全文获取类型
收费全文 | 1483篇 |
免费 | 77篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 121篇 |
妇产科学 | 22篇 |
基础医学 | 111篇 |
口腔科学 | 36篇 |
临床医学 | 247篇 |
内科学 | 336篇 |
皮肤病学 | 16篇 |
神经病学 | 52篇 |
特种医学 | 226篇 |
外科学 | 135篇 |
综合类 | 36篇 |
预防医学 | 46篇 |
眼科学 | 52篇 |
药学 | 71篇 |
1篇 | |
肿瘤学 | 56篇 |
出版年
2020年 | 10篇 |
2019年 | 11篇 |
2018年 | 19篇 |
2017年 | 20篇 |
2016年 | 22篇 |
2015年 | 28篇 |
2014年 | 27篇 |
2013年 | 29篇 |
2012年 | 33篇 |
2011年 | 44篇 |
2010年 | 49篇 |
2009年 | 60篇 |
2008年 | 38篇 |
2007年 | 30篇 |
2006年 | 32篇 |
2005年 | 27篇 |
2004年 | 27篇 |
2003年 | 18篇 |
2002年 | 27篇 |
2001年 | 30篇 |
2000年 | 20篇 |
1999年 | 23篇 |
1998年 | 90篇 |
1997年 | 89篇 |
1996年 | 91篇 |
1995年 | 59篇 |
1994年 | 56篇 |
1993年 | 45篇 |
1992年 | 24篇 |
1991年 | 30篇 |
1990年 | 22篇 |
1989年 | 38篇 |
1988年 | 36篇 |
1987年 | 43篇 |
1986年 | 20篇 |
1985年 | 35篇 |
1984年 | 28篇 |
1983年 | 26篇 |
1982年 | 19篇 |
1981年 | 20篇 |
1980年 | 13篇 |
1979年 | 8篇 |
1978年 | 15篇 |
1977年 | 21篇 |
1976年 | 15篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1973年 | 10篇 |
1971年 | 9篇 |
1968年 | 7篇 |
排序方式: 共有1574条查询结果,搜索用时 15 毫秒
71.
72.
Ventral hernia repair: a study of current practice 总被引:5,自引:5,他引:0
Ventral wall hernias are common; despite this, there are no guidelines on the best surgical management. The aim of this study
was to examine the types of repair in use for abdominal wall hernias in the West of Scotland over a 3-month period. Data were
gathered on 120 patients. There were 60 incisional, 32 umbilical, and 28 epigastric hernias. The main indication for repair
was pain (78%), while 12 patients (10%), presented acutely with incarceration or strangulation. The most common method of
repair was sutured (55%), followed by mesh (29%) and Mayo repair (16%). There was no correlation between use of mesh and hernia
size or whether repair was for a recurrent hernia. Surgical practice varies widely in the repair of ventral wall hernias.
Clinical trials are required to establish the best method of repair for this common condition.
Electronic Publication 相似文献
73.
McCullough JA Evoy D Sweeney KJ Meyers C Ravi N Keeling N Byrne PJ Reynolds JV 《Irish journal of medical science》2003,172(3):132-135
Background Gastric carcinoma is a significant cause of death in Ireland. Surgery offers the best option of cure, but the five-year survival
following resection remains dismal at 10–15%. Experience from Japan and from some Western units suggest that an extended (D2)
lymphadenectomy in association with gastrectomy increases the prospect of cure, but concern about the morbidity and mortality
of this operation and lack of evidence from randomised studies has limited its acceptance.
Aims This study reports the experience of a specialist upper gastrointestinal unit with D2 gastrectomy in a four-year audit.
Methods Sixty-two resections were performed for gastric cancer. Results Nineteen patients were deemed unsuitable for the D2 procedure
and underwent a more limited lymphadenectomy (DO or D1). Forty-three patients underwent D2 resection, 12 with an oesophagogastrectomy,
22 with total gastrectomy and nine with a sub-total distal resection. Eight patients undergoing D2 resection had extended
resections, five with splenectomy and three with a distal pancreatectomy. Post-operative complications occurred in 31% of
patients. Thirty-day and 90-day mortality were zero. Median survival was 822 days in the D2 group (range 120–1,320).
Conclusions These results show that a D2 gastrectomy can be performed with a low morbidity and mortality and a median survival of greater
than two years. 相似文献
74.
Background The contribution of dysmotility to dysphagia in oesophageal cancer is unclear.
Aim To examine oesophageal motility in patients with oesophageal carcinoma and to assess the effect of chemoradiotherapy on motility.
Methods Stationary manometry and 24-hour pH-metry were performed in 12 patients with oesophageal carcinoma and one week following
completion of chemoradiotherapy using 5-fluorouracil (5-FU), cisplatin and 40Gy radiotherapy.
Results All patients had abnormal motility prior to treatment. Peristalsis was impaired in 11 patients with a mean (SD) of 25% (9)
of waves normally propagated. Eight patients had 20% or more simultaneous waves. Following chemoradiotherapy, the percentage
of waves normally propagated increased from 25% (9) to 52% (10) (p < 0.03) and normal peristalsis was restored in four patients.
The percentage of simultaneous waves decreased from 38% (11) to 21.6% (10) (p=0.129) while the percentage of dropped or increased
waves decreased from 20% (11) to 8.3% (4) (p=0.264).
Conclusions Oesophageal motility is disturbed in oesophageal cancer. Dysphagia in oesophageal cancer may be partly explained by oesophageal
dysmotility. This is improved by chemotherapy. 相似文献
75.
BACKGROUND: Bovine lens epithelial cells in culture revealed a high sensitivity against micromolar concentrations of linoleic acid. To prove the assumption that unsaturated free fatty acids are risk factors for cataractogenesis, human lens cell lines are needed. Furthermore, the reactivation of nucleus-containing fiber cells to mitotic growth may hint at their role in after cataract genesis. MATERIAL AND METHODS: Epithelium-capsule-preparations obtained by capsulorhexis were cultured in serum containing medium. Subculturing of these adult human lens epithelial cells was done by trypsinization. Fiber cell bundles from the equator region of a fetal human lens were transferred into culture medium. Aggregates of nucleus containing fiber cells were isolated from floating fiber cell bundles by trypsinization. Subculturing and cryoconservation of suitable cell lines. RESULTS: Primary culture of epithelium-capsule-preparations results in flattening, migration and proliferation of adult human lens epithelial cells. Nucleus containing fiber cells were reactivated to mitotic growth after adhesion to a suitable substratum. Established cell lines were received from adult human lens epithelial cells and fetal human fiber cells after repeated subculturing. CONCLUSIONS: Lens-capsule-preparations available from cataract surgery are well suited for the isolation of human lens cell lines, which were needed for testing cytotoxicity of drugs and for tracing of cataractogenic risk factors. The finding that nucleus containing fiber cells from the equator of human lenses can be reactivated to proliferating cells let us suppose, that these cells, which can not be removed easily from the posterior lens capsule, contribute to the after cataract formation. 相似文献
76.
Struck RF Tiwari A Friedman HS Keir S Morgan LR Waud WR 《Cancer chemotherapy and pharmacology》2001,48(1):47-52
PURPOSE: The purpose of this investigation was to compare the antitumor activities of a series of acyl derivatives of 4-demethylpenclomedine (DM-PEN), the major plasma metabolite of penclomedine (PEN) observed to be an active antitumor agent in vivo and non-neurotoxic in a rat model with that of DM-PEN. METHODS: Acyl derivatives were prepared from DM-PEN and evaluated in vivo against human MX-1 breast tumor xenografts implanted subcutaneously (s.c.) or intracerebrally (i.c.). Several derivatives were also evaluated against other human tumor xenografts and murine P388 leukemia cell lines. RESULTS: Several of the acyl derivatives were found to be superior to DM-PEN against MX-1, human ZR-75-1 breast tumor, human U251 CNS tumor and the P388 leukemia parent cell line and lines resistant to cyclophosphamide and carmustine. 4-Demethyl-4-methoxyacetylpenclomedine showed inferior activity to current clinical brain tumor drugs against a glioma cell line, superior activity to temozolomide and procarbazine against the derived mismatch repair-deficient cell line, and superior activity to cyclophosphamide and carmustine but inferior activity to temozolomide against two ependymoma cell lines, all of which were implanted s.c. CONCLUSION: Proposed mechanisms of activation and action of DM-PEN and the acyl derivatives support the potential clinical superiority of the acyl derivatives. 相似文献
77.
Henry S. Friedman Anthony E. Pegg Stewart P. Johnson Natalia A. Loktionova M. Eileen Dolan Paul Modrich Robert C. Moschel Robert Struck Thomas P. Brent Susan Ludeman Nancy Bullock Cynthia Kilborn Steve Keir Qing Dong Darell D. Bigner O. Michael Colvin 《Cancer chemotherapy and pharmacology》1999,43(1):80-85
Purpose: The human medulloblastoma cell line D283 Med (4-HCR), a line resistant to 4-hydroperoxycyclophosphamide (4-HC), displays
enhanced␣repair of DNA interstrand crosslinks induced by phosphoramide mustard. D283 Med (4-HCR) cells are cross-resistant
to 1,3-bis(2-chloroethyl)-1-nitrosourea, but partial sensitivity is restored after elevated levels of O
6-alkylguanine-DNA alkyltransferase (AGT) are depleted by O
6-benzylguanine (O
6-BG). Studies were conducted to define the activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide against D283 Med (4-HCR)
after AGT is depleted by O
6-BG. Methods: Limiting dilution and xenograft studies were conducted to define the activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide
with or without O
6-BG. Results: The activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide against D283 Med (4-HCR) was increased after AGT depletion
by O
6-BG preincubation. Similar studies with Chinese hamster ovary cells, with or without stable transfection with a plasmid expressing
the human AGT protein, revealed that the AGT-expressing cells were significantly less sensitive to 4-HC and 4-hydroperoxydidechlorocyclophosphamide.
Reaction of DNA with 4-HC, phosphoramide mustard, or acrolein revealed that only 4-HC and acrolein caused a decrease in AGT
levels. Conclusions: We propose that a small but potentially significant part of the cellular toxicity of cyclophosphamide in these cells is
due to acrolein, and that this toxicity is abrogated by removal of the acrolein adduct from DNA by AGT.
Received: 17 February 1998 / Accepted: 20 May 1998 相似文献
78.
Cuppen JG Van den Brink PJ Camps E Uil KF Brock TC 《Aquatic toxicology (Amsterdam, Netherlands)》2000,48(2-3):233-250
Effects of chronic application of the fungicide Derosal(R) (active ingredient carbendazim) were studied in indoor macrophyte-dominated freshwater microcosms. The concentrations (0, 3.3, 33, 100, 330 and 1000 μg/l) were kept at a constant level for 4 weeks. This paper is the first of a series of two, and describes the fate of carbendazim and its effects on water quality parameters, breakdown of POM, and responses of macroinvertebrates. Carbendazim proved very persistent in the water layer. Values for t(12) varied between 6 and 25 weeks, and decreased with the treatment level. Significant effects on water quality parameters (DO, pH, alkalinity, conductivity) could not be demonstrated. After 4 weeks of incubation, the breakdown of Populus leaves was significantly slower at the two highest carbendazim concentrations. The macroinvertebrate community was seriously affected by carbendazim application, with Oligochaeta, Turbellaria, Hirudinea and some Crustacea as the most sensitive groups. The snail Bithynia decreased in numbers, but other gastropods increased in numbers. Safety factors as proposed by the Uniform Principles (European Union) for the risk assessment of pesticides, to be multiplied with toxicity data of the standard test species (Daphnia, fish, algae), appeared to ensure adequate protection of sensitive populations present in the microcosms. 相似文献
79.
Reynolds RC Tiwari A Harwell JE Gordon DG Garrett BD Gilbert KS Schmid SM Waud WR Struck RF 《Journal of medicinal chemistry》2000,43(8):1484-1488
Seven new (2-chloroethyl)nitrosocarbamates have been synthesized as potential anticancer alkylating agents. These compounds were designed with carrier moieties that would either act as prodrugs or confer water solubility. All compounds were screened in an in vitro panel of five human tumor cell lines: CAKI-1 (renal), DLD-1 (colon), NCI-H23 (lung), SK-MEL-28 (melanoma), and SNB-7 (CNS). Several agents showed good activity with IC(50) values in the range of 1-10 microg/mL against at least two of the cell lines. One compound, carbamic acid, (2-chloroethyl)nitroso-4-acetoxybenzyl ester (3), was selected for further study in vivo against intraperitoneally implanted P388 murine leukemia. In addition to the aforementioned compound, both carbamic acid, (2-chloroethyl)nitroso-4-nitrobenzyl ester (9) and carbamic acid, (2-chloroethyl)nitroso-2,3,4, 6-tetra-O-acetyl-1-alpha,beta-D-glucopyranose ester (24) were evaluated against subcutaneously implanted M5076 murine sarcoma in mice. None of these compounds were active in vivo. 相似文献
80.
Proteolytic activities of human placental extract are determined with the aid of a sensitive micromethod, based upon the Bratton-Marshall-reaction, and aminoacid-p-nitroanilides as substrates. The activities are differentiated by using 19 substrates, by adding 10 effectors, and by incubating the assays within the pH-range from 6.0--8.4. Besides Oxitocinase- and Aminopeptidase-like activities, a very active neutral peptidase, so far unknown in human placenta, an acid peptidase, e.g. Cathepsin C or Dipeptide-aminopeptidase II, and some other enzymes, not yet indentified by us, are demonstrated. 相似文献