全文获取类型
收费全文 | 2080篇 |
免费 | 95篇 |
国内免费 | 114篇 |
专业分类
儿科学 | 69篇 |
妇产科学 | 13篇 |
基础医学 | 208篇 |
口腔科学 | 27篇 |
临床医学 | 223篇 |
内科学 | 459篇 |
皮肤病学 | 43篇 |
神经病学 | 64篇 |
特种医学 | 452篇 |
外国民族医学 | 1篇 |
外科学 | 344篇 |
综合类 | 46篇 |
预防医学 | 85篇 |
眼科学 | 27篇 |
药学 | 128篇 |
中国医学 | 3篇 |
肿瘤学 | 97篇 |
出版年
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 22篇 |
2020年 | 9篇 |
2019年 | 18篇 |
2018年 | 26篇 |
2016年 | 25篇 |
2015年 | 31篇 |
2014年 | 34篇 |
2013年 | 63篇 |
2012年 | 55篇 |
2011年 | 60篇 |
2010年 | 66篇 |
2009年 | 63篇 |
2008年 | 67篇 |
2007年 | 106篇 |
2006年 | 70篇 |
2005年 | 92篇 |
2004年 | 50篇 |
2003年 | 59篇 |
2002年 | 46篇 |
2001年 | 47篇 |
2000年 | 45篇 |
1999年 | 45篇 |
1998年 | 101篇 |
1997年 | 99篇 |
1996年 | 108篇 |
1995年 | 70篇 |
1994年 | 66篇 |
1993年 | 67篇 |
1992年 | 23篇 |
1991年 | 46篇 |
1990年 | 39篇 |
1989年 | 60篇 |
1988年 | 44篇 |
1987年 | 59篇 |
1986年 | 40篇 |
1985年 | 53篇 |
1984年 | 26篇 |
1983年 | 21篇 |
1982年 | 29篇 |
1981年 | 24篇 |
1980年 | 39篇 |
1979年 | 17篇 |
1978年 | 20篇 |
1977年 | 20篇 |
1976年 | 30篇 |
1975年 | 18篇 |
1974年 | 6篇 |
1973年 | 9篇 |
排序方式: 共有2289条查询结果,搜索用时 15 毫秒
51.
Miller MD Mcmahon PA Port J Warner JJ 《American journal of orthopedics (Belle Mead, N.J.)》1995,24(8):635-636
A case of an unusual synovial cyst with both intra- and extraosseous components found in the proximal humerus of a patient with osteoarthritis is presented. The importance of this lesion is that it should be recognized as a manifestation of the underlying osteoarthritis and does not represent a more serious primary lesion. 相似文献
52.
13年室间质控菌株鉴定工作的实践和体会 总被引:1,自引:0,他引:1
为了提高菌株鉴定水平, 我们自1985~1998 年参加了省临检中心细菌室间质控工作, 共鉴定下发菌株142 株,鉴定正确131 株(占92.25% ), 误检11 株(7.75% )。本文总结了鉴定工作的经验, 并对误检原因进行分析。认为理论、实践和学科新进展是提高鉴定水平的关键 相似文献
53.
Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant 总被引:41,自引:0,他引:41
Wolfe RA Ashby VB Milford EL Ojo AO Ettenger RE Agodoa LY Held PJ Port FK 《The New England journal of medicine》1999,341(23):1725-1730
BACKGROUND AND METHODS: The extent to which renal allotransplantation - as compared with long-term dialysis - improves survival among patients with end-stage renal disease is controversial, because those selected for transplantation may have a lower base-line risk of death. In an attempt to distinguish the effects of patient selection from those of transplantation itself, we conducted a longitudinal study of mortality in 228,552 patients who were receiving long-term dialysis for end-stage renal disease. Of these patients, 46,164 were placed on a waiting list for transplantation, 23,275 of whom received a first cadaveric transplant between 1991 and 1997. The relative risk of death and survival were assessed with time-dependent nonproportional-hazards analysis, with adjustment for age, race, sex, cause of end-stage renal disease, geographic region, time from first treatment for end-stage renal disease to placement on the waiting list, and year of initial placement on the list. RESULTS: Among the various subgroups, the standardized mortality ratio for the patients on dialysis who were awaiting transplantation (annual death rate, 6.3 per 100 patient-years) was 38 to 58 percent lower than that for all patients on dialysis (annual death rate, 16.1 per 100 patient-years). The relative risk of death during the first 2 weeks after transplantation was 2.8 times as high as that for patients on dialysis who had equal lengths of follow-up since placement on the waiting list, but at 18 months the risk was much lower (relative risk, 0.32; 95 percent confidence interval, 0.30 to 0.35; P<0.001). The likelihood of survival became equal in the two groups within 5 to 673 days after transplantation in all the subgroups of patients we examined. The long-term mortality rate was 48 to 82 percent lower among transplant recipients (annual death rate, 3.8 per 100 patient-years) than patients on the waiting list, with relatively larger benefits among patients who were 20 to 39 years old, white patients, and younger patients with diabetes. CONCLUSIONS: Among patients with end-stage renal disease, healthier patients are placed on the waiting list for transplantation, and long-term survival is better among those on the waiting list who eventually undergo transplantation. 相似文献
54.
Rémy M Valli N Brethes D Labrugère C Porté-Durrieu MC Dobrova NB Novikova SP Gorodkov AJ Bordenave L 《Biomaterials》1999,20(3):241-251
In order to improve long-term patency of vascular grafts, the promising concept of endothelial cell seeding is actually under investigation. Our laboratory tested a polyester coated with albumin and chitosan which permits a rapid colonization by human umbilical vein endothelial cells (HUVEC) and it seems relevant to test in vitro the expression of adhesive molecules expressed by cells with regard to the inflammatory process. We studied intercellular adhesion molecule-1 (ICAM-1) expression and focused our work on the determination of ICAM-1 sites expressed per adherent cell lining the biomaterial, thus in situ, in comparison to control HUVEC on plastic wells: the results obtained by binding experiments were correlated to flow cytometry analyses and showed that the polyester does not induce a proinflammatory state and that HUVEC covering the structure are able to respond to a stimulus. 相似文献
55.
为探讨体外循环(CPB)导致心脏植物神经系统(CAS)损伤的机理,了解温血心停跳液能否防止CPB后心率变异性(HRV)的降低,采用对照方法观察了温血心停跳液与冷晶体心停跳液对狗HRV的影响。结果显示:CPB后温血心停跳液组(WB组)和冷晶体心停跳液组(CC组)的全频谱(TP)、低频(LF)和高频(HF)均较术前明显降低(P<0.05),而且CC组比WB组降低更明显(P<0.05),但LF/HF在组内及组间均无明显变化(P>0.05)。CPB后24小时平均心率(MHR)明显增加(P<0.05),且CC组高于WB组(P<0.05)。本研究表明:采用温血心停跳液或冷晶体心停跳液的CPB不会干扰CAS平衡,但均能使HRV降低,温血心停跳液不能防止HRV损害。 相似文献
56.
The palpation and enucleation of occult insulinomas (less than 15 mm) can be a difficult surgical problem even with good arteriographic localization. In the authors' limited experience, confirmation of arteriographic findings by pancreatic venous sampling provided little additional localizing information. However, if arteriography is negative or equivocal, venous sampling can indicate the segment of pancreas to be "blindly" resected if the adenoma is not palpable. Venous sampling may be misleading in polyendocrine syndromes because of the frequency of multiple adenomas and variable hormone production. 相似文献
57.
58.
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
59.
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
60.
Chemotherapy induces the expression of cyclooxygenase-2 in non-small cell lung cancer. 总被引:2,自引:0,他引:2
Nasser K Altorki Jeffrey L Port Fan Zhang Dragan Golijanin Howard T Thaler Anna J Duffield-Lillico Kotha Subbaramaiah Andrew J Dannenberg 《Clinical cancer research》2005,11(11):4191-4197
PURPOSE: To determine the effect of taxane-based chemotherapy on intratumoral levels of cyclooxygenase-2 (COX-2) and prostaglandin E(2) (PGE(2)) in patients with non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Lung specimens obtained at the time of surgery were used to measure levels of COX-2 and PGE(2) in tumors and adjacent nontumorous tissues in three subsets of NSCLC patients who underwent: (A) surgical resection only (n = 16); (B) surgical resection after preoperative taxane-based chemotherapy (n = 13); or (C) surgical resection after preoperative chemotherapy coadministered with the selective COX-2 inhibitor, celecoxib 400 mg bid (n = 17). RESULTS: Levels of intratumoral PGE(2) were nearly 3-fold higher among patients who received preoperative chemotherapy compared with those treated by surgery alone (P < 0.001). This difference was abrogated by the addition of celecoxib to preoperative chemotherapy (P < 0.001). Amounts of intratumoral COX-2 were approximately 3-fold higher in groups of patients who received preoperative chemotherapy with celecoxib (P < 0.0001) or without celecoxib (P < 0.001), compared with the group who underwent surgical resection only. Importantly, statistically significant positive correlations between COX-2 and PGE(2) were observed in the surgery only (r = 0.502, P = 0.047) and preoperative chemotherapy groups (r = 0.740, P = 0.004); this correlation was abrogated when celecoxib was given with chemotherapy (r = 0.005, P = 0.98). CONCLUSIONS: Treatment with chemotherapy led to increased amounts of COX-2 and PGE(2) in NSCLC. Cotreatment with celecoxib abrogated the increase in levels of PGE(2) but not COX-2 induced by chemotherapy. Importantly, these results clearly show that levels of a pharmacologic target (i.e., COX-2) can be affected by both the intrinsic molecular properties of a tumor and therapy. 相似文献