that MiDCA1 is a new presynaptic phospholipase A2 that produces neuromuscular blockade in vertebrate nerve-muscle preparations. The triphasic effects seen in mammalian preparations and the facilitatory response were probably caused mainly by the activation of sodium channels, complemented by the blockade of nerve terminal potassium channels. The inability of d-turocurarine to prevent the depolarization by MiDCA1 indicated that cholinergic nicotinic receptors were not involved in this phenomenon. 相似文献
873.
Aida Baida Susan M Farrington Pere Galofré Ricard Marcos Antonia Velázquez 《Cancer epidemiology, biomarkers & prevention》2005,14(3):638-642
Although genetic and environmental factors have been identified in the etiology of thyroid cancer, the specific genetic implications in sporadic thyroid tumors are poorly understood but, as in other common cancers, low-penetrance susceptibility genes are believed to be crucial in the tumorigenesis processes. Here, we have carried out a case-control study to investigate whether there is an association between THRA1 CA repeat or BAT-40 A repeat polymorphisms and thyroid cancer risk. The THRA1 repeat resides in the thyroid hormone receptor-alpha1 gene, which is associated with thyroid cancer and whose expression depends on the THRA1 repeat size. We also analyzed the BAT-40 repeat that maps to chromosome 1, a region known to be involved in thyroid cancer. This repeat is located in the 3-beta-hydroxysteroid dehydrogenase gene that is associated with prostate cancer susceptibility. The THRA1 repeat was genotyped in 212 thyroid cancer patients and 141 controls of a Spanish population. From these individuals, 207 patients and 138 controls were also analyzed for the BAT-40 marker. No significant difference in the THRA1 allele distribution between patients and controls was found, although short alleles (<128 bp) might have some protective effect on thyroid cancer risk of carriers (odds ratio, 0.50; 95% confidence interval, 0.22-1.13; P = 0.094). By contrast, the BAT-40 allele distribution in patients was significantly different with respect to control (P = 0.035). Essentially, the difference were found in the genotypes involving the 111- to 115-bp allele range, which seem to be associated with a protective effect on thyroid cancer susceptibility in the studied population (odds ratio, 0.18; 95% confidence interval, 0.01-0.57; P = 0.02). Therefore, our results indicate that the BAT-40 containing region and to a less extend the thyroid hormone receptor-alpha1 gene are related to thyroid cancer susceptibility. To our knowledge, this is the first study reporting the identification of genetic factors for thyroid cancer susceptibility. 相似文献
874.
Brittany C. Thomas Stephen N. Thibodeau Noralane M. Lindor 《Current colorectal cancer reports》2005,1(2):103-109
Referrals to genetics services are becoming increasingly common for patients who are diagnosed with early-onset colorectal
cancer (CRC) or patients who have a family history of CRC. Microsatellite instability (MSI) testing and immunohistochemical
analysis (IHC) of the patient’s tumor tissue, which assess indirectly the cellular status of DNA mismatch repair, have proven
important tools for geneticists and genetic counselors to determine whether or not these individuals may be at risk for an
inherited cancer syndrome, Lynch syndrome (a subset of hereditary nonpolyposis colorectal cancer). The application of tumor
MSI/ IHC also extends to the group of providers involved in the diagnosis and management of CRC, demonstrating the growing
clinical applicability of MSI/IHC testing. This review discusses the clinical utility of MSI/IHC analysis, including its benefits
and limitations, and addresses some of the current debates surrounding testing. 相似文献
875.
The vast majority of new cases of colorectal cancer, the second most common cause of death in men and women in the United
States, are attributable to environmental rather than genetic causes. Recent research has clarified inconsistencies in the
literature and has explored new pathways through which risk factors may act. This review discusses newly published, selected
interesting and important findings in colorectal cancer etiology; these include postmenopausal hormone use, nonsteroidal anti-inflammatory
drug use, obesity, physical activity, diet, and other confirmed epidemiologic associations. This research provides insight
into mechanisms and offers opportunities for prevention. 相似文献
876.
Dolores Caballero Jose A García-Marco Rodrigo Martino Victoria Mateos José M Ribera José Sarrá Angel León Guillermo Sanz Javier de la Serna Rafael Cabrera Marcos González Jorge Sierra Jesús San Miguel 《Clinical cancer research》2005,11(21):7757-7763
PURPOSE: To evaluate the efficacy of reduced intensity conditioning (RIC) allogeneic transplant in 30 patients with poor-prognosis chronic lymphocytic leukemia (CLL) and/or high-risk molecular/cytogenetic characteristics. EXPERIMENTAL DESIGN: Eighty-three percent of patients had active disease at the moment of transplant. That is, 14 of the 23 patients analyzed (60%) had unmutated immunoglobulin variable heavy-chain gene (IgV(H)) status; 8 of 25 patients (32%) had 11q-, with four of them also displaying unmutated IgV(H); and six (24%) had 17p- (five were also unmutated). RESULTS: After a median follow-up of 47.3 months, all 22 patients alive are disease free; overall survival and event-free survival (EFS) at 6 years were 70% and 72%, respectively. According to molecular/cytogenetic characteristics, overall survival and EFS for unmutated CLL and/or with 11q- aberration (n = 13) were 90% and 92%, respectively, not significantly different to those with normal in situ hybridization, 13q- and +12, or mutated CLL (n = 7). All six patients with 17p deletion were transplanted with active disease, including three with refractory disease; all except one reached complete remission after the transplant and two are alive and disease free. Nonrelapse mortality (NRM) was 20%; more than two lines before transplant is an independent prognostic factor for NRM (P = 0,02), EFS (P = 0.02), and overall survival (P = 0.01). Patients older than 55 years have a higher risk of NRM (hazard ratio, 12.8; 95% confidence interval, 1.5-111). Minimal residual disease was monitored by multiparametric flow cytometry in 21 patients. Clearance of CD79/CD5/CD19/CD23 cells in bone marrow was achieved in 68% and 94% of the patients at days 100 and 360, respectively. CONCLUSION: According to these results, RIC allogeneic transplant could overcome the adverse prognosis of patients with unmutated CLL as well as those with 11q- or 17p-. 相似文献
877.
878.
879.
880.