全文获取类型
收费全文 | 2880篇 |
免费 | 167篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 158篇 |
妇产科学 | 222篇 |
基础医学 | 319篇 |
口腔科学 | 44篇 |
临床医学 | 192篇 |
内科学 | 524篇 |
皮肤病学 | 45篇 |
神经病学 | 101篇 |
特种医学 | 201篇 |
外科学 | 391篇 |
综合类 | 177篇 |
一般理论 | 1篇 |
预防医学 | 138篇 |
眼科学 | 77篇 |
药学 | 144篇 |
中国医学 | 42篇 |
肿瘤学 | 279篇 |
出版年
2023年 | 14篇 |
2022年 | 34篇 |
2021年 | 46篇 |
2020年 | 44篇 |
2019年 | 55篇 |
2018年 | 57篇 |
2017年 | 52篇 |
2016年 | 67篇 |
2015年 | 87篇 |
2014年 | 94篇 |
2013年 | 111篇 |
2012年 | 148篇 |
2011年 | 145篇 |
2010年 | 130篇 |
2009年 | 115篇 |
2008年 | 103篇 |
2007年 | 105篇 |
2006年 | 113篇 |
2005年 | 102篇 |
2004年 | 84篇 |
2003年 | 70篇 |
2002年 | 61篇 |
2001年 | 66篇 |
2000年 | 68篇 |
1999年 | 89篇 |
1998年 | 75篇 |
1997年 | 89篇 |
1996年 | 76篇 |
1995年 | 48篇 |
1994年 | 50篇 |
1993年 | 64篇 |
1992年 | 37篇 |
1991年 | 44篇 |
1990年 | 44篇 |
1989年 | 63篇 |
1988年 | 39篇 |
1987年 | 35篇 |
1986年 | 35篇 |
1985年 | 34篇 |
1984年 | 18篇 |
1982年 | 20篇 |
1981年 | 21篇 |
1980年 | 16篇 |
1979年 | 24篇 |
1977年 | 15篇 |
1976年 | 13篇 |
1974年 | 13篇 |
1973年 | 12篇 |
1972年 | 16篇 |
1966年 | 11篇 |
排序方式: 共有3074条查询结果,搜索用时 15 毫秒
991.
Résumé Le pancréas exocrine de la souris jeune obèsehyperglycémique de Bar Harbor et celui de la souris obèse Néo-Zélandaise adulte sont comparés à ceux de souris non-obèses témoins en dosant les activités potentielles de la lipase, de l'amylase, du chymotrypsinogène, du trypsinogène et de la ribonucléase dans la glande ainsi que les activités correspondant aux 4 premières protéines dans l'intestin grêle. Il résulte des dosages que ces paramètres du pancréas exocrine sont normaux dans les deux obésités congénitales considérées.
Abréviations utilisées DNA-P et RNA-P phosphore des acides désoxy- et ribonucléiques Boursier de l'O.C.D. (Belgique). 相似文献
Levels of pancreatic hydrolases in pancreas and small bowel of two types of obese mice with hyperinsulinism: The obese-hyperglycemic Bar-Harbor mouse (OH) and the New-Zealand mouse (NZO)
Summary The exocrine pancreas of young obese-hyperglycaemic mice from Bar Harbor and of adult New Zealand obese mice were compared with controls from non-obese animals. The potential activities of lipase, amylase, chymotrypsinogen, trypsinogen and ribonuclease were determined in the gland, as well as the activities corresponding to the first four proteins in the small intestine. These assays indicate that in the two congenital obesities considered, the exocrine function of the pancreas is characterized by normal enzymatic levels.
Die Spiegel der pankreatischen Hydrolasen in der Bauchspeicheldrüse und im Dünndarm bei 2 Arten von fetten Mäusen mit Hyperinsulinismus: der fettsüchtig-hyperglykämischen Bar-Harbor-Maus (OH) und der Neuseeland-Maus (NZO)
Zusammenfassung Die Funktion des exokrinen Pankreas wurde bei jungen fettsüchtig-hyperglykämischen Bar-Harbor-Mäusen und bei erwachsenen fettsüchtigen Neuseeland-Mäusen sowie bei nicht-fettsüchtigen Kontrolltieren verglichen. Die potentiellen Aktivitäten von Lipase, Amylase, Chymotrypsinogen, Trypsinogen und Ribonuclease wurden in der Drüse bestimmt, ferner die Aktivitäten der 4 erstgenannten Eiweißkörper im Dünndarm. Aus den Resultaten geht hervor, daß die Funktion des exokrinen Pankreas bei den beiden untersuchten Fettsuchtstypen durch normale Enzymaktivitäten charakterisiert ist.
Abréviations utilisées DNA-P et RNA-P phosphore des acides désoxy- et ribonucléiques Boursier de l'O.C.D. (Belgique). 相似文献
992.
Obermeier F Strauch UG Dunger N Grunwald N Rath HC Herfarth H Schölmerich J Falk W 《Gut》2005,54(10):1428-1436
BACKGROUND AND METHODS: Cytosin-guanosin dinucleotide (CpG) motifs of bacterial DNA are known to be potent activators of innate immunity. We have shown previously that administration of CpG containing oligodeoxynucleotide (CpG-ODN) to mice before the onset of dextran sodium sulphate induced colitis ameliorated colitis and inhibited induction of proinflammatory cytokines. To investigate the possible involvement of CD4(+) T cells in the prophylactic CpG-ODN effects, we used the SCID transfer model of colitis. RESULTS: CD4(+)CD62L(+) T cells from CpG-ODN treated donors did not induce significant intestinal inflammation in SCID recipients, in contrast with control cells. Additionally, cotransfer of these cells with CD4(+)CD62L(+) cells from normal mice protected recipient animals from colitis, indicating regulatory activity. Also, CD4(+)CD62L(+) cells from toll-like receptor 9 deficient animals induced a significantly more severe colitis in SCID recipients than cells from wild-type littermate controls, suggesting a similar protective role of "endogenous" bacterial DNA leading to a less "aggressive" phenotype of these cells. There was no detectable difference in regulatory T cell surface markers between aggressive and attenuated cell pools but attenuated cell pools showed reduced proliferation in vitro and in vivo and produced less interferon gamma, interleukin (IL)-5, and IL-6 after anti-CD3 stimulation. CONCLUSIONS: Collectively, our data support the concept that both endogenous bacterial DNA and exogenously supplied CpG motifs of bacterial DNA induce regulatory properties in CD4(+) T cells. Therefore, bacterial DNA derived from the normal gut flora may contribute essentially to the homeostasis between effector and regulatory immune mechanisms in healthy individuals to protect them from chronic intestinal inflammation. 相似文献
993.
T Stivland M Camilleri M Vassallo M Proano D Rath M Brown G Thomforde J Pemberton S Phillips 《Gastroenterology》1991,101(1):107-115
In this study, total gut transit and regional colonic transit in patients with idiopathic constipation were measured scintigraphically. Eight patients with severe constipation were studied, none of whom had evidence of abnormal function of the pelvic floor. 99mTc-radiolabeled Amberlite resin particles (average diameter, 1 mm; Sigma Chemical Co., St. Louis, MO) with a mixed meal were used to assess gastric emptying and small bowel transit; similar particles labeled with 111In were ingested in a coated capsule that dispersed in the ileocecal region. These were used to quantify colonic transit. Five healthy volunteers were also studied. Two patients showed delayed gastric emptying and two had slow small bowel transit. Seven of the eight patients had slow colonic transit. In five, delay affected the whole colon ("pancolonic inertia"); in two, transit in the ascending and transverse colon was normal, but solids moved through the left colon slowly. Mean colonic transit was also measured using radiopaque markers; this technique identified the patients with slow transit, as shown by measurements of overall colonic transit by simultaneous scintigraphy. However, estimated transit through the ascending and transverse colons was considerably shorter by the radiopaque marker technique. In conclusion, idiopathic constipation is characterized by either exaggerated reservoir functions of the ascending and transverse colons and/or impairment of propulsive function in the descending colon. Particle size may influence the result of regional colonic transit tests. Transit delays in other parts of the gut suggest that, in some patients, the condition may be a more generalized motor dysfunction. 相似文献
994.
BACKGROUND & AIMS: The molecular mechanisms underlying pancreatitis are largely unknown. The goal of this study was to identify an early genetic event that correlated with pancreatitis. METHODS: Differential display of messenger RNAs (mRNAs) was conducted on normal pancreas vs. those of animals with secretagogue-induced pancreatitis. Northern blots from normal animals and animals with experimental acute pancreatitis were probed with cloned complementary DNAs for chemokines. Pancreatitis was induced with cerulein and by retrograde injection of bile salts. Immunocytochemistry was used to identify the source of chemokine expression. Pyrrolidine dithiocarbamate was tested for effects on chemokine expression and pancreatitis. RESULTS: A differentially amplified band was consistently observed early after cerulein hyperstimulation. This band was identified as a portion of the mob-1 gene, an alpha-chemokine. Northern analysis indicated that mRNAs for mob-1 and another chemokine, mcp-1, were induced after cerulein hyperstimulation in vivo. mob-1 mRNA was also induced by retrograde injection of bile salts and by cerulein in acinar cells in vitro. mob-1 protein was localized to exocrine cells in pancreata of diseased animals. Pyrrolidine dithiocarbamate inhibited both chemokine gene expression and early inflammatory characteristics of pancreatitis. CONCLUSIONS: Chemokines are induced in acinar cells by treatments that induce pancreatitis and may play an important role in the early stages of the disease. (Gastroenterology 1997 Dec;113(6):1966-75) 相似文献
995.
Fidder HH Barshack I Chen-Shtoyerman R Onaca N Goldberg I Rath P Theodor L Bar-Meir S Friedman E 《Digestive diseases and sciences》2003,48(6):1102-1105
The I1307K APC germline mutation is associated with an increased risk to colorectal cancer (CRC). Whether and to what extent the somatic features and the molecular pathways of cancer development in mutation carriers differ from colorectal cancer in noncarriers remains unknown. To gain insight into this issue, 52 Israeli patients with CRC, 24 of whom were I1307K APC mutation carriers, were analyzed. The expression pattern of genes known to be involved in the pathogenesis of sporadic CRC was assessed immunohistochemically: E-cadherin, ß-catenin, deleted in colon cancer (DCC), and p53. In addition, tumors were genotyped for somatic activating mutations in Ki-rasoncogene. Mutation carriers and noncarriers were comparable in age at diagnosis (64.3 ± 10.1 years for carriers and 60.8 ± 14.1 years for noncarriers), tumor location in the colon, and disease stages. Tumors of I1307K mutation carriers displayed positive p53 immunostaining and loss of ß-catenin, E-cadherin, and DCC expression more often compared with noncarriers, although none of these differences reached statistical significance. Mutation frequencies in the Ki-ras gene were similar in both groups. In conclusion, the molecular pathways in CRC in I1307K APC mutation carriers are seemingly similar to those of sporadic cases, but a larger study is clearly needed. 相似文献
996.
Antitumor effect of a combination of lysine, proline, arginine, ascorbic acid, and green tea extract on pancreatic cancer cell line MIA PaCa-2 总被引:1,自引:0,他引:1
Roomi MW Ivanov V Kalinovsky T Niedzwiecki A Rath M 《Journal of gastrointestinal cancer》2005,35(2):97-102
Background: Current treatment of pancreatic cancer is generally associated with poor prognosis, even if diagnosed early, owing to its
aggressive rate of metastasis and non-responsiveness to chemotherapy and radiotherapy. Matrix metalloproteinases (MMPs) have
received much attention in recent years for their role in various malignancies, and have been implicated in tumor invasion,
metastasis, and angiogenesis.
Aim of Study: Reported antitum or properties of ascorbic acid, lysine, proline, and green tea extract prompted us to investigate the effect
of a combination of lysine, proline, arginine, ascorbic acid, and green tea extract on pancreatic cancer cell line MIA PaCa-2
for viability, MMP expression, invasion, and morphology.
Methods: Viability was evaluated based on cell proliferation by MTT assay and MMP expression in condition media by gelatinase zymography.
Invasion through Matrigel™ was assayed and morphology was observed by hematoxylin and eosin (H+E)staining. Data was analyzed
by independent sample “t” test.
Results: The nutrient mixture (NM) did not inhibit cell proliferation at 10 μg/mL and exhibited a dosedependent antiproliferative
effect with maximum inhibition of 38% over the control at demonstrated production of only MMP-9, which showed a dose-dependent
decreased expression that was abolished at 100 μg/mL of NM. Invasion through Matrigel was inhibited at 10, 50, 100, and 500
μg/mL by 66%, 66%, 87% and 100%, respectively. H&E staining did not indicate changes even at the highest concentration of
NM.
Conclusion: Our results suggest that the formulation of green tea extract, lysine, proline, and ascorbic acid, tested as a promising
adjunct to standard treatment of pancreatic cancer, by inhibiting MMP expression and invasion without toxic effects—important
parameters in cancer metastasis. 相似文献
997.
Lauer T Kleinbongard P Rath J Schulz R Kelm M Rassaf T 《Journal of internal medicine》2008,264(3):237-244
Background and objectives. Oxidized LDL cholesterol and cytokines increase arginase and decrease nitric oxide (NO) synthase expression in human endothelial cells, leading to a decrease in NO production. In arteriosclerotic plaques, characterized by increased oxidized LDL and cytokine levels, a sustained local NO reduction might enhance sensitivity of the downstream guanylyl cyclase system towards an acute NO increase. We tested whether application of the NO synthase substrate l ‐arginine (l ‐arg, 150 μmol min?1) or the NO donor isosorbide dinitrate (ISDN; 0.3 mg) preferentially dilates stenotic coronary artery segments (CS) subsequently increasing poststenotic coronary blood flow (CBF) in patients with coronary artery disease (CAD). Design, setting and subjects. Changes in coronary diameter and circumferential surface area were assessed by quantitative coronary angiography (QCA) in a nonstenotic upstream segment, the CS, downstream the CS and in a reference vessel (n = 24). CBF was estimated in a subset of 13 patients by QCA and intracoronary Doppler. Results. CS ranged from 62% to 89% (77 ± 5%). l ‐arg increased minimal luminal diameter of the stenotic segment from 0.98 ± 0.06 to 1.14 ± 0.07 mm (P < 0.05) without affecting other coronary segments. Poststenotic CBF increased by 24 ± 3%. ISDN dilated all segments again with a predominance of CS (25 ± 4%) and increased poststenotic CBF by 38 ± 9%. In a multifactorial anova , a medication with an angiotensin‐converting enzyme inhibitor (decreasing inflammation and radical formation) and a ratio of LDL/HDL <3.5 were predictive for an l ‐arg‐induced dilation. Conclusion. The increase in poststenotic CBF without affecting nondiseased arteries highlights the therapeutic potential of l ‐arg in patients with CAD. 相似文献
998.
Laura M. Palma Medina Eivind Rath Sanjeevan Jahagirdar Trond Bruun Martin B. Madsen Kristoffer Strlin Christian Unge Marco Bo Hansen Per Arnell Michael Nekludov Ole Hyldegaard Magda Lourda Vitor A.P. Martins dos Santos Edoardo Saccenti Steinar Skrede Mattias Svensson Anna Norrby-Teglund 《The Journal of clinical investigation》2021,131(14)
BACKGROUNDNecrotizing soft-tissue infections (NSTIs) are rapidly progressing infections frequently complicated by septic shock and associated with high mortality. Early diagnosis is critical for patient outcome, but challenging due to vague initial symptoms. Here, we identified predictive biomarkers for NSTI clinical phenotypes and outcomes using a prospective multicenter NSTI patient cohort.METHODSLuminex multiplex assays were used to assess 36 soluble factors in plasma from NSTI patients with positive microbiological cultures (n = 251 and n = 60 in the discovery and validation cohorts, respectively). Control groups for comparative analyses included surgical controls (n = 20), non-NSTI controls (i.e., suspected NSTI with no necrosis detected upon exploratory surgery, n = 20), and sepsis patients (n = 24).RESULTSThrombomodulin was identified as a unique biomarker for detection of NSTI (AUC, 0.95). A distinct profile discriminating mono- (type II) versus polymicrobial (type I) NSTI types was identified based on differential expression of IL-2, IL-10, IL-22, CXCL10, Fas-ligand, and MMP9 (AUC >0.7). While each NSTI type displayed a distinct array of biomarkers predicting septic shock, granulocyte CSF (G-CSF), S100A8, and IL-6 were shared by both types (AUC >0.78). Finally, differential connectivity analysis revealed distinctive networks associated with specific clinical phenotypes.CONCLUSIONSThis study identifies predictive biomarkers for NSTI clinical phenotypes of potential value for diagnostic, prognostic, and therapeutic approaches in NSTIs.TRIAL REGISTRATIONClinicalTrials.gov .FUNDINGCenter for Innovative Medicine (CIMED); Region Stockholm; Swedish Research Council; European Union; Vinnova; Innovation Fund Denmark; Research Council of Norway; Netherlands Organisation for Health Research and Development; DLR Federal Ministry of Education and Research; and Swedish Children’s Cancer Foundation. NCT01790698相似文献
999.
Several studies have reported that women with ovarian cancer and a BRCA1 or BRCA2 mutations have better survival than women with ovarian cancer and no mutation. Potential reasons for this include possible differences in histologic subtype, stage, grade and response to chemotherapy, but some of the difference in survival may be due to systematic bias, i.e. a difference in survival rates for women who do and who do not undergo genetic testing. We estimated the survival rate in 1423 ovarian cancer patients from Ontario who had genetic testing and compared this with the survival rate for all 3367 ovarian cancer patients from the province from whom the tested sample was derived. Tested women had a 10‐year survival of 54.5%, compared to 35.8% for all patients in the province. We evaluated the extent to which three different methods of adjustment eliminated the observed difference. The adjusted rates for the tested cohort were closer to the provincial average, but each adjustment method resulted in a modest over‐estimate of 10‐year survival, ranging from 6.1% to 10.0%. The mortality advantage for tested women was due, in part, to a lower than expected mortality rate of tested women in the period following genetic testing. 相似文献
1000.
Louise Rovsing Martin Fredensborg Rath Morten Møller 《The Journal of comparative neurology》2013,521(17):4061-4074
Vasopressin (AVP) is both a neuroendocrine hormone located in magnocellular neurosecretory neurons of the hypothalamus of mammals but also a neurotransmitter/neuromodulator in the parvocellular suprachiasmatic nucleus (SCN). The SCN is the endogenous clock of the brain and exhibits a prominent circadian AVP rhythm. We have in this study of the brown 129sv mouse and the visual blind cone–rod homeobox gene knock out mouse (Crx?/?) with degeneration of the retinal rods and cones, but a preserved non‐image forming optic system, studied the temporal Avp expression in both the neurosecretory magnocellular and parvocellular vasopressinergic systems in both genotypes. We here present a detailed mapping of all classical hypothalamopituitary and accessory magnocellular nuclei and neurons in the hypothalamus by use of immunohistochemistry and in situ hybridization in both genotypes. Semiquantitative in situ hybridization revealed a very high expression of Avp mRNA in all the magnocellular nuclei compared with a much lower level in the parvocellular suprachiasmatic nucleus. In a series of mice killed every 4 hours, the Avp mRNA expression in the SCN showed a significant daily rhythm with a zenith at late day time and nadir during the dark in both the Crx?/? and the wild type mouse. None of the magnocellular neurosecretory neurons exhibited a diurnal vasopressin expression. Light stimulation of both genotypes during the dark period did not change the Avp expression in the SCN. This shows that Avp expression in the mouse SCN is independent of Crx‐regulated photoreceptor systems. J. Comp. Neurol. 521:4061–4074, 2013. © 2013 Wiley Periodicals, Inc. 相似文献