全文获取类型
收费全文 | 3651篇 |
免费 | 314篇 |
国内免费 | 113篇 |
专业分类
耳鼻咽喉 | 22篇 |
儿科学 | 154篇 |
妇产科学 | 45篇 |
基础医学 | 466篇 |
口腔科学 | 80篇 |
临床医学 | 537篇 |
内科学 | 807篇 |
皮肤病学 | 74篇 |
神经病学 | 189篇 |
特种医学 | 426篇 |
外国民族医学 | 1篇 |
外科学 | 308篇 |
综合类 | 76篇 |
一般理论 | 1篇 |
预防医学 | 358篇 |
眼科学 | 53篇 |
药学 | 282篇 |
中国医学 | 3篇 |
肿瘤学 | 196篇 |
出版年
2021年 | 25篇 |
2020年 | 23篇 |
2019年 | 48篇 |
2018年 | 57篇 |
2017年 | 28篇 |
2016年 | 52篇 |
2015年 | 66篇 |
2014年 | 73篇 |
2013年 | 116篇 |
2012年 | 116篇 |
2011年 | 145篇 |
2010年 | 97篇 |
2009年 | 112篇 |
2008年 | 133篇 |
2007年 | 174篇 |
2006年 | 155篇 |
2005年 | 182篇 |
2004年 | 104篇 |
2003年 | 130篇 |
2002年 | 112篇 |
2001年 | 103篇 |
2000年 | 98篇 |
1999年 | 87篇 |
1998年 | 125篇 |
1997年 | 123篇 |
1996年 | 137篇 |
1995年 | 93篇 |
1994年 | 81篇 |
1993年 | 81篇 |
1992年 | 61篇 |
1991年 | 76篇 |
1990年 | 63篇 |
1989年 | 88篇 |
1988年 | 82篇 |
1987年 | 88篇 |
1986年 | 73篇 |
1985年 | 85篇 |
1984年 | 48篇 |
1983年 | 40篇 |
1982年 | 44篇 |
1981年 | 33篇 |
1980年 | 41篇 |
1979年 | 34篇 |
1978年 | 29篇 |
1977年 | 36篇 |
1976年 | 48篇 |
1975年 | 41篇 |
1974年 | 16篇 |
1973年 | 19篇 |
1970年 | 23篇 |
排序方式: 共有4078条查询结果,搜索用时 15 毫秒
71.
72.
Isolation and characterization of propagable cell lines (HUNC) from the androgen-sensitive Dunning R3327H rat prostatic adenocarcinoma 总被引:1,自引:0,他引:1
Presnell SC; Borchert KM; Glover WJ; Gregory CW; Mohler JL; Smith GJ 《Carcinogenesis》1998,19(4):585-590
The Dunning H rat prostate tumor (R3327H) is a widely used experimental
model of human prostatic adenocarcinoma (CaP). The Dunning H tumor has been
characterized as androgen-sensitive, androgen-receptor (AR) positive,
prostate-specific antigen and prostatic acid phosphatase (PAP) positive. To
date, the tumor has been maintained by serial passage in vivo because of
the lack of an in vitro cell line that retains the characteristics of the
in vivo tumor. The objective of the present study was to establish a
propagable cell line from R3327H adenocarcinoma that maintained androgen
sensitivity and expression of AR, PSA and PAP. Tissue harvested from an in
vivo R3327H tumor was dissociated with collagenase and placed into
Richter's improved media (with supplements). A cytokeratin-positive
epithelial cell line (HUNC- E) and a vimentin-positive stromal cell line
(HUNC-S) were generated from the primary culture, subcultured continuously
for >300 days, and passaged >50 times. Survival of the HUNC-E cell
line in vitro depended on several media supplements, including
nicotinamide, insulin, transferrin, selenium and epidermal growth factor
(EGF). HUNC-E cells expressed AR and produced PSA and PAP throughout the
culture period, as confirmed by immunocytochemistry and Western blot
analyses. Addition of 14 nM testosterone (T) or dihydrotestosterone (DHT)
to HUNC-E cells, stimulated DNA synthesis as well as anchorage-independent
growth and PSA production, which demonstrated the androgen-sensitive nature
of the cells in vitro. When HUNC-E and HUNC-S cells were combined in a 3:1
ratio and introduced subcutaneously into syngeneic male hosts, tumors
formed in 2/3 animals with an average latency of 7 months. RT-PCR and
immunocytochemical characterization of the HUNC cell lines revealed that
the cells expressed several growth factors and their cognate receptors,
including HGF, TGF-alpha and the TGF-betas, indicating the establishment of
potential autocrine loops in the neoplastic cells. The HUNC-E and HUNC-S
CaP cell lines, which retain the characteristics of the epithelial and
stromal components of the in vivo R3327H tumor, will allow a more thorough
and informative molecular and biological analysis of prostatic
adenocarcinoma.
相似文献
73.
Previous work has shown that sustained increased and decreased cell
proliferation, induced by dietary zinc deficiency and caloric restriction
respectively, influence the course of N- nitrosomethylbenzylamine
(NMBA)-induced esophageal carcinogenesis in rats. The present study
considered whether the increased cell proliferation and esophageal tumor
incidence induced by zinc deficiency are reversed upon zinc replenishment.
Weanling rats were maintained initially on a deficient diet containing 4
p.p.m. zinc. After 5 weeks, carcinogen-treated animals were given six
intragastric doses of NMBA (2 mg/kg twice weekly). Controls were untreated.
After the second NMBA dose, the rats were divided into three dietary
groups. One group was continued on the deficient diet, while the other two
groups were switched to diets containing either 75 or 200 p.p.m. zinc, with
half of the members in each group fed ad libitum and half pair-fed with
deficient rats. NMBA-untreated controls were similarly replenished. At
various time points, esophageal cell proliferation was assessed in five
animals from each group by immunohistochemical detection of cells in S
phase, with in vivo 5-bromo-2'deoxyuridine labeling. At 11 weeks after the
first dose, esophageal tumor incidence was greatly reduced, from 100% in
the deficient group to 26 and 14% respectively in the replenished groups
fed ad libitum 75 and 200 p.p.m. zinc and to 14 and 11% respectively in the
replenished groups pair-fed 75 and 200 p.p.m. zinc. In addition, the number
of tumors per esophagus was reduced from 9.93 +/- 4.25 in deficient rats,
to a range of 0.11 +/- 0.31-0.30 +/- 0.54 in replenished animals. Following
zinc replenishment, esophageal cell proliferation, as measured by labeling
index (LI), the number of labeled cells and the total number of cells, was
markedly decreased in NMBA-untreated and -treated esophagi as compared with
those in corresponding deficient esophagi. Thus, the esophageal cell
proliferation induced by zinc deficiency is reversed by zinc replenishment
and replenished animals have a markedly lower incidence of esophageal
tumors.
相似文献
74.
Murray DR Carlson GW Greenlee R Alazraki N Fry-Spray C Hestley A Poole R Blais M Timbert DS Vansant J 《The American surgeon》2000,66(8):763-767
Sentinel lymph node (SLN) biopsy is revolutionizing the surgical management of primary malignant melanoma. It allows accurate nodal staging which targets patients who may benefit from regional lymphadenectomy and systemic therapy. This is a retrospective review of patients treated at Emory University for stage I and II malignant melanoma with gamma probe-guided SLN biopsy from 1/1/94 to 6/30/98. Three hundred sixty patients (males 228, females 132) were identified. Primary melanoma sites included: head and neck 58, trunk 148, and extremities 154 (upper 71, lower 83). Primary tumor staging was T1 9, T2 134, T3 153, and T4 64. SLNs were successfully identified in 99.7 per cent of patients and 98.9 per cent of nodal basins mapped. In 275 (76.6%) cases a single draining nodal basin was identified. In 84 (23.3%) cases there were multiple draining nodal basins. Positive SLNs were identified in 63 patients (17.5%). SLN positivity by tumor staging was T1 0 per cent, T2 9.0 per cent, T3 22.2 per cent, and T4 26.6 per cent. The overall recurrence rate was 11.9 per cent. Recurrences by SLN status were SLN+, 27 per cent, and SLN-, 8.8 per cent. Regional recurrence occurred in 7 (2.4%) of the 297 with negative SLN biopsies and 7 (11.1%) of the 63 with positive SLN biopsies. Dynamic lymphoscintigraphy and gamma probe-guided SLN localization was successful in more than 98 per cent of cases. Patients with negative SLN biopsies have a low risk of recurrence. 相似文献
75.
Graham G Dark A Hilary Calvert Robert Grimshaw Christopher Poole Ken Swenerton Stan Kaye Robert Coleman Gordon Jayson Tien Le Susan Ellard Marc Trudeau Paul Vasey Marta Hamilton Terri Cameron Emma Barrett Wendy Walsh Lynn McIntosh Elizabeth A Eisenhauer 《Journal of clinical oncology》2005,23(9):1859-1866
PURPOSE: Liposomal lurtotecan (OSI-211) is a liposomal formulation of the water-soluble topoisomerase I inhibitor lurtotecan (GI147211), which demonstrated superior levels of activity compared with topotecan in preclinical models. We studied two schedules of OSI-211 in a randomized design in relapsed ovarian cancer to identify the more promising of the two schedules for further study. PATIENTS AND METHODS: Eligible patients had measurable epithelial ovarian, fallopian, or primary peritoneal cancer that was recurrent after one or two prior regimens of chemotherapy. Patients were randomly assigned to receive either arm A (OSI-211 1.8 mg/m(2)/d administered by 30-minute intravenous infusion on days 1, 2, and 3 every 3 weeks) or arm B (OSI-211 2.4 mg/m(2)/d administered by 30-minute intravenous infusion on days 1 and 8 every 3 weeks). The primary outcome measure was objective response, which was confirmed by independent radiologic review, and a pick the winner statistical design was used to identify the schedule most likely to be superior. RESULTS: Eighty-one patients were randomized between October 2000 and September 2001. The hematologic toxic effects were greater on arm A than on arm B (grade 4 neutropenia, 51% v 22%, respectively), as was febrile neutropenia (26% v 2.4%, respectively). Of the 80 eligible patients, eight patients (10%) had objective responses; six responders (15.4%; 95% CI, 6% to 30%) were in arm A and two responders (4.9%; 95% CI, 1% to 17%) were in arm B. CONCLUSION: The OSI-211 daily for 3 days intravenous schedule met the statistical criteria to be declared the winner in terms of objective response. This schedule was also associated with more myelosuppression than the schedule of OSI-211 administered in arm B. 相似文献
76.
77.
Victoria N. Poole Kausar Abbas Trey E. Shenk Evan L. Breedlove Katherine M. Breedlove Meghan E. Robinson 《Developmental neuropsychology》2014,39(6):459-473
With growing evidence of long-term neurological damage in individuals enduring repetitive head trauma, it is critical to detect lower-level damage accumulation for the early diagnosis of injury in at-risk populations. Proton magnetic resonance spectroscopic scans of the dorsolateral prefrontal cortex and primary motor cortex were collected from high school American (gridiron) football athletes, prior to and during their competition seasons. Although no concussions were diagnosed, significant metabolic deviations from baseline and non-collision sport controls were revealed. Overall the findings indicate underlying biochemical changes, consequential to repetitive hits, which have previously gone unnoticed due to a lack of traditional neurological symptoms. 相似文献
78.
79.
80.
The Newcastle-Ottawa scale (NOS) is one of many scales used to judge the quality of observational studies in systematic reviews. It was criticized for its arbitrary definitions of quality items in a commentary in 2010 in this journal. That commentary was cited 1,250 times through December 2016. We examined the citation history of this commentary in a random sample of 100 full papers citing it, according to the Web of Science. Of these, 96 were systematic reviews, none of which quoted the commentary directly. All but 2 of the 96 indirect quotations (98%) portrayed the commentary as supporting use of the NOS in systematic reviews when, in fact, the opposite was the case. It appears that the vast majority of systematic review authors who cited this commentary did not read it. Journal reviewers and editors did not recognize and correct these major quotation errors. Authors should read each source they cite to make sure their direct and indirect quotations are accurate. Reviewers and editors should do a better job of checking citations and quotations for accuracy. It might help somewhat for commentaries to include abstracts, so that the basic content can be conveyed by PubMed and other bibliographic resources. 相似文献